PDA

View Full Version : Hurricane I - 12lbs boost



SeaDog2007
10-09-2007, 08:40 PM
Hi, all. Is there some way to mod the engine controls to allow overboost?

I recently discovered, that as of March 1940, all Hurricane and Spitfires, using the Merlin II/III engine were cleared to use 12lbs of boost (rather than 6.25lb) in emergencies, for up 1/2 hour. This produced an increase in speed of 31mph at 5000ft and 29mph at 10,000ft, in the Hurricane I, and caused a spectacular increase in climb rate as well. I would guesstimate, that a Rotol prop Hurricane I could climb to 20,000 ft in about 7 minutes, using overboost. This has rather important ramifications for the Hurricane and really increases in low level performance. For more info on this please see this site:
http://www.wwiiaircraftperformance.org/hurricane/hurricane-I.html
specifically:
http://www.wwiiaircraftperformance.org/ap1590b.jpg
and
http://www.wwiiaircraftperformance.org/hurricane/hurricane-l1717-cal.jpg
and
http://www.wwiiaircraftperformance.org/hurricane/l2026.html
where you should note that climb and speed trials are done with 6.25lb boost, so a 12lb boost Hurricane would be quite a hot ship.

SeaDog2007
10-09-2007, 08:40 PM
Hi, all. Is there some way to mod the engine controls to allow overboost?

I recently discovered, that as of March 1940, all Hurricane and Spitfires, using the Merlin II/III engine were cleared to use 12lbs of boost (rather than 6.25lb) in emergencies, for up 1/2 hour. This produced an increase in speed of 31mph at 5000ft and 29mph at 10,000ft, in the Hurricane I, and caused a spectacular increase in climb rate as well. I would guesstimate, that a Rotol prop Hurricane I could climb to 20,000 ft in about 7 minutes, using overboost. This has rather important ramifications for the Hurricane and really increases in low level performance. For more info on this please see this site:
http://www.wwiiaircraftperformance.org/hurricane/hurricane-I.html
specifically:
http://www.wwiiaircraftperformance.org/ap1590b.jpg
and
http://www.wwiiaircraftperformance.org/hurricane/hurricane-l1717-cal.jpg
and
http://www.wwiiaircraftperformance.org/hurricane/l2026.html
where you should note that climb and speed trials are done with 6.25lb boost, so a 12lb boost Hurricane would be quite a hot ship.