 |
Matronics Email Lists
Web Forum Interface to the Matronics Email Lists
|
| View previous topic :: View next topic |
| Author |
Message |
sabean
Joined: 13 Dec 2010
Posts: 1
|
 Posted: Fri Aug 26, 2011 4:48 am Post subject: 912ULS Shudder on Shutdown |
 |
|
On occasion when the engine shuts down, there is a noticeable shudder. Some times it is quite violent. Almost as if the prop stops immediately when the key is turned off. Idle RPM is set at 1800. I turn off 1 mag prior to shut down to achieve approximately 1650RPM.
Any comments/suggestions??
Thanks,
Tom S
| | - The Matronics RotaxEngines-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RotaxEngines-List |
|
|
|
| Back to top |
|
 |
Roger Lee
Joined: 10 Jan 2006
Posts: 1464
Location: Tucson, Az.
|
| Posted: Fri Aug 26, 2011 6:06 am Post subject: Re: 912ULS Shudder on Shutdown |
|
|
Hi Tom,
It would be good to know what the friction torque is for the gearbox if it is a 912ULS? Making sure the carbs are synced at idle.
Then sometimes it is normal due to a couple of things you have no control over and like you siad is intermittent.
| | - The Matronics RotaxEngines-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RotaxEngines-List |
|
_________________
Roger Lee
Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056 |
|
| Back to top |
|
|
Rich L
Joined: 23 Feb 2008
Posts: 63
Location: North Idaho
|
| Posted: Sat Aug 27, 2011 4:22 am Post subject: Re: 912ULS Shudder on Shutdown |
|
|
I have the same engine and the same problem. I tried all the tricks I saw on these blogs for 4 years and it sometimes worked but not always. For about the last 20 flights I have put the throttle to about 2200 just before shutdown. Then pulled the throttle and turned off the ignition at the same time. Smooth as glass and not a shudder since.
| | - The Matronics RotaxEngines-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RotaxEngines-List |
|
_________________
Rich Little
N812RL S-7 912ULS
North Idaho
Kiev Prop |
|
| Back to top |
|
|
Goodone
Joined: 13 Sep 2008
Posts: 49
|
| Posted: Sun Aug 28, 2011 6:26 am Post subject: Re: 912ULS Shudder on Shutdown |
|
|
I do the same as Rich and have the same result with my 912 UL.
| | - The Matronics RotaxEngines-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RotaxEngines-List |
|
|
|
| Back to top |
|
|
Roger Lee
Joined: 10 Jan 2006
Posts: 1464
Location: Tucson, Az.
|
| Posted: Sun Aug 28, 2011 7:56 am Post subject: Re: 912ULS Shudder on Shutdown |
|
|
It would be interesting if you guys would tell us what the friction torque is on the gearbox and if you use a Warp Drive, it's length and if it has nickel edges.
I like Warp Drive and I have been using them for years. I just removed my 66" Warp drive no nickel edge and put on a lighter composite 68" Sensenich prop. The shakier starts and stops went away and it is quieter in the cockpit. I'm still running some test so I'll get back with more later.
| | - The Matronics RotaxEngines-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RotaxEngines-List |
|
_________________
Roger Lee
Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056 |
|
| Back to top |
|
|
Thom Riddle
Joined: 10 Jan 2006
Posts: 1597
Location: Buffalo, NY, USA (9G0)
|
| Posted: Sun Aug 28, 2011 8:08 am Post subject: Re: 912ULS Shudder on Shutdown |
|
|
Roger,
The lower MOI of lighter props makes a big difference. As long as you get the right dia. and pitch, a light fixed pitch wood or composite prop is my first choice.
| | - The Matronics RotaxEngines-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RotaxEngines-List |
|
_________________
Thom Riddle
Buffalo, NY (9G0)
Don't worry about old age... it doesn't last very long.
- Anonymous |
|
| Back to top |
|
|
Dick Maddux
Joined: 24 Jun 2008
Posts: 516
Location: Milton, Fl
|
| Posted: Mon Aug 29, 2011 4:35 am Post subject: 912ULS Shudder on Shutdown |
|
|
Roger,
I did the same thing. I replaced my Warp taper tip ,nickel edge with a lighter Kiev. In addition to a turbine smooth engine in cruise, the shutdown is flawless which it sure wasn't before ! AND at very low rpm there is no longer any gearbox noise. The Warp now makes a good wall mount decoration for my hanger. Anyone want to buy it ? It has the hub for the early mid 90's 912UL.
Dick Maddux
Milton,Fl
[quote][b]
| | - The Matronics RotaxEngines-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RotaxEngines-List |
|
|
|
| Back to top |
|
|
lucien
Joined: 03 Jun 2007
Posts: 721
Location: santa fe, NM
|
| Posted: Mon Aug 29, 2011 6:51 am Post subject: Re: 912ULS Shudder on Shutdown |
|
|
Though I never had that problem with my warp drive (68" 3 blade), I now have a powerfin F model (70" 3-blade) on my tornado/912ULS and it's smooth as silk at idle and shutdown.
I did talk to Daryl at WD back when I was trying to debug my vibration problem with my WD and he assured me it was within the MOI limits of the 912 gearboxes. And like I said, I never had any kind of problems with mine at idle or on shutdown.
The 3 blade IVO medium that was on the plane when I bought it, tho, was a different story. The idle was significantly rougher and the engine seemed to spin for an eternity after killing the mags. But that thing weighs almost a full 10lbs more than my Powerfin!
I checked my friction torque a while back and it was about 450in/lbs, somewhere in there. About the middle of the range Rotax specifies anyway. And there was no problem with the Warp Drive on mine.
So perhaps it is a low friction torque on the box?
LS
| | - The Matronics RotaxEngines-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RotaxEngines-List |
|
_________________
LS
Titan II SS |
|
| Back to top |
|
|
stolspeed(at)gmail.com
Guest
|
| Posted: Mon Aug 29, 2011 5:50 pm Post subject: 912ULS Shudder on Shutdown |
|
|
I've tested many brands of prop, and rotational inertia makes a big difference to start/stop sudder. The Warp Drive was the heaviest and the roughest by far, and difficult to balance for really smooth running.
See results of the comparison testing at
http://www.stolspeed.com/id/62
JG
[quote][b]
| | - The Matronics RotaxEngines-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RotaxEngines-List |
|
|
|
| Back to top |
|
|
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum
|
Powered by phpBB © 2001, 2005 phpBB Group
|
Get Email Distribution Too!
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
