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Honda 1.8L on RV6A Now Flying!

Was the old unit operational or broken?

Dan,

No, it was 100% functional and from everything I could tell it was in very good shape. But he recommended the HD version since I was planning on using a turbo engine and it just made sense to me to go with the stronger box.

He uses the standard box for the 1.5L NA honda. I am using a 1.8L engine and planning on some very light turbo boost (5lbs).

Plus I do like the improved venting and site glass in the HD version.

Charlie
 
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earlier pictures

Hey Charlie,
very good infos. Just started to reread from the first page. The R18 seems to be a real good start for a conversation - lightweight, powerful and the last generation without direct injection. Your posts start with a running engine. Do you happen to have some pictures from earlier stages?
 
Hey Charlie,
very good infos. Just started to reread from the first page. The R18 seems to be a real good start for a conversation - lightweight, powerful and the last generation without direct injection. Your posts start with a running engine. Do you happen to have some pictures from earlier stages?

Tom,

I did look back for the early pics and found these two, not sure what you are looking for but this is about as early as it gets....

Here it the weight of the longblock- including the starter of course.....

oWY.jpg
 
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Hey Charlie,
very good infos. Just started to reread from the first page. The R18 seems to be a real good start for a conversation - lightweight, powerful and the last generation without direct injection. Your posts start with a running engine. Do you happen to have some pictures from earlier stages?

Tom,


This one shows the internal oil separating channels that are normally covered with a plate...

oWl.jpg


Charlie
 
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Thanks for the pictures Charlie.
From your Youtube Favorite List I assume you are no professional welder or automobile engineer, but rather someone who is willing to invest time and effort in learning new skills. Where did you get all that knowledge to get to such an amazing result?

How did you start you alternative engine project?

What did you remove from the engine?
How did you select anchor points?
How was the original throttle modified?

How difficult is it to wire all sensors, ignition and stuff to the SDS EFI?

This list goes on endless.... So where best to look for answers?
Sorry for so many questions. Hope you don't mind...
 
Thanks for the pictures Charlie.
From your Youtube Favorite List I assume you are no professional welder or automobile engineer, but rather someone who is willing to invest time and effort in learning new skills. Where did you get all that knowledge to get to such an amazing result?

How did you start you alternative engine project?

What did you remove from the engine?
How did you select anchor points?
How was the original throttle modified?

How difficult is it to wire all sensors, ignition and stuff to the SDS EFI?

This list goes on endless.... So where best to look for answers?
Sorry for so many questions. Hope you don't mind...

Tom,

Some people are mechanically inclined, some are not. And building an experimental airplane is certainly not for someone who does not like to work with their hands and build things. Some are comfortable building a kit plane but would not think about tackling an "alternative" engine. I guess it just depends on how you are "wired".

I work hard at learning from real "been there done that" folks. We have a very active local EAA chapter here and there are a lot of folks who have built planes and were very helpful to me. I was one of about 6 guys who built RV planes in our EAA chapter. My kit was probably one of the last "no holes pre-drilled or punched" kits. I drilled, deburred, dimpled or counter sunk ever hole myself. Not bragging just sayin'.

I got my private in 1980 and I have been active in EAA for most of the past 40ish years. I have seen lots of successes and lots of failures. Truthfully there is nothing special about me but other than I try to keep an open mind to learn from both.

As far as the engine and the set up go, you mentioned the sensors and ECU. I cannot say enough good things about the SDS EFI and the over 2 decades of support that Ross and Barry have provided. Truly unparalled support. The system just makes the set up programming of the ignition and injection systems easy.

Back to the engine. There are a lot of great engines out there. You just need to figure out which one that has the right power, weight, and history of longevity that works for your set up. And find a PSRU / reduction drive gearbox that is appropriately sized and shaped (offset) that you need. This can be more difficult than the choice for the engine.

I hope that answers some of your questions, hope so.

Time will tell about my set up, it is too early to call this a success . I feel good about the progress but the proof will be in how well it turns out in the end, and that is still a ways off. We shall see.....

Charlie
 
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Thank you Charlie,
as hinted I worked myself thru the SDS-EFI homepage. Not for the first time, but better understanding each time. Not that the internet would not be an overwhelming source of information, but Ross speaks true facts without promising miracles. I like his tech and faq pages a lot.

When you have chosen the Honda R18 engine, what where your second best candidates?
 
Thank you Charlie,
as hinted I worked myself thru the SDS-EFI homepage. Not for the first time, but better understanding each time. Not that the internet would not be an overwhelming source of information, but Ross speaks true facts without promising miracles. I like his tech and faq pages a lot.

When you have chosen the Honda R18 engine, what where your second best candidates?

Tom,

There are aspects of many other engines that I do like. The Subes are great engines. There is a lot of success with them out there, just look at SDSEFI page and you can see lots of them flying with hundreds of hours. I also liked what Tracy Crook did with the Mazda down in Florida in the 90's too but it fizzled out when he retired. But in the end the Honda did it for me.

I actually had a Toyota 2.7L (3RZ-fe) on a test stand for a year with a PSRU I built myself. Loved the engine, and the gearbox, but it turned out to just be too heavy for my RV6a.

I think there are many good choices out there but most important each builder just needs to find the one that is right for their project. What may be right for me may not be right for someone else. Some have more time than money and others have more money than time. Some, like me, really enjoy the power plant side of the building process as much as the air frame side of the project. Others just want to buy an off the shelf product. Some need a ton of support from fellow builders others not so much. I think that people just need to think long an hard before jumping in to a project and really ask themselves if they have the will to see it through knowing that there will be challenges and set back but for those of us who are wired that way, it can be incredibly rewarding in the end.

Charlie
 
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I promised that I would get some pics out on the new "Turbo" PSRU. I have not installed it yet. I have been too busy welding on the mount. But the mount is done and I got some time on the new pics.

Here is an overall shot with it on the scales. This includes oil.

oWZ.jpg


Here is another one of that site that shows the oil level.

oWi.jpg


I am very happy with this PSRU and Jan has been very good to work with. I want to make remind folks that I am only using the Viking gearbox and not his engine. In case some may want to caution me about Jan at Vikings past, just know that I am very familiar with it. It is what it is.

For me, I really like the "Alternative" engine route. I can replace the entire engine for $1000 +/-. And all parts like starters, alternators, filters, belts, plugs, etc, can be found at virtually any parts stores in any town. I like that.

Just guessing I suspect most will want to know $$ of the PSRU....I probably have $4500 in total in the PSRU, counting the original unit, the guibo, drive spider, upgrades and all. It is a lot of $$ for sure, but, I am happy with it.

To put this another way.....some ask "why did you put an "alternative" engine in our RV6A? I sometimes laugh and say, "Actually it was more along the lines of what airframe can I find that will work with my "alternative" engine set up!. A bit in jest but not too far off......Just me......

If there are questions feel free to ask.

Charlie
 
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From some research I did a couple of years ago for my Viking 110, the "Torsional Damper" is a SGF GAB01-017 Drive Shaft Flex Disc used on a BMW 525i E39. The original one-piece disk is cut in thirds, midway between the thicker cross-sections for the six bushings. You can see the internal construction in the SGF Flex coupling in the following document.

https://www.sgf.de/tl_files/theme/pdf_download/SGF Flyer SGFlex-flexible couplings.pdf

I presume this is a custom part for BMW as it is not listed in the SGF catalog.

It appears the flex disk was used as a one piece unit at some point and then sectioned into three pieces to address a problem. I suspect the problem may have to do with the drive pins (flywheel side) and driven pins (gearbox side) not being parallel or spaced precisely to distribute the load equally. I recently changed the aluminum flywheel to a steel one and replaced both the flywheel side and gearbox side pins. Installing the flex coupling as a one piece unit found some binding on a couple of pins, that goes away with the sectioned coupling parts. There is an installation note to make sure the flex coupling sections are installed to keep the gearbox side drive in tension as the engine rotates.

John Salak
RV12 N896HS
 
Johns post is correct. But just to clarify, individuals are not cutting these up in the field. The ones that Viking sells is sectioned, as John describes. As always it is up to the individuals whether they want to use the disc whole, or as Viking supplies, sectioned.

These are used in most of 300-500 series BMW drive shafts, and many other vehicles as well.

As far as the "why does he section them"...that would be something Viking should answer.

Charlie
 
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A couple guys have reported failures at low hours of these parts on earlier Viking drives, not sure if the present part is the same as on the earlier version.

Cutting something like this doesn't sound like a good idea or being based on any science or recommendations from the manufacturer.

Redrive makers should really invest in the proper equipment to test for TV and use appropriate means to fix any concerns which show up.
 
I am not familiar with any failures, or even problems with the flex discs. Ross, please post here what you have heard. It would be of interest to me and I am sure others.

I am pretty active on the Zenith forum where a lot of folks are using the Viking engines and redrives. That forum is not controlled by Viking and hence people are free to post info, including complaints or troubles. The only troubles I have read about that I can remember seeing is relating to the issue of venting. I know Viking did experience some high oil temps on the gearbox when they mounted the redrive on the turbo charged engine. That caused them to create a new HD "Turbo" unit that has larger bearings and an improved venting system.

I personally don't "see" a need to section the guibo. The un-cut disc I use slips on and mates the engine and the redrive nicely.

I think it is good to look hard at the unit, the redirve, the flex disc, etc.

The only thing I would ask is that before we go down the path of "Looks good to me" or "You should not do that" or "I would not do that" I
respectfully ask that critical statements be coupled with the person posting the critique what their level of training, experience or education is. It really helps all of us as we contemplate the advice.

Make sense?

Thanks.

Charlie
 
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I'm following this thread with great interest. Thanks...

Welcome to the party. It is a good group, IMHO, who are willing to ask questions, offer advice and respectfully debate the merits of the project. There are many encouraging words of support as well.

Charlie
 
I recall getting an email from someone with a 110 who had 2 failures in less than 40 hours a few years back. I'll search my emails at work Friday but likely been dumped by now.

Does Jan say how he tests his drives or what led him to recommend these mods to the coupler? Unless he can tell you something based on facts and testing, this sounds like a shot in the dark.

Seriously, anyone making and selling drives to customers needs to have a proper test program in place, not relying on customers to find issues because insufficient engineering and testing went into it to begin with.

Yes, we know these are experimental parts at Experimental prices and it's up to the user to decide if it's a good idea to use them. I hope your experience with the drive is good and above all, safe.

I'd be interested in your observations of any signs of TV in the 500 to 1500 rpm range.
 
I recall getting an email from someone with a 110 who had 2 failures in less than 40 hours a few years back. I'll search my emails at work Friday but likely been dumped by now.

Does Jan say how he tests his drives or what led him to recommend these mods to the coupler? Unless he can tell you something based on facts and testing, this sounds like a shot in the dark.

Seriously, anyone making and selling drives to customers needs to have a proper test program in place, not relying on customers to find issues because insufficient engineering and testing went into it to begin with.

Yes, we know these are experimental parts at Experimental prices and it's up to the user to decide if it's a good idea to use them. I hope your experience with the drive is good and above all, safe.

I'd be interested in your observations of any signs of TV in the 500 to 1500 rpm range.

Ross, I will ask Jan about testing he has done that prompted him to cut the disc. I agree, it seems counter intuitive at best. Like Dan said, it certainly goes against what SGF designed. That said, I just have not heard of any issues.

Dan share with us if you get the Newton Meter ratings on the GAB01-017. For the sake of the topic, this particular model has a 96mm bolt circle, with 12mm lugs and it is 30 mm thick. There are other discs with the same bolt circle and lug diameter that are thicker. I presume they have more -strength. The thicker discs are used in more powerful and heavier vehicles, i.e. the Cadillac CTS, etc. One of the more comprehensive lists of discs can be found at

https://www.powertrainindustries.com/catalogs_type.htm?type=Rubber+Flex+Discs

For those who want to look deeper in to the "cut" disc topic Viking has videos on their website and on youtube where they describe this in their own words. Better you see it and hear it from Viking direct than from me.

As far as my own experiences, I only have probably 30-40 hours on the test stand. I have ran it up to 5000 rpm many times (that was really fun for my neighbors) and I did not notice harmonics from my anecdotal observations. But in fairness I was not directing my attention to this. I was more focused on nailed the programming values of the ECU.

I also want to state that what I experience with my set up may not be representative with what anyone else may experience. I moved my alternator over to the other side of the engine to balance out the weight with the turbo. That along with the prop extension and prop will create its own unique pattern of frequencies. I am open minded that it may turn out great, and it may not. So far I am very pleased with the performance. once the migration to the airframe is complete and functional. I will move on to purchasing a larger prop ( IVO MAGNUM 74" 3 Blade?) so I can work the engine harder. The 3 bladed 68" warp is a great prop, but it does not seem to be enough to really work the engine.

Charlie
 
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Charlie, you sad earlier that the Viking Gearbox was almost a straight fit. 3 holes lined up excactly and one not. Was it the upper right point (frontview) that needed a little adapter?
And to add one more stupid question... Would you imagine it possible to bolt lycoming style mounting ears to the R18 and use the original Vans engine mount?
 
Seriously, anyone making and selling drives to customers needs to have a proper test program in place, not relying on customers to find issues because insufficient engineering and testing went into it to begin with.

+1, this is especially important (essential) for torsionals. Many times there is no external indication of trouble until parts escape their enclosure.
 
My observation of the past comes from Jan rushing numerous things to market before sufficient flight testing was done and customers were left holding the bag to buy "upgrades" and even mandatory "upgrades" to fix multiple problems on engines, ECUs, turbo systems, engines, redrives etc. He also has a history of repressing any talk of failures or even hard questions about his designs.

My question to you was- has he learned and changed the way he approaches new product development, testing and customer feedback?

I can't believe SGF would condone cutting their coupler in any way. This just sounds like a very bad idea to me.

I've met and worked with Jan years ago and he is a smart guy, but no matter how smart we are, we don't know everything as we find out as we get into these projects. I hope Jan consulted SGF before this recommended mod but I strongly suspect he didn't, from past experience.
 
Ross did post it previously. Apparently it was on the Zenith forum. If you compare with the previous photo of a failed coupler, you'll note they are definitely not the same one.

http://www.vansairforce.com/community/showpost.php?p=1141225&postcount=3

Here is a Viking video of an upgrade to the driving and driven components. The cut coupler appears at 2:30.

http://www.vansairforce.com/community/showpost.php?p=1141225&postcount=3

They are both the same link Dan

I am interested in viewing the video
 
A neighbor and good friend has a experimental Cub powered by a Honda Fit engine with a belt redrive copied from an Enstrom helicopter. The crankshaft pulley uses a center disc out of a manual transmission. At around 700 RPM torsional vibrations will force the clutch springs to nearly bottom out. Virtually no vibration from there on up. His workmanship is top-notch.

The giubo's shown here look nearly identical to the one in my 911 C4.
 
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Charlie, you sad earlier that the Viking Gearbox was almost a straight fit. 3 holes lined up excactly and one not. Was it the upper right point (frontview) that needed a little adapter?
And to add one more stupid question... Would you imagine it possible to bolt lycoming style mounting ears to the R18 and use the original Vans engine mount?

Tom.

In order to use the bolt pattern of the viking gearbox, I did add a 1/2" steel plate that allowed to capture transmission bolt sockets as well as bolts from the gearbox.

I cannot see a viable way to use a Vans mount with an R18 without creating another adapter mount between them. Especially if you had a dynafocal mount. So fir me it just easier to start fresh, with the exception that I use the lower section with the nose gear support - that was Vans OEM.
 
This topic reminds me of one of the leaseback planes I used to rent. May be a C177RG??? Not sure. But I do remember it was plarcarded with a warning not to stay in a certain RPM range. There was a destructive resonance in that RPM range.

When I get the system operational on the airframe, I would very interested in getting a few planes together and do some vibration testing to see what each plane's characteristics really are. I do know a A+P mechanic who does some advanced testing, I will see if his equipment can do this type of testing. I think it does.

As far as the picture of a cut disc a few posts back I did not see any information that explained anything.

To strive for information and knowledge we should all look for successes, and failures and learned as much as we can from all sides.

And of course, lets keep it friendly.

Thanks

Charlie

Charlie
 
I think it is a very good idea for people to test their powerplant set ups to learn where the troubling harmonics are. It is great if the operational frequency can be found low enough in the RPM to be able to transition through it at a lower power settings.

It is also great if you can have the higher harmonic somewhere above the operational range, say 5500 rpm.


I also think it is a great idea to buy friends beer at OSH. But it wont be because someone called me a fool for using the term "dampner" instead of "coupler". Geesh, that is a bit over the top!

Also, I think it is circumspect to bash the land of the Vikings without having any idea what testing they have done, or not done. May be, just may be they did that testing and found that by sectioning the flexible disc, it moved a troubling harmonic up past the operational range? I personally don't "like" the idea of sectioning the guibo, but we really don't have enough informatin to be critical of the decision - other than - it sure goes against what SGF had in mind...


Charlie
 
I'm pretty familiar with what Jan has done over the years being a supplier to him for several years and following the Viking project from the start. I'm also privy to lots of feedback and information from customers who came to me for advice and ECUs who were unhappy customers of Jan. Information most other folks never hear.

To be fair, I've also talked to quite a number of his customers who have been pretty happy with his products too.

Nobody should be won over by some pretty CNC work you see on the outside. Just like people, it's what's inside that really counts.

You don't need to be an engineer to design a successful redrive as we've seen some examples designed by experienced gearheads and machinists which work well with few problems but it's probably pretty helpful.

You could have excellent service and reliability from this drive but the cutting of an engineered coupler (not actually designed for this drive in the first place) is a big red flag to me. I'd urge you to try to learn more about this aspect from Jan if possible. Asking some hard questions might enlighten you and save you some trouble down the road (or get you excommunicated).

We want you to succeed and I'd like to see something like the Viking drive be reliable and reasonably priced and readily available for others who want to experiment with auto conversions because too many other drives are priced way out of the marketplace IMO.
 
Ross
I appreciate that you are respectful of others even when you disagree and you offer constructive criticsm that is not offensive. Then you end it with genuine hope for success and safety. Well done.

I have posted on the Viking forum on the Zenith page an open letter to Jan asking why he cuts up the discs. I asked if there was engineering behind that decision and if so, if he would share it with us. I also asked if there were problems with using the disc whole. I just posted it earlier in the day. I have not heard back. I suspect he will answer it. when he does I will share it here.

I also want to dig towards any failures of the discs and try to learn what cause the failure. IF they are out there it will be easy to find them..

It reminds me when IVO has several props failing about a decade ago. People were furious and wanted him lynched. The fact is the issues were mostly cause by some end-users not properly following the installation instructions and I believe IVO instituted some improvements along the way as well. Today, there are few troubles with IVO props. Some give them high tumbs up. Others a big thumbs down. Yet they are using the same prop, with some improvements they have learned along the way.

I really would like to test my set up for resonance frequencies once I get farther down the project. Hopefully I can fine someone who is experienced and does not cost too much had has good equipment. Right?

Charlie
 
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To strive for information and knowledge we should all look for successes, and failures and learned as much as we can from all sides.

There is only one side here, and it is yours. This is all written to help you. You asked for real world experience, and this is what it looks like.

Your comment about there only being "one side and it's yours" is not accurate, and came across as disrespectful. Anyone following this thread will know I am open minded welcome comments as long as they are respectful. People will generally value and receive your posts if show them respect.

Please keep this in mind as you share information.

Thank you.

Charlie.
 
OK, no dog in this fight-------just a couple observations.

There is only one side here, and it is yours. This is all written to help you. You asked for real world experience, and this is what it looks like.

Your comment about there only being "one side and it's yours" is not accurate, and came across as disrespectful.

A matter of perspective IMHO-------I saw nothing disrespectful in Dan's statement.

People will generally value and receive your posts if show them respect.

Please keep this in mind as you share information.

Thank you.

Charlie.

I, and I suspect many other VAF members value Dan's posts no matter how they might interpret his delivery.
 
As Charlie stated, yes, even designs with considerable engineering and testing behind them sometimes have problems (Toyota, Honda etc.) and need some tweaks or re-designs. We should use all resources at our disposal and (and within our budgets) to try to do the best job we can first time around.

It's probably unrealistic to expect no problems on an auto conversion, we can only hope they are minor and easily fixable. We learn, fix and move on to the next.

In the end, Charlie will run this drive with some coupler and prove or disprove the reliability of the whole thing on this engine with X prop. That's valuable information for others and noble cause. My hat is off to anyone who goes down this path, learns and shares the outcomes, both good and bad.

Thank you Charlie for being an experimenter and starting this thread. I find it very interesting as I'm sure others do. Lots of views here.
 
Your comment about there only being "one side and it's yours" is not accurate, and came across as disrespectful.

"There is only one side here, and it is yours" simply means "There is no "other side"... I'm on your side."

The goal is to keep you alive.
 
"There is only one side here, and it is yours" simply means "There is no "other side"... I'm on your side."

The goal is to keep you alive.

Not your responsibility.

For the sake of everyone who enjoys reading about the project please keep it mechanical and - please - avoid not so much personal stuff.

Thank you.

Charlie
 
In the end XXXXX will run this drive with some coupler and prove or disprove the reliability of the whole thing on this engine with X prop. That's valuable information for others and noble cause. My hat is off to anyone who goes down this path, learns and shares the outcomes, both good and bad.

Noble cause? Ross, this is driveline engineering, a mature science. Stop encouraging the million monkeys approach* to alternative engine development.

(*Give one million typewriters to one million monkeys, and given enough time, one of them will write War and Peace entirely at random.)
 
Are these plots looking at a spinning propeller from the side?

Yes Bob. I used to generate photographs of these for stator blades in a holography lab using a real time hologram and a speaker behind the blade for the excitation. Prop companies use strain gages.

Adding: the blades will also twist as part of these mode shapes, so these are only part of the real resonance.
 
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Noble cause? Ross, this is driveline engineering, a mature science. Stop encouraging the million monkeys approach* to alternative engine development.

(*Give one million typewriters to one million monkeys, and given enough time, one of them will write War and Peace entirely at random.)

By noble, I mean I appreciate someone actually experimenting and doing something different. Your snippet of my post doesn't contain the whole context of it. (Post #240 if people are interested).

I've hardly encouraged the million Monkey's approach here Dan, just saying in the end, no matter how much engineering and testing you throw at something, it doesn't prove or guarantee anything. Toyota and Honda still have some big fails with hundreds of millions of dollars thrown at a design. Only by getting it out in the real world will you prove or disprove the integrity of any design. At some point, ground testing is over and you will have to fly it.

Lycoming and Rotax both make certified products which have known TV issues at certain RPM ranges and simply put cautions on them not to operate there. This is the same with my Sube conversion. This is hardly a "proper" fix for the problem but it generally works fine.

You've had failures with your auto conversion as did I. After the failure, we find out we didn't know as much as we should have or thought we did.

I've also advocated caution and getting more info before proceeding with lots of ground testing to follow before flight.

Yes, we should be aware of the dangers of TV and take it seriously. You have certainly educated us on that subject immensely here on VAF. I want to thank you for that education. If we scare everyone away from experimenting however, that would be a shame... A cautious, informed and patient approach gives one the best chance for success IMO. I feel you and I have done our part in cautioning and education here. I'll continue to help the OP with any questions he has to hopefully make this conversion a success.
 
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Yes, we should be aware of the dangers of TV and take it seriously. You have certainly educated us on that subject immensely here on VAF. I want to thank you for that education. If we scare everyone away from experimenting however, that would be a shame... A cautious, informed and patient approach gives one the best chance for success IMO. I feel you and I have done our part in cautioning and education here. I'll continue to help the OP with any questions he has to hopefully make this conversion a success.

Nicely stated, Ross.

Charlie, should you choose to pursue the TV further, an analytical model of the system is not that difficult and would allow data acquisition other than the strain gage technique. A gear (starter ring) tooth sensor, and proper DAQ can detect and measure torsionals. The location of the toothed wheels are the key. The flywheel and the input gear in the PRU is likely all that would be needed. You might be able to find a grad student that can do this with borrowed equipment. While not difficult, it is a very specific expertise. Modern analytical software can reduce the labor component substantially. A test stand run should be all that is needed. Your PRU supplier may have a model already, rendering all this moot.
 
You've had failures with your auto conversion as did I. After the failure, we find out we didn't know as much as we should have or thought we did.

Yes, the first one, a "tested" PSRU purchased from Dave Johnson, Reductions Inc. Remember him? It was a torsional disaster. Seemed like a good idea at the time.

A Yep, style counts.

I have removed the gauche posts.
 
My goal in starting this thread, here on VAF, was to share with others what I doing. To share my what went right what went wrong, and generally keep up with posting updates on the propgress.

I have benefited from people willing to offer advice and share their thoughts on other ways of skinning the cat. I also appreciate hearing from folks that they are following along even if it is just to find something to read while they eat popcorn.

My project is unique, and I know that. Some may find it absolutely crazy, some may find it wonderful. Its probably a little of both.

As long as there is some value being shared, and it is fun for people I will continue to post here. At over 24,000 views, I know there are several out there who have never said a word and I suspect I know why.

Hopefully this thread will migrate slightly back towards being a friendly atmosphere where folks with different thoughts and ideas can feel free to share them with without feeling ridicule. At least that is my hope.

I could have started this thread several different locations, and trust me I thought about it, but I did so because I thought there was interest on this forum. My project may be too unconventional for some and certainly out side of some folks comfort zones, but for many, it is of great interest and admiration.

.....UPDATE: I am actually out of state. But will be returning soon. I will need to pick one of the major components to migrate over to the airframe like "Cooling" or "fuel delivery" as far as cooling I plan to mostly copy Ross's set up but at this point I plant to try to do the plenum out of aluminum. He scared me away with all that talk of sanding for hundreds of hours. It will not be as pretty, but it will be as functional, I hope.

Stay tuned?

P.S. I retire my day job in April and plan to hit the project full time in the spring. I want to see daylight under the wings before the end of 2019.

But we will see how many other projects around the home come up.......uuummmm any takers on bets?

I will keep you posted. (As long as I am welcome here.)

Charlie.
 
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Yes, the first one, a "tested" PSRU purchased from Dave Johnson, Reductions Inc. Remember him? It was a torsional disaster. Seemed like a good idea at the time.

I know of Dave. Lots of folks starting their auto conversions have drunk vendor Kool-aid and been bitten by cold, hard facts in the end, including you. A few hours of testing clearly isn't enough to uncover basic design issues which may lurk on a redrive.

Everybody starts somewhere and learns a lot during this journey. I certainly did.

Charlie is starting his project with the Viking drive and has the benefit of learning from our experiences (good and bad). It sounds like he considers that valuable. Sharing info lets you learn faster and cheaper than making all the same mistakes yourself.

I look forward to the next installment here.
 
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well, i for at least one, am sitting on the edge of my chair to hear the reason the rubber puck was cut by viking.
 
well, i for at least one, am sitting on the edge of my chair to hear the reason the rubber puck was cut by viking.

I think Dan posted this link earlier:
https://www.youtube.com/watch?v=osvshgbbuAA&t=179s

Right around the 2:50 mark: It was cut "in order for the torsional forces to be dampened correctly"

So, what does that mean? This opens the door for even more questions. Was this by feel or is there data for T.V. with the disk intact? With it cut? Is this only for the gearbox or Is this specific to one engine/gerbox/prop combo?

I don't know if anyone has reached out to Viking for this info, but history has made a bunch of people pretty cynical, and we may never know.
 
My goal in starting this thread, here on VAF, was to share with others what I doing. To share my what went right what went wrong, and generally keep up with posting updates on the propgress.

I have benefited from people willing to offer advice and share their thoughts on other ways of skinning the cat. I also appreciate hearing from folks that they are following along even if it is just to find something to read while they eat popcorn.

My project is unique, and I know that. Some may find it absolutely crazy, some may find it wonderful. Its probably a little of both.

As long as there is some value being shared, and it is fun for people I will continue to post here. At over 24,000 views, I know there are several out there who have never said a word and I suspect I know why.

Charlie, I have no intentions of building/flying a one-off powerplant application as you are doing but I find your process to be most interesting and impressive. I encourage you to continue your pursuit and share the adventure with us in spite of the occasional tact-challenged comments that will arise. Looking forward to future updates! :)
 
I know of Dave. Lots of folks starting their auto conversions have drunk vendor Kool-aid and been bitten by cold, hard facts in the end, including you.

Yes, and there is no reason to see others go down the same road.

A few hours of testing clearly isn't enough to uncover basic design issues which may lurk on a redrive.

A thousand hours of "testing" won't uncover torsional issues if run at RPM outside a resonant range.

Here's an example. Assume an intersection of F1 and firing frequency resulting in peak oscillating torque at 1000 RPM, about 33 hz, an entirely likely ballpark for this system. Builder starts, pushes up to 5000, holds it there three hours. Actual period of peak driveline load was a few seconds when it passed through 1000, not the three hours at 5000.

If the builder passed through 1000 RPM at partial throttle, oscillating vibratory load was nowhere near the potential peak load. Nothing broke, so builder installs engine, goes flying, does lots of touch and goes during test. Out on the runway he moves from idle to full throttle very quickly, a throttle shove. The increased manifold pressure means peak resonant driveline load is radically higher than the part throttle case. Maybe something breaks outright. Just as likely, something begins to fatigue. That first drive? I got to 38 hours before the belt teeth came sailing back past the cockpit.

It's the million monkeys approach, blindly collecting "real world experience". Maybe one of the monkeys writes War and Peace. Maybe not.

Contrast with an analytical model, a list of measured or carefully calculated inertias and stiffness values created prior to ever reaching the test stand. Condense it to as little three elements, and run a frequency prediction with a test stiffness value for the coupler. Adjust the predicted natural frequencies by varying the coupler stiffness. If necessary, vary other stiffness and inertia values. Then design a drive incorporating the specific inertia and stiffness values which gave the best result. Or, in the case of a purchased drive, select a coupler based on its catalog values, and design the necessary connecting flanges.

Now cut metal and go to the test stand. On the stand, confirm the model predictions. Compare the loads to known component capacities.

Everybody starts somewhere and learns a lot during this journey. I certainly did.

Yes. What I learned is that the analytical approach results in a far higher probability of success. Again, this is driveline engineering, a mature science well over 100 years old. There are no fundamental discoveries to be made, no noble experiments to prove or disprove a new theory. The task is far more mundane...learn and apply known principles...education and recreation.
 
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Yes, and there is no reason to see others go down the same road.

A thousand hours of "testing" won't uncover torsional issues if run at RPM outside a resonant range.

Here's an example. Assume an intersection of F1 and firing frequency resulting in peak oscillating torque at 1000 RPM, about 33 hz, an entirely likely ballpark for this system. Builder starts, pushes up to 5000, holds it there three hours. Actual period of peak driveline load was a few seconds when it passed through 1000, not the three hours at 5000.

If the builder passed through 1000 RPM at partial throttle, oscillating vibratory load was nowhere near the potential peak load. Nothing broke, so builder installs engine, goes flying, does lots of touch and goes during test. Out on the runway he moves from idle to full throttle very quickly, a throttle shove. The increased manifold pressure means peak resonant driveline load is radically higher than the part throttle case. Maybe something breaks outright. Just as likely, something begins to fatigue. That first drive? I got to 38 hours before the belt teeth came sailing back past the cockpit.

It's the million monkeys approach, blindly collecting "real world experience". Maybe one of the monkeys writes War and Peace. Maybe not.

Contrast with an analytical model, a list of measured or carefully calculated inertias and stiffness values created prior to ever reaching the test stand. Condense it to as little three elements, and run a frequency prediction with a test stiffness value for the coupler. Adjust the predicted natural frequencies by varying the coupler stiffness. If necessary, vary other stiffness and inertia values. Then design a drive incorporating the specific inertia and stiffness values which gave the best result. Or, in the case of a purchased drive, select a coupler based on its catalog values, and design the necessary connecting flanges.

Now cut metal and go to the test stand. On the stand, confirm the model predictions. Compare the loads to known component capacities.



Yes. What I learned is that the analytical approach, results in a far higher probability of success. Again, this is driveline engineering, a mature science well over 100 years old. There are no fundamental discoveries to be made, no noble experiments to prove or disprove a new theory. The task is far more mundane...learn and apply known principles...education and recreation.

Agreed.

Flying it 1000 hours is more proof of overall drive reliability than any other test. Of course we'd like to precede that testing with an instrumented TV study or at minimum, a math study but the latter 2 actually don't prove the whole drive will be reliable in a flying aircraft. TV is only one aspect of the box integrity. Lots of other stuff could break.

The auto OEMs purposely don't just hold a drivetrain at max rpm/ max power, they cycle it through the whole range of load and rpm hundreds of thousands of times to uncover any weakness, whether TV induced or otherwise. The ground and flying testing on an aircraft redrive should also strive to follow that example.

On my plane with 400+ hours now on the Marcotte drive (never opened in that time but external couplers replaced once), I haven't see any change in backlash in the gearset and no sign of metal in the oil. I am very careful not to operate in the resonant ranges near idle just as when I operate a Rotax 912. You'll certainly lower the life of the gearbox and other parts in both cases, operating in those ranges.

I was able to reduce the amplitude of TV markedly and lower the upper rpm range in mine by adding flywheel mass. Low flywheel mass almost always results in noticeable TV in the lower ranges on 4 cylinder engines from my observations of multiple drives running on aircraft. If you've ever run a Rotax 912 on a test stand as I have, the TV is mind boggling below 1000 rpm which is why you're cautioned to set idle speed well above this. The 912 has no flywheel.

So I'm interested to see how Charlie's setup runs down there with almost no flywheel mass.
 
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On my plane with 400+ hours now on the Marcotte drive (never opened in that time but external couplers replaced once), I haven't see any change in backlash in the gearset and no sign of metal in the oil. I am very careful not to operate in the resonant ranges near idle just as when I operate a Rotax 912. You'll certainly lower the life of the gearbox and other parts in both cases, operating in those ranges.

If I recall correctly, the system requires passing through it at every taxi. It's now done with the least possible manifold pressure, rather than shoving the throttle to pass through it quickly?

I was able to reduce the amplitude of TV markedly and lower the upper rpm range in mine by adding flywheel mass.

I posted four Holzer examples earlier, since deleted. As you know, your system can be modeled when you find reason to dismantle the Marcotte for accurate measurements. No point in GIGO.

As before, the urethane bushings are a poor choice for two reasons. The model would show you one of them. And there is still the mystery of the rod bearing failures.

Low flywheel mass almost always results in noticeable TV in the lower ranges on 4 cylinder engines from my observations of multiple drives running on aircraft. If you've ever run a Rotax 912 on a test stand as I have, the TV is mind boggling below 1000 rpm which is why you're cautioned to set idle speed well above this. The 912 has no flywheel.

Yes, idle speed above the resonant range, a desirable design goal. No flywheel makes it more impressive. It didn't happen using the million monkeys approach.
 
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