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Mike Koerner

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About Mike Koerner

  • Rank
    Co-Pilot Member

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  • Location
    Palos Verdes, CA
  • Interests
    flying, soaring, sailing, climbing
  • Gender
    Male

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  1. Mike Koerner

    What are these three wires for?

    Vibration isolators would provide no benefit. The ignition units are solid state and have no moving parts. Furthermore, they're potted in plastic. The only part subject to vibration failure is the connector, wiring harness and mounting lugs. Just put them back the way they were when you found them. Mike Koerner
  2. Mike Koerner

    Humphreys close up for Mike

    Ed, On the bright side... you have more time to edit your pictures. This one is perfect. Thanks. Mike Koerner
  3. Mike Koerner

    CTSW Cruise Speed

    Jacques, Thanks for pointing me to the previous thread you linked where Tom Peghiny explained that "An elevator is called Hoen-rudder in German." Mike Koerner
  4. Mike Koerner

    T Coupler

    CT2K, It seems to work fine. Like I said, I should do some testing. Mike Koerner
  5. It's irritating how mediocre my own photos are in comparison. I'm going to throw my camera away. Mike Koerner
  6. Mike Koerner

    An actual video - Ken Burns effect! fun! lots to learn

    Nice Ed. Is that an avalanche in the nearest couloir of the last scene?! Maybe you should zoom in on that. Mike Koerner
  7. Mike Koerner

    Glider tape question?

    24, 1) Wings & wheels, a US sailplane parts supplier, carries several solutions for sealing control surfaces including mylar strips and 2-sided transfer tape or anti-peel safety tape that allows you to attach one edge of the mylar to the aircraft while the other rubs against the control surface. 2) Sailplanes use control surface seals like this all the time as they reduce drag by eliminating airflow across the hinge gap. You may be able to find a sailplane supply house closer to you, at least on your east coast, that carries the same thing. 3) I will let others, with more experience than I, address the question of whether a mylar seal on the elevator trim tab is normal. I just put a wide strip of tape across the top surface of the joint. I apply it with the stabilator in the up position (trim tab down) so that the tape is fully stretched. It is true that in any other position the tape will have a little kink in it, but the trim moves through such a narrow angle I can't believe that's significant. 4) I am very interested in the nature of your original trim tab issue. Did the pin through one of the hinges wear out? Mike Koerner
  8. Mike Koerner

    CTSW Cruise Speed

    Jacques, Why was the video you posted labeled "Ruderflattern" (which translates to "Rudder flutter"). The damage to the horizonal suggests excitation by the elevator trim tab or through the stabilator pivot. It seems unlikely that rudder flutter would excite the horizontal to such a degree. Mike Koerner
  9. Mike Koerner

    CTSW Cruise Speed

    Stinker, In your post on Monday you said you would use tracks at 180, 45 and 270 degrees. Those are not 120 degrees apart. As Scrapman said, if you use 180 degrees as one of your tracks, the other two should be 60 and 300 degrees. Mike Koerner
  10. Mike Koerner

    T Coupler

    CT2k, As another data point, my CT2k, manufactured in 2004, has no external static port either. The static ports on my altimeter, airspeed indicator, EFIS and transponder mode c encoder are all open. They see cabin pressure. Tom, You may be right about the resulting static pressure being low. I have never noticed an altitude discrepancy, but I have always felt that my airspeed indicator, though seemingly accurate at low speeds, was a bit optimistic at high speed. There are lots of cabin air leaks including through the firewall electrical wiring hole (which would probably be above static pressure, around the door (below), through the wing root (???), and through the window vent (below if closed, above if open). But the biggest leak of all is undoubtedly the hole in the back of the fuselage, which is certainly below static pressure. I should do some tests to determine the significance of this design; recording indicated altitude as a function of speed while maintaining constant GPS altitude and recording indicated airspeed vs. GPS ground speed with varying speed at a constant heading and altitude. And if the discrepancies are significant, I should do as Jacques has done and add a proper external static port. It would certainly make my bi-annual transponder calibration more straightforward. Mike Koerner
  11. Mike Koerner

    Battery and jumping it

    Forgot to add a Poppy picture. This is north of Lake Elsinore. There are thousands of people strolling along the dirt road in the center of this photo. The freeway just below this frame is jammed with cars. Everyone has come out to see the flowers. Mike Koerner
  12. Mike Koerner

    Battery and jumping it

    Sleepy; Sorry to commandeer your topic. Ed, Jacques, Roger; Thanks for your comments and help. I don’t think my prop has ever turned backwards, at least not more than 5 or 10 degrees. What I’m calling a kickback is exactly what is depicted in several of the starts in the video Jacques provided. The engine comes to a very sudden and forceful stop. It’s as if one of the chambers fires and reaches peak pressure before top dead center. If so, that implies at least one of the following: 1) That cylinder fired too early 2) The burn rate is unusually fast 3) The engine was turning over unusually slow Though number 1 & 2 seem unlikely, my most recent experience cannot be due to number 3. As I explained, the jumped starts when this occurred were very energetic, the fastest I've ever seen the engine turn. The times I typically see these "rough" starts is when the engine is really cold, not just a cold start, but a very cold start. The two starts I referred to were sub-zero and single digit degrees F but it has happened at less severe conditions as well. I have seen it under such conditions since as early as 2006. And I have no doubt that what is happening is not good for the engine. But so far I have not had to replace any engine components (I'm at 1800 hours now) and as I say, it still starts perfectly under more normal conditions. (I added a couple more starts on a trip to see the wildflowers this weekend.) Dick, I think you’re right that these engines, or at least mine, don’t like to be started cold without pre-heating. Is this true of the 912is fuel-injected engines as well? What about planes with soft-start modules - can they get by without a preheat in cold climates? Since I intend to travel year-round, and airports don’t have power plugs on the flight line. I need to find a cheap, light-weight, safe, effective, quick way to heat my engine. I used to have a little backpacking stove that burned unleaded gasoline. I could fill it from the gascolator. It’s certainly not safe (it burned a hole in my tent once) but 4 out of 5 is not too bad. Mike Koerner
  13. Mike Koerner

    3D Printed (FDM) Cabin Plugs

    Stinker, The compound curves beg for an additive manufacturing process. You just need to invest in some fancy digitizing equipment. The part you made is beautiful anyway. Mike Koerner
  14. Mike Koerner

    Battery and jumping it

    As mentioned in a previous post, I recently got back from a trip to Ohio which involved scrapping snow and ice off the plane for a couple of cold morning starts after the plane had be left out overnight. One, in Wooster, Ohio with the temperature at takeoff was just below 0 F and the other at Canadian, Texas in the single digits. My Odyssey battery, which had been (and still is) working fine out of a hangar in Southern California, was able to turn the engine over each time, but not fast enough to fire the ignition. I don't think that's too surprising. Lead acid batteries lose half their energy at 0 F, and mine was probably soaked to a colder temperature than that. The folks at Smith County brought a ground cart with big batteries out of a warm hanger. I set it to 12 volts and hooked the clamps to the positive lead sticking out from under the cowl and to the exhaust stack as a ground. The engine spun faster than it's ever spun before, fired right away and kicked back as it often does when starting at cold temperatures (I don't have a soft start). The kickback stopped the prop but the starter continued to spin on its own. This last part is the part that's surprising to me. Usually the kickbacks stop the engine and the starter. It happened 2 more times in Ohio before I got a good start. Then it happened again the next day with a plug-in jump charger at Canadian; the engine spun energetically, fired, kicked back and disengaged the starter. When disengaged the starter sounds like on a car with a low battery or defective starter solenoid. I've never had this happen before (or in several flights since) on my airplane. In the Illustrated Parts Catalog I see that there is a sprag clutch between the free wheel gear and crankshaft. Apparently, it was slipping or not engaging after these kickbacks during particularly energetic starts. Is this normal or an indication of a problem with the sprag clutch? Mike Koerner
  15. Mike Koerner

    Warm up question?

    Hi Buckaroo, I don't think you should fly if you can't get the oil temperature up. My handbook lists 120 F as the minimum oil temperature. I think running the engine at high rpm at lower oil temperatures will cause the oil filter bypass to open, which means you're not filtering the oil anymore. That's going to increase wear on the engine. Also, the plugs are more likely to foul when the engine is cold. I'm very surprised that you are not getting higher oil temperatures with the radiator blocked. Is this at 2500 rpm? My handbook says to keep the rpm below 2000 for the first 2 minutes but after that I can run it up to 2500 rpm until it gets to 124 F, at which point I can go to full throttle. As Ed suggests, you might try pushing the rpm a bit higher as you get close to 124 F. It makes sense that progressively higher rpms might be acceptable as the oil viscosity is getting progressively lower. I took off from Ohio last week with the plane left out overnight and the OAT below 0F at takeoff. The battery was a problem to be sure, but with 3 vertical strips of 2" wide tape down the radiator I was able to get the oil temp up into the 140F range. With a negative 2000-foot density altitude the aircraft performance was wonderful, but I did have to be careful to maintain power during descents. Mike Koerner
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