---------------------------------------------------------- RV10-List Digest Archive --- Total Messages Posted Mon 04/15/19: 4 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:45 AM - Re: Elevator Pitch Servo Failure (Bill Watson) 2. 06:52 AM - Re: Re: Elevator Pitch Servo Failure (Bill Watson) 3. 04:16 PM - Re: Elevator Pitch Servo Failure (Eagerlee6) 4. 04:48 PM - Re: Re: Elevator Pitch Servo Failure (Jesse Saint) ________________________________ Message 1 _____________________________________ Time: 06:45:49 AM PST US Subject: Re: RV10-List: Elevator Pitch Servo Failure From: Bill Watson Thanks for sharing. I'm at 1100 hours and the trim servo has done more flying than I... Bill "in the middle of a series of minor 1,000 hour failures" Watson On 4/14/2019 1:59 PM, Jim Combs wrote: > Had an elevator pitch servo fail on a flight yesterday. The cable > pulled out of a hole that uses a set screw to hold the cable in place. > It's a TruTrak pitch servo. It uses a cable that wraps around a drum. > Each end of the cable is attached to an aluminum channel. > > 1200 hours on the airplane with no prior issues. The pilot said the > elevator felt funny on any up travel past neutral. He also heard a > clicking noise as it passed the neutral point. > > An engineering EC would be to leave the cable slightly long and crimp > a sleeve onto the cable as a a failsafe for the set screw(s). > > I will call TruTrak tomorrow to see if this should be replaced or > repaired. I will be adding this to my inspection checklist. I > noticed nothing during the last condition inspection. > > Not sure exactly when it failed. It was noticed prior to a return > flight from another airport. Removal of the bulkhead and removing the > control arm of the servo from the elevator bellcrank was done to allow > the flight home. > > N312F - 1200 hours > > Jim Combs --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ________________________________ Message 2 _____________________________________ Time: 06:52:39 AM PST US Subject: Re: RV10-List: Re: Elevator Pitch Servo Failure From: Bill Watson Seems like an elegant, easy to implement fail safe mod. I take it that there may not be an easily identifiable failure mode where the elevator does jam, but the fact that a stiff control arm could be flopping about is enough to justify a fail safe mod. Thanks for sharing! On 4/14/2019 7:12 PM, bill.peyton wrote: > > Hi Jim, > I was always concerned with this design of the pitch servo. I spoke with TT about it 8 years ago and they assured me they had redesigned the force multiplier to remedy this issue. Yours is not the first time this has happened. Just consider yourself extremely fortunate that the arm did not jam the entire elevator operation. > I designed a fail-safe retainer to prevent this from happening should the cable come loose. I also shared this with TT. Here are a few photos of my modification. > > -------- > Bill > WA0SYV > Aviation Partners, LLC > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=488739#488739 > > > Attachments: > > http://forums.matronics.com//files/img_1940_270.jpg > http://forums.matronics.com//files/img_1939_314.jpg > http://forums.matronics.com//files/img_1937_412.jpg > http://forums.matronics.com//files/img_1936_183.jpg > http://forums.matronics.com//files/img_1935_180.jpg > http://forums.matronics.com//files/img_1933_207.jpg > http://forums.matronics.com//files/img_1934_160.jpg > > --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ________________________________ Message 3 _____________________________________ Time: 04:16:14 PM PST US From: Eagerlee6 Subject: RV10-List: Re: Elevator Pitch Servo Failure I have a two axis TruTrak DigiTrak autopilot with an AlTrak altitude hold and did NOT install the torque multiplier. When the elevator trim is set for light stick pressure the pitch servo has no problem(in 140 hours) keeping the altitude correct. Does anyone else use the stock servo without the enhancer? PH On Apr 15, 2019, at 12:44 AM, RV10-List Digest Server wrote: ______________________________Message 2 _____________________________________ Time: 11:33:03 AM PST US From: Jim Combs Subject: RV10-List: Elevator Pitch Servo Failure Had an elevator pitch servo fail on a flight yesterday. The cable pulled out of a hole that uses a set screw to hold the cable in place. It's a TruTrak pitch servo. It uses a cable that wraps around a drum. Each end of the cable is attached to an aluminum channel. 1200 hours on the airplane with no prior issues. The pilot said the elevator felt funny on any up travel past neutral. He also heard a clicking noise as it passed the neutral point. An engineering EC would be to leave the cable slightly long and crimp a sleeve onto the cable as a a failsafe for the set screw(s). I will call TruTrak tomorrow to see if this should be replaced or repaired. I will be adding this to my inspection checklist. I noticed nothing during the last condition inspection. Not sure exactly when it failed. It was noticed prior to a return flight from another airport. Removal of the bulkhead and removing the control arm of the servo from the elevator bellcrank was done to allow the flight home. N312F - 1200 hours Jim Combs ________________________________ Message 4 _____________________________________ Time: 04:48:17 PM PST US From: Jesse Saint Subject: Re: RV10-List: Re: Elevator Pitch Servo Failure We had the standard Servo in the beginning. It worked ok, but the torque enhancer was much better. Jesse Saint Saint Aviation, Inc. jesse@saintaviation.com C: 352-427-0285 F: 815-377-3694 Sent from my iPhone > On Apr 15, 2019, at 7:15 PM, Eagerlee6 wrote: > > > I have a two axis TruTrak DigiTrak autopilot with an AlTrak altitude hold and did NOT install the torque multiplier. When the elevator trim is set for light stick pressure the pitch servo has no problem(in 140 hours) keeping the altitude correct. Does anyone else use the stock servo without the enhancer? > > PH > > > On Apr 15, 2019, at 12:44 AM, RV10-List Digest Server wrote: > ______________________________Message 2 _____________________________________ > > > Time: 11:33:03 AM PST US > From: Jim Combs > Subject: RV10-List: Elevator Pitch Servo Failure > > Had an elevator pitch servo fail on a flight yesterday. The cable > pulled out of a hole that uses a set screw to hold the cable in place. > It's a TruTrak pitch servo. It uses a cable that wraps around a drum. > Each end of the cable is attached to an aluminum channel. > > 1200 hours on the airplane with no prior issues. The pilot said the > elevator felt funny on any up travel past neutral. He also heard a > clicking noise as it passed the neutral point. > > An engineering EC would be to leave the cable slightly long and crimp > a sleeve onto the cable as a a failsafe for the set screw(s). > > I will call TruTrak tomorrow to see if this should be replaced or > repaired. I will be adding this to my inspection checklist. I > noticed nothing during the last condition inspection. > > Not sure exactly when it failed. It was noticed prior to a return > flight from another airport. Removal of the bulkhead and removing the > control arm of the servo from the elevator bellcrank was done to allow > the flight home. > > N312F - 1200 hours > > Jim Combs > > > > ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message rv10-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/RV10-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/rv10-list Browse Digests http://www.matronics.com/digest/rv10-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.