Author Topic: Improve the P-47 (Read 12806 times)

Angus · « **Reply #105 on:** October 08, 2006, 08:05:23 AM »

I have one comparison of armament from a RAF pilot who went from Spit V and IX (4x.303 + 2x 20mm) to a P51C. (4x.50).
His feeling was tha it was a great stepdown in firepower.

gripen · « **Reply #106 on:** October 08, 2006, 04:20:39 PM »

Angus,
That was certainly a stepdown in firepower, but that does not mean that 4 x 12,7mm was somehow ineffective against the German fighters; 2 x 20mm would have been better but the combat record of the P-51B shows that 12,7mm MGs did pretty well after all. If they have been facing really well protected planes like the Il-2, the situation might had been different.

Pilot's comments on weapons seem to depend quite much on what kind of enemies they were facing and also what other planes pilots have flown. As an example Eric Brown started his combat career with the Sea Gladiator and other early war FAA fighters were the Fulmar and the Sea Hurricane so weapons of the Martlet were seen as a great improvement. In addition the good results against German planes seem to support Brown's opinion.

Notable thing is that I have not been able find any negative pilot comment on the weapons of the P-47; generally all comments seem to be more or less praising. And the combat record of the P-47 is pretty good so there is not much reason to believe that cannons would have caused a large improvement.

gripen

Oldman731 · « **Reply #107 on:** October 08, 2006, 05:34:39 PM »

Quote

Originally posted by gripen
Notable thing is that I have not been able find any negative pilot comment on the weapons of the P-47; generally all comments seem to be more or less praising. And the combat record of the P-47 is pretty good so there is not much reason to believe that cannons would have caused a large improvement.

gripen

Agreed. Statistics aside, US pilots seem to have been uniformly satisfied with their armament, and I have encountered reports from at least a couple of Germans who feared the P-47 because of its guns.

- oldman

Overlag · « **Reply #108 on:** October 08, 2006, 06:31:19 PM »

Quote

Originally posted by Oldman731
Agreed. Statistics aside, US pilots seem to have been uniformly satisfied with their armament, and I have encountered reports from at least a couple of Germans who feared the P-47 because of its guns.

- oldman

the problem is, people have the AH mindset. In AH, you have to blow the plane out of the sky to "win". hence why canons are seen as the only way by some.

in WWII, deep over Germany, just getting those 109/190s to disengage the bombers was enough to "win"...... a few pings from 8x50s would sure do that......

HoHun · « **Reply #109 on:** October 08, 2006, 06:36:57 PM »

Hi Oldman,

>Statistics aside, US pilots seem to have been uniformly satisfied with their armament, and I have encountered reports from at least a couple of Germans who feared the P-47 because of its guns.

Talking about the US pilots who apparently were satisfied, I'm sure that's because they were never given the choice between eight heavy (indeed) machine guns, or two cannon and the weight of their mount 684 lbs down.

You can have your crew chief tuning the machine for a year, and he will still fail to match the performance gain from the weapon change. The weight advantage takes the run-of-the-mill P-47D-25 half the way down to the P-47M "racer's" light weight configuration.

(It's also telling that 9th Air Force P-47 pilots refused the installation of rear warning radars, since they felt that 50 lbs of extra weight were too much. Now extrapolate that reaction to 684 lbs ... :-)

You're probably aware of the WW2 saying: "The Mustang does everything the Spitfire does, too, but the Mustang does it over Berlin."

Well, re-configure the P-47 with 2x Hispano cannon and some internal tankage, and the Thunderbolt "does it over Schweinfurt".

I think it's quite difficult to look at the greatest defeat the 8th Air Force ever suffered (and they suffered it twice) without reaching the conclusion that their escort fighters were somehow lacking. Very likely, this was 8th Air Force thought, for they replaced the the P-47 with the P-51.

The title of this thread is "Improve the P-47", and I have not seen any suggestion that would have yielded a greater improvement than simply exchanging the US gun for a model the British were already using with great success.

Regards,

Henning (HoHun)

HoHun · « **Reply #110 on:** October 08, 2006, 06:43:48 PM »

Hi Overlag,

>in WWII, deep over Germany, just getting those 109/190s to disengage the bombers was enough to "win"...... a few pings from 8x50s would sure do that......

Actually, the air war agaist the Luftwaffe was not won until the USAAF fighters were "unleashed" from close escort duties and actively hunted down and destroyed the Luftwaffe interceptors.

Not that there is much to choose between 8x 12.7 mm and 2x 20 mm firepower-wise - but the lighter cannon battery will leave you with more fuel for the hunt.

Regards,

Henning (HoHun)

Overlag · « **Reply #111 on:** October 08, 2006, 07:37:15 PM »

i didnt mean the overall winning of the war. The russians did that.....

i ment that the p47 was, mostly a bomber escort. Its job was to escort bombers, and protect them from fighters. Just getting them to break off was enough to forfill that plan.

sure, the ground attack/vulching the americans did of german bases would be better suited to a cannon version P47, but the escort one id rather have 6-8 50s.

also with 6-8 guns, if one jams, its not so much of a problem, but if that was a plane with only 4 cannons......

HoHun · « **Reply #112 on:** October 08, 2006, 07:47:57 PM »

Hi Overlag,

>i ment that the p47 was, mostly a bomber escort. Its job was to escort bombers, and protect them from fighters. Just getting them to break off was enough to forfill that plan.

That was what everyone thought before they tried it out. Just as the Germans in the Battle of Britain, the USAAF realized that it wouldn't work when they started the air battle for Germany.

Interceptors that operate under radar control over friendly territory have a big advantage when it comes to setting up intercepts. You can't defeat them by trying to get between them and the bombers - you can only defeat them by shooting them down in so large numbers that their losses can't be made good anymore.

To achieve air superiority, you have to destroy the enemy air force. Just pinging their planes is not enough, at least not in the long term.

Regards,

Henning (HoHun)

Stoney74 · « **Reply #113 on:** October 09, 2006, 12:33:45 AM »

Quote

Originally posted by HoHun
but the lighter cannon battery will leave you with more fuel for the hunt.

Only if you can find the 15 cubic feet required to put the fuel inside the airframe. There's no problem adding 684 pounds to the takeoff weight of the P-47. Its the space required. Changing the armament would not free up 15 cubic feet of wing area.

HoHun, where's the space inside the airframe to take advantage of your proposed weight savings?

Knegel · « **Reply #114 on:** October 09, 2006, 02:49:15 AM »

Hi,

with only 2 x 20mm the P47´s would have had the same problems like the Bf109F/G. It need much better shooting pilots to hit something.

Huhun always only count the firepower, while time to shoot and bullets per sec are also a very important factor, at least as long as the bullets are able to penetrate the target. This result in a higher hitprobability per armament and the lot of guns are also more reliable.

With the few percent of hits a normal WWII pilots was able to archive(i did read it was around 3 - 7%) a longer time to shoot to adjust the aim was a real advantage. Not many pilots was skilled like Graf, Hartmann, Moelders and Marsaille. The majority did shoot from much to long distance and wasnt able to calculate a good lead.
At the end of the war, with the new Gunsights, this problem got minimized much, but in 1943 and 44 many still effective guns imho was better vs Fighters than a few cannons.
The Brits did carry their .30cals not just for fun!! Same like the Germans they did use them to chase a enemy and to find a good lead to use the more effective but slow firing and low on ammo 20mm´s.

So if we assume a very good pilot, who got a hitquote per ammoload of maybe 30-50%, Huhun is right, while for the normal pilot the lot of guns, the more rounds persec per armament and the longer time to shoot probably was a advantage, at least vs smal nimble fighters.
Vs bombers iam all for cannons!

"Hohun wrote this

- The 8x 12.7 mm MGs did have about the firepower of 2 x 20 mm cannon.
- The 8x 12.7 mm MGs were about 684 lbs heavier than 2 x 20 mm cannon, with ammo and belting considered for both batteries."

But without ammo there is only a different of around 290lb.

And he also claim that 8 x .50cal have around the firepower of 2 x 20mm, thats true if we assume that always ALL bullets hit and that always ALL .50cal impacts are needed to down the fighter and if we dont care about the higher rate of fire of the .50cals.
If we see it per sec the 8 x .50cal shoot 104 rounds, while the HispanoII shoot only 20 rounds. Using Mr. Williams & Mr. Gustin´s guncalculation factors the 8 x .50cal have a more big firepower. The 2 x 20mm are closer to 6 x .50cal.
Accordinbg to Mr. Williams & Mr. Gustin´s the P47D had around 389kg(857lb) ammoload and a complete armament load(only guns and ammo, no belt etc) of 613kg(1350lb), so Huhun did assume a complete load for the 20mm´s of around 302kg(666lb inclusive 800 rounds).
According to Mr. Williams & Mr. Gustin´s thats a firepower of around 16000(this value is a calculation factor determinded by Mr. Williams & Mr. Gustin´s to compare the guns and their effectiveness) per amoload, while the P47D did carry a ammoload of 15640 destructive power.
Since 6 x .50cal was similar powerfull like the 2 x 20mm, they could have reduced the weight by deleting 2 x .50cal. So the weight already would have been down by 58kg(128lb).
And i never saw a cannon belt of 400rounds anyway. Was it possible to carry that many rounds in the P47 wing in ONE belt??

Edit: Made a typo and resulting a calculation misatke!

Greetings,

Knegel

gripen · « **Reply #115 on:** October 09, 2006, 04:27:07 AM »

Quote

Originally posted by HoHun

Talking about the US pilots who apparently were satisfied, I'm sure that's because they were never given the choice between eight heavy (indeed) machine guns, or two cannon and the weight of their mount 684 lbs down.

Hm... if the the P-47 had been designed for the cannons, it would have been 4 x 20mm not 2 x 20mm. Four cannons would have been a clear improvement.

Quote

Originally posted by HoHun

(It's also telling that 9th Air Force P-47 pilots refused the installation of rear warning radars, since they felt that 50 lbs of extra weight were too much. Now extrapolate that reaction to 684 lbs ... :-)

This has probably much more to do with air war situation when the tail warning radar was introduced; fighter units of the 9th AF rarely met German planes in air, so very little need for such device.

Besides, the tail warning was a standard equipment from the P-47D-40 onwards, including the P-47N which had longer range that the P-51D and weighed full loaded over 20000 lbs, some 2500 lbs more than full loaded the P-47D-25. So the weight of the weapons seem to have been quite minor factor.

Quote

Originally posted by HoHun

Well, re-configure the P-47 with 2x Hispano cannon and some internal tankage, and the Thunderbolt "does it over Schweinfurt".

Well, the P-47N did much more without change of the weapons.

Quote

Originally posted by HoHun

The title of this thread is "Improve the P-47", and I have not seen any suggestion that would have yielded a greater improvement than simply exchanging the US gun for a model the British were already using with great success.

Regarding the title of this thread, 4 x 20mm would had been an improvement while 2 x 20mm would had been downgrade according to US Navy rating ie one 20mm cannon equals three 12,7mm MGs.

Quote

Originally posted by HoHun

To achieve air superiority, you have to destroy the enemy air force. Just pinging their planes is not enough, at least not in the long term.

The P-51 did actually destroy the Luftwaffe with half or 3/4 firepower of the P-47. The P-51 units claimed more air to air kills in Europe than P-47 and P-38 units combined.

Notable thing is that statistically the only cannon armed fighter of the three primary USAF fighters did this destroying work worst and the weakest armed did it best.

gripen

Debonair · « **Reply #116 on:** October 09, 2006, 06:52:00 PM »

giving the wings about 2-3 degrees of washout, vortex generators, winglets, outboard LE slats; setting the 'pit back a couple feet more to increase critical Mach number; Q-tip prop & adding a spinner over the prop hub would do a lot more for Thunderbolt performance than the few percent weight reduction thats been discussed for the last 100 posts

HoHun · « **Reply #117 on:** October 09, 2006, 07:50:56 PM »

Hi Debonair,

>giving the wings about 2-3 degrees of washout, vortex generators, winglets, outboard LE slats; setting the 'pit back a couple feet more to increase critical Mach number; Q-tip prop & adding a spinner over the prop hub would do a lot more for Thunderbolt performance than the few percent weight reduction thats been discussed for the last 100 posts

Good list, but are you sure all of them would actually have helped, or were 1943 technology at least? Washout for example would tend to reduce the wing's efficiency, and if you mount outboard leading edge slats anyway, you might not actually need it.

With regard to the "few percent weight reduction" though, you don't seem to appreciate the impact it would have had on performance. Just look at this weight comparison:

P-47D-25RE: ca. 14500 - 14700 lbs
Cannon Jug: ca. 13816 - 14016 lbs
P-47M: 13275 lbs

OK, the Cannon Jug would not have been equivalent to a stripped-down racer, but it would have benefitted both in performance and manoeuvrability. (Just one example: At high altitude, the climb rate improvement would have been around 25%.)

If you still have the impression, that weight savings in the region of 5% are insignificant - we're talking about aviation here where 5% weight more or less is a big issue.

What do you think would happen in Aces High if the Cannon Jug loadout would be added to the list? 684 lbs saved, two Hispanos instead of eight Brownings ... which loadout would the players choose?

Regards,

Henning (HoHun)

Widewing · « **Reply #118 on:** October 09, 2006, 08:32:07 PM »

Quote

Originally posted by Knegel
Hi,

with only 2 x 20mm the P47´s would have had the same problems like the Bf109F/G. It need much better shooting pilots to hit something.

Greetings,

Knegel

Knegel make a very good point in that the odds of getting a hit on the enemy drop substantially if you have but two cannon.

Using Aces High as an example. HTC has stated that they researched the ballistic behavior of all guns modeled in the game. They believe it to be as accurate as the platform can allow. So, let's compare the relative bullet patterns by pitting a pair of Hispanos to the eight-gun brace of the P-47. The Hispanos are from a Spitfire Mk.XVI. Only the cannons were fired.

Both images were generated using the .target command, range set at 1,000 yards. The Spitfire is on top, the P-47 below it. Both fighters have convergence set at 350 yards. Guns were fired for 3 seconds for both types.

I don't think it takes more than a glance to determine which gun set-up is most likely to score hits. Likewise, the concentration of the Fifties is impressive. Note also that the Hispanos show a pronounced "drop" when compared to the Brownings. For the P-47, this simplifies obtaining hits by a considerable margin.

Personally, I believe the effectiveness of the Brownings is much greater than just two Hispanos.

My regards,

Widewing

gripen · « **Reply #119 on:** October 10, 2006, 03:08:27 AM »

Widewing,
Could you create similar presentation for the F4U-1C or the Typhoon because 4 x 20mm would have been practically only realistic alternative to the 8 x 12,7mm.

Thanks in advance.

gripen