Author Topic: Wingload - tables for AH planes (Read 6861 times)

artik · « **on:** December 13, 2003, 07:10:03 AM »

Anybody has tables of wingload for AH planes?
Stall speeds?
Coner speeds?

We have exccelent graphs for Climb and Speed however I'd like also to have also information about wingload, stall/coner speed.

Angus · « **Reply #1 on:** December 18, 2003, 12:09:03 PM »

Hello there Artik
I have not seen this summed up in one particular but I'll give you a link with very good general information about most ww2 aircraft.
You should be able to figure it out from there. Of course wing loading varies with weight, so it's best to use empty weight as a comparative figure, - unless you can get typical operational weight (fighters fully armed and fuelled without ordnance for example). It's really a nice thing to put into Excel. then you can put max and min numbers and have it graphed out for instance.
As far as I know, the figures on these pages are correct, save possibly some climb numbers (maybe those are not using the same source so there is an error in the weight). But empty weight, full weight and wing area should be right.
Here is the link, best of luck:

http://www.xs4all.nl/~fbonne/warbirds/ww2indexpages.html

GScholz · « **Reply #2 on:** December 19, 2003, 06:11:10 AM »

The important thing is liftloading. Only wingloading don't tell you much.

You can calculate liftloading by dividing wingloading with maximum lift coefficient; LL = Weight/(Wingarea*Max_Lift_Coeff.

Here are some numbers (although I cannot guarantee their validity since they are from a second hand source):

Aircraft / Weight [lb] / Aspect Ratio / Max. Lift Coefficient / Wing area [ft^2] / Liftloading [lb/ft^2]

Spit I / 6050 / 5.62 / 1.12 / 242 / 22.3
109E4 / 5600 / 6.0 / 1.48 / 174 / 21.7
P-51B / 9400 / 5.815 / 1.28 / 234 / 31.4
Spit9 / 7450 / 5.62 / 1.12 / 242 / 27.5
109G6 / 7159 / 6.0 / 1.48 / 171 / 28.3

F4UDOA · « **Reply #3 on:** December 19, 2003, 02:10:40 PM »

Gsholz,

How are you calculating Cl max?

GScholz · « **Reply #4 on:** December 19, 2003, 02:38:31 PM »

I have no idea.

Angus · « **Reply #5 on:** December 19, 2003, 05:38:10 PM »

Don't really how CL is found out. However, the CL formula sometimes collides with actual data.
Maybe an imperfect formula?

GScholz · « **Reply #6 on:** December 19, 2003, 05:58:03 PM »

Huh? What do you mean?

Urchin · « **Reply #7 on:** December 20, 2003, 10:08:14 AM »

I think what he means is that sometimes those "calculations" don't match real life.

For instance, the 109E having lower "Liftloading" (which I've never heard of) than the Spit I indicates what? That it should turn better?

HoHun · « **Reply #8 on:** December 20, 2003, 11:58:57 AM »

Hi Urchin,

>For instance, the 109E having lower "Liftloading" (which I've never heard of) than the Spit I indicates what? That it should turn better?

Well, the Me 109E certainly should compare more favourably to the Spitfire I by lift loading than by wing loading because the Spitfire reaches a relatively low maximum lift coefficient only while the Me 109E reaches a comparatively high one thanks to the slats it uses.

(I'm not sure the quoted figures are correct, though - I thought the Spitfire got to around 1.22, for example.)

In any case, the immediate impact of lift loading only concerns instantaneous turn rate. Sustained turn rate is determined by the balance between power and drag.

On the other hand, wing loading has no immediate impact at all and can only be used to compare aircraft with identical wings :-)

Regards,

Henning (HoHun)

F4UDOA · « **Reply #9 on:** December 20, 2003, 02:24:24 PM »

Gsholz,

The clmax thing is funny. The P-51 cl max you have is from a NACA report where it has no prop installed on the airplane. This always shows a much lower Clmax than real life because even when an airplane is flying with power off the prop is windmilling or idle this raises Clmax. Most flight manuals list stall speeds with power on/off clean condition and power off/on in landing condition which usually includes flaps. Also this is always for a specific weight.

The equation for Clmax is one of the easiest to learn because you don't need much data.

Weight * 391 / velocity^2 * wing area

When this is calculated it uses TAS for the stall speed/volocity and the 391 accounts for air density at sea level.

American A/C and British A/C are super easy because they all list stall speeds at specific weights in all conditions. European A/C are more challenging.

The F4U-1D stall clean idle power at 11,300LBS is 96.6MPH.

So

11,300* 391= 4418300 / 96.6^2 * 314= 2930110

4418300 / 2930110

Clmax= 1.5

If you check the same NACA report the P-51 Clmax came from the F4U's Clmax is even lower than the P-51 at 1.17.

If you find stall data for the 109 the numbers are easy to plug in and calculate.

HoHun · « **Reply #10 on:** December 20, 2003, 03:42:53 PM »

Hi F4UDOA,

>The clmax thing is funny. The P-51 cl max you have is from a NACA report where it has no prop installed on the airplane.

If you're using lift loading as an indicator for manoeuvrability, then this might actually be the most appropriate value to use as the slipstream effect diminishes with speed. The problem is that it can only be found for a few aircraft types, which has an impact on comparability.

Here's some data from the graphical Me 109E vs. Spitfire comparison that has repeatedly been posted on several boards:

Spitfire (6000 lbs, 1050 HP @ 3000 rpm = 6.5 lbs/sqin, w = 24.8 lbs/sqft)

vs.

Me 109 (5600 lbs, 1200 HP @ 2400 rpm @ 12000 ft, w = 32.2 lbs/sqft)

Clmax table ("Assumed value of Clmax at full throttle"):

Gs Spitfire Me 109
1.0 1.87 1.95
1.5 1.65 1.70
2.0 1.52 1.60
2.5 1.47 1.52
3.0 1.45 1.49
4.0 1.43 1.47
5.0 1.42 1.45
6.0 1.38 1.44

You can see the effect of propeller slipstream dropping off with increased Gs, which of course coincedes with increased speed.

Regards,

Henning (HoHun)

HoHun · « **Reply #11 on:** December 20, 2003, 04:36:22 PM »

Hi again,

>Clmax table ("Assumed value of Clmax at full throttle"):

I've just re-read NACA report "Stalling Characteristics of the Supermarine Spitfire VA Airplane":

"The maximum lift coefficient reached in turns from level flight with flaps up was 1.22."

(From the graphs, I'd say the turns for this test were done at around 3 G.)

Maximum lift coefficients from the report (gun ports covered/open):

Flaps up, gear up, throttle closed: 1.12/1.15
Flaps up, gear up, 3 3/4 lbs/sq in, 2650 rpm: 1.63/1.58

So judging from these tests, it seems that the Clmax assumptions for the Spitfire I posted above are a bit too high actually.

From van Ishoven's "Me 109", there are figures for the Me 109 (at 5580 lbs) that indicate a 1 G Clmax of 1.38 with slats open, flaps up (unfortunately, no throttle setting is given) and a Clmax of 1.92 slats open, flaps down. The source of his figures is not entirely clear though - as everything is in Imperial units, I'd say it must be RAE tests.

The figures are highly interesting in showing a 20 mph mismatch between indicated and calibrated air speed at high angle of attack. While the stall speed actually was 95.5 mph, the airspeed indicator showed just 75 mph. This effect makes it difficult to get accurate Clmax data from manual figures.

Regards,

Henning (HoHun)

GScholz · « **Reply #12 on:** December 20, 2003, 07:29:15 PM »

I told you guys in my first post that my numers (not really mine) are NOT reliable. However my argument still stands that "liftloading" is more telling than "wingloading" to determine which AC turned better (which I think was the purpose of this thread). The formula should be good as long as you have good numbers to use in it.

F4UDOA · « **Reply #13 on:** December 20, 2003, 09:01:47 PM »

Gsholz,

I know that data can be hard to come by. I do have a document that shows the 109J and the "V lande" to be 150KM at 3,000KG. I believe that is 93MPH at 6,613LBS giving a Clmax of 1.38. I don't know if this is power on or not or even if flaps are being used.

I will post the doc when I upload it to my webpage.

gripen · « **Reply #14 on:** December 21, 2003, 04:17:41 AM »

IMHO Clmax for 1g, liftloading for 1g and wingloading are all about as relevant (or useless) for turning performance comparisons. Generally instantaneous and sustained g loading during maneuvering is much more than 1 g; a plane can't turn at 1g stall speed. More relevant comparison might be clmax for say 3 g or complete v/g flight envelope based on real world tests just like RAE did with Spitfire I and Bf 109E.

gripen