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Mistral Rotary

R

Rotary10-RV

Well Known Member
Offhanded comments made by some in other threads moved me to make comment about the status of Mistral.
Mistral is flying it's own Piper Arrow with their 230 HP turbocharged rotary engine. This aircraft has been flying for a little over a year with great success, no engine failures, and is going to be used for the certification flying. Yes this engine is going to be certified, and I believe will be successful. The HP to weight ratios of all the proposed engines are higher than a compareable Lyc, which is no suprise, that is a strength of the rotary. Fuel burn has been competitive on both their 190 HP O/IO 360 replacement motor, and the 230 HP turbo, a bigger suprise as the rotary has a (incorrect) reputation as a fuel guzzler. Mistral is also developing a Jet-A burning SPARK IGNITION HEAVY FUEL engine. This engine is running NOW and producing good numbers.
This is a major effort to produce a reliable alternate aircraft engine. The engines are not vaporware and are becoming available for purchase. No customer aircraft yet, although that isn't supprising since the engines have only been available for approximatly 7 months. I am providing this as an FYI in the alrternate engines section.
Bill Jepson
Rotary10-RV
 
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thanks bill. i've been watching their site to check for updates as well. do you know anything about steve thomas, and his mistral glasair install?
 
Bill, given much thought to rads and ducting on your 20B installation yet? I'm starting to install my custom built rad and belly scoop now. Impressed with the rad which uses a Visteon type core (can't reveal the source or I will be killed). On my flow bench, it had 1/4 the pressure drop of the commonly used GM/ Harrison evaporator cores so I'm hoping that with my adjustable exit door, the drag penalty will be minimal. I spent hours looking at various under cowl rad setups but space, ducting and or poor flow settled me on the belly scoop. Some flow testing indicated that air from the cowling exit duct would turn the corner into the belly scoop inlet so I had to solve this by fitting a horizontal splitter between the two. Messing up Van's clean design by putting a car engine in it. It will be unique though. :)

I'll be interested to see how Eggenfellner's supercharged 3L Subes perform and cool in the -10 with the cheek mounted rads.
 
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Just be realistic

Rotary10-RV said:
Offhanded comments made by some in other threads moved me to make comment about the status of Mistral. .
Bill Jepson
Rotary10-RV
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Bill those where no doubt my off handed comments. I did make the comment that there is not performance data in 2 years of "flight test" and that I did not think this would ever come to the market (or at least sell many).

Let me ask you this, why would some one buy an engine for $31,000 with out an installation kit or prop. No doubt if installed In a certified aircraft, an installation kit is needed (because the installation must be certified), and no doubt that installation kit would cost say wild guess $10,000. OK. Now what do you get over the IO-360 lycoming that was in there? Faster? Lighter? Better fuel economy? I doubt they have achieved any break though in any area and find it suspicious that they don't publish real performance, fuel and weights after almost 2 years of flying. I would be wrong, please correct me.

I doubt they will sell many to the certified crowd at those prices and think Power Sport rotary kit is a more attractive set up tailored for the experimental RV'er market. Than there is the roll your own Real World solutions path to a home grown rotary setup, which is by far the most cost effective way to a rotary engine.

As far as the experimental group. If you can go the Real World solution and do a do-it-yourself rotary for say $12,000 to $16,000 are you going to pay just $31,000. I am sure it is great stuff but we have to temper our enthusiasm for reality an VALUE / bang for the bucks.

I noticed the only "customer picture" is a Glasair under construction. I also noticed they have reduced the price! So one Piper flying some where for some unknown hours and one hanger project? I would NOT send my money in, today, 7 months from now or 2 years from now or ever unless they can show some real performance and specs independently verified. I just hate to see fellow RV'ers loose money. Mistral market and customer base seems to be muddled. They came out aiming at the certified market? They are dedicated to the experimental market? Prices are reduced? There just seems to me a little shakiness to it all. Check out Power Sport first. They are proven in RV's and have known specs, performance and was tested in the RVator in the last year or so.

I hope the reduction drive turns out to be a great thing. I think you asked or someone asked and they want $6000-$7000 for the drive? That kind of takes the price advantage out of the rotary, when a new C/S prop direct drive Lycoming cost less than $20,000.


I hate to be the pisser in the group but someone has to temper unbridled enthusiasm. NO WHERE DID I SAY IT WAS BAD, and I only experessend my personal OPINION, based on seeing dozens of these NEW and improved engines not make an impact, at least at those prices. I suspect they want to charge certitifed approved aircraft engine prices and want the experimental guys to pay it and do their flight test. I just don't think that is going to happen. I could be wrong. At the rate they are going I doubt you will see much progress and it will fade away when their money runs out and there is not enough "deposits" coming in. There is a reason the Lycoming's are still being made after 50 years by three manufactures. George
 
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rv10 mistral

I think the first rotary RV-10 will be danish,the airplane is almost ready and
engine delivery should be soon it will hopefully fly in a few months,you can follow the progress on their homesite www.rv10.dk

j?rn m?ller
 
Powersport's website is defunct and with the loss of one of the RV8s last year, there appears to be now more news. A shame as this one was well engineered IMHO.
 
rv6ejguy said:
Powersport's website is defunct and with the loss of one of the RV8s last year, there appears to be now more news. A shame as this one was well engineered IMHO.
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Powersport's site is back up though they continue to be hanging on by their fingernails. The plane (Jim Clark's) that went down had an electrical failure not engine. Sad as it is a well concieved package.
Bill Jepson
 
gmcjetpilot said:
Bill those where no doubt my off handed comments. I did make the comment that there is not performance data in 2 years of "flight test" and that I did not think this would ever come to the market (or at least sell many).

I doubt they will sell many to the certified crowd at those prices and think Power Sport rotary kit is a more attractive set up tailored for the experimental RV'er market. Than there is the roll your own Real World solutions path to a home grown rotary setup, which is by far the most cost effective way to a rotary engine.

As far as the experimental group. If you can go the Real World solution and do a do-it-yourself rotary for say $12,000 to $16,000 are you going to pay just $31,000. I am sure it is great stuff but we have to temper our enthusiasm for reality an VALUE / bang for the bucks.


George,
I really wonder what your problem is? You obviously won't want one, but many people will. The Mistral package is well thought out and mounts to a standard Dynafocal mount, so you could do an install on any thing using one without tremendous changes. There is test data shown on the site. It isn't hidden, though you may have to use the site map to locate it. They will sell you a engine NOW with a REAL delivery date. I made mention of this because the comments were made in a thread about Inodyne which may never deliver anything. Mistral isn't doing the please send us a deposit for a product that may never be delivered. Any comment to that end is simply malicious and without foundation. On several of the Rotary based discussion groups they have been posting results of their normally aspirated 190 HP engine tests regularly. They are running dyno tests almost every day and have hundreds of hours on the Arrow. The Jet-A engine may be of more interest to their customers in europe, but it is running. Paul Lamar who runs the Aircraft Rotary Engine Newsletter has visited the factory which is anything but vaporware. The Mistral PSRU is designed for Hyd/CS from the start which is why I'm interested in it. I consider it to be EXCELLENT value for a new product, which is why I may use it in my aircraft. Tracy Crook offers a different type of product and MANY people are interested in both. Tracy offers an even BETTER value it just depends on what you want to do. I know you prefer Lyc George. Most people who read any of your posts probably think you're on their payroll. Great that is your preference, don't expect everyone else to follow suit. BTW Powersports PSRU costs 6-7000 dollars if you can buy one, just for reference. I think the layout was fine and in fact have comunicated repeatedly with the designer of the reduction drive. The Powersport package costs almost the same price as the Mistral package installed. A new Mistral 230 HP engine still costs less than a O-540 from Vans if I was to buy both new. The O-540 on Vans site with his discount is $37,500.00, The IO-540 is $42,000. That is a bare engine without an "install kit." You can and may very well do better, but many pony up for a new engine from Vans. They could do the same for less from Mistral and have to do some development fitting the Radiators and oil cooler, that is the big difference.
Bill Jepson
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rv6ejguy said:
Bill, given much thought to rads and ducting on your 20B installation yet? I'm starting to install my custom built rad and belly scoop now. Impressed with the rad which uses a Visteon type core (can't reveal the source or I will be killed). On my flow bench, it had 1/4 the pressure drop of the commonly used GM/ Harrison evaporator cores so I'm hoping that with my adjustable exit door, the drag penalty will be minimal. I spent hours looking at various under cowl rad setups but space, ducting and or poor flow settled me on the belly scoop. Some flow testing indicated that air from the cowling exit duct would turn the corner into the belly scoop inlet so I had to solve this by fitting a horizontal splitter between the two. Messing up Van's clean design by putting a car engine in it. It will be unique though. :)

I'll be interested to see how Eggenfellner's supercharged 3L Subes perform and cool in the -10 with the cheek mounted rads.
Click to expand...

I have given a great deal of thought on the radiator location on the 10. Send me a private message with your e-mail and I'll send you a layout I've been working on. For everone else's benefit, I plan to use 2 radiators near the firewall on both sides. The possibilities are ducting for a wedge entry with the radiator exhaust exiting near the firewall but the radiator facing almost directly at the rear edge of the engine with the exit being the standard location with a cowl flap. The other possibility is about 180? reversed with a side exit near the bottom of the cowl side. I call this layoout the "gill" exit for obvious reasons. For oil cooler/s I may use a Fluidyne rad/oil combo on both sides or run the rads in series with on smaller to stack with the oil cooler.
Cheers,
Bill Jepson
Rotary10-RV
 
Mistral rotary

These Mistral guys are about an hour from my house down the road in Geneva. If someone is really interested, I could swing down there and take some pictures of what they are up to. I've never visited their shop, so I have no idea what to expect.
 
Negative never said that or that

Rotary10-RV said:
I really wonder what your problem is? You obviously won't want one, but many people will. The Mistral package is well thought out and mounts to a standard Dynafocal mount, so you could do an install on any thing using one without tremendous changes. (OK thats great and never said anything about that, but what about the cooling, exhaust.....)

There is test data shown on the site. It isn't hidden, though you may have to use the site map to locate it. They will sell you a engine NOW with a REAL delivery date. I made mention of this because the comments were made in a thread about Inodyne which may never deliver anything. Mistral isn't doing the please send us a deposit for a product that may never be delivered. Any comment to that end is simply malicious and without foundation. (Now you have to read what I said. I made no comparison between the companies, read it. I did say I did not think they where going to make it in the market. I did say the price is too high and they seemed confused about what market they want to be in. You made that connection and it must be in the back of your mind not mine. As far as dynafocal is the engine the same length as a Lycoming ans will bolt to stock mount for lycoming? If so that is nice.)


On several of the Rotary based discussion groups they have been posting results of their normally aspirated 190 HP engine tests regularly. They are running dyno tests almost every day and have hundreds of hours on the Arrow. The Jet-A engine may be of more interest to their customers in europe, but it is running. Paul Lamar who runs the Aircraft Rotary Engine Newsletter has visited the factory which is anything but vaporware. The Mistral PSRU is designed for Hyd/CS from the start which is why I'm interested in it. I consider it to be EXCELLENT value for a new product, which is why I may use it in my aircraft. (Obviously you are doing your home work and going in eyes wide open. As far as excellent value, I will tha'ts subjective. Their quoted price are with no installation, just engine, right.)



Tracy Crook offers a different type of product and MANY people are interested in both. Tracy offers an even BETTER value it just depends on what you want to do. I know you prefer Lyc George. Most people who read any of your posts probably think you're on their payroll. Great that is your preference, don't expect everyone else to follow suit. (I don't think I once said you must do as I say. In fact I don't really care as long as we are all safe out there and don't hurt someone. Again I said Mazda Rocks!, but I do think Lycomings Rocks more, that's all.)


BTW Powersports PSRU costs 6-7000 dollars if you can buy one, just for reference. I think the layout was fine and in fact have communicated repeatedly with the designer of the reduction drive. The Powersport package costs almost the same price as the Mistral package installed. (yes I did not get into a component to component debate. The power sport has been mounted, installed and flown in several RV-8's with good results, that is all. If Mistral as a better, cheaper reduction drive, great, bring it on. Needless to say a driect drive Lycoming eliminates the need for reduction drives.)


A new Mistral 230 HP engine still costs less than a O-540 from Vans if I was to buy both new. The O-540 on Vans site with his discount is $37,500.00, The IO-540 is $42,000. That is a bare engine without an "install kit." You can and may very well do better, but many pony up for a new engine from Vans. They could do the same for less from Mistral and have to do some development fitting the Radiators and oil cooler, that is the big difference.
Bill Jepson (I saw the one wire frame drawing with radiators and "page under constuction, contact the CEO?". You know again I think you are over sensitive. I never compared the Mistral to a Lycoming, you are getting into it, not me. However to be fair you have to compare your rotary to 260HP. I guess they claim 300 HP for the 3 rotor engine. (300hp at the prop sounds inflated, since the RX8 sports car 20B engine is rated at 250hp at 9000rpm!) The 20B would be a better comparison to a 260hp 540 Lyc. The cost will be way more than the 2 rotor 13B, which is not suitable hp for a RV10. I think if I want to get into a apples and apples comparison any engine "KIT" (rotary, subaru) will not be cheaper than a Lycoming. From the kits I have seen cost is not an advantage, but there you go again bringing up Lycomings? Unless you could go the do-it-yourself route, no one is saying the engine "Kits" are cheaper to buy and install. What is the project cost of a 20B from Mistral? You can price out a Lycoming installation out exactly today. You can't do that with Mistral, but again I did not bring this up. The market will speak.)

(Till they make it, install it, fly it, check it, price it and sell it, its a concept, not a reality. Dynos are great but it is not an airplane. I am not impressed with a few 100 hours in almost 2 years and dyno runs, but that is just me, a problem child.)
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Bill sorry I did not put my nomex flame suit on, OK, boots and gloves on, now typing.

I stand corrected the rotary is a great engine and should be put on all cars, planes, boats, motorcycles and anything that requires an engine, OK. Mazda engines ROCK! OK I was driving RX2's and RX3's in the 70's (really I was). I never said anything negative about the engine, the late Dr. Felix Wankel or anyone. Mazda's are great fun cars to drive. Well you may detect a little a little sarcasm. I am making a point. Every engine has its pros and cons. OK, but that is not the topic.

As far as Power Sport they have or had planes flying, flight tested by somewhat independent sources (Van's aircraft). Those engines came after 15 years or more of development (started by the late Hatch). The part where they have flown is priceless. RWS also has many units out there. Until a engine is flying in a RV with a total Minstral package and tested I will be super cautious and skeptical of claims of better anything. Again every engine has pros and cons. Its hard to overcome basic principles and limitations.

Someone has to not drink the cool aid. Now calm down, what I mean. Well I said I think the Power Sport and RWS (real world solutions) are already on the market (the former a little shaky by others accounts). My realistic comments are I don't think Minstral will sell many at $31,500 dollars (my opinion, hope I am wrong). I also am pretty sure it will not do anything better than all the other 13B's out there. The 20B sounds interesting but that is even further out than the 13B. I will be happy to be proved wrong. I also have noted correctly that they don't seem to know what market they want to pursue, certified or experimental(?). None of this gives me warm fuzzies.

As far as flight test data I did not find it. Their weight chart is an estimate an I think a little optimistic.


I have been flying and building planes for almost 3 decades and love all things that bun gas and make noise. So accuse me working for Lycoming if you will; yes they do Rock; lets just say I am opinionated and have as much right as you to say what I want, as long as it is not personal and thoughtful. I am not wishy washy about it. New engines or new companies have to prove themselves; its too important, lives depend on it. I have stayed on point by the way have not broke into any advertisement for the ROCKING Lycoming!! Woo-Woo, Yea, all right, yahoooo. :D You brought up Lycoming. I don't think we need to attack Lyc's to make something look good. However it is the gold standard for light aircraft.

With that said no hard feelings but lets face facts, and let them speak for themselves. I am eager to see how the new 3-rotor works in the RV-10. It could be a sweet spot? Who knows? Not many have experience with it. I am not negative just realistic. I want Mistral Reduction Hyd/Prop and EFI to be the most rocking thing to hit the airwaves. I am just not going to get excited myself, and I criticize no one for going where no man has gone before. It is important to vent all the pros and cons, and you have done a great job bringing out little know facts for the Pros of this new engine supplier. There are for folks looking into alternative engines who are new the home building. They need to hear both sides.


When I say, "It is my opinion they will not make it to the market", I think that is a bet I would make. You say they are not more than Power Sport. Hey PS is a good product and they are struggling. That is my whole point. It is hard to compete with brand NEW Lyc (clones) for $20K, not withstanding the 540's.

I write as if I was giving a good friend advice. I Sincerely believe what I write and would not invest in a Mistral at this time as I said, until they where flying many many engines. In my opinion that is way off in the future at the speed they are going. We have to temper enthusiasm with facts. If I was buying a Rotary kit it would be Power Sport, or make my own using RWS stuff hands down. The interesting thing about Mistral is that hydraulic constant speed prop reduction drive. May be that will be a cool thing, but I would wait to see what the cost, weight and some service history. Hey it is not a new piece of avionics. This is serious business. If the prop stops, for what ever the reason, is could kill you. Proceed with caution on new technology.

I guess that is my problem, I am super conservative and error in caution. New engines, drives, EFI or what ever have to prove themselves before I will put my butt or a passenger behind it. George
 
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RX-8 is 2 rotor, not three

quote from GMCJETPILOT? "since the RX8 sports car 20B engine is rated at 250hp at 9000rpm!"

Actually the Renesis engine is very much like a 2 rotor 13B.

A 20B with similar treatment might be ~375 HP @ 9000 rpm.
(125HP per rotor)

-mike
 
mlw450802 said:
quote from GMCJETPILOT? "since the RX8 sports car 20B engine is rated at 250hp at 9000rpm!"

Actually the Renesis engine is very much like a 2 rotor 13B.
Click to expand...

the renesis engine IS a 13B. it's a 13B-REW with 250 hp.

mickey, i think we would all love to see some pics and a tour report if you get a chance to go down there!
 
Renesis RX-8 engine

All,
The Renesis engine used in the RX-8 sports car is a 2 rotor. It differs from the earlier RX-7 engine by having all the intake and exhaust functions passing through the side plates. Mazda did this to enable them to run larger ports without overlap problems. Almost all of these changes were done to enable the engine to work better in automotive use. That is to run better at lower RPM. The higher HP is as a result of larger ports and higher RPM operation. The Renesis (stupid name) is redlined at 9k. The rotary will operate at those RPM's easily, but for aircraft use I would prefer to derate the engine somewhat for total reliability. Additionally the Renesis comes in 2 flavors, Manual and Automatic. The manual trans engine has the 6 intake ports and makes 235 approx. HP at 8700 RPM. The automatic engine has 4 intake ports and makes about 200 HP. This is normally aspirated, not turbocharged.
The basis for Mistral's 2 rotor engines is the earlier 13B engine. They will be doing a complete engine, (not Mazda), as this is required for certification tracking. The geometry of the engines, the shape of the housings and offset of the excentric shaft is the same.
The 230 HP Mistral engine is turbocharged, and would make a excellent RV-10 engine. It provides enough power down low and will provide superior power at higher altitudes than a IO-540 Lycoming. (Watch that TAS an altitude) I plan to use a NA 20B 3 rotor, Derated to 250 or so HP. Max RPM will be about 6k in my operation.
Bill Jepson
Rotary10-RV
 
I much prefer facts , thank you

I am confused, but this is where I got my info:

http://cp_www.tripod.com/rotary/pg20.htm


What I gather, 3 rotor engines have been made for a while (Cosmo) and came in at 280 hp to 450 hp for flat out racing engines. The cost of a core is $20,000, bare. I assume the designation was 20B. I don't think I mentioned "Renesis", but did mention the RX8, which has the 2-rotor Renesis 13B? I guess the 13B Renesis is rated at 250hp in the car. If installed in a plane, not at 9000RPM and going thru a reduction drive, the HP at the prop will be? I don't think its 250HP.

The normally aspirated 3 rotor rotary that mistral post has 300Hp is a lot, but like the 13B, I would be surprised if at "normal" rpms and by the time you get to the prop you would have more than 260Hp. I could be wrong, and I am guessing since I don't think there is too much info here.

The 20B turbo seems to be the hot thing, but it will not be cheap or easy to do. Mistral 360-TS is claimed to put out 360hp (at what rpm). HP cost gas there is not free lunch. In the end will it be better than a IO540 or 540 turbo-ed? We will see. On Mistral's site no price is quoted, and installation is so important with a turbo.

Based on the modular feature and from what I know about a 13B, the most HP you can can expect to get at the prop is about 80-90 hp per rotor. (at least non-turbo. Remember you are not running 9000 rpm and you have a reduction dive, which looses some efficiency. So I guess to get the power you are committed to turbos, with more efficiency and yes power. It seems the best way to get the power and efficiency from any auto alternative. With that said there is added cost, complexity and maintenance.

Also Tracy of RWS runs his 13B RV-4 in the 160hp class and does pretty well. Why does he not race in the 180hp ore open class? If he raced in the 180hp RV class, his times would not fair so high in the pack. My point HP quoted is meaningless unless it translate to HP at the prop and airspeed.

With that said the last Power Sport engine kits (the most complete rotary package around: mounts, radiators, cowl....) did fairly well and matched the performance of a 180 Lyc RV (in fly off with Van's RV-8 prototype published in the RVator). However (don't hate me) the rotary did this at the expense of significant greater fuel burn and yes, noise. The good news is the weight was not grossly higher, and not to be over looked the performance did come up to the Lycoming. This is really good and significant. Most of the auto conversions have fallen short of the standard speeds set by Lycoming. My theory is cooling drag is too high. The Power sport with the custom cowl seemed to recover a little cooling drag reduction.

That is why I get all excited about installation. HP means nothing if you have big gap-ping holes in your airframe. Look air-cooled engine cooling drag has been optimized for over 80years and studied and tested on military fighters, NASA and universuty for decases. For any company to be a success in this market they have to offer a complete package, not just the engine.

Egg does well in the complete part, but in my opinion (as an engineer, pilot) it is far from optimal. Nice yes, optimal no. Retrofitting to an airframe that is designed abound an aircooled engine is going to be a compromise unless someone does a blank page design. I could see where you by a kit and build it into the airframe, well before mounting the engine. Cooling tunnels, embedded radiators in the firewall, fuselage? My point is the use of water cooled engines in RV's is in it's infancy. A breakthrough installation has yet to be designed and flown on a RV, but it is getting better all the time. Keep going. When you all figure it out and get the cost down, I will come in and shamelessly copy it.

What ever Power Sport did, it should be copied. I hope they continue to stay in the game or at least their efforts continues by someone. George.
 
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I too liked the professional approach of the Powersport Wankels, especially their redrive development and testing however their fuel flow numbers and ECU development and programming appeared to be inferior to some of the developments by Mistral and RWS if you can believe published numbers. I award high points to Powersport for flying two RV8s down to Van's and doing head to head testing. They have been the only auto engined converters to have had the confidence in their product to do so to date.

I also believe after much flight testing and experimentation that Powersport's radiator setup, despite being cool looking was a relatively high drag solution. I've done much research into this area on our RV6A testbed and detailed examination of WWII radiator installations and believe that a dedicated rad duct offers much lower cooling drag penalties than most currently used setups. Recent flow bench testing shows a massive difference in pressure drop between different heat exchanger types. This is equally important in the cooling drag equation.

The lowest drag solutions are undoubtedly those using scientifically selected heat exchangers in a dedicated and properly shaped duct with the cooling system installation having primary importance in the design. The best historical designs being the DB powered D series FW 190 and TA 152 with ring radiators and the P51 with its cooling system designed into the airframe rather than onto it. Honorable mention goes to the leading edge rad installations in the twin engined DeHavilland Hornet. The Hornet in particular is very impressive with 2070 hp RR Merlin 130-131 engines rated to perform up to 35,000 feet, with the layered coolant, oil and charge air heat exchangers and 485 mph top speed (430 mph cruise!) has exceptionally compact setups. These were built before aluminum furnace brazed heat exchangers that we have today were available. These chaps have forgotten more than we're ever likely to know about liquid cooled aero engines.

Analysis of radiator face area, volume, inlet and exit areas and installed hp of these in particular indicate much higher efficiencies and lower drag than every single liquid cooled experimental aircraft flying today that I have examined except for one Chevy powered Velocity which used a dedicated boundary layer type scoop, modern heat exchanger and exceptionally small face, volume and inlet area.

Unfortunately, it can be difficult to integrate a good radiator installation on an aircraft designed for an air cooled engine from the start. I agree with GMC here, there is much work to be done in this area to arrive at a low drag solution rather than just getting the job done irregardless of the drag penalty.

Certainly low cost has been a factor in experimental aircraft but a couple GM evaporator cores or similar jammmed behind the cheek inlets is far from optimal. That being said, there are other design parameters and considerations that are important. Ease of installation, weight and routing of lines makes this approach attractive for firewall forward bolt ups in one assembly like the Eggenfellner packages.
 
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Thanks, Mick

rv8ch said:
As I promised, I went to see Mistral last week, and did a little 3 article writeup one what I learned. Seems like good stuff to me!
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Thanks Mick, do you have any data on fuel burn/hp besides the 0.45 lb / hp number. That's good and is in fact right up with the Lyc. They did that how? Dual plugs is standard on a 13B. Better intake, dual injector and elctronics sounds interesting. I would like to know how that works. Interesting.

I also like the dynafocal mount, so I assume the crank flange face is right where it would be on a Lyc. Brilliant, awesome idea using existing mounts.

Full up installed weight in an aircraft would be another good number to know.

I think three things are in the way. Cost, must come down. Second is weight control, must be no more than an equivalent Lyc. Third and last, a low drag radiator installation. If they can get it certified and meet the three challenges and make the fuel flow they claim it will be a success. It is a little company right now with a big empty plate to fill, but micro soft and apple where small companies at one time to.

Looks interesting and wish them the best of luck. I really like to see there future 3 rotor engine.
George
 
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Mistral fuel burn

gmcjetpilot said:
Thanks Mick, do you have any data on fuel burn/hp besides the 0.45 lb / hp number.
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Francois gave me this foil, which I just scanned, so I hope he's ok with me posting it. They said that installed engine weight is about the same as with a lycoming 360.



They have some good information on costs, but I'll let them sell the engine. I just wanted provide some impressions from a disinterested third party, since I live close to their facilities.
 
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great write up mickey! thanks for taking the time to visit their facility. it's so nice to have this community set up where we can take advantage of the locale of so many people around the world to give us first hand accounts of companies and interests that some of just can't do at this time. i, for one, really appreciate your visit and info!

thanks. :D
 
Interesting, thanks again

rv8ch said:
Francois gave me this foil, which I just scanned, so I hope he's ok with me posting it. They said that installed engine weight is about the same as with a lycoming 360.
Click to expand...
I won't tell. :D That makes sense. They are very close to the Lyc below 75% power. The real key there is lean of peak Ops. That is the key. I suspect the Lyc data was at recommended best power mixture, which is totally fair. I think LOP for small Lycs can be hit or miss in practical real world application. The point is not that the Rotary is a fuel economy king but at least fuel econ with prudent power and mixture control can get decent fuel econ.

To play devils advocate, on a RV mission flying at low altitudes and high power you can see where the rotary might get the thirsty reputation. Their ignition and intake design may help, but the key is LOP ops. That kind of opens my mind up a little. For the low power high altitude cruise the rotary's fuel econ should be OK/not bad. However, even from their data it's obvious that at high power the rotary gets real thirsty. Again thanks Mick, very interesting. Cheers George
 
gmcjetpilot said:
I won't tell. :D That makes sense. They are very close to the Lyc below 75% power. The real key there is lean of peak Ops. That is the key. I suspect the Lyc data was at recommended best power mixture, which is totally fair. I think LOP for small Lycs can be hit or miss in practical real world application. The point is not that the Rotary is a fuel economy king but at least fuel econ with prudent power and mixture control can get decent fuel econ.

To play devils advocate, on a RV mission flying at low altitudes and high power you can see where the rotary might get the thirsty reputation. Their ignition and intake design may help, but the key is LOP ops. That kind of opens my mind up a little. For the low power high altitude cruise the rotary's fuel econ should be OK/not bad. However, even from their data it's obvious that at high power the rotary gets real thirsty. Again thanks Mick, very interesting. Cheers George
Click to expand...

Additionally intersting George is that the Foil Mickey printed shows the printed Lyc fuel flows at the preformance level that they print. Not casting any aspersions here, Lycoming doesn't publish the flows at higher outputs. I'm very interested in fuel flows at high outputs. The rotary is more rather than less efficient at higher HP levels. Tracy Crook has found that the rotary is very tolerant of LOP operation. He comments that he takes off LOP in his RV, as he is, "really cheap" by his own admission! The rotary's combustion chamber which contributes to higher fuel consumption numbers also seems to tolerate the LOP operation well. I guess this is a give some get some deal. Many thanks to Mickey for his tour info.

Bill
 
No aspersions, but wishing so does not make it so

Rotary10-RV said:
Additionally interesting George is that the Foil Mickey printed shows the printed Lyc fuel flows at the performance level that they print. Not casting any aspersions here, Lycoming doesn't publish the flows at higher outputs. I'm very interested in fuel flows at high outputs. The rotary is more rather than less efficient at higher HP levels. Tracy Crook has found that the rotary is very tolerant of LOP operation. He comments that he takes off LOP in his RV, as he is, "really cheap" by his own admission! The rotary's combustion chamber which contributes to higher fuel consumption numbers also seems to tolerate the LOP operation well. I guess this is a give some get some deal. Many thanks to Mickey for his tour info.

Bill
Click to expand...
No aspersions taken but it is kind of crazy to run the Lyc above 75% power anyway. The key to economy is get to the magic 75% and lean the crap out of it. No secret. However with that said, it does not matter if Lyc publishes FF at high output (which they do if you own official Lyc manuals with a nomagram), Mistral did publish Lyc numbers (actual or Lycoming numbers?) and they are better than the Rotary at high power.

Physics of a long skinny combustion chamber (Wankel) is such that it is inefficent. No aspersions just facts and physical limitation. I know people want it to be sooooo not true, but Wankel's are not fuel efficient, I know. Now with that said if you go right to altitude, and lean the crap out of your Mazda 13B, have good ignition, tuned intake & exhaust, you can do OK, not super great, OK. Down low on the "pipes" you are burning lots of gas, like any engine, but the Mazda does get more thirsty then pistons at high power. Wishing it was not true does not make is so. It is just the way it is. If you know that and adjust your operational techniques you can minimize the fuel penalty.


I agree with Tracy you can go LOP and believe the Mazda is tolerant of LOP, because there are only two rotors, firing more so power pulse unevenness will be less noticeable than a reciprocating engine. With 4 pistons, one pulse per two crank turns, if just one stumbles, it makes a difference. Tracy has my respect and is a straight shooter, but he is a true he is a true Disciple and believer. He is like a mad scientist in the best possible sense of the word. Also he actually flys the crap out of his own parts. Hat's off. Now can the average pilot/builder get the same LOP operation Tracy does. Yes but it will be work, by operational technique and engine tuning/tinkering. Same with Lycoming.


Depending how you fly the promised fuel economy of a Wankel may be less than realistic. Some people say they can LOP a Lycoming O320 with a carb! I find that hard to believe. A fuel injected Lyc, the bigger the better, 200hp, 260 hp, yes you can get LOP. Again its effort and you need to balance the injectors and have an engine monitor. Most homebuilders are more likely to do this. Lycoming says it is not practical on small Lycs because the GA population is not as crazy as we are, but for those willing to make the effort and tinker and fine tune, it is possible. The same applies to the Mazda or Subaru.


TURBO and SUPERCHARGING
My real feeling is with a Subaru or Mazda the best efficiency and only way to go is turbo charging (or supercharging with the Subaru). If Mazda offers a turbo and Subaru offers a super charger don't you think there is a reason? They know something. What works in a car is a real benifit in a plane.

Every engine theorist knows to best way to increase efficiency is increase compression. A turbo does that. Most of the time we are normalizing at altitude, but that is a boost, since the delta of induction to exhaust (ambient) is greater, thus a great pressure ratio.

Now a Lycoming can be turbo-ed and gain high altitude efficiency, but I think the water cooled engine has a turbo advantage. Water cooled engines are more detonation resistant and have better internal heat transfer. Air cooled Lycs can be turboed but you now need an inter-cooler and a bigger oil cooler to get rid of the extra heat of induction air compression. With water cooling you already can cool the turbo easily.

However the water cooling may be better for internal engine heat transfer it sucks for airframe cooling drag. Placing a radiators is the Achilles heal of water cooled engine installation in airplanes. I have only seen workarounds and make it works, but nothing elegant. Look at a P-51 and get back to me.

Air cooled engines in airframes designed for air-cooling are super efficient from a cooling DRAG stand point. Yes they are not as good for heat transfer of the internals but we have had 80 years of perfecting air cooled aircraft engines. The military, NASA and the who who's of 20th century industry has worked the problems of air cooled aircraft engines and installations. When some one makes an airframe just for water cooling than you will see better performance numbers. I know the Thunder Mustang set some records with a Falcon V12 (N2O) in a P-51 clone. That is my point. The Thunder Mustang airframe was made for water cooling. The RV is not.

Never the less if I had a Mazda or Subaru it would be Turboed or Supercharged. I would not mount the heat exchangers in the stock Van's cowl original air inlets, like Eggy does. That works but its draggy. Wishing it was not does not make it so. It works. It looks OK but these are inlets for AIR COOLED ENGINE. They way powersport (rotary engine kit) did it is better with the single chin scoop. It could likely still be even better, but it is a great start.

It is possible you will never get H2O engine airframe drag down to an equivalent air cooled engine. Well at least that is true unless some one comes up with some break thru exchangers, skin cooling or some cooling tunnel integral to the airframe. A stock RV airframe will not hack it. Again wish it was not so, but its true. That big ass radiator is a bummer for you water cooled guys, and usually it is an after thought in the installation.




COOL ENGINE: Echotec $4500.00 NEW, 205 HP
http://www.crateenginedepot.com/store/Ecotec-Crate-Engine-20L-Supercharged-12499466-P826C2.aspx

Here is a hop up book: http://greenwoodchevy.com/Merchan...58646&Category_Code=BV_CC&Store_Code=GCGPPEDH

This might be cool for a RV-9. Yes it is 205hp, but people forget the reduction drive waste hp. Also you are not going to be winding it up 5,600 rpm. I think 160 hp at the prop flange is a realistic goal. Also with the narrow engine you can make a skinny cowl, like a P-51. While you are at it, why not a belly scoop, like a P-51? $4500 for a NEW engine. Not bad. Add an A/C compressor and have an AC RV! (kidding)

The EchoTec has a supercharger, again compression is the key, and water cooled engines are more tolerant to higher compression or "compressed induction" than air cooled engines. I would exploit the water cooling for all she is worth and turbo or supercharge. It will not help much down at low altitudes (fuel economy wise), but high altitude performance will be good; If and that is a big If, you install the radiator'(s) with min cooling drag.


COOLING DRAG
Min cooling drag is taking 200 mph dynamic air pressure, slowing it down, passing it thru the cooling core, expanding the air again and exiting the air parallel to the free air stream with min internal loss. Easier said than done. That is why the P-51 was so awesome, but to be real, it did not hurt that it had 2000 hp either.

Again I wish Mistral all the luck in the world and think their 3-rotor turbo engine might be hit, BUT they must keep cost down, weight down and have a complete low drag package. That cowl abomination of their Piper test bed Arrow is not pretty or efficient. Wishing it was not so will not make it so. Still waiting for Arrow miles per gal VS. speed numbers. Dyno numbers mean nothing unless its in the plane.

I am looking forward to all the new Rotary engine installations to come, Mistral, homemade or other. Keep inventing but it is a big puzzle and it all has to fit. Right know weight and cooling drag are your enemies. (Not me)


George
 
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Even liquid cooled turbo/ supercharged engines require additional oil cooling and intercoolers and this unfortunately creates more drag. You just can't escape that the compressor adds heat to the charge and this adds more heat to the engine. I routinely see compressor discharge temps near 100C in a climb above 10-12,000 feet. Eggenfellner had to add an intercooler to his supercharged engines after finding out that induction air was getting too hot.

I think you could do a decent rad layout on a taildragger RV without the nose gear structure in the way. This would allow a pretty good belly scoop design if you moved the exhausts outboard. Tri-gear RVs are that much harder to do properly. I'm working on my -10 rad/ belly scoop setup now. I've got over 40 hours into it now and it's still a ways off. Internal drag should be pretty low but this will be offset by the external drag of a pretty big scoop to house the custom rad. Won't know until it flies how this setup performs. Fingers crossed.

On the Wankel note, John Slade will soon have his new TO4 turbo installed on his high compression 13B Cozy. He plans to do extensive speed/ fuel flow tests and compare the numbers to several Lyco powered airframes. This should enlighten all of us. John is a straight shooter and is using Tracy's EFI so he can easily tune LOP in cruise.
 
Waiting eagerly

rv6ejguy said:
On the Wankel note, John Slade will soon have his new TO4 turbo installed on his high compression 13B Cozy. He plans to do extensive speed/ fuel flow tests and compare the numbers to several Lyco powered airframes. This should enlighten all of us. John is a straight shooter and is using Tracy's EFI so he can easily tune LOP in cruise.
Click to expand...
Hummmm compressed air is hot, water cooling does not help the air. I assumed that the engine would tolerate the pre-heated charge, but than hot air is not as dense. That creates diminishing return on power; combined with less available cooling air as you fly higher (less molecules) you are toasting the engine. I did not know the Eggy needed to add inter-cooling to the supercharger version. That's too bad. Its a hassle to install an inter-cooler as you say, but does add power. The one turbo Lyc RV-8 floating around is very nicely done has an inter-cooler, but its a nightmare of hoses.

The RV-10 sounds like a winner rv6ejguy. What ever drag your belly scoop might add, you should be taking drag from the stock cowl by removing the stock inlets.

Hi comp rotor and turbo (don't know what a TO4 is, but guess "T "stands for Terminator). Sounds powerful, especially at altitude. DO you think that will be reliable? AND does it require an inter-cooler? The pusher guys are real clever in reducing cooling drag of their air-cooled power plants. I think the pusher configuration plus fiberglass construction lends itself to modifying and making a good radiator installation. I think it will be cool (no pun intended). There was a fairly exotic Subaru pusher (EZ) in the EAA mag a few years ago. It used a long carbon fiber prop extension.

George
 
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Unfortunately I still need the stock RV10 inlets for the intercoolers, oil cooler and compressor inlets so I'll still have higher drag than an IO-540 installation. I don't expect to be able to do much better until I'm over 10,000 feet.

The Cozy has already flown with a stock Mazda turbo and has terminated a couple due to over speed conditions at altitude. I helped John in matching a proper Garrett TO4 unit. He has always had an intercooler on it. Yes, the pusher guys can probably get a better rad/ intercooler setup due to packaging in these designs. They are working pretty well with NACA ducts feeding them however the total cooling drag equation is still not answred at this time. John's testing will be very enlightening.

There are a few other turbo 13Bs flying. Will it last? Well that hasn't been proven in the long term yet. At least they are easy and cheap to rebuild.

The pusher guys are very innovative with engines, props, ducting compared to us tin bashers. There are many auto engined ones flying. It is vey interesting to follow their developments, triumphs and failures.

The Eaton blower engines discovered the high charge temps above 8000 feet or so. The adiabatic efficiency of these is inferior to a good turbo so this is no surprise.

Interesting article on Bruce Bohannon's altitude record Tiger RVXXX in July/ Aug. '05 EAT mag. 400F compressor discharge temp at 47,000 feet, less than 100F out of the massive intercooler mounted behind the firewall, CHT 525F, Oil 260F, EGT 1800F. Someone screwed that Lyco together well! :cool: :eek:
 
One things to consider

Newbie here, trying to talk myself into building an RV. Being an experimental kinda guy, I've been looking hard at alternative engines. The Mistral seems to be the only realistic AIRCRAFT engine alternative out there.

If I were to do a Lyc or a clone, I'd want the FADEC and electronic engine monitoring. That stuff just turns me on. Since I'm planning on those gadgets anyway, the Mistral package looks more attractive. It includes its own FADEC, with dual-redundent "everything", along with an electronic monitor for the panel. It also includes the starter and alternator.

Compare apples to apples, and the price difference between a 180 hp Lyc clone with FADEC and monitor, compared to the 230 hp Mistral turbo, is very small. You end up with an extra 50 hp for $1000 or so. Not a bad deal, if you ask me.

If you want a Plain Jane Lycoming with carb and magnetos then all bets are off, of course. But the Mistral is a relative bargain if you want all the goodies.

It'll be a few years before I make any decisions, and things will change radically by then. But if I were doing it TODAY, I'd get the Mistral. Hopefully the kerosene version will hit the market by then. That'd be just the ticket!

p.s. A belly scoop for the radiator would like like a P51. Draggy, certainly, but tres chic.

Has anyone considered an automotive-type electric cooling fan (or fans) mounted to the radiator? Many of them are very thin and should fit in a tight installation. They draw a lot of amps, of course.
 
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The belly mounted rad concept if properly executed offers lower drag than cowling mounted solutions which generally suffer from poor pressure recovery due to short inlet geometry and high internal drag due to packaging concerns within the cowling. Oblique mounted rads suffer from high pressure loss due to the air having to turn 180 degrees. Do you see either of these solutions on any WW2 liquid cooled aircraft? Every successful design uses pod mounted rads.

Fans create tremendous flow blockage and drag in flight so these are not a great idea if low drag is a concern.
 
Engine Failures.........

Rotary10-RV said:
Powersport's site is back up though they continue to be hanging on by their fingernails. The plane (Jim Clark's) that went down had an electrical failure not engine. Sad as it is a well concieved package.
Bill Jepson
Click to expand...

Bill,

The electrical dependancy of all current automotive style conversions is a major shortcoming when installed in aircraft (IMHO). To me, (and the FAA) if your fuel and ignition system is dependent on your electrical system for it's operation, it is not suitable for use in an aircraft. I have been let down time and again by the 50 cent diodes in alternators, and the batteries they are tied to.

It seems to be common thinking amongst the alternative engine crowd the when systems of an alternative engine cause an airplane to go down, it didn't really experience an engine failure. Egg will tell you that he didn't really have
an engine failure, although the results are the same. Egg will also tell you that Ray Doerr didn't have an engine failure, it was a fuel system failure that caused the loss of his -9. Dave Leonard will tell you that it is not the rotary's fault that he landed on a road when he ran out of coolant.

Purpose-built aircraft engines have many advantages over automotive technology retrofitted to aircraft. I have a hard time imagining why anybody would trade the reliability, smoothness and simplicity of a certificated Lycoming for the unknowns of a prototype car engine. What are your reasons Bill?

John
 
If I understand correctly, the Mistral has totally separate redundent fuel injection, ignition and engine controls. I would imagine they could be run off separate electrical busses.

I don't know if the Aerosance has that level of redundency. That would be my first question before pulling the trigger on any sort of FADEC system, Mistral or otherwise. I want complete redundency, as well as a "limp home" setup in case BOTH systems fail. The Mistral seems to have that covered.

I agree that an automotive system is a bit iffy. If your engine conks out in your car, you call AAA. The stakes are a wee bit higher in an airplane. Especially one that has the sink rate of an anvil. (Well, okay, not an ANVIL, exactly. Maybe a brick. A lightweight brick.)
 
Redundancy

If Mistral has a mechanical high pressure fuel pump and two independently driven alternators with separate batteries, it might approach the redundant capabilities of the 70 year old Lycoming.

Fadecs are connected to whatever standard of electrical system you are comfortable with. I see people installing a backup alternator on the vacuum pump pad. Probably a good idea, if you are putting the electrical system in charge of all engine functions.

John
 
I believe they have two independent electric fuel pumps. The spare alternator is a good idea, though. I hadn't thought of that.
 
Reliability

Are there any statistics on lycoming/aviation engine reliablity? Just curious.
 
Reliability

Mickey,

In production airplanes, maintained by trained and licensed professionals, I believe the accident rate attributed to mechanical failure is about 4%.

In experimentals, where guys can't find their fuel screens, or say, hook up their batteries backwards, the accident rate is considerably higher. :)

John
 
Correct me if I'm wrong, but I think all FADEC equipped Lyco/ Conti in cert aircraft have twin alternators and twin CPUs.

I'd read somewhere years ago where the catastophic failure rate of Lyco piston engines was about 1 in 11,000 flight hours. Can't be sure of the source or how the data was complied or arrived at. I assume things like carb ice, blown jugs etc. have caused forced landings at a more frequent rate than that.

I know at the flight school where I rented at a few years back had 3 forced landings on a fleet of 5 aircraft within 2 years. The 172s averaged about 1000 hours per year each. One Tiger and one Cougar flew a bit less and had no incidents. One carb ice last fall, one blown jug this spring and a dropped valve a couple years ago. The carb ice one wrote the aircraft off. The other 2 limped to a safe landing. Nobody hurt thankfully. Another Comanche two years ago had a rod come out through the side two years ago and the aircraft was severely damaged in the forced landing. It does happen sometimes.

I've talked to many pilots who have suffered failures in long flying careers and talked to many others who have not. Interestingly I talked to several high time pilots (15,000+ hours) who never had a piston engine fail but had suffered one or two in turbine powered aircraft. Luck of the draw to a large degree. It's a good idea to practice forced landings no matter what you fly!
 
Fadec

Hard for me to know what the configuration is of (all) Fadec installations, as I was refering to experimental installs only.

Speaking of reliability, are you the guy that deadsticked the turbo Subaru(professionally, I might add) into the field in Canada?

John
 
Yukon said:
Hard for me to know what the configuration is of (all) Fadec installations, as I was refering to experimental installs only.

Speaking of reliability, are you the guy that deadsticked the turbo Subaru(professionally, I might add) into the field in Canada?

John
Click to expand...

Yep. That's me. Alternator failure. ND copy. Now have real ND alternator, second battery with separate buss and aural warning for low voltage. I learned the hard way. As we like to say in the auto engined world, the engines are very reliable it's the systems that cause most of the forced landings. Oh well, I'll never go down to carb icing at least.
:)

Taught me a valuable lesson early in my flying career. Be current in emergency procedures. Fortunately I was but it's still a shock when it happens for real. RVs with dead engines don't glide as well as most people think. :eek:
 
Your RV-10

RV6ejguy,

I've read your website cover to cover. You are quite a talented guy! Lot's of testing and innovation went into your installation! You have way more patience that I do!

Now comes the question.........what engine are you going to install in your RV-10????

John
 
Yukon said:
RV6ejguy,

I've read your website cover to cover. You are quite a talented guy! Lot's of testing and innovation went into your installation! You have way more patience that I do!

Now comes the question.........what engine are you going to install in your RV-10????

John
Click to expand...
RV6ejguy, do you think you could post your website link here. I would love to check it out.
 
The new RV10 will be fitted with a twin turbo, six cylinder Subaru EG33, turning an MT C/S prop through a Marcotte M-300 redrive. I haven't experienced enough abuse yet to drop $40K on a new Lyco. I cheat by building QB airframes so that extra time saved can be spent on the engine installation, test flying and modifications! :)
 
Just a suggestion......

rv6ejguy said:
The new RV10 will be fitted with a twin turbo, six cylinder Subaru EG33, turning an MT C/S prop through a Marcotte M-300 redrive. I haven't experienced enough abuse yet to drop $40K on a new Lyco. I cheat by building QB airframes so that extra time saved can be spent on the engine installation, test flying and modifications! :)
Click to expand...

I just bought a 440 hr Lycoming 0-235, mfg in 2000, for 10K. That's less than half of new, off a hurricane damaged airplane (minor wing damage).
You could easily do the same with an IO-540. With an MT 3 blade, you would have a very smooth and reliable powerplant that would have no developemental issues or risks.

If you grow weary of too much trouble-free and low-stress flying, you could always indulge yourself with an intercooled turbo install, or a fadec with dual lighspeed ignitions and a Ryton sump........or............ :)

John
 
Yukon said:
I just bought a 440 hr Lycoming 0-235, mfg in 2000, for 10K. That's less than half of new, off a hurricane damaged airplane (minor wing damage).
You could easily do the same with an IO-540. With an MT 3 blade, you would have a very smooth and reliable powerplant that would have no developemental issues or risks.

If you grow weary of too much trouble-free and low-stress flying, you could always indulge yourself with an intercooled turbo install, or a fadec with dual lighspeed ignitions and a Ryton sump........or............ :)

John
Click to expand...

Now that would take all the fun out of it wouldn't it? Some of us just want something different. Coming from the auto engine building world, I'm not sure the word "smooth" and Lycoming belong in the same sentence. ;) :)

Too far along to go back now with money spent on the prop, engine, redrive, rad and 60 hours into the rad scoop. I'm committed or should be, one of the two.
 
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Radiator Scoop

I understand. No, really I do.

You might not remember, but right after your deadstick I emailed you and made the suggestion that you experiment with a belly mounted radiator like the P-51. Now you can blame me!

John
 
Yukon said:
Bill,

The electrical dependancy of all current automotive style conversions is a major shortcoming when installed in aircraft (IMHO). To me, (and the FAA) if your fuel and ignition system is dependent on your electrical system for it's operation, it is not suitable for use in an aircraft. I have been let down time and again by the 50 cent diodes in alternators, and the batteries they are tied to.

It seems to be common thinking amongst the alternative engine crowd the when systems of an alternative engine cause an airplane to go down, it didn't really experience an engine failure. Egg will tell you that he didn't really have
an engine failure, although the results are the same. Egg will also tell you that Ray Doerr didn't have an engine failure, it was a fuel system failure that caused the loss of his -9. Dave Leonard will tell you that it is not the rotary's fault that he landed on a road when he ran out of coolant.

Purpose-built aircraft engines have many advantages over automotive technology retrofitted to aircraft. I have a hard time imagining why anybody would trade the reliability, smoothness and simplicity of a certificated Lycoming for the unknowns of a prototype car engine. What are your reasons Bill?

John
Click to expand...

John,
Let's separate the item in question (the Powersport package) and the question as to MY reasons. The powersport engine and PSRU ARE well engineered. The electrical system of the aircraft in question was not. As you mentioned batteries and alternators can fail. Anyone planning an all electrical system should have a switchable backup battery to enable a short flight to saftey. There are several systems available over the counter. As was mentioned in a previous post MISTRAL's EMS has full and separate redundancy. The engine is being certified, full FAA certification to allow STC replacement of a Lycoming should a customer want it.
As to my reasons? Am I an inferior human if I don't happen to love 50 year old tech? The rotary is an inherently smoother engine producing power in a small package. Mistral has already posted better than Lycoming fuel consumption figures using the rotaries ability to run far lean-of-peak. YADA,YADA,YADA... (Insert your favorite reason here.) I simply like the technology of the rotary, and as a mechanical engineer I enjoy experimentation. I am not a brand loyalist nor even a rotary loyalist, though I do like them. My interests are to engineer a different and hopefully superior package, although I will be perfectly happy if my system is simply equivilent to a IO-540. I am totally realilistic about the pitfalls possible in my choice. It is however, MY choice, and therefore I must do the job well to prevent failures. You need never fly in my aircraft even if I'm totally successful in every aspect. I won't produce Lyc failures to try to bolster my cause because everything can usually be shown to fail occasionally. Cranks, valves, mags, connecting rods, valve springs, pistons, and yes even rotary tip seals can fail. If I can produce a better system people might even want to BUY them from me. I would consider that a super-win, making my hobbies pay for themselves. Selling the system is NOT my motivation though, making myself happy with what I can produce IS.
Best of luck with your choice, I wish all pilots well.
Bill Jepson A.K.A. Rotary10-RV
 
Yukon said:
If Mistral has a mechanical high pressure fuel pump and two independently driven alternators with separate batteries, it might approach the redundant capabilities of the 70 year old Lycoming.

Fadecs are connected to whatever standard of electrical system you are comfortable with. I see people installing a backup alternator on the vacuum pump pad. Probably a good idea, if you are putting the electrical system in charge of all engine functions.

John
Click to expand...

They do have the ability to run 2 independent alt's. They are certifing the engine. They have 2 electrical fuel pumps, like the boost pumps used in almost ANY low-wing Lycoming install. They don't need the mechanical fuel pump. If you wish to fly behind a Lycoming please do. Mistral doesn't demand you buy their product. The fact that they aren't your first choice also doesn't mean that they won't sell either. Many pilots also like brand "C" as well. They might say anybody that puts the camshaft on the top of the engine is crazy to justify their choice. Different strokes...

Bill Jepson
 
Experimentation

Rotary10-RV said:
John,
Let's separate the item in question (the Powersport package) and the question as to MY reasons. The powersport engine and PSRU ARE well engineered. The electrical system of the aircraft in question was not. As you mentioned batteries and alternators can fail. Anyone planning an all electrical system should have a switchable backup battery to enable a short flight to saftey. There are several systems available over the counter. As was mentioned in a previous post MISTRAL's EMS has full and separate redundancy. The engine is being certified, full FAA certification to allow STC replacement of a Lycoming should a customer want it.
As to my reasons? Am I an inferior human if I don't happen to love 50 year old tech? The rotary is an inherently smoother engine producing power in a small package. Mistral has already posted better than Lycoming fuel consumption figures using the rotaries ability to run far lean-of-peak. YADA,YADA,YADA... (Insert your favorite reason here.) I simply like the technology of the rotary, and as a mechanical engineer I enjoy experimentation. I am not a brand loyalist nor even a rotary loyalist, though I do like them. My interests are to engineer a different and hopefully superior package, although I will be perfectly happy if my system is simply equivilent to a IO-540. I am totally realilistic about the pitfalls possible in my choice. It is however, MY choice, and therefore I must do the job well to prevent failures. You need never fly in my aircraft even if I'm totally successful in every aspect. I won't produce Lyc failures to try to bolster my cause because everything can usually be shown to fail occasionally. Cranks, valves, mags, connecting rods, valve springs, pistons, and yes even rotary tip seals can fail. If I can produce a better system people might even want to BUY them from me. I would consider that a super-win, making my hobbies pay for themselves. Selling the system is NOT my motivation though, making myself happy with what I can produce IS.
Best of luck with your choice, I wish all pilots well.
Bill Jepson A.K.A. Rotary10-RV
Click to expand...

Bill,
I think I understand what you are saying, and if you will have dual independent electrical generation and ignition systems, I think your risks will be minimal. I am highly skeptical though of the fuel consumption claims. The recent fly-off at Van's showed the Rotary to be at least 25% more thirsty than the Lycoming.

You know Bill, I spend so much time in my garage assembling what seems to
be the safest and most efficient airplane mated to the simplist and most reliable powerplant, I loose sight of the other possible goals of builders. I forget that my goal of simple, carefree flight is not shared by all.

Experimention is a valid aspect of our sport, and if you have the engineering expertise and a stomach for the risk, I think it's great that you push the envelope. I wish you the best of luck!

John
 
One reason for my "experimental" mindset is a total lack of experience. I'm taking flying lessons specifically to justify building a kitplane. I'm learning EVERYTHING from the get-go. Therefore, I have no built-in biases either for or against any particular engine. But I also have to be cautious not to jump on any bandwagons based on what a web site has to say. (*cough* INNODYN *cough* *cough*......)

Right now, the frontrunners are a Lycoming clone and the Mistral rotary. I think the rotary's fuel economy will end up being the biggest sticking point. I don't doubt that an electronically-controlled Mistral will compare well with a carb-and-mag Lycoming, but when you add FADEC to the Lycoming I think all bets are off. At the end of the day, all other things being equal, you simply cannot get the same fuel economy from a Wankel engine as you can from a piston engine. If Mazda can't do it with all their R&D money and decades of experience, I don't see Mistral pulling it off. The laws of physics are absolute, no matter how much you spend. I am, however, willing to give up a little fuel economy for a "turbine-like" engine that is happy to burn cheap Mogas. That's why Mistral is on the short list.

Whatever I buy, I like the idea of a single-lever FADEC system or equivalent. This is where inexperience comes into play. Fooling with all those pinball game plungers on the panel doesn't turn me on. I'm a child of the video game era. I'm a lot more comfortable around electronicized engines than I am with carbs and magnetos. I understand WHY traditional Lycs and Continentals are the way they are, and I have no argument with people who like them. No need to convince me. But that's just not the way I roll, I guess. I like the "looking out the window" aspect of flying, not the fiddling and fussing aspect. As long as there is complete redundency, I'd much rather have computers running the show. They're far better at it than I could ever be. I want to set it, forget it and eat some Fritos.
 
Bitsko said:
<snip>

Right now, the frontrunners are a Lycoming clone and the Mistral rotary. I think the rotary's fuel economy will end up being the biggest sticking point. I don't doubt that an electronically-controlled Mistral will compare well with a carb-and-mag Lycoming, but when you add FADEC to the Lycoming I think all bets are off. At the end of the day, all other things being equal, you simply cannot get the same fuel economy from a Wankel engine as you can from a piston engine. If Mazda can't do it with all their R&D money and decades of experience, I don't see Mistral pulling it off. The laws of physics are absolute, no matter how much you spend. I am, however, willing to give up a little fuel economy for a "turbine-like" engine that is happy to burn cheap Mogas. That's why Mistral is on the short list.
<snip>
Click to expand...

Bitsko,
Don't worry terribly about rotary fuel burn. Several reasons why, 1) Mazda must set up the car engines for a very wide dynamic range. Almost all mods done to recent 13B and Renesis engines are to make the engine torque available at low RPM. We don't need low RPM except for idle. Lean of peak operations have proven to be excellent on the rotary. We're not talking 50? here either. Tracy Crook has been regularly running almost 200?F lean of peak! Most piston engines won't even run there, or are very rough. Mazda couldn't run that lean in a car due to Nitrous oxide emmissions. Mistral has shown O-360 or better levels comparing their N/A 190 HP version.
Lastly, the fuel burns shown in the Sport Avation article are pure BS. The article was posted first in the RVator newsletter, after which several items were posted about the test methods. The test was set-up at the Lyc's best cruise RPM. There wasn't time enough to find the rotaries best fuel burn RPM. Since Van is a Lyc engine sales outlet, have a Van's employee write the article smacks of conflict of interest to me.
My opinion only,
Bill Jepson
 
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