What truly makes an engine suitable for aircraft use?

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Billrsv4

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HBA Group, I have seen some folks on the HBA site post questionable comments about Mazda based rotary (Wankel) engines. I am posting a "food for thought" write up I did when I did a program for the Livermore EAA chapter 663 a few months ago. I also showed them the prototype reduction drive which was tested and proven with many fault-free hours. I follow what I showed them with a few additional comments. You can see the direction we have been headed. I have included the link if those reading this missed it other posts.
6/30/16
What makes an engine an AIRCRAFT engine?
We as pilots would like that to mean an engine that never fails or breaks down.
Is that true of all or any current aircraft engines? No it isn’t.
Anyone on here get hit by the Lycoming crankshaft AD?
Does it mean that the engine must be direct drive? No some of the most famous aircraft engines in history have been gear reduced. Merlin anyone? Most of the later big radials were planetary reductions. Some of these were among the most reliable piston engines produced. Most aircraft engines need a high HP/weight ratio. Supercharging adds sagnifigant complication. Most homebuilts prefer NA.
So we are looking for a reliable engine with a good HP/weight that will keep running under all but the most adverse conditions. So what do we need to have for a GA aircraft? Usually between 150 and 250 HP. With an output that will allow us to swing about a 72” prop at less than 2800 RPM. When talking about homebuilt aircraft that takes us from a small Zenith to an RV-10. (Please I know the prop size is a generalization.)These are estimates but reasonably accurate. To use a currently available example, a Lycoming IO 360-A has a rating of about 200 HP depending on configuration. Using Lycoming figures, a dry weight of 335 lbs. add 13.6 lbs. of oil and you end up with 349 lbs (this might not include an alternator). So 349/200 = 1.74 lbs./HP this is likely a "best case" for this engine, trying to be generous here.
What I am showing you in the video is the honest effort to make an engine with excellent reliability, compact dimensions, and top-level HP/weight. This was all done with their own money and if I may say so considerable personal expertise. The Guys were Everett Hatch and Steve Beckham and they accomplished what many groups including NASA and Curtis-Wright did not. The put together a rotary engine, (Mazda/Wankel based), with exceptional HP/weight, (over 1 HP per pound) and very compact dimensions. They were successful! That the engine would be expensive to sell was a problem. They didn’t want to start their business with a product that would be hard to sell due to cost near that of currently certified engines. Most people would have given up, they didn’t. They went back to the drawing board and put together a different package using all they had learned to make a less expensive more production based engine and gear reduction drive. (Both!) Having worked in industry on mechanical equipment for 30 years, I was personally blown away by their efforts. I have been lucky enough to be able to befriend and work with the surviving partner of this amazing effort for about 6 years. He has decided that we may redo some of these efforts and apply modern CAD and production techniques. I am not trying to sell anything. Steve and I have discussed this and we will only release this stuff when there are finished flying examples of this technology that have been tested and we believe are ready for public use. We have decided to show a little of what is going on because it is simply tough to contain our excitement. I will show you some videos and some of the prototype hardware. I hope you will enjoy it as much as I do!
Bill​
Okay, that was the write up I showed before the videos that many on this list have already seen. I repeat the link for those that haven't. https://www.youtube.com/watch?v=EfreUJt-Fsk. I wanted to add a couple of additional comments. First, if you want a package that is trouble free it won't be easy. If you got involved in auto engine conversions to save a bunch of money, well, you might but not as much as you might think. I am not a pessimist quite the opposite, but if you value your time at all you can invest a great deal of it if you decide to roll your own auto engine conversion. I find the work very interesting but there is a great deal of work to be done. Finally, remember that the desire is to produce something that WORKS, and have a fun and educational experience while doing it. You will never get rich selling this stuff.

Bill
 

wsimpso1

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I can think of a few things that a new engine should be capable of based upon existing engines in normal operations:

Weather - Reliable when operated in rain and snow, starts in ambient temperatures from -20 to 120 F, operation from -50 to 120F (auxilary heat may be used for winter starts, restrictor plates may be used for winter operation;

Constant Speed Props - Capable of running currently available hydraulic constant speed propellers (appropriate to the engine output and rpm) with built-in mounts, etc.;

Spin Entry and Gentleman's Aerobatics - Capable of handling gyroscopic moments at max rpm and 0.75 radian/sec precession rate while using currently available constant speed propellers (appropriate to the engine output and rpm);

Current Airplane Fit - Complete engine and exhaust system (with heat shields) that packages within firewall footprint of equivalent engines (prop flange can be further from firewall if bending moment at firewall is equivalent)(water/gylcol and oil heat exchangers can be located away from cowling if they will not fit within the cowling constraint).

Now for the wish list. Do the above and this, and everything is covered:

Aerobatic Props - Capable of running currently available electric constant speed propellers (appropriate to the engine output and rpm) with built-in mounts, etc;

Unlimited Aerobatics - Capable of handling gyroscopic moments at max rpm and 1.5 radian/sec precession rate while using currently available aerobatic constant speed propellers (appropriate to the engine output and rpm);

Inverted Ops - Capable of inverted operation using currently available inverted fuel and oil system with built-in mounts;

Turbonormalizing - Capable of turbonormalized operation to 16,000 feet using built-in mounts, including packaging intercooler within firewall footprint of equivalent engines (prop flange can be further from firewall if bending moment at firewall is equivalent)(water/glycol and oil heat exchangers can be located away from cowling if they will not fit within the cowling constraint).

Billski
 

wsimpso1

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I can think of a few things that a new engine should be capable of based upon existing engines in normal operations:

Weather - Reliable when operated in rain and snow, starts in ambient temperatures from -20 to 120 F, operation from -50 to 120F (auxilary heat may be used for winter starts, restrictor plates may be used for winter operation;

Constant Speed Props - Capable of running currently available hydraulic constant speed propellers (appropriate to the engine output and rpm) with built-in mounts, etc.;

Spin Entry and Gentleman's Aerobatics - Capable of handling gyroscopic moments at max rpm and 0.75 radian/sec precession rate while using currently available constant speed propellers (appropriate to the engine output and rpm);

Current Airplane Fit - Complete engine and exhaust system (with heat shields) that packages within firewall footprint of equivalent engines (prop flange can be further from firewall if bending moment at firewall is equivalent)(water/gylcol and oil heat exchangers can be located away from cowling if they will not fit within the cowling constraint).

Now for the wish list. Do the above and this, and everything is covered:

Aerobatic Props - Capable of running currently available electric constant speed propellers (appropriate to the engine output and rpm) with built-in mounts, etc;

Unlimited Aerobatics - Capable of handling gyroscopic moments at max rpm and 1.5 radian/sec precession rate while using currently available aerobatic constant speed propellers (appropriate to the engine output and rpm);

Inverted Ops - Capable of inverted operation using currently available inverted fuel and oil system with built-in mounts;

Turbonormalizing - Capable of turbonormalized operation to 16,000 feet using built-in mounts, including packaging intercooler within firewall footprint of equivalent engines (prop flange can be further from firewall if bending moment at firewall is equivalent)(water/glycol and oil heat exchangers can be located away from cowling if they will not fit within the cowling constraint).

Billski
Oops, meant 0.75*Pi radians (135 degrees per second) and 1.5*Pi radians (270 degrees per second) for precession moments. 360 degrees per second would cover Lomczvoks and other gyroscopic maneuvers.

Billski
 

Billrsv4

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Location
NW Oregon
Oops, meant 0.75*Pi radians (135 degrees per second) and 1.5*Pi radians (270 degrees per second) for precession moments. 360 degrees per second would cover Lomczvoks and other gyroscopic maneuvers.

Billski
Dammit Billski and I thought those bearings were already big!
T.O. Bill
 

wsimpso1

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Dammit Billski and I thought those bearings were already big!��
T.O. Bill
I was not meaning to imply that anything was not already sturdy enough...

I do want to know that the thing spinning the prop will not self destruct if I do wingovers and chandelles and loops and rolls. Sometimes, a loop gets messed up and you fall out into a spin with the power on. It won't trash a Lycoming, and it should not trash a new engine either.

Billski
 

Billrsv4

Well-Known Member
Joined
Sep 29, 2016
Messages
132
Location
NW Oregon
I was not meaning to imply that anything was not already sturdy enough...

I do want to know that the thing spinning the prop will not self destruct if I do wingovers and chandelles and loops and rolls. Sometimes, a loop gets messed up and you fall out into a spin with the power on. It won't trash a Lycoming, and it should not trash a new engine either.

Billski
Billski, I was kidding my winking emogi didn't come through.
T.O. Bill
 
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