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abanihani · 12-04-2011, 02:35 PM

I have a stretched mini protos, FBL, min vbar on 6s battery and 1300KV motor. I took out today and the first 2 flights were awsome, on the 3rd one I suddenly lost head speed while inverted and was able to turn it back upright and land safely without damage. Upon inspection I noticed the belt has slipped upward towards the 3rd bearing and outside the belt bulley. Is this a sign of loose belt tension to start with or is it my 14 tooth pinion? In the past I was able to split the pinion in half but not this time, the pinion seems fine. I have been having bad luck with my mini protos and never able to complete 4-5 flights without an incident related to either the pinion or belt slippage. I have 2 500 size protos stretch that never experienced with them any failures in over than 100 flights. Something I am not getting right with the mini. I appreciate any advise.

abanihani · 12-04-2011, 05:08 PM

I think I found the culprit, I found the front belt bulley eaten up! I replaced it with an aluminum upgrade I already have, will see how that works.

desertstalker · 12-04-2011, 05:28 PM

Quote:

Originally Posted by abanihani

I think I found the culprit, I found the front belt bulley eaten up! I replaced it with an aluminum upgrade I already have, will see how that works.

Yeah, I was wondering how you could get the belt to slip up with all the pulleys in place, did you check all the others as well?

I have the belt on mine pretty loose (would be far too loose on any of my other helis) and the belt cannot be pushed up over any gear by hand, so its not slipping up or down in flight.

abanihani · 12-04-2011, 06:03 PM

I guess that was the reason, all the others are okay, I may had the front one under alot of tension and with the heat it just got melted slowly until it gave away, luckily no damage, I upgraded all four bulleys into aluminum now.

ziper_it · 12-05-2011, 12:12 AM

I had the same issue with that pulley. Now I mounted the alu one.

Picofly · 12-05-2011, 12:47 AM

Quote:

Originally Posted by abanihani

I guess that was the reason, all the others are okay, I may had the front one under alot of tension and with the heat it just got melted slowly until it gave away, luckily no damage, I upgraded all four bulleys into aluminum now.

Did you find the reason why the pulley has melted away? It doesn't melt just like that. There must be a lot of extra friction (the pulley binds to the frame or the bearing is damaged).

I had a similar issue in my Protos 500. One of the pulleys melted away. When I studied it closer I noticed that it hardly turned at all because it was binding to the tail box.

ziper_it · 12-05-2011, 02:10 AM

Yep, pulley in the tail should not tighten too much. I was able to consume it til the bearing was visible!

The one on the front is kept by a pin, but the holes to screw it to the frame allow for some play. After mounting the new one make sure the belt is well seated by spooling up then see if the pulley position needs to be adjusted.

12-04-2011, 02:35 PM	#1 (permalink)
abanihani Registered Users Join Date: Dec 2009	belt slippage I have a stretched mini protos, FBL, min vbar on 6s battery and 1300KV motor. I took out today and the first 2 flights were awsome, on the 3rd one I suddenly lost head speed while inverted and was able to turn it back upright and land safely without damage. Upon inspection I noticed the belt has slipped upward towards the 3rd bearing and outside the belt bulley. Is this a sign of loose belt tension to start with or is it my 14 tooth pinion? In the past I was able to split the pinion in half but not this time, the pinion seems fine. I have been having bad luck with my mini protos and never able to complete 4-5 flights without an incident related to either the pinion or belt slippage. I have 2 500 size protos stretch that never experienced with them any failures in over than 100 flights. Something I am not getting right with the mini. I appreciate any advise.

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12-04-2011, 05:08 PM	#2 (permalink)
abanihani Registered Users Thread Starter Join Date: Dec 2009	I think I found the culprit, I found the front belt bulley eaten up! I replaced it with an aluminum upgrade I already have, will see how that works.

12-04-2011, 06:03 PM	#4 (permalink)
abanihani Registered Users Thread Starter Join Date: Dec 2009	I guess that was the reason, all the others are okay, I may had the front one under alot of tension and with the heat it just got melted slowly until it gave away, luckily no damage, I upgraded all four bulleys into aluminum now.

12-05-2011, 12:12 AM	#5 (permalink)
ziper_it Registered Users Join Date: Mar 2010	I had the same issue with that pulley. Now I mounted the alu one.

12-05-2011, 02:10 AM	#7 (permalink)
ziper_it Registered Users Join Date: Mar 2010	Yep, pulley in the tail should not tighten too much. I was able to consume it til the bearing was visible! The one on the front is kept by a pin, but the holes to screw it to the frame allow for some play. After mounting the new one make sure the belt is well seated by spooling up then see if the pulley position needs to be adjusted.

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