Re-examining Rotary Conversion

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ke1dzyne

Member
Joined
Oct 24, 2019
Messages
8
Location
Three Rivers, CA
Hello all. New member here. After some years off from building my One Design airframe (now ~80-90% complete) which I had intended to use a normal IO-360, I'm now ready to resume, which now means I need to re-evaluate the engine choice. I'm no stranger to auto engine conversions, having originally planned to build a SB Chevy powered Harmon Rocket prior to opting for the One Design. I've built engines and hotrodded all my life, so the auto conversions are of interest. Now I'm looking at using a Renesis in my One Design. I want to preserve the aerobatic capability of the airframe (+/-10g and inverted).

I have followed Tracy Crook and a few others back when they were more active, but have lost track of them and the overall landscape of part and systems available to use in the conversion, but I have a few ideas that I hope to start with, and hopefully get feedback from you guys that are knowledgeable in the current status of flying rotaries and available parts and systems.

I intend to start with a mostly stock 6 port Renesis. I intend to buy a JDM engine to get all peripheral systems and components for possible use or comparison. It will be freshened up with some exhaust porting.

It would use EFI and electronic ignition. I'm currently looking at redundant Megasquirts or a SDS unit, depending on price and capability. It appears the RWS EM controllers are not really a viable option now, with TC's retirement.

I would also need to mount the engine plugs up to allow building an oil sump system suitable to work with the normal lycoming inverted oil system. Another option could be going dry sump, although that is expensive and adds drive issues that I don't really like (belt drive etc.).

I've been looking at Neal Unger's redrive as a worthy successor to the RWS unit, although the 10g and aerobatic gyro loading would need examination.

I would appreciate any feedback on this application. From browsing this forum prior to joining, I see there are many active and knowledgeable members here to bounce ideas off of. Many thanks.
Keith
 

TFF

Well-Known Member
Joined
Apr 28, 2010
Messages
12,258
Location
Memphis, TN
I’m Going to be conservative and say it’s not going to be a good match to a serous aerobatic airplane. Fly it, sure. Interesting sure. Not a serious contender. Another consideration is the day you go to sell it, it will be voodoo to the persons looking to buy that type of plane.
 

FinnFlyer

Member
Joined
Nov 19, 2019
Messages
9
Location
Bell, FL
+/- 10G, wow!

I spent a month or two learning Fusion360 enough to do a simple stress analysis just for +6/-3Gs to make me comfortable with my engine mount design.

Even with a lightweight wood/composite prop, I would have to check with Tracy on the RWS PSRU. I'm fairly sure the answer is no for a metal prop and +/-10Gs.

It certainly can be done. The weak point will be the PSRU and engine mount. I must admit I haven't followed Niel Unger's PSRU development.

Finn
 

ke1dzyne

Member
Joined
Oct 24, 2019
Messages
8
Location
Three Rivers, CA
I'm not planning competition aerobatics, it would mainly be a 'tear up the sky's plane, sort of an aerial dirt bike. Resale is not a concern, in fact, I would likely dismantle the plane to avoid liability concerns if I had to dispose I
of it. I just like the idea of me being the limiting factor, not the plane.

My plan is to use a wood prop. I too have fusion 360, and will be using it for designing the engine mount as well as other items. Great tool available for free from Autodesk. Gotta love it.
 

BJC

Well-Known Member
HBA Supporter
Joined
Oct 7, 2013
Messages
10,495
Location
97FL, Florida, USA
The engine mount is one part that I want to have a factor of safety well beyond 1.5.


BJC
 

cheapracer

Well-Known Member
Log Member
Joined
Sep 8, 2013
Messages
5,948
Location
Australian
Just be very careful, a good friend of mine went way too lean on his Rotary and it ended up dropping a valve ..

rotary drops valve.jpg

Put a rod out straight through the side housing as well.
 
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