I’ve checked, today, with a recently-retired manager, from Martin-Baker, and the explanation is perfectly simple; nothing to do with the type of airframe, or aerodynamics, like Everest, it was there. It needed to be tandem-seating, and there was one available, so they got it up and running.
It’s only used for low-speed (max about 250) and low-level ejections; high-speed use a rocket-sled. The aircraft are owned by the MOD, and the “Seven and a half” designation is official, not a joke. The pilot was having difficulty with directional control, when trying to position, exactly, for the cameras, so Gloster were approached, and they recommended fitting the F.8 tail unit, since it had been devised due to problems with control. They’re likely to continue for some time, yet, since there are four new Derwent engines still in stock at Chalgrove.
Edgar

Standard rate for the Mk.I-IV (the IX didn’t carry the Mk.V) was 650rpm, and the capacity of the (V)C wing was 120 rpg.
Edgar

“Combat Codes,” by Vic Flintham & Andrew Thomas, also gives “US” codes as being worn by 2 Squadron, IAF, with a “not absolutely sure” caveat, but with the feeling that, as their Audaxes wore the US code, which had been allocated, pre-war, to 28 Squadron, other aircraft would have been similarly marked.
Edgar

As written by Bruce Robertson:-
15 Aug.30 Notification that R.A.F. aircraft would have the order of rudder striping changed from blue, white and red from the rudder post to red, white and blue. Contractors notified that this would be effected from 29.Sep.30. Aircraft in service were to be re-painted with two coats of bright red and bright blue, on the existing blue and red stripes respectively, and finished with one coat of clear dope by 31 Oct. 30.
Edgar

I went to the National Archive, today, and managed to find the pages, from the ORB, for those dates. I’ve had them printed onto A3 sheets, so, if you let me have an address, I’ll get them into the post, next week.
Edgar

There’s a file, in Kew’s National Archive, which might be relevant; DSIR 23/15011 is headed “Hurricane II aircraft Z3687 fitted with special wings of low drag design: flight tests.”
Edgar

RM – ‘chute straps first, please – assuming that the pilot had the sense to leave his ‘chute in the seat & not do a duck walk from the tailplane, crash his ‘chute against the canopy when entering & then slam it down onto the edge of the seat!!
Would you trust your ‘chute after this??
PS I would be airborne before this chap was seated!!

Not always, since, early in the war, the pilot could be allocated a different aircraft each time he flew, and, especially during 1940, it was common to see the same aircraft flown by four pilots in one day, or maybe two, in the case of a P.R.
One of the reasons for entering the Spitfire from the port side was because the wing surface was stronger there. There were strict instructions not to walk over the area, on the starboard wing, of the radiator, since the surface could be “dished,” which would impair the radiator’s efficiency, and require a replacement wing to be fitted. Note, too, that the early car-door Typhoons were entered from the starboard side, so port entry wasn’t written in stone.
Edgar