The pilots control over rpm would thus be via the constant speed control (which is not a pitch control) and not via throttle either.

Not true I think, on approach one sets the CSU control (or commonly called the pitch control) lever to fully fine & then adjusts the throttle for engine revs & hence airspeed. If one needs a go-around just open the throttle to max & on a Gipsy Six II one gets 2400 rpm. Closing the throttle will then give more drag.
From googling I found a reference to a May 2 nd 1935 Flight Global description of various types of ‘constant speed’ airscrews, & it would seem the props are virtually the same for both hydraulic operated VP & Constant speed airscrews but the VP only has a 3 way valve to vary its angle, so either full fine or full coarse, whereas the CSU is just an intermediary variable pressure device with the addition of a speed governor linked to the pitch lever.
I can now understand that a bit better, so one can in theory adjust the pitch angle with the lever at any revs, one just then needs the boost gauge to know how much power is applied to the prop; whether its in the optimum efficient position for that phase of flight is another matter!
Electrically operated props seem to be able to be varied throughout the pitch range & the early ones had no governor, so pilot needs to monitor revs more closely in order to not overspeed the engine.
Keith

Proctor’s with Gipsy sixes are fitted with CSU’s & constant speed props. They also have a prop lever to adjust the prop pitch at a specific throttle setting. The Boost gauges is needed to know the power demanded by the throttle, which is not needed in a fixed pitch prop aircraft as the rpm tells you that. AFAIK in geared engines ( e.g.Merlins) the rpm indicator is reading engine rpm not prop rpm. In my fathers Proctor one would take off in fine pitch at full throttle, then at a safe height he would bring back both the throttle & prop control to achieve a cruise setting of 1900 rpm & the ‘ideal’ prop pitch for that rpm, which IIRC gave about – 4 psi boost & a consumption of about 9.5 Imp gallons per hour at 135 mph indicated. Mixture control was automatic but for extreme economy one went from full rich to full weak, usually above 5000 ft, nothing in between.
When air racing at full throttle one was also in full fine pitch, the prop angle possibly hitting the coarse stops at max IAS.
Thats my recollection, probably needs to be corrected by someone more technically au fait with the system.
Keith

Beermat, Thanks for the Radiator duct drawing, but I think the carb/supercharger intake is right at the front of each engine cowling & is I believe the front half of the exhaust stub fairing. That then seems to be ducted aft on each side of the engine. Why Petter didn’t take a bleed off the radiator duct, or the wing L.E. which would give a shorter duct, I don’t know.
Keith

….., I cannot account for boost variation.

I have only found two pictures showing the intakes & a very poor one indicating the ducts alongside the camshaft blocks. The intake picture shows a very bad design of the lip as far as I can make out & its right behind the prop spinner; a good place to initiate a shock wave or an air leak at that gap which would not be very well sealed, that could blank the intake. Thats not to mention the close proximity of the blade root that will provide interference surely?
If the ducting aft of the intake was not proportioned to provide a plenum to recuperate pressure, then could not the supercharger in trying to draw in more air & would in so doing lower the intake pressure, which could affect the Mach number in the duct & producing an internal shock wave choking the supercharger? Am I going off at a tangent?
I don’t know of any other aircraft with an intake in that location so close to the prop. I think the Allison Mustangs & Merlin Mustangs & later Spits had their intakes further forward, but I believe they had plenum chambers before the compressor.
I’m being devils advocate here as I don’t have the technical knowledge, but being a devils advocate was my employment in days gone by……
Keith

Sorry to hear of Les’s passing, I know he was very happy to meet up & to help you & your team, Mike.
R.I.P Les.
Keith

”Sorry, trying to claim credit for something done by others is very bad form…
Rolls Royces were built in the USA in the 20s, but no one has ever said RRs were American”

Nobody ever said the Jaguar cars were Indian although the TATA MOTOR’s own the company..Globalisation !

Or before that, American, in the name of…..FORD!
Keith

Re TSR.2: without delving into various tomes to be absolutely certain, IIRC the resonance on the first flight was due to the early ‘not really cleared for flight’ development engines, nothing to do with the airframe, and was expected. What wasn’t expected was that the frequency would be exactly right – or wrong – so Bee Beamont couldn’t see.
The undercarriage problems, I think, were due to the 180° rotation required and took some solving but aircraft after XR219 had an extra link. As they never flew, who knows…

From memory & being in the middle of the book the sequencing problem seemed to have been sorted quite easily, but the vibration on touchdown was 90% cured by changing the angle of the fore/aft beam so that the front wheels touched down just ahead of the rears & thats what the link was doing. A rigid one was tried & there was then a telescopic one designed & fitted but not flown. Seems gyroscopic reaction of wheel spinup was the cause. Also mentioned once but not referred to again as being a possible cause, was that the steel material for the prototypes legs were not as specified because of lack of availability, so possibly more flexible?
Keith

I follow a TSR-2 fan page on Facebook, and often see posts of an ‘if only…’ nature, usually with images of TSR-2s in fictitious camouflage finishes carving up the countryside at zero feet. From what I’ve read, it seems that the TSR-2 had such major issues with undercarriage sequencing that the first trial flights were flown with the gear extended, and that subsequent flights encountered other issues with the landing gear not locking into place correctly. I’ve also read that at certain throttle settings the pilot would be blinded as the aircraft was matching the resonant frequency of the human eye. The latter might have been an unforeseen phenomenon, but the former seems avoidable, which leads me to think that the undercarriage infrastructure on the TSR-2 was poorly designed. Were there other design issues with the TSR-2? On the fan pages the notion is always that a perfectly designed aircraft was killed off by meddling, and downright treasonous, civil servants. I imagine the truth is slightly less clear cut.

I’m reading Damien Burke’s story of the TSR2 Britains Lost Bomber, a very in depth history & a lot of problems I was not aware of even though I was part of the Weybridge Design Office team on the forward fuselage. I would suggest a read of this is essential in order to gather an overall respect for the project & the issues involved. (Sorry, but Tim Mclellands version of the story is lightweight in comparison.) It must also be remembered that it was responsible for shot gun weddings of existing aerospace companies (with all that entails) & the wrong choice of engine by the Ministries, as well as being the very first weapons system project where there were no previous examples for the civil servants (with all of the inertia that goes with them) to refer. Camo colours were not fictitious, they were researched & very possible examples drawn up after calculations of A Bomb flash temperature increase possibilities on the structure. Trouble is it always looks better in white!
Keith