COG?

[ryem3]

I'm running a Voltz 5100 35 c batt and have an ICE 100 and BEC PRO side mounted and am pretty tail heavy. I've moved the batt pretty far forward and I think I'm getting close, but just wondered if anyone else had issues.
I wondered why the bird seemed so slow - it was because it was basically drifting backwards in FFF.

[Daddy B]

Originally Posted by ryem3

I'm running a Voltz 5100 35 c batt and have an ICE 100 and BEC PRO side mounted and am pretty tail heavy. I've moved the batt pretty far forward and I think I'm getting close, but just wondered if anyone else had issues.
I wondered why the bird seemed so slow - it was because it was basically drifting backwards in FFF.

Yep. I have my BEC and ESC mounted at the very front edge of the frame. How are you checking your CG? A simple effective way is to hold the heli sideways by the main blade gripswith the main shaft going straight out from you, parallel to the floor. Make sure that you check it with the tail to the right and left.


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[ryem3]

Indeed, I tried it that way. Tail heavy, no doubt about it. Could really tell just trying to make a dead flat hover, had a slight drift backwards. My ESC and BEC are pretty close to mid-frame - where I've seen many other people mount them.

[chrismechanic]

6000mah lipo and an alloy lipo tray, ice 100 at the front side...bec pro at the rear side...cog is bang on
chris

[ryem3]

I've got the alloy tray too AND the KDE reinforced motor mount, which must add some weight. 6000 - that's a big batt! Never heard of anybody flying those. Guess I'll think about higher C batts next time around or go for the 5300 Gens Ace ones. I think I still have more room in the canopy, so I'm going to keep moving the batt forward to see how close to balanced I can get. This seems likely to be an issue with stock configurations. I just couldn't understand why my heli was just so slow in FFF.

[kdsguy1]

i added 6 oz to the front of the battery mount using tire stick on weights cog dead on

[Way2evl]

Originally Posted by Daddy B

Yep. I have my BEC and ESC mounted at the very front edge of the frame. How are you checking your CG? A simple effective way is to hold the heli sideways by the main blade gripswith the main shaft going straight out from you, parallel to the floor. Make sure that you check it with the tail to the right and left.


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That is a great way, but you should only check it with the tail to the left so your gearing doesn't effect the outcome. The heli will free fall to the left and gearing will hang it up to the right.

I too had a problem with COG. It is a little off. Only thing you can do is push all of your self mounted electronics forward as possible to get a good cog. Adding weight to a heavy helicopter was not an option for me. I rather let the gyro handle the little bit I am off. The right thing to do is move electronics forward as much as possible. If you don't mind weight and rather a good cog, just get bigger batteries. You will have great cog and more flight time. Don't just add weight, worse thing you can do.

[ryem3]

Right, not sure I would add weight either. I was actually thinking of going to 4600 mah batts, but not anymore.

Yeah, the balancing to the side is a pretty obvious one in respect to the OWB.

I may add a couple of clicks of TX trim.

I'm just surprised it is out as much as it is. There's no way you could really fly with a 3000mah batt and have anything close to balanced.

[Daddy B]

Originally Posted by Way2evl

That is a great way, but you should only check it with the tail to the left so your gearing doesn't effect the outcome. The heli will free fall to the left and gearing will hang it up to the right.

I too had a problem with COG. It is a little off. Only thing you can do is push all of your self mounted electronics forward as possible to get a good cog. Adding weight to a heavy helicopter was not an option for me. I rather let the gyro handle the little bit I am off. The right thing to do is move electronics forward as much as possible. If you don't mind weight and rather a good cog, just get bigger batteries. You will have great cog and more flight time. Don't just add weight, worse thing you can do.

That's a good call. Now that I think of it, I check it both directions so that I can find the side that doesn't get caught by the OWB. Good catch.


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[chrismechanic]

Originally Posted by ryem3

I've got the alloy tray too AND the KDE reinforced motor mount, which must add some weight. 6000 - that's a big batt! Never heard of anybody flying those. Guess I'll think about higher C batts next time around or go for the 5300 Gens Ace ones. I think I still have more room in the canopy, so I'm going to keep moving the batt forward to see how close to balanced I can get. This seems likely to be an issue with stock configurations. I just couldn't understand why my heli was just so slow in FFF.

yer the 6000 just fits under the canopy...canopy pretty much is sitting on the lipo .
i wouldnt have thought the cog would affect the fff in such a manner? what pitch is your heli set to?
my 550 is faster than the planes at my local field...
chris

[ryem3]

Well, as I tip the cyclic forward to FF, the cyclic was drifting backwards, basically slowing it down. Typically, you give the cyclic input and it maintains that attitude with minor corrections. I kept needing to make serious forward cyclic inputs to get any decent speed. Hopefully it will be much improved. Haven't had much chance to test it out after the discovery.

[chrismechanic]

sounds like it could be pitching up...you should be able to get rid of that in the settings of whatever fbl controller you have...
chris