quote:

ORIGINAL: T34RACING

Maybe I can help.

It has been a while, but I think you have the Bridi GR-7 due to the top open hatch on the engine compartment. I am not sure what wing that is but i recall Bridi did lay up a few composite wings.

You may contact Tom Esterday who is in charge of the old RNR Gr-7. He is laying up for the racers. You should be able to get some gear from him. You can go to the USRA website USRAinfo.org.

As to the engine, they do about 150MPH I think with a stock GT-80.

Visit the USRA site for more info.

Kevin

quote:

ORIGINAL: crg13

150 on a strong GT80 is about right, my now dead RnR GR7 was a touch better than that with a very good motor. They do 180 or better on alcohol.

Tom should be able to help you with gear for the airplane. Most guys use Tru Turn spinners, 5" P-51 style. You may have to custom order or modify the cutout depending on which prop you use.

Craig.

quote:



ok all great info, still wondering,
Who can blueprint the Z twin/ either before or after I have bought one
What the best prop choice would be
What exhaust works within the cow.

Can I get a couple of shots of the engine and cooling set up please. I stumbled across a thread/blog where a guy built his own cooling ducts. But I could not see the exit

quote:

ORIGINAL: crg13


Ray,

Blueprint? If you mean just clean up the stock motor a little there are a few guys who can probably give you the basics. If you want it hotrodded there are a couple of guys who do it, Fred French in Texas being one. An alcohol motor may not be too great for sport flying however.

For stock racing we run the APC F1GT prop, it's 20" diameter. It's also not great for sport flying, we usually land deadstick to try and get slow enough. Otherwise just run whatever would suit the GT80.

There's not really an exhaust that works within the GR7 cowl. The exhaust ports are very close to the cowl, so a muffler system would probably have to exit the cowl then re-enter before exiting somewhere else. We run straight exhaust stacks and cut them flush with the cowl.

That thread/blog may have been mine, if it was at RCG and showed the airplane pink before being white. The ducts exit on the underside of the cheek cowls a few inches before they end.

Craig.

quote:






Craig,
no not a full blown race prep, but deffinately something with more umph, on just pump gas.

Considering the cost of props, what is the "best" prop for a mildly prepped gt 80?

Yeah you are right, I did see the plane on RCG, a shot in the California Desert I think. I make it out to Rabbit Dry Lake every now and then. Thanks for all the information, I am pretty excited about this plane. Gonna shoot for a Army Racing Replica Scheme when all done.

Ray

ok all great info, still wondering,
Who can blueprint the Z twin/ either before or after I have bought one
What the best prop choice would be
What exhaust works within the cow.

Can I get a couple of shots of the engine and cooling set up please. I stumbled across a thread/blog where a guy built his own cooling ducts. But I could not see the exit

quote:

ORIGINAL: tschmidt

Ray,

I noticed on your picture the stab is set in the plane upside down. The GR7 has an antihedral stab. You probably already know that but just wanted to let you know just in case.

Nice looking bird the GR7. I scratch built one off my own plans about 12 years ago. It had an 80" wingspan and was powered by a YS120. Unfortunatley it only lasted about 10 flights due to me forgetting to extend my transmitter antenna before takeoff.

Good luck with the build, it should be a beauty when its finished!

Todd Schmidt