Hurricane Mk IIC cannon:drum-magazine or belt-fed?

[Graham Boak]

To fulfill an earlier promise:
The removable weight of the eight Brownings and 2,876 rounds is 405 lbs.
The removable weight of four Hispanos and 362 rounds is 754 lbs.

So the effect of the cannon would be almost twice that of the machine gun fit.

The positioning of the weapons in the wings would indeed affect handling rather than performance, but the extra weight would affect the climb and acceleration, although not the top speed. It is 2/3 the weight of carrying a pair of 250lb bombs, where the effect on handling etc. is perhaps more easily recognised.

Inertia roll coupling can occur when large masses are offset from the aircraft centreline. The extreme case is of course something like the He162, where the offset is asymmetric. In the Spitfire/Hurricane's case the masses are symmetric; but any yaw and roll, as might well appear in combat, would introduce asymmetries. I'm not strong on stability and control (never was, I was a performance man) but I suspect you are right that the effect would show as a Dutch Roll. Not welcome when a stable firing platform is required.

[Ruy Horta]

Forgive me if it has been covered before, lot of text to read, but has anyone thought of the fact that there may not have been a reliable belt fed system at the time of the Mk.IIc development?

[John Beaman]

Perhaps, Ruy, but the MGFF seemed to be reliable and the British certainly had examples to review.

[Johnny .45]

Originally Posted by Ruy Horta

Forgive me if it has been covered before, lot of text to read, but has anyone thought of the fact that there may not have been a reliable belt fed system at the time of the Mk.IIc development?

-Ruy-
Well, I don't know if it was entirely reliable yet, but I've discovered that the Hurricane Mk IIC does indeed have belt-feed magazines...as I was beginning this thread, I happened across a photo of RAF armorers loading ammo into a Hurricane MkIIC. It plainly showed the crewman holding a belt of 20mm ammo, and the magazine covers were lying on the wing in beside the openings...it appears that the electric feed-mechanisms were actually fixed to the inside face of the detachable magazine covers. Maybe it just looks that way; here's a link to the page, if you want to see for yourself (the photo is half-way down the page, on the right-hand side.) http://www.quarry.nildram.co.uk/RAF%20guns.htm
These pages are really quite informative..."right up my alley", as they say. I am into guns and weaponry almost as much as war-planes! Maybe you've heard of "Anthony G. Williams"? He made this whole site about aircraft weaponry, etc, and I believe he's an author as well.
Anyway, this is all guesswork, but it is possible that the Mk IIC was initially drum-fed, but switched to belt feed later on in the production run. Somehow I doubt it, but it could have been the case; aircraft have been modified quite significantly, yet still retained the same designation. If a P-47D can either be "razorback" or bubble-canopied yet still be a "P-47D", then I suppose a Hurricane could be a Mk IIC even if they altered the armament a bit.

-John Beaman-
What is your meaning? As far as I know, other than a few minor experiments the MG FF was never belt-fed. Are you talking about the MG 151/20 perhaps? The MG FF had several weak-points, and one of them was the fact that it was restricted to drum magazines that only held 60 (sometimes 90) rounds and were hard to fit into the wing of a plane (same with the early HS.404).
The Bf 109 Emil had a pair of MG FF's in the wings, but the F and G both had single MG 151/20's firing through the engine block. The Japanese used a license-made version, the Type 99-1 and a version with increased power called the Type 99-2. Both were drum-fed.
In any case, having an example of a reliable German belt-feed mechanism would have possibly helped a bit, but not all that much. The problems with making a belt-feed for the Hispano were entirely different than the MG 151. The 151 was designed from day one to be belt fed; the Hispano was designed to have the rounds forced into the chamber from a drum, so there was no ammo-feed pawl to pull the rounds into the gun. That's why the British ended up using the "Chatterault"(sp?) mechanism, an electric motor to pull the ammo-belt into the gun. Basically, the gun couldn't "tell the difference" between that and a drum...the motor simulated the spring-loaded forced-feed of the drum, and so they didn't have to make (very) extensive modifications to the breech, etc to get a belt-fed gun.
In any case, I think most of the problems with the Hispano's reliability came from it's bolt and the fact it was intended to be mounted in an engine-cannon configuration, not on it's side in the wing. I'm sure they had a few wrinkles to iron out with the electric mechanisms, but nothing too serious. It was getting the gun itself to work that was the REAL issue, regardless of whether it was eating ammo from a drum or a belt.

[John Beaman]

Forgive me, I mis-interpreted the question.

[Johnny .45]

Originally Posted by John Beaman

Forgive me, I mis-interpreted the question.

That's odd...your post is missing the last sentence for some reason. The notification I received from my Yahoo mail account has a second sentence, about the MG 151. Did the forum screw up somehow? Or was it edited, maybe? It wasn't anything that anyone should take offense over.
Anyway, the MG 151 was a whole different deal...it was designed as a belt-fed weapon, while the Hispano was not. So having access to it's mechanism wouldn't have helped the Hispano at all, unless there was a major redesign of the whole action of the gun. They could have used it to help design a new gun, but I consider the Hispano a superior weapon to the MG 151 in most aspects anyway. I guess a smaller, lighter (and weaker) gun like the MG 151 would have been handy as defensive armament on bombers, etc, or as a vehicle weapon, but there just wasn't time for all that.