Pratt Whitney R-2000 Twin Wasp (upgrade for R-1830 powered planes?)

[gjs238]

An enlarged version of the R-1830

Would a much earlier availability of this engine have been a feasible upgrade for R-1830 powered planes?
I'm thinking that major modifications and production disruptions would not be necessary.

How would R-1830 powered planes have performed with the R-2000?

Pro: Perhaps planes such as the F4F could have seen worthwhile performance increases earlier than their replacements like the F6F were fielded.
Pro: Perhaps planes such as the B-24, which served with R-1830's for the length of the war, could have seen worthwhile performance increases.
Con: Perhaps expediting development of the R-2000 would have come at the expense of the R-2800 or R-4360.

Secifications (R-2000-3) Data from*FAA Type Data Certificate (TCDS)[1] General characteristics Type:*Twin-row radial engine, 14 cylinder Bore:*5.75 in (146 mm) Stroke:*5.5 in (139.7 mm) Displacement:*2,004 cu in (32.8 L) Length:*61.02 in (1550 mm) Diameter:*49.49 in (1257 mm) Dry weight:*1570 lb (714 kg)

Specifications (R-1830-S1C-G) Data from* Tsygulev (1939).[3] General characteristics Type:*Twin-row radial engine, 14 cylinder Bore:*5.5 in (139.7 mm) Stroke:*5.5 in (139.7 mm) Displacement:*1,829.4 in³ (30 l) Length:*59.06 in (1,500 mm) Diameter:*48.03 in (1,220 mm) Dry weight:*1,250 lb (567 kg)

 

[oldcrowcv63]

Weight increases by factor of 1.26, as does frontal area by factor of 1.06 whereas engine power to weight ratio drops from 0.96 hp/lb to 0.86 hp/lb. Seems like it might not provide much benefit for the effort. Dunno if there are other considerations.

 

[davebender]

For another 500lbs you can have a 1,600hp R2600 engine. Which is probably why USN dive and torpedo bombers skipped over R2000 engine for the R2600 engine.

 

[tomo pauk]

The R-2000 was skipped because it was too late to matter - 1st run, going by Wikipedia (usual disclaimer applies) was in 1942.

 

[gjs238]

The R-2000 was skipped because it was too late to matter - 1st run, going by Wikipedia (usual disclaimer applies) was in 1942.

Would a much earlier availability of this engine have been a feasible upgrade for R-1830 powered planes?

.

 

[gjs238]

For another 500lbs you can have a 1,600hp R2600 engine. Which is probably why USN dive and torpedo bombers skipped over R2000 engine for the R2600 engine.

Yeah, I agree, but the R-2600 is a fatter engine.
The R-2000 perhaps offers the promise of a slick upgrade.

 

[davebender]

Fat R2600 engines work just fine in fat and rather slow dive and torpedo bombers.

Fighter aircraft might have been a different matter. However USN opted for 2,000hp over weight and aerodynamic considerations when writing specifications for F6F and F4U.

 

[Shortround6]

I think we have been over this at least once

R-2000 engine is much later in timing than the R-2800.

They built 9 engines in 1941, 8 of them in December. While not a large production item in 1942 that could have been changed if needed. Problem is that the R-2000 didn't really offer much for combat planes in 1942 over the R-1830s.

The early R-2000s were rated on 100 octane fuel (not 100/130) and were good for 1350hp for take-off, 1350hp military at 2000ft and 1100hp at 13,200ft in high gear. A R-1830 rated on 100 octane was good for 1200hp take-off, 1200hp at 4900ft and 1050hp at 13,100ft. Apparently they didn't change the supercharger much from the R-1830 to the R-2000. Unless the R-2000 powered plane stays really low it doesn't have much advantage over the R-1830 powered plane.

 

[Shortround6]

For another 500lbs you can have a 1,600hp R2600 engine. Which is probably why USN dive and torpedo bombers skipped over R2000 engine for the R2600 engine.

Timing.

R-2600 was available over 2 years before the R-2000.

They didn't skip over it. It didn't exist when design work was started on the USN dive and torpedo bombers.

 

[Shortround6]

Fat R2600 engines work just fine in fat and rather slow dive and torpedo bombers.

Fighter aircraft might have been a different matter. However USN opted for 2,000hp over weight and aerodynamic considerations when writing specifications for F6F and F4U.

Actually they considered the aerodynamics rather well.
A R-1830 has about 12.6 sq ft of frontal area and 1200hp down low and 1000 hp (with a two stage supercharger) at 19,000ft. POWER per sq ft of frontal area is 95.24 down low and 79.37 at altitude.
A R-2800 has about 14.8 sq ft of frontal area and 2000hp down low and 1650 hp (with a two stage supercharger) at 22,000ft. POWER per sq ft of frontal area is 135.14 down low and 111.49 at altitude.

That one seems like a no brainer. Corsair's wing was only about 21% bigger than a Wildcats wing so the power per unit of skin friction seems pretty good.

Throw in the fact that a 1200hp engine couldn't cope with load of guns and ammo the the Navy wanted and the choice doesn't need anymore explanation.

 

[davebender]

Meanwhile typical V12 engines had frontal area of 6 to 7.5 sq feet and were plenty powerful enough for contemporary fighter aircraft such as Spitfire, Me-109 and Macchi C.205. USN could have specified Allison or Packard V12 for next generation fighter aircraft. Instead they opted for maximum engine power.

 

[Shortround6]

Switching the argument here?

The F6F and F4U were Navy planes and weren't going use liquid cooled V-12s if there was another option.

Now lets throw in the fact that the US Navy wanted more range/endurance than the Spitfire, Me-109 and Macchi C.205 could offer. A 1200-1300hp V-12 couldn't handle the required fuel load. Granted the R-2800 sucked up a fair amount of fuel but throttle back to slow cruising speeds and the Corsair was burning about 25% more fuel than a Spitfire or P-40. Considering that the fuselage tank held about twice as much fuel as a Spitfire or 109 this gives it a LOT more range /time to find the carrier when returning from a mission.

 

[Aozora]

Switching the argument here?

The F6F and F4U were Navy planes and weren't going use liquid cooled V-12s if there was another option.

Now lets throw in the fact that the US Navy wanted more range/endurance than the Spitfire, Me-109 and Macchi C.205 could offer. A 1200-1300hp V-12 couldn't handle the required fuel load. Granted the R-2800 sucked up a fair amount of fuel but throttle back to slow cruising speeds and the Corsair was burning about 25% more fuel than a Spitfire or P-40. Considering that the fuselage tank held about twice as much fuel as a Spitfire or 109 this gives it a LOT more range /time to find the carrier when returning from a mission.

Lets also throw in the fact that the R-2800 was highly reliable, and could cope with lots of battle damage that the average liquid-cooled engine couldn't; there were a lot of USN pilots who were very grateful for the choice made by the USN when facing a flight of (say) 250 miles across deep, empty oceanic waters.

 

[Shortround6]

The R-2800 hadn't shown shown it's resistance to battle damage at the time it was chosen (1939-41) but one less system to wrong (the liquid cooling system) was a consideration.