Thread: New Product Nine Eagles Sky Surfer.
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Old Sep 20, 2012, 03:37 PM
GLFaria is offline
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"Slow" Sky Surfer motor...

thanks, beautiful photos, I will copy them to a file if you don't mind.

Now, about the "slow" motor on my Sky Surfer:

Some may remember that a couple of weeks ago I decided to replace the motor on my Sky Surfer, as the original one was likely out of order – it would not rev up to speed (see back posts)

At the time I asked in the forum if anyone knew how to remove the motor from this plane and some well-meaning soul suggested I split the front of the fuse (“in reverse”…), and then glue it back after replacing the motor.

Well, when I got the new motor I remembered to ask at my LHS how it was done. The answer? “Easy, just remove the three small screws at the front and pull the motor from the front”! Heck, this plane has a proper motor mount.

So, for the benefit of some other newbie who decides he needs to replace the original motor, here goes a description with pictures.

Ah, and before anyone goes for it, I advise you to read to the end of this post, as I was in for a surprise…

1 – Remove the prop
2 – (photo 1) Remove the three outmost screws from the motor. I suggest that you do this over a flat, even-colored, clear surface – if one of this tiny screws falls on the floor, especially if there is a rug on it, you are bound to do a lot of searching (experience, experience…). A magnetized screwdriver helps.
3 – (photo 2) Disconnect the plug to the ESC. Note: on re-assembling, the two small brass tabs visible on the plug (picture on the right) should look to the same way they were originally seated, for the motor to have the correct polarity.
4 – (photo 3) Remove the motor from the front of the fuse. You can now see the motor mount.
5 – (photo 4) The new motor before assembling
6 – (photo 5) Check how the capacitors on the back of the new motor are positioned. Mine were all spread out, which made it impossible to fully seat the motor on the mount. If that is the case, you must bend the wires so the capacitors can enter the opening on the back of the mount (picture on the right)
7 – (photo 6) Finally, after seating the motor (no force needed!), check it is correctly seated and re-attach it to the mount via the three tiny screws. Screw and tighten evenly - do not start by fully tightening one screw and then trying to tighten the remaining two, this is bound to result in bad distortions. Connect the plug to the ESC, and it’s done.

Finally, do a working test.
Everything done and fine. Right? Well, in my case, wrong!

I assembled the old prop and spinner for a working test, and everything went the same as before – not enough RPM!
When moved by hand the prop seemed to wobble a little, so on a hunch I decided to remove it and put on a new one I had bought at the same time. Surprise, surprise - up to proper revs immediately!!!

The only explanation I can find for this is that the old prop in some way was slipping on the shaft, not enough to fly out front, but enough to not to get to revs (drag, inertia, whatever…) even though the motor accelerated correctly (now, this is a guess, as did not bother to disassemble/reassemble everything back for confirmation; but I’ll keep the old motor – as for the old prop, I binned it).
But I am open to other explanations.

Anyway, if anyone of you feels the prop on you Sky Surfer does not seem to go up to the right RPM, try replacing your prop before buying a new motor. It had already been commented on this thread about this prop slipping – it had happened to me too – but I expected it to slip off, not to slip slow…

And, supermoth, you are right in buying that extra prop. It is quite sturdy, but as shown it may have other, not so obvious shortcomings.

Sorry for longish post, just though it might be useful for someone...

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