Running KDE Mount+700M Shaft-Read This

[Mystic3D]

I have been running the KDE adjustable motor mount with the Align 700M while waiting for my long shaft for Scorpion 5035-500. About 20 Flights on this setup.

Upon removing the motor I noticed the tip of the shaft about 2mm was ground down to a smaller O.D. I know the shaft did not come this way.

Since the KDE Mount is thicker that stock where the motor bolts on, it causes the shaft to not fully go down into the bottom bearing block.


This obviously is not good as the shaft should extend all the way through the bottom bearing block.
The 700M Shaft is 100mm Long
The Scorpion 4035 Long Shaft is 105mm Long
The pictures show the length from the mount to the end of shaft only

Solution: get the Scorpion 4035 Long Shaft, even if you run the 700M.
The shaft will then extend through the bottom of the bearing = GOOD :thumbup:

Benefit: Better Alignment of bottom bearing block. no excessive shaft wear which later would lead to vibration with play between shaft and bearing.

http://helifreak.com/attachment.php?attachmentid=169681&stc=1&d=1279858987

700M Shaft
http://helifreak.com/attachment.php?attachmentid=169682&stc=1&d=1279858987

4035 Long Shaft
http://helifreak.com/attachment.php?attachmentid=169683&stc=1&d=1279858987

[rceccleston]

Good advice, thanks. :thumbup:

However, the marking of the end of the shaft is caused by the motor shaft spinning within the inner racer of the upper bearing support.

A drop of bearing retaining compound on the end of the shaft would resolve this, by bonding the the inner racer to the end of the motor shaft.

[Mystic3D]

Good advice, thanks. :thumbup:

However, the marking of the end of the shaft is caused by the motor shaft spinning within the inner racer of the upper bearing support.

Great Observation. I believe the root cause of the shaft spinning in the bearing is if only a couple of mm of shaft is in the bearing.
a. It is not straight, aligned in the bearing, as not fully engaged
b. Shaft not fully through the bearing, less surface area to keep it from spinning.

Note: After I put the long shaft motor in I set the pinion mesh with the bottom bracket removed. Then put the bottom pinion support in. I hope this ensures it is straight....

[rceccleston]

Great Observation. I believe the root cause of the shaft spinning in the bearing is if only a couple of mm of shaft is in the bearing.
a. It is not straight, aligned in the bearing, as not fully engaged
b. Shaft not fully through the bearing, less surface area to keep it from spinning.

Note: After I put the long shaft motor in I set the pinion mesh with the bottom bracket removed. Then put the bottom pinion support in. I hope this ensures it is straight....
I have experienced the same issue with the third bearing block on my 12s T-Rex 600 and on various motors.

I agree, a longer shaft with a drop of bearing retaining compound would resolve the issue.

[Mystic3D]

I cannot believe I am the only one so anal about this....:arggg:

[fnity3632]

Dunno.... When I pulled the 700M it wasn't like that:dontknow
Under certain circumstances it can spin, but there is a way to fix it like rceccleston said a drop of loctite, I remember a while back hearing Finless talk about shoe goo to prevent this type of thing

[ping]

Shoe goo is for plastic parts. Retaining compounds like r-48 or green loctite are for metal parts.