Maneuverability vs Speed

[pbehn]

That's why I assumed Bill meant best interceptor for the U.S.A.

We tended to make our planes a bit heavier than British planes of the same general variety. At least fighters, anyway. Not sure which was better overall, but the British Spits were always the cat's meow in performance, if a bit "delicate" by comparison.

The role of interceptor when first mooted in around 1935-6 was all about RoC and firepower. That was before Dowding system was devised. If the Spitfire had more endurance in terms of fuel and ammunition it would be of great advantage to Park and other commanders.

 

[Shortround6]

Two 12.7mm machine guns isn't a whole lot worse than a lot of Soviet fighters at that time. One 12.7 and one 20mm or one 7.62 and one 20mm were pretty common

The A6M was more heavily armed than most Soviet fighters in 1942.

It was a lot worse.
It is not just barrel count.

The Soviet 12.7mm gun was a bit more powerful than the US .50 cal and fired a bit faster (and didn't seem to loose quite as much to synchronization.

Japanese 12.7mm ammo is about 33-35.4 grams at 760M/sec for 9,800-10,600 joules of of ME. (Italian ammo was much the same)
Soviet 12.7mm ammo is about 52 grams (API) at 860M/sec for 19,200 joules of of ME.
US .50 cal is ammo is about 43 grams (AP) at 870 M/sec for 17,400 joules of ME.

Japanese 12.7mm gun was 23KG in weight and a rate of fire at 800-900rpm for a weight of fire of 485 grams per second (34.3 x 850rpm)
Soviet 12.7mm gun was 25KG in weight and a rate of fire at 900-1050rpm for a weight of fire of 845 grams per second (52 x 975rpm)
US .50 cal gun was 29KG in weight and a rate of fire at 750-850 rpm for a weight of fire of 574 grams per second (34.3 x 850rpm)

Rates of fire are unsynchronized and the Japanese and US guns suffered much worse than the Soviet gun.

The Japanese 20mm Type 99-1 used 128gram shells at 600M/sec for 23,000 Joules.
The Soviet 20mm ShVAK used 96-99 gram shells at 860M/sec for 35,500-36,600 Joules.

Japanese 12.7mm gun was 23-26 kg in weight and rate of fire at 520rpm for a weight of fire of 1,110 grams per second (128 x 520rpm)
Soviet 20mm gun was 42kg in weight and a rate of fire of 800rpm for a weight of fire of 1300 grams per second. (97.5 X 800rpm)

The higher velocity of the Soviet guns means that they are easier to deflection shoot with.

to round things out the Japanese 7.7 guns in the Zero were worth about 158 grams per sec and the 7.62 mm soviet guns were worth about 324 gram per second, both of these are unsynchronized but the Soviet guns had about 100 M/sec more velocity for a bit better punch and a bit easier aiming.

Until the A6M3 shows up the Zero had about 120 shells of 20mm ammo. (60 per gun)
Lagg-3 held 120 rounds of 20mm ammo.
The La-5 held 400 rounds of 20mm ammo. The Yak-1 & 7 held 120-140 rounds of 20mm ammo.

A fair amount of variation with the machineguns.
One 7.62
Two 7.62
One 12.7mm
One 7.62 + one 12.7
Two 12.7mm.
The one 12.7mm was fairly common. The 7.62mm gun was expensive to make. Lots of had fitting and supply could not keep up with demand.

 

[GregP]

People with an agenda rarely play fair. That's the way life operates most of the time.

If you're going into a competition and if you don't have the mindset of winning at almost any cost, you usually don't win. You see it military tests, basketball, football, war, etc. The plaque for second place isn't very prominent. So, if it is war, you'd best set out to obliterate the enemy because he surely is setting out to do the same to you. Once you have the upper hand, you can be merciful. Once the enemy has the upper hand, he/she usually isn't very merciful, and you have to count on that in order to keep the goal in mind: WIN.

 

[Reluctant Poster]

I just think most of the Air Combat in 1941-1943 was in North Africa / the Med, Russia, the Pacific, and China. There were a few 'big shows' like Dieppe, and they did some daylight bombing and raids like at Eindhoven. Channel Dash. Various Fw 190 jabo raids and so on. But there was fighting over the ground / naval war in these other Theaters, which is a bit more consequential in this period.

RAF Bomber Command begs to differ.

 

[Wild_Bill_Kelso]

RAF Bomber Command begs to differ.

I am well aware, but how many day-fighters were accompanying RAF Bomber Command on their raids?

 

[Thumpalumpacus]

Once you have the upper hand, you can be merciful.

Once you have the upper hand, you pursue victory. Mercy has nothing to do with it until you're rounding up prisoners.

When you have the upper hand, that's when you step on the gas.

 

[GregP]

Once you have the upper hand, you pursue victory. Mercy has nothing to do with it until you're rounding up prisoners.

When you have the upper hand, that's when you step on the gas.

See, what did I tell you ...

And, actually, it depends on what your objective is. If someone starts a war, your objective is to either win or get him/her to the peace table and talking. If you get the upper hand then, by all means, go ahead and win. If you don't, your objective usually shifts to the peace table to get the war to stop when it starts going badly for your civil population.

 

[PAT303]

Kind of makes one wonder how useful the XP-51F or G, or the P-51H would've been as an interceptor--since improving rate of climb was one of the biggest objectives of the lightweight Mustang program. But then again, it seems that the P-51D would've been quite useful in that role on light fuel and with 75" or 80" boost that happened later in the war.

I've always been skeptical of many of these tests, I'd like to see 5 in issue squadron aircraft flown and the average taken, just because one aircraft, and in some cases brand new ones at that test flown in perfect weather reaches a speed it doesn't mean the rest will, I feel many of these tests need to be taken with a grain of salt.

 

[PAT303]

The role of interceptor when first mooted in around 1935-6 was all about RoC and firepower. That was before Dowding system was devised. If the Spitfire had more endurance in terms of fuel and ammunition it would be of great advantage to Park and other commanders.

That's been my argument from day one, with more fuel RoC becomes less important with the added benefit of better tactical flexibility.

 

[GregP]

If someone is going to bomb your city (or base, etc.) and you have limited warning time, the ROC is more important than fuel. If you can't get to the enemy, he will bomb his target. If you CAN get to your enemy, then getting there with more fuel is the best option, assuming enough ammunition to make a difference.

So, ROC doesn't take a back seat to more fuel unless you can get to altitude in time to stop the bombing attack. If you can't get there in time, all the fuel and / or ammo doesn't count, at least for that particular attack.

 

[Juha3]

That's been my argument from day one, with more fuel RoC becomes less important with the added benefit of better tactical flexibility.

The FC did not see the situation that way. A slower climb rate would have meant standing patrols, which were seen as wearing planes down too much and consuming too much fuel and tiring the pilots. The idea was that only when the attackers had been spotted would the start order be given. Only at the end of the BoB did fighter bombers and relative fast Ju 88 attacks force the FC to use standing patrols on a larger scale.

 

[Elvis]

I would note here that many later war fighters were agile - the Fw 190 was one of the fastest rolling fighters of the war, and the P-51 was not too far behind it. The Spitfire had the remarkable turn rate and the LF versions had excellent roll too. Most of the best Soviet fighters were also very good at roll (La 5, Yak 3) and pretty good at turning as well.

Roll rate alone doesn't neccessarily make for a fighter with the agility of a Zero.
Look at the P-40. Superior roll rate to a lot of fighters, and yet NO ONE hails its agility as a fighter. Most just seem to harp on it being an overweight turd that couldn't fight its way out of a paper bag.

 

[Greg Boeser]

Roll rate alone doesn't neccessarily make for a fighter with the agility of a Zero.
Look at the P-40. Superior roll rate to a lot of fighters, and yet NO ONE hails its agility as a fighter. Most just seem to harp on it being an overweight turd that couldn't fight its way out of a paper bag.

The P-40 had a poor horsepower to weight ratio. Therefore it suffered in climbs and acceleration. But most agree it could outturn anything the Germans were flying.

 

[PAT303]

If someone is going to bomb your city (or base, etc.) and you have limited warning time, the ROC is more important than fuel. If you can't get to the enemy, he will bomb his target. If you CAN get to your enemy, then getting there with more fuel is the best option, assuming enough ammunition to make a difference.

So, ROC doesn't take a back seat to more fuel unless you can get to altitude in time to stop the bombing attack. If you can't get there in time, all the fuel and / or ammo doesn't count, at least for that particular attack.

Sorry but I disagree, the British could see the bombers forming up before they crossed the channel, they also tracked them right across into British airspace before scrambling the fighters at the last minute because they didn't have the fuel to do otherwise resulting in them almost always climbing up from underneath, numerous BoB pilots have stated this, with another 30G tank behind the seat the fighters could have launched earlier and been at altitude before the bombers crossed the channel or had time to climb higher still to engage the top fighter cover, not just that with another 20 minutes of fuel the fighters could have been vectored to better positions to attack instead of straight up, lastly the extra fuel wouldn't inhibit the fighting qualities of the Spitfire because it would be gone before entering combat, just like any other fighter with aux or drop tanks. The only time a fighter has too much fuel on board is if it's on fire.

 

[Wild_Bill_Kelso]

Roll rate alone doesn't neccessarily make for a fighter with the agility of a Zero.
Look at the P-40. Superior roll rate to a lot of fighters, and yet NO ONE hails its agility as a fighter. Most just seem to harp on it being an overweight turd that couldn't fight its way out of a paper bag.

Right... except almost all of the pilots who actually flew it lol

 

[PAT303]

Right... except almost all of the pilots who actually flew it lol

The P40 is the most underrated fighter of the war, as stated in another thread, it was the willys Jeep of fighters.

 

[Wild_Bill_Kelso]

The P-40 had a poor horsepower to weight ratio. Therefore it suffered in climbs and acceleration. But most agree it could outturn anything the Germans were flying.

That really depended on the model, but basically this was an exaggeration too. It was a bit too heavy and didn't have a great climb rate, but the only real significant limitation was the altitude ceiling due to the single speed, single stage supercharger. The rest of that is basically late 20th Century legends.

 

[Wild_Bill_Kelso]

The P40 is the most underrated fighter of the war, as stated in another thread, it was the willys Jeep of fighters.

I don't know if it's the most underrated, but it definitely is in kind of an underdog position vis a vis postwar reputation vs during-the-war outcomes. It did a lot better than most people realize.

Several other underdogs also compete for the title though...

 

[Shortround6]

Radar and the "class of 36" (OK, Nov 1935 and March of 1936) crossed over.
You not only had the problem of developing the radar itself but figuring out how to use it.
If the radar units cannot transmit or relay the information to the defending fighters it doesn't do much good.
Until you get the radar ground control system in place and trained you have to design and build older style fighters (fast climb) incase the war comes early and/or the radar and ground control system does not work.
Of course the British shot themselves in the foot with the fixed pitch props so the Class of 36 to over 9 minutes to reach 20,000ft. Which means even a 180mph bomber can cover over 27 miles while an already warmed up aircraft takes off and climbs to 20,000ft. BTW the Spitfire will end it's climb at just under 180mph (best climb speed) and while need several more minutes to work up to a higher speed and actually intercept the bombers.
Some of the 2 pitch prop planes took almost 11.5 minutes to reach 20,000ft. Adding fuel and giving the bombers another couple of minutes (14 minutes = 42 miles/180mph bomber. 210mph bomber can cover 49 miles).

Fitting the constant speed props cut the climb to under 8 minutes.

But you don't get to go back to 1935/36 and design British fighters to have Constant speed props that allow them to take-off and climb with the bigger the fuel load.
The Hurricane and Spitfire were both designed to take-off with the wooden fixed pitch props from existing airfields.
The 2 pitch prop cut the take off run by about 100yds (76%) and the distance to 50 ft by 300yds ((62%)
The constant speed props improved things even more but the fitting of basic armor and rudimentary self sealing and better radios and equipment (like receiver for blind landing approach) Cut into the performance a bit.

Now the crappy field performance of the class of 36 came in handy in later years when they used them as carrier fighters with little modification. If they had been designed with CS props in 1936 one wonders if they would have been given small wings for a bit more speed but less growth.

 

[Shortround6]

single speed, single stage supercharger.

The OK for 1940 supercharger but failed to improve supercharger over the next 3 years.

Spitfire V used single speed supercharger and the Spitfire VI used a single speed, single stage supercharger (granted they didn't build very many of them)
The Spitfire VI had a pressure cabin, extend wings, 4 bladed prop, 364mph at 22,000ft and a service ceiling of 40,000ft. All with a single speed, single stage supercharger.

But Hooker was already working on the two speed, two stage supercharger.

There was no real magic about multi-speed superchargers. But they needed to be big enough to get the job done. Using a small impeller was not going to get the job done no matter how many speeds you used.

The P-40 had a poor horsepower to weight ratio.

Correct.
Nobody else was trying to use an 8300-8500lb fighter with a 1150hp engine.
Once it got above 12-13,000ft on the D-E-K s that is all the power you had,
and once of got above 17,000ft (in level flight) you had 1125-1150hp on the M & Ns.

http://www.wwiiaircraftperformance.org/P-40/A29-412-climb-WEP.jpg

This is for the stripped P-40N-1, 4 guns, no electric start, forward wing tank removed, etc.

you can put lipstick on a pig, The pig may be able to move pretty quick for a short distance. It is still a pig.