Tandem wing for high efficiency? Case Proteus

Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by karoliina.t.salminen, Aug 13, 2011.

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1. Sep 20, 2011

Hot Wings

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3. Jun 5, 2013

erdal

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Hello,
Not sure if anyone is still checking this post, but I have a question:
When we use tandem wing, lift generated by canard contributes to total lift force. But in conventional configuration tail force is downward, hence we loose that much amount of force from wing lift.
Total Lift = Lift_Wing + Lift_Canard for canard configuration
Total Lift = Lift_Wing - Lift_tail for tail configuration
Has anyone ever considered this loss of lift force and how significant it could be? İt looks like canard has a relative advantage in this regard.

4. Jun 5, 2013

timberwolf8199

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Same goes for a lifting tail and is part of the reason for the higher efficiency associated with tail draggers.

5. Jun 5, 2013

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If you look at them isolated; yes. But the down wash of the canard is hitting the wing, resulting in a significant penalty. With a conventional plane on the other hand, the down wash of the wing hits the tail which is beneficiary.

6. Jun 5, 2013

bmcj

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Yes, it has been discussed and debated in great detail here. Canards have the advantage you mention, but some would argue that the net effect is negative, saying that the trim drag of the canard is higher than the trim drag of a tail and that the conventional configuration allows the designer to optimize the airflow for the wing.

One thing for certain is that you will have a higher landing speed for a canard (all other things being equal) because you will not be able to use big flaps on the wing and you can't bring the wing up to the stall AOA (i.e. - maximum lift coefficient).

7. Jun 5, 2013

captarmour

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with a close coupled canard you get beneficial interference and 'slot' effect that increases lift much more than just the increased area. also the local flow on the leading edge of the wing has a vertical component which tilts the canard's lift vector forward creating some 'thrust'. the Saab delta canards have STOL capabilities and fly as fast as mach 2.

although this is a very lightweight model, when compared to other models it seems to be very good.

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"The aim was to produce a robust aircraft with good short-runway performance that could be operated from numerous specially prepared roads and highways to reduce the vulnerability to attack in the event of war.[SUP][2][/SUP] Other requirements includedsupersonic ability at low level, Mach 2 performance at altitude, and the ability to make short landings at low angles of attack (to avoid damaging improvised runways)."
Saab 37 Viggen - Wikipedia, the free encyclopedia

8. Aug 29, 2014

sigrana

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His name s Darrel, (not Darrol)

9. Aug 29, 2014

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