The engine attachment that came with the windrose was not as advised but luckily the previous builder had made the original maupin designed parts, so I bolted them together after redoing one of the flanges, and mounted it in the prescribed position with the engine inverted. There is really no other way to get a solid mount other than what Maupin recommended.
October 28, 1997 I have since decided to leave the motor alone until the machine is proven soarable without it. I have also questioned the small propellor and the marginal climb rate. I feel a redesign is needed for a larger slower prop. This will probably necessitate a tricycle landing gear to accomodate the larger propellor. At any rate it is left until the rest of the glider is finished.
This glider will have some difficulties on takeoff since the engine is only 37 hp. The recommended Horse power is about 50 hp for the 15 meter wing. On paper the 37 horse engine and a 32" prop will work but with direct drive at 6000 rpm I will be at about .8 mach at the tips, just before efficiency drops drastically and noise gets intollerable. Through careful fine tuning of the prop I hope to turn 6000 in climb and get my needed 37 hp. I do lack a certain experience with props and I have a lot to learn.
Another solution could be to use the small engine and prop that will act as a sustainer until such time as I can reach an acceptable rate of climb.
I consider electric start as necessary. I am hoping to approach my friends in the small motor repair business to see if there are any second hand starters about. Getting an attachment for the flywheel may pose a problem..... ]
The plane came with two engines, one a cuyuna and the other an earlier version of it by Rockwell.
Engine cowling will present a problem. The many wires and pipes in a limited width will be fun. I am planning on routing the carb to a position on top of the engine and the exhaust to the bottom with a modified muffler. I may haveto do some researc oin getting the most efficiency from my muffler.
Notes on props from That1Jim:
Kevin has been flying his without the engine and has about 40+ hrs on his. I talked to him about a week ago on the phone. He is going to use the kawasaki and direct drive. I used the hirth 2703 with 1.8 to 1 redrive and a 35" prop. I'm laying up the left wing in the morning in fact. 8-2-97. there is some pro's and con's about direct drive. you might look at the info on my web site goto my next page-windrose info. as far as the flaparon and walking arm, I also changed this area. I used hard push rod on the left side. the way the they did it with a cable and spring is inviting flutter if you ask me. I have attached a hand drawing of the walking arm that is not on the web site. with this and the photo's on the web site it should make sense I hope. On my engine I don't really have a print of the motor mount. just the note to my self and in my head. The note is the angle's and size's. I lowered my rock guard to run the 35" prop. I do have a blue print of the prop Irv Culver designed. just for the engine and redrive, I used. I also have a print for the prop hub. Ed striba has the templet to make the prop, as I had him make mine. the rotax driect 32" combo will give you 60 lbs thrust, mine will be 200 lbs est. they got about 100 ft per min climb with the rotax on the prototype. Well I've got more info about this on the web page, you should read this info. http://www.xmission.com/~that1jim.
. On the prop match, I'm using a hirth 2703 and a 1.8 to 1 redution, the prop is 35", I got lucky and sent the engine info to Irv culver. He drew up a print for a prop to match the power curve and rpm. some how info got out there that it had a 7" tip. try 4.5" tip. Mat the biggest problem running direct drive is the mixture. The 32" prop does NOT load the engine until about 80 to90% rpm. in this mid range it goes super lean. If you stay in this area it will heat up and seize in a matter of a couple min's. Rotax would not even talk to me about running direct drive other then to say don't do it. Also the tip speed is right at mach, .96 most of the horse power is being wasted making noise. (tip stall At least with a redrive the engine is loaded all the time. even with out the prop. The rpm is about half at full throttle, 3660 rpm. and the tip speed is about .5 mach. I too had a cuyuna that I was going to use. but it is NOT desinged to use in a burred pusher config. I hate to tell you this but THROW it away! don't use the cuyuna. It will end up killing you. It will heat up on take off and seize about 200 agl. a gentlemen name Buarl Logan used one on his. I had already looked at the cuyuna and pleaded with buarl not to use it. On his second take off it quit at 200 agl. he then made the mistake of trying to turn 180 back to the runway and spun it in. It broke the fuse in half, but he walked away. he rebuilt the windrose. Acouple of us tried to get him to use a differnt engine. He pushed on. The next summer he went out again. he was also testing out of an airport with forest around it. Tried to sugguest a better place to. This time it happened on the third flight. same 200 agl it seized again. Same thing he tried to turn back. This time it killed him. That's when I got rid of my cuyuna. No matter what engine you use it come's down to this, if you go direct drive, you will only get about 60 lbs thrust and about 100 to if your lucky 300 fpm climb. If you go redrive you will get about 200 lbs thrust, and about 500 fpm. I'm at a base alt of 4500 msl and big mountain's, 100 fpm just won't do it here. I also wanted to cruse it as a airplane. Mine with the battery and elec start, motor mount still came out 3.5 lbs lighter then the cuyuna. well enough pyco babble.
that1jim@xmission.com