Q-500 Racing Discuss AMA 428, AMA 424, and any other variants of Quickie 500 racing

Viper! Near krasch!

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Old 07-11-2008, 04:01 PM
  #1  
jaka
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Default Viper! Near krasch!

Hi!
Was out today again flying my year old Viper powered by a Nelson LS engine.
After the second flight I took it up and cleaned it and noticed a long crack along side the left fuselage side, 1cm from the leading edge of the V-stab.

Took it home and began taking the fuselage apart and noticed that the rear part of the fuselage, in front of the stab had no support at all.
Luckily I had covered the fuselage with 25g glass fiber / laminating epoxy, but this was still not enough...
I was lucky this time!
I will send more pictures how I fixed it later.
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Old 07-11-2008, 04:29 PM
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djlyon
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Default RE: Viper! Near krasch!

Yes you were lucky. Mine broke completely off approaching pylon 1. The viper went straight in and the tail came tumbling down after. We now pull the bottom sheeting off and add stringers. Actually I personally just scratch build now and I know what I have.

Denis
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Old 07-15-2008, 02:46 PM
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jaka
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Default RE: Viper! Near krasch!

Hi!
I removed the stab as well as as I had to fly with some up trim previously.
Lowered the stab at the leading edge 2-3mm. Should be interesting and see if it will improve things.
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Old 07-23-2008, 07:56 PM
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neilrether
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Default RE: Viper! Near krasch!


ORIGINAL: jaka

Hi!
I removed the stab as well as as I had to fly with some up trim previously.
Lowered the stab at the leading edge 2-3mm. Should be interesting and see if it will improve things.
I believe that if you were carring UP trim before...... and you lowered the leading edge of the stab...... then your problem will be worse, rather than better.

That's the way I see it.

Neil
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Old 07-23-2008, 08:35 PM
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fizzwater2
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Default RE: Viper! Near krasch!

No, if you lower the LE of the stab, you effectively put UP trim in the whole stab.. which lets you bring the elevators back to neutral. Less drag without the elevators deflected.

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Old 07-23-2008, 11:09 PM
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Bill Vargas
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Default RE: Viper! Near krasch!


ORIGINAL: fizzwater2

No, if you lower the LE of the stab, you effectively put UP trim in the whole stab.. which lets you bring the elevators back to neutral. Less drag without the elevators deflected.

Correct!

an easy way to look at this is to take a chunk of some balsa sheet,,, forget about the movable surfaces for simplicity here,,, Now tilt the LE down- the plane pitches up and visa versa [sm=shades_smile.gif]


BV
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Old 07-24-2008, 12:27 AM
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bigtrev@xtra.co.nz
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Default RE: Viper! Near krasch!

yes Bill, you are right- interesting example you mention but it is truly as simple as that, regards trevor h, NZ
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