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Piper J3 05-16-2020 07:49 PM

You could also wrap the pipe.

Check Aircraft Specialty or Summit Racing.


charosenz 05-16-2020 08:45 PM

Jim,

Yes. I know they also make heat shields for the turbine housing too. It would be good to put some temp sensors in there to get some data to see what is really happening. But right now I just need to try to stay focused on getting it flying!

Charlie

RV8AHopeful 05-27-2020 07:04 AM

Charlie, interesting project!

I've been curious what all goes into adapting an automobile engine to work in an airplane. On the surface, seemed as easy as plopping it in and putting a reduction drive between the engine driveshaft and the propeller, but obviously things are never that easy haha.

I'm curious: what do you think of Mercedes' M139 2 liter engine outputting 416hp? https://en.wikipedia.org/wiki/Mercedes-Benz_M139_engine

Seems like it would be the perfect automotive engine to stick in a plane? It's a Mercedes engine so you know it's going to be very reliable. And it's a 4 cylinder only 2.0 liters that is producing over 400hp. My guess is that weight will be the biggest problem? I believe it weighs 385 lbs. But given all of that power, the weight should be easily overcome so I suppose the real enemy will be CG?

Also, I'm no airplane engineer but how does one increase MTOW? Will extra power increase MTOW or is MTOW dictated by something else in the structure of the plane? Or will engine power increase MTOW slightly, up until you reach structural limits of the airframe?

So if engine power will increase MTOW then you don't have to worry about the extra weight of the engine, except for the CG, is that right? And then could you just add counter weights to rebalance the CG?

Taltruda 05-27-2020 12:30 PM

Quote:

Originally Posted by RV8AHopeful (Post 1433736)
Charlie, interesting project!

I've been curious what all goes into adapting an automobile engine to work in an airplane. On the surface, seemed as easy as plopping it in and putting a reduction drive between the engine driveshaft and the propeller, but obviously things are never that easy haha.

I'm curious: what do you think of Mercedes' M139 2 liter engine outputting 416hp? https://en.wikipedia.org/wiki/Mercedes-Benz_M139_engine

Seems like it would be the perfect automotive engine to stick in a plane? It's a Mercedes engine so you know it's going to be very reliable. And it's a 4 cylinder only 2.0 liters that is producing over 400hp. My guess is that weight will be the biggest problem? I believe it weighs 385 lbs. But given all of that power, the weight should be easily overcome so I suppose the real enemy will be CG?

Also, I'm no airplane engineer but how does one increase MTOW? Will extra power increase MTOW or is MTOW dictated by something else in the structure of the plane? Or will engine power increase MTOW slightly, up until you reach structural limits of the airframe?

So if engine power will increase MTOW then you don't have to worry about the extra weight of the engine, except for the CG, is that right? And then could you just add counter weights to rebalance the CG?

There is so much more to adapting an auto engine to aircraft than just plopping it on with a gear reduction. There are heat issues, lubrication, redundancy problems. they can be addressed, but when it comes down to it, the engine wasn’t designed for that application. I can imagine the engineer that designed whatever auto engine you are using , he would stomp his feet and pull his hair out saying, “if I knew that you wanted to do THAT with the engine, I would have DESIGNED it differently!”I have yet to see a successful auto engine conversion.. yes, people have flown auto engines on planes, but there is always problems that seem to take lots of time money and lack of promised performance.. eventually the plane either gets totaled, scraped, sold, or converted to an aircraft engine. Please someone prove me wrong and show me a successful plane with an auto conversion. If they were so wonderful, there would be a lot of them out there. There is so much more to an engine than water cooling, and prob reduction drives. Car engines don’t have the surface area on the rod bearings, or the beefiness in the crank and rods that aircraft engines do. Aircraft engines and their crank, rods and bearings are tremendously oversized for their hp load..low surface speeds on the bearings, wide crank journals, all add to their reliability. This isn’t meant to poopoo on the original poster and his project.. I support others experimenting with.. well, experimental aviation. I think it’s great that he’s doing something out of the box and having fun and learning from it. I was just addressing the guy who thought it may seem simple..

As for your MTOW question, there is a lot that goes into the max gross weight. One simple thing that I can think of is the main spar is only designed to hold so much weight, plus allowable “G” loading. Other factors to consider are fatigue cycles, motor mount, fuselage stringers etc...So no, you can’t safely increase takeoff weight based on more engine HP.

charosenz 05-27-2020 11:57 PM

Quote:

Originally Posted by RV8AHopeful (Post 1433736)
Charlie, interesting project!

I've been curious what all goes into adapting an automobile engine to work in an airplane. On the surface, seemed as easy as plopping it in and putting a reduction drive between the engine driveshaft and the propeller, but obviously things are never that easy haha.

I'm curious: what do you think of Mercedes' M139 2 liter engine outputting 416hp? https://en.wikipedia.org/wiki/Mercedes-Benz_M139_engine

Seems like it would be the perfect automotive engine to stick in a plane? It's a Mercedes engine so you know it's going to be very reliable. And it's a 4 cylinder only 2.0 liters that is producing over 400hp. My guess is that weight will be the biggest problem? I believe it weighs 385 lbs. But given all of that power, the weight should be easily overcome so I suppose the real enemy will be CG?

Also, I'm no airplane engineer but how does one increase MTOW? Will extra power increase MTOW or is MTOW dictated by something else in the structure of the plane? Or will engine power increase MTOW slightly, up until you reach structural limits of the airframe?

So if engine power will increase MTOW then you don't have to worry about the extra weight of the engine, except for the CG, is that right? And then could you just add counter weights to rebalance the CG?

I do get this question fairly often. While I want to answer some of your questions I have had to work real hard since I started this thread from becoming a forum whereby people tell other why it won't work or can't work, or shouldn't be done. (Especially when many of them have no personal experience on the topic that would suggest their opinions should be taken seriously)

As anyone who has read this thread knows - I am not an engineer. I am just a private pilot who has embraced the idea of using an alternative engine in and experimental airframe, I have followed the auto conversion aspect closely since 1980 when I got my Private ticket.

The main challenges when adapting an alternative engine in to an experimental airframe are: This is loosely listed in order of degree of challenge.

1) PSRU - Gear box. There are few manufacturers out there and fewer who have a lot of time on their units. If you cannot fine one that will serve your application well then you have a very steep mountain to climb. I use the Viking Aircraft Engines PSRU (but not their engine). It may or may not work with other engines.

2) Weight. Many auto conversions end up being too heavy. This is something that you need look in to very carefully.

3) Ignition and injection/Carburetor. Needless to say this is very significant and it is getting very unlikely you can use an automotive OEM system for an airplane application. There are many aftermarket injection/ignition systems that work well, but they are not compatible with all engines. I use WWW.SDSEFI.com and it is excellent.

4) Cooling. Adding a radiator and cooling system can be quite the challenge.

5) Time. It will take more time to adapt an auto engine on to an experimental airframe than say a lycoming.

6) Personality. To do this you have to have a intense desire to see it through. You have to have an above average knowledge of piston engines. I personally had as much drive to see the auto conversion becomeing functional as I did to see the airframe completed. For me the engine conversion has been the most enjoyable part of this project.

7) An incredibly supportive family. I cannot imagine doing this while trying to raise kids. No way. I have a very supportive wife, and no kids.

It can be done, but it is not for the faint of heart.

If others want to comment about this, please share if you personally have any experience with auto conversions. I would appreciate this and to me it is more meaningful than folks who are just expressing 2nd or 3rd hand information.

Good flying to all.

Taltruda 05-28-2020 12:18 AM

Charlie, I hope my post wasn’t taken to be a negative jab at what you are doing. I commend you and others like you who are trying something different, and I hope you enjoy the journey down the road that you are taking. I was only commenting to maybe help educate the other guy that doing an auto conversion isn’t as easy as “dropping it in”. While I haven’t tried to adapt an auto engine into an aircraft, I worked as a machinist and engine builder for over 10 years, and I have yet to see a car engine that I would use in an aircraft. Aero engines are way beefier for their hp levels than a car engine is. I would love for there to be a viable alternative engine to deliver the power, weight, reliability and beat the cost of a Lycoming, but I have yet to see one that comes close.

rv6ejguy 05-28-2020 06:31 AM

Quote:

Originally Posted by Taltruda (Post 1433875)
Please someone prove me wrong and show me a successful plane with an auto conversion. If they were so wonderful, there would be a lot of them out there. There is so much more to an engine than water cooling, and prob reduction drives. Car engines don’t have the surface area on the rod bearings, or the beefiness in the crank and rods that aircraft engines do. Aircraft engines and their crank, rods and bearings are tremendously oversized for their hp load..low surface speeds on the bearings, wide crank journals, all add to their reliability. This isn’t meant to poopoo on the original poster and his project.. I support others experimenting with.. well, experimental aviation. I think it’s great that he’s doing something out of the box and having fun and learning from it. I was just addressing the guy who thought it may seem simple..

You are wrong on so many levels here about engine design and this topic has been discussed at length here on VAF. Perhaps you can look here: http://www.vansairforce.com/communit...d.php?t=154193, page 4, post #34 to see an airplane which has been flying over 20 years now, trouncing Lyconentals in multiple SARL races using Subaru power for many years. There are many other examples.

If you aren't involved in auto conversions, you are probably not aware of the hundreds of successful auto powered aircraft flying around the world. I've been involved with dozens of them supplying EFI and consulting on systems. I've flown one myself for 17 years.

Charlie stated that he didn't want this to turn into a debate at the outset of this thread. Let's sit back and see how this all works out.

charosenz 05-28-2020 09:19 PM

Tom.

Truthfully (to a degree) I violated my own request by venturing off of the focus of this thread, which is to highlight my experiences with this particular engine and airframe. My apologies.

Ross is right that if anyone wants to debate or speculate on auto conversions there are many other threads that this can and have been discussed in detail.

So please take those thoughts and share them freely on another thread.


UPDATE:


As far as my project goes, if all goes well I plan to move the project to the airport a week from today. I really do wish I had it farther along before the move but on top of this project we are also putting our house on the market to sell and we have to clean up the shop. (Probably more than folks want to know).

I also have received about 12 hours of dual in an RV6A in the past 2 weeks which is great, but not when it comes to getting my plane flying.

I suspect there will be a 2 to 4 week window of time where my time is obligated on other tasks besides plane building.

So no fear that the project as stalled due to project related issues. Life just happens. I will share all good or not-so-good news as things progress.

Charlie

Piper J3 05-30-2020 06:46 AM

I’m reading the latest comments and following this thread with great interest. Wishing Charlie the very best...

I take exception to a comment “Aircraft engines and their crank, rods and bearings are tremendously oversized for their hp load..low surface speeds on the bearings, wide crank journals, all add to their reliability“.

In my opinion aircraft engines are designed very light and must be spoon-feed very carefully to maintain reliability. Highly-leaded fuel must be used to prevent detonation. Likewise, very conservative ignition timing is used to limit pre-ignition / knock. Aircraft engines develop case and cylinder head cracks with regularity. Air-cooled cylinders don’t stay round and shock-cooling is the enemy. Acceptable oil consumption is something like 1 qrt/4 hours. Fill engine to full mark and it blows oil overboard.

Just adding my two cents…

charosenz 05-30-2020 01:49 PM

Quote:

Originally Posted by Piper J3 (Post 1434680)
I’m reading the latest comments and following this thread with great interest. Wishing Charlie the very best...

I take exception to a comment “Aircraft engines and their crank, rods and bearings are tremendously oversized for their hp load..low surface speeds on the bearings, wide crank journals, all add to their reliability“.

In my opinion aircraft engines are designed very light and must be spoon-feed very carefully to maintain reliability. Highly-leaded fuel must be used to prevent detonation. Likewise, very conservative ignition timing is used to limit pre-ignition / knock. Aircraft engines develop case and cylinder head cracks with regularity. Air-cooled cylinders don’t stay round and shock-cooling is the enemy. Acceptable oil consumption is something like 1 qrt/4 hours. Fill engine to full mark and it blows oil overboard.

Just adding my two cents…

Jim,

I appreciate your and others support for my project but I do want to be clear that I hope to avoid mission creep/hijack of this thread to turn in to the never ending debate on alternative/auto vs common aircraft engines.

I am opened minded about my project and have been and will be very clear about the successes and setbacks of my project. I believe I have a viable plan. But since it is not flying yet, and I have not done a total W+B it is too early to call it a success or not yet. But all indications so far is that things look real good to me and I certainly look forward to the future.


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