Model Boat Mayhem

The Shipyard ( Dry Dock ): Builds & Questions => Yachts and Sail R&D: => Topic started by: FrankM on November 03, 2009, 09:46:48 pm

Title: HS-815BB Problem
Post by: FrankM on November 03, 2009, 09:46:48 pm
Hi all,

I sail model yachts and mostly use the 815BB servo from Hitec for sail control. No problems for years until recently when one of them appeared to be slipping the gears under load.

Upon inspection, ie dismantled, it appears the rear end shaft (the small one at the opposite end to the big main cog) which supports two cogs had slipped down about 1 - 2mm and was not engaging with its corresponding mounting hole in the top case. This allowed a degree of lateral movement which would explain the problem. The shaft I believe should be a tight fit in its base mounting but perhaps the loads its been under have allowed it to loosen.

I may be able to make a small shim to go under the shaft and hold it up but It won't be easy and I'm not sure it would either work or last long.

Has anyone else experienced a similar problem with this model servo and if so, how did the problem get resolved.

I'd really like to fix this as new servos are not cheap.

The servo is in the model shown in my Avatar.

Title: Re: HS-815BB Problem
Post by: FrankM on November 04, 2009, 10:18:50 am
C'mon you guys - don't tell me I've stumped you all. 

Someone out there must have a bright (not smarta*se) idea....................PLEASE

Title: Re: HS-815BB Problem
Post by: tigertiger on November 04, 2009, 10:47:10 am
I can only think that you got a rogue duff servo.

Has the cog by anychance just slipped down its shaft a bit. Is it moveable, that is does yours move?
Title: Re: HS-815BB Problem
Post by: tony23 on November 04, 2009, 08:35:08 pm
can you get a dab of torque seal on a tooth pick and get it onto the shaft then slide the cog back where it should be failing that cyno with this applicator should do it but be careful.

Title: Re: HS-815BB Problem
Post by: FrankM on November 04, 2009, 08:57:53 pm
Thanks Guys,

I've had that servo in the boat for close to 3 years and sailed in some pretty windy conditions.  It controls both mainsails and the main jib so there has been a lot of strain. So I'm guessing fair wear and tear but unexpexted.  Its not the cog but the shaft position that is the problem.

I'll give your idea a try.  Currently, I've managed to push the shaft up a tad and its working fine.  I just need to keep the shaft from slipping down again.

Thanks again,
Title: Re: HS-815BB Problem
Post by: bigH on November 05, 2009, 04:57:48 pm
Hi Frank,  the best thing you can do Frank is to dump the servo,...... I know, you don't want to do that
but believe me it is for the best.   You will never be able to have full confidence in the unit even if you
do (FIX) it, it may, (Sod's Law)give up the ghost in a position when you really might need to control
your boat.   Not nice to see your much loved boat go screaming off to that great lake of the edge of
the world.
Buy the best unit that you can afford and one that is strongly reccomended by other yachtsmen, you
 should then have many happy years of sailing.    As chairman of the 'South Wales (UK) Model Yacht Club'
My members would replace every time.   All the best mate  bigH
Title: Re: HS-815BB Problem
Post by: tigertiger on November 06, 2009, 01:27:48 am
Yes buy a new one, if you have been happy with the HS815BB get another.

I like them and the HS815BB is one of the cheapest, as well as one of the most powerfull. :-))