Another 'Gem' from Greg - just released.

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Hi,
Interesting topics, "how early could so and so"? TBH, I suspect that many things happened dammed fast, but where some were actually slow off the mark, it seems to me that there were often reasons that could not have been avoided, in the real world.
With the P-51B, Be careful what you wish for! IMO, the big factor that got the Merlin P-51 versions into the top-spot was not just "The Merlin", it was really the fact that the re-engineering was done with the "Two-Stage Intercooled Merlin"! (OK, Aftercooled to some!)*.
As I read, there were serious thoughts about going for a Packard Merlin 28, or similar single-stage version, to speed things along for a British exported version. However, wisely, it was decided to hold-out for the full Two-stage engine, with the now-known superlative results! Possibly, if an early(er) change to a single stage Merlin had been produced for the Brits, maybe it would not shine so bright and might not have have been procured for the USAAF.

*Oh yes, really the two-stage Merlins do have some Intercooling.

Eng
 
If memory serves, under the damned fast category, Packard introduced some very significant production innovations. I believe that I read somewhere, or heard in a video, that the British produced Merlins had significant differences in tolerances on some key components. Packard (again, IIRC) introduced serial production of internal engine components that were very consistently manufactured to exact specifications, or more exact specifications. This contributed greatly to durability, reliability, and serviceability of the engines.
 
The P-38 had extended range due to extra internal fuel and drop tanks. The P51 had extended range due to extra internal fuel and drop tanks. The P-47 took until mid 1944 to get extra internal fuel and despite being the first US plane used from Europe as an escort in 1943 was the last to get drop tanks. If the lack of drop tanks was because of some homicidal "bomber mafia" then no US plane would have had them, ever. From the first US raid on Rouen which Hap Arnold witnessed on board a B-17, US planes were escorted by Spitfires as far as they were able, then they were escorted by Spitfires and P-47s as far as they were able. For the USA to request help from the RAF must have hurt their professional pride. The lack of drop tanks for the P-47 was indeed scandalous, but everyone else had them so who is responsible. Drop tanks are only part of the issue, adding 400 gallons of fuel in drop tanks to a P-47 or Spitfire allows it to to get to a place it cant fight for 20 minutes and get back from. It cannot be a surprise that US bomber forces were initially poorly equipped and trained for what they were doing, they hadnt done it before and no one else had. It is easy to say they should have trained and practiced forming up, what with, and when? Training accidents, forming up accidents and getting lost/landing accidents cost the lives of more crews than both raids on Schweinfurt, during the course of the war. To this end three emergency landing fields were constructed, until you are in English/ European weather conditions how do you train for them?
Greg blames some un named "bomber mafia" without putting any blame at the door of the people who designed and built the P-47, what did Republic think it would be used for? It panders to modern day conspiracy theories and theorists which gets Youtube "clicks", the true story is different, mundane misunderstandings, incompetence and foot dragging.
 
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Holding out for the 2-stage Packard Merlins meant that best part of 1943 elapsed without the Merlin Mustang to help out. Unfortunately, there was no mass modification effort of what was left of the Mustang Is into the Mustang Xs, nor there were mass-produced V-1650-1-powered Mustangs to be had in 1943.


Please see here, for example.
tl;dr of that is that Merlin was well suited for mass production much before Packard was involved.
 
This has been discussed many times here. It stems from an exchange between RR engineer Ernest Hives and someone from Ford (not Packard) when RR first started contemplating mass production and there were the first plans for a Merlin factory run by Ford in France. Hives had no experience of mass production, he was put where he was to learn about it. He had previously been involved in the racing sea planes, where the engines are hand made and fitted balanced to each other. By the time Packard started mass production Rolls Royce had their own custom built factories working to the same principles and tolerances, for the same reasons. It is a beautifully romantic vision, Derbyshire housewives filing pistons for their men to assemble into engines when the men get back from the pub, sadly not true though
 
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Hi,
This ship has sailed, old fruit.

Eng
 
The outlook for the European war (from USAAC/USAAF perspective) was bleak in 1940/1941, which is one reason the B-29 was conceived.
The outlook in early 1942 was a shift in planning, as Britain withstood the German onslaught. By late 1942, the U.S. started arriving in force and a steep learning curve commenced. Also keep in mind that Bomber Command had suffered serious losses trying to hit German targets, too - so this lesson was not a unique issue to the Americans.

No one foresaw the need for extra long range fighters at the start of the war. Fighters were intended for enemy bomber interception and had to be adapted to the new role.

People claiming that drop-tanks *should* have been a design feature from the start, are simply not looking at military doctrine through 1939 eyes, but rather from a long post-war perspective.
 
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Pretty much 100% pure male bovine excrement.
Unless somebody can come up the blueprints or a list/chart the details the difference between a Packard engine and a "British produced" of the same period in time.
I haven't seen one yet or heard of any actual differences, Like British connecting rods were built using dimension XX.X for this measurement and Packard used XX.Y.
We hear/read a lot of stories with no real details. Like exactly which parts. If a writer or commentator cannot say exactly which parts then he is just repeating rumors.
In NA in 1943 with the P-40F&L being the most common US Army fighter in the theater (the US used very few P-40K,Ms, Ns at this time) and they had not purchased enough spare engines or spare parts the British gave them hundreds of used Merlin engines to be used as source engines (parts) for overhauling the US Packard built engines.
Unless we believe that men in the overhaul shops in Egypt were hand filing the British parts to fit US engines?

There were several times that Packard introduced advanced features ahead of RR, like the the 2 piece block. However RR had already designed the 2 piece block and had sent the drawings to Packard. RR introduced the change on the MK 22 engine. They waited while they completed a number of MK XX engines with the old style. Little things like the winter Blitz and few other things going on in the middle of 1941. Packard was still tooling up and could build/order the manufacturing machinery to make the new parts instead of tooling up to make the old parts. Packard MK XX engines or the Packard equivalents were closer to MK 22s. Packard got the 2 piece blocks into production first, but Packard did not design the 2 piece heads or show RR how to do it.
Changing the cylinder blocks and heads requires changing the molds at the shops that do the castings at the foundries. Many of which are subcontractors. You also need enough molds to cast dozens of blocks and heads per day. You can't do a slow change over, it may not be instant but casting and shipping two piece blocks and single piece blocks or trying to assemble engines using both types of blocks in the same factory or assembley lines is not going to go well.

R-R Merlin. One/two piece cylinder block

I know that "the Merlin 61 was the first Merlin with two-piece cylinder blocks."(c) from British Piston Aero-Engines and Their Aircraft But i'm see to the Merlin XX and Merlin 66 cylinder block and not understand where is the second part? They look exactly the same. Merlin from Rolls Royce...
ww2aircraft.net
 
Between the wars there were ideas for "drop planes", massive planes with fighters that could detach and hook back up after seeing off the dastardly foe. Compared to that a self defending, bomber formation seems eminently sensible. Experiments were done into whether it would could work.
 
GrauGeist said:
No one foresaw the need for extra long range fighters at the start of the war. Fighters were intended for enemy bomber interception and had to be adapted to the new role.
Click to expand...
GrauGeist said:
People claiming that drop-tanks *should* have been a design feature from the start, are simply not looking at military doctrine through 1939 eyes, but rather from a long post-war perspective.
Click to expand...

Both Germans and Japanese were specifying long range fighters before the ww2 started. Both countries also have had drop tanks in service before ww2 started.
 
The only definitive thing I remember that came from Rolls Royce concerned the import of a machine from Switzerland via USA for machining of big end journals in the Manchester "Ford" factory. After it was installed Merlins came out like "shelling peas" with no issues about big end bearings in service. Shelling peas is an old English idiom for quick and easy to do. This says to me that RR concerns were about other issues than matching pistons. The first machine(s) was lost in the Atlantic, so a replacement ordered.
 
I sense a troll chumming the waters. I may be wrong - if Greg isn't your alter ego you have remarkably similar beliefs.

Couple of points AAC and AAF-hq prohibited external tanks pre-WWII (use Dec 7 for relevance). They were deemed a hazard to airmen' and pressurized tank and droppable tanks were strictly forbidden. February 20 1942 Arnold hosted the Fighter Conference in his office - focused dominantly on increasing range for fighter aicraft 'now that war in Pacific demands long ferry ranges'. The main agreement resulted in a Technical Instruction from Arnold to Tech Div at Wright Field - Increase Range of Pursuit, Dive Bomber, Light Bombardment Aircraft' dated March 2, 1942.

The Arnold instruction was preceded on 24 Feb, 1942 by DC/AS Gen Chidlaw to Chief, Tech.Div Mat.Cmd "Design leak proof Combat Tanks for all Fighter".

Lacking on ALL existing fighters were external pylons with release mechanisms and sway bars.

While Materiel Division sought input from Firestone, Goodyear, etc on the technical issues of designing a combat tank - the question of materials remained s well as Priority or critical material (i.e. steel, Jute, Paper, Alumi, etc, rack mechanisms to release in flight, etc. NAA and Lockheed and Curtiss and Bell developed wing and belly pylons for same detach as bombs. Not Republic.

While NAA installed wing racks on the first Mustang ordered by the Army, Lockheed designed centerline and wing racks, Bell and Curtiss designed centerline racks/sway bars and fuel feed lines.. Not Republic.

When the first steel combat tanks (52gal and 60 gal) were released - they were all immediately installable in late 1942/early 1943. Not Republic, which only rleased the B-7 bomb/fuel tank rack in summer 1943. The 205 gal paper, unpressurized ferry tank as delivered in March/May to ETO in 1943 had no provision to release from four attach points in flight - and deemed a 'hazard to flight safety'. The tanks were modified by VIII ATS, flight tested and released for combat ops - but the slave system from vacuum pump could only squeeze fuel up to 18-20K. Consequently ETO ops stated 80-100 gal only as th tanks must be droped before entering combat.

Greg can state without much argument that pre-war policies hindered pre Dec 1941 thinking with respect to external fuel tanks - but the need was immediately apparent for contemplated range extension or escort - and orders were given. Specifically after the Feb 1942 Fighter Conference and after the July 1942 Fighter Aircraft Range Extension Program.

Debtable is whether a more competent leader than Oliver Echols at Wright Field to drive a harder schedule to co-ordinate subcontractors in the design, testing and production orders for 75and 110 gal steel combat tanks.

Debateable is whether or not a more aggressive puruist of British suppliers at Botwater- Lloyd todesign and build pressurized 110 gal impregnated tanks locally.

Debatable is whether or not Kartveli could be suitably horsewhipped into action to develop first centerline fuel tank/sway bar for P-47B through D-6, or start design of a wing with pylons and fuel feed for delivery in 1942 like NAA and Lockheed, instead of Spring 1944 with P-47D-15,or design of increased internal fuel as stipulated by General's Muir Fairhild and Giles - but not delivering until (ETO ops) until May 1944 in units of 1-2 per squadron.

By contrast, the first flight of P-51B w/90gal ss prototype tank was mid July 1943 -Six months before the production drawing for the P-47D-25 370gal combined tank internal fuel was Released to production! Ditto P-38J with 2x55gal LE fuel tanks. Both the P-51B /85 fuse gal tanks and P-38 with 110gal wee flying combat ops in Dec/Jan 1944.

Summary - was Eaker over-optimistic that his 8th AF could win a war of attrition if given the inventory of 600 bombers materialized? Yes. Was Eaked VERY concerned that increased Fighter escort capability and quantity would be necessary for strikes into Germany? Yes, but in is memoirs he believed that a.) the B-17 gunnerswere taking a huge toll of LW, and b.) his attacks needed critical mass to break the outer ring of defense. Did Eaker and Asst Secy War Lovett pleaded with (and got) support from Arnold to divert P-38s and P-51s ASAP.

The issue is that at no time could Eaker tell Arnold - let's take a timeout, this is going to be too hard.

Not everyone, particularly Greg understood what a setback (and blow) to Eaker 8th AF plans caused by Eisenhower's insistence that the P-38 FGs gaining experience in 8th AF - be extracted and sent to Torch - completely emasculating VIII FC until start of P-47C combat ops in April 1943.

IMO Greg never has truly grasped the importance of remaining internal fuel, after dropping tanks to enter combat, fight for 20min, cruise back and have the 45gal for loiter on return. The initial Combat Radius charts as originally published were not only straight line clear weather flight to a point, fight and return but failed to account for group warm up, take off, assemble switch to external tank cruise to altitude to R/V but then account for escort flight speed (or increase flight length due to essing at 220 IAS when the bombers are at 150IAS at 25,000 feet.

No accounting for re-routing around thunderstorms or 90kt headwinds that complicate real world planning for 8th AF.

BTW - if this is you Greg, now is time to drop kimono and come out of the closet? These gentlemen would like to know.
 
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The US seems to have done a back and forth on drop tanks, a real to and fro shuffle.
This is just by observation and no written proof.
Drop tanks or at least detachable tanks (not quick release?) were used on several single engine US aircraft in the 1930s and on more than one export plane.
The US was vast and just moving planes around by air was not easy. The planes may have been rated at one gross weight for combat and at higher gross weight with a detachable tank for ferrying.
The P-35 and P-36 held a lot fuel if they were filled up, I don't know what the limits on the P-35 were. On the P-36 the fuel tanks would hold 160 US gallons but the took you over the designed gross weight, it may also have put the aircraft in a marginal or dangerous CG situation. The design gross weight and the performance numbers were for 105 US gallons. The extra fuel was in the behind the pilots seat tank.
With the P-40 the tanks stayed the same (mostly) but design fuel went to 120 US gallons. Some sources say the P-40 held 180 gallons but this may be a misprint from 160 gallons.
The P-39 prototype's had large fuel supply, some sources say 200 US gallons, by the time they get to the YP-39 and P-39C they have 170 US gallons.
The P-38s started with 400/410 US gallons internal.

Now none of these were enough to escort a B-17 (or even a B-18) but aside from the Japanese, these were well in excess of anybody else's single seat fighter fuel capacities.
Except........................................
This were for unprotected tanks. Once the requirement for protected tanks shows up Bell, Curtiss and Lockheed start jumping through hoops.
P-39D fuel capacity drops to 120 US gallons,
P-40B fuel capacity drops to 135 US gallons
P-38D fuel capacity drops to 300 US gallons.
Forget escorting bombers, US fighters need more fuel just to move from airbase to airbase inside the US.
The P-39D was given a 75 gal drop tank, later larger for ferry use.
The P-40C was given around 145-148 gal internal (new self sealing) and a 52 gal under the fuselage.
P-38s were given a pair of 75 gal tanks, at least to start.
Now at this time (end of 1941) the 2nd P-47 is rolled out the door, it needs rework. Yes the R-2800 is a fuel hog, But the P-47B is also a flying tanker, at least by Dec 1941 standards. It has 305 US gallons of internal fuel in protected tanks. The P-47 can't escort US army bombers but the P-47 without drop tanks can out range most of the US fighters (P-38 excepted) with their small fuel tanks. It takes until March of 1942 for 6 P-47s to exist. The US is pumping out drop tanks left and right, but they are for the old fighters with the small tanks.
IN the Spring/Summer of 1942 the priorities may have been just getting enough fighters of any sort. It took until Aug 1942 for P-47 production to exceed Mustang production (change over to A-36 production helped a lot).
They hung bigger drop tanks on the P-39 and P-40 for ferrying but they were useless for combat. Anything much over 75 gallons means they could get deeper into enemy territory than they could get out.
You also needed more power (or bigger runways) than the 1941 fighters to carry bigger tanks. P-47 has a problem. You can get a P-40E carrying a 500lb bomb off of dirt in 2/3s the distance you can get a clean P-47C off of concrete.
P-38s were always one step ahead of the P-39 and P-40. The turbos allowed them to use lower supercharger gears than the P-39/P-40 for around 100hp per engine until you get to the J/L. Then things really changed.
Now at what point somebody should have leaned on Republic for different/ better drop tank set up I don't know and I am not going to question Drgondog on any of the 1942, 1943 memos and orders/letters.
It just looks to me (without written sources) that Bell, Curtiss and Lockheed were trying to restore original pre self-sealing fuel capacity/range/radius/endurance and not extend it in 1941/early 1942. Lockheed may have gotten lucky? once they had the plumbing for the 75 gallon tanks fitting the 165s (?) was no problem and the P-38s could lift the bigger tanks without runway problems.
 
Rarely mentioned in these discussions is that the USA was at war. The President of the United States of America along with the Prime Minister of the UK and their combined chiefs of staff had took part in the Casablanca conference in Jan 1943 and the Pointblank Directive of 14 June 1943 concerning the combined bomber offensive. There was massive pressure to "do something" however unwise that was, talk of range and drop tanks didnt impress uncle Joe who was losing people by the million.
 
I am definitely not a troll. I'm exactly what I stated I was. I am a more casual observer than many on this forum and far from an expert. I have far more interest than John Q. Public though, and have read books occasionally and visited aviation museums my whole life. Also done some on line reading. Some of Greg's arguments make sense to me. The sheer amount of anger and vituperation that I see on this forum is alarming. I'm not sure why anyone would be so triggered by differing viewpoints about something that happened 70 years ago, and which have at least an element of truth to them.

We've been lied to so many times by our government (and by corporate America) that I have a healthy degree of skepticism towards those in positions of authority. For example, "dropping a bomb in a pickle barrel from 20,000 feet," when in reality, what was the statistic? Fewer than 5% of the bombs fell within one MILE of the target or something like that? They KNEW they were lying about the pickle barrel. What else did they lie about? Yet, I'm not a moon hoax person. Buzz and Neil really went there.

Someone upthread reported, and I haven't verified, that the Germans and Japanese had operable fighter drop tanks in 1940. We didn't. That's really the bottom line in this debate to me. The memo is damning. We were caught trying to catch up after having already entered the war. Many people died, others got promoted.

I'm glad to see your last two paragraphs above, though I doubt a lot of thunderstorms were deviated around in western Europe. More likely, in my non-expert opinion, were deviations around known flak batteries. But it would seem that the charts ranges have to be modified to allow for operational realities, that's true. And I stick by my assertion earlier that it appears USAAF did not have the proper operational policies and procedures (and discipline) in effect to make maximum use of their resources. Yet, they told the public in what amounts to little more than propaganda that strategic bombing could win the war, another lie.
 
PlanesandShips said:
Someone upthread reported, and I haven't verified, that the Germans and Japanese had operable fighter drop tanks in 1940. We didn't
Click to expand...







There are more.
Some may have been detachable instead of dropped inflight, at least one supposed to dropped in flight in case of emergency (fire?).
one more.

because of the landing gear it is often hard to tell if they were carrying a bomb or tank, no fins on this one.
 
There is no inherent disagreement, just Greg being evasive because it blows his "bomber mafia" theory out of the water the P-47 did not have the internal fuel to perform deep penetration escort. A drop tank increased the range slightly but it was a thirsty beast. Th idea of self defending bombers was not based on a single guy with a single gun defending the plane. It was based on a formation meaning any enemy attacking a formation of say 300 bombers would face hundreds of guns from any and all directions. The theory we now know to be wrong in part but at the time it wasnt. When the British said it didnt work the counter argument was that the British werent using enough to provide the mutual defence. Later when the USAAF started, some raids went well it "proved" the theory worked but these were not deep penetration raids into Germany so were not heavily defended and defending gunners massively overclaimed because the number of claims is proportional to the number firing guns. I posted that the theory was wrong in part because USAAF formations did inflict losses, around 10% as I remember on the Schweinfurt raids mainly twin engined types. I repeat the P-51 had external tanks and increased internal fuel from just after when it was first produced, kits were sent to be installed on the first production models that had already been shipped. The P-38 wasnt originally tasked with bomber escort from UK, when it was increased internal fuel was added for late 1943. The P-47 which had started arriving in Nov 1942 and became operational in April 1943 didnt get increased internal fuel until mid 1944.
 
tomo pauk said:
Both Germans and Japanese were specifying long range fighters before the ww2 started. Both countries also have had drop tanks in service before ww2 started.
Click to expand...

And Curtiss had drop tanks for the Hawk 75 which in US service was the P-36.

As we know from the post 54 Curtiss were working on the drop tanks in May 39 and it would appear Curtiss hoped the USAAC would pay for the design. I am guessing some foreign customer had requested drop tanks as an option but I do not know who or if they actually sold any to foreign customers.
 
Ok, you proved me wrong.

However, I was clearly speaking of the P47 in 1942 and 43, the critical time for the only plane capable of performing escort duties in Europe for all the reasons listed by others above. The one plane that might have mitigated the horrific losses.

I'll admit that I didn't know all those previous generations of lower performance airplanes had drop tanks. But now you've piqued my interest.....if drop tanks were "normal," why the memo doing away with them? Perhaps because the brass thought self protecting bombers didn't need them?
 
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