100-octane fuel in the RAF in 1940 (4 Viewers)

[Mike Williams]

More comparison data here:

Comparisons of Spitfire I's with DH and Rotol props and bullet proof windscreen found top speeds to be similar with N.3171 obtaining 354 mph and R.6774, 355 mph. By comparison, Spitfire I K.9793 with a DH two-pitch prop and original windscreen reached 367 mph.

While costing speed, the bullet proof windscreen did prove its worth.

 

[Clean32]

More comparison data here:
View attachment 738345

Comparisons of Spitfire I's with DH and Rotol props and bullet proof windscreen found top speeds to be similar with N.3171 obtaining 354 mph and R.6774, 355 mph. By comparison, Spitfire I K.9793 with a DH two-pitch prop and original windscreen reached 367 mph.
View attachment 738346

While costing speed, the bullet proof windscreen did prove its worth.
View attachment 738348

more interesting if the different wings were noted. or do we take the assumption? would explain more of the Mk2s speed?

 

[PAT303]

This graph if nothing else shows just how much an improvement the MkIII was over the MkI/II/V not excluding everything else in the air in 1940, such a missed opportunity.

 

[Mori]

I hope we can all go home now, this appears to be pretty categorical proof that "all operational fighter and bomber stations" were not only stocked with aircaft "approved" for use with 100 grade (which we already knew), but that also, the only way it could be stored was the REMOVAL of the old 87 remaining. This was it says complete by the end of June 1940. View attachment 738005

I let things calm down a little, and take that for a genuine remark. These paragraphs are pretty interesting and I don't dispute their conclusion.

But a document lacking date, from / to, and context is of little-to-no relevance.

(Having to remind history method 101 keeps puzzling me)

 

[rochie]

I let things calm down a little, and take that for a genuine remark. These paragraphs are pretty interesting and I don't dispute their conclusion.

But a document lacking date, from / to, and context is of little-to-no relevance.

(Having to remind history method 101 keeps puzzling me)

It seems there has been plenty of documentation shown with dates included.
Yet you dont seem to want to believe what they are saying ?

 

[pbehn]

I let things calm down a little, and take that for a genuine remark. These paragraphs are pretty interesting and I don't dispute their conclusion.

But a document lacking date, from / to, and context is of little-to-no relevance.

(Having to remind history method 101 keeps puzzling me)

The document specifically states that it was giving the operational situation up to the end of June 1940, which is relevant to the Battle of Britain generally stated to be from July to October. It explains in part why Park had a Hurricane as his transport, whatever he used had to run on 100Octane fuel.

 

[rochie]

Any more snide comments and i will delete this thread

 

[DerAdlerIstGelandet]

Any more snide comments and i will delete this thread

Start with thread bans young padawa. Lets not punish the posters interested in learning without all the snide remarks and BS.

 

[Engineman]

The idea of CS propeller was that it changed its pitch automaticly. I cannot say on the early Rotols from top of my head but IIRC the VDM propellers (licenced Hamilton Standard type) used by Germans were CS but at least in those used later in Bf 109Gs had also a manual use option.
Pilot could not do anything with a fixed pitch propeller either but he had to change pitch with a two position variable pitch propeller. Take off and climb used one setting and level flight another. One could kill himself and/or wreck his plane by taking off with wrong setting and had to watch his engine speed while diving for not to ruin his engine by overspeeding (too high rpm)

Hi,
Just a couple of words about the German VDM WW2 propellers. Possibly, before WW2 VDM took out some licensing on Hamilton Standard V.P. Props or patents? However, the VDM V.P props fitted during the wartime period were quite different. Generally, the VDM props were remotely electrically actuated, with pitch change by a differential co-axial geartrain and blade root wormgear. The early Bf 109 E versions started pre-war with a simple instrument panel Coarse/Fine selector. This was a simple V.P prop and had no automatik function.
Then a Throttle lever thumbswitch control was fitted to the Bf 109 which allowed propeller control with hand on throttle. The propeller position was still physically indicated on a "clock" type scale and this indicated blade angle. Approximately, during the BoB period the Automatik version of propeller pitch control was added. The Automatik version had engine rpm control by the propeller pitch, linked directly to throttle position, unlike most Allied systems that developed with an engine speed lever, that could be set independently from throttle position. The Automatik VDM system could still be operated in the original "Hand" or manual method, just by selecting the desired method on an electrical switch.
The earliest reference I have to the VDM Automatic control is 1938, but it does seem that system was not properly introduced until 1940.

Eng

 

[Juha3]

Hello Engineman
Thanks a lot for the correction and very useful info.

Thankfully
Juha

 

[Engineman]

Hello Engineman
Thanks a lot for the correction and very useful info.

Thankfully
Juha

Thanks.
It is also worth considering the German foresight in the development of their engines and propellers. In around 1933, the RLM specified that the new fighter engines should have features that included engine mounted cannon and fuel injection. The early development engines took a little while to get F.I sorted out but, from the start, the DB 600 and JuMo 210 engines had an integral blast tube and gun mount on their prop shaft, with the supercharger moved to the side flank of the engine.
The VDM propeller was developed with the requirement to allow the propshaft blast tube from the start.
The Bf 109 had difficulties with integrating the motor-mounted gun, and development with such weapons was slow, not really making full progress until the Bf 109 F in late 1940, although the engine itself and the propellers had been ready before that.

Eng