Pratt & Whitney R-1830 performance chart

[Matt09]

G'day,
First time on here, can you tell me if the R-1830 as fitted to the Boomerang & DC3 was supercharged or not.
Thanks, Matt09.

[Harri Pihl]

Yes, the R-1830 in the Boomerang and DC-3 featured a single stage, fixed speed supercharger.

[Jukka Juutinen]

At least the R-1830-90C as fitted in the Dakota IV had a two-speed supercharger. I assume you meant single-speed by "fixed speed". And I believe the Boomerang had 2-speed supercharged variant as well.

[Matt09]

Thanks guys, I was wondering why the Boomerang was handicapped at altitude, I guess the supercharger wasn't up to it.
I wonder if the designers just had to make do with what was available at the time, the two speed version if available would have made some difference at altitude.
Tks again,
Matt09