Small wings/high wing loading of German fighters

[Shortround6]

Okay, but how do you explain that late-war the Germans still went with high wing load and their developments and new designs had smaller wings than the rest.
Only the Russian planes featured even smaller wings, but they were also a lot lighter.

Were they?

Smaller wing is one way to cut the drag. Lower the drag = increase the speed.
That design philosophy was also used several times in decades after the ww2.

The smaller wing "trick" was used quite extensively in the the 30s and most of WW II.
I am not saying the P-26 was the first but it may have been influential.

149-150 sq ft wing. A very fast plane for 1934-35. It also showed the pitfalls of small wings. An over 80mph landing speed. Which was somewhat solved by fitting flaps part way through the production run and refitting over 100 (?) previously built airplanes. Got the landing speed down to 73mph.
The Supermarine 224 landed at about 60mph and the Air Ministry wanted 50mph. Obviously they relaxed that to even get the Hurricane.

A problem here is trying to assign specific design attributes/characteristics to certain nations. Like having a specific requirement or directive from the the government (customer)
and not having 2-3 companies come up with similar solutions.
Things like (from Wiki)
In early May 1934, despite Germany being under a prohibition from the development of new military aircraft, the Reichsluftfahrtministerium (RLM) issued a request for a new single-seat monoplane fighter under the guise that the proposal was for creating a new 'sports plane'.[2] The Technisches Amt outlined specifications, for the supply of a new fighter aircraft, those submissions for the competition had to meet certain characteristics, including; a) having an all-metal construction, b) having a monoplane configuration, c) having retractable landing gear, d) be capable of achieving a top speed of at least 400 km/h (250 mph) at an altitude of 6,000 m (20,000 ft), e) endure ninety minutes at full throttle at 6,000 m (20,000 ft) f) reach an altitude of 6,000 m (20,000 ft) in seven minutes and have a service ceiling of 10,000 m (33,000 ft) g) be able to be fitted with a Junkers Jumo 210 engine h) be armed with either two 7.92mm fixed machine guns or one 20mm cannon and i) have a wing loading of less than 100 kg/m2. (20.48lb/sq/ft)

The He 112 started with a nearly 250sq ft wing. The 109 was almost 20% high on the desired wing loading. The higher speed of the of the 109 wound up beating the wing loading requirement. The 112 had about 1 meter clipped from the wings but it wasn't enough and the 112B (substernal revisions) would up with a 182sq ft wing.
Both companies had a problem in that they were limited to Jumo 210 engine of approximately 700hp.

The Russians were ham-strung by their engines. They wanted to replace the M-105 engine but the M-106 and M-107 were very late, very troublesome and basically didn't come into service during WW II (4-5 years late). La-5 was not designed to take full advantage of the M-82 engine. It was designed to be quick fix (more power) for an existing/in production airframe.
7000lb aircraft for 1100-1300hp engines are not light weight. Wooden airframes are not light weight for their size. If you are building out of wood (generally) you try to keep the airframe small to keep the weight low. And you limit the amount of fuel AND you limit the weight of guns/ammo. Soviets were never happy with the installed armament of their fighters. They always wanted more but they didn't want to sacrifice the speed/climb/turning that adding more guns would cost. Let's not confuse things by bringing in the Yak-3. a late 1944 fighter.

The engineers of the time had a good idea of what they had to do. Sometimes the customers did not, or they were trying to push things beyond current state of the art. Sometimes they wanted to see what the trade-offs were.
French, Germans, Italians, Soviets all had similar requirements as to range and speed and armament (fighting each other) and would up with similar fighters at the start. France vanished. Italy dropped out 1/2 through and didn't have a high powered engine. German late war stuff was pretty much vaporware (190Ds excepted?)

 

[Shortround6]

However, the Heinkel He112, which also falls into this group, had a wingspan of 37 feet, 9 inches with a wing area of 250 sq/ft, so it comes down to the design theory of that point in time, to be honest.

The 112 used 3 different wings which points out some of the problem. With a 700hp engine you can only shove a 235-250sqft wing through the air so fast. With a limit on the power how do you cut drag to get the speed you want? As pointed out above, they cut the wing area to 182sq ft and the wingspan to 29ft 10in.
The desired speed wound up being far in excess of the 1934 requirement.

What I don't know is if the desired wing loading in 1934 requirement had to do with turning/maneuver ability or with take-off/landing performance.

 

[GregP]

There were almost no large aerodromes in Europe at the time. Most wartime fields were basically a farmer's field.

I have heard the requirements were basically for short takeoff and landing distances from more than one German source.

 

[Shortround6]

Talk of "what did those colonials know" is beneath your normal level of discussion, the British had to make their own props for their own aircraft.

Better prop designs were out there. They existed well before 1940.
Rotol was formed because Fedden (Bristol) and RR knew the Air Ministry was dragging their feet and that DH (HS license) would not be able to supply the needed amount of propellers for the increased aircraft production. DH had signed the contracts in 1934, DH propellers was formed as a separate division in 1935.
Fedden was building his (Bristol) engines with oil lines/connections for possible variable pitch propellers. Bristol was building engines for other customers than just the British government.
I don't know what RR was doing as far as hydraulic fittings went. We know about the different prop shafts.

To me the whole story of the June-July emergency retrofit campaign for the DH propellers just shows that the air ministry had been sitting on their thumbs for 1938-39-40 when it came to propellers. All credit to those who came up with plan, implemented it and worked like hell through long nights to get it done.
But the planes should have been going out the door of the factories in 1939 with the better propeller set ups. They left the factories with 2/3rds of the set up. The adjustable hubs and pumps to control them (and the controls in the cockpit), What they did not have was the governor to control the pitch automatically. HS had been selling props with the governor since 1935.
This is a bit like going to the car dealer and telling them you don't want the 4 speed transmission car. You want a two speed car to save money on the purchase price. Just take a few cogs out and leave them on the bench and refund the difference in price.

In the early 30s there was problem with some of the British aviation press, like C. G. Grey (editor of Jane's all the Worlds Aircraft for one thing) that was rather dismissive of American aviation achievements or trends. Like referring to the early US monoplane bombers like the YB-9

as a fad and that the Americans would soon return to proper biplane bombers. Granted the B-9 was not that far ahead of the biplanes but history soon showed that patriotism does not beat aerodynamics (biplanes do NOT climb better than monoplanes).

Lets also not confuse cause and effect. British BoB fighters had best superchargers on any engine at the time. The Merlin even the pre Hooker supercharger gave better altitude performance than another engine.

I am not trying to argue over whole patents were better. I am arguing that the Air Ministry dropped the ball (and kicked it into the weeds) on the propeller issue during the late 30s and it cost the lives of many airmen during a large part of the war.
There wasn't enough production capacity but who's fault was that?
If you don't order enough propellers soon enough nobody is going to build/equip factories and have them sit idle while the propeller orders go to the wood carvers.

 

[tomo pauk]

I wonder how great the benefits really were when Allied designer wouldn't follow this design philosophy. High wing load means, longer take-off strips, higher landing speed and often more difficult handling especially for novice pilots. Add to this a worse turn radius.

A lot of taking off and landing problems to the novices can be solved by 'proper' training. The proper training cannot make the aircraft go faster, however.

Allied designers have had other sets of pre-requisites. Like the low stall speed in order to have good short-field abilities (had a lot to do with how Spitfire and Hurricane were designed, as well as why the biplanes were favored by RAF, also a reason why Beverly Shenstone found the job at Supermarine despite his 1st try was at Hawkers; similar requirements were for the carrier-borne fighters, thus we have eg. the big-wing Wildcat). Or the desire to install a combination of a big and heavy engine (18 cyl radial, or a 24 cyl liquid cooled engine), coupled with the fuel tankage required and firepower wanted - neither P-47 nor Typhoon were with the small wing loading.

We know that Bf 109 won the contest for the new fighter despite the wing loading being much higher than specified. If the 109 was disqualified on technicality, and the big-wing (also a thick-wing) He 112 won, the resulting fighter would've been worse than Gladiator or a I-16, and no better than the Hurricane I once DB 601A is in the nose.

Better turn radius < higher speed. Better turn radius cannot catch a speedy bomber, but having a higher speed surely helps.

 

[spicmart]

Messerschmitt was crazy for high wing loading which would transform to higher speed.
At least Focke Wulf put emphasis on roll rate additionally.
Interestingly the German philosophy, seemed to prefer roll over turning ability.
Pilots accounts appreciate that the "wings were small enough to guarantee good roll agility".

S Shortround6 Though they were wooden the first modern fighters were very light nevertheless. Where did they save so much weight?
Was there a design which could make full advantage of the M82, the La-9?
And why counting the Yak-3 out?

 

[tomo pauk]

Messerschmitt was crazy for high wing loading which would transform to higher speed.
At least Focke Wulf put emphasis on roll rate additionally.
Interestingly the German philosophy, seemed to prefer roll over turning ability.
Pilots accounts appreciate that the "wings were small enough to guarantee good roll agility".

Prof. Willy has probably forgotten that when designing the Bf 110?
Kurt Tank was even crazier wrt. the emphasis on high wing loading, despite what he says post-war. The future Fw 190 was designed as sround a smaller wing than what 'Jumo Bf 109' had, while having the engine being some 80% heavier, and with double the fuel tankage.
Heinkel was a convert to the church of small wing (high wing loading) after they lost with the He 112, and until the war's end.

The Italian fighter that Allies noted the best was the MC.202, again a fighter with a small wing. Nobody was talking with appreciation about the big Re.2001.

 

[Mike Williams]

To me the whole story of the June-July emergency retrofit campaign for the DH propellers just shows that the air ministry had been sitting on their thumbs for 1938-39-40 when it came to propellers. All credit to those who came up with plan, implemented it and worked like hell through long nights to get it done.

I am arguing that the Air Ministry dropped the ball (and kicked it into the weeds) on the propeller issue during the late 30s and it cost the lives of many airmen during a large part of the war.

I think you overstate your case.

151 Sqdn. Operations Record Book, 14 April 1940: "Hurricane R3310 with Rotol Airscrew flown from No. 20 M.U. at Aston Down by F/O. Newton."
1 Sqdn. Operations Record Book, 18 April 1940: "A new Hurricane was delivered to the Squadron, equipped with a constant speed airscrew and was flown by the C.O. and other pilots, all of whom were greatly pleased with it's superior performance.

1 Sqdn. Operations Record Book, 2 May 1940: "Five machines flew to Amiens and four were exchanged for the new constant speed airscrew Hurricanes."

F/O Paul Richey, 1 Squadron, 15 May 1940 France: "I was flying a new aeroplane with a Rotol constant-speed prop..."
F/Lt I. R. Gleed, 87 Squadron, 19 May 1940 Rotol constant-speed airscrew used in France. W/C Ian Gleed D.F.C., Arise to Conquer, (Random House, New York 1942) pp. 62-63.
Paul Richey DFC, Fighter Pilot (Redwood Press, Wiltshire 1990) p 93.
151 Sqdn. Operations Record Book, 15 May 1940: "The squadron can now put up 12 Rotol Hurricanes if required."

32 Squadron, 19 May 1940: "No. 32 (F) Squadron, based at Biggin Hill and flying Hurricanes with Rotol propellers, went into action on 19th May over Cambrai" Francis K. Mason, The Hawker Hurricane, (Doubleday, New York 1962) p 48.
229 Squadron Operations Record Book, 23 May 1940: "Rotol Hurricane"
213 Squadron Operations Record Book, 25 May 1940<: "Rotol Airscrews"
Conversion of Hurricane Aircraft D.H. Two-Pitch Airscrews to Constant Speed.
79 Squadron Operations Record Book, 9 June 1940: "Rotol airscrew"
242 Squadron, June 1940: "Rotol constant speed propellers had been fitted to the Hurricanes in early June, replacing the two-position propellers of earlier models." Hugh Halliday, No. 242 Squadron, The Canadian Years, (Canada's Wings, Ontario, 1981). p.78.
P/O T. F. Neil, 249 Squadron, June 1940: "It had a constant-speed Rotol propeller..." Wing Commander Tom Neil, DFC, AFC, AE, Gun Button to 'Fire', (William Kimber, London 1987), pg 48.
June 1940 - one of 249's first Hurricanes, with metal wings and Rotol airscrew
The Latest Rotol Airscrew, Flight, May 23,1940

Assistant Chief of the Air Staff, 100 octane approval for Spitfire Squadrons, 24th September 1938
19 Squadron Operations Record Book, November 1939, Delivery of Rotol Constant Speed propeller equipped Spitfire
No 54 Squadron Operations Record Book. December 1939. "The squadron commenced to re-equipped with Rotol Spitfires."
Spitfire I fitted with De Havilland Constant Speed Airscrew, 22.6.40

Check out what props 109E's were using during the BoB
RM 2361
Steinhilper

 

[spicmart]

Prof. Willy has probably forgotten that when designing the Bf 110?
Kurt Tank was even crazier wrt. the emphasis on high wing loading, despite what he says post-war. The future Fw 190 was designed as sround a smaller wing than what 'Jumo Bf 109' had, while having the engine being some 80% heavier, and with double the fuel tankage.
Heinkel was a convert to the church of small wing (high wing loading) after they lost with the He 112, and until the war's end.

The Italian fighter that Allies noted the best was the MC.202, again a fighter with a small wing. Nobody was talking with appreciation about the big Re.2001.

Fair enough ,you're right about Tank.
One has to grant him that he put importance to agility around the longitudinal axis though.
Afaik it was the Fw 190 which brought this aspect of air combat really to prominence.
Please correct me if I'm wrong.

As far as the Italians were concerned, what about the Fiat G.55?
Allegedly touted by Tank "as the best of the Axis", where I doubt whether there was ever something quotable in that line.

 

[tomo pauk]

Fair enough ,you're right about Tank.
One has to grant him that he put importance to agility around the longitudinal axis though.
Afaik it was the Fw 190 which brought this aspect of air combat really to prominence.
Please correct me if I'm wrong.

Aircraft that were able to roll well were well regarded even during the ww1.

As far as the Italians were concerned, what about the Fiat G.55?
Allegedly touted by Tank "as the best of the Axis", where I doubt whether there was ever something quotable in that line.

MC.202 was the one to beat, especially for the pilots on Hurricane or P.40, it was with a relatively good timing, and it was manufactured in good numbers as far as the Italian war production goes.
G.55 was manufactured in very small numbers, by the time Allies have had the better performing A/C in service than the G.55 was. It would've been the wonder if Allies were impressed by it.

 

[Greg Boeser]

I think you overstate your case.

151 Sqdn. Operations Record Book, 14 April 1940: "Hurricane R3310 with Rotol Airscrew flown from No. 20 M.U. at Aston Down by F/O. Newton."
1 Sqdn. Operations Record Book, 18 April 1940: "A new Hurricane was delivered to the Squadron, equipped with a constant speed airscrew and was flown by the C.O. and other pilots, all of whom were greatly pleased with it's superior performance.
View attachment 771906
1 Sqdn. Operations Record Book, 2 May 1940: "Five machines flew to Amiens and four were exchanged for the new constant speed airscrew Hurricanes."
View attachment 771907
F/O Paul Richey, 1 Squadron, 15 May 1940 France: "I was flying a new aeroplane with a Rotol constant-speed prop..."
F/Lt I. R. Gleed, 87 Squadron, 19 May 1940 Rotol constant-speed airscrew used in France. W/C Ian Gleed D.F.C., Arise to Conquer, (Random House, New York 1942) pp. 62-63.
Paul Richey DFC, Fighter Pilot (Redwood Press, Wiltshire 1990) p 93.
151 Sqdn. Operations Record Book, 15 May 1940: "The squadron can now put up 12 Rotol Hurricanes if required."
View attachment 771908
32 Squadron, 19 May 1940: "No. 32 (F) Squadron, based at Biggin Hill and flying Hurricanes with Rotol propellers, went into action on 19th May over Cambrai" Francis K. Mason, The Hawker Hurricane, (Doubleday, New York 1962) p 48.
229 Squadron Operations Record Book, 23 May 1940: "Rotol Hurricane"
213 Squadron Operations Record Book, 25 May 1940<: "Rotol Airscrews"
Conversion of Hurricane Aircraft D.H. Two-Pitch Airscrews to Constant Speed.
79 Squadron Operations Record Book, 9 June 1940: "Rotol airscrew"
242 Squadron, June 1940: "Rotol constant speed propellers had been fitted to the Hurricanes in early June, replacing the two-position propellers of earlier models." Hugh Halliday, No. 242 Squadron, The Canadian Years, (Canada's Wings, Ontario, 1981). p.78.
P/O T. F. Neil, 249 Squadron, June 1940: "It had a constant-speed Rotol propeller..." Wing Commander Tom Neil, DFC, AFC, AE, Gun Button to 'Fire', (William Kimber, London 1987), pg 48.
June 1940 - one of 249's first Hurricanes, with metal wings and Rotol airscrew
The Latest Rotol Airscrew, Flight, May 23,1940

Assistant Chief of the Air Staff, 100 octane approval for Spitfire Squadrons, 24th September 1938
19 Squadron Operations Record Book, November 1939, Delivery of Rotol Constant Speed propeller equipped Spitfire
No 54 Squadron Operations Record Book. December 1939. "The squadron commenced to re-equipped with Rotol Spitfires."
Spitfire I fitted with De Havilland Constant Speed Airscrew, 22.6.40

Check out what props 109E's were using during the BoB
RM 2361
Steinhilper

Regarding the German variable pitch prop, an experienced pilot could get excellent performance, novices - not so much.

 

[Geoffrey Sinclair]

The generic story is the pre/early war RAF fitted constant speed propellers to its bombers before the fighters. According to the Ministry of Aircraft Production De Havilland Stag Lane built around 2,225 propellers in the second half of 1939 and 4,833 in 1940, Lostock built around 3,275 in the second half of 1939 and 9,407 in 1940. Rotol built 1,584 in 1939 (around 1,150 in the second half of the year) and 4,962 in 1940, Fairey built 2,744 in 1939 and 3,842 in 1940, the Airscrew Company built 7,785 in 1939 and 8,640 in 1940.

According to the RAF contract card and serial register notes Hurricane L1909 was the first Merlin III in April 1939, L1980 was the first two pitch propeller in June 1939. L1877 in March 1939 was the first with metal wings but was for development, L2026 had a Rotol propeller and metal wings, again for development with L2027 in mid July the next marked metal wings, it went to Turkey, there seems to have been a gradual change over with N2426 the last Brooklands production aircraft with fabric wings, apart from a batch delivered in mid 1940, N2426 delivered 14 November 1939. It appears all Langley and Gloster production were fitted with metal wings. Langley first production was N2318 to N2337.

The change over to constant speed propellers was during the third contract which was split between Brooklands (292 a/c), Langley (232 a/c) (P3265 to P3984 (500 a/c), P8809 to P8818 (10 a/c), R2680 to R2689 (10 a/c), W6667 to W6670 (4 a/c)) and Gloster (500 a/c P2535 to P3264)

Gloster: P2682 (101st built) onwards fitted with Rotol, first such aircraft delivered on 27 February 1940. (TR1133 fitted from P2681)

Hawker: P3265 onwards fitted with Rotol except 15 to be fitted with DH two pitch, similar to 35 modified to tropical standards by Hawkers at MU. The Rotol fitted aircraft began being delivered on 22 February 1940. There is the usual uncertain area, Langley built N2453 to N2501, N2592 to N2631, N2645 to N2654 before its first P serial P3400. N2500 and N2501 were delivered late February, while most from N2592 on were delivered late February to early April, these may have had Rotol propellers, but strangely enough 15 of the Langley Hurricanes were sent to the Middle East July/August 1940.

As an example of delivery dates N2502 from Langley was delivered on 29 February 1940, N2503 to 2519 were a Blackout Block, N2520 from Brooklands was delivered on 3 December 1939.

The RAF Contract cards say 174 Spitfires from the first order had Merlin II, to K9960, which would mean a change over in May 1939, the AM78 aircraft cards say the first 194 had Merlin II, to K9979 in June. So no Rotols on production types before mid 1939. The following N serials are marked in the contract cards with the comment Rotol Airscrew

N3030 (probably flying in mid September 1939 but delivered 5 October)
October 1939, N3096, N3097 (Contract B10783/39 or B10983/39 versus the production contract 527113/36), N3103, N3104, N3110, N3111
November N3122, N3124, N3130, N3160, N3171 to N3174, N3176, N3180, N3183, N3185, N3187, N3188
December N3184.

Total 22, no more marked. Unlike the Hurricane Contract Cards there is no comment about when Rotol became standard and it looks like there was a special order made in 1939 to build roughly a squadron's worth of Spitfires. Reported followed by another 10 R serials with official delivery dates between 19 and 25 July 1940, these are not noted as having Rotol propellers in the Contract Cards but see the dates below. Used by 54 squadron from December 1939.

Rotol was the standard fit for the Spitfire II, production starting in June 1940.

According to The Defiant File by Alec Brew constant speed propellers were fitted from the 88th production Defiant (first aircraft of second order) N1535 delivered mid June 1940.

The Fulmar I started production in April 1940, no confirmation in whether it was with a constant speed propeller but it appears so.

So the constant speed propeller change over early in the Battle of Britain was mostly Spitfires being converted from two pitch to constant speed DH, as the Hurricanes built since late February were using Rotol, though there were still plenty of legacy Hurricanes, official production April 1939 to February 1940 inclusive was 651, less losses and exports by mid 1940. Total Hurricane production to end June 1940 was 1,815.

Spitfire Biography AVIA 46/119

16 June 1940 Letter from Fighter Command saying that Spitfires with Rotol constant speed airscrews have the following advantages - Better take off, climb, ceiling, manoeuvrability, diving speed and endurance. The Rotol Spitfire is superior to any enemy aircraft yet encountered from Hornchurch. It is requested that constant speed airscrews shall be fitted to production aircraft as a matter of urgency [54 Squadron moved back and forth between Hornchurch and Rochford October 1939 to August 1940]

17 June 1940 Spitfire I modified to take De Havilland Constant Speed Unit is equal in performance to Rotol Constant Speed Airscrew and superior to De Havilland 2 pitch. The conversion from 2 pitch to constant speed takes approximately 20 man hours. Requests for immediate retrospective conversion of all 2 pitch airscrews in Spitfires.

22 June 1940 R.D.T.3 reports to D. of O. that Spitfire Is are being converted from De Havilland 2 pitch to De Havilland Constant Speed airscrews by De Havilland's working party on a very urgent priority. A number have already been converted.

1 July 1940 R.T.O at Supermarine informed of fitting to production Spitfire I's of constant speed units. The change of policy was made in a somewhat irregular manner for the R.T.O had first received this information through the R.T.O. at De Havilland's. Official confirmation has only been given recently.

From Paul Lucas,

"According to 'Rotol The History of an Airscrew Company 1937-1960' by Bruce Stait, Alan Sutton Publishing Ltd 1990'.
All the following are listed as 'No 5 non-standardised external cylinder with 35° range'.
RX5/1 Spitfire II Merlin XII General Arrangement (GA) Drawing No. Rotol Airscrews (RA) 3127, Blade RA640.
RX5/2 Hurricane I Merlin III GA RA3128, Blade DR (Weybridge) 291.
RX5/3 Spitfire II Merlin III GA RA3127, Blade RA675.
RX5/4 Spitfire I Merlin III GA RA3127, Blade RA640.
RX5/5 Hurricane I Merlin III GA RA5653, Blade RA4067.
RX5/6 Whitley V Merlin X GA RA8610 Blade RA4060(Dural).
RX5/7 Fulmar II Merlin XXX GA RA8799, Blade DR531.
RX5/8 Fulmar II Merlin XXX GA RA9663, Blade RA4065.
RX5/9 Fulmar I Merlin VIII GA RA8799 Blade DR531.
RX5/10 Spitfire V Merlin 45 GA RA9186, Blade RA690.
RX5/11 Barracuda I GA RA10534, Blade DS 940.
RX5/12 Hurricane II Merlin XX GA RA10534, Blade DS940.
Blades with a 'D' prefix were a Weybridge type.
This information seems to have been drawn from Rotol's Drawing Stores. Make of it what you will.

Prior to the 'RX' series there was a 'R5' series listed as being "No.5 size external cylinder propeller with 20° Range."
Both the Whitley IV, Merlin IV and Whitley V, Merlin X had the same GA RA570 and Blade RA4042 Type Numbers.
Both the Fulmar I, Merlin VIII and Fulmar II, Merlin XXX also had the same GA RA570 and Blade DB191A type numbers."

When it comes to training the less time required to master a type the better, no idea what RL III 944 defines as a not enemy action loss but it says September to December 1943 for the fighter units there were 619 Bf109 lost in combat and 443 to non combat reasons, 266 Fw190 in combat and 145 non combat.

I note RL II 930 has JG and ZG combat losses in the west as 141, 207, 167, 167 September to December 1943, a count from unit records comes up with monthly figures of 182, 226, 158, 181.

 

[Shortround6]

A lot of taking off and landing problems to the novices can be solved by 'proper' training. The proper training cannot make the aircraft go faster, however.

Proper training also cannot make the plane take-off in a much shorter distance. For the Hurricane the distance from "wheels up" to the 50ft limit was remarkably similar between the different propellers, only about a 30yd difference. The big difference was in the 130 yd difference in the ground run. Accelerating from standing start to flying speed.
These are using zero flaps so there is some room for improvement but you are going to get some improvement for all three propeller types.

 

[Shortround6]

Though they were wooden the first modern fighters were very light nevertheless. Where did they save so much weight?
Was there a design which could make full advantage of the M82, the La-9?

I think we are confusing design philosophies (what they wanted to happen) with actual results (What did happen).
The prototype Lagg (I-301) of 1940 was 5462lbs empty and 6,543lbs loaded.
The Prototype Yak (I-26) of 1940 was 5,110lbs empty and 5,962lbs loaded (?). Only 850lbs of fuel, pilot, guns, etc?

The Hurricane prototype of 1936 was 5672lbs loaded, Ballast instead of guns/ammo.
The Spitfire prototype of 1936 was 5332lbs loaded, Guns?

What happened was that they all gained weight, armor fuel tank protection, better/more radios (or any radios for some of the Soviet planes.) more armament and so on.
But a lot the later improvements were not part of the original design philosophy. They were what could be done with existing designs (and manufacturing plant) to adapt to new conditions.

And why counting the Yak-3 out?

Because it was late comer, very late. Not as late as the Grumman F8F but closer to the F8F than to most other WW II planes.
There were also changes in armament (early batches had one 20mm gun and one 12.7mm MG) and there were quality issues. about 800 of the late 1944 production were withdrawn from service and sent for repair. Having the wing skins depart in flight was not a good thing.
They got it straighten out but using the Yak-3 as an "example" of soviet design philosophy from the late 30s to around 1942/43 is misleading.
They were 'stuck' with the M-105PF-2 engine and the two gun armament and small wing were the result of trying to get the most performance out of the engine and armament.
Having an average mission length of about 40 minutes worked for the Soviets but comparing that to what other countries were doing (or needed) is not comparing like to like.

 

[MikeMeech]

Hi

'The Spitfire Story' by Alfred Price contains details of tests with different props:

The DH staff who were converting the DH two-pitch to CS were dealing with the Spitfires and Hurricanes that had been delivered before the end of 1939, deliveries of Rotol CS had started before the end of that year (October 1939 for the Hurricane) so they did not need any conversion.
Bombers and other large aircraft had the priority for both VP and CS props to give that better TO performance so they could use airfields that had already been built as well as the larger ones that were building during the second half of the 1930s. From 1936 onwards the larger types of aircraft were fitted with VP and later CS props, these were large orders, for example in July 1936 the initial order for Blenheim Is was for 150 aircraft quickly followed by an additional 434 all equipped with two-pitch props (even the 100 HP Harrow stop-gap bombers had two-pitch props). We should remember that these were very large orders in comparison with the first half of the 1930s and the aircraft industry (and government) had to expand both factory space and train an ever increasing workforce (without bankrupting the country). For example on 3 June 1936 the first order for Hurricanes was for 600 aircraft, in comparison the USAAC on the 7 July 1937 made their largest aircraft order since WW1, this was for 210 P-36 aircraft, this does indicate the different scale that the British industry was working on in this period. Of course not every aircraft was going to get the 'best' propellers at the same time, but production had to start and updates added later.

Mike

 

[Shortround6]

From 1936 onwards the larger types of aircraft were fitted with VP and later CS props, these were large orders, for example in July 1936 the initial order for Blenheim Is was for 150 aircraft quickly followed by an additional 434 all equipped with two-pitch props (even the 100 HP Harrow stop-gap bombers had two-pitch props). We should remember that these were very large orders in comparison with the first half of the 1930s and the aircraft industry (and government) had to expand both factory space and train an ever increasing workforce (without bankrupting the country). For example on 3 June 1936 the first order for Hurricanes was for 600 aircraft, in comparison the USAAC on the 7 July 1937 made their largest aircraft order since WW1, this was for 210 P-36 aircraft, this does indicate the different scale that the British industry was working on in this period. Of course not every aircraft was going to get the 'best' propellers at the same time, but production had to start and updates added later.

This is over a year after HS announces the constant speed propeller and about 2 years after DH signs the license agreement for the two pitch prop.
Credit is due to DH for seeing the potential and getting the license.
More Credit is due to Fedden and RR for seeing the shortfall and trying to do something about it.
Credit to the air ministry is lacking.

For the converted Spitfires we have the cost/labor of the pump/governor unit and the 20 hours of labor needed to install it an already built airplane sitting on an active fighter field.
One wonders what the hours of labor needed to install the parts would have been at the factory in the proper order with all the cowlings/covers not installed.
The CS version of the DH propeller could have been built in 1936. It would have been a bit more expensive but it required zero "new" knowledge (new license for governor?)

On the multi engine aircraft the British were late in adopting the fully feathering propeller which could add several thousand feet to the singe engine ceiling of a twin engine aircraft.

The US was far from perfect. Noted earlier was the use of a single electrical generator on the P-38 with it's electrically operated propellers. If the engine that went down was the one with the generator the ability to get home was not dependent on the amount of fuel but the state of the battery and the electric management skills of the pilot (periodically turning off the radio/s and instrument lights for instance).
Hudsons were a mixed bag, some had constant speed props (maybe some had 2 pitch?) later ones got the full feathering props which significantly increased survivability on long over water patrols.
and again, the fully feathering propellers were in use by 21 different airline companies before WW II started, granted some may have only had a handful of planes so production total was ???? The British were loosing some Beaufighters in 1941 (maybe later?) due to not having Fulling feathering propellers.

 

[Geoffrey Sinclair]

The DH staff who were converting the DH two-pitch to CS were dealing with the Spitfires and Hurricanes that had been delivered before the end of 1939, deliveries of Rotol CS had started before the end of that year (October 1939 for the Hurricane) so they did not need any conversion.

Which documents state the Rotols were being fitted in October 1939? The Contract Cards and Serial Registers are saying late February 1940 was the change over. The Spitfire I stayed with 2 pitch until mid 1940 except for a special order.

For example on 3 June 1936 the first order for Hurricanes was for 600 aircraft, in comparison the USAAC on the 7 July 1937 made their largest aircraft order since WW1, this was for 210 P-36 aircraft, this does indicate the different scale that the British industry was working on in this period. Of course not every aircraft was going to get the 'best' propellers at the same time, but production had to start and updates added later.

The US aviation industry was largely civilian based, using the CAA Statistical figures in 1935, 336 US military, 1,079 US civil, 333 exports, in 1936, 527 US military, 1,637 US civil, 527 exports. The British industry was much more military, I do not have good figures for civil and exports, in 1935 it was 893 RAF/RN, in 1936 2,005.

The Nazis were pushing the German aviation industry hard and so were able to keep up with the US numbers wise, US in 1937 3,778 aircraft, in 1938 3,623, in 1939 5,826. Similar for the British until 1939.

 

[tomo pauk]

The British were loosing some Beaufighters in 1941 (maybe later?) due to not having Fulling feathering propellers.

British were probably loosing much more aircraft due to the outdated fuel delivery system to the engine, that was still based on the float-type carbs, and thus being bad for the negative G maneuvers, as well as being susceptible to the icing. Or, due to the fuel tanks being leaky when punctured until well into the BoB.
But then, Germans lost even more aircraft due to the 109s not having the drop tank installations until the end of the BoB.

Just to put the things into a perspective.

 

[Shortround6]

The US aviation industry was largely civilian based, using the CAA Statistical figures in 1935, 336 US military, 1,079 US civil, 333 exports, in 1936, 527 US military, 1,637 US civil, 527 exports. The British industry was much more military, I do not have good figures for civil and exports, in 1935 it was 893 RAF/RN, in 1936 2,005.

The US numbers are somewhat deceptive. US civil aviation was huge but there was a very large difference between commercial aircraft ( and the US lead the world in those number wise) and private aviation (private or cooperate aircraft) and there was a blurry spot in-between with air taxis and flying school operators.

They built about 1200 of these in 3 years.

Taylor J-2 which was turned into the Piper J-3 in 1938 (?) There were a crapload of smaller competitors.
There were flying schools were 3-4 of these were the fleet and might be counted as "commercial" aircraft.
The US also had quite a number of 4-6 seat single engine aircraft with 200-450hp engines that numbered in the hundreds during the 30s and many of the larger engined models could be fitted with 2 pitch propellers, at least that was an option in 1936-37 and later.
Comparison to military aircraft gets sketchy. Granted few, if any, accounts make any finer distinctions.
A lot of the "exports" were the smaller aircraft. Smaller being the 4-6 seat aircraft in areas that could not support DC-3 type aircraft (not enough traffic).
However there was enough business to keep 3 companies (Continental, Lycoming and Jacobs) building 200-300hp radial engines and the big 2 (P&W and Wright) staying in the 300-450hp range.
However, these were flying in 1934

Some were rebuilds of 1933 aircraft. The new planes had rebuilds had 2 pitch props. Late ones had a choice of HS or Curtiss props.
They did not survive competition with monoplanes. around 9 went to China as bombers.
Top speed 181mph, cruise 160mph, max climb 1200fpm and it was supposed to fly at 4,000ft with one engine out (these props did NOT feather).
Single engine performance (or one engine out on 3-4 engine planes) was of considerable interest to US operators with the Allegheny Mountains in the east and Rockies in the west with many smaller mountain ranges. Granted bad weather and/or high temperatures could eliminate the hoped for margin but the 1920s and early 30s had seen enough crashes into high ground with the US Air Mail Service.
Please note that 4000ft on a 59 degree day will not get you more than a few miles into Colorado and forget getting any further west.

 

[Canaus]

Was the preference of German aircraft designers for small wings/high wing loading a virtue or a drawback for a fighter in combat?

The discussion about the wing loading of German fighters seems to have diverged into a discussion about propellers.

When one discusses German fighter high wing loading we must be talking about the Bf109. Surprisingly no mention has been made on the Handley Page leading edge slats on the 109 wing and their design to allow a smaller wing to be used.

basepage

When Willy was designing the 109 he went with the smallest frontal area and tightest smallest & lightest low drag package to fit the inline water cooled engine. A trade off was made to incorporate the leading edge slats to reduce the wing area while still allowing for a low enough landing speed. A smaller wing being lighter and with less drag with the benefit of a higher speed.

When one looks at the competition for the Luftwaffe fighter contract in 1935, two of the proposals, Arado Ar 80 & Focke-Wulf Fw 159, were still a transitional designs from the biplane era, although both were monoplanes. The Heinkel He 112 was too complex but the contract was not given to them due to previous bomber contracts. So the 109 won by default.

During the 109 production run much effort was made not to disrupt the production line so the wing did not appreciably change over production run.

When one looks at the comparison between the Spitfire and the 109 wings during the early phase of WW2 it's amazing that 2 dissimilar wings; wing area, wing loading, plan shape & wing tips could be so closely matched performance wise.

But as the war progressed the lack of wing area would have been a drawback to performance as the increase in dry weight increased due to increased armament & equipment. The 109s small and tight packaging of the complete aircraft certainly was a detriment in trying to find room for more fuel tanks.