Decalage angle

Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by Eugene, May 29, 2017.

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  1. Jun 13, 2019 #1041

    poormansairforce

    poormansairforce

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    Mike Arnold talks about this pressure recovery on his AR-5 and not losing airspeed in a turn.
     
  2. Jun 14, 2019 #1042

    Eugene

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  3. Jun 14, 2019 #1043

    Eugene

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  4. Jun 14, 2019 #1044

    Eugene

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    EED301BC-C986-4F2A-AD7D-A79C4149C3C1.jpeg

    Hopefully I got it right this time
     
  5. Jun 14, 2019 #1045

    Doggzilla

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    Looks good so far. How are you considering constructing it?

    I would probably cover the aircraft in plastic and use foam to sculpt the new shape, then create a cast by placing plastic on it and laying more foam to make a negative/cast.

    But that is not my area of expertise and Im sure some of the other members can give more detailed and accurate instructions, quite a few of them have made entire aircraft using foam and casts before.
     
  6. Jun 14, 2019 #1046

    Doggzilla

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    Yes, that looks much better than my sleep deprived drawings in MS Paint.

    With a little practice you should easily be able to create a cowling. The real question is how you want to attach it. Forward hinges? Forward sliding rails like a cabinet? Or sideways (but this can interfere with access to the other side).
     
  7. Jun 14, 2019 #1047

    Eugene

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    For some reason building was never problem for me, but to find correct shape is not easy at all.

    From what I understand every part of your airplane does some kind of work. Some working for you, but some agains you.

    No matter how hard I try bottom of my fuselage still will have 8-10° angle in level flight
     
  8. Jun 15, 2019 #1048

    Eugene

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  9. Jun 15, 2019 #1049

    Eugene

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    Screen Shot 2019-06-14 at 21.30.52.png

    Looks like they doing the same thing by filling empty pockets behind the wing. So ,I must be moving in right direction.
     
  10. Jun 15, 2019 #1050

    proppastie

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  11. Jun 16, 2019 #1051

    AdvenJack

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    Last edited: Jun 16, 2019
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  12. Jun 16, 2019 #1052

    plncraze

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    Robert Cumberford did a report on this plane in a 1975 Air Progress and said the students who built it were underwhelmed by its performance.
     
  13. Jun 16, 2019 #1053

    Doggzilla

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    Its 23% faster than the Cessna 152 it took the engine from, which is pretty good.

    Its roughly like comparing a Mooney M20 to a Cessna 172. Its a very impressive increase in performance, but without suffering the limitations of the Mooney.

    I would call that quite successful.
     
  14. Jun 16, 2019 #1054

    plncraze

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    IIRC the students who built it had expected even better performance than they got and it was overweight. I wonder if a propeller designed to work in the airflow of the tail would improve it.
     
  15. Jun 16, 2019 #1055

    BBerson

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  16. Jun 16, 2019 #1056

    Eugene

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    fullsizeoutput_173d.jpeg


    I was told this morning that this is correct explanation, but at wrong speed. They think, that this effect is only big enough above 200 km/hr to worry about. Engine cowling at speeds below 100 mph = 160 km/hr on engine sitting on backside of the wing and behind BRS will give you at best 3 mph. It will improve airflow to the prop at 20-30%. That area on your prop not doing much anyway.

    Searay designer tell me same thing - "waste of time and effort with no speed increasing at all"
     
  17. Jun 16, 2019 #1057

    Eugene

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    Anybody know what kind of airplane this is? I can't find it anymore.

    Screen Shot 2019-06-16 at 08.52.48.png
     
  18. Jun 16, 2019 #1058

    plncraze

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    It looks like a modified Piaggio Avanti. It looks like they fattened out the fuselage to cover the wing out to the nacelles. If you can picture the airflow in front of the props you are probably as baffled as I am to why they did this unless they are just modeling the forward fuselage.
     
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  19. Jun 16, 2019 #1059

    Eugene

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    Its not a canard and only one engine
     
  20. Jun 16, 2019 #1060

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