Re: 1949 Lawrence Institute of Technology G-1

ARUP Fri Jan 08, 2016 7:51 pm

stuntflyer, the G-1 has straight rudders, tip weight and 'out' thrust. Being a pusher design the prop thrust washer end points into the circle. I use my standard formula of ~25% c.g. of MAC then bell crank pivot 1/4" behind that. The fore lead out rakes back to coincide with c.g at guide. The rear lead out run is normal to fuse. This gives me a decent float to land when the engine quits and I break less props with this set up. I used to put c.g. a little more forward but these little bombs end up being a rock on a string when the engine quit if you know what I mean! Laughing

Thanks for the prop info. I'll have to see what I can obtain. I have a 3 blade prop in there because I was afraid a cut down two blade won't have enough umph. I don't know a whole lot about making a Cox engine speedy so I'll try your ideas out on it! Thanks! Oh yeah... those pusher airplanes are pretty neat! A 'Pushy Cat' would be cool!

stuntflyr Thu Jan 14, 2016 12:39 am

I learned about Cox reedies through some write ups from a few people in the 90's, found that rpm is the key and they get there through short props because they only breath so well. Opening the intake after installing a Tee Dee piston and cylinder, I think 061" or a #61 drill can't remember which, leveling the piston with the deck of the cumbustion chamber by adjusting the cylinder up and down on the block, and using a HC head with a lot of gaskets to start and then adjusting for fuel (a lot of nitro=a lot of gaskets), and props. Once I was pitting for my eldest when he was about 9 so about 1990 in Mouse I, his prop kept getting shorter and the model kept going faster with the wide blade of the Cox props. APC's are probably better but I have limited exprience with them. Only in sport flying like Scale models.
Jimmy Miller's pushers are tops. Loved that guy, a real gentleman. Bohannon's copy was almost as good. Jimmy's was really light, low 500's and he was very slight himself. I was there when he won the Gold Final with it and I know it meant a lot to him. That one would be the best flyer for a model with that delta wing and an easy one to start.
Chris...

stuntflyr Thu Jan 14, 2016 12:42 am

Oh, our Mouse I engines weren't super fast but reliable and started out with NIB Golden Bees with NIB Tee Dee cylinders/piston sets. It was a SoCal guy that wrote the article I used, Paul G. may know whom I'm speaking of.
Chris...

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