GrauGeist
Generalfeldmarschall zur Luftschiff Abteilung
Nope, it was "Winkle"
Griffon Spitfire was better than any Bf109?
- Thread starter ROK-BIRDMAN
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- bf109 spitfire spitfire fr xiv
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Everyone goes on about Brown, but his boss was a far better known pilot during his tenure at the RAE
FLYBOYJ
"THE GREAT GAZOO"
What's your point? At the end of the day Brown had more hours in the air and flown more aircraft than his boss ever could. Give it up mate, you put your foot in you mouth when you made your initial comments about Brown with little or nothing to backup your claims.
Jabberwocky
Staff Sergeant
Nitpick: Merlin is a 27L engine.
Engine weights per Rolls-Royce data (Some sources site a 2.5% tolerance, a few other sources say a 21 lb tolerance)
M I weighed 1320 lb dry (600 kg)
M III weighed 1385 lb (630 kg)
M XX weighed 1450 lb (659 kg)
M 61 weighed 1640 lb (744 kg)
M 66 weighed 1645 lb (748 kg)
Weight gain of 24.6%.
Merlin engine Spitfire engines gained 18.7% in weight during wartime service (M III to M 66)
Griffon engine weights:
G IV weighed 1900 lb (862 kg)
G VI weighed 1790 lb (812 kg)
G 61 weighed 2075 lb (941 kg)
Weight gain of 9.2%.
Spitfire engines overall gained 49.3% (M III to G 61) during wartime service
DB 601 weights from RLM (stated 3% tolerance)
601A-0 weighted 590 kg dry
601A-1 weighed 610 kg
601N-1 weighed 610 kg (another data sheet has 635 kg)
601E-1 weighed 660 kg
Weight gain of 11.9%
DB 605 weights
605 AM weighed 730 kg
605 AS weighed 730 kg
605 ASM weighed 730 kg (also 755 kg on a different data sheet)
605 DB weighed 745 kg
605 DC weighed 745 kg
605 L weighed 770 kg
Weight gain of 5.5%
DB601 to DB605 weight gain of 23.4%.
109 engines gained 26.2% over the course of the war (DB 601A to DB 605 DB/DC). If you include the rare 605 L then that goes up to 30.5%.
I never realised just how much engine weight the Spitfire packed on during the war! Basically 50% (just shy of 700 lbs).
GregP
Major
Yes, the 37 was a typo. Sometimes happens and did this time. The rest is accurate, at least for a 60 series model.
Deleted member 68059
Staff Sergeant
- 1,058
- Dec 28, 2015
You can probably find a list of drag coefficients online somewhere (maybe even this forum). However the later G`s and K`s had utterly appauling build quality and were a good 5% down on top speed due to this. The later very high boosts allowed on the K were in fact just about enough to get it back up to the factory figures.
The Spitfire by then was also a pretty bulbous thing with loads of bumps and the like, and the radiators were monstrous, with fairly poor ducts as they had no room
to put in ideally proportioned ducting anymore (proximity to the wheel-wells).
Both pretty well at the end of their development and dragged through the sky by brute force, I`d say.
SaparotRob
Unter Gemeine Geschwader Murmeltier XIII
But they look cool.
From what I have read the Bf 109 was poor in its aerodynamics, although it is small and looks sleek.
Shortround6
Major General
It was poor, small size is not a sign of cleverness.
One chart gives the following "equivalent flat plane area for 3 US fighters"
Brewster F2A-3......................................6.27 sq, ft
Republic P-47B......................................6.39 sq ft
Grumman F4F-3....................................6.58 sq ft.
Considering the size and weight of the P-47B, maybe there is a typo but when you have a large airplane showing about the same total drag as a much smaller airplane you have figure the small plane is screwed up somewhere,
One chart gives the following "equivalent flat plane area for 3 US fighters"
Brewster F2A-3......................................6.27 sq, ft
Republic P-47B......................................6.39 sq ft
Grumman F4F-3....................................6.58 sq ft.
Considering the size and weight of the P-47B, maybe there is a typo but when you have a large airplane showing about the same total drag as a much smaller airplane you have figure the small plane is screwed up somewhere,
Agreed.
Its interesting, isn't it? In a combat aircraft, how does one judge 'better aerodynamics'? Seems there are so many benchmarks.
Mach limiting number?
Drag coefficient?
Wing loading?
Power to weight / lifting capacity?
Top speed?
Climb rate?
Roll rate?
Turning circle?
Harmony of control?
Behaviour at the stall?
Stability as a gun platform versus manoeuvrability?
Operational ceiling?
(and all these in turn potentially influencing cost and ease of production, structural strength, adaptability of the basic design, time to train a pilot to make maximum use of the planes attributes, weapon load, engine and weapon compatibility, likely non combat operational losses due to handling, range etc etc etc)
and on and on....
From what I've read too, it seems to me that whilst the BF 109 was good in many of these areas, and the two aircraft leapfrogged each other from time-to-time during their development, the Spitfire overall was able to excel in more of these areas, and for for a longer time.
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I googled 'flat plane area' and saw the dreaded words 'calculus'. 'Fraid I chickened out!
Is there a layman's simple way of understanding what these figure mean and how they relate to aerodynamics?
I found this, which I believe is originally from a member of this forum called Dave, but as I understand it, the FPA represents all the ins and outs of drag in terms of a flat plate which can easilt be compared to others flat plate areas.
The concept of "equivalent flate plate area" comes from noting
that while:
Drag Where: Drag = resistance force
CD = ------------------ rho = density
.5 rho Vel^2 Sref Vel = Velocity
Sref = Ref Area
is nondimensional, the Sref is awkward, as how the reference area is
chosen can differ. So if we instead define:
Drag
f = -------------
.5 rho Vel^2
the Sref no longer appears, but f has the units of length squared. If
English units are used, you get the equivalent flate plate area (f) in
units of square feet. Note, this does not mean that a flate plate of
the same area as f would have the same drag - a flate plate has a CD of
roughly 1.17 (in 3-D flow, according to Hoerner and 1.98 in 2-D flow),
not 1 as implied in the equation! We can see this from:
Drag = CD .5 rho Vel^2 Sref
where Sref is the frontal area of the plate. Hence, the equivalent
flate plate area is:
CD .5 rho Vel^2 Sref
f = ----------------------
.5 rho Vel^2
So you can see that the flate plate of area Sref has an equivalent flat
plate area 1.17 times its true area (in 3-D flow)!
Perfect! Many thanks!!
S = Cd0 x wing_area
S - equivalent flat plane area
Cd0 - coefficient of drag at zero lift (aircraft flies at high speed at level flight)
wing_area - wing area
David Lednicer notes (he uses 'f' instead of 'S'; all in sq ft):
Spitfire IX - 5.40
P-51D - 4.65
Fw 190A8 - 5.22
Fw 190D-9 - 4.77
The lower the 'S' (or 'f') value, the better.
(my comment: it is easy to see why would one design a relatively small aircraft when aiming for outright speed; going too small limits the growth potential, however; FW data notes 0.485 sq m for the Fw 190A8, and 0.444 for the D9, or 5.167 and 4.78 sq ft respectively)
Hey SG, has you ever done any research on the Spits radiators or know of any work in regards to improving their efficiency?.
Deleted member 68059
Staff Sergeant
- 1,058
- Dec 28, 2015
The biggest step was probably the boundary layer splitter of the Mk-III, but as you know that Mark was cancelled, and the boundary layer splitter was never reinstated. The main (or at least one major) problem is that these things are quite hard to retrofit into an existing design, having the splitter reduced the space available for the cooling matrix, so it was quite difficult to realise the gain as you then either have to fit a deeper core or stick the radiator out into the breeze more.
Shortround6
Major General
I would note that the 109 ran into a similar problem. the 109F radiator set up was pretty good but with the 109G and the larger engine the boundary layer splitter that they uses in the 109F (air ducted up and over the matrix) either went away or was made smaller? In any case some of the sophistication went away and brute force (larger matrix) was substituted.
