Author Topic: Books on the Spitfire (Read 1389 times)

Angus · « **Reply #15 on:** July 31, 2004, 07:24:54 AM »

The Spitty has a rather unfavourable aspect ratio, - a sacrificial cost of keeping the wing elliptical.
A better aspect ratio will result in relatively less induced drag, while the Ellipse also reduces it somewhat (5-10%)
The result is an aerobatics wing rather than a pure speed wing.

Crumpp · « **Reply #16 on:** July 31, 2004, 07:45:40 AM »

Good info, thanks Angus!

Crumpp

Angus · « **Reply #17 on:** August 01, 2004, 09:41:35 AM »

You're welcome

There is one aerobatics aircraft with an elliptical wing, just can't remember the name at the moment. I can try to dig something more up about it if you like.
Anyway, it is told to be absolutely delightful, and is able to go through a series of maneuvers with very little power without loosing altitude.
Although the aspect ratio of an ellipse is rather unfavourable, the ellipse makes up for it in two ways.
1. The shape gives less drag than expected for a wing in any other shape with the same aspect ratio. (tapered, stubby), the difference being in the range of 5 - 10 %
2. A side effect of an ellipse is the wide chord. It will give some pluses at extreme angles. Hence the upwards corkscrew escape maneuver of Spitties.

Crumpp · « **Reply #18 on:** August 01, 2004, 10:12:20 AM »

It also exlains why Spit pilots didn't fight in the vertical against 190's.
That elipitical wing was nice. For sustained turns and slow speed climbs it was unbeatable.

At high speed turns and zoom climbs the aspect ratio hurts it.

Crumpp

Angus · « **Reply #19 on:** August 01, 2004, 10:37:29 AM »

Si si, it creates lift at all possible angles, also when not needed. Lift creates drag in the process.....

Crumpp · « **Reply #20 on:** August 03, 2004, 05:24:45 AM »

Angus,

What do you make of this:

Weight gain and wingloading

Spitfire Mk I - 5,935lbs Take off wt
WL-24lbs/sq. ft

Spitfire mkVb - 6525lbs Take off wt (2 x 20mm, 4 x .303)
WL - 28lbs/sq. ft

Spitfire Mk IX - 7,480lbs Take off wt
WL - 30.9lbs/sq. ft

Spitfire Mk XIV - 8,488lbs Take off wt
WL - 35lbs/sq. ft

Total Weight Gain = 2,553lbs
Wingloading increase = 11lbs/sq. ft

This is what I thought was interesting too:

Quote

Turning Circle
18. The turning circles of both aircraft are identical. The Spitfire XIV appears to turn slightly better to port than it does to starbord. The warning of an approaching high speed stall is less pronounced in the case of the Spitfire Mk XIV.

http://www.fourthfightergroup.com/eagles/spit14afdu.html

Hp Increase can be checked with the HP charts on the same website. Spit Mk XIV gains roughly 400 hp over the Mk IX.

------------------------------------------------------------------------------------

Weight gain and Wingloading (all varients have full wing armament)

190A3 - 8770lbs Take off wt
WL - 43lbs/sq. ft

FW190A5 - 9052lbs Take off wt
WL - 44lbs/sq. ft

FW-190A8 - 9418 lbs Take off wt
WL - 46lbs/sq. ft

Total Weight gain - 648lbs
WL Increase - 3 lbs/sq. ft

Usable Hp Increase - 350hp to 450hp depending on the source.

Why is the FW-190A8 considered such a Pig?
Why is the FW-190 considered to have gained so much weight?

Crumpp

MiloMorai · « **Reply #21 on:** August 03, 2004, 06:25:33 AM »

If you used the correct TO weight for the 190A-8 your number would be different.

Technical description No. 284 (for the A-8)

Weight distribution (in kg)

Fuselage - 345.2
Undercarraige - 258.3
Control surfaces - 120.8
Flight controls - 32.3
Wing assembly - 475.0
Powerplant - 1661.3
Standard equipment - 248.1
Permament accessories - 27.4
Additional accessories - 319.3
Paint - 2.0

Empty weight - 3489.7 > 3490

Pilot, parachute, flying gear - 100
Normal fuel - 410
Aux. fuel tank(115l) - 90
Lubricants - 50
Ammo(MG131 - 2x75) - 77
Ammo(MG151 - 2x250) - 110
Ammo(MG151 - 2x140) - 64

Useful load - 901.0

Flying weight - 4391.0 > 4400kg (9682.2 > 9702.0lb)

Your TO weight for the A-3, a tad high?

Empty weight - 2833kg
Fuel - 400kg
Oil - 50kg
Crew - 80kg
Load - 532kg
TO weight - 3895kg (8587lb)

A weight increase of 1115lb from A-3 to A-8.

MiloMorai · « **Reply #22 on:** August 03, 2004, 06:39:26 AM »

Quote

Originally posted by Crumpp

Weight gain and Wingloading (all varients have full wing armament)

190A3 - 8770lbs Take off wt
WL - 43lbs/sq. ft

8770/197 = 44.5

FW190A5 - 9052lbs Take off wt
WL - 44lbs/sq. ft

9052/197 = 45.8

FW-190A8 - 9418 lbs Take off wt
WL - 46lbs/sq. ft

9418/187 = 47.8

18.3^2m = 196.986^2ft

Crumpp · « **Reply #23 on:** August 03, 2004, 01:06:53 PM »

I am using the FULL take off weight Milo. The weight for the full wing armament FIGHTER version. Pyro has a copy of the weight breakdowns. They come right out of the pilots manual and are broken down by varient type.

You can buy a copy from:

http://www.luftfahrt-archiv-hafner.de/

Crumpp

Crumpp · « **Reply #24 on:** August 03, 2004, 01:20:16 PM »

Your weights are right on EXCEPT for your empty wieght Milo.

It corresponds closely with the listed empty weight of a 190A8 Jabo-einsatz with 4 MG151's @ 3898kg empty weight.

The weight of the FW-190A3 is the version the RAF tested with outboard MgFF's. The wieght of the other fighter version IS lighter but does not include the outboard cannons.

It was tested against a Spitfire Mk IX with Merlin 61(+15) boost.

Crumpp

MiloMorai · « **Reply #25 on:** August 03, 2004, 01:32:17 PM »

Crumpp · « **Reply #26 on:** August 03, 2004, 01:51:05 PM »

Nope,

Just saying it is not the fighter version as the LUFTWAFFE manual says.

Crumpp

MiloMorai · « **Reply #27 on:** August 03, 2004, 01:59:03 PM »

Quote

Originally posted by Crumpp
I am using the FULL take off weight Milo. The weight for the full wing armament FIGHTER version. Pyro has a copy of the weight breakdowns. They come right out of the pilots manual and are broken down by varient type.

You can buy a copy from:

http://www.luftfahrt-archiv-hafner.de/

Crumpp

Well you can go and tell FOCKE-WULF their doc Technical description 284 for the A-8, dated 9.8.44, is a load of dung.

Notice that this is for the FULL fighter version as the weights for the 4 20mm cannon and MG131s are given.

MiloMorai · « **Reply #28 on:** August 03, 2004, 01:59:04 PM »

post x2

Crumpp · « **Reply #29 on:** August 03, 2004, 02:05:11 PM »

So my question still stands:

Why is the 190A8 considered to be such a pig? Angus, do you have any insight into this?

1. The FW-190 gained much less weight over it's life span than the Spitfire AND gained the equivilent Horsepower.

2. The wingloading increased only 3 lbs over it's lifespan.

Crumpp