Japanese doing things different in for before and during ww2?

[Shortround6]

A few weights
type.......................................empty..............................loaded..................................max
Ki-100...................................5567lb.............................7705.lb.................................8365lb
A6M5....................................4130lb..............................6050lb.................................6510lb
A6M8....................................4740lb..............................6945lb*..............................--------

The A6M5 may be for an early version. I believe the loaded weight for the A6M8 is for "standard Load" but could be wrong.
The Early A6M5 had two 7.7mm guns and two 20mm type 99-II guns with 100rpg. The A6M5a got the belt feed guns with 125rpg and later versions swapped one 7.7mm for on 13.2mm gun. The A6M8 had the two 20mm 99-II MK 4 with 125rpg and two 13.2mm guns in the wings.

Please note that the 12.7mm army guns were 4-6kg lighter than the navy guns and used lighter ammo. The 20mm guns were closer to the same weight but the army gun fired faster. It also used a much lighter shell.
By the time you get to the A6M5c the net weight had gone up over 600lbs from the early A6M5's.

Since the Ki 100 used a bit smaller wing it's ability to operate off a carrier is rather suspect.

 

[SaparotRob]

Were there American carrier aircraft with similar wing loading to the Ki-100?

 

[tomo pauk]

Since the Ki 100 used a bit smaller wing it's ability to operate off a carrier is rather suspect.

Ki 100 was featherweight even compared with F8F, that was supposed to operate from small carriers. The 'combat weight' (full fuel and ammo load, clean) of the F8F-1 was ~9670 lbs, on the wing of 244 sq ft (or about 10% greater wing area of the Ki-100).

 

[Thumpalumpacus]

I'm no gearhead, but this is an interesting discussion, fo' sho.

 

[hobbes154]

Were there American carrier aircraft with similar wing loading to the Ki-100?

Wiki is your friend (at least until proven otherwise). Yes Ki-100 has lower wing loading than Hellcat and Bearcat (higher than Wildcat tho).

 

[hobbes154]

OK, the A6M8 is looking like a good option. Still not 100% convinced on the 190... the Japanese engines would still have their weight advantages in Japanese airframes, and the 190 is over a ton heavier empty than the Ki-44, which was introduced in 1942.

 

[WARSPITER]

Either way, putting a Ki-100 up against the F8F isn't going to end well for the Japanese fighter.

 

[Shortround6]

Ki 100 was featherweight even compared with F8F, that was supposed to operate from small carriers. The 'combat weight' (full fuel and ammo load, clean) of the F8F-1 was ~9670 lbs, on the wing of 244 sq ft

True but there are a number of aspects to wing loading in regards to carrier aircraft. It is a sort of short hand.

For carriers (lake land planes) it is a quick indicator for minimum flying speed. It does vary depending on actual airfoil and wing shape and what high lift devices are being used (and at what point in the flight envelope and how big each device is).
It doesn't take into account power to weight so our F9F-1 has 4.60 lb/hp and aver a 12ft prop to haul it off the carrier deck.
Ki-100 has got 5.13lbs /hp and an under 10ft prop. that is at clean weight.
Some flap is useful, a lit of flap may not work well?

On the other end you have two things to consider. The Flying speed/approach speed as it affects the aircraft as it flies and the resulting impact speed on the arrestor system and deck and the effects on the aircraft. Maintaining control is rather dependent on the aircraft and we all know that some aircraft were easier to control than others right above stall and that the actual stall speed sometimes had little to do with it.

Energy that has to absorbed by the arresting system and aircraft landing gear (we will leave the strength of the deck out of this) goes up with square of the speed of the aircraft. Increasing the speed at the "hook point" from 70mph to 75mph increases the impact force by about 14.8%. A heavier plane with a lower landing speed can use the system.
The system maybe well be able to be adjusted for the higher impact loads, up to a limit. However the aircraft sometimes require more beefing up and that is for an text book landing.
A landing that is a little "off" needs stronger landing gear. Many carrier planes had longer stroke landing gear than land planes to absorb the impacts.

Hurricane was good carrier plane because of the big wing and light weight, it actually landed slower the F4F. It had a few problems of it's own but it should not be used as an example of " if the Hurricane could do it why can't xxxxxxx?"
Also note that the F8F used slotted flaps,

Ki 61 & 100 used split flaps.
If you are designing a new plane for a joint specification you can use whatever flap you want.
However the more complicated you make the flap the more it costs and the heavier it is.

Engine in the Ki-100 was good for 1250hp at 19,000ft so it is a balancing act.

 

[tomo pauk]

True but there are a number of aspects to wing loading in regards to carrier aircraft. It is a sort of short hand.

For carriers (lake land planes) it is a quick indicator for minimum flying speed. It does vary depending on actual airfoil and wing shape and what high lift devices are being used (and at what point in the flight envelope and how big each device is).
It doesn't take into account power to weight so our F9F-1 has 4.60 lb/hp and aver a 12ft prop to haul it off the carrier deck.
Ki-100 has got 5.13lbs /hp and an under 10ft prop. that is at clean weight.
Some flap is useful, a lit of flap may not work well?

I'd be very surprised if the power/weight ratio took the engine power into the account.
Flaps were figured out 15 years before Ki-100 took flight, let's not pretend that Japanese (of all people) can't do it, and do it well.

Energy that has to absorbed by the arresting system and aircraft landing gear (we will leave the strength of the deck out of this) goes up with square of the speed of the aircraft. Increasing the speed at the "hook point" from 70mph to 75mph increases the impact force by about 14.8%. A heavier plane with a lower landing speed can use the system.
The system maybe well be able to be adjusted for the higher impact loads, up to a limit. However the aircraft sometimes require more beefing up and that is for an text book landing.
A landing that is a little "off" needs stronger landing gear. Many carrier planes had longer stroke landing gear than land planes to absorb the impacts.

Japanese were flying aircraft much heavier than the Ki-100 from the carriers, even of we allow for the weight increase due to the navalization. Includes the aircraft with high wing loading and not very favorable power loading, like the C6N and D4Y. Americans were still more 'aggressive' there, even on escort carriers. Aircraft that weighted twice as much, cancelling the possible speed disadvantage the Ki-100 equivalent might've had while landing.

Or, in other words, and combined with the above - let's not make a mountain from an ant hill.

Hurricane was good carrier plane because of the big wing and light weight, it actually landed slower the F4F. It had a few problems of it's own but it should not be used as an example of " if the Hurricane could do it why can't xxxxxxx?"

You have me scratching my head while trying to remember when I've suggested that Hurricane is a good role model for the Japanese to follow.

Ki 61 & 100 used split flaps.
If you are designing a new plane for a joint specification you can use whatever flap you want.
However the more complicated you make the flap the more it costs and the heavier it is.

You've suggested several times that split flaps work fine as air brakes, when we were talking about the Spitfire and Hurricane low-speed abilities. Seafires and 'hooked' Spitfires were taking off from carriers with a bit of flap deployed, 12 deg IIRC.

Japanese were installing excellent flaps on their fighters and bombers already by early ww2, so again let's not make a mountain from an ant hill. It will cost them far less to continue in that regard, than to make floatplane fighters, 2-engined fighters and dedicated recon aircraft (things that also messed with economies of scale do devastatingly). Good flaps were worth it, doubly so on naval aircraft.

Engine in the Ki-100 was good for 1250hp at 19,000ft so it is a balancing act.

Eye-watering when compared with 940 HP at 19000 ft as offered by the Sakae.
Granted, both Ki-100 and A6M8 were late by at least two years. By 1944, the nose of the fighters needs to house Homare, Ha 104, or at least Kasei or Ha 109 with water injection.

 

[Shortround6]

I'd be very surprised if the power/weight ratio took the engine power into the account.

What else is power to to weight going to take into account?
Unless you are referring the to size of the props. The FM-2 didn't change the diameter of it's prop but in changed the cord of the blades to get more low speed thrust from the small in crease in power.

Flaps were figured out 15 years before Ki-100 took flight, let's not pretend that Japanese (of all people) can't do it, and do it well.

In the early 30s you had pretty much the the split flap and the plain flap. Just about everything else showed during those 15 years. But the more complicated flaps took more time to fine tune. First commercial use of the Fowler flap was in 1937 and the Zap and few others were ways to get around patents, to some extent.

Japanese were flying aircraft much heavier than the Ki-100 from the carriers, even of we allow for the weight increase due to the navalization. Includes the aircraft with high wing loading and not very favorable power loading, like the C6N and D4Y.

Well, the B6N used a 400ft sq wing so it's wing loading wasn't actually that high. The D4Y had some problems working off some of the Japanese carriers. So did the C6N.

You've suggested several times that split flaps work fine as air brakes

Split flaps in early 1930s aircraft actually worked as air brakes, not lift producing devices.
They increased drag and decreased lift at the same time so the planes came in at a steeper approach angle. They made it easier to get into small airfields and shortened the ground run a bit. Hurricanes could use a number of flap settings or infinite?
Spitfires were either all the up or all the way down. They did stick wooden wedges in them for the ferry flights to Malta. Plane took off with flaps up with the wedges in place, With enough speed the pilot dropped the flaps, the wedges fell in sea and the Pilot retracted the flaps for the rest of the flight and when he landed at Malta the flaps descended to full down flap position. Some of the Seafires may have gotten hydraulic cylinders with intermediate positions? Very Early Spitfires were pretty basic. First 70 or so had manually retracting landing gear?
On most biplanes when you cut the throttle there was enough drag to slow the plane and let the pilot plant the plane on the ground. Depends on the pilot. The monoplanes were not as for giving to pilots that came in high or hot, the planes kept going and going after the engine was dropped to idle.
and these "air brakes" were low speed only. They were not to be used for slowing the plane down in combat. Either hydraulic system didn't have the power to extend the flap into the high speed airframe or you could bend/damage the flap. A number of aircraft in various actually used the airstream to push the flaps closed after take-off.

Now on some planes they did use split flaps as both landing flaps and as part of the dive bomber dive Brakes. But that requires a bit more beef in the structure and actuators.
And even then, some planes had to deploy the dive flaps before the dive, not during.

 

[tomo pauk]

What else is power to to weight going to take into account?
Unless you are referring the to size of the props. The FM-2 didn't change the diameter of it's prop but in changed the cord of the blades to get more low speed thrust from the small in crease in power.

I was commenting on this:

Since the Ki 100 used a bit smaller wing it's ability to operate off a carrier is rather suspect.

(my bold)
Wing size and weight combined give wing loading, and have no bearing on power/weight ratio.

In the early 30s you had pretty much the the split flap and the plain flap. Just about everything else showed during those 15 years. But the more complicated flaps took more time to fine tune. First commercial use of the Fowler flap was in 1937 and the Zap and few others were ways to get around patents, to some extent.

Japanese have had aircraft with Fowler flaps in use before Pearl Harbor, and used them on a host of aircraft quickly after that. The C6N used the slotted Fowler flap (similar like the A-26).
Granted, even the simpler flaps worked on carrier A/C.

Well, the B6N used a 400ft sq wing so it's wing loading wasn't actually that high. The D4Y had some problems working off some of the Japanese carriers. So did the C6N.

I've never mentioned the B6N having high wing loading.
The loaded, navalized Ki-100 equivalent will be far lighter than the loaded C6N or D4Y, to help with CV compatibility.

Some of the Seafires may have gotten hydraulic cylinders with intermediate positions? Very Early Spitfires were pretty basic. First 70 or so had manually retracting landing gear?

Hopefully, asking from Japanese engineers to include a variable control for flaps would not be asking too much.

and these "air brakes" were low speed only. They were not to be used for slowing the plane down in combat. Either hydraulic system didn't have the power to extend the flap into the high speed airframe or you could bend/damage the flap. A number of aircraft in various actually used the airstream to push the flaps closed after take-off.

Now on some planes they did use split flaps as both landing flaps and as part of the dive bomber dive Brakes. But that requires a bit more beef in the structure and actuators.
And even then, some planes had to deploy the dive flaps before the dive, not during.

Again, you have me scratching my head while looking on where I've mentioned that IJN fighters are supposed to deploy the flaps in dive, while we're discussing actual carrier capability. Or where I've said that these are supposed to deploy them in combat in order to slow the aircraft down.

 

[Shortround6]

Wing size and weight combined give wing loading, and have no bearing on power/weight ratio.

OK, power to weigh does have a bearing on getting the aircraft off the flight deck. How fast (distance) can the plane get up to flying speed?

Going back to the F8F-1A/B the Navy specs say the B with the 20mm guns was 442lbs heavier.
Rate of climb was 250-300fpm less at sea level and take-off distance with a 25kt wind was 35ft longer.
The difference is a combination of increase wing loading increased power loading.

Again, you have me scratching my head while looking on where I've mentioned that IJN fighters are supposed to deploy the flaps in dive, while we're discussing actual carrier capability. Or where I've said that these are supposed to deploy them in combat in order to slow the aircraft down.

Just trying to clarify the difference in "air brakes".
Not all "air brakes" perform the same function.
Early Flaps were sometimes called drag flaps.

The loaded, navalized Ki-100 equivalent will be far lighter than the loaded C6N or D4Y, to help with CV compatibility.

Maybe not.
The D4Y3 (Kinsei engine) was 8,276lbs loaded and 10,267lb max. lower number has 32.6lb wing loading. Higher was 40.4lb/sq/ft
Ki.100 was 35.7 lb/sq/ft at max clean and 38.8lb/sq/ft at max load.
Late production D4Y3s got three JATO rockets to help with getting off small carriers with max load.

 

[tomo pauk]

OK, power to weigh does have a bearing on getting the aircraft off the flight deck. How fast (distance) can the plane get up to flying speed?

We can take a look on the F4F-4. With 1200 HP, it was carrier-suitable with 8760 lbs (case with 2 drop tanks and full ammo). For the Ki-100, figures are 1500 HP for take off and 8365lb max T.O. weight.
Granted, navailzation will add 400-500 lbs, depending on what exactly was changed (Seafire III seems to gain ~400 lbs vs. the Spitfire Vb; includes the folding wings)?

Maybe not.
The D4Y3 (Kinsei engine) was 8,276lbs loaded and 10,267lb max. lower number has 32.6lb wing loading. Higher was 40.4lb/sq/ft
Ki.100 was 35.7 lb/sq/ft at max clean and 38.8lb/sq/ft at max load.
Late production D4Y3s got three JATO rockets to help with getting off small carriers with max load.

Our splendid naval Ki 100 would probably not be flown from the small carriers with 500-800 kg bombs and drop tanks.

 

[hobbes154]

Ki-100 has got 5.13lbs /hp and an under 10ft prop.

That seems a problem for the A6M8 and maybe other Japanese fighters in that class as well. Maybe they should add a 4th blade (easier than make the landing struts longer)? Or just wider blades?

Seems like a possible reason for the disappointing gain in speed as the Zero gained power from the A6M2 onwards.

 

[tomo pauk]

That seems a problem for the A6M8 and maybe other Japanese fighters in that class as well. Maybe they should add a 4th blade (easier than make the landing struts longer)? Or just wider blades?

Seems like a possible reason for the disappointing gain in speed as the Zero gained power from the A6M2 onwards.

The gain in speed had a lot to do with thrust increase as the war dragged on, while accounting for the speed loss due to increase of drag (and a bit because of gain in weight). Thrust was increased via engine power increase at high altitudes (15000-20000 ft in this case; at the end of the day, increase of altitude power was meager, from A6M2 to the A6M7), better prop (not sure how much that was the case) and introduction of individual exhaust stacks (speed gain was pretty good, even if the investment was tiny). For the Zeros that saw war service, speed gain equated to about 30 km/h (circa 20 mph), with a dip with the Model 52c that have gotten the increased drag due to the increased firepower vs. the the initial Model 52 (three MHGs vs. two LMGs) and due to the protection for pilot and fuel tanks; the Model 62 was in the ballpark with the 52c (speed loss vs. the fastest Zero was about 20 km/h).
A6M8 was an attempt to revert to the performance figures of the light and fast Zeroes, while still sporting the protection and increased firepower - minus one HMG - via installation of a 'proper' engine (+300 HP vs Sakae 21 up high, + 400 HP down low). This is probably an equivalent of installing the Merlin 45 on Spitfire I/II in order to cater for greater drag and weight due to installation of protection and greater firepower, but not an equivalent of Spitfire getting the Merlin 61 in order to produce a really outstanding fighter.

Problem with the A6M8 was that was way too late, even later then the Ki-100, both aircraft being roughly on par with Spitfire II or V from 1940-41.

 

[Shortround6]

That seems a problem for the A6M8 and maybe other Japanese fighters in that class as well. Maybe they should add a 4th blade (easier than make the landing struts longer)? Or just wider blades?

Seems like a possible reason for the disappointing gain in speed as the Zero gained power from the A6M2 onwards.

I have likened propeller design to witchcraft several times
For any given speed and altitude there is only one ideal propeller design for a given engine power.
A high speed aircraft (fighter) wants a smaller prop than a slow speed aircraft (transport) but a heavy aircraft wants a larger prop for take-off than a lighter aircraft.
A plane that flies at 20,000ft wants a larger prop than a plane that flies at 5,000ft at the same speed due to the thinner air.
Constant speed props help a lot but they can't cover everything. Merlins and DB engines came with different reduction gears to suit different propellers. So did most American engines. and other countries.

As Tomo has said there were a number of changes that increase the drag of the later Zeros and the increase in power did not make up for them.
Unfortunately a lot of the writing of the time and for a number of years after war just used "increased weight" as a sort of short hand for the increased drag that accompanied the increased weight. The extra drag of more gun barrels (or longer gun barrels) and more cartridge ejections slots was simply ignored or counted as "increased weight". Difference in antenna were ignored and other minor fittings.
Putting a larger than needed propeller on an airplane slows it down, much like putting larger than needed tires on a car will slow it down.

 

[Shortround6]

Our splendid naval Ki 100 would probably not be flown from the small carriers with 500-800 kg bombs and drop tanks.

The Ki-100 can't carry both at the same time, Not sure it was eve supposed to carry full internal fuel with under wing bombs as the Plane would be over the max gross weight, (which may be wrong?)

Improving the A6M much sooner may have been the way to go, That and getting the Army and Navy to both agree to use the Ho-103 machine gun.
Even if they had to use different production lines, like a land version (short range) and the carrier version (long range) with the Kinsei engine in the landplane and keeping the Sakae for the long range? or fitting under wing fuel tanks as was done later?

They could have had a Kinsei 53/54 powered version with the type 99 cannon in the wings and a single Ho-103 outboard entering production in 1943, assuming production capacity. The engines and guns were in service.
Stick the Kinsei 62 in when it becomes available. Fit whatever version of the type 99 until you can get Ho-5 20mm guns.
Install some armor BP glass and some sort of protection for the fuel tanks (even cooled exhaust gas to cut down on fires )

 

[Guchi]

A big what'if for Japan would be finding a face-saving means to withdraw to the pre-1937 borders with China. That would end the US sanctions and give Japan time to breath. In that time Japan can either build up its military, industrial capacity and oil stocks in preparation for attacking DEI, FIC, Malaya and perhaps Pearl Harbour in 1941. Or, Japan can wait to see how the ETO war is going, which by summer 1942 will appear to be going badly for the Germans, and hold off going to war at all....

Or join your traditional British allies! The Kidō Butai arrives in Britain end 1942.

Please correct me if I'm wrong, but didn't the British ditch the Anglo-Japanese treaty by simply not renewing it?
In the '20's I believe and under pressure from the US?

 

[EwenS]

Please correct me if I'm wrong, but didn't the British ditch the Anglo-Japanese treaty by simply not renewing it?
In the '20's I believe and under pressure from the US?

It was a bit more complicated than simply letting it lapse. It was all tied into the Imperial Conference of 1921, then the Washington Naval Conference of 1921/22 and the subsequent Treaty, together with the Four Power Treaty of Dec 1921. There was an awful lot of world politics in play around the time. The Wiki article is fairly well referenced but you need to scan down the page a bit.

Anglo-Japanese Alliance - Wikipedia

en.m.wikipedia.org

Four-Power Treaty - Wikipedia

en.m.wikipedia.org

And see Article XIX of the Washington Treaty limiting defensive works in the Pacific region by USA, Japan And the British Empire.

CONFERENCE ON THE LIMITATION OF ARMAMENT, 1922.

 

[tomo pauk]

Improving the A6M much sooner may have been the way to go, That and getting the Army and Navy to both agree to use the Ho-103 machine gun.
Even if they had to use different production lines, like a land version (short range) and the carrier version (long range) with the Kinsei engine in the landplane and keeping the Sakae for the long range? or fitting under wing fuel tanks as was done later?

Designing the A6M around the Kinsei from the get go?
A bigger drop tank - 400-450 vs. 300 L - can lessen the 'range anxiety' by a good deal, since, after all, Kinsei was not that much more powerful until the 60 series.
I'd try to get a better ammo capacity for the Type 99-1 ASAP, already a 90-100 rd box/drum is a boon.

They could have had a Kinsei 53/54 powered version with the type 99 cannon in the wings and a single Ho-103 outboard entering production in 1943, assuming production capacity. The engines and guns were in service.

The 50 series Kinseis (Model 51) were powering the last version of the G3M, the Model 23 a.k.a G3M3, all Nakajima production. 1st deliveries were made in April of 1941 (!). 98 were delivered in 1941, just under 300 in 1942, and last 23 in January and February of 1943 (total 412 per Japanese Wikipedia; yearly numbers per USSBS report for Nakajima company).

IOW - Japanese can have, in service in early 1942, a Zero+ with 1100 HP at 2000 ft, vs. the Zero with 940 HP at ~13500 (Mod 21; an usual occurrence back then) or with 970 HP at ~19500 ft (Model 32; to enter service in Spring of 1942).
For 1943 - the 60 series Kinsei, with another 10-15% HP more 'dry' and much more via water-alcohol injection, at least by looking the arrival of the 'better' Ki-46 in service.

Production capacity problems can be alleviated by earlier phasing out of the Zuisei family of engines, andm specifically for the Navy needs, having Aichi make exclusively the radial engines.

Stick the Kinsei 62 in when it becomes available. Fit whatever version of the type 99 until you can get Ho-5 20mm guns.
Install some armor BP glass and some sort of protection for the fuel tanks (even cooled exhaust gas to cut down on fires )

Agreed 100% on the need to make Zeros more durable against the enemy fire.
Type 99 was firing a much heavier shell than the Ho-5 (130g vs. 83g - even lighter than Shvak; the Type 99-2 was also firing at much higher MV than the 'legacy' 99-1) - the TASTAAFL rule applies as ever.