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One pass = two tanks!Hold my beer...View attachment 847464 Not just one, but TWO 37mm cannon!
Both guns have potential. The problem is the 1939 aircraft.
For our 1939/40 aircraft with 1939/40 engines we run into the problem of getting the guns off the ground and not being total sitting ducks while carrying them.
As a guide the Ju-87G used a a 1400hp Jumo 211J and is not known for spritely performance
This is why I've suggested making a 2-engined tank buster - there is enough of oopmh to carry the hefty guns around, plus the protection for the squishy stuff. The area of engines is far smaller than the area of the whole aircraft, that were typically (Ju 87, Battle, Potez 63 etc) offering 30-40 sqm to the gunners, depending on the angle.Using two normal sized 9 cylinder engines gives the AA gunners a large target. (about 1.5 sq meters each instead of 0.71 sq meters of the GR 14M engines on the Hs 129).
The weight of the MK 101 at 180 kg includes a full 30 rd drum.German C30/L....................................................64........................................300-350....................................................48,000(?)....................................100 round drum
German KwK 38(AA gun) ...........................57-71..........................................450..........................................................48,000(?)...................................20 round box
German MK 101...............................................180............................................230......................................................130-140,000...............................30 drum
German BK 3.7..................................................295............................................160..........................................................218,000......................................6-12 round strip
I don't know why the 2pdr pom pom shows up in these threads.British can have an A/C powered by two Mercury engines, the pointy end perhaps be the HV 2pdr pom pom.
A lot does depend on the angle. Aircraft approaching a target (or departing) offer much smaller targets than full belly shots but such shots don't require anywhere near as much lead.The area of engines is far smaller than the area of the whole aircraft, that were typically (Ju 87, Battle, Potez 63 etc) offering 30-40 sqm to the gunners, depending on the angle.
Thank you for the correctionThe weight of the MK 101 at 180 kg includes a full 30 rd drum.
Gun itself was at 140 kg.
The last sentences quoted there are underscoring the issue: timing. It is far better to have an imperfect gun in squadron service, than to gamble on a new gun to show up in the nick of time.I don't know why the 2pdr pom pom shows up in these threads.
Even without water it was a heavy gun, somewhere in the 250-290kg range depending on model and if water is included. Which explains the Vickers S gun and the RR BH gun. They were 75-10kg lighter.
It didn't fire any faster (or were within 10%) than the newer guns, despite the belt feed, they tended to jam a lot and required a lot of maintenance.
The Vickers S gun was modernized/improved 1 1/2 pounder C.O.W gun from WW I and they stopped production of those in 1918/19 and out of the 76 made (?) only 45 remained. They weren't worth fooling with due to old/limited ammo and need to change from the 5 round feed system.
The Vickers S gun project started in 1936 but it took until March 1940 for ground firing tests to begin. More urgency might have speeded things a bit? But getting squadrons in service by May/June of 1940?
The 25.4mm gun is indeed interesting.The 25.4mm was only sold to Argentina and the shell weight and velocity was within a few percent of the French Hotchkiss 25mm AA gun. It may have had a few advantages but they are hard to see, the Vickers gun was about 10kg heavier (around 10%) fired about 10% slower (200rpm vs 220rpm) and used 10 round magazines instead of 15. The last was probably the easiest to fix on both guns for aircraft use.
Both the Vickers and Hotchkiss were under 1/2 the weight of a 2pdr pom pom and the German 30mm MK 101, as noted by Tomo, was 140kg and really shows up the problem of trying to use the 2pdr pom pom.
A lot does depend on the angle. Aircraft approaching a target (or departing) offer much smaller targets than full belly shots but such shots don't require anywhere near as much lead.
Small caliber hits in wing tips or other empty spaces may create work for ground crews but often do not cripple the plane. Planes can survive some small caliber hits to engines but things get a lot iffier. Radials can survive a lot but hit's to the crankcases often mean oil leaks. Engine may stay running for 20 minutes or longer, depends on oil supply. Engine may stay running after hit takes out a pushrod or valve rocker arm. Power of 8 cylinders and not 9?
Very true.Advantage of just about any anti-tank airplane (except for those fighting the Germans) in 1939-40 is just about every army except the Germans had really, really really poor AA guns in 1940. Actually some of the guns were not really that bad. They were just very, very, very rare.
Chances of getting a Blenheim "lite" to swan about the battlefield looking for tanks when CC couldn't get Blenheims to swan about over the ocean/seas looking for U-boats is pretty low. Blenheims were needed for bombing German factories
Yes we know how that worked out and this is a "what if" so we can change doctrine.
The last sentences quoted there are underscoring the issue: timing. It is far better to have an imperfect gun in squadron service, than to gamble on a new gun to show up in the nick of time.
A 2-engined attacker (and the engines can be the yesterday's types) will have a much easier time with two pom-poms than the Ju 87 with two almost equally heavy BK 3.7s. Or the Hurricane I of 1940 with two Class S guns.
These two statements are at somewhat cross purposes.The tank buster will need to be a much smaller aircraft. Talk Mercury-powered Whirlwind, or something like the IMAM Ro.57. I'd suggest that the A/C is not bigger than the Ki 45 or Ki 46 -
HiThese two statements are at somewhat cross purposes.
Two 2pdr pom pom guns are a bit heavier than the bombload of the Blenheim. A single 2pdr Pom-pom is heavier than four 20mm Hispano guns. Whirlwinds needed a sizable runway, not as bad was originally feared but larger than most RAF (or French?) normal fighter fields.
A Hurricane I in 1940 is not a candidate for two Class S guns, even with a constant speed prop and the supercharger gears from a Fulmar
Engine is around 200hp weaker than the engine used in the Hurricane IID.
If you want close support aircraft flying out of forward fields you need aircraft that will operate out the fields you have or can expect to have in 1939/40. Not the fields they had in 1942-44.
As a caution the numbers for a Curtiss P-40B at 7352lbs (120 US gal fuel) were 1350ft (450yds) for take off to 50ft and landing was 1400ft (Curtiss figures, much better than Army figures for the P-40D/E) Obviously you want more room in case of errors or weather. The Blenheim was practically an STOL machine. Blenehim I (12500lbs) needed 296yds for the take-off run (not to 50 ft)
German 37mm gun was heavy. It also fired about 50-60 faster than the 2pdr pom pom.
Now a real question is if any of these 'attack' aircraft get self-seal tanks or armor/BP glass. The Germans were asking for it in the 1939 prototypes, Not sure where the British and French stood before Sept 1939. Don't think they put much, if any, in the Blenheims, Battles and Lysanders shot down in droves in France.
For the British the easiest/fastest solution (not the best) is either the Blenheim or the Battle. Available airframe (or production facilities) with good short field performance and decent load carrying (with modified engines).
I don't know how to measure the success of the Ju 87Gs... Most of their operational history was during the Red Army offensives, and their "kills" remained on the Soviet controlled territory.The Ju87G and Hs129 had great success in defeating Soviet AFVs by either attacking from the rear or top-down attacks.
If our early war ground attack aircraft follows this tactic, it should do well.
This requirement is tricky. Tank guns and tank armour increased quite a lot in size and thickness throughout the war. Weapons that worked early in the war did not work later in the war. Consider all the weapons like the .55 calibre Boys anti-tank rifle that were effective early in the war. Late in the war, the Stalin tanks had a 122mm cannon and 120mm of armour in front. A 1939/40 tank buster would quickly become obsolete.Looking for a possible & plausible what-if aircraft types for the different air forces/services. The aircraft, developed from 1936-37, needs to have sufficient weaponry to badly harm a tank that is expected to appear on the battlefield of 1939-40 (so a 20mm autocannon might and might not be enough), some sort of protection at least for the pilot since one can expect a lot of automatic weapons to be trained against the A/C. If the A/C can also do good against other land targets, like the infantry or the non-armored vehicles in the open, the better.
Engine choice - whatever the respective country makes, even the 2nd rate engines should do. A plausible mod of an existing engine is okay. If an easily available foreign engine can be used as an alternative, that's a plus. Use two engines if needed. A rear gunner is nice to have, but not mandatory. Design needs to be adopted for series production in the country of origin.
Weapons - a good gun is a must. If the off-the-shelf gun can fit, even with some modifications - great. Otherwise, whip up a plausible alternative. Ammo can use some love, there is no need to remain on the plain AP shot.
Sprinkle with MGs and bomb racks to the taste, but not in such quantity/weight that other features take a back seat, like a good main gun(s), handling and protection.
Speed is not of a concern.
The A/C must be of a modern layout (a monoplane with enclosed cockpit, basically).
For the British needs combined with the time specified in this thread, Hispano is too late to matter, even though it will be perfect against the best part of the German tanks in 1939-40. The 2pdr HV might just fit in the time specified, inter-service rivalry and needs aside.These two statements are at somewhat cross purposes.
Two 2pdr pom pom guns are a bit heavier than the bombload of the Blenheim. A single 2pdr Pom-pom is heavier than four 20mm Hispano guns. Whirlwinds needed a sizable runway, not as bad was originally feared but larger than most RAF (or French?) normal fighter fields.
There is a 2-4 year period specified, so there is no burning need to just slap the guns on something for the next week.For the British the easiest/fastest solution (not the best) is either the Blenheim or the Battle. Available airframe (or production facilities) with good short field performance and decent load carrying (with modified engines).
I need to find a copy of that bookHi
I am sure the question of armour on British aircraft during 1939-40 has been discussed before. A book that may help on this question is:
View attachment 848254
Some extracts for some of the period in question follows:
View attachment 848256
View attachment 848257
View attachment 848258
View attachment 848259
View attachment 848260
The armour was being fitted for air fighting not for ground attack of course, frontal armour for fighters was initially fitted to protect them from return fire from bomber formations.
Heavy armour to protect aircraft from AA fire when on ground attack missions does have effects on aircraft performance and more powerful engines are required. It also appears that during WW2 the use of relatively 'heavy' (and slower firing) guns for anti-tank use from aircraft worked best in desert or open steppe environments, less well in rather more close country with woods, forest, hedgerows, buildings etc., rather less time to line up and get rounds on target to an extent. Not to mention the ability to operate when air superiority could not be guarantied (JU87s did not fare well during the BoB for example despite 'success' during the BoF).
I hope that is of use.
Mike
For '39/40, how about the French Hispano cannon? This was already mounted on Morane-Saulnier M.S.406s, which were available in significant numbers. This would quickly become obsolete as a tank busting weapon, but you are talking about '39/40. This is simply a matter of switching from air superiority to ground attack. The French would quickly add armour if they somehow stayed in the war.For the British needs combined with the time specified in this thread, Hispano is too late to matter, even though it will be perfect against the best part of the German tanks in 1939-40. The 2pdr HV might just fit in the time specified, inter-service rivalry and needs aside.
A not-Whirlwind that has Mercuries instead of Peregrines saves 270 lbs in dry engine weight, as well as 500+ lbs of liquid cooling system. With that said, I'm not against a Fw187- or Ki-45-sized tanks buster, to further help with wing loading.
There is a 2-4 year period specified, so there is no burning need to just slap the guns on something for the next week.
If the 25.4 mm gun is available, British can try with Hurricane, Defiant, Henley, even the Gloster F.5/34 or the MB.2. Cut some dead wood so there is enough of production square footage, men and material to make these.
Yes, RAF will need the change of heart for the tank-busting aircraft to work out in early ww2, the 'battlefield aviation' is badly down on their priority list, and so is the cooperation between the different branches of the RAF, as well as with RAF and Army aviation.
406s are front line aircraft. How 'bout repurposing those obsolete D 510s?For '39/40, how about the French Hispano cannon? This was already mounted on Morane-Saulnier M.S.406s, which were available in significant numbers. This would quickly become obsolete as a tank busting weapon, but you are talking about '39/40. This is simply a matter of switching from air superiority to ground attack. The French would quickly add armour if they somehow stayed in the war.
The 2pdr HV was introduced in 1938. It is still a crappy gun to use an airplane although with only around 12-15 rounds it will probably go through the available ammo without jammingFor the British needs combined with the time specified in this thread, Hispano is too late to matter, even though it will be perfect against the best part of the German tanks in 1939-40. The 2pdr HV might just fit in the time specified, inter-service rivalry and needs aside.
Blenhiem I had wing loading of 27lbs/sq/ft. The Blenhiem IV was 30.7lbs/sq/ft and a clean Whirlwind was over 40lbs/sq/ft. The Ki-45 both late and sort of squishy. Early ones had the wing loading you are looking for. Later ones????A not-Whirlwind that has Mercuries instead of Peregrines saves 270 lbs in dry engine weight, as well as 500+ lbs of liquid cooling system. With that said, I'm not against a Fw187- or Ki-45-sized tanks buster, to further help with wing loading.
This gets a little squishy also, gun existed in right time period, The Argentine cruiser that used them was built from 1936-39 and AA guns can be added late in construction. As noted earlier the existing guns fired at 200rpm and used 10 round boxes. There seems to have been a proposal to mount a pair in the Spitfire in 1938 using 30 round drums. I have no idea if this went any further than napkin doodling. The Argentinians got 12 guns on 6 twin mounts so it was hardly a production item. It was powerful for the time but AP capability is unknown (only HE ammo?) and as noted earlier, it is 127kg. How much could be shaved off??? but over twice as heavy as a 20mm Hispano although a bit lighter than 2pdr S gun.If the 25.4 mm gun is available,
Can we please, please, PLEASE stop trying to drag the Gloster F.5/34 and MB.2 in many of these hypothetical "What ifs" about 1930s British aviation. They had few, if any, redeeming qualities as actual aircraft. Actual performance levels may not be what is often quoted. Certain construction features may have had merit but they not in the front ranks of aerodynamics.British can try with Hurricane, Defiant, Henley, even the Gloster F.5/34 or the MB.2. Cut some dead wood so there is enough of production square footage, men and material to make these.
406s are front line aircraft. How 'bout repurposing those obsolete D 510s?