I have had three 81mg's in two Manti in two years just up and stop on me in flight. All on the v-tail, talk about fun flying. Haven't sent them in, although I would like to know if anyone has and what the explanation of the failure is.
Bill >From: "tailheavy" <[EMAIL PROTECTED]> >To: "soaring Exchange" <[EMAIL PROTECTED]> >Subject: [RCSE] HS-81 failure , almost like clockwork ? >Date: Sun, 14 Apr 2002 20:05:20 -0600 > >Just over a year ago I outfitter my first fullhouse glider (arthobby >sierra) >with a brand new set of HS-81s on all 6 surfaces (vtail , flaps , ailerons >) >. > >Now I DO fly almost every day , so there is plenty of flight time on this >equipment , wild guestimate ~ 150-300 hours for this ship . (much more on >my >hlgs) . > >Last Monday the sierra felt weird then the elevator control went weak , but >still somewhat functional . Landed safely - np (good argument for vtail - >comes back with only one !) . Sure enough one of the ruddervators had >stopped working . Gearset worked smoothly , a couple twitches then dead >like >no connection . > >Failed 81 , pack it up and send it into Hitec , along with a flap servo >that >failed a month ago ( my bad I thought , flap-down landing may have stressed >it ) . > >Of course , one day after shipping out the servos the second vtail servo >failed . >Odd I thought , these vtail servos failed within an hour or so of each >other >after a non-trivial (but short IMHO) amount of service life . >Since the vtail servos are pretty much working in tandem , I guess each has >seen nearly the same movement over time . >It just seems too coincidental . > >Could a year (or a couple hundred hours) be the service life of the pots or >some other components ? The shafts have also become worn and pretty sloppy >. > >I've been hooked on flying for close to 15 years ( strictly power until a >couple years ago , when I graduated to sailplanes ! ) . In that time I've >flown as much as possible , I've only had a couple servos fail ( not >counting gearsets / wiring / obvious crash damage ) . Something I never >gave >much thought to was exceeding the MTBF(mean time before failure) of my >servos . > >Anyone have this kind of data available ? > >I'm a little nervous about the remaining 81's if this is the problem , soon >the ailerons may fail as well . >When I replaced the flap servo I did both with 85MGs - seem much better . >Definitely stronger mechanically , but is there any reason to believe the >85s are more robust internally(pots/chips) and will last longer ? > >I was going to use the surviving mate to the flap that failed (81) on a >"hover at half throttle" sukhoi as a throttle control . But if it is about >to fail itself - no way ! Not a plane you want to fly stuck wide open - >horribly overpowered to hover without working hard . (~5lb even with 91 >saito) No biggie buying another new servo if I need to (all the rest are >new) , now I think maybe I should . > >Don't want to buy more 81s if a little more cash will last a whole bunch >longer . > >Should I be sending 81's in routinely for factory inspection ? >(Are these servos more prone to vibration failure for powerplanes ?) >Has anyone else noticed wearout failure with the 81s or 85s ? >How about experience with 225's ? > >I gotta say - Hitec has always done good by me ! >Their service dept is excellent and they do stand behind their products ! >Just wondering if I need to upgrade everything ? >Maybe this was just a coincidence or a poor lot of servos . > >Thanks in advance , > Wayne > > > >RCSE-List facilities provided by Model Airplane News. Send "subscribe" and >"unsubscribe" requests to [EMAIL PROTECTED] > _________________________________________________________________ Chat with friends online, try MSN Messenger: http://messenger.msn.com RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
