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

Diamond Dust problem

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Old 05-18-2006, 12:25 PM
  #1  
Lee Cox
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Default Diamond Dust problem

Hi Guys,
I have a DD with Jett 40 fire, for the life of me i can not trim the plane for level flight, as soon as i hit the throttle she climbs to the point that i am pushing the stick almost fully forward, if i do trim the elivator for high speed as soon as i come off the throttle she dives and i have little elivator to flare and land.
I have played with the C.G, and have added a couple of shims at the rear of the engine to add some down thrust, but this has not changed the climbing at full throttle.
Is this typical of a DD???
Other than that a great fun plane.
Any advice much appreciated thanks guys.
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Old 05-18-2006, 02:23 PM
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Mike Connor
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Default RE: Diamond Dust problem

This is not normal for a Dust. It should fly great with the engine thrust line at 0x0. My first Dust, after 90+ flights and several repairs, developed a violent pitch up and right when a certain speed was hit. Mine was an airframe issue (from several crashes). If yours is new then something is not right with the build. I had to tear off the bottom covering to inspect and repair but on a Dust it is quick and simple. Good luck.
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Old 05-18-2006, 04:02 PM
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Default RE: Diamond Dust problem

Sure sounds like the tips might be washed out (TE high) - if you sight the wing carefully can you see any twist in the wing panels? Did you have any roll problems or just pitch? With the ailerons trimmed for no roll are they parallel with each other?

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Old 05-19-2006, 04:38 AM
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Lee Cox
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Default RE: Diamond Dust problem

Thanks for replying guys, it was a second hand Dust that i bought, i did notice a twist in the left TE which i ironed out!
I will have another good look to see if it has any more warps/twists. Is it worth recovering and checking for any damage/poor construction inside.When trimed the left Aileron is a few mm lower than the right!!

I think you guys have put me on the right track, thanks again!
Lee
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Old 05-19-2006, 12:00 PM
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Mike Connor
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Default RE: Diamond Dust problem


ORIGINAL: Lee Cox

Is it worth recovering and checking for any damage/poor construction inside.
Lee
The Dust may not have been built straight. I would think you could see the problem just holding the plane out in front of you. If you deceide to inspect inside just cut the bottom covering off. I was able to recover the bottom with one piece of covering in about 15 minutes. Landing damage will make this necessary every so often.
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Old 05-19-2006, 12:22 PM
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Lee Cox
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Default RE: Diamond Dust problem

Yep i suspect this is the problem, lets face it there isnt much else it could be!!
Thanks again

Lee
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Old 05-19-2006, 12:45 PM
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Default RE: Diamond Dust problem

let us know if the ironing straighten things out. I am curious, good luck, I hope it worked.



RICH
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Old 05-19-2006, 07:59 PM
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Default RE: Diamond Dust problem

Mike, not owning a DD yet but is it a sound frame or is it easily subject to warping a tad to cause that? That guy who sheeted his seems to get decent speed out of it.
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Old 05-19-2006, 11:29 PM
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Mike Connor
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Default RE: Diamond Dust problem


ORIGINAL: Cyclic Hardover

Mike, not owning a DD yet but is it a sound frame or is it easily subject to warping a tad to cause that? That guy who sheeted his seems to get decent speed out of it.
I have built two and both were straight. The instructions call for putting the airframe together with rubber bands before gluing. I made sure it was straight on a flat table before gluing and both were straight. A little care while covering is needed to make sure it stays straight. Sheeting may be OK if it does not add too much weight but I have not tried it. The Dust is cheap and the build time is in hours, not weeks. The WOW factor is high so it is time to get started.
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Old 05-20-2006, 12:22 AM
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Default RE: Diamond Dust problem

I am currently putting mine together and going over the instructions ..glueing starts with step 11 on ward as you go... Mike, do you have different set of instructions or is that just done by preference to glue everything last?
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Old 05-20-2006, 08:24 AM
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Mike Connor
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ORIGINAL: HaveBlue

I am currently putting mine together and going over the instructions ..glueing starts with step 11 on ward as you go... Mike, do you have different set of instructions or is that just done by preference to glue everything last?
Except for a drop of glue on the rear spar and one other place, before gluing you assemble the spars, ribs, engine mount and trailing edge. I guess that is just a partial assembly I am out of town for a few day. Enjoy your weekend.
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Old 05-20-2006, 12:32 PM
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Default RE: Diamond Dust problem

The only other thing I can think of is that if the CG is too far forward, you will be flying around with UP in the elevons........as soon as you add more power, the tendency will be for the plane to climb. If the plane flares OK when it is dead stick and ready to touch down, then it probably isn't the CG. If you have a straight plane that is trimmed for level flight, take it up and put it into a 45 degree dive and let go of the stick. If it tucks under, it is nose heavy, if it tries to pull out of the dive, it is tail heavy. Gotta be working with a straight plane for this test to be meaningful. Shouldn't be too hard to block the plane up on a flat table and give it a good look with a ruler.
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