Extreme Speed Prop Planes Discuss the need for speed with fast prop planes (Screamin Demon, Diamond Dust, Shrikes or any REAL sound breakin'''' plane)

GP Viper 500 - flight report

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Old 08-23-2006, 08:03 AM
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nexxa
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Default GP Viper 500 - flight report

Not really an extreme plane, but fast.
Return to old love. It's my second one. With the first one I made a mid-air.

OS.46 FX, 20% nitro.
APC 9X7 - not enough thrust. Can't go faster than 87mph/h on straight line (15 900 rpm/ground). But the engine sound was awesome.
APC 9X8 - not better
APC 10X7 and 10X8 - too much thrust. slower but cool.

APC 9.5X6 - my better match. 105mph straight line . Very good vertical, impressive acceleration.

Today, I will try it with 9.5X7 on 30% nitro.

Another think. I use V-Tail mixing on my transmitter, and I install a micro servo to the tail with a small tail wheel to control the plane on runway. Not my better Hop-up idea. In the air when I apply Up or down elevator, the tail wheel is moving right or left. It comes from the V-Tail mixing (elevator/rudder) channel. The tail wheel acts like a small rudder! The plane flys like an un-trim plane. Not a big deal, but when I came out from a big dive at 10 feet over the runway, I becomes visible!
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Old 08-23-2006, 08:33 AM
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daven
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Default RE: GP Viper 500 - flight report

Looks great, I would suggest a couple pylon props for that combo.

Both the 8.8"x 8.75 and 9 1/2" x 7.5NN work well and should get you up closer to 120 mph.

If you want max speed an 8.8" x 9.5 works well on a long pass, but is tough to get off the ground and loses a ton of speed in a hard turn.
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Old 08-23-2006, 11:47 AM
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Default RE: GP Viper 500 - flight report

Sounds good...I have a Predator and have a TT46 pro and a tuned pipe turning a 10*7 and boy does it move at about 115-120 on the straight. Corners like a scared cat on rails. Its fun to keep it close between two trees at either end of our field about 100 m appart flying low figure of 8's. Nice plane enjoy. I may even pick up the speed and use a 8*9 or 8*10 and see how fast she is. The 10*7 gets it off the ground and up vertical very quick. Nice to push the top end speed now.
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Old 08-24-2006, 08:51 AM
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nexxa
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Default RE: GP Viper 500 - flight report

This weekend I will test it with this prop 9 1/2" x 7.5NN. I order it yesterday.

Yesterday, I try my little OS.46 with Wildcat 18% oil / 30% nitro an a cold plug. Wow! Finally I got all the power from my .46. I run at peak RPM (16 200) an APC 9.5X7. I make it rich a little to reduce the RPM to 15 800, for security. I saw the difference in the air... love that



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