gregwatts Posted January 28, 2012 Report Posted January 28, 2012 Quote: sleepingsquirrel I'm glad someone asked those questions. I was also wondering if I should be making an equal number of diving turns turns to the right to compensate the bending moment and uneven bearing wear on the crank shaft front bearing caused by correction for P factor when I climb out? Quote
lieutenantdanbr Posted January 28, 2012 Report Posted January 28, 2012 I aksed the prop shop at Forth Worth about push/pull on the prop TIP. His reply was if you can bend the prop pushing and pulling by hand, you have just become the world's strongest person. AND even then, the prop won't move. BTW, that shop rebuilt the blades on FIFI, maybe the only flying B29. It is also a great place to visit, really old school machine work. Now, if you use a machine and the plane is chocked, even then maybe. Quote
orangemtl Posted January 28, 2012 Report Posted January 28, 2012 This really seems like an "It Depends" sort of issue. Yanking on the blades at the distal tips, or pushing on same to initiate a move seems like a uniquely stupid idea. But, if you are using a towbar as the primary mover, I'm hard pressed to imagine that my bristling, muscle bound 163 pounds (at 51) is going to crush the nosecone into the engine by using it as a secondary guide. Pulling on the blade roots? Perhaps not ideal, but I suspect not particularly detrimental, so long as it is secondary to hauling the plane via towbar. If the engine/prop was that delicate, maybe we should pack our planes in piles of fluffy pillows in the hangar, so sparrows don't sit on the roof and crush them. Quote
N601RX Posted January 28, 2012 Report Posted January 28, 2012 Quote: allsmiles You need certain prerequisites! Quote
Bartman Posted January 28, 2012 Report Posted January 28, 2012 I push/pull on the prop at the base of the blade. However do not push on the spinner. You can damage the spinner and possibly the hub it attaches to. Don't ask me how i know this. Quote
jetdriven Posted January 28, 2012 Report Posted January 28, 2012 Quote: allsmiles Do give us a proper analysis of the physics involved... please! Quote
N33GG Posted January 28, 2012 Report Posted January 28, 2012 Quote: lieutenantdanbr I aksed the prop shop at Forth Worth about push/pull on the prop TIP. His reply was if you can bend the prop pushing and pulling by hand, you have just become the world's strongest person. AND even then, the prop won't move. BTW, that shop rebuilt the blades on FIFI, maybe the only flying B29. It is also a great place to visit, really old school machine work. Now, if you use a machine and the plane is chocked, even then maybe. Quote
orangemtl Posted January 28, 2012 Report Posted January 28, 2012 Well, I've learned three things in this string: 1. Pushing on the blade root: Probably fine. Better than pushing on the spinner, which I will follow. 2. People get needlessly wound up and sometimes very snippy in semi-anonymous blog strings, about very narrow issues. 3. I know less physics than many people: but, probably just enough to get by. Thanks. Quote
maniago Posted January 28, 2012 Report Posted January 28, 2012 Quote: jetdriven Do give us a proper analysis of the physics involved... please! Quote
201er Posted January 28, 2012 Author Report Posted January 28, 2012 Quote: N6719N I doubt I have hurt any aircraft or engines by using the prop. Spinners, cowls, wings and horizontal stabilizers are strictly off limits. Quote
201er Posted January 28, 2012 Author Report Posted January 28, 2012 Quote: maniago @Allsmiles: Thanks for your post. I'm not into flaming people, so I'm happy to be let this one go. Sure would like to drink a beer with you and do some hangar flying. I think we'd have a dandy time talking with our hands, drawing diagrams, and telling war stories while shooting our watch...."No shit, there I was...." "No way! There is no way you can do that" "Did too!"... What a great place this is for discussion! Quote
N33GG Posted January 28, 2012 Report Posted January 28, 2012 Quote: 201er I completely understand not pushing on all of the above except for wings, What's wrong with having an assistant (when you do have someone around) push on the leading edge of the wing near the root where the rivets indicate a rib? Trailing edges, stabilizers, etc are quite obviously off limits. I get furious when people try to use my horizontal stabilizer as a writing desk. Quote
201er Posted January 28, 2012 Author Report Posted January 28, 2012 Oh. Well I'm just asking about our Mooneys? I don't touch anyone else's airplanes unless directed. Quote
maniago Posted January 28, 2012 Report Posted January 28, 2012 Quote: 201er You could. We're having a New Jersey Mooney Pilots Fly in at KVAY tomorrow from 11-2. He's based there and said he'll drop in. He can have the beer but you probably can't Quote
N33GG Posted January 28, 2012 Report Posted January 28, 2012 Mooney wings are pretty darn tough. Not likely to damage a Mooney wing by pushing on the leading edge. Sorry if I confused anybody out there. Quote
kerry Posted January 28, 2012 Report Posted January 28, 2012 I have m20a. In my mooney maintence manual it says to tie a rope or strap around the prop and connect to a hoist (I use a cherry picker) to lift the plane up for a gear retraction. This comes from mooney. I would imagine this would put more adverse forces on a prop vs. using it to push or pull the plane. Quote
PTK Posted January 28, 2012 Report Posted January 28, 2012 Quote: N601RX And you have these prerequisites? I don't remember any pre dental majors in any of my physics or engineering classes. They just had to take the "Mickey Mouse" non Cal based physics. Quote
alex Posted January 28, 2012 Report Posted January 28, 2012 Quote: allsmiles You need certain prerequisites! Quote
DonMuncy Posted January 28, 2012 Report Posted January 28, 2012 To those who erroneously state that Mooney advocates against pushing/pulling on the prop; My K model POH says; "When no towbar is available, or when assistance in moving the aircraft is required, push by hand: (1) on the wing leading edges, and (2) on the inboard portion of propeller blades adjacent to the propeller hub." Quote
jetdriven Posted January 28, 2012 Report Posted January 28, 2012 I asked my IA about this last time it flared up. His reply was they both have been pushing airplanes around by the prop for 50 years. Never had a problem. He had a red-tagged Continental C-65 crank on the bench. You could lever a Peterbilt off the pavment with it. It looked like a crank out of a 454 Chevy. Quote
N601RX Posted January 28, 2012 Report Posted January 28, 2012 Quote: allsmiles And you have these prerequisites? I don't remember any pre dental majors in any of my physics or engineering classes. They just had to take the "Mickey Mouse" non Cal based physics. Quote
sleepingsquirrel Posted January 29, 2012 Report Posted January 29, 2012 Quote: N6719N Mooney wings are pretty darn tough. Not likely to damage a Mooney wing by pushing on the leading edge. Sorry if I confused anybody out there. Quote
Emmet Posted January 29, 2012 Report Posted January 29, 2012 As being an engineer for over 20 years I wonder how allsmiles will be able to do a stress calculation without having the specifcations and design data for the critical components involved. Looks like sound engineering to me ... maybe it's better to stay with Biochem... "I hope we can agree that a static force on the prop perpendicular to its direction of rotation, such as applied when attempting to move the airplane on the ground, is very different than the dynamic loads parallel to its direction of rotation, such as when the engine and prop are rotating in flight" Sorry, but all that comes to my mind is - what a complete bullshit ... Engineering is a science of facts and numbers - not opinions ! Just my 5 cents Quote
pjsny78 Posted January 29, 2012 Report Posted January 29, 2012 We all at the nj mooney club all owe dr smiles a big thank you. He paid for everyone's lunch today. Hes not that bad of a guy. Thanks again dr. Smiles.... Quote
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