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Old Apr 05, 2009, 10:26 AM
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United States, PA, Bellefonte
Joined Dec 2007
13,249 Posts
Originally Posted by DaDesign
Hi Ron,

I read on RCG about another plane that would not rotate on takeoff and the LG/wheels were to far forward of the CG. They moved the LG "just in front" of the CG and it solved the problem. With this being an ARF you should not need to move the LG. So, I'm thinking CG.
Both of the parties that have owned this ship are long time Nitro RC pilots and I have no worries about CG being a concern, he mentioned that had tried many things with the CG as a part of their troubleshooting.
Originally Posted by DaDesign
This could tell us two things. 1. Tail heavy, CG to far forward. or 2. Something out of line with the thrust line.
Tail heavy was a known issue with this plane, the last owner fortified the firewall <its bulletproof> with epoxy and used heavier motor mounts with helped correct the tail heavy issue.
The Wing and Hro Stab are both in line with each other, off set by 3/4 inch. They are for the most part they have it together. The belly is withing 1/4 of being inline with those surfaces, The top of the nose is 4 inches above the wing line, top of the rudder is 7 inches above the wing line.
Originally Posted by DaDesign
If it were mine I think that I would realign the wing and horizontal stabilizer (along with the motor) with the thrust line. This plane should be straight with NO negative or positive incidence. It should NOT be greater or less than zero.
Everything should be straight on this plane. I would make the wing stright from tip to tip and make it nose heavy for the maiden flight. I would put the battery forward as much as possable to get the nose heavy.
The more I look at this, the less arguement I have for negative incidence, in the picture the wing thrust line is near perfectly square with the firewall. These are not the right motor mounts, just stuck there for reference.
If I where to line things up like the newer revision, this would mean cutting the tail up to align the H Stab, the change to the wing would require cutting the saddle and dropping the back of it. Then my firewall would have an extreme amount of down thrust compared to the corrected thrust lines of the air surfaces.
I like all of your input, the fact is I think you may have a better working knowledge of this then me, I for the most part build from plan and tweak, you have done a little more designs. All input is very welcome!

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