Tail Heavy

[shails]

My swash is level at low-mid-high stick. However the tail is heavy and the tail keeps on dipping in hover and the nose keeps on falling in invert. I am using a 7.4V 2500 mah lipo and have tried to mover it as forward as possible to move the CG forward. However it seems that nothing is working.

Can anyone tell me what wrong am i doing?

[Ross Lawton]

Hi Shails,

Could you provide any pictures and details of your setup?

If the tail is dropping in a upright hover and the nose is dropping when inverted it would suggest that there is something else causing this, as in a tail heavy situation when inverted the tail would continue to drop as in the upright hover situation.

If anything it sounds like you have a small amount of rear elevator cyclic offset in your swashplate, as this would explain the tail dipping when in an upright hover and also explain the nose dropping when inverted.

Couple of things i would check:

Firstly, has the machine been crashed recently? If so then check the central elevator bellcrank arm (610-226), as in a crash this can be damahed and it can move on the pivot shaft. Next, I would check the mechanical setup just to make sure that there is no rear elevator cyclic. A good swash level tool like the Trueblood or FBL Rotors swash tool makes checking this a simple and accurate job. Even if the swash looks level it could be very slightly off and this could cause the problem your experiencing.

Hope this helps and let us know how you go,
Cheers
Ross

[shails]

I stand corrected. My mistake, the tail drops even in invert.

No, the Heli has not crashed ever. I am using a FBL rotor levelling tool and have rechecked a number of times. The swash is perfect level.

Applying a few forward clicks on the elevator and nose starts dropping. Unable to find the sweet spot. Will post some pictures of my setup.

[Ross Lawton]

If it is doing the same both upright and inverted then that would rule out any discrepancy in the swash alignment.

The N5/N5C does like a light setup, yet depending on your equipment you could have an exceptionally light setup which means you could benefit from using a slightly larger capacity lipo battery for powering your electronics.

A good test for balance is to unfold the blades, keeping the canopy on and tip the heli on it's side, this will show if the heli is nose or tail heavy, if this is a balance issue then in your case the tail will drop. Try swapping the battery out for a higher capacity one and retry this test. What your aiming for is no matter which orientation you turn the helicopter mechanics into it will stay staionary without any or very little movement.

Try the above and let me know how you go,
Cheers,
Ross

[Greg Jackson]

I didn't see what FBL unit you are using.  Check you endpoints and make sure there wash any trim applied during setup.  That could be it.  Also, depending on the fbl unit what tape did you use.

[shails]

Ross I did what you told and the tail drops. Guess I will need to use a larger battery. Don't have one yet but will need to buy it. Would a 4400 mah suffice?

[Flat Eric]

I run a 5000mah lipo on mine and cog is perfect 

[Ross Lawton]

Depends on what equipment you are using, the lighter the equipment the larger the battery you can run. I would probably increase the pack size to around 3600mah (give or take) and see how you go. If you go too big then you could find that you end up with a nose heavy situation.

Hope this helps, and let us know how you go.
Cheers
Ross

[birddawgg]

Man those are big packs ya'll are running my equipment must retard heavy. Mine COG's perfect with an 1800mah pack and a half tank of fuel. I only run the 1800's because that's what the manual called for.

[Kevin Dalrymple]

I am running the Volts 2500 packs and it is perfect with a 1/2 tank. I am running a 750 and a switch glo.