Activity Stream

Posts Activity Stream

  1. marcusofcotton


    Jenki,

    Belleville washers are washers that are not flat, they are cupped, and if not made of spring steel, have some spring to them so they keep pressure on the bolt/nut when they are torqued down correctly.  The amount of pressure can be varied by changing how much torque is applied to the bolt.

    Mark

     

     

    Jenki,

    Belleville washers are washers that are not flat, they are cupped, and if not made of spring steel, have some spring to them so they keep pressure on the bolt/nut when they are torqued down correctly.  The amount of pressure can be varied by changing how much torque is applied to the bolt.

    Mark

     

    Oh, thank you, we call this spring washer, split lock washer ... now I understand

    No Jenki, not a split lock washer, these are belleville washers. Nested stack increases the pressure available, inverted stack increases the range of operation. Nested and inverted increase both. They are not designed to be tightened down flat. Do an internet search on them.

    https://www.mcmaster.com/belleville-disc-springs

    P.S. I missed that others had already answered... had an image added too but it didn't make it.

     

     

  2. Turbo


    No, Belleville spring and split lockwasher are two different things.  Belleville spring, if laid on a flat surface, is raised on the inside relative to the outside.  It's like a shallow cone, with elevation varying with radius only.  When compressed, the outer edge is in tension, and the inner edge is in compression.  It's a nonlinear "softening" spring; spring rate decreases with deflection towards flat.

  3. Cloud Dancer


    They hung them upside down because of too little offset on the Rotax gearbox and so they could be cowled like a conventional airplane. If the engine was upright the oil would accumulate in the bottom of the engine because the fuel/oil charge enters through the side of the crankcase and not the head. 

    The gearbox can be mounted in four different positions. Too bad nobody makes an intake manifold to fit  a down draft carburetor on the Rotax engines. Then it could be mounted on it's side with the intake on the top and the exhaust on the bottom. Any fuel mix dripping through when it's not running would drop out the exhaust ports if it happened to make it past the rotary valve.

  4. Turbo


    Just completed the mod to correctly relocate my EGT probes.  Again, thanks to all, especially Vance.  I'm keen to fly it to test it out.  Looking at my carbs, it appears the previous owner knew what he was doing, setting it up slightly rich on the part-throttle needle, hanging 'em high, and with the next size larger (than Rotax recommends) needle jets.  It will be interesting to see what results.  With no cabin heat, though, fear of the dreaded freezerburn keeps me on the ground for now.  Plus, the days are so darn short, and my bird doesn't live at the airport.  Temporal overhead for launch is a bitch.

  5. 1avidflyer


    Not really just then.  just taxied him around in it.  The friend of mine that passed away a year ago did fly with me  a few times though, and he was about 6' 1" and weighed about 240.  We filled up the space for sure.  Maybe that's why I like the idea of widening the fuselage.  JImChuk

    1 person likes this
  6. PW_SD


    Hello Gents,

    I have a pair of Avid STOL wings for sale here in San Diego.  

    Age and full condition unknown, they will require restoration, including rib-tail flaperon attachments.  Flaperons not included.

    Asking $500 for the pair and motivated to clear some space!  I have jury struts available as well, separately.

    Email or PM me with any questions.  Will be posting to Barnstormers soon.

    Thanks!

    Phil

     

     

    Avid STOL Wings.JPG

  7. Jenki


    Jenki,

    Belleville washers are washers that are not flat, they are cupped, and if not made of spring steel, have some spring to them so they keep pressure on the bolt/nut when they are torqued down correctly.  The amount of pressure can be varied by changing how much torque is applied to the bolt.

    Mark

     

    Jenki,

    Belleville washers are washers that are not flat, they are cupped, and if not made of spring steel, have some spring to them so they keep pressure on the bolt/nut when they are torqued down correctly.  The amount of pressure can be varied by changing how much torque is applied to the bolt.

    Mark

     

    Oh, thank you, we call this spring washer, split lock washer ... now I understand

  8. Chris Bolkan


    That's my friend Jeromie.

    He was building a carbon fiber plane. It consisted of a carbon fiber fuselage. Murphy Rebel wings I think, aTitan tornado full flying empanage and a kitfox7 firewall forward. He got a lot of the way done but abandon the project and ended up just buying a clipped wing piper. So he is parting everything out. 

    He has the complete KF7 FWF setup minus engine. This exhaust is part of that setup. i was hoping I could use it on my Fat Avid, but it won't work.

    Anyway he now has a lot of random stuff for sale and what doesn't sell will be thrown away.

  9. Chris Bolkan


    That's my friend Jeromie.

    He was building a carbon fiber plane. It consisted of a carbon fiber fuselage. Murphy Rebel wings I think, aTitan tornado full flying empanage and a kitfox7 firewall forward. He got a lot of the way done but abandon the project and ended up just buying a clipped wing piper. So he is parting everything out. 

    He has the complete KF7 FWF setup minus engine. This exhaust is part of that setup. i was hoping I could use it on my Fat Avid, but it won't work.

    Anyway he now has a lot of random stuff for sale and what doesn't sell will be thrown away.

  10. Chris Bolkan


    Guys, you are going to chase shimmy all day long re-arching springs to change castor angle in hopes of eliminating it. The only real solution is enough adding enough friction in the back and forth movement of the wheel (resistive damping) to critically dampen the resonance. Shimmy is a resonance. Just sayin.....

    The trick is adding enough friction in the back and forth movement of the wheel to kill the shimmy but still be able to overpower the friction with steering springs..

    That's why some of the really big tailwheels have gone away from steering springs altogether, because it takes so much friction that steering doesn't really work anymore and you have to steer with differential breaking.

     

  11. 1avidflyer


    Murphy aircraft and others have used fiberglass tailwheel springs.  I also made one for an Avid, but it cracked when I was taxing with a 275 lb guy in the other seat.  Picture is not of mine, but one I pulled off the web.  JImChuk

    Image result for fiberglass tailwheel spring
     

  12. NorthIdahoAvidflyer


    They hung them upside down because of too little offset on the Rotax gearbox and so they could be cowled like a conventional airplane. If the engine was upright the oil would accumulate in the bottom of the engine because the fuel/oil charge enters through the side of the crankcase and not the head. 

  13. Cloud Dancer


    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.  

    And I still don't understand why we hang these things upside down. I'd rather have the oil accumulate on the top of the piston.

  14. Cloud Dancer


    Once you add up the parts, your right, the weights are very similar. I do like the idea of getting away from two stroke oil. The people running them in the past seem to have almost as many problems as people running 2 smoke engines.  http://www.teamkitfox.com/Forums/showthread.php?t=7745  I'm sure if I had one laying around I'd have to try it. Price wise they seem like more money without any savings in weight, fuel consumption, or usable horsepower in Avid Flyer type aircraft. A reduction unit would take advantage of the extra horsepower but then your taking an additional hit in the weight department. Their website lists propellers for their engines and there are none longer than 60" and that will restrict performance in our style aircraft. The lower R.P.M.'s is something that should mean an engine that lasts longer but it has not been working out that way.

  15. wypaul


    Anyone with a simple press can re-arch the spring.  I would only do that once and then replace when it loses its arch again. The spring will break if re-arched more than a couple of times.  I did it myself a couple of times before it broke causing a fair amount of damage to the rudder.  I suspect that the original MK IV spring is nothing more than cold rolled steel.  I am now using the long leaf, one leaf, of a Super Cub spring which is holding up great.

  16. skypics


    I fought the same issue with my MATCO single fork tail wheel.

    I found that the shimmy was worse with a passenger in my MK 4 Avid. This is because the tail wheel spring would flatten more with the weight throwing off the geometry.

    I found that the tail wheel had worn parts. Namely the triangle shaped part that the "wings" rest on when in the steering mode was worn so the tail wheel broke into swivel too early. Also MATCO sent me those washer that are bent...can't remeber the name...to put under the top nut. And finally I ran my rudder springs tighter.

    I am seeking a shop that can rebend my tail wheel spring back to the original shape, but am not haveing an shimmy issues.

    John M

  17. marksires


    Jenki,

    Belleville washers are washers that are not flat, they are cupped, and if not made of spring steel, have some spring to them so they keep pressure on the bolt/nut when they are torqued down correctly.  The amount of pressure can be varied by changing how much torque is applied to the bolt.

    Mark

     

    1 person likes this
  18. skypics


    FWIW here is my feedback on belly mounts vs cheek mounts.

    I currently fly a MK4 with a Jabiru 2200 so no water issues, but prior to the MK4 I flew a model B that came with a side mounted cooler that neve quite made the grade so I installed a belly mount in series with the side mount which cooled properly. Here's what you need to consider...

    Usually the belly mount is mounted somewhere between the main gear or maybe even a bit forward. 

    You will have to deal with the fact that the hot air from the muffler goes directly back to the belly radiator and so does not cool as well as it could.

    What I did to solve this issue was to mount the belly radiator 2 inches below the fulelage and then fabricated a sheet of aluminum that directed the heat from the muffler up over the cooler.

    A year back a friend bought a MK4 nose dragger with a belly mount encased in a plenum like a P51. We could never get the heat down to an acceptable level and then I remembered the issue with heat from the muffler. Fortunately another friend had removed his 582 and installed a Jabiru 2200 so he had two cheek radiators for sale. 

    We removed the belly mount and installed the cheek cooler.Problem solved along with drag reduction which gave us an extra 2-3 MPH cruise.

    The belly mount will need more coolant (weight) due to the extra length of the hoses.

    Stay with the cheek mount for a simpler solution.

    John M

     

    1 person likes this