View Poll Results: Why is jump so rare?

8. You may not vote on this poll
  • Nobody wants it

    1 12.50%
  • Initial cost too high

    4 50.00%
  • Too much maintenence

    1 12.50%
  • I think it's dangerous

    2 25.00%
Multiple Choice Poll.
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Results 131 to 140 of 142

Thread: Jump Rotorhead Dynamics

  1. #131
    Ok watched a youtube on replacing a motorcycle clutch see that the throwout bearing is called a lifter. How are you accessing this lifter to lift the pressure plate. No hurry just curious. Taper lock is solid. We sometimes had clearance issues when we would plug gear mounted hydraulic motor into engine pto port. You won't have that problem.
    Ed L.

  2. #132
    Ed -
    The "lifter" rod travels through the center shaft and pushes the pressure plate to disengage the clutch. Since I'm blocked by the crankshaft pulley and the engine, I'll have to pull the pressure plate from the outside instead of pushing it from inside the shaft.

    The problem with taper-lock is just getting it right. Don't have factory made parts to just put together. Will have to grind the taper inside the gear so no threaded holes in the gear, then turn down the taper-lock fitting to match the gear and jury-rig a way to lock the two together. Not a done deal for sure.

    Leaving for California on Tuesday for grandson's wedding, great family times, so will be away for a couple of weeks.

  3. #133
    You still alive, noticed you have a 1/4 million views on your thread so must be some interest here.
    Ed L.

  4. #134
    Hi Ed -
    :-) Yep, still alive. Hope you and yours have stayed well. Have thought of you frequently but wanted to have something more productive to tell. And yeah, the view count is mind bending, especially considering the dearth of new info.

    Too busy, too cold, lotta family. Still - working when I can, and warmer weather will help. Have finally successfully mounted the motorcycle clutch gear under the rotorhead, spent a lot of time trying to use an automotive spiral bendix at the rotorhead to simplify engagement, but failed after much effort to adapt the gears, so working on manual engagement, which is drawn up but still have to build it, and make it work. Have decided to mount the hyd motor on the mast at about the engine level to reduce the weight and drag at the rotorhead. Have the adapter made to mount the clutch on the engine crankshaft. Still have to make the framework to carry it all, not to mention the clutch to pump gear work, which I think will be easier than at the head. One thing about this kind of a project - it sure does teach you patience.

  5. #135
    Glad to hear your still making progress on all fronts. Ed L

  6. #136

    Join Date
    May 2019
    9106 Hwy 45N Belhaven NC Eastern Coast
    I have 1,000ft grass strip beside my
    ome. i t
    hink it would a hot set up on monarch butterfly. make my strip seem a longer
    buy the way does anywone have any experience with the Monarch Butter Fly machine?

  7. #137
    PRA Secretary JOHN ROUNTREE 41449's Avatar
    Join Date
    Jun 2010
    San Diego Ca.
    Blog Entries
    Good on YA. Keep on keep'n on.

    PRA started an open source program with San Diego University and this year added San Diego State University senior engineering departs working on two prerotators and a G impact fuel cut-off system this year.

    But next year will reach out to UCLA and others and going to ask all the colleges next year to design another PRA open source project for two jump take-off systems using two 18 HP electric motors and Dick Degraw advised you only need 30 HP and a Robinson rotor head and it should work.
    These are going to be even more fun projects with Dick's help, so there is hope for those who want or need jump take-off capability. PRA will buy in volume to reduce the cost to all and hold in inventory for our community all of the open source projects.
    Last edited by JOHN ROUNTREE 41449; 06-02-2019 at 11:45 AM.
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  8. #138
    John - several latest posts have disappeared - can you restore them? Jim

  9. #139
    John - several latest posts have disappeared - can you restore them? Jim

  10. #140
    Jim - so what did you post?

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