[Lazy Ace]

Originally Posted by wollins

Dennis this is an adapter I need for an electric motor. The one I have depicted in the pics (pic #2 and #3) at 26.5mm long is just a little short for the prop I want to use.

Either a "collet" type adapter (pic #1) or a "back mount" type adapter (pic #2 and #3) would work but I prefer the latter type cause I've found on the odd occasion that the collet type can be out of true since it cinches down on the motor shaft itself. (which can be slightly out of true itself)

On the other hand the backmount type bolts directly onto the motor itself therefore this type tends to run true more consistently.

Colin

You are absolutely right those collet style and even the set screw type are definitely not as good as the bolt on you have pictured. The clamp on or collet style tend to deform with overtightening. Then they can run out of true causing all kinds of vibration.

You have two problems one finding one long enough to suit your needs and the second the adaptor must fit the motor bolt holes and center boss correctly or you risk runout.

Why exactly do you need the extra length? Is it to accommodate the prop/spinner hardware? If it is, could it be because you’re attempting to run standard IC style prop and spinner? Electric specific props and spinners tend to be thinner at the hub so they fit most of these adaptors. The props and spinners being much lighter also cause less vibration and in my opinion work more efficiently with the electric combination.

I have only made two adaptors and they are really fussy to get perfect. Both times they took two trys to get them to my satisfaction. What I have done is to make a recessed nut that has a bit of an oversized shank that fits part way down inside the prop to give enough thread contact to secure the nut. True Turn as has quite a few options and they advertise the adapters as being longer than the stock or regular ones. http://www.truturn.com/product_line.html

Dennis

[Thunder Chicken]

Not sure if this guy would have what you need, but I liked the few I got for m SK3 series motors. His store on eBay is Smallpartscnc

http://www.ebay.ca/usr/smallpartscnc...19.m1438.l2754

[hitechflyer]

This would work fine and no concerns of compromising the strength of the prop.

[davidmc36]

Originally Posted by wollins

These are for electric motors? Ok I found what I assume you're talking about at http://www.osengines.com/motors/moto...dimensions.pdf These would be perfect only the longest one for a 5mm motor shaft is only 25mm. The next one up (for a 6mm motor shaft would have been perfect at 34mm!

That looks like the ones. You really do need a long one. Those OS solved all my issues.

[michaely]

Colin,

Can you more completely identify the motor you are trying to use?
Details such as mounting bolt pattern, shaft size, etc. would be useful to know.

One "way out" idea: Hacker, in their A30, A40, 50 series of outrunners, made a glider variant with an enlongated stainless steel/ball-bearing supported drive shaft to use in small diameter fuselage front ends.

https://hackermotorusa.com/shop/airc...-12-xl-glider/

I have the A30/12/xl size: the distance between the prop drive face and the face of the motor is a whopping 58 mm. The shaft diameter for this size is 5mm which is the same as your motor. Very rugged.

Hacker also made a "glider conversion kit", comprising of the longer shaft and surrounding ball-bearing "carrier", with necessary bolts. in each motor size.

good luck,

[stegl]

Originally Posted by Lazy Ace

.


I have only made two adaptors and they are really fussy to get perfect. Both times they took two trys to get them to my satisfaction. What I have done is to make a recessed nut that has a bit of an oversized shank that fits part way down inside the prop to give enough thread contact to secure the nut. True Turn as has quite a few options and they advertise the adapters as being longer than the stock or regular ones. http://www.truturn.com/product_line.html

Dennis

Doesn't seem to be too interested in Tru Turn.... have checked their website and see that they are now making bolt on shafts in 3 and 4 bolt setups. too bad they don't give shaft length or useable shat length taking into account the nut and washer.

[Lazy Ace]

I have never had a problem with the stock adaptors using electric props. I have had tight fits using standard props but I still used the electric spinners which have a thinner back plate.

Dennis

[wollins]

Originally Posted by michaely

Colin,

Can you more completely identify the motor you are trying to use?
Details such as mounting bolt pattern, shaft size, etc. would be useful to know.

It's the NTM Prop Drive 35-48 Series 900KV.
http://www.hobbyking.com/hobbyking/s...FQ8vaQodHv8COQ

[Lazy Ace]

Ouch makes it hard when there is no measurement data on the end of the motor. The only way I could see would be to measure it up and try and cross reference it.

Dennis

[wollins]

Ok I'll get some of those numbers for you