Thread: New Product E-Flite UMX Carbon Cub SS
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Old Jan 26, 2013, 07:01 PM
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Originally Posted by Audioguru View Post
Has anybody tested that cheap nanotech battery?
Horizon Hobby do not have the TP 325mAh 65C battery yet but it will cost 3 times more than the Chinese one.
Yeah, a number of people have done battery load tests & static RPM tests with the popular UMX packs - including me. Nothing comes close to the TP 325 65c packs. Not even the new Hyperion VX 500 35c packs - which are the second-best performers, followed by the Hyp VX 400 35c packs. And then there's the difference in cycle-life. The Nanos won't last for hundreds of cycles like the Hyp & TP packs do.

If you want to see some recent UMX pack test data, check out the UMX MiG 15 mod thread. You'll have to dig a few pages, but someone posted an excellent test-report w/discharge graphs, comparing a number of the popular packs at various currents.

Originally Posted by Audioguru View Post
The propellor spins to the right so the torque of the motor causes the entire airplane to roll to the left. Add a little right rudder and/or right aileron to the linkages.
There is a proper way to flight-trim a plane, and the steps must be followed in the correct order. Here's the trimming section of the CC handling checklist I put together awhile back:

1) Visually inspect the alignment of all flying surfaces with respect to the fuselage & each other. Also check the alignment of the tailwheel with respect to the rudder. For best results, any visible misalignment should be corrected before proceeding further.

2) Be sure that the plane remains motionless during the first 5 seconds after connecting the battery. The plane can be on its back or in any other position during initialization, provided that it remains motionless during the process. Move the aileron pushrods to the second hole out. Move the rudder & elevator pushrods to the innermost or second hole out. If the plane seems overly sensitive, try adding a bit of expo, rather than reducing throw - as there will be times when full control authority is needed.

Mechanically trim the plane by adjusting the pushrod U-bends so that little, if any tx trim is required for straight & level flight in zero wind at 50-75% throttle. AS3X interprets excessive trim (more than a few clicks) as command inputs, so tx trim should be used sparingly. Also - never use sub-trims with AS3X. Ideally, flight-trimming should be done in dead-calm conditions. The next best alternative would be flying directly away from yourself into a light, but steady headwind.

4) Measure the CG, then perform an in-flight CG test & adjust as needed: If you need up-elevator trim (mechanical or on the tx) for level flight at 50-75% throttle, the plane is overly nose-heavy. If the nose drops like a rock in turns and/or when power is reduced, the plane is overly nose-heavy. If the plane is trimmed for level flight at 50-75% throttle and it balloons when you go to full power, it's overly nose-heavy. If the nose comes up or doesn't drop at all when you cut the power, it's very tail-heavy. If the plane seems to be overly sensitive to micro-turbulence, it's also tail-heavy. (You can actually hear the difference by listening to the sound of AS3X working the servos.) When the CG is about right, the nose should drop slightly as the plane slows after the throttle is pulled back. If the plane is trimmed for level flight @ 50-75% throttle and you go to full power, the plane should gain altitude, but the nose should come up only slightly, if at all. Measure the CG again after the final adjustment for future reference.

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Last edited by turboparker; Jan 27, 2013 at 08:02 AM.
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