---------------------------------------------------------- Europa-List Digest Archive --- Total Messages Posted Mon 04/25/05:8 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 12:05 AM - Re: bad cold starts (Pete Lawless) 2. 01:59 AM - Re: Re:Wastegate sticking on 914 (David Joyce) 3. 08:07 AM - Nav/Com & Transponder Antenna (EuropaXSA276@aol.com) 4. 12:17 PM - Re: bad cold starts (Duncan McFadyean) 5. 12:27 PM - Re: Re:Wastegate sticking on 914 (Duncan McFadyean) 6. 06:36 PM - Re: bad cold starts (SPurpura@aol.com) 7. 06:55 PM - Re: bad cold starts (Cliff Shaw) 8. 07:19 PM - Archive site has moved (Andrew Sarangan) ________________________________ Message 1 _____________________________________ Time: 12:05:15 AM PST US From: "Pete Lawless" Subject: RE: Europa-List: bad cold starts --> Europa-List message posted by: "Pete Lawless" David Yes that is exactly what it does. My engine started cold fine but would not come up to idle speed. Ran as if only 2 cylinders were firing, very rough with lots of vibration. It would take several attempts to get it to run smooth. Once it had fired up once then it was ok for the rest of the day. I believe it is the kick back that damages the sprag clutch but the bad starting, going into what the Rotax dealer in the UK describes as 'sub-idle' it the result. Regards Pete -----Original Message----- From: owner-europa-list-server@matronics.com [mailto:owner-europa-list-server@matronics.com] On Behalf Of David DeFord Subject: RE: Europa-List: bad cold starts --> Europa-List message posted by: "David DeFord" --> > If it sounds like it is running on 2 cylinders then it could > be sprag clutch. Have a look in the archive there is lots of > stuff about this. I have just changed my sprag clutch after > only 120 hours on a 912 ul. The problem was instantly cured. > > Pete Can a sprag clutch problem cause rough running after the starter is off (i.e., sprag clutch not disengaging)? I have been ignoring the sprag clutch/heavy-duty starter discussion, assuming that it referred only to kickback and other problems while the starter was actively driving the engine (problems which we haven't experienced). Thanks to all who have offered suggestions. We have carefully set the clutch cables so that both chokes hit their limit stops at the same time. We have also checked the temperatures of the exhaust pipes (both by feeling and by EGT reading) after a few seconds of rough running, and no significant difference was found between the port and starboard sides. Today we tried replacing the fuel in the float bowls with fresh auto gas. No help. After a few seconds of rough running, the port side carburetor sometimes overflows fuel into the air box, probably because the float needle gets shaken off of its seat. Cylinders 2 and 4 are then quickly flooded, which can be overcome only by opening the throttle far too much. We'll try starting with the fuel selector off, to see if we can avoid the flooding. Dave DeFord N135TD -- -- ________________________________ Message 2 _____________________________________ Time: 01:59:55 AM PST US From: "David Joyce" Subject: Re: Europa-List: Re:Wastegate sticking on 914 --> Europa-List message posted by: "David Joyce" John, Isn't this a case of designing in failsafe mode? Getting the boost set in max isn't the end of the world as long as you know about it, since throttling back should make everything manageable. If you had the wastegate failure mode giving zero boost then you could be in serious stuck if it failed on you when you were high up in inhospitable mountain country, or trying to climb out of somewhere hot, high and heavy. I appreciate that getting either a surge in power or a drop in power could be pretty distracting when you are in a circuit situation, but I think I might go for the surge personally! Regards, David Joyce G-XSDJ 914 XS ----- Original Message ----- From: "Graham Higgins" Subject: Europa-List: Re:Wastegate sticking on 914 > --> Europa-List message posted by: Graham Higgins > > After my prang which I believe was due to overboost from wastegate sticking, I > have been at a loss to understand Rotax thinking. The turbo charger wastegate > default position is closed - ie turbo operating fully unless otherwise > commanded by the electronic control system. If any part of that system fails, > there is risk of overboost, and major engine damage.They advocate warning > lights to show turbo surge, and if overboost is likely, simply recommend > "reduce power to acceptable limits, limit operations (land), and fix the > cause" > My question is why not have some more positive option for the pilot in this > situation than simply warning light(s). > Has anyone considered having a manual over-ride to open the wastegate when > the warning lights indicate overboost is likely? I would have had plenty of > power to fly clear of trouble on 80 hp. and avoided the severe damage to the > aircraft and myself,if I could have simply disabled the turbo, and used the > normally aspirated function of the engine. > It should not be too difficult a task to devise a cable attached to the > servomotor cable outer, so that the wastegate can be forced open if > necessary. I do not know what forces would be required, but it would need to > be greater than the servo motor to be of any benefit. > Has anyone else had similar thoughts, or done any research, or know the force > generated by the servo motor on the wastegate arm?? > I would like to have more options to do something about it when overboost is > threatening. > Graham Higgins in Oz. > 914, Mono, Airmaster, 98 hrs to prang, rebuilding, but wanting something > better before I fly again. > > Subject: Re: Europa-List: 914 Waste Gate Sticking > > > > --> Europa-List message posted by: "Fred Fillinger" > > > > > Upon departure, at about 1800' agl, the waste gate stuck > > > > > closed, the engine over boosted and snapped the crank. > > > > > John Lawton > > > ________________________________________________________________________ > Doctors.net.uk e-mail protects you from viruses and unsolicited messages > > Free education for all doctors. > The simple, fast way to prove you are keeping up to date. http://www.doctors.net.uk/education > _______________________________________________________________________ > > ________________________________ Message 3 _____________________________________ Time: 08:07:59 AM PST US From: EuropaXSA276@aol.com Subject: Europa-List: Nav/Com & Transponder Antenna --> Europa-List message posted by: EuropaXSA276@aol.com Hello Group I noted that many of you have installed the Bob Archer nav/com and transponder antenna in your aircraft. I wonder if any have chosen the Advance Aircraft Electronics units which are also available from Spruce. These units are a bit more expensive than the Archer units. Worth it? I would like to hear from you! On another note. I have uploaded a few Sun N Fun photos in my area of Europaowners.org. They include a visit to Deans house to check out his progress. Thanks in advance for any information on antennas. Brian Skelly Texas Europa # A276 TriGear See My build photos at: http://www.europaowners.org/BrianS ________________________________ Message 4 _____________________________________ Time: 12:17:03 PM PST US From: "Duncan McFadyean" Subject: Re: Europa-List: bad cold starts --> Europa-List message posted by: "Duncan McFadyean" <> Which in another language is torsional resonance. Every engine has this, especially with a larger flywheel (the prop) coupled by a spring (the face cam device at he front of the gearbox) to the crank. This natural resonance usually occurs at sub-cranking speeds and is not excited by the smooth constant-level torque supplied by the starter motor. The starting system is usually designed to crank the engine above the resonant speed. Once the engine starts to fire then, if this is at the resonant speed, the resonance is massively excited. Resonance absorbs a vast amount of energy so, even if the engine is weakly firing, it may not be able to "power through" the resonant band. So the problem could yet be one of the starter not spinning the engine fast enough to get through this low speed phase; Or improper adjustment of the preload of the "dog clutch" which effects the resonant frequency. Or different prop inertia. Duncan McF. ----- Original Message ----- From: "Pete Lawless" Subject: RE: Europa-List: bad cold starts > --> Europa-List message posted by: "Pete Lawless" > > David > > Yes that is exactly what it does. My engine started cold fine but would > not come up to idle speed. Ran as if only 2 cylinders were firing, very > rough with lots of vibration. It would take several attempts to get it > to run smooth. Once it had fired up once then it was ok for the rest of > the day. I believe it is the kick back that damages the sprag clutch > but the bad starting, going into what the Rotax dealer in the UK > describes as 'sub-idle' it the result. > > Regards > > Pete > > > -----Original Message----- > From: owner-europa-list-server@matronics.com > [mailto:owner-europa-list-server@matronics.com] On Behalf Of David > DeFord > To: europa-list@matronics.com > Subject: RE: Europa-List: bad cold starts > > > --> Europa-List message posted by: "David DeFord" > --> > > > > If it sounds like it is running on 2 cylinders then it could > > be sprag clutch. Have a look in the archive there is lots of > > stuff about this. I have just changed my sprag clutch after > > only 120 hours on a 912 ul. The problem was instantly cured. > > > > Pete > > Can a sprag clutch problem cause rough running after the starter is off > (i.e., sprag clutch not disengaging)? I have been ignoring the sprag > clutch/heavy-duty starter discussion, assuming that it referred only to > kickback and other problems while the starter was actively driving the > engine (problems which we haven't experienced). > > Thanks to all who have offered suggestions. We have carefully set the > clutch cables so that both chokes hit their limit stops at the same > time. We have also checked the temperatures of the exhaust pipes (both > by feeling and by EGT reading) after a few seconds of rough running, and > no significant difference was found between the port and starboard > sides. > > Today we tried replacing the fuel in the float bowls with fresh auto > gas. No help. > > After a few seconds of rough running, the port side carburetor sometimes > overflows fuel into the air box, probably because the float needle gets > shaken off of its seat. Cylinders 2 and 4 are then quickly flooded, > which can be overcome only by opening the throttle far too much. We'll > try starting with the fuel selector off, to see if we can avoid the > flooding. > > Dave DeFord > N135TD > > > -- > > > -- > > ________________________________ Message 5 _____________________________________ Time: 12:27:56 PM PST US From: "Duncan McFadyean" Subject: Re: Europa-List: Re:Wastegate sticking on 914 --> Europa-List message posted by: "Duncan McFadyean" Perhaps another case of "you've been told by the manufacturer that the engine may stop suddenly without warning". So if it does, its your fault either if you didn't expect it or didn't control the ensuing situation!! This culture seems to serve in lieu of a proper fix in the first place. Duncan McF do not archive ----- Original Message ----- From: "Graham Higgins" Subject: Europa-List: Re:Wastegate sticking on 914 > --> Europa-List message posted by: Graham Higgins > > After my prang which I believe was due to overboost from wastegate sticking, I > have been at a loss to understand Rotax thinking. The turbo charger wastegate > default position is closed - ie turbo operating fully unless otherwise > commanded by the electronic control system. If any part of that system fails, > there is risk of overboost, and major engine damage.They advocate warning > lights to show turbo surge, and if overboost is likely, simply recommend > "reduce power to acceptable limits, limit operations (land), and fix the > cause" > My question is why not have some more positive option for the pilot in this > situation than simply warning light(s). > Has anyone considered having a manual over-ride to open the wastegate when > the warning lights indicate overboost is likely? I would have had plenty of > power to fly clear of trouble on 80 hp. and avoided the severe damage to the > aircraft and myself,if I could have simply disabled the turbo, and used the > normally aspirated function of the engine. > It should not be too difficult a task to devise a cable attached to the > servomotor cable outer, so that the wastegate can be forced open if > necessary. I do not know what forces would be required, but it would need to > be greater than the servo motor to be of any benefit. > Has anyone else had similar thoughts, or done any research, or know the force > generated by the servo motor on the wastegate arm?? > I would like to have more options to do something about it when overboost is > threatening. > Graham Higgins in Oz. > 914, Mono, Airmaster, 98 hrs to prang, rebuilding, but wanting something > better before I fly again. > > Subject: Re: Europa-List: 914 Waste Gate Sticking > > > > --> Europa-List message posted by: "Fred Fillinger" > > > > > Upon departure, at about 1800' agl, the waste gate stuck > > > > > closed, the engine over boosted and snapped the crank. > > > > > John Lawton > > ________________________________ Message 6 _____________________________________ Time: 06:36:31 PM PST US From: SPurpura@aol.com Subject: Re: Europa-List: bad cold starts --> Europa-List message posted by: SPurpura@aol.com I AGREE,SOUNDS LIKE IT'S NOT SPINNING FAST ENOUGH AT STARTUP,PROBABLY A WEAK BATTERY. SAM N77EU ________________________________ Message 7 _____________________________________ Time: 06:55:49 PM PST US From: "Cliff Shaw" Subject: Re: Europa-List: bad cold starts --> Europa-List message posted by: "Cliff Shaw" I will be there. Cliff Shaw 1041 Euclid ave. Edmonds, WA 98020 425 776 5555 http://www.europaowners.org/WileE ----- Original Message ----- From: Subject: Re: Europa-List: bad cold starts > --> Europa-List message posted by: SPurpura@aol.com > > I AGREE,SOUNDS LIKE IT'S NOT SPINNING FAST ENOUGH > AT STARTUP,PROBABLY A WEAK BATTERY. > SAM N77EU > > > > > > > ________________________________ Message 8 _____________________________________ Time: 07:19:47 PM PST US From: Andrew Sarangan Subject: Europa-List: Archive site has moved --> Europa-List message posted by: Andrew Sarangan For those who visit my Europa email archive, the site has moved to the following address: http://www.sarangan.org/europa_forum/ Andrew Sarangan http://www.sarangan.org