Author Topic: Guns synchronization (Read 363 times)

MANDOBLE · « **on:** February 10, 2002, 06:40:38 PM »

Just done some tests with Ta152 151/20 guns and Ki61.

Ki61 (2x20mm) needs 9 seconds to spend all its 20mm ammo (240 rounds).
Ta152 (2x20mm) needs 12 seconds to fire 240 20mm rounds. Both planes used synchronized guns.

Why that difference between planes with synchronized weapons?

Staga · « **Reply #1 on:** February 10, 2002, 07:20:06 PM »

More rpm's in Ki's prop ?

MANDOBLE · « **Reply #2 on:** February 10, 2002, 07:23:11 PM »

hehe Staga

Both planes tested with engine stoped on runaway and airborne, max MAN and RPM, same results.

Pongo · « **Reply #3 on:** February 10, 2002, 09:50:35 PM »

if they have modeled a different rof for the 152 and the Ki it will be because the prop blade is much broader on the 152 so the sycronization has to be more severe. I doubt they model the real act of sycronizing the guns. They probably just work out a factor to sycronize by and allways apply that

Hooligan · « **Reply #4 on:** February 12, 2002, 02:10:14 AM »

Ho-5 has a better rate of fire than the Mg151. Also, the Ki's guns are pretty far outboard. I believe they are not synchronized.

Concerning synchronization effects: In another thread Pyro said the following.

Quote

There's a lot of factors that go into how synchronization affects rate of fire. Just changing your engine RPM affects rof, but trying to create a real model of interruptor gear goes well beyond the point of diminishing returns. In AH, all synchronized guns are treated the same with a fire rate set to 90% of the weapon's unsynchronized rof.

Hooligan

MANDOBLE · « **Reply #5 on:** February 12, 2002, 02:20:27 AM »

Hooligan, Ki guns are over the engine of the plane (similar conf as 109 Mgs), the wing weapons are the Mgs (unsynchronized).
No matter if unsynchronized Ho-5 has better ROF than Mg151 when they are both sychronized in Ki and Ta.

Pongo · « **Reply #6 on:** February 12, 2002, 02:44:02 AM »

Sorry. I thought the Ki actually had cowl mounted 151s recieved from Germany.

Hooligan · « **Reply #7 on:** February 12, 2002, 12:32:00 PM »

The Ho-5 has a better rate of fire than the Mg151 (whether both are unsynchronized or both synchronized).

I believe HTC uses 700 and 630 for the rates of fire for Mg151s. I have measured these several times.

For the HO-5: 120 rounds in 9 seconds translates to 800 rounds/sec. For an unsynchronized gun this would be about 890 rounds/sec. In the book "Rapid Fire" Tony Williams gives a rate of fire of 700-850 for the Ho-5.

If HTC is using 850 for the unsynchronized Ho-5 ROF then 765 would be the synchronized ROF. It should take 9.4 seconds to fire all the cannon ammo in the Ki-61.

Perhaps the Ho-5 ROF is too high in AH. Maybe there is a bug and the gun is firing at the unsynchronized rate. Also, it is quite possible that the your timing test was off by .4 seconds. I also timed the guns and came up with 9 seconds but I believe my test was accurate to within a half a second at best. So even though I timed it at 9 seconds I have no doubt that it might have been 8.8 seconds or 9.4 seconds (for example).

Hopefully Pyro will enlighten us.

Hooligan

Raubvogel · « **Reply #8 on:** February 12, 2002, 12:38:54 PM »

They dont account for Prop RPM, Prop width, etc. They just take the guns unsynchronized ROF and reduce by I believe 10%. So the higher ROF weapons are still going to be faster.

FDutchmn · « **Reply #9 on:** February 12, 2002, 04:37:52 PM »

Quote

Originally posted by Pongo
Sorry. I thought the Ki actually had cowl mounted 151s recieved from Germany.

Only some of them when the Ho-5 was still under development, as I recall. The Ki-61-Ia and Ki-61-Ib had the german 20mm. The one modelled on AH, the Ki-61-I-KAIc had the Ho-5s.

Mitsu · « **Reply #10 on:** February 13, 2002, 01:24:41 AM »

No, FD.
that's not right.

Ki-61-I-Ko (Ki-61-I-a) has 2 12.7mm and 2 7.7mm.
Ki-61-I-Otsu (Ki-61-I-b) has 4 12.7mm.
Ki-61-I-Hei (Ki-61-I-c) has 2 MG151/20 on wing and 12.7mm on nose.
Ki-61-I-Tei (Ki-61-I-d) has 2 Ho-5 on nose and 2 12.7mm on wing (Ki-61-I-KAI-c in Aces High, but actually it should be called as Ki-61-I-d).

------------
Mitsu
Stab./JG1 "Oesau"
"Let me fly Tony, it's an Axis plane!"

Mitsu · « **Reply #11 on:** February 13, 2002, 01:41:39 AM »

I don't know HTC simulates guns synchronization in Ki-61 or not.

The RPM of nose mounted Ho-5 20mm cannon of Ki-61-I-KAIc is 850 in Aces High.
It's true spec. My several sources say real Ho-5's RPM is 750 - 850rpm.

...or maybe, the RPM of synchronized Ho-5 is 750rpm.

------------
Mitsu
Stab./JG1 "Oesau"
"Let me fly Tony, it's an Axis plane!"

Mitsu · « **Reply #12 on:** February 13, 2002, 01:49:29 AM »

Ho-5 (aka Type 2) 20mm Cannon Specifications

Caliber: 20mm
Length: 1,435mm
Weight: 39kg
Barrel Length: 900mm
Muzzle velocity: 735m - 750m/s
Rate of Fire: 750 - 850rpm
Effective Range: Unknown
Ammunition: 20 x 94
Available ammunition types: Type 2 HE, Type 2 TR-HE, Type 2 TR-AP, Ma-202 HE
Round Weight: 84.5g

------------
Mitsu
Stab./JG1 "Oesau"
"Let me fly Tony, it's an Axis plane!"

FDutchmn · « **Reply #13 on:** February 13, 2002, 06:17:33 AM »

Quote

Originally posted by Mitsu
No, FD.
that's not right.

Ki-61-I-Ko (Ki-61-I-a) has 2 12.7mm and 2 7.7mm.
Ki-61-I-Otsu (Ki-61-I-b) has 4 12.7mm.
Ki-61-I-Hei (Ki-61-I-c) has 2 MG151/20 on wing and 12.7mm on nose.
Ki-61-I-Tei (Ki-61-I-d) has 2 Ho-5 on nose and 2 12.7mm on wing (Ki-61-I-KAI-c in Aces High, but actually it should be called as Ki-61-I-d).

Eeek gadz! Really? Did I read it wrong?....

hmmmm..... ok, I am mistaken with the impression that all Ki-61-Ia and Ki-61-Ib had the MG151/20s... according to Mr. J. Baugher only some of these models were fitted with the German MG151/20s (source: Aircraft of the World )

Quote

Specification of Kawasaki Ki-61-1b Army Type 3 Fighter Model 1b:

One Army Type 2 twelve-cylinder liquid cooled engine (Kawasaki Ha-40) rated at 1175 hp for takeoff and 1080 hp at 11,480 feet. Performance: Maximum speed 368 mph at 15,945 feet. Cruising speed 249 mph at 13,125 feet. An altitude of 16,400 feet could be reached in 5 minutes 31 seconds. Service ceiling 37,730 feet. Normal range 373 miles, maximum range 684 miles.

Dimensions: Wingspan 39 feet 4 7/16 inches, length 28 feet 8 1/2 inches, height 12 feet 1 11/16 inches, wing area 215.3 square feet.

Weights: 4872 pounds empty, 6504 pounds loaded, 7165 pounds maximum. Armament: Two fuselage-mounted 12.7 mm Type 1 (Ho-103) machine guns and two wing-mounted 7.7 mm Type 89 machine guns (Ki-61-Ia). Two fuselage-mounted 12.7 mm Type 1 (Ho-103) machine guns and two wing-mounted 12.7 mm Type 1 (Ho-103) machine guns (Ki-61-Ib). Some Ki-61-Ia and -Ib aircraft had the wing guns replaced by 20-mm Mauser MG-151/20 cannon.

Specification of Kawasaki Ki-61-I-KAIc Army Type 3 Fighter Model 1c:

One Army Type 2 twelve-cylinder liquid cooled engine (Kawasaki Ha-40) rated at 1180 hp for takeoff and 1100 hp at 11,480 feet. Performance: Maximum speed 366 mph at 13,980 feet. An altitude of 16,400 feet could be reached in 7 minutes. Service ceiling 32,810 feet. Maximum range 1120 miles.

Dimensions: Wingspan 39 feet 4 7/16 inches, length 29 feet 4 inches, height 12 feet 1 11/16 inches, wing area 215.3 square feet. Weights: 5798 pounds empty, 7650 pounds loaded.

Armament: Two fuselage-mounted 20 mm Ho-5 cannon and two wing-mounted 12.7 mm Type 1 (Ho-103) machine guns and two wing-mounted 12.7 mm Type 1 (Ho-103) machine guns.

...Mitsu, I am sure you are right, could you take this up with Mr. Baugher?

Mitsu · « **Reply #14 on:** February 13, 2002, 09:31:29 AM »

Ah...sorry FD, I missed some.

I forgot some Ki-61-I-a and Ki-61-I-b mounted MG151/20 at front line (New Guinea etc).

But, not all.

-Mitsu

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