ID guns on these MCC trucks

[Mike K]

Can somebody ID the guns on these MCC CDSW's . Pic is in New Zealand .... So why didnt we get any of these vehicles

[Keith Webb]

Not a comment about the guns, but the first picture shows well how closely the bodies on the Canadian prototypes matched these Morrises.
Goes to reinforce what an amazing job was done by the joint design teams in Canada to adapt GM and Ford vehicles.

[Richard Coutts-Smith]

The pic is titled 18 pounder. Would that be a clue?
Rich.

[Ron Pier]

I just thought I'd post this picture of another Morris towing a gun. It's a MK2. 2 pounder like mine. I'll post a couple of pix in the 'GUN PARK'

Ron

[David_Hayward (RIP)]

I know nothing about guns but 18-pounders makes sense judging by the pre-war Canadian papers relating to the 1937-8 Ford-Scammell and Chevrolet-Scammell tractors. The drawings for the bodies were supplied to Ottawa from the Royal Arsenal in Woolwich so this explains why they are so alike.
As it turned-out the 6-wheeler gun tractor was destined not to proceed and by 1939 the 4x4 tractor was the preferred option.

[Mike Cecil]

Gun, QF, 18-pdr Mk.1(P).

ie, a WW1 era Mk.1 18-pdr, 'pneumaticised' by convesion to pneumatic wheel/tyre combinations with high-speed axle with ball-type wheel bearings.

A salient feature is the single pole-trail.

Mike C

[Mike Cecil]

correction: cone-and-roller type wheel bearings.

QF is Quick Firing: ie the means of obturation is the expansion of the brass shell case against the breech. Ammunition was fixed type.

Gun had a comparatively low range of the angle of fire (+/_ horizontal): quite a contrast to its replacement, the 25-pdr 'gun-howitzer', which was much more versatile.

Mike C

[chrisgrove]

Pole trail limits elevation - hence reduces the range! Nice pics of Martin Parry conversion.

Chris

[Mike Cecil]

Yes, that's partly true, but there comes a point of elevation with a fixed cartridge (like the 18pdr) where further increasing the elevation actually decreases the range. I agree that the single pole trail design limited the elevation in the 18pdrs case to only +16 degrees, which in turn meant that for the 18pdr cartridge, the maximum range attainable was also limited.

The main problems with the limited range of elevation (-5 to +16 degrees on the 18 pdr Mk1) were crest clearance (getting a round over elevated terrain) and the inability to elevate sufficiently for 'plunging fire', ie getting the round coming back to earth at a high angle, which was much more effective when bombarding emplacements and fortifications.

Mike C

[Mike K]

Wiki does it again:

http://en.wikipedia.org/wiki/Ordnance_QF_18_pounder

Nasty , the way the shell exploded, delivering a wave of lead/antimony bullets up to 300 yards away .

Mike

[Mike Cecil]

Yes, Mike: I've just read through it, and its a good coverage of the gun and ammunition. Not much reference to Australia (esp WW2 use in the ME and Pacific) but that's a minor point in the overall scheme of things.

The explosive action of the Shrap shell 'ejects' the balls/shot from the casing, which then falls to earth, often remaining intact. Many were subsequently souvenired, and thus it is probably the most commonly available variant of the 18pdr in collections because of that.

Mike C

[David Hardway]

Hmmmmmm i know these pics of the approx 10 Morris CDSW tractors to come to NZ there are remains of at least 5 still known to exist just not really enough to build a decent truck

Dave

[David Hardway]

Heres some more from the same sequence note the threadbare tyres on the limber

Dave

[Lang]

MikeC,

Good info as usual.

I think your info on reducing the range with elevation is suspect - you can't beat physics - 45deg is maximum range for any projectile, thrown rock, motorcycle jumping busses or garden hose. Shot-put and javelin athletes aim for an exact 45deg launch.

I seem to remember "howitzer" referred to a weapon capable of higher angles than 45deg - very useful for high crest clearance or tossing over a hill ie the shells go further and further as the gun gets to 45deg then start coming back in - try it with a garden hose. In theory, if you can get it high enough (mortars have no trouble) you can drop a shell down almost vertical behind a building 100 metres away - or maybe back down your own barrel!.

They had a reasonable range because they had quite a good muzzle velocity. For those whose memory needs jogging like mine these days, the weight of the projectile has absolutely nothing to do with its range. If we had a target at 100 metres a 22 aimed direct would hit it about 5 inches low, a heavier 243 would hit it about 1 inch low and an even heavier 18 pounder would hit it about 8 inches low. It is all to do with the time in the air while gravity is pulling them all down at 32 ft/sec/sec so velocity is king.

I can't figure out why they only had 16deg unless they were designed as a direct fire weapon - it would make them almost useless as an indirect fire support weapon. Any ideas? I suppose they came from an era where the commander still stood on a hill and directed the battle visually.

[Lang]

Just done a bit more research on the 18 pounder. The Kiwis were certainly sold a pup if they bought those early guns. Maybe they are an anti-tank unit?????

They were designed as a direct fire weapon and obviously upgraded to indirect fire as better sights were invented during the post Boer War period (quite amusingly the Brits chose a German manufacturer to make their sights). During WW1 they were soon upgraded to 30deg elevation and then 37deg as mentioned above by redesigning the trail..

I think the Kiwi buying committee were misunderstood by the Brits when they ordered guns for 'ndrct' fire.

[Mike Cecil]

That gave me a laugh, Lang!

I agree that velocity is 'king', and I don't think I was specific in mentioning the angle at which the fall of shot starts moving back: but I believe what I said was correct as stated.

Now take the 18pdr's successor, the 25-pdr, described as a 'gun-howitzer'. Although its max angle of elevation on carriages Mk.1 and 2 (and sub variants) was less than 45 degrees (actually a max of 40 degrees with spade embedded), the fall of shot could be varied by another factor: varying the charge weight (it was a semi-fixed cartridge), hence, varying the velocity. The combination of those two factors gave the weapon much greater flexibility: everything from 'lobbing' shells over tall hills at low velocity (indirect fire) to firing anti-tank shot direct on Charge Super (at max velocity). The Mk.3 carriage gave even greater ability to clear crests, being articulated to give an even greater max elevation well over 45 degrees.

Mike C

[RHClarke]

Gunners have never been constrained in the use of their field pieces by engineering/manufacturing specifications. Fixed max elevation on 18 Pounders and 25 pounders were overcame by digging in the trails (http://books.google.ca/books?id=oLge...g%20in&f=false see image at page 38). This changed the maximum ordinance or max height of a round and its overall range. The data for exceeding max elevation could not be found in its firing tables, but the fall of shot would be consistant making adjustment of artillery fire at high angle a reality.

Modern day howitzers (towed or tracked) have a greater ability to engage targets in "high angle" or in the "upper register" than their predecessors, but if you absolutley had to engage a target close to the gun position but hidden behind a high obstacle, you need only to request fire from another call sign (arty, armoured, attack helicopter or if they check out of the Holiday Inn on time, fast air support) that can reach out and touch the target.

[Lang]

MikeC,

I think most people are right when they praise the 25 pounder, which I understand used the 18 pounder as a basis for design.

The different charges were very convenient for range/approach angle variation. When I was a 17 year old kid in 11 Field Regiment they also said they liked to use minimum charge to reach the target to reduce barrel wear. As kids, we all loved to be the ones who burned the big heap of extra charge bags at the end of a shoot.

I used to hate it when they called out "Charge Super" (which was rare). When you pulled on the handle it was like being wacked over the head with a baseball bat. I saw stars every time!

As an aside, I would like to know where the higher angle/less range (below 45deg) theory comes from, I think it can't happen.

Lang

[Mike Cecil]

Lang,

To clarify, I didn't say that the 'higher angle/less range' could happen at less than 45 degrees. I simply stated that, for a fixed cartridge like the 18pdr, there comes a POINT where further increases in elevation cause a decrease in range. You later specified this to be 45 degrees, with which, all things being equal, I agree.

Mike C

[Local Chap]

Originally Posted by Mike Cecil

Lang,

To clarify, I didn't say that the 'higher angle/less range' could happen at less than 45 degrees. I simply stated that, for a fixed cartridge like the 18pdr, there comes a POINT where further increases in elevation cause a decrease in range. You later specified this to be 45 degrees, with which, all things being equal, I agree.

Mike C

The range of a artillery projectile is primarily dependant on the Muzzle Velocity, rather than the ammunition type being fixed or semi-fixed. The 4.7in AA gun (aka 28pdr) has a greater range than the 25pdr, and uses fixed ammunition. There are at least 2 recorded instances in the Aust Army during WW2 where 4.7in guns were used as field guns at a range beyond the 25pdr's (Milne Bay and Morotai). It did involve some co-operation between the crews, with Fd Gunners setting the fuzes and the AA Gunners calculating ranges and time of flight. The point that Mike has made is that the Semi-Fixed type offers far greater flexibility in controlling MV.

All guns have range tables that show range for elevation. For fixed types, this is a simple chart that shows elevation x = range y (with other variable calculations for bore wear, temperature, altitudes and in some cases windspeed!). For the 25pdr and 105mm (both of which use semi-fixed ammuntion), there is a separate range table for each charge (25pdr has Charge 1, C2, C3 and Super Charge, while 105mm has C1, C2, C3, C4, C5, C6, C7 and Super), and again each one is affected by variables. The 25pdr has effective range from 100yds on Charge One at zero deg to 13,900yds at 45 deg on Super for a gun in peak condition on a cool day at low altitude. For a gun with a worn bore, on a hot day at high altitude (all factors which affect MV), the max range drops to 12.300yds!

Interestingly, the table for 4.7in AA gives a maximum range of 20,600yds at 46 deg

[Lang]

MikeC,

I was not trying to enter a dispute with you Mike just read your first info regarding 18 pounders only going to 16 deg then mentioning they actually reduced range at higher angles because of fixed ammunition. I presumed you were suggesting much over the 16deg was the limit - I apologise for reading you wrong.

We now have established that 45deg is maximum range for any projectile whether fixed cartridge, variable cartridge or hand thrown and in fixed conditions velocity out of the barrel is all that counts for each individual shot. I suppose that is why when doing a concentrated shoot 4 identical guns, sitting within yards of each other with identical sight settings and shells flying through the same winds etc all have to have individual corrections to get everybody hitting the same spot.

You can hear the difference when you get the order "FIRE" and everyone goes within a micro-second of each other in one big explosion but half a minute later you hear in the distance Bang, Bang Bang Bang as the faster muzzle velocity shells sprint ahead of the rest.

As the members say above, once the gun variables are dealt with (temperature, wear, charge etc) and a muzzle velocity is established you start dealing with winds etc. Amazingly accurate over such huge distances but the calculations only get you in the ball park and we still are really firing Napoleonic cannon balls and correcting from what the FO sees by eye. We will never get first shot accuracy every time until we have field guns doing a Tomahawk Missile using GPS coordinates inside a "flying" shell itself.

[RHClarke]

Originally Posted by Lang

MikeC,.... We will never get first shot accuracy every time until we have field guns doing a Tomahawk Missile using GPS coordinates inside a "flying" shell itself.

http://www.defenseindustrydaily.com/...of-target-032/

"within 10 feet of target" - not bad considering the kill radius is over 30 meters.

[Marc van Aalderen]

Hi,

Here are some pics of the original WW1 18 Pdr. before conversion to modern rubber shoes. These were taken at Firepower, the Royal Artillery Museum in Woolwich Arsenal, UK. I find the projectiles very large compared with the cases. One would imagine the range to be limited because of that.



Cheers,

[Lang]

The article says they will roll out in 2006 - did it happen? If so they must be saving a bunch of ammunition in Afghanistan. Very effective as the bad guys don't have time to hide while the guns stab around the countryside like a blind man with a cane (the FO) before they get "on".

There is one drawback to all this progress - in a full-on war the other team have the same technology.

[RHClarke]

Originally Posted by Lang

...There is one drawback to all this progress - in a full-on war the other team have the same technology.

Yes, but our ammo won't be made in china.

[Mike Cecil]

Ooops.... just noticed a blunder in my previous post, when I stated:

: "varying the charge weight (it was a semi-fixed cartridge)".

Wrong: the 25 pdr is a Seperate cartridge, not semi-fixed. 105mm Howitzer is semi-fixed.

Sorry guys... I should know better!

Mike C

[Alex Blair (RIP)]

Originally Posted by Mike Cecil

Ooops.... just noticed a blunder in my previous post, when I stated:

: "varying the charge weight (it was a semi-fixed cartridge)".

Wrong: the 25 pdr is a Seperate cartridge, not semi-fixed. 105mm Howitzer is semi-fixed.

Sorry guys... I should know better!

Mike C

Mike..
You see that we were very tolerant of your "blunder"..and took advancing age into consideration...
(Keefy made me do it...!!LOL)

[Mike Cecil]

Thank you Alex...... we are all 'advancing' at the same rate (tick tock...)

.... now where did I put my medication and walking frame????

Mike C

[Alex Blair (RIP)]

Originally Posted by Mike Cecil

Thank you Alex...... we are all 'advancing' at the same rate (tick tock...)

.... now where did I put my medication and walking frame????

Mike C

Mike..
It is probably right next to my oxygen generator and puffers..ceegars and welding..paying for my sins committed when I was invincible..
Alex
(If you are in the Ottawa area PM me for phone number and we will organize a gather up at Gracies...standing offer for all visitors..CMP and MLU'ers)

[Mike Cecil]

Thanks Alex, will do.

Mike C