I have been biten again by the tsetse fly

Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by berridos, Nov 19, 2019.

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  1. Nov 19, 2019 #1

    berridos

    berridos

    berridos

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    After putting on hold the construction of my conventional design (its hanging from the roof in my workshop) i feel again called by the project i should have chosen from the beginning. I am talking about the Verhees Delta. I think i will buy myself the plans for christmas and redesign it in cad.
    The beauty lies in the simplicity of construction in case composites are used and its cleaness.
    Whats your opinion on the new 2 seater version? Dont you think it has lost the sexappeal? Aerodynamically it has lost his effciency with such a wide cabin upper body.

    Regarding the one seater, it used significant reflex of ailerons. Would anybody suggest alternatives to reflex that acchieve the same effect? Would wing twist be equivalent?
    Anybody could comment the aerodynamic side effect of the cabin transitioning into the fin starting at the thickest section of the wing profile. Any suggestion to improve the bird aerodynamically?
    Could you think of some device to reduce landing speed (leading edge flaps?) effective on deltas 2 seater.jpg Delta-1-fotoshoot.jpg ?
    I will redesign it adapted to composites.
     
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  2. Nov 19, 2019 #2

    wanttobuild

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    I am glad to see this aircraft is going composite.
    It is a very good time for experimentation!
    Carbon and Cad, what a combination.
    I wish you all the best and I hope you make a ton of money selling plans.
    Ben
     
  3. Nov 19, 2019 #3

    Aesquire

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    Re: twist.
    Flex wing hang gliders & weight shift wings use considerable twist compared to a "normal" plane. Partly for pitch stability, and a Lot to reduce tip stall. The gliders are often in minimum radius turns near stall in turbulent air. The loss of spam efficiency is a compromise.

    On the Delta the advantage would be tiny, and the loss of spam efficiency large.

    Consider the elevons the tail and ignore their area as lift producing.

    Even with a zero pitching moment airfoil, you need the reflex to balance the Center of gravity ahead of the Center of lift in a speed variable manner to be stable.
     
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  4. Nov 19, 2019 #4

    fly2kads

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    I know this is a typo or an "autocorrect fail," but I am still amused by the idea of "spam efficiency." Cue the Monty Python skit! Sorry, carry on....
     
  5. Nov 19, 2019 #5

    Victor Bravo

    Victor Bravo

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    No one expects the HBA Inquisition !
     
  6. Nov 19, 2019 #6

    cheapracer

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    We're just here for the 5 minute argument.
     
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  7. Nov 19, 2019 #7

    cheapracer

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    I love Deltas, love the Verhees, but I can't stand the nose high attitude of it in flight, and the 2 seater looks even worse.

    Other Deltas don't fly quite so nose high, what's causing it?
     
  8. Nov 19, 2019 #8

    Jay Kempf

    Jay Kempf

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    Velocity!
     
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  9. Nov 19, 2019 #9

    Victor Bravo

    Victor Bravo

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    It's pretty convenient to lay out a delta with a symmetrical or nearly symmetrical airfoil. But if you are only going 70-120 mph... :)
     
  10. Nov 19, 2019 #10

    narfi

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    That is a pretty subjective term........ Only you can answer it for yourself :p
    For me the two seater 'looks' better, but I like the facetmobile better than both.
    I think a 4/5 place composite facetmobile would be interesting.
     
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  11. Nov 19, 2019 #11

    cheapracer

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    Really? I think the Facetmobile is rather ugly, far too much bulky 'folded paper' look about the rear half.

    The blue 2 seater above looks pretty good other than the 'nose high' I mentioned. I like the clear separation of the cockpit compared to the Facetmobile.
     
  12. Nov 19, 2019 #12

    Aerowerx

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    Remember the wing is the plane!

    On a conventional aircraft design, the wing is typically at some angle to the fuselage in order to get the required AoA and resultant lift, keeping the fuselage level. Most airfoils in common use do not give enough lift at 0.0 AoA.

    So for the deltas being mentioned here, of course they look nose high. How can they be anything else, and still get the required AoA?
     
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  13. Nov 19, 2019 #13

    narfi

    narfi

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    sub·jec·tive
    /səbˈjektiv/

    adjective
    1. 1.
      based on or influenced by personal feelings, tastes, or opinions.
     
  14. Nov 19, 2019 #14

    Deuelly

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    I actually just spent two years laying the Verhees Delta out in composite. Its amazing the minimal parts count you end up with. I did change the canopy and fin layout a bit.

    The outer wing panels do have twist. From the root of the outer panels to the tip there is 1.5° of twist(washout).

    I don't need my original plans anymore and was actually just thinking of getting rid of them.

    Brandon
     
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  15. Nov 19, 2019 #15

    berridos

    berridos

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    While i really liked the weber mpr850 engine, the d-motor l-26 (liquid cooled) would fit much better in the leading edge nose (beeing a very flat design), having much more power than the subaru or vw the original design proposes, having on top much less weight. The leading edge radiator could allow for extra thrust guiding the cooling and exhaust gases together to the rear of the aircraft in a tunnel thru the spar at the side of the cockpit.
    The original design has a a cruise speed of 138mph. The new engine installation, much cleaner, with variable prop and a smooth composite design could be expected to reach realistically a cruise of 150mph.
    On top i could ask peter ( raptor design ) on how to add nitro injection to reach 170mph)))
    Stall is 53mph. I read the design is very resistant against wind shear. The airport i have in mind has tons of wind.
    Obviously, the verhees would be a dream if it was a pusher, but that would be a blank paper design. Landing gear would have nice fairings.
     
    Last edited: Nov 19, 2019
  16. Nov 19, 2019 #16

    berridos

    berridos

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    Deuelly, would you be so kind to sell me the plans? Do they state the wing profile and overall contain exhaustive information?
    The partcount issue is on top of my mind.
     
  17. Nov 19, 2019 #17

    Doggzilla

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    It’s CG is so far forward. It’s like 25% from the front, not 25% ahead of the center of lift.
     
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  18. Nov 19, 2019 #18

    proppastie

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    I have to wonder how that handles?.....Talk about "short coupled"
     
  19. Nov 19, 2019 #19

    Aerowerx

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    Do you mean 25% of the mean chord? Or of the root chord?

    In either case, 25% from the front doesn't seem unreasonable, if the center of lift is 30-40% from the front.
     
  20. Nov 20, 2019 #20

    Deuelly

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    On my drawings the aft CG limit is 42.6% back from the front.

    I could possibly do that. You're not in the states are you. I'll send you a PM tomorrow.
     

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