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Thread: Hand propping a PPonk 470-50

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    Question Hand propping a PPonk 470-50

    Can an operator [relatively] easily hand prop a PPonk 470-50 , AKA O-520 with 7.5:1 pistons? Bear with me, as I imagine some readers might consider this a crazy question.

    As I'm at around 1,500 hours on my 470R, I've begun to plan for the next engine. I believe it's going to be a PPonk done with a 520 case and 7.5 pistons (lower compression). I have had to hand prop big engines before to keep from spending the night in the boonies, so expect the same could happen in the future.

    I don't know what the piston compression is on the 9-cylinder P&W R-985 on a Beaver, but I've hand propped those numerous times without crazy amounts of difficulty. So, how about the PPonk?

    Thanks,
    Johnny

  2. #2

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    I have a friend that can start his by hand-propping anytime he needs to. He has a certain process, knows exactly which blade it will fire on every time.

  3. #3
    mvivion's Avatar
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    R-985 is supercharged, so low compression = easy to prop.

    That said a P Ponked 470 should be a piece of cake.

    MTV
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    cubdriver2's Avatar
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    Quote Originally Posted by mvivion View Post
    R-985 is supercharged, so low compression = easy to prop.

    That said a P Ponked 470 should be a piece of cake.

    MTV
    Remember to grab a blade at around 7:00 o clock on a TW airplane and walk your self to the right. If you grab a blade above 9:00 o clock you risk the blade hitting your legs at the bottom of the ark.

    Glenn
    "Optimism is going after Moby Dick in a rowboat and taking the tartar sauce with you!"
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  5. #5

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    With these small Lithium jump packs the only reason to hand prop is starter failure.
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  6. #6
    AKCRUISER's Avatar
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    My brother hand propped his 180 all the time, winter, when he lived in Kotz. Shouldn’t be a problem.


    Sent from my iPhone using SuperCub.Org

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    The only time my Pponk hasn't started was from frosted plugs or battery exhaustion after inadequate pre heat. Hand propping won't fix that. I have no doubt I could start it in good conditions, but I carry a Jump Pack in my day pack so I won't need to.
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    Which one, Stewart?
    Something like this ? https://www.amazon.com/NOCO-GB70-Ult...ump+pack&psc=1
    Quote Originally Posted by stewartb View Post
    The only time my Pponk hasn't started was from frosted plugs or battery exhaustion after inadequate pre heat. Hand propping won't fix that. I have no doubt I could start it in good conditions, but I carry a Jump Pack in my day pack so I won't need to.

  9. #9

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    Earth X Jump Pack. About $125.00. Incredible is an understatement!
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  10. #10
    G44's Avatar
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    R-985 is 7 to 1 compression if I remember correctly.

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    PerryB's Avatar
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    Quote Originally Posted by G44 View Post
    R-985 is 7 to 1 compression if I remember correctly.
    Along with a lot more reciprocating mass. They wake up pretty slowly. The only round motor I ever propped was a 1340 and it was quite an experience. As I passed over the top of compression there was the impulse click and then the prop just sort of accelerated out of my hand in slow(ish) motion.
    After Monday and Tuesday, even the calendar says WTF !
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    cubdriver2's Avatar
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    Quote Originally Posted by PerryB View Post
    Along with a lot more reciprocating mass. They wake up pretty slowly. The only round motor I ever propped was a 1340 and it was quite an experience. As I passed over the top of compression there was the impulse click and then the prop just sort of accelerated out of my hand in slow(ish) motion.

    Alot of engines with mags start much better at a slow rotation speed then fast like a starter spins it. That why some finally kick off when you take your finger off of the starter buttom.

    Glenn
    "Optimism is going after Moby Dick in a rowboat and taking the tartar sauce with you!"
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    S2D's Avatar
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    Quote Originally Posted by cubdriver2 View Post
    Alot of engines with mags start much better at a slow rotation speed then fast like a starter spins it. That why some finally kick off when you take your finger off of the starter buttom.

    Glenn
    I thought that was cause you weren't robbing battery juice going to the coil for the starter
    Never mind, its not worth it !!!

  14. #14
    Hardtailjohn's Avatar
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    Quote Originally Posted by PerryB View Post
    Along with a lot more reciprocating mass. They wake up pretty slowly. The only round motor I ever propped was a 1340 and it was quite an experience. As I passed over the top of compression there was the impulse click and then the prop just sort of accelerated out of my hand in slow(ish) motion.
    985 and 1340 doesn't have an impulse coupling.
    John
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    PerryB's Avatar
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    Maybe I imagined remembering the click. I've been playing with little motors too long. The 1340 prop job was 35 years ago.
    After Monday and Tuesday, even the calendar says WTF !

  16. #16
    180Marty's Avatar
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    About 40 yrs ago, my Dad hand propped his 1340 on his Thrush spray plane and the prop bit him. I had taken the water truck to another airport and waited and waited. Finally he showed up with his left hand bandaged up. The doctor stitched him up and he was good enough the spray. Never did find his wrist watch. He was about 55 yrs old and i don't think he tried that again.

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    Did I mention the Beaver was on straight floats? It always seems safer to pull it when behind the prop, but I'm sure folks have messed up there as well...
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  18. #18
    aktango58's Avatar
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    Should not be a big deal at all.

    Just did the O-540 on my Maule, one blade and she took right off.

    Fuel injected can be a little less fun.
    I don't know where you've been me lad, but I see you won first Prize!

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    I've never seen a Beaver hand started. That couldn't be fun on a chilly morning first flight. I have watched a pilot prop a 206 on floats. That didn't turn out well. For a pilot to solo prop a 206 means from the right float. Getting to the controls took longer than it took for the plane to run into the brushy bank.

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    mvivion's Avatar
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    If it’s possible,I certainly prefer propping from behind. In floatplanes, that’s mandatory unless you have some pretty amazing skills.

    MTV
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    SJ's Avatar
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    I have been unable to get the 3 blade p-ponk to hand prop, I did not have trouble with the 2 - blade 470J, but it has more to do with the prop than anything I suspect.

    sj
    "Often Mistaken, but Never in Doubt"
    ------------------------------------------

  22. #22

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    Agreed. I have never nor likely would ever try hand propping on floats from the front. To clarify, I was trying to convey that I’ve always felt safer swinging the prop from behind, if conditions allow.
    Quote Originally Posted by mvivion View Post
    If it’s possible,I certainly prefer propping from behind. In floatplanes, that’s mandatory unless you have some pretty amazing skills.

    MTV
    Last edited by JohnnyR; 01-11-2018 at 10:08 AM.
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  23. #23

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    Quote Originally Posted by SJ View Post
    I have been unable to get the 3 blade p-ponk to hand prop, I did not have trouble with the 2 - blade 470J, but it has more to do with the prop than anything I suspect.

    sj
    Hmmm.... interesting.
    I would likely put the 3-blade MT on the PPonk engine. If I recall correctly, the blades are the same length in the two blade and the three blade units. If so, should “feel” similar on the swing.

  24. #24
    cubdriver2's Avatar
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    Quote Originally Posted by stewartb View Post
    I've never seen a Beaver hand started. That couldn't be fun on a chilly morning first flight. I have watched a pilot prop a 206 on floats. That didn't turn out well. For a pilot to solo prop a 206 means from the right float. Getting to the controls took longer than it took for the plane to run into the brushy bank.
    It comes down to setting the controls up first so that the plane is sorta going where you want it to after you start it. I do it 10 times a day sometimes (not in a Beaver or 206 but a J4) in some tight spots. Judge the wind and set the rudders for where you want it to go. If you try to rush getting in it takes twice as long. Get back behind the strut and before you start to get in look and see if its going where you want it, if not you have a few choices. Reach in with your hand and adjust the rudders on the right side, or throttle, or shut the mags off if its not listening to you. Then slowly get in. Sometimes you just gota paddle your way clear of hazards.

    Glenn
    "Optimism is going after Moby Dick in a rowboat and taking the tartar sauce with you!"

  25. #25
    Ruffair's Avatar
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    Quote Originally Posted by SJ View Post
    I have been unable to get the 3 blade p-ponk to hand prop, I did not have trouble with the 2 - blade 470J, but it has more to do with the prop than anything I suspect.

    sj
    Was the 2 blade an MT...? Or a Metal prop..?

    I hear a wood composite doesn’t have the mass or momentum to be hand propped. Don’t know. Just hearsay.....

    I’d like to know if some have been able to prop a 180 with a PPonk, with an MT.

    3 blades are much more challenging.
    "...We're fast enough to get there, But slow enough to see..."
    Fron the song "Barometer Soup". By Jimmy Buffett

  26. #26
    aktango58's Avatar
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    Quote Originally Posted by SJ View Post
    I have been unable to get the 3 blade p-ponk to hand prop, I did not have trouble with the 2 - blade 470J, but it has more to do with the prop than anything I suspect.

    sj
    What compression is your plane?
    I don't know where you've been me lad, but I see you won first Prize!

  27. #27
    SJ's Avatar
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    Quote Originally Posted by aktango58 View Post
    What compression is your plane?
    It's not compression, it is more the physics of the 3 blade vs 2 blade.
    "Often Mistaken, but Never in Doubt"
    ------------------------------------------

  28. #28
    aktango58's Avatar
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    Here is the Beaver video: https://www.facebook.com/FrostlinePr...0879544688810/

    As far as running a 206 into the brush hand propping, I preach to tie the plane down! One line from a cleat to the beach would save a lot of grief. One line from the tailwheel to something saves lots of teeth gnashing.

    I know some get away with it for years, but one thing to consider is that if you do it all the time you are much more familiar with how she will react and fire. If you start it once every 5 years by hand you are probably clueless as to exactly where that throttle must be to fire the engine, and a little extra is bad news.

    If I am in a no starter plane, I park with a tail tie in mind. I also carry one long line to get to something that is 40 ' back.
    I don't know where you've been me lad, but I see you won first Prize!
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  29. #29
    cubdriver2's Avatar
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    Quote Originally Posted by SJ View Post
    It's not compression, it is more the physics of the 3 blade vs 2 blade.
    Physics or just plain shorter? Or the head game of you thinking that the blades are closer and the chance of getting wacked is greater? Six cylinder is tougher because the compression stroke feels shorter then a 4 cylinder that most are used to, and they tend not to follow thru with the full stroke because the next cylinder coming on line is changing what you feel.

    Glenn
    "Optimism is going after Moby Dick in a rowboat and taking the tartar sauce with you!"

  30. #30
    Dave Calkins's Avatar
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    I would rather prop a 3 blade 6 cylinder Continental than a 2 blade

    A 3 blade Continental always has a blade at the right location at firing.

    A 2 blade does not. And you have to find the cylinder that fires where yu can throw the prop.

    R985's are childs play to hand prop. Big heavy props and low compression and big magnetos that dont need impulse couplings.

    I ve never been around the boosted mags on 985's in 30 years of Beaver work. Wworth talking about? I could ask some old timers around.

    I prefer to prop from behind. Floats or wheels.

    a 206 or Bananza is no fun. Floats or not.

    A light prop like an MT probably doesnt make it easier. Anyone??

  31. #31
    SJ's Avatar
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    Dave, I find the MT on my cub a pain in the a$$ to prop - but Brian Sutton (guy I bought it from) ran his plane without a working starter for years and hand propped the MT.

    sj
    "Often Mistaken, but Never in Doubt"
    ------------------------------------------

  32. #32
    180Marty's Avatar
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    I've propped my 470K (180 with 29 Bushwheels standing in front)with 2 blade MT a few times and don't find it too bad. I make sure to have a blade up at 10 or 11 oclock and then turn the mags on. Seems I can just get it past compression and sorta let go while backing up and it runs. Even with the starter, I give couple shots of prime, pull through about three blades, get in and one more shot of prime and hit the starter and it usually runs in one or two blades.
    Last edited by 180Marty; 01-11-2018 at 02:40 PM.

  33. #33
    Hardtailjohn's Avatar
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    Quote Originally Posted by JohnnyR View Post
    Did I mention the Beaver was on straight floats? It always seems safer to pull it when behind the prop, but I'm sure folks have messed up there as well...
    I did ours from underneath and behind..me standing in the water. Did that a few times.
    I watched a repo-guy hand prop a P-Navajo one time.... my hat was off to him.
    John

  34. #34

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    My pal has a 3 blade on his, like I say, he has it sorted out. Mostly doesn't do that, but when he does, not a problem.

  35. #35

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    It sounds like a few guys need to sort out their alternator and battery problems!
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  36. #36
    nanook's Avatar
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    The guy holding his hand up missing all the fingers...you say you used to hand prop what!!!

  37. #37
    mvivion's Avatar
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    Quote Originally Posted by stewartb View Post
    It sounds like a few guys need to sort out their alternator and battery problems!
    Really? Try working a trapline around the Arctic Circle, where ten starts, with just a few minutes flight time between stops. Oh, and the temperatures ACTUALLY are well below zero. Do that once and you’ll learn to prop your engine every start.

    Or how about flying an airplane in genuine cold weather with a **** battery.....and you don’t own the plane.

    Or, how about those of us who may not be superbly skilled, and leave the Master on our seaplane, as we’re beaching in a ten knot current, then get distracted while trying to get the Plane secured.

    Etc..... **** happens to some of us, Stewart.

    MTV
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  38. #38

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    Like I said.....

  39. #39
    nanook's Avatar
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    Lithium battery with it's low internal resistance, recharges quickly. Only need 1/2 dozen marten to buy one.
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  40. #40
    Charlie Longley's Avatar
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    Click image for larger version. 

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    Scar on middle finger from propping a 3 bladed 207 back in the day. (30+ years ago) I don’t prop 3 bladed airplanes anymore. The prop comes around too quick!
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