P-47: Range, Deceit and Treachery

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Reluctant Poster said:
The attached document (an appendix of the Air War Plans Division AWPD-1) gives the USAAC perspective on deployments in the event of the seemingly inevitable war with Germany.

The following excerpts are interesting:


View attachment 586437


View attachment 586438

View attachment 586439

The primary purpose of the the pursuits to be based in GB was to protect the USAAC bases but as it tuned out this was not necessary so the role in actuality became short range bomber support, but the important thing to note was that the idea of long range escort was still given at least some support.
Click to expand...


This was the period in which Plans and Materiel Command were striving for solutions for long-range escort - without any notion that a single engine fighter would/could achieve the range requirements and all development thinking was dedicated to multi engine escorts. The P-61 and YB-40 emerged and, ultimately the worst of all, the XP-75 as the single engine nightmare designed around firepower and range.
 
Yes, it seems they were more focused on something like the Seversky idea of a "convoy fighter" that would fly along with the bombers and essentially trade broadsides with the intercepting fighters. Probably the ultimate expression of that idea was the Lockheed XP-58, with two V-3420 engines and two remotely operated turrets.

That was the same era which produce the YFM Airacuda and BP Defiant, both of which were supposed to stand off and blaze away at enemy bomber formations. If you are being opposed by Airacudas or Defiants I suppose something like the XP-58 or XP-75 actually would have worked for escort.

And the Convoy Fighter was supposed to fire "aerial torpedoes" at enemy aircraft, kind of like an F6D Missileer was envisioned to do, and later a CAP version of the Grumman A-6.
 
By the way, getting back to range for a fighter. Look at the numbers for the BF-110C-4:

Range: 481 miles at 262 mph at sea level, 528 miles at 304 mph at 16,400 ft, 565 miles at 301 mph at 22,970 ft.

So that "long range escort fighter" had about the same range as a Spitfire Mk1, a bit less than a P-39 without a drop tank, and significantly less than any P-40 even without a drop tank. It was Long Range only in comparison to the BF-109.
 
MIflyer said:
Range: 481 miles at 262 mph at sea level, 528 miles at 304 mph at 16,400 ft, 565 miles at 301 mph at 22,970 ft.

So that "long range escort fighter" had about the same range as a Spitfire Mk1, a bit less than a P-39 without a drop tank, and significantly less than any P-40 even without a drop tank. It was Long Range only in comparison to the BF-109.
Click to expand...

See; http://zenoswarbirdvideos.com/Images/P-40/P-40FOIC.pdf
range for a P-40E with 120 gallons of internal fuel was about 425 miles at just about the same speeds quoted for the Bf 110. even if the P-40 started at about 15,000ft with 148 gal of internal fuel it would be good for about 525 miles at just over 300mph. The 110 was not significantly shorter ranged than the American aircraft.
A P-39 magically levitated to 15,000ft with a warmed up engine and 120 gallons of internal fuel was good for a bit over 500 miles at 312mph .
 
The B-26, like the B-25, was a Medium bomber. And that meant a medium sized airplane carrying a medium sized bomb load over medium distances at medium altitudes.

Did y'all know that the T-29 originally was tried out for the AC-47 role?
 
MIflyer said:
By the way, getting back to range for a fighter. Look at the numbers for the BF-110C-4:

Range: 481 miles at 262 mph at sea level, 528 miles at 304 mph at 16,400 ft, 565 miles at 301 mph at 22,970 ft.
Click to expand...
That's a pretty good range considering the speeds: Was this with drop-tanks or without? It seems the performance was such that had they simply used waves of fighters to surge ahead of the bombers



See 7:30 to 10:00
 
I`ve been doing a little "accidental" research on this as I`m trawling some USAAF historical review documents. Which I saw was also posted
by RCAFson

Skipping away from the actual story about drop tank development, there is one interesting operational detail which seems to need
some clearing up.

I`m a bit confused as Greg states that in the 1st Schweinfurt Raid, the escorting P-47`s didnt have droptanks (well he says they DID, but then
put an on-screen not saying "didnt"). This is backed up by Wikipeadia which also says the P-47`s on the 1st Schweinfurt raid did NOT have
droptanks, which in turn claims this fact from "How to Lose WWII: Bad Mistakes of the Good War" - by Bill Fawcett. I dont
own a copy so cannot see where HE got it from.

However.... the USAAF historical review (pg 98 & 99 in original page #`s) says the opposite... BUT interestingly appears to suggest the effect
was perhaps similar as the droptanks were "Partially-filled."

1594425468449.png


I`m not sure if perhaps this goes a small way to explaining some of this ?

I really dont know the "droptanks" story particuarly well, I just stumbled on this and thought it might
have some relevance.

I note at 15:00 into Gregs video he shows that the P-47`s COULD have made it to Schweinfurt with the 200 gallon drop tanks
but "were not equipped with it due to beaurcratic reasons and NOT any limitation of the plane itself."

Annoyingly the USAAF review does not state WHY the 200 gallon tanks were only "partially filled". So someone will have to
do more digging on that one. I dont know if that was some instability issue, or the tanks not working properly (pumps etc).

Or is this USAAF review wrong, and the P-47`s on that mission DIDNT have the tanks at all ? As per wiki & Greg.

The documents seems to suggest "Reference #144" which is a document I do not possess, but if someone has it,
it might be very enlightening:

1594427471477.png
 
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Snowygrouch said:
Annoyingly the USAAF review does not state WHY the 200 gallon tanks were only "partially filled". So someone will have to do more digging on that one. I dont know if that was some instability issue, or the tanks not working properly (pumps
Click to expand...
Is it possible there just wasn't enough of the right grade of fuel in the right place at the right time? Logistics wins wars.
 
I believe this has been gone over before. The 200 gallon tank was a ferry tank and was not built to be pressurized. It had problems feeding the fuel to the airplane at altitudes of around 20,000ft or higher (?). Not a problem on a ferry flight but it was a problem for combat/escort. But a 1/2 full ferry tank could allow the P-47 to take-off (on the main tank) switch to the ferry tank, form up with it's squadron, climb to the high teens or 20,000ft and get part way across the channel. Any overflow fuel is being routed back to the main tank. Planes are in formation, part way (or all the way ?) across the channel and near the desired altitude when the tanks are dropped. A P-47 could suck up 105-135 gallons warming up, taking off and climbing to 25,000ft according to charts in the manuals. add in the fuel needed to form up the squadron or entire fighter group and the "boost" in range even a 1/2 full ferry tank could give was considerable.
Having engines cut out due to unreliable fuel feed was not something they wanted to deal with.
 
The problem in July-August 1943 was two fold for the P47C/D in theatre. First VIII ATS had just developed the kits to slave tank pressurization for external tanks ia instrumentation vacuum pump, and second the 200 gallon was strictly a unsealed stainless steel ferry tank. In addition the 200 gallon tank was a.) dangerous to the empennage when released and b. very draggy. SS 75 gal combat tanks began arriving in numbers in August, but not enough for all escort fighters to be equipped with them. The 108-110 gal SS combat tank began arriving in September, followed by the flat 150 gal tank - all for centerline mount - in November-December. I have to dig up when the first Brit made impregnated paper combat tanks began service.
 
QUOTE="Snowygrouch, post: 1568154, member: 68059"]I`ve been doing a little "accidental" research on this as I`m trawling some USAAF historical review documents. Which I saw was also posted
by RCAFson

Skipping away from the actual story about drop tank development, there is one interesting operational detail which seems to need
some clearing up.

I`m a bit confused as Greg states that in the 1st Schweinfurt Raid, the escorting P-47`s didnt have droptanks (well he says they DID, but then
put an on-screen not saying "didnt"). This is backed up by Wikipeadia which also says the P-47`s on the 1st Schweinfurt raid did NOT have
droptanks, which in turn claims this fact from "How to Lose WWII: Bad Mistakes of the Good War" - by Bill Fawcett. I dont
own a copy so cannot see where HE got it from.

The first 'belly tank' mission was flown by the 4th FG on July 28 at the tail end of Blitz week. The 200 gal ferry tank was partially filled at the recommendation of Cass Hough. The reason for filling only~150 gallons is that with lack of internal pressurization to suck fuel from the tank at approx 18000 feet, the fuel and the tank was only useful for climb and crossing Channel until ~18K - then drop. At first Monk Hunter forbade dropping the tanks but all Gp CO's raised the single digit salute and told their pilots to exercise best judgment.

The tanks were used by the Penetration and Withdrawal efforts for the August 17 strike. One week later the 4th and 56th and 353rd FG began the conversion to install the B-7 C/L rack capable of attaching the new 75 gal (and 108 gal) combat tanks coming from US. By late September the 108 gal tank was operational at all six 8th AF FGs (4, 56, 78, 352, 353 ans 355). Sources: 4th and 56th FG squadron/group histories at USAFHRC.

However.... the USAAF historical review (pg 98 & 99 in original page #`s) says the opposite... BUT interestingly appears to suggest the effect
was perhaps similar as the droptanks were "Partially-filled."

View attachment 587718

I`m not sure if perhaps this goes a small way to explaining some of this ?

The USAAF history is correct.

I note at 15:00 into Gregs video he shows that the P-47`s COULD have made it to Schweinfurt with the 200 gallon drop tanks
but "were not equipped with it due to beaurcratic reasons and NOT any limitation of the plane itself."

Politely - Bovine Fecal Matter. 'Greg is clueless regarding the feverish activity by Col Cass Hough to modify the P-47Cs with the centerline keel and B-7 racks as well as developing the external tank pressurization slaved off the vacuum pump - IN ADVANCE of Republic. The only factoid which smacked of 'bureaucracy in the ETO was Eaker inexplicably dragging his feet to authorize the 108 gal impregnated paper tanks made in UK. That said, the first use was the 56th FG in first week of September - AFTER the B-7 rack conversion - three weeks after Schweinfurt/Regensburg strike.

Annoyingly the USAAF review does not state WHY the 200 gallon tanks were only "partially filled". So someone will have to
do more digging on that one. I dont know if that was some instability issue, or the tanks not working properly (pumps etc).

As above. Unless you change 8th AF operational escort tactics and cruise at 15-17K until 200 gallons are expended (not a good idea in summer 1943), then the amount of fuel in the 200 gallon tank which remained when following SOP to climb to ~ 22-25K, was 50-75 gallons of useless weight, drag and a combat fire hazard was underneath every escort fighter..

Or is this USAAF review wrong, and the P-47`s on that mission DIDNT have the tanks at all ? As per wiki & Greg.

Your instincts in seeking 'in period' docs in ETO are entirely correct when parsing Wikipedia for well sourced data

The documents seems to suggest "Reference #144" which is a document I do not possess, but if someone has it,
it might be very enlightening.

Recommend also seeking facts in well done USAF Study 136 - Development of the Long Range Escort Fighter' by Boylon. You can download if you don't have.



The keys to delivering the greatest possible escort combat radius for the P-47C/D in the ETO were:
Centerline Keel and B-7 Rack
Creation of Pressurization kits for all P-47D delivered prior to D-11
Development (at Republic) of special run of D-6 with internal plumbing and provision for wing racks - which unfortunately was a very lengthy depot modification to convert all P-47D prior to factory equipped D-15/-16. Prior to conversion all the earlier P-47C/D models, only the 75. 108 and 150 gal tanks could be mounted - B-7 rack only.
Deliveries of D-16 through D-23
Delivery of initial D-25 mid May with 370 gal internal fuel plus wing rack plus internal wing plumbing plus factory external tank pressurization slaved from engine/vacuum pump.

By contrast - the P-51B-1 arrived in September 1943, operational December 1943 with external racks for fuel tanks and bombs, with pressurization kits to feed to 30K+, and 85 gal fuselage fuel tank kits beginning in November 1943. The first 85 gal kits were installed in late November. When that ship was on the flight line in December (not all as the conversions continued through Feb-March 1943), the P-51B-1 with two 75 gal tanks had more combat radius (through mid Poland) had more fighter escort range than the first P-47D-25s six months later.
 
According to Warren Bodie in his book "Thunderbolt" the 4FG had been equipped with the huge 205 gallon tanks for a mission on 28 Jul 1943 and again on 30 July 1943. They were very unimpressed with the results. The 56 FG were equipped with the 205 gallon tanks for the first time for the mission on 12 Aug 1943. Reportedly the tanks did not always separate properly. So they quit using them and on 12 Aug flew their first mission with 75 gal pressurized centerline drop tanks, which actually gave them 20 to 40 min more flight time than the "205 gallon monstrosities."

The book also says that Gen Kenny in the Pacific got tired of waiting for suitable drop tanks and had his people develop the 200 gallon "Brisbane" tank which was then produced by Ford (in the US or Aus?)

Also, as far as the long range cruise techniques developed by Lindberg in the Pacific, that relied on flying with maximum boost at very low altitudes, as in a few feet above sea level. That was possible in the Pacific, where there were long stretches of open water to be transversed and where there was virtually no chance of being shot at. That situation did not occur in the ETO until after the Germans had been kicked out of France and our fighters were based in France. Since they usually needed to carry bombs and not drop tanks they did use those cruise techniques for crossing non-hostile territory (reference the book on the Hell Hawks P-47 group). .
 
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