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Feb 19, 2011, 05:55 PM
Registered User
rcpilot23's Avatar
I have bought the Hobby City brand Turnigy Nano-Tech 4S 3000 25 C lipos and they work great. Cost me $95 for 2 lipos with UPS shipping
Eflite 4S 2800 pack is around $130 here in Perth Western Australia.

After about 15 flights my motor started to make a terrible noise.

Here is the video

Eflite Carbon Z Yak Motor problem (0 min 32 sec)



I was very impressed with Model Flight in South Australia who are the distributors. After I did the video I removed the motor and found the motor mount plate was broken in 2 places. I sent the motor and motor plate back to Modelflight on the Tuesday afternoon with an overnight delivery parcel.
I got back a new motor and motor mount Thursday lunchtime !!!

Can't beat that excellent service. I suspect the noise was the motor mount being broken and the motor shaking as a result. Matthew from Model Flight said the motor looked ok but he still sent me a new motor to be sure.

Dont get that support from Hobby City or even my LHS.

I also had to reglue the magnetic mounts back into the plane and hatch as they fell off. Just used medium CA and kicker so was a quick and easy fix.

Very happy with this plane. !!
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Feb 25, 2011, 10:26 AM
Registered User
max-nix's Avatar
Check the propeller balance, mine was extremely out of balance as if the prop shaft hole was drilled off the center line. the prop balanced horizontally on my balancer but would always rest with the heavy side of the hub down. (If that makes any sense to you).
I complained to Horizon Hobby & they sent me another stock prop that was easily balanced.
Many are using other brand props with success.
[B]Make sure the prop is balanced or you may loose your carbon Z Yak![/B]
Feb 26, 2011, 08:18 PM
Destructive Tester
jimmy34256's Avatar

Back ????


So the thread lives on after much weirdness.....

Anyway, awaiting someones aftermarket custom CNC motor mounts to get back into the air. Or, I will have to resort to my bandsaw and drill press......
Feb 26, 2011, 09:56 PM
smoke is my wattmeter
It's the other thread Carbon Z thread that's still missing. It had 940 watts! in the title.
Feb 26, 2011, 11:11 PM
certified crash instructor
I'm not sure if my propeller is balanced, checked it on the balancer and it looks fine but I have a slight vibration and it sounds like a lawn mower at full throttle. I'm not sure if this is normal or not, never had a plane this big with this kind of power but I think I will get a new prop and see if there is a difference.
Feb 27, 2011, 01:49 AM
sotog's Avatar

E-Flite CZ Yak 54 CNC Machined Aluminum Motor Mount


I ran a batch of new CNC machined aluminum motor mounts for the E-Flite CZ Yak 54 today. This is a replacement for the stock mount which will use the original mounting screws to secure the motor and mount.

The overall length and width of the mount is identical to the stock one as well as the mounting holes and radius on the ends of the spokes. Spoke width is the same as stock towards the end of the spokes.

I did slightly increase the center section and beginning of the spokes (where the motor bolts onto) for a bit more strength.

I added motor mounting slots to accommodate motors with bolt patterns of 19x19mm, 19x25mm, and 25x25mm. The stock motor has a 25x25mm pattern so it will still bolt on perfectly.

Thickness of the mount is identical to stock at .125" thick.

Weight = 7.9g (stock mount is 7.8g)

If anyone is interested, please send me a PM.

Thanks,

Terry
Feb 27, 2011, 02:09 AM
sotog's Avatar
Quote:
Originally Posted by jimmy34256
Or, I will have to resort to my bandsaw and drill press......
No need for that! Though it is always fun to make your own parts!

Terry
Feb 27, 2011, 05:31 AM
Whoooo!
StormJunkie's Avatar
My motor seems to have a "hard" spot in it when turned by hand. Even made a sort of clicking sound sporadically when turning by hand. Will try and figure out more about what's causing this.
Feb 27, 2011, 10:08 AM
3D and slope Pilot in training
Gotlieb's Avatar
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Feb 27, 2011, 04:55 PM
Team Hillbilly
tominator06's Avatar
Ok so I had a little crash with the yak 54 and stripped the gear on one of the aileron servos. I have a brand new hs65hb sitting here and was wondering which tail servo I should switch it out with. It has more torque than the eflite servos but I'm not sure about speed. What does everyone think? I was thinking elevator.
Feb 27, 2011, 06:52 PM
Whoooo!
StormJunkie's Avatar

Crack-a-Yak-a-Lak...


For the second time in two days, I split my Yak in the usual spot. Yesterday it was the 2' high water main in the pic below that got me on a landing. Today it was a hard landing (three point I think) that snapped it mostly a 1/4" away from yesterday's crack. So this time I'm going to add a little CFRP to the repair job.

There will be a short .25" dia CF tube run along the middle spar in the fuse (see pic). This should add support in all direction from pretty much the middle of the airframe. The longer spar will be run along the bottom as pictured from the landing gear/hatch door plate all the way back to where the tail becomes one piece (just past the seam line back there). The spar is a .0125" x.125" and is going to be epoxied in after the fuse is epoxied back together. This is a very thin spar, but since it is oriented vertically, it should provide a fair amount of protection from the problems I've had with the breaking fuse. It will also provide some additional horizontal support as well since it will be tightly epoxied in between the foam. I may cut a couple more of those same size spars into the side of the fuse; but might run it with these spars and see how it holds up before adding more CFRP and epoxy and weight to the tail.

On a better note, the motor seemed to run well today and I have not seen any wear on the motor mount yet (it's only got five flights on it since I replaced it due to visual stress fractures).
Last edited by StormJunkie; Feb 27, 2011 at 07:24 PM.
Feb 27, 2011, 07:00 PM
Team Hillbilly
tominator06's Avatar
I see that the hs65 is too small to use. I'll have to get a new servo or a gearset.
Feb 27, 2011, 07:05 PM
Whoooo!
StormJunkie's Avatar

Servo size...


Quote:
Originally Posted by tominator06
I see that the hs65 is too small to use. I'll have to get a new servo or a gearset.
What size are the servos on the Yak? Is there a Hitec or other after market servo that fits the pre-mounted frames?
Feb 27, 2011, 08:03 PM
certified crash instructor
Quote:
Originally Posted by sotog
No need for that! Though it is always fun to make your own parts!

Terry
I like to make my own parts from time to time but you can't beat the cnc, so I just ordered one of sotog mounts, puts an end to my worries! Thanks again Terry, looking forward to installing this!
Feb 27, 2011, 08:58 PM
Whoooo!
StormJunkie's Avatar

She'll be back in the air in no time...


Opted for Gorilla Glue to put the spar in. Gives me plenty of working time and should really fill the gaps underneath as I worked it in pretty good. The spar runs from plastic tail plate to rx hatch. Will fill in any remaining gaps with 5min epoxy.

Will do this from the start whenever I switch to the new air frame sitting in the hanger.


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