Three blades MT prop for Pitts S2A ?

Discussion in 'Aerobatics Talk' started by Mael, Aug 5, 2014.

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  1. Aug 5, 2014 #1

    Mael

    Mael

    Mael

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    Hi there,

    Last friday, I have found three nicks on one of the Hartzell blades of my Pitts S2A... Stones hiden on a grass taxiway probably did those damages.

    My mechanic had a look to the prop and checked on the Hartzell documentation and it is good enough to keep flying under surveillance.

    Anyway, I don ´t really feel good in doing advanced and gyroscopic aerobatics ( yes, S2A can do that...) with a damaged prop.

    So I was thinking about changing it for a light 3 blades MT.
    I am looking for feedbacks from people who did this before... Every comment is welcome.

    Mael.


    Envoyé de mon iPad à l'aide de Biplane Forum
     
  2. Aug 5, 2014 #2

    jerr888

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    Don't believe the 3 blade is any lighter?
     
  3. Aug 5, 2014 #3

    Eagle-Mike

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    Have a MTV9 on my Eagle. 31 ibs prop + 4 ibs spinner. No complaints so far with the installation. But you should choose the pressure servo option. Goes to coarse pitch quite fast if oil pressure drops during acro.
     
  4. Aug 5, 2014 #4

    Eagle-Mike

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    I recently had a discussion with a guy who flew formation with another super Decathlon. His Decathlon with a MTV9 and the other with the Hartzell 2-blade. The 2-blade was considerably faster in cruise with the same power setting than the MTV9. No information on differences in aerobatic performance.
     
  5. Aug 5, 2014 #5

    PittsDriver68

    PittsDriver68

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    The 2 blade Hartzell and the STC-ed 3 blade MT weigh the same (about 55lbs). The difference is where the weight is. The center of mass for the MT is much closer to the hub so the stress on the hub and crank are much lower. Snaps and gyroscopics are different as a result.

    Unfortunately, the 2 blade MT is not STC-ed for the S-2A here in the US.

    A neighbor who put an MT on his S-2A loved it. But he spent north of $11K for the upgrade. I do not know what he sold his Hartzell for, but that probably took some of the sting out of the cost.

    I have been advised against gyroscopic figures in my S-2A with the aluminum Hartzell prop, even though the prop is only 50 hours out of overhaul and a new hub. Something about crankshaft failures.

    Best of luck,

    Wes
     
  6. Aug 5, 2014 #6

    aero_jan

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    I've done most of my Pitts flying on an S-2A with the Hartzell prop. However, last year I trained a couple of days in Alan Cassidy's S-2A which is fitted with the MTV-9. I can't say I noticed a big difference in performance between the two.

    You could try to contact Alan through his website and ask for his experience as an owner. He is a very experienced Pitts instructor and aerobatic competition pilot in the UK.

    http://freestyleaviation.co.uk/Freestyle/Aeroplanes/pittss2a.htm
     
  7. Aug 6, 2014 #7

    jerr888

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    Anybody know of a failure of a S2A crankshaft flange with the Hartzell??
    Anybody have an instance?
    Also, later crank flanges are thicker and not with lightening holes, so that adds a little comfort.
    Recent Ultimate lighweight "prop" failure (may have thrown a blade), caused loss of aircraft, pilot chuted out OK!
    However, these planes are getting old!
    There's no free lunch!!!!!
     
  8. Aug 6, 2014 #8

    race38

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    Not a biplane, but Kirk Wicker lost his Hartzell from the CAP 21 he was flying at the College Park Airshow in the late '90s. Broke behind the seal inside the case. Not pretty. There is a video of it on the web.
     
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  9. Aug 6, 2014 #9

    jerr888

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    Yeah:
    Kirk did it so effortlessly, you'd think he practiced no prop landings. Great video!
    There have been instances like this, but I haven't heard of one in an S2A. S1T (Tom Jones) yes!
     
  10. Aug 6, 2014 #10

    race38

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    I watched the whole thing. I had just convinced my ex to let me buy half of that airplane. Fortuitous?
     
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  11. Aug 7, 2014 #11

    Mael

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    Thanks,

    I will contact him and ask for a feedback. And why not going to his plane to try his S2A. I think that would be the best thing to do.
     
  12. Aug 7, 2014 #12

    aero_jan

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    Yes, it makes sense to try the MT before spending a lot of money on a new propeller. From what I remember the main benefits are that it runs smoother and you'd loose the rpm restriction on the Hartzell. Alan is a very friendly and knowledgeable chap. You'll have a good time and White Waltham is a nice (but bumpy) airfield.

    I don't know whether your Pitts is certified or what the rules in France are but the Whirlwind 200C might also be a good match for the S-2A. From what I've read the performance might be better than the MTV-9 and it's a bit lighter as well.

    http://www.whirlwindaviation.com/props/200400series.asp
     
  13. Aug 7, 2014 #13

    Carlyle

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    I have a story for you. PM me.
     
  14. Aug 7, 2014 #14

    grassroots

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    Smoothness is nice, but it's not a a big motivating factor for most. As has already been mentioned, it's mostly about crank stress reduction. There are also significantly reduced gyroscopic and torque effects, which work against you during certain aerobatic figures. On my S-1S, the light prop also made it lighter and nicer feeling in pitch. 3-blade also makes less noise than a 2-blade at the same RPM, if you are flying in a noise sensitive area.
     
  15. Aug 7, 2014 #15

    aero_jan

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    I agree with that. I wrote about the things I noticed most while flying the plane.
     
  16. Aug 16, 2014 #16

    Mael

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    I have had some nice e mails from Alan Cassidy in UK. He flies a MTV9 on regular basis and he is happy with it. Advantages are mostly about reducing stress on the engine and reducing noise level and vibrations.

    Sharing experience is always good.
    Thanks Alan and thanks Biplane Forum.
     
  17. Oct 31, 2014 #17

    Mael

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    Hi guys,

    I am about to order the MTV9 prop for my S2A. I need to check that the prop governor fitted on the back of my AEIO360 A1A is okay for that MT prop. Unfortunately, that governor is in some kind of box inside the firewall and I can ´t see any model type or part number...

    Does anybody knows what that governor might be ?

    Thanks.
     
  18. Oct 31, 2014 #18

    PittsDriver68

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    Your big black bulky governor is a Hartzell F-6.

    I am under the impression that the STC-ed MT comes with its own governor.

    I am replacing the ancient and heavy Hartzell F-6 with a new, lighter, PCU-5000. My local Red Bull Air Race veteran engine rebuilder tells me that the PCU does very well at high G and accellerating out of turns.

    Best of luck,

    Wes
     
  19. Oct 31, 2014 #19

    Gonzo

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    I replaced my Hartzell with an MTV 9 3 blade prop, I put both on my doctor's detecto scale and the Hartzell is 5 lbs lighter than the MT. The
    stock Pitts S2A spinner is 15 oz heavier than the MT spinner assembly. In
    order to balance out I put a PLane Power alternator on which is 5 lbs lighter than the original Pitts alternator. Now performance, quiter, smoother, climbs harder, but slower in cruise, well really is that important it is a Pitts not a Lancair or Glassair. My whole package w/spinner was $13,500, fob PA from FL. I sold the Hartzell for $4000.
    Also it looks cool!
     
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  20. Nov 2, 2014 #20

    Mael

    Mael

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    Wes, you are right. I eventually found a number on the side of the governor. It says F-6-31.

    Gonzo, how slower do you think your airplane is with that new MT Prop ?

    Other question, what is supposed to happen in case of oil pressure drop or governor failure ? Are both propeller going to high RPM ?

    It is always nice to read from you.

    Mael.
     

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