I've been trying to get a response from Nitro Models regarding the CG on the E-3D model.

It came in two weeks ago, and I got it finished last week, and went together fine. I put it together per the instructions, and all was well up till time to set the CG.

They say it should be 2.2 inches aft of the leading edge. On most of the planes I've built so far, you use this measurment at the root next to the fuselage. When I set it on the Robart balancer, set to this measurement, it is so tailheavy that I need 6 oz. of lead as far forward as possible to get it to balance.

If I mark the 2.2 inches at the wing tip, it balances slightly noseheavy with about 1/2 oz of lead as far forward as possible.

Big difference - and scary. I know that the CG is normally about 1/3 of the distance back from the Leading edge at the Fuselage. Which is where it comes closer with the measurement at the wing tip. But the plans do not state where this CG is measured from, other than the leading edge. Not at the root, or where in the overall length of the wing.

I've phoned Nitro Models, Sent Emails, and have gotten no response except for one that asked for the order number. Which I dont keep after the package arrives and is in one piece. So I have a plane that If I launch it, might crash immediately. And the order number has no bearing on my problem anyway.

If anybody in this forum hs any idea about this, I surely would appreciate it. Apparently the Vendor is not interested in helping me. And I was going to try the Yak they have, but decided to spend the extra and get another Hyperion Yak, they fly great, and at least if I have a problem they respond with help.

Which plane is this?

I don't see it up on the web page.

Could you post a link?

(Edit: Never mind... I forgot to look at the Electrics )

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I have a bunch of Nitroplanes airplanes and every one has had the C.G. measurement either against the fuselage or in the case of biplanes, and a few monoplanes, measured from the mid point of the wing, leading edge front.

I would not go by the wing tips.

Better to be nose heavy and remove weight as needed.

Remember that shifting the engine a 1/4" forward can obviate the need for much of the extra weight...

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Note: Similiar models in G3 have the C.G. fairly close to the fuselage measurement you are stating.

You could always check with one of the on-line C.G. calculators.

I think I got it, and it has to be using the distance at the wing tips.

I used an online calculator and it said to have CG at 3 7/8 inches at the root. Which is exactly where it would be using the 2.2 at the wingtips. A friend has the QQ Brio 10, which is close to the same size etc. and his instructions say 3 7/8 at the root.

It takes 6 ounces of lead to get it even close to balanced at 2.2 inches at the root. On a 20 ounce plane I think this would not work. But it only takes 3/4 ounce to make it slightly noseheavy if I use the 3 7/8 that the calculator gives. And the 1/4 inch extension of the motor wouldn't make up for 6 ounces.


So If the weather clears, I'll try it and hope for the best. It's just a pain when the instructions are not very clear (made in the Far East) , and the Vendor is not available to give advice. Probably the last order they get from me. Asssuming that they even know what the CG should be, or care if I order again.

NP probably doesn't know the answer to your question, they are more of a clearning house, hence the low prices.

The instructions typify most asian ARF's, so going elsewhere doesn't really buy you much in terms of the instructions (with a few exceptions....)

You should see what the many of the CMP and most of the KMP ARF's come with if you thing this is bad.

A good rule of thumb is to always assume that the instructions may be in error.

GP, Horizon and other "big boys" also frequently produce manuals where simple things like the C.G. is totally off...

Fortunately I've searched here before flying planes from those manufacturers to find this out.

So all of this is endemic and not isolated to NP not that this is an excuse...

If they have no idea about this, I would have felt more comfortable just to have them tell me they have no idea.

I'm just upset because they have not responded in any way to my Phone calls and Email messages, and it's 2 weeks now.

I can accept any reasonable explanation, but no response is in-excusable.

Please use this it will give you the exact CG piont of your plane, Good luck with the maiden ..

http://www.coloradogliders.com/cente...calculator.htm

I went there, and used their formula. Came out at 3.5 inches back at the root. The plans call for 2.2 inches. Big difference. I have it set at 3.5 and it only took 3/4 ounce to make it slightly nose heavy at that measurement. Going to try it tommorrow if the weather permits, but hate to destroy a nice looking plane if I'm wrong.

The real thing is not getting some sort of response from NP. Even if they were to tell me they had no clue, but to ignore the phone calls and Emails is poor service. And that's my real beef.

Something which they should note.

Nitrostaff?