Yes indeed Sensei!
A small what if: IJA goes with Ki-44 as their main fighter?
- Thread starter tomo pauk
- Start date
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GrauGeist
Generalfeldmarschall zur Luftschiff Abteilung
The Japanese did capture several US types that had a variety R-1830 engines before the F4F.
- Thread starter
- #23
Those engines were all with 1-stage superchargers, the better of them making 1000-1050 HP at 13000-15000 ft. The 2-stage supercharged R-1830 as installed on F4F-3 and -4 was doing 1100 HP at ~18500 ft.
Shortround6
Major General
The Germans were using intercoolers on some Jumo 211s.
The 2 stage superchargers on the P&W R-1830s in the Wildcats weren't all that good.
The Two stage Wildcats were good for around 1050hp at around 20,000ft. Accounts vary.
The Single stage single speed Sakae was good for about 950hp at 4200 meters so the F4F looks pretty good.
However the single speed two stage Sakae was good for about 980hp at 6000 meters (19,685ft) and the F4F doesn't look so good.
If they had stuck the Kinsei 51 into a A6M they could have had 1100hp at 6200 meters in 1942.
The Kinsei 62 gets you 1180hp at 5800 meters. A 20% increase in power at just about 20,000ft without needing two stage superchargers.
Yes the Japanese needed to upgrade/change engines much sooner than they did. If they cannot compete with high octane fuel and with high pressure ratio superchargers then use larger engines that are stressed less/ use superchargers with a lower pressure ratio.
And that is something that often is not taken into account. Not everybody's superchargers were even close to the same efficiency.
Granted you have to start from somewhere but if you stick a couple of impellers that are operating at less than 70% efficiency things get strange real quick.
A lot of rich mixture is actually using fuel as an internal coolant in engines that don't use water injection.
The water-alcohol actually gets rid of more heat per gallon than a gallon of fuel does but there are limits.
RR did a couple of studies or test engines using single stage superchargers using water injection and intercoolers (not in combination on the same engines.)
They were able to get 1150hp from a Merlin at 23,000ft using 9lbs of boost using either water injection or with an intercooler. They were using a higher than normal supercharger gear. Using the supercharger from a Merlin 47 they were able to get 1100hp at 26,000ft using an intercooler (no idea how it was big was) using 9lbs of boost.
The DB605 using the bigger the supercharger from the DB 603 gained around 2000 meters of altitude. It paid for it on the low end. It didn't use an intercooler.
Somebody once said that if your 2nd stage supercharger isn't very good all it does multiply the problems the 1st stage supercharger has.
In the early 30s of lot of companies were using using single stage superchargers weren't very good, but if you are are only using 2-3lbs of boost it is hard to tell.
A lot of 1944-47 superchargers offered much different capabilities than 1938-41 superchargers did.
The 2 stage superchargers on the P&W R-1830s in the Wildcats weren't all that good.
The Two stage Wildcats were good for around 1050hp at around 20,000ft. Accounts vary.
The Single stage single speed Sakae was good for about 950hp at 4200 meters so the F4F looks pretty good.
However the single speed two stage Sakae was good for about 980hp at 6000 meters (19,685ft) and the F4F doesn't look so good.
If they had stuck the Kinsei 51 into a A6M they could have had 1100hp at 6200 meters in 1942.
The Kinsei 62 gets you 1180hp at 5800 meters. A 20% increase in power at just about 20,000ft without needing two stage superchargers.
Yes the Japanese needed to upgrade/change engines much sooner than they did. If they cannot compete with high octane fuel and with high pressure ratio superchargers then use larger engines that are stressed less/ use superchargers with a lower pressure ratio.
And that is something that often is not taken into account. Not everybody's superchargers were even close to the same efficiency.
Granted you have to start from somewhere but if you stick a couple of impellers that are operating at less than 70% efficiency things get strange real quick.
The water injection is a crutch.
A lot of rich mixture is actually using fuel as an internal coolant in engines that don't use water injection.
The water-alcohol actually gets rid of more heat per gallon than a gallon of fuel does but there are limits.
RR did a couple of studies or test engines using single stage superchargers using water injection and intercoolers (not in combination on the same engines.)
They were able to get 1150hp from a Merlin at 23,000ft using 9lbs of boost using either water injection or with an intercooler. They were using a higher than normal supercharger gear. Using the supercharger from a Merlin 47 they were able to get 1100hp at 26,000ft using an intercooler (no idea how it was big was) using 9lbs of boost.
The DB605 using the bigger the supercharger from the DB 603 gained around 2000 meters of altitude. It paid for it on the low end. It didn't use an intercooler.
Somebody once said that if your 2nd stage supercharger isn't very good all it does multiply the problems the 1st stage supercharger has.
In the early 30s of lot of companies were using using single stage superchargers weren't very good, but if you are are only using 2-3lbs of boost it is hard to tell.
A lot of 1944-47 superchargers offered much different capabilities than 1938-41 superchargers did.
- Thread starter
- #25
It is about the Japanese get the idea of actual use of 2-stage supercharger on a mass-produced miliraty engine, rather than about how good the 2-stage R-1830 was (it was mediocre, for a host of reasons).
You probably mean 'two-speed single stage Sakae' instead of 'the single speed two stage Sakae'.
Japanese are already using the bigger engines than the Merlin, V-1710 or R-1830. Problem was that fighters with the bigger engines were in a strict minority vs. the fighters using the small Sakae.
We know that a Kinsei 62 will not cut it after 1943 when Allies up their game.
Mid-a and late-war Japanese 1-stage superchargers were among the best?
A Ha 109 engine that uses the small impeller from the early Sakae and the big impeller from the Ha 109 ( so the 2-stage supercharger is made) would've been interesting.
The Ha43-42 ended up as probably the only Japanese 2-stage engine captured, yes, it was too late to matter. It used the 'sidewinder' set-up. (Ha43-11 was the basic, 1-stage version)
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Shortround6
Major General
Yes, I am making more mistakes than usual due to the health condition.
Well, they used Kinsei 62s in the Ki 100 fighters in 1945. Not ideal but if introduce in 1943/early 1944 a huge improvement over the almost 2500 KI 43s built during 1944/45.
- Thread starter
- #27
My no-so-well-hidden agenda is to have the Ki-43 production ended by the late 1943.
Kinsei 62 in the nose of the Ki-44 would've produced a faster fighter than it was the Ki-100; not by some alchemy, just by the virtue of the Ki-44 having a much smaller wing.
BTW: people are usually jumping to point out the Homare's ... temperamental nature. Perhaps making it with a much reduced compression ratio - from 7:1 down to perhaps 6:1 - would've reduced the stresses of operating at high boost and RPM, while being less picky on octane rating of the fuel used?
