Schweinfurt Raids & Escorting Aircraft

[KJ_Lesnick]

I've probably beaten this one to death but I'm looking at a site
URL: http://www.wwiiaircraftperformance.org/p-47/p-47.html

I LOVE IT!

There's just a couple of things I need to know for good performance computations

• What variants of the P-47 were used during the first and second Schweinfurt Raids?
  
• Why in both cases were the P-47's carrying no drop tanks in most if not all cases?
  
• What cruising speeds were generally used for escorting bombers?
  

[The Wooksta!]

Use google.  That's what it's there for.  People here are modellers, not engineers.

[KJ_Lesnick]

TheWooksta!

1. I have looked for this except there doesn't seem to be anything coming up of use
2. Many of the people here have overlaps with the Secret Projects forum

[wuzak]

Drop tanks may not have been available at the time, or the P-47s weren't set up to use them.

Certainly drop tanks were not official USAAF policy during the development period of the P-47. Drop tanks only became available as soon as they did because Kelsey went against policy and asked Lockheed to design and construct some.

[KJ_Lesnick]

Wuzak

Drop tanks may not have been available at the time, or the P-47s weren't set up to use them.

I decided to do a larger search: The first drop-tanks were available at the time of the raids but were not pressurized and could not be used above 10,000 feet.

1. Could the P-38's tanks have been kluged onto the P-47 (they were being produced as early as 1941-42)

2. Could these tanks have been pressurized for use over 10,000 feet?

It does admittedly make sense why they first P-47 drop-tanks were not used with the various flaws; however a new 75-gallon version was introduced at the end of August 1943 which would have made possible a more successful second-raid (though truthfully, it seemed pointless)

Certainly drop tanks were not official USAAF policy during the development period of the P-47. Drop tanks only became available as soon as they did because Kelsey went against policy and asked Lockheed to design and construct some.

That I know, weren't they ready as early as 1941 or 42?

[Captain Canada]

Prob had drop tanks when they took off and dropped them

[wuzak]

I'm not sure if the P-47s used drop tanks for either Scheinfurt mission, but I'm sure that if they could be used they would have been.

Also escorting the first mission were Spitfires. Perhaps if they had invented FiCon earlier they could have carried some Spitfire IXs or XIIs into theatre to help with bomber defence.

[KJ_Lesnick]

Prob had drop tanks when they took off and dropped them

Why would they do that?

[sandiego89]

Prob had drop tanks when they took off and dropped them

Why would they do that?

Uhhhh, maybe because drop tanks can be dropped.....

Seriously, empty drop tanks cause extra drag and weight, thereby decreasing range, speed and agility.  For many missions the fighters would retain the drop tanks so they can be used again, only jettisoning the empty tanks if they needed to for a dogfight, or for max range- again to get rid of the drag after the had used up the fuel in the drop tank.  Normal practice would be to draw fuel from the drop tanks first.  

Most main US fighters used drop tanks on most missions, especially longer range escort missions.  The effect the tanks had on drag and maneuverability differed considerably by aircraft, size of the tank and mission profile.  Some aircraft were more common to drop their tanks- I believe the P-51 would fit this example.  I would think that the P-47 would be one of those less effected by keeping the tanks on- a few extra pounds and extra drag would be less noticed on such a big aircraft.  Drop tanks would commonly be dropped upon seeing enemy aircraft prior to engagement or before conducting a ground attack to give increased speed and maneuverability.  At some stages of the war, and in some more austere theaters, there were drop tank shortages, so crews would be inclined to not jettison them as readily.  Even paper tanks were experimented with and used, to get around the expense and logistics with jettisoning bunches of metal tanks.      

I have no idea what drop tanks were used (or jettisoned) for this mission.  

[wuzak]

It also depends on the opposition. One plane may still be superior to another with drop tanks in place.

For example, the Spitfire XIV was judged, in tactical trials, to be superior to the Fw 190 with BMW engine and the Bf 109G in all measures at all altitudes carrying a half full 90 imp gall slipper tank. The slipper tanks didn't look too aerodynamic either.

But, for the USAAF it was SOP to drop the tanks before engaging in combat.

[wuzak]

Here are a couple of reports from the Schweinfurt missions:

https://353rdfightergroup.wordpress.com/2012/08/29/mission7-and-8-august-17-1943-the-groups-first-confimed-victory/

https://353rdfightergroup.wordpress.com/2012/10/26/mission35-october-14-1943-target-schweinfurt/

No mention is made about drop tanks either way.

The site about the 56th FG mentions when they first used certain drop tanks:

12th August 1943
Todays Ramrod to Gelsenkircken sees the first use of drop tanks by the 56th Fighter Group.
200 gallon "ferry tanks" are used. The tanks prove to be unstable and due to their inability to be pressurised
are of no use at high altitude.

23rd August 1943
Schilling leads the group for the first time. Today's mission is recorded as being the last using the 200 gal "Bathtub" tanks.

25th August 1943
Work commences on the installation of fusalage shackles on the P-47s to enable the use of pressurised 75 gallon drop tanks.

26th November 1943
On a Ramrod to Bremen the 56th uses the 108 Gall drop tanks for the first time.

20th February 1944
The Ramrod to Leipzig today sees the first use of the new 150 Gal drop tanks by the 56th.

And an alternative use for drop tanks

25th July 1944
Another "droopsnoot" mission with Schilling leading 35 P-47's and Col Zemke flying the P-38 the group take off at 18.20.
Each P-47 carries a 150Gal drop tank filled with oil, with the targets including a fuel dump at Fournival.
The group is warned of an impending attack and jettisons the tanks. When the attack fails to materialise
they content themselves with strafing the original targets.
Zemke's P-38 is hit by flak over Montdidier and he returns to Boxted minus the starboard propeller.
On landing the P-38s brakes fail and Zemke ends the mission in a field at the end of the runway.

http://www.56thfightergroup.co.uk/history.htm

[PR19_Kit]

For example, the Spitfire XIV was judged, in tactical trials, to be superior to the Fw 190 with BMW engine and the Bf 109G in all measures at all altitudes carrying a half full 90 imp gall slipper tank. The slipper tanks didn't look too aerodynamic either.

AFAIK it was SOP to drop the Spitfire slipper tanks after emptying them as, apart from the drag issues, they moved the CG to the detriment of maneuverability.

[MikeD]

AFAIK it was SOP to drop the Spitfire slipper tanks after emptying them as, apart from the drag issues, they moved the CG to the detriment of maneuverability.

I'd imagine the thought of what an incendiary, tracer or explosive round hitting a large tank full of fuel vapour will do to a pretty small plane would also help encourage pilots to dump them asap if they're likely to meet any of the neighbour's kids in their planes.

[KJ_Lesnick]

sandiego89

Uhhhh, maybe because drop tanks can be dropped.....

Oh, I thought they dropped them right after they took off!  I didn't understand that they just carried them until they ran out of gas; then punched them off the way you said it.

Normal practice would be to draw fuel from the drop tanks first.

This I'm actually aware of, the P-51 was one of the exceptions because the center tank ended up shifting the CG too far aft, so they would use that first and then switch to the drop tanks


wuzak

For example, the Spitfire XIV was judged, in tactical trials, to be superior to the Fw 190 with BMW engine and the Bf 109G in all measures at all altitudes carrying a half full 90 imp gall slipper tank. The slipper tanks didn't look too aerodynamic either.

They looked decent enough though it gave the plane a bit of a belly...

But, for the USAAF it was SOP to drop the tanks before engaging in combat.

Well, it makes sense from the standpoint of pure maximization of agility: Of course if you could maneuver well enough with them on and couldn't make the range without, it'd be best to hang onto them.

12th August 1943
Todays Ramrod to Gelsenkircken sees the first use of drop tanks by the 56th Fighter Group.
200 gallon "ferry tanks" are used. The tanks prove to be unstable and due to their inability to be pressurised
are of no use at high altitude.

Yeah, I mentioned that above as I did a little looking into drop-tanks available: I'm curious if the slipper tanks used on the Spitfires were pressurized for high altitude use earlier...

25th August 1943
Work commences on the installation of fusalage shackles on the P-47s to enable the use of pressurised 75 gallon drop tanks.

So, they were available by October...


MikeD

I'd imagine the thought of what an incendiary, tracer or explosive round hitting a large tank full of fuel vapour will do to a pretty small plane

It'd blow it up... There's footage of an Me-109 getting struck in it's drop tank. 

The tank blew up with a respective blast, a wing came off and the plane spiraled into the ground.

[tahsin]

"Oh, I thought they dropped them right after they took off!  I didn't understand that they just carried them until they ran out of gas; then punched them off the way you said it."

You would certainly go ahead a lot more if you avoided stuff like this.

Those belly tanks would be avoided whenever possible, now that RAF simply devastated a few 110s that had them during the Battle of Britain.