WIX Archives

Thanks Christer and Richard !

Posted by MickM on Fri Oct 05, 2001 04:34:00 PM

In reply top Now I´m in it up to my neck!? posted by Christer on Fri Oct 05, 2001 11:35:52 AM

That's some good and interesting stuff, thanks very much!

Cheers
Mick




: Mick,
:
: again from what I?ve read, the stalling characteristics of
: the Corsair is due to the flap in fully extended landing
: position disturb the airflow over the horisontal stabilize
: r. Especially under cross wind conditions pilots often cho
: ose to reduce the flap setting. This prompts a higher appr
: oach speed with higher margins but, in consequence longer
: landing distance.
:
: I?ve also read a little about the Bearcat, the articulated
: landing gear legs were neccesary to fit them into the win
: g inboard of the cannons.
: There were several means of achieving this, e.g. the twent
: y-series Spitfires, haveing a larger diameter propeller th
: an the earlier Griffon-Spits, had a device which compresse
: d the oleos when retracting the landing gear.
:
: Regarding the Stuka, I haven?t got a clue, never studied i
: t.
:
: To the subtelties of aerodynamics, well, I?m a keen glider
: pilot and the design of gliders focus on reducing drag be
: cause it?s simply a drag!
: One of the most renowned designers is a personal friend of
: mine (have flown his designs for years) and through him I
: ?m acquainted with the work of a professor of aerodynamics
: at the University of Delft who is into the airfoil resear
: ch.
:
: I won?t dig too deep into this but generally the drag-coef
: ficient can be subdivided into three parts:
: 1) The frontal area of the airframe (what "hits" the airfl
: ow) and the wet area of the airframe (what the airflow has
: to travel along). These two together is called the fricti
: on drag or zero drag (when the airfoil is generating zero
: lift).
: 2) The interference drag is caused by the airflow around t
: he wing, the horisontal stabilizer and the fin interfering
: with the airflow around the fuselage.
: 3) Induced drag is the drag from all lift producing member
: s. The main contributor is the wing but also the stabilizo
: r and fin generate drag. The higher the lift-coefficient,
: the higher the drag-coefficient.
: Lift produced by an airfoil is proportional to the airspee
: d and angle of attac. To maintain level flight (at constan
: t altitude) the angle of attac is high at low speed, using
: a high lift-coefficient. The angle of attac is low at hig
: h speed using a low lift-coefficient.
: If you then start turning the angle of attac gets dramatic
: ally higher, especially at low speeds. This is often refer
: red to as bleeding energy.
: This put together tell you that the induced drag is predom
: inant at low speeds and whenever you are turning, and the
: friction drag is predominant at high speeds.
: Now we?re back to the Corsair quiz, the interference drag.
:
: The friction drag and the induced drag contribute at least
: 90% of total drag and the interference drag contribute th
: e balancing less than 10%, which means that it?s not as im
: portant as the other two.
:
: In glider design today the interference drag is becoming m
: ore and more important. The other two components of total
: drag have been reduced enough to make a reduction in inter
: ference drag a significant improvement.
:
: Now to another quiz:
: When a glider flies it trades altitude for speed, unless t
: here are thermals of rising air it will eventually regain
: contact with terra firma.
: The glider weighs some 500 kg, has a rope attached to it,
: a very long one which runs over a pulley to hang a weight
: at the other end.
: How much weight is required to compensate for the drag and
: make the glider fly without the sacrifice of altitude?
: (I know the answer for the glider but not for the Corsair!
: )
:
: Regards,
: Christer

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