prop advice?
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prop advice?
Hi all. First post on here but have been reading for a while and soaking up everything I can. I raced giant scale breifly in the mid to late 90's, but the cost to be competitive has kinda kept me away. Still, once this racing is in your blood, there's no escaping it. I'm from Ohio and our local club races Vipers, Scat Kats, Doddgers, etc. monthly in the summer. We run K&B 4011's with Macs flow-thru mufflers, Sig 10% fuel, and can run any stock propeller currently on the market. Everyone has been running APC 9.5x6.5 props for a while, kinda follow the leader I guess. I tried some of the other APC's ( 8.5x7.5, 8.75x7, etc.) and know it takes a little longer to spool up, but without a radar gun have no real way to see what kind of gains or losses I am geting in the air aside form what the tach says and the feel when in the grove. I know in giant scale we would try to get as close to a squared prop, like an 8x8, as possible. I currebntly turn about 15,300 RPM on the gound with the APC 9.5x6.5, but know there has got to be a better prop that will make that thing unwind better without bogging it down. I guess I am wondering if there are any suggestions on what prop to run or even if someone can tell me what engine/prop combo's you are running in 424 and what kind of RPM you are getting? Also, I'm curious to know if there is any preferance on a good new/used radar gun that will accurately pick up a quickee to help with the prop testing and not break the bank. I've seen some on E-Bay anywhere from $100 to $1000, but don't want to spend a small fortune. I'm going to go to the NATS this year to scope it out and get some ideas and am planning to build something for 428 this winter. Anyway, it's great to finally find a forum for racers. I should have done this a long time ago! Thanks in advance for any advice.
Adam
Adam
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RE: prop advice?
IN 424 AN APC 9X6 IN A TUNDER TIGER 40 WILL GIVE YOU WITHOUT MODS. 16500 TO 17000 RPMS. I'M TALKING STOCK ENGINES. I HAVE FOUR AND THEY OLD RUN IN THAT RANGE AND THEY ARE HAPPY. PLUS FOR $80 BUCKS YOU CAN'T BEAT THAT.
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RE: prop advice?
In 424 a 9/6apc is the only prop allowed and a TT40 is the only engine allowed, stock engine & muffler except for head shim at least in the southwest. 15% powermaster fuel is the only fuel used. With a head shim change some engines reach 17,500 on good days. The combination gets you around the circuit pretty well.
Denis
Denis
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RE: prop advice?
Thanks for the replies. Since I'm CD at our club races, I'll have to talk to the guys and see how they feel about allowing the TT 40 and maybe that way we can slowly make the switch and that way it will be much easier for anyone wanting to try their hand at 424 and they will already have what they need. Anyone know what the fast times for 424 are right now with that engine/prop combo? Might have to pick up a TT 40 and stick it on my Viper and try the 424 event here in Dayton, OH in August...
I attached a few pics (taken with my crappy phone so excuse the poor quality, lol) of my latest Viper incase anyone is interested...
I attached a few pics (taken with my crappy phone so excuse the poor quality, lol) of my latest Viper incase anyone is interested...
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RE: prop advice?
I thought he was flying the Racer 2.5
Don't get too hung up with RPM in regards to the pylon props. Get the engine in its proper power band in terms of RPM regardless of pitch and run it there. A decent radar, or lap times are really the only good ways of knowing what the plane is doing on the course. RPM is one of the least of the variables I consider.
Don't get too hung up with RPM in regards to the pylon props. Get the engine in its proper power band in terms of RPM regardless of pitch and run it there. A decent radar, or lap times are really the only good ways of knowing what the plane is doing on the course. RPM is one of the least of the variables I consider.