Lengthen the nose?

[AndrésMtnez]

Hi

I´m building a plane where I can´t find the CG without adding too much weight to the nose, and I´m thinking about lengthen the nose to be able to remove some lead.

What would change of the flight behaviour if I do it?


Thanks
Andres

[Ollie]

Think better. Make the tail lighter. Then you don't make the nose longer. Save every gram in the tail is better than saving three or four grams of lead. It is better to rebuild the tail lighter (happy) than the nose longer (yuck).

[vintage1]

Only possible downside is adding lateral area forward may make the model unstable in Thats easy to fix. Bigger rudder/fin/tailplane.

[olmod]

I would need to see the model and know the size :)

[yoyoML]

Or enlarge the horizontal stab/shrink the main wing.

Pictures, please.

[AndrésMtnez]

Thanks all, but it´s not a scratch build, only a gws Tiger Moth 400 that I´m preparing for FPV flying. I want to place the camera in the cockpit for a real view, but this airframe is already from stock a bit tail heavy and adding 60g of the camera+servos behind the cg doesn´t help :rolleyes:


I wouldn´t like adding 30-40 or even more lead, and if lenghtening the nose I can save some I´d love the view from the cockpit ;)


The rudder and elevator surfaces are pretty generous, so I think if that may be the only concern I don´t worry about that.

No more cons?

[olmod]

I dont think it will make that muchof a difference ,maybe only to the fact that if you have set thrust angles they may need less.

[yoyoML]

Thanks all, but it´s not a scratch build, only a gws Tiger Moth 400 that I´m preparing for FPV flying. I want to place the camera in the cockpit for a real view, but this airframe is already from stock a bit tail heavy and adding 60g of the camera+servos behind the cg doesn´t help :rolleyes:


I wouldn´t like adding 30-40 or even more lead, and if lenghtening the nose I can save some I´d love the view from the cockpit ;)


The rudder and elevator surfaces are pretty generous, so I think if that may be the only concern I don´t worry about that.

No more cons?

Please just enlarge the horizontal stab/elevator instead of lengthening nose and adding weight. You'll have more wing area without much added weight, and still make the plane stable. Besides your view out of cockpit won't be blocked by a longer nose :rolleyes:

Calculate how much tail surface you need, to get a neutral point behind your current cg (with 60g of camera).

[vintage1]

Please just enlarge the horizontal stab/elevator instead of lengthening nose and adding weight. You'll have more wing area without much added weight, and still make the plane stable. Besides your view out of cockpit won't be blocked by a longer nose :rolleyes:

Calculate how much tail surface you need, to get a neutral point behind your current cg (with 60g of camera).

That is actually a pretty good idea.

[AndrésMtnez]

Please just enlarge the horizontal stab/elevator instead of lengthening nose and adding weight. You'll have more wing area without much added weight, and still make the plane stable. Besides your view out of cockpit won't be blocked by a longer nose :rolleyes:

Calculate how much tail surface you need, to get a neutral point behind your current cg (with 60g of camera).


So if I enlarge the horizontal stab, even if I´m adding weight to the tail, the behaviour would improve and wouldn´t matter a even more backward cg?


I guess you´re refering to the fixed part of the stab.

[Ollie]

Find the best structure for the stab so that it's weight is minimized. No any old structure. The stab area is enough so that it shifts the neutral point so that the CG shifts aft while stable in pitch. See:
http://www.geistware.com/rcmodeling/cg_super_calc.htm