Greg of Auto and Airplanes has asked for a Debate

Ad: This forum contains affiliate links to products on Amazon and eBay. More information in Terms and rules

RaptorFan said:
He can be very curt. Supposedly is like that in his auto business. Btw, I'm the one who replied to your YouTube comment. I wasn't sure if you meant Greg or Bill since many of the comments were how Bill was outmatched.
Click to expand...

My words were about Greg's approach. drgondog didn't engage in ad-homs or begging the question. I don't know the technical stuff about P-47 range beyond generalities, but I damned sure know my way around debate.

Bill could've laid or made points better, but with a couple of exceptions he was very on-point, whereas Greg repeatedly cited the "Bomber Mafia" in a debate where he was trying to show the "Bomber Mafia" turned the scales, or even existed with the power to determine not only doctrine but equipment. He also pushed goalposts by saying the "Bomber Mafia" was only about 8th AF, wobbling around about 5th AF, and totally discounting 15th AF experiences.

Bill was of course hampered by technical issues, at which (snicker) a conspiracist might raise his his eyebrows. I think he did fine, though not enough to get Greg's crowd to stop and think.
 

Greg's crowd won't stop and think either way. Its like a cult. lol
 
Hi,
I think we agree on most of this but, you make some points that I think need clarification to keep us on target!
Aircraft fuel systems vary hugely in detail, but there are many basic limitations that apply and general standards, but where we talk specifics we can be more well defined.
My first point about modern airliner tanks generally not being pressurised was to counter Greg's strange point about modern airliner tanks not needing to be pressurised above 20,000 feet. Well, as we know, this is true for the modern state of the art. However, it is just his smoke and mirrors because there are huge problems with vapour pressure and fuel delivery that require technical solutions for all applications and I think he just said this to cloud the issue and that was my point.
The main point about external Drop tanks is that they are/were pressurised to transfer fuel by air pressure, pushing the fuel up into the aircraft fuel system. Trying to draw fuel by a remote "suction" is doomed to fail esp with low vapour pressure fuel.
So now we get onto WW2 fighters. Yes, of course most used "suction pumps", most pumps have a suction side, booster pumps certainly do, even immersed booster pumps and they have to be designed to avoid vapour lock or cavitation with their specific application, they are no pure panacea for the physics of vapour pressure/cavitation, they have to be designed to match the application. However, we are rapidly getting on to detail. In WW2 there was usually an engine mounted mechanical fuel pump that drew fuel from the aircraft supply. This supply was usually gravity fed with the aircraft upright. Is this the "pump" you mean "between the tanks and the engine" and "share a single pump between all tanks"? Certainly, many early WW2 fighters did have the legacy gravity feed (like the early Spitfire), but generally an electric booster pump later became a feature that was often immersed in the feed tank as in the Bf 109. Sometimes several tanks had immersed "booster pumps" like the P51D and P47, Fw 190, later Spitfire and most where there were several tanks. Sometimes these other tank pumps were transfer pumps that fed the main or feed tank, sometimes they could feed directly by selection.
A common point though, is that these WW2 systems often didn't use the Booster pump continuously, and when the Booster pump was off, the engine drew fuel at suction with gravity, which obviously has greater risk of vapour lock, esp with increasing fuel temp and altitude, not to mention manoeuvre.


Eng
 
For all the talk about the "Bomber Maffia" believing in the self-defeding bomber concept, most, if not all, Eighth Air Force bombing raids were flown with some sort of escort.

The escorts may not have been able to support the bombers all the way to the target on many missions, but they still provided valuable support.

I think Greg described the YB-40 as a heavily armed "self-defending bomber", but it really was an attempt an an escort plane.

Also, regarding the combat in New Guiniea that was over 300 miles there and another 300 miles back, with 1 hour combat, Greg himself adnmits that the return journey would have to be "careful" - which I take to mean flying the plane for maximum ange - that is, quite slow.

And I think he missed the point that drgondog was making - that 1 hour of combat would have drained so much fuel that there wouldn't be much left for teh return flight. Unless he is saying it was all done with the 200USG tank attached.

Also, the highest point in teh Owen Stanley Range is ~13,250ft, so it would be possible to make the flight at, or lower than, 20,000ft.
 
Thumpalumpacus said:
He also pushed goalposts by saying the "Bomber Mafia" was only about 8th AF, wobbling around about 5th AF, and totally discounting 15th AF experiences.
Click to expand...
General Kenney so hated by the Bomber Mafia he became the first head of SAC. Yes the bomber mafia was all powerful unless you were in the SW Pacific.
A lot of Greg's argument originates with Trent Telenko & his conspiracy theories. I linked to it above.
 
The devious anti escort anti drop tank bomber mafia sent the P38s to the Med where they....escorted bombers? Lol

Also one does wonder how it is that Republic alone among aviation companies could not produce a pressurized drop tank.

Greg claims that they developed the G10 and K1 pumps because they were blocked from proper tank development? I know others here are already discussing the flaws in Greg's pump logic but I would be curious to know more about the G10 and K1 pumps he believes were magical cure alls for lack of pressurized tanks. I imagine like most things he is either omitted details or spewing utter nonsense. Seems to me that if every airplane could have solved its fuel pressure problems with wonder pumps they would have been everywhere and in everything.

But we're not the 75 gallon tanks used by various escort made for the P39 originally or something? Curious how both Bell and Lockheed seemed capable of making decent drop tanks but Republic could not.
 
I know he's asked for debate. I've paid for an argument but apparently this is only contradiction.
 
Engineman said:
Is this the "pump" you mean "between the tanks and the engine" and "share a single pump between all tanks"?

Eng
Click to expand...

No. The engine driven pump is the last pump in the system.

Immersed pumps were first used in the USAAF on the P-47 and later P-51's. From memory the P-47 only had one immersed pump per wing and definitely also had another electric pump preceding the engine driven pump. Late model P-38s had immersed pumps in the outboard tanks only.

Greg seems to forget about all these pumps and states that pressurizing fuel tanks is not necessary. As will be seen below it is necessary on all aircraft operating above about 12-15,000 ft.

Here are the electric boost pump positions of a variety of aircraft, including P-47 seeing that it Greg's fetish. You will note that both the P-51 and P-47 have pressurised drop tanks, which Greg says is not necessary. Early P-38 aircraft did not have pressurised drop tanks but later ones almost certainly did have.

P-38 - item R - one per engine in the centre nacelle on early aircraft and additional ones in the pylons on later aircraft. Used continuously above 12,000ft to prevent vapour lock. Early drop tanks are vented to atmosphere and depend on the electric and engine pumps to suck fuel out of them. One of many reasons to use the fuel in the drops as soon as practical (usually after 15 min flight).



P-39. Item C mounted each wing. Drop tank not pressurised.


P-40. Item 21 mounted on the front of the wing on all models starting with the D. The earlier models had a wobble pump fitted. Drop tank not pressurised.


P-47. Item 8. Not shown are the two internal wing tank pumps. On early aircraft when those failed all the remaining wing fuel became ballast. On later aircraft this was fixed by re routing the fuel lines so that the electric pump would gravity feed. The drop tanks were pressurised but still prone to vapour lock which required dropping below 10,000ft to allow mother nature to fix the problem. Something Greg likes to ignore.



P-51 Allison installation. Item 9


P-51 Merlin installation. One electric pump per internal tank. The drop tanks are pressurised to force the fuel from the tanks up to the engine driven pump.


 
Last edited:
I have looked through my manuals and microfilm and can find nothing to confirm or positively reject the idea that later P-38 fuel tanks were pressurised

From the microfilm blueprints 300 gal tank P/N 194645 is definitely not pressurised and is shown as fitted to F and G model aircraft. It is not listed in this parts catalogue. The only two tanks listed are both 150 gal. One is Lockheed P/N 195318 for which I do not have a drawing and the other is a wooden vendor tank.


Checking TO 00-25-4 -- that shows both the 150 gallon (165 gallon) and 300 gallon (310 gallon) tanks used on the P-38 were the same as the tanks used on both the P-47 and the P-61 which means that it was designed as a pressurised tank.



This does not guarantee the tank was used pressurised on later P-38s but the pylon drawing 194131 shows two pipe lines leading to the tank so that would suggest, but again is not proof, they were pressurised. I have marked one pipe line in blue and one in red. Some will note a third tube further forward ending at the bomb shackle. That is a wiring conduit.


Finally I note for those who still believe Greg that pressurisation was not needed. The late model T-6 aircraft had drop tanks and those drop tanks were pressurised. See the section of NAA drawing 168-48401 where is shows
 
Actually the Combat Box formation, as defined by creating formation flight assembly to a.) concentrate bombers into a small (er) volume of space to concentrate bomb pattern, b.) create interlocking fields of fire for gunners, c.) 'Stagger' the formations to ensure best possible safetyfrom aircraft in box formation fro other bombers at different altitudes - properly belongs to LeMay.

Ditto the concept of 'best of the best' lead crew navigators and bombardiers assigned responsibility to guide formations to Initial Point, guide to the target and bomb specific target - with rest of squadron releasing bombs.

The lack of imagination that a long range s/e escort fighter with enough fuel to a.) escort to target, b.) fight high performance s/e interceptors bf 109 and Spitfire, and c.) return safely Was a real factor - and a belief held by All combatants save perhaps the Japanese which fielded the A6M with (unpressurized) drop tanks and extremely low wing loading. That said, the Japanese had no high altitude strategic bombing doctrine held solely by US.

AFAIK, only Lockheed and NAA focused, early, on dual use wing rack capability (in US), in their fighter design offerings- with Lockheed leading the actual production delivery.
 

Lots of fuel systems.

MiTasol. "Immersed pumps were first used in the USAAF on the P-47 and later P-51's. From memory the P-47 only had one immersed pump per wing and definitely also had another electric pump preceding the engine driven pump."
My interpretation from these and other illustrations of two of the important aircraft fuel systems in this discussion, the P-51 (Merlin) and the P-47D, is that they had immersed pumps in the main feed tank (tanks for the P-51 (Merlin) ) that can feed fuel under pressure to the selector valve with the immersed pump ON. Also, the fuel from the drop tanks is fed by air pressure to the selector valve. Neither of these types seem to have another external booster pump after the immersed pump.

So we still have a problem with the term "pressurising fuel tanks". There are no aircraft in all your illustrations that have pressurised aircraft internal fuel tanks. The only pressurised tanks here are, the P-51 (Merlin) and the P-47D DROP-TANKS as you note, that use air pressure to force fuel to the selector valves and then directly into the engine feed line to the engine driven pump. So, I believe the term "pressurising fuel tanks" has been misused by some for the need to operate the "booster pump" or "electric auxiliary pump" in some circumstances to avoid vapour lock.
Note that, ALL the Allison fuel systems you show do have external "Electric Auxiliary Pump (s)" that draw fuel from the tanks and, as you have said, may be more prone than well designed immersed pumps to vapour lock.

MiTasol. "You will note that both the P-51 and P-47 have pressurised drop tanks, which Greg says is not necessary. Early P-38 aircraft did not have pressurised drop tanks but later ones almost certainly did have".
I agree, the P-38F appears to have unpressurised drop-tanks that rely on vent pressure to supply the engine driven pump when the electric auxiliary pumps are turned OFF, and even with the electric auxiliary pumps ON, that feed will be vapour-lock prone.
In fact all the Allison powered aircraft here appear weak in this aspect, as you note, the P-38 requiring the electric auxiliary pumps on for flight above 12,000 feet, etc.

The other Allison powered aircraft have similar problems, in fact, the P-39 as shown is worse, the unpressurised drop tank feed having no other pump in its feed until the EDP.

Eng
 
He is generally credited with the finished product, and certainly refined it during the war. But the concept of self-defending bombers with interlocking fields of fire was hardly new. In fact, that was one of the leading pre-war theories on how to protect deep raids. From USAF Historical Study no. 136: DEVELOPMENT OF THE LONG-RANGE ESCORT FIGHTER:

Almost all of the sources discussing the issue in the interwar years recognized the need for escorts. But in part because they weren't feasible, many proponents decided they weren't essential: (THE NEGLECT OF LONG–RANGE ESCORT DEVELOPMENT DURING THE INTERWAR YEARS (1918–1943) https://apps.dtic.mil/sti/tr/pdf/ADA393237.pdf )

Moreover, even early war experiences didn't fully deter proponents from the view. Again from Historical Study 136:

It is impossible to quantify how much if any impact this had on the decisions to provide combat drop tanks to escorts early in the war. But it does seem the priority could've been higher, despite all the competing demands.
 
Thumpalumpacus said:
I'm not a fan of how he talks to his viewers. I do watch his vids and try to glom some stuff.
Click to expand...
You're one up on me brother, I won't give him the satisfaction of any views. I have a negative tolerance for conspiracy asshats.

If he's that mis-informed on aviation history, I can only imagine what kind of bullshit he spews about cars that's totally wrong.

Hell, I wouldn't be surprised if half of his followers were flat earthers.
 
Last edited:
Got agree with that observation. The RAF's pre war designed 'heavies' were *supposed* to provide effective mutual support and protection using their powered turrets and were operated well beyond the range of any available escort (which were all essentially interceptors without range as a critical design criteria)

It would have been interesting to have seen the debate address why the USAF didn't spot the clear lesson that experience of the early Wellington raids should have taught - it was arguably as well armed as the near contemporary Fortress 1 (which only had manually operated guns in single mountings). Festooning bombers with even more .50s and armour and dropping their speed, altitude and range/bombload seems like a perverse way of addressing it.

There's an old British saying that maybe Greg should consider 'Cock-up not conspiracy'. There's another one that might apply too - 'Beware ascribing malice to anything that might merely have been a mistake'.

Its been my observation that people who regularly like to ignore both those truisms usually have a few tinfoil hats in their top-drawer. Or maybe in the 21st century, its all about the clicks and views, and not necessarily about the veracity of the evidence or the clarity of the argument...
 
Last edited:
It was decided in June 1943 that deep penetration raids would be escorted by fighter escorts, but that took time to arrange. The raids on Schweinfurt were therefore against this new doctrine. If the Schweinfurt raids had not taken place then 80 years after the event we would have Youtubers proclaiming that "ass hat generals" had missed the chance to shorten the war by a year because they were wedded to the idea of "escort fighters" when there was ample evidence that a surprise attack by 300 self defending bombers would have taken out Germany's ball bearing industry with high but completely justifiable losses, considering the war would have been shortened by a year.
 
29 September 1939, 11 Hampden in 2 formations, the second of 5 intercepted, all shot down.
3 December 1939, 24 Wellingtons attacked warships, intercepted, no losses
14 December 1939, 12 Wellingtons, found convoy, spend 30 minutes trying to set up bombing runs in poor weather, 5 lost to flak and fighters
18 December 1939, 24 Wellingtons, bombed ships from 13,000 feet, perfect visibility, 12 Wellingtons lost, 2 fighters reported shot down.
Blenheim reconnaissance flights 20 September to 25 November 1939, 37 sorties, 7 lost.

The USAAF was aware of the early RAF raids, but noted the following would reduce casualties
1) Self sealing fuel tanks (The Wellingtons did not have them in 1939)
2) Increased defensive firepower including effective range, 6x0.303 inch versus 10 or more 0.50 inch
3) Tighter formations
4) Larger formations and/or raids.
5) Heavier airframes being harder to shoot down (Wellington Ia and Ic overload weight was 30,000 pounds)
6) Flying 10,000 feet or so higher
7) Flying faster, the Wellington Ia and Ic top speed was around that of the B-17/24 fast cruise speed.

Similar logic used when considering the Luftwaffe day raids on Britain in 1940

Without escorts present the interceptors had more performance available to trade off for firepower. A rule of thumb is in 1943 the 8th AF heavies shot down around 2 fighters for every 3 bombers shot down by fighters, in early 1944 that became 2 to 1 in favour of the fighters. The USAAF cause of damage reports reflecting an upgrade in average Luftwaffe fighter firepower. No doubt if figures could be calculated the ratio would move further in favour of the fighters during 1944 as more 30mm cannon were carried. During the Battle of Britain the exchange ratio was in the order of 1 RAF fighter to 3 Luftwaffe twin engined bombers, the RAF pilots had 8 rifle calibre machine guns firing at bombers weighing around 5 to 10 tons empty, the bombers single rifle calibre guns firing back but were in formation.

All the above ratios would require accurate bombing causing significant lasting damage to balance the bomber losses and/or enough interceptor losses to escorts. The USAAF calculation 300 heavy bombers being enough to drive average losses down to acceptable levels was done in 1942 at the latest and not revised, even as the defences were strengthened.

Nothing was static, radar made a big difference to bomber casualties once it was hooked up to a tracking and control system, in 1939 the German radar station phoned the airfield with what it was detecting and the fighters took a while to become airborne then were on their own. The Wellingtons were looking for shipping, not flying to a known location then returning. Think of the probable results in 1939 if it was 300 B-17E incoming, not worrying as much about bombs hitting non military targets alternatively the results in 1943 if it was 24 USAAF Wellington I incoming and waiting for absolutely clear weather.
 
You must log in or register to reply here.

Users who are viewing this thread

Total: 1 (members: 0, guests: 1)

Similar threads

M
New Build Copies Of WW2 Luftwaffe Airplanes
Replies
1
Views
605
Gnomey
Another 'Gem' from Greg - just released.
16 17 18
Replies
341
Views
18K
33k in the air
Experimental aircraft: canards of war, aviation oddities, and engineering marvels
Replies
1
Views
350
Gnomey
A
Battle of Britain Airshow Duxford 14 spitfires and 3 hurricanes big formation
Replies
5
Views
710
Gnomey
M
Aerial Video of a Current Aircraft Junkyard.
Replies
1
Views
763
Sisu
S
Menu
Log in
Register