Re: Laminar flow wings

On Sep 19, 12:06 am, Dudley Henriques <dhenriq...@xxxxxxx> wrote:
Eunometic wrote:

Nice post. I'll inform Tolstoy he has competition :-))

I would add from personal experience with the D model P51 that the
internal main tanks held 92.7 and 92.1 gals of which 90.4 and 90.0
respectively was usable, not 85 gals, (don't know about the early
models)

85 Imperial gallons: Depends on who published the book your using and
who flew it. The Mustang was after built to British specifications
and they used the Merlin engined version as a coastal command escort.
My "great book of planes" has fuel
capacities in Imp gallons as well as cutout drawings of the fuel tank
location.


and the stall in the 51 is gentle and not "nasty" even with
power on. With power, there is some left roll off if the stall breaks
with an off center ball but even then easily recoverable by reducing
angle of attack. Stall recovery is normal in the Mustang and should in
no way whatsoever require 8000 feet to recover.
Now spins with power are another story :-))

Yes its spin I meant to refer to; 8000ft recovery is of course
ludicrous for a simple stall. Spin, a possible outcome from harsh
maneuvering and turning required several thousand feet to recover. An
oft quoted number is up to 8000 feet for the P-51.

The Fw 190 also had a mild stall however under harsh maneuvering it
could also enter a spin. The Fw 190 used 23015.3 airfoils at the
root and 23009 at the tip. These had very good L/D ratios but a
sharper stall characteristic than the 4 digit series used on for
instance a spitfire. The wing had a two degree twist starting at the
root that went to 83% (or so) of wing span whereupon the twist
stopped.

Due to the twin spar structure the 190 was very rigid and could roll
at high rate due to a relative absence of aeroelastic twist of the
wing box. A side effect seems to have been that the twist, mild as it
was in due to the twin spar wing, was such that it could increase
angle of attack and lead to a stall spin whenmanouvering with little
warning. What was good for rolling was not so good for turning. Once
within the spin the distortion would abate and the aircraft could be
recovered relatively easily. It was on some occasions used as a
tactical escape maneuver. (Caution; 190s had their wing structure
changed more than once and some allied tests of captured aircraft had
improperly adjusted controls)

The P-51s lengthier spin recovery is probably related to the center of
pressure and big slab sided fuselage effecting longitudinal
stability. The addition of a fillet to the tail fin in the bubble
versions indicates a longitudinal stability concern. The Lednicer

The NAA/NACA 45-100 used on the P-51 was very thick both at the roots
and tips (over 15.5% and 14.5% I seem to recollect) and it should
have been easy to make the wings torsionally rigid. It was this
paradoxical thickness, fuel capacity, freedom from compressibility
effects that gave the P-51 good speed and range and helped with the
high speed roll when internal pressure balancing was added to the
ailerons.

*********************

Something that I won't to add to my original reply for the first
poster: "guy". The laminar flow wing of the spiteful and Atacker may
have been the same however in the Jet the negative effects on handling
of gyroscopic precession (the swing) from the propeller are absent as
well as the effects of swirl from the propeller. Contra rotating
propellers often make aircraft with poor handling into ones with
superb handling.





.

Relevant Pages

  • Re: Fw-190 Vref ?
    ... Brown gives the stall as127mph clean, with no warning and violent port ... The wing drop occurred during high g turns and was caused by aero ... of attack which then promoted a spin. ... We saw Heino ...
    (rec.aviation.military)
  • Re: Cable break recovery spin entry... as previously discussed
    ... above stall speed. ... > recovery for any impending or developed stall is to move the ... > control column forward while applying coordinated aileron and rudder to ... > not spin, even if I held the stick firmly against the rear stop. ...
    (rec.aviation.soaring)
  • Re: About Stall Psychology and Pilots
    ... It's interesting to note that although stall recovery should be thought of as something done with a minimum loss of altitude, the emphasis on recovery should always be placed on the regaining of angle of attack as PRIME to recovery. ... For spin, PARE. ...
    (rec.aviation.piloting)
  • Cable break recovery spin entry... as previously discussed
    ... recovery for any impending or developed stall is to move the ... control column forward while applying coordinated aileron and rudder to ... in section 3.4 "Stall Recovery"- ... not spin, even if I held the stick firmly against the rear stop. ...
    (rec.aviation.soaring)
  • Re: Ping - Ed Rasimus - Can you cartwheel a Phantom ?
    ... inline reply, pilot to pilot. ... spiral dive, not quite the same as a flat spin :-), but it ... The theory being the wing has removed ... procedure for recovery that the student was required to demonstrate. ...
    (rec.aviation.military)
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