wuzak
Captain
They only had to deal with 20mm, 30mm, 37mm (used in Bf 110 and Ju 88 for attacking bombers BK 3,7 - Wikipedia), 50mm (in limited use Rheinmetall BK-5 - Wikipedia), rockets, flak and bombs!
50 cal (high rate of fire) vs 20mm cannon (hitting power)
- Thread starter grampi
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They only had to deal with 20mm, 30mm, 37mm (used in Bf 110 and Ju 88 for attacking bombers BK 3,7 - Wikipedia), 50mm (in limited use Rheinmetall BK-5 - Wikipedia), rockets, flak and bombs!
If you read through the battle of Britain thread a very large proportion of Bf109's didn't have armour fitted so the .303's were still and were very effective.
The British experience with the Hispano on the Typhoon fighter was that the 4 Hispano Mk 2 guns slowed the aircraft down significantly. Fairings were developed but these only lessened the significant speed loss. The Hispano Mk 2 was an enormous weapon almost twice the length of the 50 caliber M2. It was as long as the long barreled german 30mm Mk 103.
The solution was to shorten the barrel and surrender some velocity and these Hispano Mk V appeared in the tempest.
Typhoon probably could have carried 8 x 50 calibre M2 Browning fully in the wings.
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He did say .50 Cal gun so I assumed he was talking about the browning's being flush with the leading edge.
Yes, 12 .303s. FWIW, the Hurricane IIB also carried 12 Brownings.
From here:
Cleaning up of Typhoon 1.
Level speeds of production aircraft:- Full tests have been done at Gloster on the level speeds of 4 recent production aircraft of average finish. The maximum level speeds obtained were:
Typhoon 1A. R.7914 397.5 m.p.h. at 20,500 ft. F.S. 385 m.p.h. at 8,400 ft. M.S.
Typhoon 1A. R. 7869 396.5 m.p.h. at 20,100 ft. F.S. 379 m.p.h. at 8,000 ft. M.S.
Typhoon 1B. R. 8650 393 m.p.h. at 20,800 ft. F.S. 382 m.p.h. at 8,800 ft. M.S.
Typhoon 1B. R. 8636 392 m.p.h. at 20,000 ft. F.S. 379 m.p.h. at 8,200 ft. M.S.
1A being the 12 Brownings version, 1B being with 4 Hispano IIs. Under 5 mph speed loss on average for the cannon-armed Typhoon is hardly significant.
About the size of Hisso II - the 'no free lunch' rule applies. When introduced, it was the most powerful airborne weapon intended to fight other aircraft. It was not enormous, 4 fitted in the thin wing of Spitfire.
Shortening of the cannons' barrels was not something Typhoon needed, it have had more than enough power to cater for that. Typhoon needed a number of changes that were not related to armament in order to succeed.
Now that you say it, I did know that but completely forgot it.
The Mk 103 30mm was akin to the 37mm M9 in that it had a high muzzle velocity, but, like the M9, it was large and heavy. Germany was stuck with a majority of small fighters (109 & 190) or some clumsy fighters (110, 210, 410) for the most part. As a weapons system a P-63D would have been a problem for the USAAF. Just my opinion.
And some carried the Vickers 40mm for ground attack. I remember buying the 1/48th scale model (Monogram I think, maybe Revel) as a kid, and trying to figure out if I could put all the armament options on the plane at the same time! LOL
"Under 5 mph speed loss on average for the cannon-armed Typhoon is hardly significant."
5mph is not significant unless the 392-393mph Typhoon IB comes into contact with the 408-410mph Fw 190A5 at 20,000ft. Fortunately for the RAF the Sabre engine's power improved.
Speed loss occurs in trifles: gun ports, wheel well covers., retractable tail wheels, gaps in the radiator etc.
The barrel length of the Hispano II became more of an issue on the Tempest (due to its slimmer wings and higher targeted speed) and the Spitfire F22/F24 series which both needed the short barrelled Hispano V.
The gun was troublesome in wing installations. The US version which used a slightly different cartridge never became reliable enough to put into service despite millions of rounds of ammunition being produced.
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The Typhoon had a lot more power and a lot more, drag in part because of its thick wings but those wings could hold the cannon without having blisters.
Most of the manufacturers were allowed for 3% variation on speed for production version of ww2 fighters. At ~400 mph that means 12 mph difference between the best and worst performing 'specimen' - thus 5 mph speed loss due to massive increase of firepower was nothing.
Speed losses do happen on trivialities, however Typhoon was loosing a lot because of it's wing being of big TtC ratio and of outdated profile.
Who said that Tempest or Spitfire F22/24 needed the short barreled Hispano V?
Hispano worked in Hurricane and Typhoon. After initial problems, it also worked on Spitfire.
US Hispano have had a problem both with ammo and chamber length.
Main problem with Hispano was that it was lagging behind Oerlikon's cannons for several years.
Why did Supermarine fit shortened Hispano V to the Spitfire F22/F24? We know that Spitfires from the Mk XVII down had handling problems with 4 full length Hispano 2
Why did Hawker convert the Tempest V from Hispano 2 to Hispano 5. Hint because long barrel units were 5 mph slower at the same altitude and nearly 7 at optimum altitude. Had the Hispano V been available they wuld have used it in a heat beat.
As far as scatter goes I don't accept it. These were airframes that were carefully inspected for development testing. We have a consistent advantage to the 12 x Browning Typhoon in speed over the 4 Hispano V Typhoon.
If it wasn't necessary why did the RAF, Hawkers, RAE waste their time putting in an weapon with inferior ballistics? The Hispano V lost 5% muzzle velocity, 10% kinetic energy and about the same 10% loss in armour penetration.
The weapon clearly was powerful but gas operated mechanisms are known to be finicky to develop and maintain.
The Oerlikon Mechanism API mechanism and that of the MG151 were recoil operated. The non locking bolt was heavy but served to buffer recoil which helped keep installed weight down. The MG151 was designed for synchronisation from the start.
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Supermarine and Hawker fitted the Hispano V on their fighter because the Hispano V was now available, and Hispano II was being phased out production. It offered 750 rd/min* vs. 600 rd/min for the Mk.II - so basically it was a firepower of 5 Mk.IIs for weight penalty of 3.5 Mk.IIs.
Problem with, typically, Spitfire V lugging around 4 cannons was lack of engine power for such a heavy battery. Similar problem was shared by many P-40s, P-39s and Fw 190As.
The no free lunch rule applies as ever - 5 mph speed loss was diminutive price to pay for huge increase of firepower. The Fw 190A lost same amount of speed when it swapped the fuselage LMGs with HMGs, for a very small % of increase of total firepower. Some aircraft required gondolas when wanting to go from 1 cannon to 2 or 3, with a major performance loss.
Armour penetration & kinetic energy was not high on the RAF's list. Increase of rate of fire, while saving close to 80 lbs per 4-barreled installation, was high on the priority list. Muzzle velocity of 840 m/s was still higher than what German, Soviet or Japanese 20mm cannons offered.
(my bold)
Don't post misinformation.
Source for MG 151 having a non-locking bolt? What kept the installed weight down for MG 151 was that it was not firing a really powerful cartridge vs. what Hispano used.
*in a lot of places the 800 rd/min is quoted for Hisso V
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Snautzer01
Honourably banned
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A.G. Williams
Airman 1st Class
- 182
- Oct 10, 2020
That isn't the 20 mm MG 151, it's the 7.9 mm MG 15 - no relation.
Snautzer01
Honourably banned
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- Mar 26, 2007
ok what does mg 151/20 stands for then?
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Shortround6
Major General
Yes the Hispano's were big.
Hispano's were a hybrid gun. They used a combination of gas and recoil. The shorter lighter barrel helped with the increase in the rate of fire.
A.G. Williams
Airman 1st Class
- 182
- Oct 10, 2020
Oh, OK - the link opened straight into MG 15 for me.
