Comment

Comment by John Struhar on February 27, 2012 at 8:49pm

Thanks, Craig. I hope I get a chance to take a good look at it when it's finished.

Comment by Craig Smith on February 26, 2012 at 12:50pm

If you review the stuff Paul has written about motor mount design, you may start to see why this design is better. A lot of the mounts weither try to utilize the automotive mount locations, or try to emulate a dynafocal mount. Neither of which makes for an ideal aircraft application of the rotary. Dyna-focal emulation isn't suitable because of the layered axial construction of the rotary. The automotive mount location has some of the same drawbacks, leaving at least one rotor and the front plate out in front of the thrust line transmission. the ideal point to transmit the forces of thrust to the mount and thus to the airfram in the rotary is at the in front of the engine, and behind the PSRU. The bar just adds one more load line to the fuselage, spreading out the effects of a hard landing, and some stability.

Comment by Craig Smith on February 26, 2012 at 12:31pm

You can use the same thrust plate/mount (made by Jeff Dodridge) and PSRU (RWS) with the Renesis,.Fuel consumption is dictated by HP. The P-Port 13b can develope about 250. I Don't know why one would want to go to a larger displacement, engine and then build for less HP. The older 13b should be easier to get, and less expensive as well.

I delete the political stuff, unless there is some bit of science or engineering enlightenment buried in there. Paul Lamar is a very bright fellow, and has his views quite set in stone. He is a fountain of knowledge, and what he does for the rotary community for free is really quite remarkable.

Comment by John Struhar on February 25, 2012 at 7:43pm

rotaryeng.net has a couple of RVs with mounts fairly visible. Near the bottom of the page is a PSRU mount plate with integral motor mounts. On closer examination there is an RV4 that may have an upper rod, although it appears to be mounted farther aft on the engine.

Comment by Craig Smith on February 25, 2012 at 7:08pm

The firewall can be strengthened by adding a piece of hat section .090 4130, all the way up the center length of the FW, like on the 801. A couple more layups of glass or carbon fiber on the bottom of the front cowl and that should serve to distribute the loads safely. The 640 has the same thing, just cut off about halfway up. I think just buying a few of the 801 parts here would save having to make them. I think I touched on the advantages already. Can you link to any drwaings or imagges of rotary installations so I can better contrast the design points?

Comment by John Struhar on February 25, 2012 at 3:34pm

Found the rotaryeng newsletter some time ago. You can find some useful information there if you can get past the political sniping. Your drawing appeared to show a RWS PSRU. I'm planning to use a RWS 2.85:1 with a Renesis, hoping it will be a little more fuel efficient than a p-port. Will the Renesis use the same mount?

Comment by Craig Smith on February 25, 2012 at 3:26pm

Well, you need to add some kind of attachment to the engine other than the thrust plate. You can also add a bracket to the back of the oil pan and tie it into the nose gear attach. This is pretty much over the CG of the engine. The oil pan attach will block out some space down there, I prefer to leave it clear for whatever cooling ducts, engine accessories  whatever. Also eliminates any stress cracking of the oil pan, you loose oil pressure and bad things happen, although the rotary is much more tolerant than a reciprosaur. Rotary engine newsletter is found here: http://www.rotaryeng.net  along with lots of great info on the website.

Comment by John Struhar on February 25, 2012 at 1:21pm

Craig,

I have not seen this upper vibration rod on any other rotary installation I have come across. What are the advantages, and what modifications would be required in building the firewall?