issue with Ho-103 machine guns? Ki-84, A6M5b?

[Krusty]

Whatever the case may be, I was throwing out an example. Sorry if it's not realistic. It's just the general description somebody once gave to describe that not all synchronizations are equal. Especially for Browning HMGs. They did not synch well.

[icepac]

Doesn't quite work that way...

It's not just based on RPM. It's the cycles of when the prop passes in front of the gun and the natural cycles of the gun itself. If they are complimentary, things don't slow down much. If they just happen to be odd cycles you get much less windows of opportunity.

True...there will be a certain sweet spot in the rpm range where it will fire faster than either higher or slower rpms.

[BaDkaRmA158Th]

So what it comes down to is the same guns mounted in the wings have a uninhibited rate of fire, where as ones firing through a prop will have a semi limited rof.

 

[Krusty]

It's more than that... The guns outside the props (for example) fire as fast as they can. The guns inside the prop are actually cut out and restarted. Depending if the rate of fire was cyclic or whatever, this start stop is also going to slow things down too. Some interrupter mechanisms were electric and some mechanical, and in the case of the electric they simply wouldn't send the "fire" signal but once or twice during a "prop opening".

You'll find german guns synch'ed well. They liked doing that. Japanese guns seem to always have had that problem.

Although our Ki-61's 20mm guns are synched and fire very fast. I imagine they should be a bit slower.

[Bino]

...
That made me wonder... The Ho-103 was common, right? You find it on our Ki-61 as well, but this is outside of the sync area, and fires unhindered from the wings. Doing an AH test gives roughly 882 rpm for those wing guns. Not bad.
...

Actually, the relatively late version of the Ki-61 Hien we have in right now AH has two 20mm Ho-103 in the nose synchronized to fire between the propeller blades.  There was an earlier version of the plane in RL that had an imported German-made Mauser MG-151/20 in each wing, mounted outside of the prop arc.  But we don't have that one in-game.  Yet.  <crosses fingers hopefully>

[Krusty]

Bino, the Ho-103 is a 12.7mm MG, not a 20mm cannon. The Ki-61 has the MG in the wings.

I think it might be interesting to have the earlier variant with the MG151/20 in the wings (just as a curiousity) but I think the ammo count was the same or close.

[Bino]

Oops!  My bad, sorry!

[EagleDNY]

I think this is less a case of the ROF of the guns and more a case of which synchonization technology is used in a particular ride.  The WW-I rides are all mechanical / cam synchronized, but since the guns were all in the 450rpm range, and you had props turning in the 1200 rpm range (on a rotary, more on an in-line engine) - this was sufficient to give you full ROF on the guns.

By WW2, the guns are firing faster, the engines are turning much more rpms, so they have a variety of different syncho methods they use.  This sounds to me like the Ki-61 was using an older mechanical syncro system instead of one of the newer synch gear or electrical systems. 

If you want to check out a cool synchro system, do a search on the british sonic system.