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What fight charactoristics would you expect from a nose heavy plan?

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What fight charactoristics would you expect from a nose heavy plan?

Old 07-20-2005, 09:26 PM
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Quicksdraw MaGraw
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Default What fight charactoristics would you expect from a nose heavy plan?

I curious about generalities during flight and landing.
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Old 07-20-2005, 09:42 PM
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hattend
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Default RE: What fight charactoristics would you expect from a nose heavy plan?

1. Sluggish in pitch response
2. Poor inverted performance
3. Unable to hold nose up when slowed for landing (run out of elevator)
4. major trim changes as speed increase or decreases
5. Nose drops excessively when plane is rolled

Don
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Old 07-20-2005, 10:02 PM
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Default RE: What fight charactoristics would you expect from a nose heavy plan?

Basically the stability improves - but as the model slows - the above notations are correct.
On a fast model the bias to "nose heavy " is desireable.
It increases predictability
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Old 07-20-2005, 10:49 PM
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Quicksdraw MaGraw
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Default RE: What fight charactoristics would you expect from a nose heavy plan?

The plane I am currently struggling with tends to snap when I'm trying to land. Do you think I could expect this to improve if I move some weight aft? The only thing listed by Hattend that seems familiar is the running out of elevator but that is slight.
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Old 07-20-2005, 11:08 PM
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Default RE: What fight charactoristics would you expect from a nose heavy plan?

What plane is it? You could simply be trying to fly too slowly.

Don
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Old 07-21-2005, 12:04 AM
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Default RE: What fight charactoristics would you expect from a nose heavy plan?

It's Phoenix Sukhoi. Last time it snapped it was dead stick. I was almost in safe....... One of the guys that witnessed it said he thought I had enough speed.
I'm going to find out tomorrow. I moved a little weight back. I'll see how it flies........
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Old 07-21-2005, 12:10 AM
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Default RE: What fight charactoristics would you expect from a nose heavy plan?

If moving the CG back doesn't help, try reflexing the ailerons slightly. Most aerobatic planes have a tendency to snap when slow...ranging from mild to wild.

I had a Modeltech CAP-21 (aka SNAP-21) and I had to land it hot... hot... hot.

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Old 07-21-2005, 08:43 AM
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Default RE: What fight charactoristics would you expect from a nose heavy plan?

Likely the wing loading is simply very high
Here is the sad fact of most ARFS like this
They are simply too heavy for their size.
So to control the model - speed has to ALWAYS be higher -for any maneuver
Only two things count
weight to size and power to weight - In these models, all the rest of the "trimming" of ailerons/flaps airfoils etc.. is a distant second.
Shifting the CG aft will only increase the problems.
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Old 07-21-2005, 11:02 AM
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Default RE: What fight charactoristics would you expect from a nose heavy plan?

I found in 99% of my airplanes over the years, the designer places the CG a little nose-heavy "just to be on the safe side"; I use that as a forward extreme and usually move back from there until the plane is trimmed upright/inverted/knife edge without being overly touchy on the elevator. IMHO flying nose-heavy requires up trim, which increases the angle of incidence of the wing, bringing it closer to a stall condition (raising the stall speed). OK everybody, take your best shot!....Jim
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Old 07-21-2005, 12:27 PM
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Default RE: What fight charactoristics would you expect from a nose heavy plan?

I'm inclined to agree with the too heavy option.

Another bandaid you can try is adding upper suface turbulator strips to the outer 1/3 of the span on each panel. Try a temporary cheap fix by adding a stip 1/8 wide by 3 layers deep of masking tape or electrical tape to the airfoil about 10 to 15% back from the leading edge. The turbulators should soften and delay the tip stall that is causing your snap roll problem.

Of course the model may not snap roll on command as easilly. If you find it helps the landings but affects the aerobatics too much then make it shorter by trimming some off the inside or outside until you get the blend you want. If it doesn't seem to help at all move it forward to the 10% location and try again if you started with it back further. If it still doesn't help then add helium to the model....
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Old 07-21-2005, 01:31 PM
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Default RE: What fight charactoristics would you expect from a nose heavy plan?

HEAVEN'S no, the last thing you want to do to a wing dropper is move the CG back.
If anything, add weight to the nose and make your landings a little faster.


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Old 07-21-2005, 01:43 PM
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Default RE: What fight charactoristics would you expect from a nose heavy plan?

Or, on the next snap where you have to make repairs, peel the covering off the wing and recontour the leading edges. Sharpen the LE at the root transitioning to a big generous radius at the tips. That'll help.

Don
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Old 07-21-2005, 06:05 PM
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Quicksdraw MaGraw
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Default RE: What fight charactoristics would you expect from a nose heavy plan?

Wow you guys have some great input.

So earlier in the week while repairing the plane I found the lead nose weight many have referred to. Well the plane was nose heavy so I removed it. I thought that while I was working I would try to get near the manufactures CG. The lead in the nose was 2.375 oz. and I added about an oz to the tail. I thought this would be enough as relative to the CG I had moved more than 5 oz aft ( it was still nose heavy). Well after a little trim the plane flew every poorly. Like it always wanted to perform a new maneuver to send it earth bound. And it consistantly wanted to rise out of its landing glide. Upon consult with one of the field vets I removed the tail weight I had added. It's much better now, everything about it has more confidence and the landings are flat and controllable.

So all in all I ended up with a plane thats 2 ozs lighter and have experienced first hand how to recognize and handle CG problems!
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