The Pou-du-Ciel Grunberg U/L HM293

Discussion in 'Wood Construction' started by rbrochey, Mar 29, 2017.

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  1. Mar 31, 2017 #21

    Pops

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    Wood is Good.
     
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  2. Mar 31, 2017 #22

    FritzW

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    A compass??? ...you guys up north have all the fancy stuff. Give me a gas gauge and a 1974 Texaco road map ;)

    "...all I ask is a tall ship and a star to steer her by"
    John Masefield


    Question for Flea guru's: do all of the modern Flea variants have the same geometry? ie. the same ratio of gap to chord, same stagger, same airfoil etc.
     
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  3. Mar 31, 2017 #23

    cluttonfred

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    Short answer is no. Original Mignet designs still being built (mostly HM.293 but also HM.14/360, HM.360, HM.380) have the typical Mignet platform with less stagger and a smaller rear wing. Ditto the formerly factory-built Balerit and Corduouan microlights. Various Croses designs typically have narrower chord, more stagger, more closely matched wing areas. Both approaches seem to work just fine.
     
  4. Mar 31, 2017 #24

    Victor Bravo

    Victor Bravo

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    Matthew and/or Koen, is there any significant difference in the performance or handling of the "older style " Flea (HM.14/360 etc.) than the later style (HM.293)? I'm guessing that the '14 style open cockpit fuselage makes about the same drag as the '293 style open cockpit fuselage. But the extended landing gear of the later airplanes has to make some amount more drag than the early airplane with the axle right at the bottom of the fuselage. This creates a difference in the height of the thrust line, and all manner of other issues that snowball off of that.

    So this led me to wonder if the early style airplanes are faster or slower than the later style, or if the thrust line being low or high makes one version more or less delightful to fly than the other.

    If I ever did want to build a true Flea I would prefer to keep the original look, even though I would of course incorporate the aerodynamic advances that are mandatory.
     
  5. Mar 31, 2017 #25

    cluttonfred

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    I think the HM.293 would offer better performance than an HM.14 variant, though I don't deny that the original Pou-du-Ciel style has a certain irrepressible charm. I am also fond of the HM.18, Mignet's first fully-enclosed Pou-du-Ciel, sadly sidetracked by the problems with the early HM.14 that it did not share.

    IMG_0417.JPG IMG_0418.JPG IMG_0419.JPG
     
  6. Mar 31, 2017 #26

    Victor Bravo

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    Looking through the HM 293 images I ran across this one... the look on the pilot's face says it all :)

    [​IMG]

    Flying Flea Rope Start.jpg
     
  7. Apr 1, 2017 #27

    Tiger Tim

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    Those tailwheel 293s are just so... charming. If only I didn't have all my other projects that I have no time for...
     
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  8. Apr 1, 2017 #28

    Dana

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    There was a beautifully built Pou with a BMW motorcycle engine at an airport near me here in CT. Unfortunately, it was destroyed after an engine failure on its second flight.

    Dana
     
  9. Apr 1, 2017 #29

    cluttonfred

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    That's really terrible, and the pilot was seriously injured, but I am glad he seems to be recovering. It's a great site with lots of nice touches. See the great little walkaround video clip at the bottom of this page: http://www.flying-flea.org/final-approach--bringing-it-all-together.html The entry below is taken from the builder/pilot's last page marked "The End": http://www.flying-flea.org/the-end.html

     
  10. Apr 1, 2017 #30

    Tiger Tim

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    "Turning took a little practice to get the roll angle just right."

    What? Could someone with Flea experience elaborate on this?
     
  11. Apr 1, 2017 #31

    cluttonfred

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    Since most Mignet-type tandems use the variable incidence front wing for pitch and an aerodynamically balanced, all-moving rudder for yaw (which also induces roll), the controls are very powerful and usually pretty light to operate. Combined with the relatively short fuselage the sensitivity of the controls takes some getting used to. It sounds like he was simply overcontrolling. There is also the issue of getting used to the rudder-only yaw/roll so you are following along with the dihedral effect instead of fighting it.
     
    Last edited: Apr 1, 2017
  12. Apr 1, 2017 #32

    skier

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    Wow, that's really sad to hear. I had been following his build and had talked with him about to meeting him at the airport sometime. It's been a few months since the accident. I hope he's continuing on the path to recovery.
     
  13. Apr 1, 2017 #33

    Dana

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    Yes, it's a shame. I met him when I flew my Fisher over to Waterbury (great little grass airport, I wish it was close to my home) and saw his Pou in the hangar along with another Fokker Triplane. At that point he hadn't flown it yet. Then I saw it again at the Simsbury fly-in last year; I assumed he had flown it there but it looks like the first flight was after that so I guess he must have trailered it to Simsbury. Beautiful workmanship, with the funkiness you'd want and expect to see on a Pou.

    Dana
     
  14. Apr 4, 2017 #34

    FritzW

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    So on Flea's, do you have to hold back pressure on the stick all the time? If so, what happens if you let go of the stick?
     
  15. Apr 4, 2017 #35

    cluttonfred

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    It depends on the rigging and the airfoil used, it is certainly possible to use a fixed tab to dial out that pressure at cruising speed. I think it is safer and better to do that so that when you let go of the stick...nothing happens.
     
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  16. Apr 4, 2017 #36

    rbrochey

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    How and where would that tab be attached?
     
  17. Apr 4, 2017 #37

    cluttonfred

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    I have seen bungees on the stick but I think I would use one or two tabs on the trailing edge of the front wing.
     
  18. Apr 4, 2017 #38

    rbrochey

    rbrochey

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    Thanks! That seems a good plan! :)
     
  19. Apr 4, 2017 #39

    FritzW

    FritzW

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    For some reason I had in in my head that the Grunberg version of the HM-293 had a different airfoil and didn't need back pressure on the stick. ...it's tough to study a design when 90% of the information is in French :gig:

    I think a regular 'ol cable and spring trim system would be pretty simple to do.
     
  20. Apr 4, 2017 #40

    Tiger Tim

    Tiger Tim

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    I'd be inclined to go with a fixed trim tab on the forward wing so that if something comes apart in the controls it won't tend to dive.

    As for the French plans, it would be nice if someone went through them and redid the notes en anglais.
     

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