The effect of 'clipping' Spitfire wings

[pasoleati]

Originally posted by Crumpp
Your absolutely correct Toad.

All high performance aircraft are capable of inducing an aggravated stall provided they can change the AoA faster than the wing can produce lift at a given speed.

Many aircraft, especially in the early war during WWII where not capable of doing this due to excessive stick forces at high speed.  In later war designs this phenomenon becomes more commonplace and is not quite as surprising as it was when it first appeared in the FW-190A.

It is interesting to note that no test pilots in Germany had ever seen the wings of an aircraft turn white with condensation in a high speed turn or seen it on the propeller tips until the FW-190 appeared.

The light stick forces of the FW-190 could actually be detrimental to its performance if flown by a heavy-handed pilot.

All the best,

Crumpp

Which early war aircraft might you mean? If we e.g. examined those older monoplane fighters in Finnish AF service (i.e. Brewster Buffalo, Curtiss Hawk, Fiat G.50, Fokker D.XXI, MS 406), they all have quite light stick forces.

[MiloMorai]

Originally posted by Kev367th
So to sum it up -

The flight test used -

A prototype Spit XII - Although their #s are BN221 and BN222, a mystery?
Mk F V's and an F IX ALL with engines designed for higher alts, flying at their usual alts with a clipped wing.

Kev, the numbers should begin EN. These were the first 2 Mk XIIs off the production line.

EN221 and EN222 were both at Boscombe Down Nov 6 1942 for intensive flying trials EN221 came off the production line Oct 13 1942.

[Naudet]

Both Oscar Boesch and Heinz Orlowski have told me you the FW-190 stick burbled before any stall.

I remember to have seen a LW report were both the stall characteristics of the FW190 and Bf109 were investigated.
It says excatly the same, that for a pilot used to the FW190 the stall would not come surprisingly as he would feel it in the control column. But properly ajusted ailerons were neccessary otherwise the warning was not so pronouced.

[Crumpp]

Well, that Beauvois quote was the primary quote I meant. Shouldn´t comments from a test pilot of Beauvois´s calibre carry more weight than statements from 2 next-to-unkown pilots.

Problem is Beauvais does not saying anything other than he could stall it at 400 mph.  It gives no insight to the amount or lack of warning.

I think you will find too that most of those early war aircraft do not have light stick forces at 400mph IAS.  Fabric Control surfaces and cable controls are a bad combination for high-speed maneuverability.

Now the FW-190 did have fabric control surface.  It also had a unique construction that eliminated ballooning.

Each riblet had a grooved trough where the attaching wires fit to keep everything flush.  3 layers of individually doped fabric then go over the surface.  The whole thing comes out completely flush.  I have seen visitors to the Museum argue that they are metal covered while standing a few feet away from the completed ailerons.

http://www.white1foundation.org/parts/elevators.jpg

Thank you Naudet for reminding me!  Here it is:





As for the "unknown pilots", I am willing to bet you did not have a clue who Heinrich Beauvais was until you picked up Hermann's book.  It's ok, I did not either until I started studying the FW-190.

Oscar Boesch:

http://chesterfieldarmament.com/bailey/warwolf/warwolf.htm

Heinz Orlowski:

A single Mustang (HB836) tried to help out, and attacked the German fighter. A long aerial duel developed. The Mustang finally caught fire, and made a wide turn out the fjord. Perhaps he will try to get away and make a crashlanding. But then the British pilot turned back. According to eyewitnesses the pilot must have been badly wounded, but instead of bailing out he continued the fight. But to no avail. The Mustang crashed in the green pine forrest being the only Mustang loss of this battle. W/O Cecil Claude Caesar was dead.

The German fighter was in trouble also. The engine had been damaged and this forced the pilot to bail out. A small charge dispensed with the canopy and a small figure detatched itself from the plane. But he was to close to the ground for the chute to open. Fortunately, the snowy hillside enabled the pilot to survive, a small avalanche carried him to the bottom of the valley. During the journey down, the flare gun accidentally went off, causing severe burns on one leg. Still, he can walk, and he found his way into a small barn. After a little while some Norwegians contacted him and made sure he got to hospital. This pilot was Heinz Orlowski. He spent the rest of the war in hospital and reconvalence at Herdla, and did not see further combat. In 1994 he and his newly-restored "Weisse 1" was actually reunited in Texas, survivors of a fierce battle some 49 years before.

http://www.white1foundation.org/history_blackfriday.htm

http://www.white1foundation.org/history_orlowski.htm

I think the polite thing is too start another thread if  you feel there is anything further to discuss on this issue.  

All the best,

Crumpp

[Angus]

Paseolati:
The Curtiss hawk as well as the P40 were good on the rolling.
They however had very good leverage and the space for it, as well as not too high top speeds.
Same goes to some early WW2 fighters.
Do you have some figures or graphs for the others you mentioned?
THX in advance

[Kev367th]

Originally posted by MiloMorai
Kev, the numbers should begin EN. These were the first 2 Mk XIIs off the production line.

EN221 and EN222 were both at Boscombe Down Nov 6 1942 for intensive flying trials EN221 came off the production line Oct 13 1942.

Ahhh, thanks.
So the question now becomes why have they got Griffon II's?Production Spit 12's had Griffon III or IV.

Dan-
What does your book(s) say about Spit BS139?

[pasoleati]

Originally posted by Angus
Paseolati:
The Curtiss hawk as well as the P40 were good on the rolling.
They however had very good leverage and the space for it, as well as not too high top speeds.
Same goes to some early WW2 fighters.
Do you have some figures or graphs for the others you mentioned?
THX in advance

Not graphs as such. My commets were based on the analysis of handling characteristics of those aircraft in Jukka Raunio´s Lentäjän Näkökulma vol. 2 (Pilot´s View vol. 2). Raunio´s text is based on various reports (incl. some British reports) and pilot manuals.

[Rafe35]

The British Vought F4U-1B Corsair with clipped wings (8 ins) seem to be improving on roll rate what British Navy pilots said, but Clipped wings Corsair actually for stored aboard British aircraft carriers which had lower hangar ceilings.

Rafe

[Angus]

Hey Paseolati, thx for the reply.
Analysis or just anything would be a nice post.
As for the Spitfire, already in 1939 it was an aircraft crabbing into unexplored speeds. Same goes to the LW, and probably the USA.
Aircraft were being made for combat service, that could so easily reach very high speeds, - like 300-400 mph.
As a sidenote, - was it the Hurricane that was the first squadron strength aircraft in military service to be able to sustain 300 mph at some given alt, - or the 109D?....or the P36????
Anyway, all sides had problems wth roll rates at some speeds. And there is a catch. At VERY low speeds, - near stall, - things like wing loading and span loading will affect it. Eventually a wing will stall at a given speed. Fly a tad above it's stall, - you will stall by banking. You will roll and fall without entering a turn, for controls are lost.
Stalls can be done at high speeds as well, so this is never too simple. Same goes with quick pulls under G.
The 190 was famous for  being able to enter maneuvers very quickly. It basically went "ROOFFF" and it had 180 degrees on you. Nice design basically.
The Spitfire did not have that rolling quality. Well, the ultimate ones perhaps. But in 1941-1942 the only thing the designers could do was clipping it. They did it for a purpose, it did more or less not match the rolls of the 190, but helped closing the gap.
That was the effect of clipping.
A little more speed, quite better roll, less high alt performance, worse turn rate.
A tradeoff, - as always.

[pasoleati]

Angus, mail me at paso.leati@pp.inet.fi

[Guppy35]

Originally posted by Kev367th
Ahhh, thanks.
So the question now becomes why have they got Griffon II's?Production Spit 12's had Griffon III or IV.

Dan-
What does your book(s) say about Spit BS139?

Looks like it was the 45th production Spitfire FIX and was used extensively for testing at Boscombe Down.  In August 42, 145 hours of test flying were done with BS139.  Original engine failed after 117 hours.  258 landings made.  9 tire changes.

later used for fuel tank testing, exhaust stack testing, spinning trials and dive recovery trials.

As for EN221 and 222, they had Griffon IIIs to start, if their individial record cards are to be believed.  I'm guessing it was a mistake in the report as DP845 had the Griffon IIB.  I have copies of all the record cards for the Spit XII and 221 and 222 both specify the Griffon III installed.  Other later MB serialed aircraft designate the Griffon IV.

Dan/CorkyJr

[Thrawn]

You know, I certainly wouldn't want Kurfürst to be removed from this board.  But, I would like him to actually participate in honest discourse instead of whatever the hell it is he is doing.

[Squire]

AH2 doesnt have a clipped wing Spitfire anyways...

In any case clipping the wing provided a small roll rate increase at lower alts and it would have had a small effect on turn performance, as it would with any fighter.

Vs, LF Vs, LF IXs, LF XVIs, VIIIs, XIIs and XIVs all used the clipped wing at certain times of the war: in the ETO, SE Asia and the Med, mainly when they were deployed in the low level role. There was a benefit to doing it otherwise they would not have bothered?

...Btw the conversion could be done or undone at the squadron level, clipped wing Spitfires could be fitted with "regular" wingtips and vice-versa. Same with the "extended" tips of the VII, they could also be fitted with regular wingtips, as they often were in 1944-45, as the high alt missions were less needed.

[Angus]

Small roll rate increase?
Quite a bit of a roll rate increase, yes?

Anyway, if the clipped ones were incorporated in AHII, it would be cool if it was a Hangar option

[Squire]

Improved roll rate of some quantity sure...suffice to say, it was of enough of a benefit to warrant the usage. Thats plain from reading any of the accounts of the type.

It also had better low level acceleration, and diving ability, and a 5 mph speed increase (in the Mk V series) from what my source has.

As for the conclusions of the RAF I beleive they decided that "clipping" the Spits wings were not reccomended *as standard*, in other words, to be used "as needed", which seems to be exactly what they did.

Also, the Royal Navy used the clipped wings on the Seafire LIIC and the Seafire LIII series from 44-45, in some squadrons, so they also saw a benefit. They did not need to follow the RAFs doctrines if they didnt want to.