Activity Stream

Activity Stream

  1. Jenki added a post in a topic MATCO Tail wheel shimmy   

    Sorry, can you explain more deeply "resistive damping" ?
    I am not native so even "belleville" washers are something I don't know exactly ...
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  2. Jeromef added a topic in Avid fox flyers pics and vids   

    A 1900's board game
    On the risks of aviation, not totally obsolete!

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  3. Turbo added a post in a topic Pull start setup   

    Here's a close-up of the pulley mount, from the cabin side of the firewall.  The big black thing is the handle.

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  4. 1avidflyer added a topic in For Sale and wanted, you got it, I want it   

    Kitfox 912 SS muffler on ebay
    Just saw this on ebay.  Richland Wa.  Isn't that close to you Chris?  JImChuk
    https://www.ebay.com/itm/Kitfox-SS-912-Exhaust-System/264081402236?hash=item3d7c7a697c:g:qrUAAOSwEp5cDaqJ:rk:4:pf:0
     
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  5. 1avidflyer added a post in a topic Kitfox IV 912 exhaust   

    I just ran across this ebay add for a Kitfox muffler.  Maybe the pictures will show what you need to see.  Or maybe someone wants it and buys it.... JImChuk
    https://www.ebay.com/itm/Kitfox-SS-912-Exhaust-System/264081402236?hash=item3d7c7a697c:g:qrUAAOSwEp5cDaqJ:rk:4:pf:0
     
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  6. BryceKat added a post in a topic Little Progress   

    Good job!
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  7. Allen Sutphin added a post in a topic covering   

    Finally got my wings finished up thru the filler coat, or course a lot of time was spent installing new tanks and a couple of ribs and working part time. Will wait till I finish covering everything prior to painting which only messes up the shop once. I really like the Stewart System better than Poly Fiber cause now I can actually walk in a straight line from the shop to the house. Well, straight for someone in their 60's.
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  8. Shipl14 added a post in a topic Little Progress   

    Actually I had been considering modifying the rudder pedals to help keep my feet in the right spot.
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  9. Turbo added a post in a topic Soggy Plugs   

    Oh, BTW, and returning to the original theme, I pulled the plane out of the garage for a little testing and, after almost 2 months of inactivity, the engine wouldn't start.  Pulled the plugs and, you guessed it, the electrodes of even the extended-tip plugs were covered in oil!  Gotta fly more often!  Working on a cabin heater, among other things.  
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  10. Turbo added a post in a topic Soggy Plugs   

    Testing can reveal important physics.  I have prior experence with surface tension effects, so not suprisingly my intuition was correct.  Once a paper filter is saturated with fuel or oil, any water coming along cannot saturate the paper, and becomes trapped.  Once the amount of accumulated water is such that it becomes able to cover all of the paper media, the pressure drop required to force that water through goes way up.  That is calculable once the pore size is known.  Good thing, Leni, that your fuel pump was strong enough!  In the pic below, I first saturated the filter in fuel, then added water on the upstream side.  The horizontal line visible in the picture is the water surface.  That water is trapped.   Accordingly, I have removed my inline paper fuel filter from behind the seat, then installed a fine screen filter (larger pore size), but placed downstream of the "header tank" gascolator, where it is protected from water.  The little screen filter was sized for smaller engines, but inline testing at full throttle showed its pressure drop to be negligible.  My oversize paper oil filter is located where it is easily inspected and replaced, but I really expect little or no atmospheric water to thermal-cycle-pump its way into my oil tank, thus ultimately piling up against my oil filter.  By-the-way, I also flow-tested that filter in oil, and it passed.
    So Leni & Vance:  I hear you, my friends!  No offense intended.  It's just a matter of how I process information.  As an old airplane engineer, you can trust that I beat the holy schidt out of the problem, per well-established tradition!  I too am very keen on my prop not stopping unexpectedly!

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  11. NorthIdahoAvidflyer added a post in a topic Another Forced Landing - Mine   

    The Rotax 582 is 64 horse 110 pounds dry. 
     

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  12. NorthIdahoAvidflyer added a post in a topic Cabin Heat   

    The shipping weight of the 7KW is 18.74 pounds. That better be one heavy box.

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  13. Cloud Dancer added a post in a topic Cabin Heat   

    At 8000w your going to notice the things working even in Alaska. What do they weigh?
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  14. Cloud Dancer added a post in a topic Another Forced Landing - Mine   

    You must be thinking of the Rotax 912 weight, the 582 is listed at 64 pounds and the Jabiru 2200 is listed at 138 pounds.
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  15. Chris Bolkan added a post in a topic MATCO Tail wheel shimmy   

    Hi Larry! There is no question changing castor angle can affect shimmy, and it is possible in some cases (maybe a lot of cases i don't know) to greatly reduce/eliminate shimmy by changing castor angle. However it didn't work for me when I tried a very large tailwheel tire. The particular tailwheel I was using did not incorporate any resistive damping by design. When I went to the large tire the shimmy began.
    Trying to solve the problem, the designer built me various tailspring sockets to change castor angle. i was using a stinger type spring which made changing castor angle relatively easy by changing the spring socket angle.  I tried various castor angles from negative to neutral to positive. The effect on my tailwheel of changing castor angle was that with negative castor angle it would shimmy continuously. With positive castor angle it would shimmy violently but would then suddenly track without shimmy. But it still shimmied and was violent. The large tailwheel would ALWAYS shimmy under one condition or another until we applied resistive damping.
    He finally modified the design of the tailwheel to add resistive damping and that eliminated the shimmy. And with adequate resistive damping, It did not matter what the castor angle was. it did not shimmy
    I think that is why at least one newer manufacturer of really big tail wheels has eliminated steering springs altogether and uses tons of resistive damping in much the same form as Vans does using belleville washers to eliminate shimmy on their nose wheels. Vans specifies something like 10lb of force required to move their nose wheels back and forth. This resistance critically dampens any resonant frequency in the system. i think we have to look at tailwheels the same way.
     
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  16. sky4play added a post in a topic Little Progress   

    Slow and steady...wins the race. Looking REAL Good. Keep at it..
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  17. akflyer added a post in a topic Kitfox Newbie   

    Any good sled shop can reseal it for you.  I have done 4 or 5 582's myself.  The rebuild manual is on this site and the dvd "deep inside your rotax" pretty much walks you through it.  Buckchop on here is in Fairbanks and has a shop he used that resealed his engine.  I don't know anything on the other shops up there.

     
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  18. NorthIdahoAvidflyer added a post in a topic Little Progress   

    Oh and BTW. It looks great. I need to come visit you now  Keep up the good work. 
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  19. NorthIdahoAvidflyer added a post in a topic Little Progress   

    Skypics is right. I about ground looped my plane once when my foot slipped in behind that center bar while trying to get a landing straightened out. That was a bad design. I am going to put a fence on the peddle to give my foot an edge to set against so it wont slip off. 
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  20. jacksonbrowne added a post in a topic MK IV Aerobat speedwing spar gouge/repair   

    Agreed; it was meant as a quick-and-dirty visual for suggestions, certainly not for any kind of stress analysis or engineering purposes.  
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  21. skypics added a post in a topic Little Progress   

    Now might be a good time to figure out how to get more foot room on the pedals. That lower crossbar on the firewall frame will interfere with how much of your foot can fit on the brake pedal.
    I wear a size 9 and I can oly get my tip toes on the top of the brake pedal. If I could get the ball of my foot up om the top of the pedal  I could get better braking.
    Also it is possible to get ypur toe between the top of the brake pedal and that cross bar. 
    Avid MK4 
    John M
     
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  22. Teal added a post in a topic Yamaha Apex Skytrax Adapters   

    Hello all, Just a short update here. The Skytrax gearbox has been doing great during flight testing with only a few refinements that will be added to the production boxes like a sight level gauge snd slightly larger sump area. IF you didnt follow the Stol drag a few months back Steve Henry posted the second fastest time behind the 680hp turbine powered plane they call draco. In parrelel to Steves testing Thomas Hauklien of edge performance in Norway will start Dyno testing with a Turbo charged Apex. The goal is to get some 300hp sustained runs with and without the clutch and tear it down as nd measure and inspect parts. 
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  23. Snipe added a post in a topic Merlin GT   

    Kl1lz tell us about what you bought. How do you like it so far
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  24. Jenki added a post in a topic MATCO Tail wheel shimmy   

    I am trying to find detail ... but nothing better then this

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  25. Jenki added a post in a topic MATCO Tail wheel shimmy   

    Maybe you can recognize system how tail spring is fixed to fuselage.

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