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

I had a fun day today.kindda scary

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Old 08-06-2009, 06:39 PM
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zero-cool
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Default I had a fun day today.kindda scary

ok.first flight.viper. sj50 ss muffler 8.5X7.0 18.200 peak backed to 17.500 for flight.all was well.take off was good.throtal servo failed.stuck at wot.no problem just circle until dead stick.30 sec.later one elevator servo failed.every time i pulled up it would kick hard right.no problem. but it was stuck at wot!!!!!I dident know what was going on at the time because it was happening so fast.this thing was out of control!!I dident care about the airframe.I just wanted my jett back in one peice .to make matters worse.I was at a soccor field and there were people around.I was scared of killing someone.thank god it burned through that fuel quick and died.and landed kindda nice on one elevator.I was using some cheap jr servos from a plug and play.I learned my lesson
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Old 08-06-2009, 09:23 PM
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Default RE: I had a fun day today.kindda scary

Zero-Cool indeed! Hope part of the lesson was to fly somewhere safer.
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Old 08-06-2009, 09:54 PM
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Default RE: I had a fun day today.kindda scary

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Old 08-06-2009, 09:55 PM
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Default RE: I had a fun day today.kindda scary


Glad you were able to keep your wits about you. A lesser pilot would have spazzed out.
On some Vipers, you need to shim up the rear of the V tail mounting block about .080'' to get 0/0/0 incidence.
To tell if you need to do this if your elevator has a lot of up trim(not flush with the stab). If so start with 1/16'' and add .020'' after each flight till its even(flush).
This will take some loading off the servos and battery drain.

I've lost a few throttle servos on the Viper too so I thinned a servo arm to give it some flex to keep the vibration for killing it, notice no sharp corners to break at.

What model JR servos were they?
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Old 08-06-2009, 10:04 PM
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Default RE: I had a fun day today.kindda scary

That throttle arm is a work of genius! [8D]
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Old 08-06-2009, 10:13 PM
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Default RE: I had a fun day today.kindda scary

Thanks CP.
There was no room for a zig zag or a coil in the throttle linkage and the distance was so short a plastic push rod would not have helped much, so.....

Zero, don't over tighten the servo's grommets.
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Old 08-07-2009, 09:43 AM
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Default RE: I had a fun day today.kindda scary

You were flying a jet powered viper at a soccer field with people around????? Oh and the first flight no less. Are you out of your mind? That is just stupid, you should pull your head our of your *****, lucky you didnt kill someone or someones kid playing soccer. Fly at an AMA site or at least find a road with no people around.
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Old 08-07-2009, 12:18 PM
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Default RE: I had a fun day today.kindda scary

I agree....I've also done stupid things similar. You've got to have control over the enthusiasm. The best locations I've found for speed flying are giant hay fields, just ditch the landing gear and hand launch. A lot of these fields are owned remotely and only get worked a couple weeks out of the year. These planes can cover some ground, so you need at least 50 acres to fly over that is unpopulated. Where I fly, the adjacent land is farmed with crops, so the safety margin goes up some more.
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