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

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gjs238

Tech Sergeant
1,889
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Mar 26, 2009
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)

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

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