Hi guys, thanks for tuning in to another video on ForgottenWeapons.com.
I'm Ian McCollum, and today we are taking a look
at a "balloon buster". This is an 11mm Colt Vickers gun.
And these were manufactured for aerial use
... at the very end of World War One.
Now of course the British had been using the Vickers gun since well before the war.
The United States didn't adopt it, didn't look at it very seriously.
They did start doing some trials on them just before World War One.
Ultimately it would be adopted kind of as a rush,
"Wow, we really need some machine guns because apparently there's a big war going on now."
They would adopt it as the Model of 1915 in the standard .303 calibre ground configuration.
And Colt got a licence from the Vickers Company to manufacture them here in the US.
However it would take a number of years actually for Colt to manage to
actually get Vickers gun production up and running ... finally.
They ... had a number of contracts, like the initial contract was for 125 Colt Vickers guns,
and it took them more than two years to actually get those delivered to the US.
It was 1917 before those shipped.
The first contract that they really actually were able to produce in quantity
was a contract for the Russian government.
But of course the Russian Revolution put an end to that.
And ... when the Russian Revolution happened Colt ... ended up with about 1,200 Vickers guns
that had been made for the Russians, but they weren't going to get paid for now,
and they certainly weren't going to ship them.
And so they were left with them in the US. And what do we do with those?
Well, about that time they actually got a contract from the French.
The French wanted some Vickers guns in 11mm.
The French had taken the 11mm Gras cartridge and they redesigned it to be an incendiary round,
because one of ... the main aerial targets for aircraft during World War One,
aside from other enemy aircraft, were observation balloons.
We think of that kind of as quaint and like, "Oh, an observation balloon, nyah."
Well, observation balloons were very important in World War One for artillery spotting.
Artillery was massive, ... perhaps the most important weapon on the battlefield.
And being able to spot where the shells are hitting and adjust fire,
and spot where enemy troops are, that was an incredibly important element of the war.
And so what they would do is they would send observers up in balloons
with basically a telephone with a wire running back down to the ground
to keep an eye on what was going on.
And it could be decisive in a battle to prevent the enemy from having observation,
or from shooting down their observation balloons.
These are hydrogen balloons, they're highly flammable.
But little .303 calibre FMJ bullets don't necessarily do a whole lot.
Like, you can poke a lot of small holes in one of those balloons without impairing it too badly.
However, if you take an 11mm cartridge and you fill it up with some phosphorous incendiary compound,
blow that into the balloon and light the hydrogen, that gets the balloon out of the air very quickly.
So the French developed that, and then they need some machine guns for it.
The Vickers is pretty well suited to be adapted to that use.
One of the things that the Vickers had over the French machine guns,
over the Hotchkiss, is that it fires from a closed bolt.
Which means that it can be much more easily synchronised to run in an aircraft
firing through the propeller without shooting yourself down.
So, all that is to say, the French wanted some Vickers guns in 11mm,
and they were able to get them from Colt.
Colt had [these] 1,200 guns left over from the Russian contract.
They rebuilt at least 800 of them, and shipped them out to France in early summer of 1918.
The ... remainder of the guns they sent to the US Flying Corps ... rebuilt also to 11mm.
The US government in June of 1918 placed a further order for another
1,700 11mm guns, plus another 4,300 .303 guns.
And Colt started working on those and started making deliveries during 1918.
So we're talking basically the last six months of the war
is when these guns were actually in theatre in Europe being deployed.
I don't know the exact numbers and distribution of which guns went where,
but one of the US aircraft that did absolutely use 11mm Vickers guns was the SPAD XIII.
This was one of the favourite aircraft of the American flyers.
There's a great picture of Eddie Rickenbacker, if I can find it I'll put it in the video here.
On his plane you can see he's got two Vickers guns mounted on the aircraft,
one of them is a .303 gun, one of them is an 11mm gun.
So, we'll talk about the pros and cons of the 11mm in a minute,
but first let me show you what they did to make a Vickers into an aircraft gun.
When aviators started mounting machine guns in aircraft in World War One
there are two considerations that you really have to account for.
One is weight, and the other is accessibility of controls.
There were a variety of ways that these guns were mounted.
Early on in the war you would see flexible observer guns,
that's typically not the role that a Vickers gun would have played.
A Vickers like this would have been [in] a fixed mount on the cowl of the aircraft.
The idea being you can have a one-seater aircraft,
and instead of having to fly and aim a gun at the same time, the pilot simply aims the aircraft
and the guns fire right forward through the propeller over the nose of the airplane.
This ... is the most accurate, effective way to run a single-seater aircraft.
So in order to do that, first off, let's talk about weight.
Actually a Vickers gun is not really any heavier than a Lewis gun,
which is what preceded the Vickers for aircraft use.
However the water jacket is kind of an issue, the water jacket is there to cool the gun.
You need something to cool the gun because the Vickers gun has a very thin barrel
and it will overheat very quickly.
However, at the altitude and the speed that these aircraft were flying,
wind flow over the barrel would do a perfectly acceptable job of cooling, so they didn't need the water.
That ... helps get rid of some of the weight.
And what they did is cut open the jacket to enhance airflow through it.
If we start by looking at the front of the jacket
you'll see they've cut out basically as much material here as they can
without sacrificing the rigidity of the jacket in general.
You might ask, "Why not just remove the whole thing?"
And the answer is the Vickers gun requires the barrel to reciprocate,
and there has to be a bearing surface here to support the front end of the barrel.
So they have to keep the jacket in place to support the barrel.
So in order to get air flow through the front and out the back, they have cut open the front.
This is where the steam tube was, they got rid of that, obviously they don't need it.
And then they've cut a series of louvres in the front here,
and they've angled them in such a way that they're going to pull air down into the barrel jacket.
Now we'll point out this as well. ... It's not really a flash hider,
this is just a protector so that the blast from the front of the gun
doesn't damage the cowl of the aircraft directly under the muzzle.
Moving to the back of the jacket you can see that they've again cut the louvres,
but they've angled them the opposite direction.
So back here they're pulling air up out of the jacket to help it circulate through from front to back.
They've also gone ahead and cut out the whole section here
where the fill plug originally was, and that'll help bring air out as well.
And even added a couple of small holes down in the bottom.
Basically, as much material as they can take out, they have taken out.
That is pretty much the extent of the weight reduction measures that were taken on the Vickers.
The Vickers was already lightened from the Maxim design really as much as could be feasibly done.
And there wasn't a lot left to get, so just the barrel jacket.
Now the next thing to consider is access to the controls.
There are a number of different configurations of aircraft Vickers guns,
and a lot of the differences are based on how you run the charging handle.
So depending on how the guns were mounted,
you might or might not have access to a charging handle like this.
Now on this particular gun either the ... extra charging handle levers have been removed,
or they weren't necessary in the first place.
This just has a standard charging handle on it.
When you see bigger ones it usually means like the gun was mounted
inside the cowling of the aircraft instead of sitting right up on top of it,
and they had to have some sort of lever extension coming up that the pilot could actually get to.
We do have this cool modification to the fusee cover though.
Normally there is a little adjustment tab out at the front of the fusee spring,
and this allows you to adjust the spring tension of the gun.
So if the gun's not running reliably you could adjust the tension up or down on the spring,
which is one of the cool parts of the Vickers and Maxim design.
However, if you've got this thing mounted on the nose of your airplane,
you might be able to get to the charging handle in the back,
but I guarantee you you're not going to be able to adjust that fusee spring tension.
So what Colt did is they actually made a different [spring cover]
that allowed you to ... change the spring tension from the back.
At the front, instead of the regular lever, you have a gear wheel.
That is then connected to this second gear sprocket,
which connects to a long operating rod running back.
And that ends with a square profile. So there's a little wrench
that you could put on this that would allow you to turn it and adjust the spring tension.
One of the other obvious changes to the aircraft guns are brackets like this,
and these are meant to attach synchronisation gear.
So the whole idea of synchronisation is that ... if you're shooting through the propeller's arc of travel,
you don't want to shoot your own propeller off - for obvious reasons.
There are two different ways that you can work around that, well there are three really.
The simplest way is put big heavy metal armoured deflector plates on the back of your propeller,
and don't care, bullets that hit the propeller will just bounce off.
People did that for a while, but it's not really an optimal solution.
So there are two other ways to do it, and they involve hydraulic or mechanical links to the engine
that will either prevent the gun from firing if the propeller is in front of the muzzle,
or fire the gun mechanically only when the propeller is not in front of the muzzle.
The first of those would be an interrupter, and the second would be a synchroniser.
Synchronisers were definitely the better, the more efficient or elegant way to do this.
There are a number of ways that it could be done. You could have a rod
(most of them were mechanical connections),
you could have a rod that would pull the trigger when the propeller was passing the right point in its travel.
You could have a rod that would push the trigger. ... Pulling was better than pushing
because you could use a much smaller connecting bar.
However, even better than pulling or pushing would be rotating, and that's what this was set up for.
These guns use the French designed Birkigt [system]
(it's b-i-r-k-i-g-t, I'm not entirely sure how to pronounce that),
Birkigt system in which there was a connecting rod that came back here connected to the engine.
I'm sorry, it would come here and come through this clamp, be held there.
And then it would rotate clockwise and counterclockwise as the engine turned.
So it would oscillate back and forth, and when it did
it pushed on this (which has a rather heavy spring)
pushed on that lever. This lever goes through these little cuts in the top cover,
and activates the trigger right there.
That little square stud sticking up out of the lock is the actual sear that fires a Vickers gun.
So normally the trigger mechanism comes in through the top cover.
For this synchroniser connection instead, it's right there, you can see it working just like that.
This synchroniser system was developed by the same guy who designed the engine for the SPAD.
So it made sense: he designed the engine, he can figure out how to link it to a gun.
It goes into the SPAD, the SPAD is what the Americans are using, at least largely,
and hence the American guns will largely have this style of synchroniser mechanism.
Now there are a couple of other mechanical changes that were made to the guns.
First off, we have a strengthened top cover spring here
to make sure that this doesn't come up unintentionally.
This is just a big ol' flat spring that you have to lift up against in order to open the gun.
And it's (there we go), it's really quite stiff, but that's pretty simplistic.
If you look back here, of course you don't have the regular spade grips
because this wouldn't be fired by the regular thumb triggers.
You do have this which is a buffer tube.
Now there's normally a flat spring on there that has broken off,
that's going to prevent this from unscrewing.
But what we have was a guide rod,
and you can see it right there.
This ... particular gun is missing two little pieces:
there should be a big spring and a cover plate.
And basically what this is is a buffer, so that when the action bars and the lock
reciprocate backward upon firing, they will hit that buffer.
That will decelerate them and prevent the gun from taking a beating.
Because remember this is in 11mm Gras, this is a very large, heavy recoiling cartridge.
More so than the .303 that the Vickers was designed for.
This also has the secondary effect of then accelerating the parts to go back forward,
which is going to help boost the rate of fire back to something more acceptable for aircraft use.
We also have a modification to the feed block and to the feed block locking mechanism.
On the ground guns there's a little lever that allows you to open this.
On the aircraft guns they put a bolt in with a cotter pin to hold it in place,
because there was no good reason to be opening this in flight.
A belt of 11mm Gras is a lot heavier than a belt of .303,
and the feed block system was not quite up to fully reliably pulling 11mm Gras [through] the gun.
So what they did is add a booster spring here.
That just gives this feed block a little extra push to snap back over
and help feed the belt in.
So this spring comes out ... and it's a pretty simple deal, that's it.
Didn't require any mechanical adjustment or change to the feed block.
It just snaps in there.
So that is a feature that you will find on the 11mm balloon buster guns.
Of course the feed block itself is machined differently on the inside
to accommodate the 11mm Gras cartridge.
But it is otherwise interchangeable,
the ... receiver dimensions are the same for the 11mm guns as they were for .303.
The markings on these guns are actually on the front of the water jacket.
This is Vickers Machine Gun Model of 1915, because that is what the ground gun
was originally adopted as in US service.
Colt's Patent Firearms Company, Hartford, Connecticut.
A serial number, and these are typically relatively high serial numbers
because the first 800 or so went to the French.
So when you find them in the US they're typically American service guns.
Some of them will have an "A" prefix number as well, I believe those are the French ones.
And then in this case a 1917 inspection date.
Although that's earlier than they actually got into combat service in France.
This is turning into a pretty lengthy video,
but there's a little bit more that I want to show you, namely the ammunition.
So the Vickers was designed around cloth belts.
And that worked fine, it was nice and cheap and easy, and worked fine on the ground.
However in an aircraft role, if you had your typical 250 round belt
(or if you're on an aircraft perhaps you would want even more, ... a winder spool with 500 rounds, say),
... halfway through that belt you don't want to have 250 rounds of cloth belt
(which would be many yards of belt), flapping out along the tail of the aircraft
potentially going to get caught in something and cause problems.
So instead they developed disintegrating metal link belts.
These are Prideaux links, there are a couple of different designs of them that were used.
But the idea is simply to have a flexible belt, for one thing, that you could wind up on a spool.
And that every time you fired a round it would simply discard
an individual link off the side of the aircraft, and prevent them from causing trouble.
This is very standard: like these took over after World War One in place of cloth belts universally.
But they were originally developed for aircraft use. So this is a belt of .303.
We are very fortunate to have a 4 round belt of 11mm Vickers, or 11mm Gras incendiary.
These are extremely rare today, and you can see the link design is basically the same.
But what you have is a link will hold the front and back of one cartridge, and centre of the next.
So it's the cartridge itself that holds all the links together.
When you pull one of these out (I can show you here),
when you pull one of these out, the links are going to separate just like that.
I mentioned earlier on that Rickenbacker had both a .303 and an 11mm Vickers gun on his aircraft.
And there are pros and cons to the 11mm.
You might look at this and say, "It's big bore and incendiary, what wouldn't I like?
Why not just equip all ... the aircraft with all 11mm guns?"
Well, there were some downsides to it.
You can't carry nearly as much ammunition because the ammo is bulkier, heavier.
And I don't know that the 11mm incendiary ammo was really
that much more effective than .303 on a fighter aircraft.
This is World War One, we're talking wood and cloth framed airplanes.
The incendiary isn't going to have a chance to do a lot.
What makes it really effective on balloons is the fact that they're filled with flammable hydrogen.
So having one gun primarily for enemy aircraft, that being a .303,
and one gun primarily for balloons, that being the 11mm, would have, I think, made a lot of sense.
And of course you could use them both in any circumstance.
So you'll see these in American use in that way.
Anyway, these guns, a couple hundred of them came back to the United States as surplus after the war.
There were a number of things that were done with them, they're kind of
interesting in that they're basically unfireable.
So most of these out there are missing a few parts, or have been deactivated.
And no one's ever really bothered to put them back together because
there is no 11mm Vickers ammunition available.
The links are virtually unavailable.
It's very cool that we were able to get four cartridges.
Like, this is the most of these cartridges I've ever seen in one place before.
So they exist primarily as simply historical curios like this one.
Hopefully you guys enjoyed the video.
Thanks for watching.
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