Why were U.S. pursuit fighters at the start of WW2 of lower performance than European fighters? (1 Viewer)

[Shortround6]

P-51 behind fo' sho.

And under.

Now maybe the top of the wing was enough separation between the fuel tanks and the cockpit but they were under cockpit.

 

[SaparotRob]

Below the ashtray.

 

[marathag]

Note 'flames of blow-torch intensity thru the instrument panel at the pilot' I do think this is a mid-late production Mk I, since it has the seat armor and armorglass, and three blade prop

Did the RAF think enemy bombers wouldn't be shooting back at their attacker?

The forward tank looks close to where the CoG should be, but do wonder if the cockpit be moved forward and fueltank moved aft to keep similar balance

 

[z42]

The forward tank looks close to where the CoG should be, but do wonder if the cockpit be moved forward and fueltank moved aft to keep similar balance

Not possible. Directly ahead of the pilot's feet is the firewall, ahead of that is the supercharger and carb. The fuel tank is above the feet and the supercharger.

 

[drgondog]

And under.
View attachment 716130
Now maybe the top of the wing was enough separation between the fuel tanks and the cockpit but they were under cockpit.

The top of the wing was 'uncovered' for NA-73X through NA-99 (P-51A). When the wing dropped 3 " for the XP-51B and all successive models, a floor was added to protect coolant and aft fuse fuel lines from clumsy feet.

 

[marathag]

Not possible. Directly ahead of the pilot's feet is the firewall, ahead of that is the supercharger and carb. The fuel tank is above the feet and the supercharger.

from a model kit

Looks to me like there was room to move forward some, but would leave some space above the legs, as you point out.

But why the desire to put a gravity fed fuel tank there, and not the oil tank/glycol tank or cowl guns, as other nations did with that area?

Why not move the cockpit forward some, and relocate the oil tank from by the wing to ahead of the instrument panel, and have the reserve tank just behind the seat, with the radio gear ontop?

What this would look like, is similar to the P-51 layout

The goal is to keep fuel from a punctured fuel tank from streaming into the cockpit by the windstream.

Yeah, hot Oil and/or hot glycol would not be an enjoyable bath either, but worlds better than the 'Blow torch intensity flame'

At 600 yards, too far away to register, Page opened fire on one of the leading machines, then abruptly stopped short. One moment there had been clear sky between himself and thirty Dorniers. Now the air was criss-crossed with a fusillade of glinting white tracer-cannon shells converging on the Hurricanes. He saw Gracie's machine peel from the attack; the distance between Page and the leading bombers was only thirty yards now. Strikes from his machine-gun fire flashed in winking daggers of light from a Dornier's port engine; it was suddenly a desperate race to destroy before he himself was destroyed.
As a thunderclap explosion tore at his eardrums, Page's first reaction was: I can't have been hit. It could happen to other people, but not me. Then all at once fear surged again as an ugly ragged hole gaped in his starboard wing. And then the petrol tank behind the engine, sited on a level with his chest, blew up like a bomb; flames seared through the cockpit like a prairie fire, clawing greedily towards the draught from the open hood. A voice Page barely recognized was screaming in mortal terror: Dear God, save me — save me, dear God.'

Desperately he grappled with the Sutton harness, head reared back from the licking flames, seeing with horror the bare skin of his hands on the control column shrivelling like burnt parchment in the blast furnace of heat. Struggling, he screamed and screamed again. Somehow — he would never know how — he extricated himself from the cockpit, and began falling like a stone, powerless to stop.
Richard Collier Eagle Day - The Battle of Britain Hodder & Stoughton 1966

 

[marathag]

The forgotten fighter plane which won the Battle of Britain

Eighty years ago, a small single-seat fighter was largely responsible for defeating Germany’s attempts to invade Britain. But it wasn’t the Spitfire.

www.bbc.com

A mix of design defects and pilot habits created one particularly gruesome problem with Hurricanes. At first, the aircraft did not have armour around the fuel tanks, and nor did the tanks "self-seal" if they were punctured, something which became standard during World War Two. The doped fuselage and wooden frame could catch fire quite easily. Fuel would flow from damaged tanks in the wings to an empty space under the cockpit, but a bigger problem was the main fuel tank which sat directly in front of the cockpit. If it was ignited, it shot a jet of super-heated flame straight into the pilot's face.

Another factor compounded this. Some of the more experienced pilots at the start of the Battle of Britain had originally flown biplane fighters in the 1930s and tended to fly with the canopy open. Also, early Hurricanes had a problem with carbon monoxide fumes leaking into the cockpit, so an open canopy meant they could take their oxygen mask off (it was an incredibly uncomfortable thing to have on your face for the whole mission). "All they did by having the canopy open was the temperature would go up to several thousand degrees in about three or four seconds – it was like turning the cockpit into a blast furnace." Hurricane pilots often had only a few seconds to get out of the cockpit or face life-changing injuries, or worse.
So many pilots suffered such very similar injuries – severe burns around the eyes, and on their hands as they tried to shield their face – that British surgeons came up with a nickname for it: "Hurricane Burns". The open canopy, the unarmoured fuel tank in front of the cockpit, the tendency for Hurricane pilots to fly with an unfastened mask, all combined with agonising, disfiguring effect.

The severity of these burns cases was a huge challenge for doctors. A leading reconstructive surgeon, New Zealander Archibald McIndoe, set up a special surgical unit at East Grinstead in West Sussex to treat them. McIndoe used experimental techniques – pioneering plastic surgery – on pilots with severe burns. McIndoe's groundbreaking programme revolutionised burns care. He discovered saline water treatment helped burned skin heal more quickly after noticing shot down pilots who had been rescued from the English Channel tended to recover quicker than those who went down over land.

 

[z42]

Yup, those pilots went up there to be shot at, sitting there with a big unarmored fuel tank in their laps. Brave guys.

IIRC one thing the Brits hadn't figured out yet (but some others had, including Germany IIRC ) was to have the pilot in a more reclining position which helped with G tolerance. But as a result, the cockpit would also be shallower. So in such a case, put the fuselage tank under the cockpit?

 

[GrauGeist]

Moving the fuel tank around on an ai4frame cannot be done without serious consideration to CoG - not inly is the aircraft's CoG affected by a full tank, but it'll start shifting as the fuel is consumed.

 

[marathag]

Moving the fuel tank around on an ai4frame cannot be done without serious consideration to CoG - not inly is the aircraft's CoG affected by a full tank, but it'll start shifting as the fuel is consumed.

So where is the CoG on the Hurricane? then can be calculated how much change there is from full to empty in both locations for moving that 28 imp. gallon tank, almost 219 pounds of fuel, and weight of sheet metal tank, what, 15-20 pounds for that

there is some leeway, given a two-seater was done recently

duplicating a few that were done postwar

 

[Shortround6]

That doesn't take care of a shifting/changing CG. I have no idea what they shifted to get the rear cockpit in there. The next question is can you fly it with the rear seat empty>

SBDs were not supposed to flown (at least in the early days) with rear seat empty. Either take a crewman or strap sandbags/ballast in place. And so it can't move.
Recent conversion is probably not lugging around the war time radio

 

[Reluctant Poster]

Yup, those pilots went up there to be shot at, sitting there with a big unarmored fuel tank in their laps. Brave guys.

IIRC one thing the Brits hadn't figured out yet (but some others had, including Germany IIRC ) was to have the pilot in a more reclining position which helped with G tolerance. But as a result, the cockpit would also be shallower. So in such a case, put the fuselage tank under the cockpit?

Later model Spitfires had 2 level rudder pedals to improve G force tolerance

 

[Barrett]

Too many responses (including several excellent ones) to scan thru, but French engine development lagged in comparison to the UK and Germany. My impression is that available power limited the potential of available airframes.

The Army d'l Air's most successful fighter in 1939-40 was the export P-36, aka Hawk 75.

 

[drgondog]

So where is the CoG on the Hurricane? then can be calculated how much change there is from full to empty in both locations for moving that 28 imp. gallon tank, almost 219 pounds of fuel, and weight of sheet metal tank, what, 15-20 pounds for that

there is some leeway, given a two-seater was done recently
View attachment 716189
duplicating a few that were done postwar
View attachment 716190

The CG will be relatively close (but not on) the 1/4 chord location, in this case near the firewall I would think

 

[Peter Gunn]

As memory serves, I remember reading years ago about the original Yanks in the RAF that U.S. Olympic Gold Medalist bobsledder Billy Fiske was flying a Hurricane in the BoB when his forward fuel tank took a hit. He managed to land (instead of bailing out for some reason) but didn't survive his burns.

Just one more example of the pointless waste during war.

*EDIT*

I was correct... for a change.

Billy Fiske

 

[Shortround6]

Too many responses (including several excellent ones) to scan thru, but French engine development lagged in comparison to the UK and Germany. My impression is that available power limited the potential of available airframes.

The Army d'l Air's most successful fighter in 1939-40 was the export P-36, aka Hawk 75.

You are not wrong.
The French were developing two new/updated engines but they were not in time.
Hispano was working on the "Z" engine but even if France had not been over run it still needed a lot of work and it was not going to stay competitive for long. They needed a new V-12 and not just new cylinder heads on an old beefed up block/crankshaft.
G-R was working on the 14R engine but it too may have need a lot of work to actually make it into production. Both the engine and the manufacturing facility/s.
It used the same bore and stroke as the 14N but just about everything else was different.
G-R had an 18 cylinder engine but it was huge, 3442 cu in (54.24 liters) and very light weight (no center bearing on the crankshaft).
H-S had a large 14 cylinder radial but it too did not have a center bearing on the crankshaft. 2758cu in (45.2 liters) 1433lbs (less than a P & W R-1830).

It generally took 3-4 years to develop a new engine and 1 1/2-3 years for a major modification to an existing one.

 

[marathag]

The CG will be relatively close (but not on) the 1/4 chord location, in this case near the firewall I would think

So moving the tank close to original seat location does move the CG aft, as expected, and will add slightly to C0G changes as fuel is burned, as the wing tanks already do.

But advantage of 170 pound Pilot, his parachute, the seat and armored seatback is moving forward as well, reducing the tail heaviness caused by moving the tank aft.

 

[drgondog]

So moving the tank close to original seat location does move the CG aft, as expected, and will add slightly to C0G changes as fuel is burned, as the wing tanks already do.

But advantage of 170 pound Pilot, his parachute, the seat and armored seatback is moving forward as well, reducing the tail heaviness caused by moving the tank aft.

A great deal of thought goes into preliminary design - interactive as various fixed and consumable stores are positioned and re-positioned. The most important is the fuel and the fuel fraction as the designers/performance guys play with tankage - usually the most important consumable and most potential impact on static margins and cg travel for stability.

I would assume that the Hawker designers elected to go with their decision after exploring many options to improve hazard management for the amount of fuel required to meet the spec. Very few designers of Pursuit aircraft elected to put fuel in wings as wingtankage tended to force more weight into wing, make difficult decisions fat wing/thing wing for drag considerations, increase structural related weight, etc

 

[Peter Gunn]

A great deal of thought goes into preliminary design - interactive as various fixed and consumable stores are positioned and re-positioned. The most important is the fuel and the fuel fraction as the designers/performance guys play with tankage - usually the most important consumable and most potential impact on static margins and cg travel for stability.

I would assume that the Hawker designers elected to go with their decision after exploring many options to improve hazard management for the amount of fuel required to meet the spec. Very few designers of Pursuit aircraft elected to put fuel in wings as wingtankage tended to force more weight into wing, make difficult decisions fat wing/thing wing for drag considerations, increase structural related weight, etc

Which brings up a question about the 85G fuselage tank in the Mustang. I'm sure this is covered in the excellent tome "Bastard Stepchild..." (which, shamefully, I have not actually read yet, my apologies) but did North American plan for that possibility? I mean, what was behind the pilot (other than the radio) in the early P-51 that space could be found for that big honking fuel cell?

Or was it just a happy coincidence that that space was available?

As always, thanks.

 

[drgondog]

Which brings up a question about the 85G fuselage tank in the Mustang. I'm sure this is covered in the excellent tome "Bastard Stepchild..." (which, shamefully, I have not actually read yet, my apologies) but did North American plan for that possibility? I mean, what was behind the pilot (other than the radio) in the early P-51 that space could be found for that big honking fuel cell?

Or was it just a happy coincidence that that space was available?

As always, thanks.

radio, battery, iff.