P&W 1830 question

[pinsog]

Is a 2 speed P&W 1830, say a -33 model, a direct belt in replacement for a -17 model? Wondering if anything would need to be changed on a P36/Hawk 75 to accommodate a 2 speed engine?

 

[Shortround6]

Not sure what you get???

See performance data for the P-36B.

http://www.wwiiaircraftperformance.org/P-36/P-36B_38-20_sept-25-1939.jpg

The -23 engine used an 8:1 supercharger gear vs the 7.15 supercharger gear of the normal P-36 engines. The two speed engines used a 7.15 low gear and an 8.47 high gear.

It appears (?) that the difference between the 8:1 supercharger gear and the 8.47:1 supercharger gear was about 50hp at 14,300-14,500ft (no RAM) at 2700rpm.

The two speed engine does allow you an extra 100hp for take off

 

[pinsog]

Not sure what you get???

See performance data for the P-36B.

http://www.wwiiaircraftperformance.org/P-36/P-36B_38-20_sept-25-1939.jpg

The -23 engine used an 8:1 supercharger gear vs the 7.15 supercharger gear of the normal P-36 engines. The two speed engines used a 7.15 low gear and an 8.47 high gear.

It appears (?) that the difference between the 8:1 supercharger gear and the 8.47:1 supercharger gear was about 50hp at 14,300-14,500ft (no RAM) at 2700rpm.

The two speed engine does allow you an extra 100hp for take off

It also allows you to use that 1200 hp up to 5,000 feet. Should give you about 323 mph or so at 17,000 feet. Be a nice improvement for a P36 over an 1830-17 engine

 

[pinsog]

You know at the bottom of the wwiiperformance P36 Page there is a sales brochure from Curtis giving all the specs for the P36? If you compare the specs of the Wright 1820 powered Hawk75 to the British tests, the numbers match up perfect. The P&W 1830 numbers show 323 mph at 15,000. I couldn't figure out how that was until recently. The P&W S3C3-G in the sales brochure is identicle to the 1830-23. The Curtis sales brochure is only 5 mph faster than the US army tests with the 1830-23 and the US tests lists 317 mph at 17,000 feet while the Curtis brochure lists 323 mph at 15,300 feet. Made me wonder what the climb rate would be down low if it had another 100 hp. Top speed would be an extra 5 mph with 50 more hp.

 

[pinsog]

 

[pinsog]