P36 vs Hurricane

[RCAFson]

ASI (mph) Hawk/Hurricane (time to bank 45degs)

200 2.2/1.3 seconds
250 2.3/1.4
300 2.7/1.5
350 4.0/1.6
390 5.2/1.9 seconds

(From Flying to the Limit)

 

[Shortround6]

I would note that the Hawk 75 was originally equipped with the experimental Wright R-1670 14 cylinder radial engine that went about 1170lbs. Used in a few other Curtiss prototypes the engine went nowhere was was replaced rather quickly by Wright Cyclone 9s in the planes that were using it. Wither the Army specified the use of the P&W R-1830 in the fighter competition that led to the purchase of the P-35 I don't know or if Curtiss thought the smaller diameter engine (compared to the Cyclone 9) offered better streamlining or if the P&W R-1830 was offering more power at that particular point in time than the Wright R-1820. They tended to swap back and forth quite a bit as to which was the more powerful. The R-1830 was always heavier though.
The US did get 30 six gun P-36Gs when they took over the last of 36 Hawk 75A-8s intended for Norway. These used Wright R-1820 engines that weighed about 1320lbs. These were commercial engines that were given a military designation and were never given a military power rating, just take-off and max continuous. The planes were given to Peru in 1943.

 

[fastmongrel]

I'd rather have 2 50's than 8 DRC (deer rifle caliber) machine guns

I dont think I would rather have 2 synchronised 1939 specification .50 Brownings over 8 .303 Brownings. The 1939 M2 when synchronised fired at around 450 rpm and there was no 2,900 fps Armour Piercing Incendiary ammo either, it was 2,600fps Tracer, AP or Ball. A 1941 model M2 A/N firing at 850rpm was reckoned to be 3 to 4 times more effective than a .303 Browning. A pair of 1940 M2 at 450rpm is going to be roughly equivalent to 4 or 5 .303 Brownings.

 

[fastmongrel]

I dont think I would rather have 2 synchronised 1939 specification .50 Brownings over 8 .303 Brownings. The 1939 M2 when synchronised fired at around 450 rpm and there was no 2,900 fps Armour Piercing Incendiary ammo either, it was 2,600fps Tracer, AP or Ball. A 1941 model M2 A/N firing at 850rpm was reckoned to be 3 to 4 times more effective than a .303 Browning. A pair of 1940 M2 at 450rpm is going to be roughly equivalent to 4 or 5 .303 Brownings.

Just found a table from Anthony Williams site WORLD WAR 2 FIGHTER GUN EFFECTIVENESS
The relevant info is interesting.
Hawker Hurricane Mk I 8x.303 Brownings is given a gunpower rating of 160
P40C 2 x .50 and 4 x .30 is given a gunpower rating of 163

 

[Greyman]

The Hurricane was never a 327 mph fighter in combat configuration. Operational examples in the BOB could not even hit 300 mph. Most topped out at 288 - 294 mph, and that was at full throttle, best height. We all know how long full throttle can be used, so most were basically 275 mph airplanes in combat trim, with a little "extra" if badly needed for a short time.

At least they were in the combat reports I have read and the books I have seen. The only 300+ mph Hurricanes I can recall were unarmed prototypes. The 327 mph variant was ONE mark in unarmed fitment, IIRC. The fastest fully armed, large production rtun version I can recall went 31 mph at the company trials. In service they lost a bit of speed and were down to sub-300 mph performance, too.

You gotta trust the eggheads at Boscombe Down and their 27-page report, not the two-line Squadron pilot anecdote. Some Flying Officer on operations looking at his airspeed indicator doesn't compare to the scientific approach taken at the A&AEE.

Wind correction? Position Error Correction? Other instrument error? I have a trial conducted by the AFDE (soon to be AFDU) in which a Hurricane and Defiant were flown in formation at the exact same speed and the difference in their ASI readings was 7 mph. Which direction were the errors, was the true ASI reading in-between? Who knows ...

For what it's worth, as far as the AFDE could tell that particular Hurricane made 317 mph at 17,400 feet. And that was the old 'slower' position error numbers for the Hurrie.

 

[Shortround6]

The British .303 was about 90% as powerful as the American .30-06. Main failing of the .303 in the BoB was more ammo availability related than power of the cartridge. Nowhere near enough AP .303 and nowhere near enough incendiary.

15 rounds per second from a pair of early fuselage .50s depends waaaaayyyy too much on the Golden BB vs 150 or so .303 bullets per second.

 

[Greg Boeser]

The Finns apparently used Hawk's 87 octane gasoline.
The bomb racks and light bomb tanks were removed as unnecessary.
Armament changed to 1 or 2 12.7 mm machine guns and two or four 7.7 mm Browning on wings.
Nickname is "Sussu" = Sweet heart, because the machine was easy and pleasant to fly.

Thanks, Lefa. That explains why the R-1830 is rated at 1065 bhp for Finnish aircraft. I was told that a few ground support missions were flown by LLV 14 and 16 before they surrendered their Hawks to LLV 32. Photos show the bomb racks still in place on many LLV 32 Hawks.

Here's a H-75A-4, possibly still with LLV 14 or 16.

 

[stona]

Main failing of the .303 in the BoB was more ammo availability related than power of the cartridge. Nowhere near enough AP .303 and nowhere near enough incendiary.
.

Exactly, during the BoB period typically three or four of the guns would be loaded with ball ammunition, which was of very limited capability, unless it hit the pilot/crew.
Later any .303 machine guns in fighters were loaded with incendiary and AP ammunition, to the exclusion of ball ammunition. There's a clue there
I've excluded tracer. If anyone can find a standard load for this I'd be interested!
Cheers
Steve

 

[fastmongrel]

The British .303 was about 90% as powerful as the American .30-06. Main failing of the .303 in the BoB was more ammo availability related than power of the cartridge. Nowhere near enough AP .303 and nowhere near enough incendiary.

15 rounds per second from a pair of early fuselage .50s depends waaaaayyyy too much on the Golden BB vs 150 or so .303 bullets per second.

Does anyone know if the RAF was using MkVII or MkVIII ammunition. The MkVIII designed to increase the range of the Vickers MMG and was a good bit more powerful than the MkVII it used Nitro Cellulose rather than Cordite and had a boat tailed bullet.

 

[fastmongrel]

Exactly, during the BoB period typically three or four of the guns would be loaded with ball ammunition, which was of very limited capability, unless it hit the pilot/crew.
Later any .303 machine guns in fighters were loaded with incendiary and AP ammunition, to the exclusion of ball ammunition. There's a clue there
I've excluded tracer. If anyone can find a standard load for this I'd be interested!
Cheers
Steve

From Anthony Williams website THE BATTLE OF BRITAIN

the initial RAF fighter loading was three guns loaded with ball, two with AP, two with Mk IV incendiary tracer and one with Mk VI incendiary.
Another source for the Battle of Britain armament gives four guns with ball, two with AP and two with incendiaries (presumably Mk VI) with four of the last 25 rounds being tracer (presumably Mk IV incendiary/tracer) to tell the pilot he was running out of ammunition. It is not clear why ball was used at all; presumably there was a shortage of the more effective loadings. (By 1942 the standard loading for fixed .303s was half loaded with AP and half with incendiary.)

 

[stona]

When the Mk IV ammunition was superceded some tracer, apart from that at the end of the belt to tell the pilot that his ammunition was expended, seems to have been included, at least as far as I can tell from gun camera footage. I've never found a ratio for this in fixed aerial machine guns.
Cheers
Steve

 

[Greyman]

As fastmongrel posted, during the Battle of France/Battle of Britain the ratio was 50% Ball, 25% AP, 25% Incendiary.

Ball ammunition was used because

• it was found to be broadly more destructive against light aircraft structure. Mostly due to a greater % of AP ammunition being deflected by aircraft skin at shallow angles
• general lack of armour of German aircraft
• heavier barrel wear of AP ammunition

At steep angles, of course, AP ammo was better vs. heavy fittings and naturally armour plate when (eventually) encountered. Incendiary was in low proportion due to the general unreliability of the type, and the RAF couldn't justify removing reliable ammo with a type that might not do its job in any particular burst.

After the Battle of Britain the RAF used a 50:50 AP:Incendiary ratio to meet the Luftwaffe's new armour and to take advantage of their new, better performing Mk.VI 'de Wilde' Incendiary.

Tracer was never part of a standard loading for Fighter Command except for a short period in 1939 when trouble was experienced with the Browning and the Mk.IV Incendiary.

All RAF ammunition used nitro cellulose (designated with a 'z' postfix, eg: .303 Mk.VIIz Ball), and didn't use the Mk.VIII round.

 

[fastmongrel]

and didn't use the Mk.VIII round.

I wonder why surely the 300 fps extra would be useful. Unless the boat tailed bullets were less destructive or in short supply.

 

[parsifal]

some basic home truths about zekes fighting P-40, P-39 and P-36s. none of these types did well against the Zeke at any stage in the war, even after the limitations of the Zeke was known and countermeasures worked out. The shoot and scoot tactics developed towards the end of 1942, basically reduced loss rates amongst the Allison engine fighters, not increased zeke loss rates. Zeke loss rates skyrocketed due to the radial types used against them, basically F4U, f4F and f6F. P-38s had such a marked speed advantage that they too tore into the Zekes with a vengeance. Losses to the older US types were never fantastic.

So whatever theoretical advantages you guys want to convince yourselves of over the Zeke with these old crates, it simply does not exist in the operational results.

 

[pinsog]

Ball ammunition was used because

• it was found to be broadly more destructive against light aircraft structure. Mostly due to a greater % of AP ammunition being deflected by aircraft skin at shallow angles
• general lack of armour of German aircraft
• heavier barrel wear of AP ammunition

At steep angles, of course, AP ammo was better vs. heavy fittings and naturally armour plate when (eventually) encountered. Incendiary was in low proportion due to the general unreliability of the type, and the RAF couldn't justify removing reliable ammo with a type that might not do its job in any particular burst.

[/QUOTE]

You said "RAF couldn't justify removing reliable ammo with a type that might not do its job in any particular burst"

How was the incendiary unreliable? Was in not firing at all or was the incendiary not doing its job on impact?

 

[pinsog]

The British .303 was about 90% as powerful as the American .30-06. Main failing of the .303 in the BoB was more ammo availability related than power of the cartridge. Nowhere near enough AP .303 and nowhere near enough incendiary.

15 rounds per second from a pair of early fuselage .50s depends waaaaayyyy too much on the Golden BB vs 150 or so .303 bullets per second.

The Russians were basically using 2 .50 Brownings against the Germans when they used the P39. They removed all the wing guns and I would imagine the 37mm was useless against a maneuvering 109 or 190 and only good for relatively non maneuvering bombers, so that leaves 2 50s. The Dauntless only had 2 50's and according to Lundstrom in The First Team it did well against everything except Zero's. The Dauntless pilots in the Guadalcanal campaign appeared to be extremely aggressive, picking off Japanese dive bombers, torpedo bombers and even a few of the large Japanese flying boats to the point it was actually annoying the Wildcats. He talked of Dauntless pilots accepting head on passes from Zero's and, since their guns were on the centerline and outranged the Zero's guns, they scored engine hits on the Zero and shot it down before they were in range of the Zero's weapons.

The only way I would want to fight with 30 caliber machine guns is if they were all concentrated in the nose. In fact, I think it was a mistake to arm the Whirlwind with 20mm cannon simply because they only had 60 round drum magazines. I read an article on the Whirlwind and it seemed like all the combat stories were "I pulled up behind German plane, began firing scored some hits, ran out of ammo, went home, enemy plane damaged". I would have armed the Whirlwind with 8 303 machine guns. That many guns that close to gather would have been devastating, like a saw, not much different than a 7.62 mini-gun.

 

[Greyman]

How was the incendiary unreliable? Was in not firing at all or was the incendiary not doing its job on impact?

Not doing its job, so to speak. You had to hit the relatively small area required to have the desired effect - then cross your fingers and hope said desired effect takes place. Whereas Ball ammunition was more liable to 'do its job' and over a greater volume of the enemy aircraft than Mk.IV Incendiary.

Interestingly, the RAF found that increasing the proportion of Ball ammunition actually increased the chance of the incendiary ammunition starting a fire in the enemy aircraft - I'm guessing due to the mass of ball ammunition chewing up tanks and plumbing to an extent that allowed an easier job for the Incendiary ammunition.

In other words 75% solid : 25% Mk.IV incendiary was better at starting fires than, say, 50% solid : 50% IV incendiary.

 

[Shortround6]

You have two differences between a Russian P-39 in 1942/43 and a Curtiss Hawk in 1940. One is that the 1942-43 machine guns had a higher cycle rate, although still much lower than wing guns, and the 2nd is that they had the M2 ammo instead of the M1 ammunition. an extra 250-280fpm of velocity. There may have been different proportions of ammo types? Not sure if the Russians got M8 MPI ammo or not, since the design was pretty much a copy of a Russian bullet for their own 12.7mm guns there wasn't much point in trying to keep it a secret.

Just how many Japanese planes did the Dauntless shoot down with cowl guns? 4? 7? 12 or none? Not claimed but actually shot down as listed as lost in Japanese records?

IF the wing guns are aimed at one spot (or small area) then at most practical fighting ranges it doesn't make a whole lot of difference is the guns are all in the nose or in the wings. Please work out the geometry for a 250 yd cross with guns 12 feet apart.

 

[pinsog]

Just how many Japanese planes did the Dauntless shoot down with cowl guns? 4? 7? 12 or none? Not claimed but actually shot down as listed as lost in Japanese records?

I have no idea how many were shot down vs how many were claimed, I'm sure you've read both of Lundstroms books and you would know that the Dauntless interceptions of the snoopers around the carrier (I can't remember which carrier and don't feel like looking it up) were pretty well confirmed when they exploded and burned all the way to the water like a meteor and could be seen by the whole task force. And, during the big fur ball when Hornet was lost and Enterprise was damaged, many of the returning Dauntless pilots piled right into the fight like they were flying Wildcats (they're aggressiveness stunned me when I read the second book. It seemed that the only enemy plane they had any respect for at all was a Zero, anything else to them was a target) They were aggressively shooting at anything with a red circle on it. Best guess on cyclic rate for Dauntless 50's? P39 50's?

And, obviously, the sample of any combat over the Pacific was tiny compared to the air battles that occurred around England, Germany and Russia.

 

[GregP]

Hey Fastmongrell,

Thanks for tghe table. His table is deeply flawed.

Follow his example. He says the first row shell has 5% Hei, so he multiplies by 1.5. But that SHOULD be 1.05, not 1.5.

105% is 1.05 and 150% is 1.5. So his numbers are WAY off.

Just FYI. I made my own table with teh correct multlplication and the results are startlingly different. Still, a great resource tghat CAN be coirrected to be actually useful.

- Greg