Sunday, January 15, 2012

Motor Mods

Hello all, I discovered that my new Wild Hawk motor is not performing as well as I expected.  I wondered why and after some research I found that others who had made similar modifications also upped the prop size from the stock 5x5 to 6x4 to 6x5.  So, that is my next update.

Ok, ok, I know that the Turnigy 2628/10 1400Kvm motor is a bit under speed for this modification, but for now, its what I've got.

Needs 2 or 3 more mm
Others were successfully using these props on their Wild Hawks so I did not think it would be a big deal and picked up a few of the size I mentioned above.  I tried to install one of these 6" diameter props but, it hit the tail boom on my plane, so I needed an explanation of what I had done wrong and a solution.

After some correspondence with Fishbonez and NJSwede, they said it should have fit, but if it's only a few mm, I could just cut out the foam.  So back to take a look at things.

After looking at my situation, I decided that I should be able to move the screw holes for my motor up enough to create the needed clearance.  After unbolting the motor, this is the view I had showing the alignment marks I used to locate the original mounting holes.

New holes marked and drilled
Ready to mark the new holes
 I added these lines to help layout the new holes directly above those that are already there.  It looked like I should be able to safely move the holes straight up about 6mm.  I marked them out and pilot drilled them with a 1/16" drill bit.

It fits!
Just enough clearance
  Fitting on the motor shows that the clearance is just right.  This is probably closer to the shaft location of the original motor than my original modified location.  This would explain why this prop did not work before but does now.

Original motor location, face view
New location. You can see the old holes
 I like this solution because it was a lot easier than another option I was considering (building a new firewall to add on on top of this one) and I did not have to remove any foam for clearance.  Removing foam for clearance might have actually been the easiest solution, but I've had bad experiences with doing this before on another plane and so I really did not want to do this again.

Now I'm ready to test out those larger props and see if I get any more performance over the old 5x5 prop without burning up the motor or speed controller.  I'll post again with the results.


The 7" has much broader blades
I really like these APC electric props
I have since flown this configuration and found that this APC 6x5 prop, while much better than stock, was not performing as I had hoped.  I have since taken a 7x5 and cut it down to 6" in diameter and carefully trimmed and re-balanced.  As these APV props have a much broader blase mid section they grab much more air than others.  Most other props have the same blade width for a series of props and the only thing that changes is the length.

I now have all the power that I need and am seeing the performance of this torqueie 1400KV outrunner.  I have also tried this with an 8x4 and with similar results.  See my Wild Hawk vs Wind post for how well this configuration did.

Thanks for stopping by my blog and please post comments, good or bad.  Be sure to come back and check for future posts.

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Mr. Clean