Peter Stickney wrote:

In article ,
Guy Alcala writes:
The Revolution Will Not Be Televised wrote:

On Sat, 06 Sep 2003 19:07:13 GMT, Guy Alcala
wrote:

Not yet, but I've got a bunch of B-25/B-26 books on order from various libraries,
so hopefully they will have something useful. I've also been reading Alfred
Price's "Spitfi A Complete Fighting History," which has some interesting info
on Mk. V fuel burn, range, Spit drag, etc.

The most useful I found were the Merlin 45/46 consumption figures with
relevant TAS figures with associated rpm and boost.

That was one I was thinking of, but if you've seen it that will save me some typing.
I think Pete will find the drag numbers more interesting, but maybe he'd want to see
the Mk. V fuel burn numbers as well. If he does and you've got a scanner (I don't),
could you send them to him?

I'd love to see it, if I could. If you can't scan it, or cost is an
issue, or it's just too danged big (sheetfeed scanners are a Good
Thing), than photocopy it, and mail it, if you wish. I'd be happy to
scan it for you.

I haven't seen a reply from Gavin to this, so I'll just type the info in. This is from an
official memo sent around to the Fighter stations in August 1942, titled "How to Make Full
use of the Performance of the Spitfire V, VI, and IX." The fuel consumption data is from
Appendix A, "Spitfire VB and VC (Merlin 45 and 46): Approximate Petrol Consumption Figures
at Various Boost and Rev Settings." I'm going to list the data in the format ASI / TAS /
Height / Boost / Revs / Consumption in gal./hr. An asterisk following the latter says to
"Fly at these settings" (for max. range at the specified speed/height):

250 / 255 / 2000 / +4 1/2 / 2000 / 42

230 / 234 / 2000 / +2 3/4 / 1800 / 35*

- / - / 2000 / + 1/2 / 2650 / 40

200 / 203 / 2000 / - 1/2 / 1800 / 31*

- / - / 2000 / -2 1/2 / 2650 / 35

295 / 331 / 10000 / +9 / 3000 / 88

- / - / 10000 / +6 / 2650 / 70

250 / 281 / 10000 / +3 3/4 / 2000 / 42*

- / - / 10000 / +2 / 2650 / 47

200 / 225 / 10000 / -1 1/2 / 1800 / 29*

- / - / 10000 / -3 / 2650 / 35

283 / 368 / 20000 / +9 / 3000 / 88

268 / 350 / 20000 / +6 / 2650 / 70

258 / 300 / 20000 / +3 3/4 / 2650 / 65

240 / 310 / 20000 / +3 3/4 / 2400 / 50

230 / 300 / 20000 / +1 1/2 / 2400 / 46*

- / - / 20000 / +1 / 2650 / 48

200 / 263 / 20000 / -1 3/4 / 2200 / 36*

- / - / 20000 / -2 1/2 / 2650 / 40

216 / 335 / 30000 / +0 / 3000 / 47

180 / 283 / 30000 / -3 1/4 / 2850 / 41*

- / - / 30000 / -3 1/4 / 3000 / 43

Note that the 300 TAS entry for an ASI of 258 mph @ 20,000 feet is clearly a typo, either in
Price or the original. It probably should read 330 or more likely 340 TAS. The report also
states that Mk. V fuel consumption at +16 / 3000 is 150 gph. One of the paragraphs in the
report states "Spitfires are now modified to give +16 emrgency boost. It must be impressed
on pilots that this gives a great increase of speed under 21,500 feet and 18, 250 feet for
Merlin 46 and 45 engines respectively, and that if used for combat only there is no risk of
engine failure."

Here's the drag data promised, for the Mk. I. The drag is measured in pounds at a notional
speed of 100 ft./sec:

Profile Drag:

Wings, 20.3

Fuselage, 7.3

Tailplane, Fin and Rudder, 4.6

Effect of Camouflage Paint, 1.5

Total Profile Drag, 33.7


Induced Drag:

Lift, 2.4

Washout, 0.6

Total Induced Drag, 3.0


Cooling Drag:

Glycol Radiator, 6.0

Oil Radiator, 1.0

Air Intake, 1.0

Total Cooling Drag, 8.0


Miscellaneous:

Controls, 1.2

Windscreen, 1.2

Tail Wheel, 2.0

Wing/Body Interference, 1.5

Aerial Post, 0.2

Gun Holes, 0.5

Rivets and Joints, 0.5

Total Miscellaneous, 7.1


Not Accounted For, 8.4

Total Drag of Aeroplane, 60.2

There's also a fairly detailed weight breakdown for a Mk. I, but enough typing for now.

Guy