Bomber escort logistics?

[OldSkeptic]

The Corsair had a dramatic drop off in power at 25000 feet, although not much worse than the P-51D, but significantly more than the P-51B with critical altitude at 29000 feet.

There was reason for that, the 51D used the -7 engine, which was equivalent to the Merlin 66, the middle altitude version, compared to the -3 on the 51B which was the high altitude one. That was (as for the LF Spits) because most combat took place at those altitudes and having that better performance at the middle altitudes (as opposed to the high ones) was more useful, especially against the 190s.

 

[drgondog]

There was reason for that, the 51D used the -7 engine, which was equivalent to the Merlin 66, the middle altitude version, compared to the -3 on the 51B which was the high altitude one. That was (as for the LF Spits) because most combat took place at those altitudes and having that better performance at the middle altitudes (as opposed to the high ones) was more useful, especially against the 190s.

To be totally accurate the P-51B-1 and -5 had the 1650-3 'high altitude' merlin with Critical Altitude at 29000 feet. The P-51B-7 and -10 and -15 all had the P-51D 1650-7 which had CA at 24000 feet.

 

[wuzak]

Regarding the escorts forming up, could they not do that on the way to target?

In other words, their climb out is heading towards the RV point, and not orbiting the home airfield to join up with squadron mates.

 

[davparlr]

prior to 1944, both the F4U and F6F will not be able to control the air above 25k. While they can fight reasonably well at bomber altitudes, 20-25k, it would be difficult for them to deal with the Luftwaffe diving through the bomber formations. The P-47D could control the high road. A better solution to the pre '44 escort problem would be to add internal fuel to the P-47, if possible, not send in F4Us and F6Fs, in my opinion.

 

[drgondog]

Regarding the escorts forming up, could they not do that on the way to target?

Practically speaking - no, for a variety of reasons. First is the necessity to count the flock with respect to disposition of spares. Second is the integrity of the Group with respect to navigating through cloud cover and bad weather. Third is entrustment of navigation to the Group leader and ensure highest probability of getting the force intact to the R/V

In other words, their climb out is heading towards the RV point, and not orbiting the home airfield to join up with squadron mates.[/QUOTE]

The SOP for bombers was essentially the same except for the necessity of positioning the large group gaggle within a division bomber stream. The fighter group task was to be at the right place and time for the right box within a long trail. The fighter group challenge, once intact, was easier because the fighter is much faster and has the flexibility to navigate away from the stream - while checking over the tail symbols to make sure they had the 'right' group.

Whether Fighter or bomber group, the single most important aspect of the strike was to assemble all the pieces per plan and navigate to the target.

 

[tomo pauk]

Indeed, P-47 looks like a better tool for ETO, 1943-45.
Not just that it was faster some 40-30 mph between 25 and 30 kft, it was carrying more of protected fuel. What it was lacking in 1943 were drop tanks to extend the range (though a 65 gal increase gave handsome addition to the escort radius). 8th AF tried half-full ferry tank (~100 gals) that was to be dropped when the plane is at 15000 ft, as well as with standard 75 or 110 gal drop tank. Even with a 205 gal tank, made of resinated paper, that was found as unfit for use. Such early P-47s were good for some 375 miles of escort radius. The 5th AF seem to have had more success, with 200 gal belly tank made in Brisbane, Australia, by Ford IIRC; produced from Aug 1943.
Interestingly enough, some P-47s were flown in the Aug 1943 in the UK via Island, with 2 x 150 gal drop tanks attached. With such amount of fuel (305 + 300 gals), AHT gives 425 miles of combat radius for the P-47Ds; it's 600 miles for P-47Ds that have had 370 + 300 gals.

 

[davparlr]

Indeed, P-47 looks like a better tool for ETO, 1943-45. ....

I am not sure there was sufficient drive in the AAF to provide long range escorts in '42-'43. If there were, as there was in Fall of '43, I think they could have provided an extended range P-47 earlier.

 

[Milosh]

Crowded skies

 

[OldSkeptic]

Good one Milosh, yep there were quite a few collisions. Esecially given the (usually rotten) weather.

 

[Milosh]

Theoretically the Tempest could have provided long range escort when fitted with 90gal d/ts but would have the same problem regarding altitude as did the F6F and F4U.

 

[stona]

That assembly diagram is scary. It doesn't represent a very large area for a lot of aircraft. For the non-Brits, from Leicester to Norwich, as the crow flies, is about 100 miles.
Cheers
Steve

 

[drgondog]

In spring 1945, 2000+ bombers and 1000+ US fighters were overlapping their assemblies. O March 24, combine That number with the 500+ C-47/C-46 plus gliders for just the US Airborne troops headed for the Rhine crossing.

 

[GrauGeist]

A friend of mine, who was a B-24 pilot based out of England, said assembly was often scarier than actually being over Germany.

Climbing into the overcast, he would occasionally see shadows pass right overhead or directly in front of him (he said he lost count ofmthe near misses they had) and once in a while, there would be a bright flash briefly illuminating the clouds that was the result of a mid-air collision.

Once he cleared the overcast, the spectacle of all of the bombers assembling was almost beyond description.

Definately not a job I would have preferred...

 

[tomo pauk]

Theoretically the Tempest could have provided long range escort when fitted with 90gal d/ts but would have the same problem regarding altitude as did the F6F and F4U.

I'd say that opposite was true - Tempest was capable for 420+ mph at 25000 ft (20-40 mph faster than F4U and F6F), but the fuel tankage is too low for a long range job. Tempest V ADS gives range of 680 miles (internal fuel only; most economical cruise - 295 mph), after warming up, take off and climb (uses ~ 40 imp gals of internal fuel). So it's some 120 imp gals for those 680 miles left (5.66 milef for gallon) . For every 5 minutes on combat power, 105 miles are to be subtracted from those 680 mi. 15 minutes of combat - 315 miles less, or total of 365 miles to return home and land immediately. Here.
British were modifying the Tempest, adding the 30 imp gal fuel tank in the right wing (only one wing LE tank was present in 1944, I'm not sure how many were actually modified before the war ended). With that fuel, the range was increased by 150-260 miles (depending whether and how big the DTs are carried). 150 gals should yield 850 miles; subtracted by 315 miles it should give 'return radius' of 535 miles.

 

[Aozora]

That assembly diagram is scary. It doesn't represent a very large area for a lot of aircraft. For the non-Brits, from Leicester to Norwich, as the crow flies, is about 100 miles.
Cheers
Steve

Fortunately its all flat! I've been told that molehills are the highest natural feature...although it is rumoured that some trees do exist.

The 8th AF used "assembly ships" brightly painted, war weary (usually) B-24s as an aid to getting the various Bomb Groups formed up

 

[davparlr]

Super cool!

 

[GrauGeist]

Jimmy Stewert flew a Judas Goat with his group across the channel on D-Day...how's that for gutsy?

 

[Neil Stirling]

Americas Hundred Thousand page 600.

P51 D
Fuel 269 US gallons internal + 2 75 gallon drop tanks = Combat Radius 700miles.

Conditions:-
Warm up and take off = 5 minutes normal rated power.
Climb to 25,000ft normal rated power no distance included.
Cruise out at 25,000ft at 210. I.A.S (about 315mph)
Drop tanks.
Cruise back at 25,000ft at 210mph I.A.S
30 minutes reserve at minimum cruise.
Combat 5 minutes Wep and 15 minutes Military power.
Takes no account for decreased fuel consumption during decent.
No allowance is made for formation flight or evasive action other than 20 minutes combat.

F4U-1 Corsair (no wing tanks) I.A.W. Pilots Manual page 50 and 63

Total fuel including 154 gallon drop tank 391 gallons.

Warm up and take off 18 gallons
Climb to 25,000ft 64 gallons ( difference split between Combat climb and Ferry climb)
Combat 5 minutes wep and 15 minutes military power 91 gallons
30 minutes reserve at minimum cruise = 21 gallons

Total = 194 gallons.
391-194 = 197

197 gallons at 315mph at max cruise at 26,000ft (82 gallons per hour) 197/82 = 2.4
2.4 * 315mph = 756
756/2 = 378 miles.

F4U-1 combat radius = 378 miles.

Or in other words 54% of a P51-D.

Neil.

 

[syscom3]

Once he cleared the overcast, the spectacle of all of the bombers assembling was almost beyond description.

I heard the same thing too from a B17 tail gunner.

 

[bob44]

Did not know about those high visible painted bombers. Very cool.
Thanks for the information from Americas Hundred Thousand.