---------------------------------------------------------- Kolb-List Digest Archive --- Total Messages Posted Sun 09/07/08: 7 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 04:07 AM - resonance (Ted Cowan) 2. 04:48 AM - Re: resonance (Jack B. Hart) 3. 05:11 AM - Re: resonance (Ralph B) 4. 06:20 AM - Re: LSA (George Alexander) 5. 06:28 AM - Re: resonance (robert bean) 6. 06:29 AM - Wingnuts Fly-in (Jack B. Hart) 7. 11:43 AM - Re: resonance (Jack B. Hart) ________________________________ Message 1 _____________________________________ Time: 04:07:14 AM PST US From: "Ted Cowan" Subject: Kolb-List: resonance Will try to answer each as I can. Does it do it when tied down, doing a static runup? 'does it anything over an idle -- audible tied up, flying, all rpms. Did you close the rear windows? ' rear windows are open' Is the fabric tight on top of the wings, inboard near the engine? 'fabric vibrates but have applied tapes, foam, pressure on fabric and does not stop the noise - engine producing noise' Did you check gear box to see if it was shimmed correctly? 'gear box shmming seems to be the last hope. - just gotta get someone to take it down and be able to reshim it - seems I may have to fly to Ronny Smiths to get it tried.' Has anyone else had this problem with a SS and 912? 'have heard of several on Mk models. One on another plane that just plain drove the pilot crazy, sold the plane and they took the 912 off, solved the problem' Has anyone else had this problem with SS and other engine combinations? 'Robert Been sent email stating he has some problem similar but was using 3 cyclinder (hurth?) and 3 blade. tore up gear box bearings' Has anyone else had this problem with other aircraft and engine combinations? Dan Horton's 3/4 scale Jenny with 3 cyl Suzuki engine did this. Never did figure out why it did it. 'seems like this is the answer so far' Ronnie Collins SS did it. Fabric had been rib stitched by builder. Stitches were failing on top of wings inboard near the engine. Caused by drumming from prop. 'I believe Ronny had 582 rotax on it at the time. I have tried no spacer, 4" spacer and now have 2" spacer that seems to work best. Have padded up down and all around everything back there I can. Helped. Bought an ANR set for my military helmet. Best thing yet. Still hear the noise but at least I can use the radio crystal clear. Best two hundred bucks I ever spent. Oh, yeah, I never have to worry about the ANR Bat going dead. It will go dead as soon as I am about one mile from a busy airport during an airshow. Getting good at changing the bat with one hand. Many thanks to the one who put me on to it on the list.' Okay, put your thinking caps on tight. Hope a qualified rotax gear box man is at the homecoming. That is my last hope Obeywan. Ted Cowan, Alabama, Slingshot. ________________________________ Message 2 _____________________________________ Time: 04:48:37 AM PST US From: "Jack B. Hart" Subject: Re: Kolb-List: resonance Ted, What propeller are you using? Jack B. Hart FF004 Winchester, IN ________________________________ Message 3 _____________________________________ Time: 05:11:55 AM PST US Subject: Kolb-List: Re: resonance From: "Ralph B" I haven't noticed any resonance on the Kolbra 912. It has a tapered Warp-Drive prop pitched high for cruise. You might add more pitch and see if the resonance goes away. Ralph -------- Ralph B Original Firestar 447 N91493 E-AB 21 years flying it Kolbra 912UL N20386 0 years flying it Read this topic online here: http://forums.matronics.com/viewtopic.php?p 3026#203026 ________________________________ Message 4 _____________________________________ Time: 06:20:35 AM PST US Subject: Kolb-List: Re: LSA From: "George Alexander" tc1917(at)bellsouth.net wrote: > I may be wrong here, correct me please, but I was under the impression that > an AP-1 rating was a lesser rating than AP-2. In other words, if you had an > AP-2, you were qualified in tail dragger AND nose wheel. You were stepping > up a notch. Same as if you are rated for over 87 knots, you were > automatically qualified for the lesser of the ratings. Any other way of > interpreting it would be ridiculous. Ted: For Sport Pilot, no "ranking" of LSA sets. The practical test for Sport Pilot gets you a set endorsement for the aircraft used. Have to do additional work for the others you want/need. Differences in handling characteristics is the reason given for the additional requirement(s). >From the FARs....... Sec. 61.323 How do I obtain privileges to operate a make and model of light-sport aircraft in the same category and class within a different set of aircraft? If you hold a sport pilot certificate and seek to operate a make and model of light-sport aircraft in the same category and class but within a different set of aircraft as the make and model of aircraft for which you have received an endorsement, you must- (a) Receive and log ground and flight training from an authorized instructor in a make and model of light-sport aircraft that is within the same set of aircraft as the make and model of aircraft you intend to operate; (b) Receive a logbook endorsement from the authorized instructor who provided you with the aircraft specific training specified in paragraph (a) of this section certifying you are proficient to operate the specific make and model of light-sport aircraft. -------- George Alexander FS II R503 N709FS http://gtalexander.home.att.net Read this topic online here: http://forums.matronics.com/viewtopic.php?p 3030#203030 ________________________________ Message 5 _____________________________________ Time: 06:28:19 AM PST US From: robert bean Subject: Re: Kolb-List: resonance > some notes to clarify: > Has anyone else had this problem with SS and other engine > combinations? > 'Robert Been sent email stating he has some problem similar but was > using 3 cyclinder (hurth?) and 3 blade. tore up gear box bearings' > 3 cylinder is also a suzuki. I'm not using a gearbox but I do suspect the 3 blade was having a high freq problem with the engine in the 5000 rpm range and damaging the shaft bearings in the raven cog belt drive. Couldn't hear it or feel it but three times in a row the carefully set up, greased and torqued bearing stack lost their torque load and began to spin the stack. -not good. Now with the warp 2 blade I have run all summer with an audible rum rum and the redrive has performed perfectly. This is as much a confidence issue as an annoyance. My next experiment will be a 2 blade with less inertia. > > > Dan Horton's 3/4 scale Jenny with 3 cyl Suzuki engine did this. > Never did figure out why it did it. > 'seems like this is the answer so far' > I wonder if he found a solution? Bob Bean > ________________________________ Message 6 _____________________________________ Time: 06:29:05 AM PST US From: "Jack B. Hart" Subject: Kolb-List: Wingnuts Fly-in Kolbers, Yesterday, I flew a little cross country from Winchester to just south of Nulltown to a little ultra-light field tucked in between a line of trees next to a river. They have a yearly hog roast. When I parked I was next to another Kolb. It turned out to be Dick Graham who hangars at Green Acres next to New Lebanon, Ohio and a member of this list. My wife drove down, and we had lunch. I had a great time talking to a couple of fellows who are in the building process. It is an interesting little strip, in that you always land to the north up hill and take off to the south downhill. The trees pretty well blank the wind until you fly beyond them or up over them. Stayed until 2pm and then headed back home through the thermals. The following is from my flight log: September 6, 2008 - Flights 708 & 709 - one hour, 56 minutes, 46 seconds - 252:28 tt, Victor 1+ 172:28 burned 3.60 gallons for an over all fuel burn of @ 1.85 gph. Flew from I22 to 73II, Nulltown, 43 miles point to point. Louise drove down to carry gas. Had lunch and flew home. On the way down I had a tail wind and cruised at 5,200 rpm. Burned 1.5 gallons in 48 minutes 12 seconds for a 1.87 gph fuel burn. On the way back I ran the engine 5,200 rpm, burned 2.1 gallons over one hour, 8 minutes 34 seconds for a 1.84 gph fuel burn. Averaged 23.8 mpg overall, and 28.7 mpg going, and 20.5 mpg coming back. Before leaving, I installed the new valve, and new gage. I did not have the gage converted to a differential manometer so I plugged the high pressure line so that the throttling valve out but still referenced the pressure under the wing at the root tube. The gage showed a couple inches of water right away at low engine speeds with the valve wide open???. The indicator needle was a little nervous but I believe that was due to the fact it was referencing cockpit air. If this continues, I will add a critical orifice to the inlet. I ran the EGT1 up to 1,300 degrees F and EGT2 ran about 50 degrees F higher. Flew at 1,000 to 1,500 in 55 to 60 degree F air to keep the coolant temperatures below 180 degrees F. I left Nulltown, at 2pm and so I had a rough ride home. The engine ran well at all cruise speeds. Upon landing, I opened the throttling valve to richen the mixture. More tests must be run to see if this is necessary. Very little to no ETG increase due to nosing down and unloading the propeller while in thermals. The only difference I noticed in switching vacuum sources it that there was a marked change in engine idle. The bleed air in the throat leaned out the idle, so that minimum idle is below 1,800 rpm. Engine did not quit upon throttle closure. I had to use the grass runway, at I22 because they are working on the asphalt runway, sealing etc. Landing at Nulltown is always interesting, as it is up hill and in between trees. Today landing was into the wind, so one could get the speed down. Departure is down hill, and when you come out from in between the trees, it gets interesting. Brought the new gage home so that I can lighten and change it into a differential manometer. Need to run more tests. This is very encouraging. Fly safe! Jack B. Hart FF004 Winchester, IN do not archive ________________________________ Message 7 _____________________________________ Time: 11:43:59 AM PST US From: "Jack B. Hart" Subject: Re: Kolb-List: resonance Ted, Are your wing struts streamlined? Jack B. 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