Performance modifications done at Squadron level.

[Engineman]

Did they also debugged the 801D?

This was the 801 C according to Nowarra.

Eng

 

[NZTyphoon]

Interesting post. The video is good, but note that it is for the later licensed Hamilton-Standard Hydromatic type propeller, not the earlier licensed H-S "Bracket" type propeller that is referred to in the Flight written article.
The Flight article has some detail of some aspects of the De Haviland work, but nothing on Rotol. I think there is an error in the "more than 7,000' increase in ceiling" claim. The early Mk1 Spit with 2-bladed wooden prop was tested with a service ceiling of 31,900'. A similar 1939 Spit, 200lbs heavier, with the De-Havilland 2-pitch airscrew had 34,400' and a similar early 1940 one with Rotol 3-blade constant speed prop gave 34,700' ceiling. All these with same boost limits on 87 Octane fuel. So, we are seeing only about 2,500' increase in ceiling. However, the time to climb from zero to 30,000' was respectively, 22m25s, 23m04s and 16m24s, a very definite win for the C-S prop!
BTW, an indication of the further improvement that the 100 Octane fuel made with increased boost in the climb is that a similar climb to 30,000' was 13m42s, some 2m42s faster than the 87 oct performance. The bigger factor then, was the Constant Speed function, although the 100 oct was a further improvement.

Eng

Speaking of the Rotol propeller, here are a couple of articles from the Flight magazine archives: the 1939 article describes to origins and design of their first C/S units; the 1940 article describes the then latest 35 degree pitch propeller. (sadly, Flight ended their archiving service some years ago and have never bothered reinstating it.)

1940:

AFAIK, the first operational RAF fighters to be equipped with the Rotol C/S propellers were Spitfires of 54 Sqn, that started being equipped with them on 10 December 1939: these were from the second Nxxx production batch. The Rotol conversions were carried out by 6, 9, 24 and 27 MUs. The squadron was probably progressively re-equipped with de H propeller Spitfires from about late May 1940, as operations over Dunkirk took their toll.

From WWII Aircraft Performance, the first Rotol equipped Hurricanes possibly arrived on 151 Sqn in April 1940.
Interestingly, the Miles Master I advanced trainer was fitted as standard with a 720 hp Rolls-Royce Kestrel XXX, driving a Rotol C/S propeller.

 

[MIflyer]

Very interesting tidbits here! The whole issue of ailerons is underrated I think. It seems to have been a major issue with the early Mustangs as well as the Spits.

It is interesting to me just how much better the ailerons on US fighters worked as compared to others.

 

[Admiral Beez]

I'm reminded of how the RAF and RAAF fitters removed guns and parts from their Buffalos to improve power to weight ratios.

 

[Steamed_Banana]

It is interesting to me just how much better the ailerons on US fighters worked as compared to others.

Not on those early Mustangs

 

[Geoffrey Sinclair]

In fact, the Mk VIIs were given the prefix F. or HF., depending on the model of Merlin engine that was fitted. Similarly, the Mk. VIIIs could be F., HF. or LF.

Not sure about the F.VII was Merlin 64 the HF.VII was Merlin 71. Using the Spitfire Histories site, Spitfire VII 1 M45 (prototype, became M61), 21 M61 and 118 M64, total 140. The Ministry of Aircraft Production says 16 Merlin 71c built July and August 1944, mark VII production had ended in May 1944. Some of the PR.X 16 mark X built April/May 1944 are reported to have used M71.

The LF. Mk. VIII was the first Spitfire to use the Merlin 66, starting with JF462 in May 1943; from JF744 on (built in late June '43), the Merlin 66 was the predominant engine.

The production reports record Supermarine building 40 LF.IX February to June 1943 in parallel to the final F.IX production, Castle Bromwich 1 LF.IX in April 1943, not sure about the serial, another in June.

The F to LF.VIII change over was May to September 1943 plus a final 20 F.VIII in November

By comparison, the first Merlin 66 LF. MK IX, MH350, was built in August 1943, with production hitting full stride, starting with MH384 on August 8 '43.

Castle Bromwich change over from F to LF.IX was August to October 1943.

March 1943 production report, entries for F.Vc, F.VII, F.VIII, F.IX, F.XII, F.XII. The reports classified the March/April LF.IX as F.IX before correcting it in April.

The April production report has entries for F.Vc, F and HF.VII, F and LF.VIII, F and LF.IX, PR.XI and F.XII but no HF.VII or LF.VIII produced.

May as per April but this time LF.VIII were produced.

June drops the HF.VII entry, it does not reappear. Cumulative production to end June put at 33 F.VII, 223 F.VIII, 25 LF.VIII, 875 F.IX, 47 LF.IX, including 7 from Castle Bromwich, which is an over count and later corrected. The LF.IX versions were a slight surprise to the system.

Article in message 41

Production to end June 1940, 109 Defiant, 836 Spitfire I, 10 Spitfire II, 1,815 Hurricane I

Hurricane L1980 (434th built), first variable pitch propeller, constant speed units fitted from end February 1940, giving 433 two pitch, around 520 two pitch and around 830 constant speed by end June 1940. Hurricanes for overseas service kept being fitted with the 2 pitch propellers. The first 363 Hurricanes had the Merlin II, which in theory precluded fitting the later propellers.

The first 194 Spitfire had Merlin II, there was also a test batch of constant speed Spitfire I in 1939, plus replacements in mid 1940, otherwise the idea was the mark II to have a constant speed propeller, mark I 2 pitch.

First 87 Defiant fitted with 2 pitch propeller.

Compared with the article numbers of two pitch propeller production to end June as around 1,250 Hurricane, 1,000 Spitfire, 325 Defiant. It is interesting the article only mentions Spitfire conversions.

RAF Performance charts climb to 15,000 feet, Spitfire I, unknown propeller, 87 Octane, 6.2 minutes, Spitfire II, 100 Octane, 4.9 minutes, Hurricane I, 87 Octane, DH 2 pitch 7.25 minutes, Rotol constant speed 6.3 minutes.

 

[MikeMeech]

From WWII Aircraft Performance, the first Rotol equipped Hurricanes possibly arrived on 151 Sqn in April 1940.
Interestingly, the Miles Master I advanced trainer was fitted as standard with a 720 hp Rolls-Royce Kestrel XXX, driving a Rotol C/S propeller.

Hi
The Air Ministry Specification, 16/38, that the Miles Master I fulfilled called for "A constant speed airscrew of a type to be agreed by DTD shall be fitted..." (see page 261 of 'The British Aircraft Specifications File' by Air-Britain). This resulted in the Master I entering service just before the outbreak of war fitted with the Rotol CS on its reconditioned Kestrel engines. It can be assumed this was an official policy to train pilots on systems they would be using on operational aircraft in future. Priority for CS airscrews on operational aircraft appear to have been bombers (or other large aircraft) in the pre-war period, probably due improved take-off performance.

Mike

 

[bada]

When?

Being at work, can't post from a book, but this information is rather well known and repeated in most books about the Wurger, it's even on wikipedia (not that is a good thing, but for once, the info is correct )

"The introduction of the BMW 801 C-2 resulted in the Fw 190 A-2 model, first introduced in October 1941. As part of this upgrade, a modification to the exhaust system devised by III./JG 26's Technical Officer ("T.O.") Rolf Schrödeter was added. There were 13 exhausts for the 14 cylinders; eight of these were grouped to exit, four on each side, along the forward fuselage, just above the leading edge of the wing; under the forward center section, between the undercarriage bays were five exhaust stacks, with cylinders 9 and 10 sharing a common pipe.[12]​ To quickly implement the fix, it was found that the re-routing could be done easily in Gruppe workshops. The reduction in temperature affecting the bottom cylinder went a long way to solving the problem.[13]​[14]​ The addition of new ventilation slots on the side of the fuselage further aided cooling, and with the widespread availability of the A-2 in the spring of 1942, the overheating problems were greatly reduced."

 

[tomo pauk]

The introduction of the BMW 801 C-2 resulted in the Fw 190 A-2 model, first introduced in October 1941. As part of this upgrade, a modification to the exhaust system devised by III./JG 26's Technical Officer ("T.O.") Rolf Schrödeter was added. There were 13 exhausts for the 14 cylinders; eight of these were grouped to exit, four on each side, along the forward fuselage, just above the leading edge of the wing; under the forward center section, between the undercarriage bays were five exhaust stacks, with cylinders 9 and 10 sharing a common pipe.[12] To quickly implement the fix, it was found that the re-routing could be done easily in Gruppe workshops. The reduction in temperature affecting the bottom cylinder went a long way to solving the problem

Many thanks.
Unfortunately, the actual fix seems not to be described.

The addition of new ventilation slots on the side of the fuselage further aided cooling, and with the widespread availability of the A-2 in the spring of 1942, the overheating problems were greatly reduced.

Was this a factory mod, or a field mod?

 

[MIflyer]

Not on those early Mustangs

True, but that is why NAA and Farnboro were working to improve them.

 

[MIflyer]

I'm reminded of how the RAF and RAAF fitters removed guns and parts from their Buffalos to improve power to weight ratios.

And I am reminded how the RAF and RAAF installed bulletproof windshields.

 

[Admiral Beez]

And I am reminded how the RAF and RAAF installed bulletproof windshields.

I see it I think on this Buffalo below, and certainly absent on the USN version.

If the bulletproof windshields weren't included with the aircraft as delivered, how did they get those sourced or made in Malaya? Bulletproof windshields need some serious laminated and ballistic glass fabrication capabilities.

 

[Steamed_Banana]

I thought they were sent as applique kits

 

[ssnider]

The Netherlands B339s had armored windschields

 

[Admiral Beez]

I thought they were sent as applique kits

It doesn't appear to be fitted when unboxed. So perhaps it is an added kit later.

 

[Steamed_Banana]

Isn't that what was happening with the Spitfire Mk Vs initially?

 

[MIflyer]

Interesting thing about adding armor. My friend Bob Berry flew on USN PB4Y-2 in VPB-109. They REMOVED some of the armor that had been installed in the airplane because when rounds came in, the effect was like a pinball machine, rattling around inside the airplane after hitting the armor instead of just passing through. This was especially important given the Japanese preference for head on attacks, aiming at the cockpit.

On the mission where his airplane and another were attacked by twelve George II fighters, the man who was wounded the worst was another radioman seated across the cockpit from Bob, when on a head on pass an explosive round detonated on the inside of the armored seat back and exploded. The result was a shotgun-like blast of shrapnel that tore up the crewman's back. Had the seat back not been armored the round would have went right through and then on out of the airplane.

 

[tomo pauk]

On the mission where his airplane and another were attacked by twelve George II fighters, the man who was wounded the worst was another radioman seated across the cockpit from Bob, when on a head on pass an explosive round detonated on the inside of the armored seat back and exploded. The result was a shotgun-like blast of shrapnel that tore up the crewman's back. Had the seat back not been armored the round would have went right through and then on out of the airplane.

Were the Japanese 20mm shells that bad, so they weren't exploding when hitting the stressed skin or other metal in an aircraft?

 

[MIflyer]

Isn't that what was happening with the Spitfire Mk Vs initially?

Note the externally applied armored glass on this Spit. The ARII/OTAKI Spit V kit even comes with two windshields, one with external armor glass and one without.

 

[MIflyer]

Were the Japanese 20mm shells that bad, so they weren't exploding when hitting the stressed skin or other metal in an aircraft?

I don't know if that was even 20MM. You would think so, given that the George has four 20MM. And in any case I think you'd rather the shells penetrate and explore and do more damage.

Hitting the aircraft skin might not even be fatal damage.