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May 15, 2017, 04:01 PM
Live Free and Fly
Quote:
Originally Posted by moti007
with 2X5200 4S its 85mm with pantilt and fpv camera and HDruncam
Thanks. I'm running a large Cobra motor and 12g servos in the tail so that's probably where the extra weight is coming from. I can't get it to balance at 85mm unless I move the 2x 5200 4S into the nose. Maybe it's time to get a 16,000mAh battery.
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May 20, 2017, 03:51 PM
Registered User
Yes 16 is the best...
May 20, 2017, 04:38 PM
Live Free and Fly
Took the maiden flight today. I believe the factory CG of ~85mm is a bit off. I think after seeing how it flew on my 35+ minute flight I will play around with the CG. It looked a bit tail heavy when balancing on the ground, but flew like it was a bit nose heavy, always requiring a bit of up elevator. I will run some calculations, take another test flight and report.

Other than that, it flew beautifully. Although there was a bit of blustery wind up there, it really didn't affect it at all. Just shrugged it off and was very stable.
May 20, 2017, 10:38 PM
Live Free and Fly

Factory CG wrong?


I took the time to input the Sabre specs (as good as I could measure them) into the eCalc CG calculator and it came up with the correct CG around 10mm further away from the wing LE. If anyone wants to do the same to verify my results, feel free.

For my maiden flight I balanced it on the factory CG of ~85mm and on the ground it looked tail heavy but flew definitely nose heavy. Now I know why.

Here's the link to the Sabre calculations I came up with.
May 21, 2017, 12:59 AM
Registered User
Thanks bmw111 ,
You fly with thus cg?
May 21, 2017, 09:12 AM
Live Free and Fly
Quote:
Originally Posted by moti007
Thanks bmw111 ,
You fly with thus cg?
Not yet. I will report on my results with the new CG after my next flight.
Jun 04, 2017, 05:07 PM
Live Free and Fly

Revised CG


I've flown two flights with revised CG, one at 95 mm from wing leading edge, and the second flight at 97 mm from wing leading edge. With my plane's current setup, 97 mm performs best. I have a Yi action camera with BEC and 1100mAh 3S battery in the nose, Mobius and flight camera on a ProPan at the pan servo mounting point, and running two 5200mAh 4S MultiStar batteries.

I have a 16000mAh MultiStar on order, when I install that I will probably remove the Yi action camera/BEC/battery. That will take out quite a bit of weight from the nose, so I may have to adjust CG again. But as of right now, it flies great at 97 mm from the wing leading edge. And when I say "great," I mean no mechanical elevator trim, flying straight and level at 50% throttle.
Jun 04, 2017, 06:04 PM
Registered User
smoothvirus's Avatar
Quote:
Originally Posted by bmw111
I have a 16000mAh MultiStar on order, when I install that I will probably remove the Yi action camera/BEC/battery. That will take out quite a bit of weight from the nose, so I may have to adjust CG again. But as of right now, it flies great at 97 mm from the wing leading edge. And when I say "great," I mean no mechanical elevator trim, flying straight and level at 50% throttle.
I have done some test flights with a 16000mAh 4s MultiStar installed in mine, it flies fine. It's a little heavy and the climb out is more shallow but it handles OK.
Jun 05, 2017, 04:06 AM
Registered User
someone use the landing gear?