P-51 props

Discussion in 'Aviation' started by grampi, Aug 26, 2013.

  1. grampi

    grampi Member

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    I've noticed there seems to be a couple of different 4 bladers on the D models (and possibly some of the other models too)....some of the props have rounded tips, while others have more squared off tips. What are these prop types called, and were there any performance differences between the two?
     
  2. Airframes

    Airframes Benevolens Magister

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    In 'normal' wartime service, the P-51D was fitted with a Hamilton Standard prop, with the prominent 'cuffs' at the root. This prop was also fitted to the P-51B/C.
    The P-51K was a Dallas-built 'D', fitted with the Aeroproducts prop, without the 'cuffs', and with a different blade shape (the 'K' also had the 'Dallas' canopy, with the taller rear profile, both of these being recognition features of the type.).
    It's generally thought that the 'D' performed slightly better than the 'K', and certainly wartime Mustang pilots I've talked with, both USAAF and RAF, commented that the 'K' seemed to lack a little 'oomph', compared to the 'D', and seemed to be slightly slower in delivering the power via the prop.
    Those Mustangs flying today might be seen with various combinations of props - cuffed and non-cuffed Hamilton Standard, Aeroproducts or maybe Hoffman props, which might explain some of the different blade shapes seen today.
     
  3. stona

    stona Well-Known Member

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    To add to that, you will rarely see cuffed blades today as the cuffs are an expensive addition and offer no benefit for the type of flying warbirds undertake today. They cost enough to maintain and fly as it is!
    Cheers
    Steve
     
  4. GregP

    GregP Well-Known Member

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    One more addition. We are at a cusp in Mustang ownership today. There are no more P-51 props to be had, Hamilton-Standard or Aeroproducts.

    If you're putting one together today, you need to buy two Grumman Albatross 3-blade props and use two blades from each of the props for the opposing blades in your 4-blade, with recountoured blade shapes ... or find someone willing to sell a good prop from a non-flying Mustang. There aren't many of those left lying around.

    Of course, they're also flying Merlin parts today that would have been thrown away 25 years ago, so the props aren't the only critical items these days.
     
  5. pinsog

    pinsog Member

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    Why can't a new prop be built? Why can't a new blade be built from scratch? A blade doesn't seem like a big deal, especially with todays technology. What would be so dard about building a blade from scratch?
     
  6. GregP

    GregP Well-Known Member

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    #6 GregP, Aug 26, 2013
    Last edited: Aug 26, 2013
    The issue is NOT the capability to build a new blade. The issue is liability insurance. NOBODY wants to make new aircraft parts for a 70-year old airplane and have the extended family sue you when the old man cracks it up.

    Take a good hard look at what happened in Reno in 2011.

    Jimmy Leeward crashed his Mustang "The Galloping Ghost," and the family is suing everyone. They're even suing the engine builder! And the engine was running fine right up to impact. So there's no problem making the props ... the problem is finding someone willing to DO it and have it certified in today's legal climate. There isn't exactly a large market and certification would be expensive.

    Not sure if everyone knows it but a stupid Cessna 172 costs $150,000 today. Half of that is liability insurance for Cessna. The planes SHOULD be selling for $40,000 or so. You can buy used 172's in flying shape for $25,000 or less. The rest is just a result of our legal system
     
  7. pinsog

    pinsog Member

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    Attorneys. I should have known. How do you avoid liability issues if you build a prop out of 2 other props? Sounds like it would be a bigger opening for an attorney than just purpose building one from scratch.
     
  8. FLYBOYJ

    FLYBOYJ "THE GREAT GAZOO"
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    #8 FLYBOYJ, Aug 26, 2013
    Last edited: Aug 26, 2013
    HOW DARE YOU CALL A CESSNA 172 STUPID!!!!

    :kamahlitude1: :big14: :kamahlitude1:

    :evil4:
     
  9. pinsog

    pinsog Member

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    FLYBOYJ, it's ok, step back from the computer. GregP didn't mean that the 172 was stupid, but I did hear him say the 182 was better armed, had more armor plate, and could out turn the 172....
     
  10. spicmart

    spicmart Member

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    What where the cuffs good for?
     
  11. Aozora

    Aozora Well-Known Member

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    This one's the Hamilton Standard with cuffs used on the wartime D - note rounded blade tips.

    [​IMG]

    And this one is the Aeroproducts made prop used on the P-51Ks - these had the slightly squared off tips:
    [​IMG]

    Apparently the Aeroproducts props were considered to be less reliable than the Hamilton Standards

    And, just to confuse us, many post-war F-51Ds were retrofitted with a new, Hamilton Standard without cuffs and with square tips

    [​IMG]
     
  12. grampi

    grampi Member

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    The prop on the F-51 is the coolest looking one IMO...I wonder if this one gives better performance than the others?
     
  13. Shortround6

    Shortround6 Well-Known Member

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    It may have but since all props are a compromise just which aspect/s of performance were better is certainly a matter of conjecture without test reports or project specifications.

    Best cruise prop is not the best prop for top speed. Best climb prop is not the best prop for either cruise or top speed. Best speed prop at sea level is not the best speed prop at 20,000ft and so on and so on. Goal may have been to improve climb or cruise without hurting top speed but only those involved in the design may know?
     
  14. GregP

    GregP Well-Known Member

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    #14 GregP, Aug 27, 2013
    Last edited: Aug 27, 2013
    Sorry FlyboyJ,

    I took all but the first two flights for my private license ina C-172 and loved it.

    But there's NO WAY it should cost $150,000! I could love one for udner $40,0000 ...
     
  15. tyrodtom

    tyrodtom Well-Known Member

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    What did the average car cost in 1970, you could get a stripper Mustang (6 cylinder, straight drive, few options) for about $2600, My wife got a more average 70 Mustang, V8, automatic, fastback for $3300. What does a average new Mustang V8 cost right now, around $26-30,000.
    So car prices have increased say about 8x.
    What did a new Cessna 172 cost in 1970 ?
    You can't blame it all on lawyers and liability issues, most of it's just plain old inflation.
     
  16. GregP

    GregP Well-Known Member

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    Actually, MOST of it is product liability insurance for Cessna.
     
  17. tyrodtom

    tyrodtom Well-Known Member

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    I just checked the prices of a 1970 Cessna 172 in 1970, around $13,000, and up, depending on options.
    So the price has increased maybe 11x or 12x, that's not way off from the example of the Mustang .
     
  18. grampi

    grampi Member

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    Why are we discussing Cessna 172s and 6 cylinder Mustangs? I thought we were talking about P-51 props?
     
  19. tyrodtom

    tyrodtom Well-Known Member

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    Read the thread.
    Greg is saying nobody is building new props for Mustangs because of liability issues, and he's saying that's also the reason a new Cessna 172 costs $150,000.

    I'm not disagreeing about the props, but i'm putting forth that a new Cessna 172 cost so much mostly because of inflation, most items sold 40+ years ago, when compared with their modern equivalent have increased about to the same degree in that time.

    It just the usual thread creep.
     
  20. bobbysocks

    bobbysocks Well-Known Member

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    #20 bobbysocks, Aug 28, 2013
    Last edited: Aug 28, 2013

    i agree the prices would have naturally increased significantly due to inflation but it jumped almost over night in the case of aircraft. the aircraft market went crazy in a very short time. back in the late 70s early 80s you could have bought a halfway decent used 150 for for under $5K. with in a couple years the prices doubled or tripled. i remember watching one of those investigative news programs ( 20/20 ..48 hours..etc ) and the story was the general aviation and liability. the owner of a company that manufacturered magnetos was being interviewed. he sighted he had to scale back operations and lay off staff due to law suits and lawyer costs. he was currently had just paid a settlement to someone for a case he would have won. the pilot ran out of fuel and crashed. even though it was the pilots error...and the magnetos had nothing to do with the crash...they sued that company too. it was cheaper for the company to settle for a large amount than it was to pay the lawyers to litigate for several years. its the same thing in healthcare. the prices on some items like catheter tubes is inflated dramatically as they are items always mentioned in law suits. in the case of aviation it is one of the reasons ultralight and e-lsa aircraft were created.
     
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