Third bearing pinion support

[dl5973]

Hi Guys,

does anyone know what size bearing fits in the 3rd bearing pinion support for a stretched P500?

I had an accident a few weeks ago that stuffed this nearing up.

I did not realise this bearing was missing when I flew it today and I snapped my long motor shaft mid flight.

[flint723]

It's 4x9x4.

I'm surprised it snapped the shaft, I flew a stretch with no 3rd bearing for 50 flights or so before it ruined my top motor bearing.

[DoubleCH]

It's possible that whatever caused you lose the 3rd bearing might have caused damage or bent the long motor shaft. The long shaft material is not that strong. My 14T top OWB wore a grove into my long shaft and made both OWBs slipped occasionally and I had to throw the shaft away. I'm now running a custom shaft adaptor on the short shaft to prepare that I can easily and cheaply replace insert for the OWBs to wear out. So far so good [knock on wood] after many times more number of flights over and no sign of slippage yet.

[dl5973]

I actually meant the bearing that sits in the y support bracket that the long shaft sits in for the stretched protos

sorry if I did not make myself clear

I found out bearing is 4x8x2 but MSH does not sell it.

Yes the long motor shaft snapped right at the base where it goes form 5mm to 4mm diameter. I never thought this could happen.

I am convinced the long motor shaft is weak.

Had me perplexed.

[flint723]

Unless there are different versions it is 4x9x4, says right on the bag and verified with caliper.

[dr dremel]

Originally Posted by DoubleCH

I'm now running a custom shaft adaptor on the short shaft to prepare that I can easily and cheaply replace insert for the OWBs to wear out. So far so good [knock on wood] after many times more number of flights over and no sign of slippage yet.

I also noticed some wear on the long shaft. What does your custom adapter look like? I´ve used cut off drill bits before as motor shafts. Something along this line?

Dr

[DoubleCH]

No, my design's top priority is to have a 4mm insert easily and cheaply replaceable considering how quick the long shaft wore out. I put back the short shaft, cut down the worn 4mm shaft adapter at the base then drill a 4mm hole perfectly center for the 4mm insert. I then tapped 2 3mm set screw holes opposite sides on the shaft adaptor to make sure I can fine tune 4mm insert to be as prefectly center as possible. I cut a 5/32" piano wire into length and file flats for the set screws. The piano wire is surprisingly hard. I use the same piano wire to make custom short mainshaft for my Blade 300x and I couldn't make jesus bolt hole after ruining a few good drill bits using my drill press. I could't even drill more than 1mm deep. In the end I changed my jesus bolt design for the 300x mainshaft to flat-n-set-screw and key-n-key-slot designs which work really well. And I've crashed my custom shaft a couple times no bend. Anyways the 13T OWBs aren't slipping yet [knock on wood] although I can make refill inserts in like 3 mins each. A brand new long shaft would've worn out way earlier.

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[DoubleCH]

Originally Posted by flint723

Unless there are different versions it is 4x9x4, says right on the bag and verified with caliper.

I can confirm the 3rd bearing is indeed 4x9x4. I've worn out a few of them. Luckily I found some 4x9x4 bearings for some obsolete heli (I think Hirobo) at my LHS so I grabbed all of them. I found an alternative source for 4x9x4 in case I run out of my stock.

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[dr dremel]

Thanks for the explanation, DoubleCH. I have an old adapter lying around, maybe I can come up with something similar.

[crickr1]

Originally Posted by dl5973

I actually meant the bearing that sits in the y support bracket that the long shaft sits in for the stretched protos

sorry if I did not make myself clear

I found out bearing is 4x8x2 but MSH does not sell it.

Yes the long motor shaft snapped right at the base where it goes form 5mm to 4mm diameter. I never thought this could happen.

I am convinced the long motor shaft is weak.

Had me perplexed.

It is 4x9x4 as others stated, I replaced with Bocca Bearings and held up well. Still flying after almost 2 seasons.

[dl5973]

I got a bag saying Part no MSH51326

no2 BB 4x8x2.

so two bearings 4x8x2

[dl5973]

the mini P uses 4x9x4 bearings so spare bearings is not a problem

I cant find 4x8x2 bearings

[DoubleCH]

4x8x2 are the ones inside pinion. 4x9x4 is the one inside V-bracket. Which bearing on mini is 4x9x4?

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[dl5973]

http://www.helidirect.com/msh41072-m...os-p-22791.hdx

[DoubleCH]

Excellent. Can't find it on msh-direct or heliproshop so that's why I've never come across this. Well it's out of stock anyways, but thanks anyways.

[dl5973]

http://www.amain.com/product_info.ph...-Bearing-Set-2

Its available here

[DoubleCH]

Yeah saw that one earlier today. Thanks.

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