MiTasol
1st Lieutenant
Another of Japans problems, according to the Germans was discussed on pages 16/17 of the same file.
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Your heavier engine with shaft and fan now needs the firewall moved even further aft or a lot of additional weight in the tail. That will probably cost a lot more than 5-10 mph also
'My' fighter will loose even more speed, since I want 1st and foremost a fighter that can 1st suplant and then replace Zero in all of it's iterations (carrier-based 1st, then as land-based fighter, then as a floatplane conversion) in a timely manner. And I want it all on the fighter - 4 cannons, protection for fuel and pilot, useful fuel tankage + drop tanks, good/very good/excellent speed, RoC, dive and roll; folding wing, and preferably the butterfly flaps. Designing a fighter around Kasei can provide all of that, Sakae will not cut it, and Homare is too late.
Okay, we'll install floats on 100 of the next-gen fighters so that mission is covered.
Deciding to just defend only means relinquishing initiative to the enemy. Long range is essential in the Asia/Pacific vast expanses, since it can allow for concentration of forces. Short range fighters based at Kyushu will have hard time to help out above Honshu and vice-versa. Defence of the Ryukyus demands long-range fighters, so does the air fight ove China.
Hello Tomo Pauk,
I do not believe these objectives are all achievable with the amount of power of the Mitsubishi Kasei engine. Of course we may have different ideas on what "useful fuel tankage" means, and what constitutes proper protection for the pilot and fuel, but just keep in mind that the Raiden carried a relatively large amount of fuel for a Japanese fighter and still didn't have great range with the Kasei engine. Its speed was excellent for a J-fighter but only adequate when compared to its adversaries.
The "mission" was no longer required by the time the program was completed. THAT was the point I was trying to make.
Regardless of whether it was ideal, this is what actually happened. There were no long range successors to A6M and Ki 43.
I believe that was what the choice of swapping the Sakae engine for the Kinsei on the A6M fighter really meant and this was why the choice was made so late. Without the Sakae engine in the A6M, the Japanese Navy no longer had a long range fighter.
- Ivan.
Amout of fuel was not that large once we account for engine power that was 50+-% greater than Zero, Ki-43 or -61. 390+180 internal is in the ballpark with what Japanese fighters with 1000-1100 HP carried, while fuel in drop tank was less than Ki 43 or Ki 61 carried. 'Useful range' should be about 90% of what Zero was doing.
Kasei was making better power than any Japanse engine before Homare emerged. 1500-1800+ HP is a lot more than Ha 40 was capable for. That engine powered rangy Ki-61 that nobody considered as a pushover in air combat.
Having a fighter whose performance is adequate is a big an advantage vs. having a fighter whose performance is inadequate.
No problems. We will waste no time to convert the production line from a floatplane fighter design into a 'classic' fighter (since the production line already makes those), unlike what happended with the Kawainshi fighters' saga.
Of course they don't have a long range fighter once Zero gets a proper engine - a direct result of IJN wasting time and resources into niche aircraft instead of crucial thing: the timely replacement for the Zero.
Ki-84 was almost as rangy as Ki-43.
Not sure I'd agree that the ki61 was not competitive with later designs unless by later designs you mean verry late in the Pacific war stuff, p51, late model f4u etc.Hello Tomo Pauk,
Internal fuel capacity was nearly identical for J2M and A6M3-22 and A6M5-52 at around 570 liters. The J2M COULD carry up to a 400 liter drop tank which was larger than any carried by the A6M series. The fuel capacity of the Ki 61-I is not a great comparison because depending on the exact model, it could vary from 500 liters up to 750 liters.
The Ki 61-I may not have been a "pushover", but it also was not particularly competitive in any aspect of its performance either. At best, it was adequate against competition such as a P-40 and totally outclassed by later aircraft. It would have been great had it been available in 1941.
I still don't see how you can expect decent performance from the same engine as on J2M while adding all of the additional features needed to make it into a good carrier fighter with excellent range.
The Kawanishi line of development created possibly the best all around fighter operated by the Japanese Navy. The alternative you are describing SHOULD HAVE HAPPENED is very hard to compare when there can be no details or specifics.
The Ki 84 used the same engine and carried the same fuel load as the N1K2-J. The N1K2-J had substantially less range than the A6M fighters as has been described in interviews with surviving Japanese pilots.
- Ivan.
Not sure I'd agree that the ki61 was not competitive with later designs unless by later designs you mean verry late in the Pacific war stuff,
Huh? Different arena, different combat conditions, demands and expectations, sounds like a non sequitur comparison to me. It would seem to make more sense to gauge competitiveness in light of the time and place and opposition in question rather than some arbitrary universal scale. Or maybe I'm just out in left field. Wouldn't be the first time.As near as I can tell it had verry similar performance to a late F/ early G series 109.
I don't think anyone would argue those were not competitive with mid war designs
Hello Tomo Pauk,
Internal fuel capacity was nearly identical for J2M and A6M3-22 and A6M5-52 at around 570 liters. The J2M COULD carry up to a 400 liter drop tank which was larger than any carried by the A6M series. The fuel capacity of the Ki 61-I is not a great comparison because depending on the exact model, it could vary from 500 liters up to 750 liters.
The Ki 61-I may not have been a "pushover", but it also was not particularly competitive in any aspect of its performance either. At best, it was adequate against competition such as a P-40 and totally outclassed by later aircraft. It would have been great had it been available in 1941.
I still don't see how you can expect decent performance from the same engine as on J2M while adding all of the additional features needed to make it into a good carrier fighter with excellent range.
The Kawanishi line of development created possibly the best all around fighter operated by the Japanese Navy. The alternative you are describing SHOULD HAVE HAPPENED is very hard to compare when there can be no details or specifics.
The Ki 84 used the same engine and carried the same fuel load as the N1K2-J. The N1K2-J had substantially less range than the A6M fighters as has been described in interviews with surviving Japanese pilots.
- Ivan.
I should have made more clear I was referring to performance stats, climb, dive , top speed etc. Which is what the poster I was answering seemed to be referring to.Huh? Different arena, different combat conditions, demands and expectations, sounds like a non sequitur comparison to me. It would seem to make more sense to gauge competitiveness in light of the time and place and opposition in question rather than some arbitrary universal scale. Or maybe I'm just out in left field. Wouldn't be the first time.
Cheers,
Wes
I think that I agree in practice. However, I have been playing at designing the perfect fighter with a Kasei and it is not very hard because the Kasei length, diameter and weight are all less than those of the R-2800. Thus I simply imagine mounting a Kasei in a Grumman Bearcat, which assumes that information on the design of the Fw 190 v5 had been sent to Japan on the Raider Komet and arrived by November 1940.....snip...
I still don't see how you can expect decent performance from the same engine as on J2M while adding all of the additional features needed to make it into a good carrier fighter with excellent range. ...snip...
- Ivan.
Not sure I'd agree that the ki61 was not competitive with later designs unless by later designs you mean verry late in the Pacific war stuff, p51, late model f4u etc.
Even then although for sure it was not as good I don't think I'd say it wasn't competitive at all.
As near as I can tell it had verry similar performance to a late F/ early G series 109.
I don't think anyone would argue those were not competitive with mid war designs and even later ones to a degree.
Ki-61 carried circa 750 liters internally, unless people opted not to fill all internal tanks, or removed an internal tank. It also carried two drop tanks, so it was easily better in that regard than J2M. Once we facture in the greater power (and thus consumption) of the Kasei vs. Ha-40, no woder the range was short vs. what Ki-61 offered.
What Ki 61 needed by late 1943/early 1944 was a substantial increase of engine power, that didn't happened until 1945.
I can expect decent performance of 'my' fighter since it will have 50+% more engine power than the current carrier-borne fighter.
I think that I agree in practice. However, I have been playing at designing the perfect fighter with a Kasei and it is not very hard because the Kasei length, diameter and weight are all less than those of the R-2800. Thus I simply imagine mounting a Kasei in a Grumman Bearcat, which assumes that information on the design of the Fw 190 v5 had been sent to Japan on the Raider Komet and arrived by November 1940.
The initial Ha-32-13 Kasei for the Raiden prototype gave 1460 ps at 2450 rpm for take off and 1420 ps at 2000 metres and 2200 rpm or 1300 ps at 6000 metres at 2200 rpm. The R-2800-22W used by the Grumman Bearcat prototype was rated at 2,100 hp for take off and 1,600 hp at 16,000 ft. The Bearcat prototype attained 393 mph at sea level and 424 mph at 17,300 ft. If we take the ratio of 1600 to 1300 as 1.2308 (neglecting the effect of ps vs. hp and the different altitudes), we might expect to only lose about 9% of maximum speed using the v cubed approximation. Thus we might expect a Bearcat with a Kasei-13 equivalent engine (without the extension shaft) to have a maximum speed of at least 389 mph at around 6,000 metres.
The prototype Bearcat had 160 US gallons of internal fuel (606 litres) although that was increased to 183 gallons (693 litres) in the production aircraft. As the Raiden had around 570 litres, a Bearcat derivative should go further.
We will have to move something to maintain the CoG as the Kasei is significantly lighter than the R-2800. I doubt if a Japanese oil cooler design from 1941 will be as efficient as that of the Bearcat. Fortunately, we don't need to design a new airfoil as the Bearcat's NACA 23018 was used in the Brewster F2A.
My point was that the Bearcat designers made a brilliant job of building the smallest and lowest drag fighter possible with a R-2800 engine and seem to have produced a lower drag design than Mitsubishi, whose J2M1 could only manage 357 mph at 6,000 m with the Kasei-13 (which did not use water injection). To get speeds around 380 mph, Mitsubishi needed to fit the Kasei-23 which gave 1900 ps at 2600 rpm for take off and ratings at 2500 rpm of 1720 ps at 2100 metres or 1580 ps at 5500 metres with water injection. The Kasei-26 of the J2M5 was optimised for higher altitude and gave 1400ps at 6800 metres, which allows an easy comparison with the R-2800-30W of the F8F-2.
The Bearcat is heavier because it has a heavier engine, armour and an arrestor hook as well as generally thicker skinning and the strength to land repeatedly on a carrier. The empty weights are 7,650 lbs for the F8F-2 and perhaps 5534 lbs for the J2M5. Naturally, the extra weight is necessary for a carrier fighter.
Lastly, Mitsubishi did do a better job in one respect as the Raiden had good spin recovery whilst the Bearcat was rather more dangerous near the stall.
I am profoundly agnostic on the performance of the Raiden. Fortunately, we have a survivor so it should be possible to measure everything exactly and use software developed to predict the performance of modern aircraft. The two obvious problems are cost and that there may not be good programs to predict cooling drag.Hello Cherry Blossom,
I believe the biggest difference of opinion here is what you believe the maximum speed of the J2M series really was.
I am inclined to believe the TAIC data sheet which gives about 407 MPH under Military Power and 417 MPH under "War Emergency Power" for the J2M3. It seems like you are more inclined to believe the more typically quoted 370 MPH figure... snip ...
The weakness in the wings was linked to the wing folding. A Japanese Bearcat would not need folding wings if it were a land based fighter or might even be accepted on an IJN carrier without folding as it would still be smaller than their dive bombers. Either way, it would save weight and have stronger wings.The Bearcat also had some load factor limitations because of the design for break-away outer wing panels. Eventually this was addressed but it took a very long time.
- Ivan.
Ever hear of the term disc loading; the horsepower applied to a prop divided by the area of the thrust- producing portion of the prop? The heavier the disc loading, the more power is "wasted" in tip vortices, noise, and heat. Ever hear a small, high powered floatplane (Maule M4, Cessna 185, 206, 207) trying to climb out of a small lake in a narrow mountain valley? BBLLLAAAAATTAAOOWWW! That's wasted power from a high disc loading. The obvious solution is a larger propeller, but the floats get in the way. More blades help raise the total thrust output somewhat, but at the cost of weight, expense, and less efficiency of each individual blade.Does that reduce the Bearcat's drag or make its propeller more efficient?