gloster F9/37

Hood said:
The Peregrine I was single speed MS. I wonder if Bristol elected to modify the Taurus for high S gear in order to compete better with the Peregrine. The Peregrine had +9lb boost, the standard Taurus II only +2.75lb.
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Peregrine was FS, 1-speed. Making 885 HP at 15k ft, on +6.75 psi (87 oct fuel). Indeed +9 psi was for 100 oct fuel (1000 HP? at ~11-12 kft?)
 
Hi Tomo,

tomo pauk said:
Problem with all this math is that doing greater RPM and turning the big impeller as fast as it is needed rises the indicated power (IHP = BHP + losses), stressing the engine a great deal more than running it at lower rpm and with less demands by supercharger.
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Well, actually if you run the engine at the same boost pressure and rpm, the engine will run about at the same indicated power level as with the smaller/slower supercharger, except for a somewhat decreased charge mass due to the higher temperatures after the supercharger that are inevitable when you're compressing air.

However, driving the larger/faster supercharger subtracts more power from the indicated power level, leaving less useful power at the propeller shaft. If you look at the power chart for a typical two-speed supercharger equipped engine, you can estimate the slope of the propeller shaft power loss from higher supercharging by extrapolating the line between the two peaks. For a single-speed supercharged engine, physics are the same, just not as easy visualized :)

In the case of the Hercules VI, switching gears from low gear to high gear increased full throttle height (at +6 lbs/sqin boost) from about 5000 ft to 13000 ft, while power at the propeller shaft decreased by 10 %. The greater the increase in full throttle height, the bigger the power reduction.

(See https://enginehistory.org/Turbochargers/Superchargers/BristolSuperchargers.shtml )

So maybe the same Taurus that with its standard supercharger yields 1050 HP @ 5000 ft will only be good for rougly 920 HP @ 15000 ft with a larger/faster supercharger, if we can use the Hercules as a yardstick.

Compared to a Peregrine at +6.75 lbs/sqin boost, which yields 885 HP, that's not much of a difference, especially considering that the Peregrine is a smaller engine with a nicely streamlined cowling and an exhaust system better suited to exploit exhaust thrust.

Accordingly, I don't really think that a Taurus-engined version would necessarily have had the reported 30 mph speed advantage over the Peregrine-engined version on an "everything else being equal" basis.

Regards,

Henning (HoHun)
 
HoHun said:
Accordingly, I don't really think that a Taurus-engined version would necessarily have had the reported 30 mph speed advantage over the Peregrine-engined version on an "everything else being equal" basis.
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Agreed 100%.
 
How was the cockpit of the Gloster F.9/37 entered? Was it through the canopy? If it was, was this a sliding canopy or side hinged?
 
Dead link
Sorry, Tony, your link in #25 seems to have died...
 
I can answer my own question now. Aeroplane Monthly, February, 2006, has the same photo of the cockpit that appears in one of the posts on this thread. But this photo has a caption, indicating that the canopy hinges on the starboard side.
 

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