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CG range of Evo wings?

lufthans.nl

lufthans.nl

Active Member
Hi,

Very new to this forum, and I'll introduce myself in the proper thread later. For now, I've got a question that no amount of Googling seems to provide an answer to:

One reads about how the F1 Evo wing has a reduced CG range when compared to the Hershey bar wings. But nobody seems to know what the actual CG range of this plane is!

Anyone here knows?

(There's this project forming in the back of my mind, trying to tick off one question at a time)

Thanks!!

Hans
 
This is also what I'm making of it. Seems to contradict most things that have been writting about the Evo wing... Most articles go on about how the center of pressure is further forward than the 23000 series wing that is in use on most of the RV series, and how the allowable CG range of the Evo wing is less.

Isn't the tail larger as well? Could that be the reason?

Hans
 
Not sure about the "center of pressure", but the initial CG point of the EVO wing is further aft than the hersey bar wing and thus requires movement of the battery forward on an EVO. The tail feathers are the same on both.

You might have better luck if you emailed Mark directly with your questions at [email protected].
 
I have owned and flown both an EVO and Sportwing Rocket....

The EVO CG range is not the problem, the issue is that the empty weight CG of most EVO airplanes is quite a bit farther aft than most sport wing airplanes.... The EVO could stand to be a bit more forward and the sport wing a bit farther aft....

The reason is that the EVO wing is significantly heavier than the sportwing....

My EVO (Ole '84) is perfectly balanced when solo with about 100-150# of rearseat/baggage combo with half tanks.... With 200 pounds in back, when the fuel gets low, it gets a little sporty and rides hard in turbulence.

With 220# in back, I try to stay in the top half of the fuel tanks and I go slow in the bumps....

For my mission, mostly solo and long X/C flights, the EVO is perfect..... The high altitude performance is incredible, 200 KTAS at FL180 on 10GPH....

If you never plan to go above 10K then the sport wing is probably a better deal... lighter airplanes almost always are......

Tailwinds,
Doug Rozendaal
 
Thanks Doug!

I didn't know that the Evo wing was heavier! Do you have any idea how much difference there is? And why?

While I seldomly fly at anything over 10,000 ft (and in fact never have been over 11,000 for lack of oxygen), there is no denying that the Evo wing has more sex-appeal than the standard wing.

Hmmm.... tough one... I guess it all boils down to the question of weight - how much difference?

Thanks!

Hans
 
200 KTAS at 10 gph is VERY impressive, by the way.

Imagine how that plane would perform with a turbocharged Subaru engine in it.

What's the Vne of both models again? ;)
 
Vne is 240 KTS.

EVO wings weight 65 lbs more than the standard wings.

All of which is irrelevant since you can't get the EVO wings anymore.

A turbo Subaru would probably ruin the performance of the F1 EVO due to the added weight and complexity.
 
Hmmm, a properly done EJ-25 turbo conversion would weigh considerably less than the IO-540 while putting out more power (especially at altitude). But yes, I'll grand you the complexity. I'm up to my neck in ECU wiring on my 5th Subaru project, so I should know. Mission this time: keep it simple.

But let's not get into a pissing contest on engines. There is a lot to be said for simple, while the Subaru has its merits too. Pity there are no real good off-the-shelve Subaru conversions out there. Also pity that in order to do it right, one needs to make a lot of changes to an airframe. Putting radiators up front just isn't going to cut it. Eggenfellner has proved that for us. The fuel system really needs a header tank, and the wiring should be more extensive than on a Lyc too. But when you get everything right these engines ROCK!!

Thanks for the weight figures on the wing.

Hans
 
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No pissing contest here, but you made my point. Because of the CG shift with the EVO wings, you NEED the weight up front. Less weight is bad and result in moving ballast around to get it right. The airframe was designed for the Lyc. Switching up starts a cascade of changes that usually result in a sub-standand airplane from the original design. Now you have to move the engine farther forward, change the cowl, etc.

I have no problem with the Subie crowd. I wish them all the best. It's just not for me. BTW, I've NEVER seen an RV modified for a Subie and thought it looked better than the standard RV. Hence my conclusion that a Subie would probably ruin the F1 EVO. I consider it the best, most sexy looking airplane that you can build.
 
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f1rocket said:
Hence my conclusion that a Subie would probably ruin the F1 EVO. I consider it the best, most sexy looking airplane that you can build.
Click to expand...

The sound of a Subie wouldn't help the F1 EVO either. It puts out a high pitched screeching scream at high RPM, that would make one believe there is a real rocket up there. But then the plane is never as fast as the sound implies..

IMO, the Sube needs a serious muffler.

L.Adamson
 
f1rocket said:
No pissing contest here, but you made my point. Because of the CG shift with the EVO wings, you NEED the weight up front. Less weight is bad and result in moving ballast around to get it right. The airframe was designed for the Lyc. Switching up starts a cascade of changes that usually result in a sub-standand airplane from the original design. Now you have to move the engine farther forward, change the cowl, etc.

I have no problem with the Subie crowd. I wish them all the best. It's just not for me. BTW, I've NEVER seen an RV modified for a Subie and thought it looked better than the standard RV. Hence my conclusion that a Subie would probably ruin the F1 EVO. I consider it the best, most sexy looking airplane that you can build.
Click to expand...

I see your point, and I agree with you on many Subie RV's not looking better. My Jodel has a nose that is about a foot longer than stock, and I got many positive remarks about it, but how it would look on a Rocket? I agree it would be hard to beat the looks of the Lyc powered one...

But.... on the other hand.. long, narrow nose, radiator under the fuselage, just aft of the trailing edge of the wing. The shape of that tailfin and rudder. Tapered wings. That's crying out for invasion stripes and nose art, isn't it? ;)

Shedding 80 lbs of weight isn't a bad thing either, nor is having the higher power levels available at altitude because of turbocharging...

I guess I'll just have to do another extensive W&B spreadsheet to see where the propeller would eventually end up and take things from there...

Thanks for your comments. They are most valuable...

Hans
 
L.Adamson said:
IMO, the Sube needs a serious muffler.

L.Adamson
Click to expand...

Fully agree. And so do the authoroties over here in Europe.

I've got two mufflers in series on my NSI - a baffle-type muffler first, and then an absorption-type muffler from Burns stainless. All you can hear is the prop.
 
lufthans.nl said:
But.... on the other hand.. long, narrow nose, radiator under the fuselage, just aft of the trailing edge of the wing. The shape of that tailfin and rudder. Tapered wings. That's crying out for invasion stripes and nose art, isn't it? ;)
Hans
Click to expand...

I thought exactly the same thing! I'd love to see that.
 
Speaking as someone who deadsticked a Mustang in to Fargo on Saturday,

I like my Lycoming just fine........

The P-51 would be the perfect airplane if it had a P&W 2800 on it!

Anytime you are flying a Mustang, if you aren't thinking about the cooling system, you aren't doing your job. Granted the hot water toilets are faster and more efficient, but the aircooled engines are much more dependable....

This time it was a fuel delivery nozzle problem, not cooling, but the cooling system is high maintenance.....

Tailwinds,
Doug Rozendaal
 
You're flying a mustang?

Cool! (if you pardon my pun)

Mind you, a 300 hp Subaru would be very much easier to cool than a 1500 hp Merlin.

Okay, mine is not turbocharged, so less heat to worry about, but if I take the thermostat out of my cooling system, I'm strugging to get my coolant temps over 150F and my oil temps over 180F. Even on a hot day during a sustained full power climb.

I've really got the feeling that one particularly bad design choice by a great majority of builders who are messing around with liquid cooled aircraft engines has given these engines somewhat of a bad reputation where cooling is concerned. If you want good and efficient cooling, then a radiator should NOT be in the engine compartment. And if it really must be there, then please don't use the same cooling openings that a Lycoming is using. It simply won't work efficiently. Sure, if you make the holes large (and draggy) enough, then you might be able to get it to cool reasonably well, at the loss of 30 kts top speed. See Eggenfellner.

But I'll stow this soapbox of mine away now...

Back to Rockets: How would you compare the Rocket to a Mustang?

Hans
 
Hans,

The problem with the cooling system on the Mustang is not it's ability to cool the engine, it is how fast things fall apart if it fails. And all cooling systems are fragile. Nearly all on road failures in Class 8 trucks are cooling system related.

And Tom, it was the -C model... The fuel delivery nozzle got a piece of dirt in it, that allowed manifold pressure (vacuum) to suck the fuel out of the "C" chamber in the carb which prevented the poppet valve from opening and delivering fuel.... Run die, run die, run die... then when I had the airport made, I pulled the power back and it quit.... More adreanaline than I need again for a long time....

Tailwinds,
Doug Rozendaal
 
Doug,

Good to hear you made it down safe and sound.

I can only imagine what was running through your head while all that was going on.
 
lufthans.nl said:
Okay, mine is not turbocharged, so less heat to worry about, but if I take the thermostat out of my cooling system, I'm strugging to get my coolant temps over 150F and my oil temps over 180F. Even on a hot day during a sustained full power climb.

I've really got the feeling that one particularly bad design choice by a great majority of builders who are messing around with liquid cooled aircraft engines has given these engines somewhat of a bad reputation where cooling is concerned. If you want good and efficient cooling, then a radiator should NOT be in the engine compartment. And if it really must be there, then please don't use the same cooling openings that a Lycoming is using. It simply won't work efficiently. Sure, if you make the holes large (and draggy) enough, then you might be able to get it to cool reasonably well, at the loss of 30 kts top speed. See Eggenfellner.
Click to expand...

Just so I can pass the info on......

Where are you installing your radiators? A friend has an RV8 with a 6 cyl. Sub/Eggenfellner. The radiators are in the cowl, and all kinds of modifications have taken place in an attempt to help the cooling problems. They've now removed the thermostat ; just to make it flyable. So far, the cost and associated problems have been very disappointing. And of course, installing a P-51 type radiator wouldn't be very practical at this point. Might look good.....though!

L.Adamson ---- RV6A 180Lyc
 
Two interesting comments Doug made about his Evo when we spoke at OSH.

1. "It is the only plane I have owned where I wasn't thinking about the next airplane I would like to own."

and

2. "It flies just like a Mustang."

Doug, do you want to elaborate on those comments?
 
N941WR said:
Two interesting comments Doug made about his Evo when we spoke at OSH.

1. "It is the only plane I have owned where I wasn't thinking about the next airplane I would like to own."

and

2. "It flies just like a Mustang."

Doug, do you want to elaborate on those comments?
Click to expand...

Sure,

1. There is no other airplane currently available that performs like the Rocket and retains the low stall speed that I believe is imperative for a single engine IFR X/C airplane. Look at the choices, Glasair III, SX-300, Questair Venture, Lancair, anything (except the evolution), they have horribly high stall speeds fragile landing gear and zero tolerance for wing contamination (ice). These airplanes wont work in my operation....

2. The Rocket, especially the EVO, captures the look, and more importantly the feel of a fighter. I let Paul "Harb" Brown, the West Coast A-10 demo pilot fly mine, and he has flown some others since and he is blown away. He has been ranting and raving about how it flies just like a jet fighter. Fighter airplanes have certain personality and the Rocket has it. The RV's have some of it but the Rocket takes it to a whole new level.

Specifically to the P-51, Larry Lumpkin and I were going to Barksdale AFB airshow and I wanted to check Larry out in the Rocket, so he flew it and I flew the Gunfighter. Normal cruise in the Mustang is 33"/2300rpm. That give you about 210 KIAS and depending on altitude 235 TAS.

I normally run WOT/2300rpms and climb till I get 23 inches, 7,8, or 9000 ft. I told Larry to push it up to 2400 and we were at 9500 truing 210 kts. I was running 30"/2100 in the Mustang.... instead of 60 gph I was burning 45 GPH. Larry was leaned back listening to XM and trying to learn all the electronics in the Rocket. He said, "this has everything we have in the Airbus, and it flies like the Mustang."

I practice my airshow routine in the Rocket and when I get in the Mustang, while the maneuvers are smaller, the rhythm of the whole routine is exactly the same.

And today, if the TRWs allow, I will leave my office at 10 am fly IFR to Kansas City for lunch and a meeting and be back in the office well before 5 pm all on about 30 gallons of gas.

Truly an amazing airplane.

Tailwinds,
Doug
 
she's a keeper!

N941WR said:
Two interesting comments Doug made about his Evo when we spoke at OSH.

1. "It is the only plane I have owned where I wasn't thinking about the next airplane I would like to own."

and

2. "It flies just like a Mustang."

Doug, do you want to elaborate on those comments?
Click to expand...

I've been telling folks these exact phrases since my 1st flight in an Evo (Dec 2003). I get some pretty weird looks, like I'm selling snake oil...but it's the truth. You can read what Doug wrote on the TR website if you'd like -- this was written before he owned the plane.

http://www.teamrocketaircraft.com/report/doug/doug.html

Now, if I could get it to fly like a Corsair, I'd really have something!:D

Carry on!
Mark
 
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F1Boss said:
I've been telling folks these exact phrases since my 1st flight in an Evo (Dec 2003). I get some pretty weird looks, like I'm selling snake oil...but it's the truth. You can read what Doug wrote on the TR website if you'd like -- this was written before he owned the plane.

http://www.teamrocketaircraft.com/report/doug/doug.html

Now, if I could get it to fly like a Corsair, I'd really have something!:D

Carry on!
Mark
Click to expand...

The sport wing airplanes do fly like a Corsair, They both have 23012 airfoils and aircooled engines!!!! The Corsair has lots of power and lots of drag so it is very easy to put it where you want it with the throttle, the Rocket requires a little more anticipation.

Doug
 
DOH! Clarification...

B25Flyer said:
The sport wing airplanes do fly like a Corsair, They both have 23012 airfoils and aircooled engines!!!! The Corsair has lots of power and lots of drag so it is very easy to put it where you want it with the throttle, the Rocket requires a little more anticipation.

Doug
Click to expand...

OK: I should have said that I want the Evo to fly like the Corsair...which will involve some aileron tweaking. Not that hard to do. I do not plan to increase the drag as we are somewhat power limited (the 2800 will not fit our airframe).

How'm I doin'?;)

Carry on!
Mark
"STEER FOR THE DITCH!":eek:
Anon radio transmission heard while on final at OSH -- I believe there was a crosswind..
 
F1Boss said:
?;)

Carry on!
Mark
"STEER FOR THE DITCH!":eek:
Anon radio transmission heard while on final at OSH -- I believe there was a crosswind..
Click to expand...

It wasn't me on the radio, Honest! I did not see your landing.

I think it was me in your head, because those were the words that were pounded into me when I learned to fly the DC-3.... I have been pounding them into the heads of T/W pilots every since.... It must have worked, I did not see a Twin Beech in the Ditch....

Doug
 
Mark and I have had this discussion several times so we might share it here....

If Mark could make the Rocket indicate 200 KIAS instead of 180 with power or by reducing drag, or a combination of both, unless the stall comes up, or the aspect ratio increases dramatically, or it has some sort of lift dump device, the ride in turbulence will be totally unacceptable.

Moving the CG forward will help some, but even then if the stall speed is 50 KIAS and the cruise indicated is 200 KIAS that means there are 16 Gs available and that is before the nose goes down for descent.... ..

That is the dilemma that any airplane that seeks to exceed the performance of the F1 EVO faces. Raising the stall speed is the simplest option and based on the Lancair sales, pilots will accept this, but the accident statistics will follow an increase in stall speed....

For Cross Country travel, small turbo would increase cruise speed, and there is room under the hood of the -550 airplane, but Cirrus and Continental tried repeatedly to turbo the SR-22 and failed.... The guys in Ada OK figured it out and made it work. That was a huge project that demonstrates the difficulty of getting a dependable turbo installation. Probably not reasonable for the homebuilt crowd......

A supercharger is a power liability until you get up to altitude where it can work its magic, and single speed superchargers work in a very narrow altitude range. So that is a poor choice....

Every thing in aircraft design is a compromise and The Lycoming EVO Rocket is at, or is very close to, the pinnacle of the compromise curve in many areas.... IMHO of course....

Tailwinds,
Doug
 
The Need for Speed...

Hey Doug:

Good post. I'll try to address a few of your statements:

The new production Evo kit will have the carbon wing, with the span reduced by cutting the wing planform at the root. This will allow for the greatest reduction in area vs span. The plan is for 90SF, with a figure closer to 80SF being optimal for all-out speed (stall speed would not be considered in this equation). In the real world, we need to look at such things, so we will opt for a slightly larger wing area to keep approach speeds in a reasonable range.

This wing area reduction will allow the ship to accelerate a bit, but more importantly, it will allow higher IAS in mild turbulence, as would be seen in a descent from 17000MSL. I still think you gonna have to pull the big knob back a bit (sorry about that!), or get a thicker bottom cushion!

We will also have a tip extension available if it turns out that more wing area is better suited to your mission profile.

I hope we can make the wing so it can be retrofitted -- that has not been determined yet.

The retracts will be the key to a 200KIAS speed, while forced induction + higher cruise altitudes would be the key to higher KTAS. In either case, I'll wager the power required is gonna go up a bit.

If you have not done the math, 200KIAS at 1500MSL = 260KTAS. We're gonna have to look at the flutter margin *again* if we're gonna go that fast!

I disagree with the turbo addition -- it's less user and maintainence friendly compared to a blower (IMHO), and we can tune a blower to a certain altitude & RPM combo easy enough. We both fly supercharged ship on a regular basis -- wouldn't you think that setup would be easier to learn, with most pilots coming from the normally aspirated world?

My plan for 158 is to change pistons and add a blower at some point (either using a front drive as is done by Aero Superchargers out of Las Vegas or a rear drive used by another company out of Colorado, or maybe a Wipple-type unit developed by Tom at G3 Ignitions). We are, of course, talking about a highly specialized setup here -- not for low altitude work (below 10,000MSL) tho it will work there -- it is optimized for 15000-17999....or Reno...;)

Lucky for us: the CG of the ship is far enough forward to allow this added weight (forced induction).

More later!
Mark
 
Wow Mark, you've been busy!

So... carbon wing retractable? Sweeeeeet!!!!

Can't wait to see pics of that one...

Hans
 
L.Adamson said:
Just so I can pass the info on......

Where are you installing your radiators? A friend has an RV8 with a 6 cyl. Sub/Eggenfellner. The radiators are in the cowl, and all kinds of modifications have taken place in an attempt to help the cooling problems. They've now removed the thermostat ; just to make it flyable. So far, the cost and associated problems have been very disappointing. And of course, installing a P-51 type radiator wouldn't be very practical at this point. Might look good.....though!

L.Adamson ---- RV6A 180Lyc
Click to expand...

I've got two radiators inside my wings. My aircraft is a Jodel, which is a 1950's design French aircraft which at the time won just about every race in its class. The Jodel has very large chord wings (nearly 6 feet), because of that it is also fairly thick (9 inches) and is has one big box spar and no second spar. All of this makes it a perfect platform for a pair of Spitfire-like radiator pods under/in the wing. The pods are nearly 5 feet long and feature a nice expanding duct to slow the air down, then he radiator, and then a contracting duct again to re-accelerate the air. It works brilliantly!

Because of their placement (between the first two ribs of the wing, underneath the wing walks), the rads are in the prop wash of the outside half of the prop. And contrary to the roots of the blades - where Eggenfelner puts its intakes - there is quite some breeze there. As a result, I can run it on the ground all day with no overheating. During flight, there is plenty of undisturbed air coming in, so brilliant cooling there too.

Retrofitting this on an RV8 would be a LOT of work though. Plus the RV wing isn't quite a suitable for this as mine is. If I were to do an RV-8, I think I'd have a hard time chosing between P-51 style or Spitfire style cooling... I think in the end the Spitfire would win...

I suggest your friend takes a look at the SDSEFI.com web site to learn how Ross tackled cooling with his RV6 and how he's doing cooling on his RV-10 project.

Hans
 
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