Author Topic: Weight, Power, Wing Area (Read 356 times)

F4UDOA · « **on:** March 21, 2002, 12:30:21 PM »

Heya's

Just wanted to put together some data which may dispell some Myth's about capabilties of certian A/C types. I really want someone to do the same thing for Euro-types, Japanese and Russian as well. At least in the Fighter role anyway.

I'm doing this because of some miss-understanding about the Me110 and it's surprising performance. I certainly can't dispute it because I do not have what I consider to be accurate data but if someone does please post it. I consider accurate to mean a source document or Pilot's manual.

First I am ranking American Fighters based on Wing Loading best to worst. Their are 11 American Fighter A/C in AH today.

Wing Loading Combat loadout Best to worst (Weights from AH Charts)

1. F6F-5 12,483LBS WingArea 334SqFt = 37.37
2. F4U-1 12,039LBS WingArea 314Sqft = 38.34
3. F4U-1D 12,175LBS WingArea 314Sqft = 38.77
4. P-51B 9,245LBS WingArea 235.75SqFt = 39..21
5. F4U-4 12,420LBS WingArea 314SqFT = 39.55
6. F4U-1C 12,470LBS WingArea 314SqFt = 39.71
7. P-51D 9,611LBS WingArea 235.75SqFt = 40.76
8. P-47-11 13,582LBS WingArea 300Sqft = 45.27
9. P-47-25 14,500LBS WingArea 300Sqft = 48.33
10. P-47D30 14,500LBS WingArea 300Sqft = 48.33
11. P-38L 17,500LBS WingArea 327.5Sqft = 53.43

Power Loading Sea level. Best to worst

1. F4U-4 12,420LBS HP= 2450 = 5.07
2. F4U-1D 12,175LBS HP=2250 = 5.41
3. P-38L 17,500LBS HP=3200 = 5.46
4. F4U-1C 12,470LBS HP=2250 = 5.52
5. F6F-5 12,483LBS HP=2250 = 5.54
6. P-47-D30 14,500LBS HP=2600 = 5.57
7. P-51D 9611LBS HP=1720 = 5.58
8. F4U-1 12,039LBS HP=2135 = 5.63
9. P47D11 13,582LBSHP=2300 = 5.9
10. P-51B 9,245LBS HP=1490 = 6.2
11. P-47D25 14,500LBS HP=2300 = 6.3

Drag Coefficients from Vought Museum best to worst.

1. P-51B/D = .017
2. F4U-1/4 = .020
3. P-47D = .022
4. F6F-5 = .023
5. P-38L = .028

If anybody could do the same for other fighter types I would greatly appreciate it.

Thanks

Virage · « **Reply #1 on:** March 21, 2002, 12:41:15 PM »

Very interesting. Looking forward to seeing the other A/C.

AH 47-11 is the first thing that jumps out at me. Must be those spit wings

Tub-o-lard · « **Reply #2 on:** March 21, 2002, 07:26:02 PM »

What fuel level are these numbers for?

MANDOBLE · « **Reply #3 on:** March 21, 2002, 07:49:15 PM »

I suppose the units are not the same, but here you have more drag cofs:

http://jagdhund.homestead.com/files/DoraData/aerodynamics.htm

F4UDOA · « **Reply #4 on:** March 22, 2002, 09:52:26 AM »

Mandoble,

Thanks for those numbers. I haven't seen anything for the Spit before.

The Spitfire and drag is a curious thing. Even the Spit XIV which had the 2000+HP engine only did 360MPH on the deck compared with several different 109's, FW190 and P-51 all with the same or less HP can reach higher speeds at sea level. The only explanation being higher drag of the Spit. It is strange because the Spit looks so clean a design. I have read it was the radiator design that slowed it down.

Tub-O-Lard,

All the fuel loads are 100% internal fuel except the P-51D and F4U-1(early). I took the weights from the AH web page. They are representitive of what would be a "combat" loadout in most cases except the F4U-1, P-51D and possibly the P-38L.

Naudet · « **Reply #5 on:** March 22, 2002, 10:07:31 AM »

F4U, i would be interested, why the numbers for the drag coefficient differ so much.

your CD for P51 is 0.017 and the one on Bryans Webpage is 0.0052

F4UDOA · « **Reply #6 on:** March 22, 2002, 11:42:36 AM »

Naudet,

They are expressed differently because the European calculations are expressed in metric I beleive. I really don't know how to convert them myself. I will email these to Wells and let him do the Math, Hehe.

wells · « **Reply #7 on:** March 22, 2002, 08:48:53 PM »

Drag coefficients are unitless, so it's not a metric thing.

One value (0.017) is based on wing area, the other one on total wetted surface area, including fuselage, tail surfaces (top and bottom), canopy, you name it!

0.005 * 800 sq ft is the same as
0.017 * 235 sq ft

I wrote a little computer program that will calculate Cd0, best climb speed and rate, best glide speed and ratio, best range speed and sustained turn performance at different altitudes in some interval. It's a work in progress, but it can spit out a lot of useful data quickly and beats using spreadsheets! heheh

If anyone wants to play with it, you can grab it here:

prop_aero_17.zip

Check the readme file for more info. There's a few sample files in the zip.

hazed- · « **Reply #8 on:** March 22, 2002, 09:08:24 PM »

you dont know how to convert metric etc????

just use this and pretend you can do it in your head

http://www.initium.demon.co.uk/converts/metimp.htm

F4UDOA · « **Reply #9 on:** March 24, 2002, 11:52:16 AM »

Hazed,

I know how to convert metric. But when you don't know what unit of measurement you are using it is difficult. And as Wells said it is not a metric conversion after all.

Wells,

I tried your spread sheet. It seems to have some errors I think.

1. The example you used of the F4U-1 when an input of 100 for the altitude interval was given it showed a decrease in climb rate at lower altitudes.

2. It also showed a decrease in HP at lower altitudes.

3. The Cdo listed for the F4U-1 was .0170. I think this is low even by my standards.

Also some of you input data seemed a little unusual for the F4U-1 compared to the P-38. You have it list as design speed. Is this sea level speed or max speed at alt. In any case you have it listed as 343Knots for the F4U and 363knots for the P-38. Also you have stall speeds listed as 100knots for both A/C. They both seem a little off.

You may want to take a quick look.

Thanks

wells · « **Reply #10 on:** March 24, 2002, 12:22:53 PM »

DOA,

I probably shouldn't have put the F4u in that package, since it didn't do 2-speed superchargers at the time, heheh. It does now! I updated the link. Please try it again, it seems to be working fine. Power does reduce below rated height (except for turbos). Notice that the F4u uses a slightly higher manifold pressure to get 2000 hp for takeoff than it does at 1700 ft for the same power. The sample files may not be totally accurate. I just threw them in there to use as templates. I fully expect someone to change the values to match their data.