Warbird Information Exchange

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“Knowing what’s right, doesn’t mean much unless you do what’s right.”

The F-80 shot looks like a test of wingtip mounted ram jet or pulse jet engines

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Don't make me go get my flying monkeys-

I have a 16mm WWII AAF weekly film that has a segment about retrieving downed aircraft in this manner. Sort of like the Brodie system in the film they would remove the prop from a P-51 and install a lifting eye on end of the crank shaft. There would be a rope to a set of poles and an aircraft with a hook would fly over and snag the rope and pluck the Mustang off of the ground. In the film they were trying different aircraft to see which was the best for retrieving. They used the B-17 and C-47 but I don't remember seeing the P-61.

One try resulted in pulling the nose case off of the engine. There was a good combination of the mass of the tow aircraft and the stretch of the rope but I can't recall what their preference was in the film. I should get that film transferred to video as it was great to watch. I was wondering how they talked the test pilots into this program! There is a scene where the tow aircraft snags the rope and jerks the mustang real hard. The tail is up instantly and you can see that the rudder is just a blur as it is moving so fast. He was really working hard and i bet the pucker factor was up there! Then the rope goes slack and the Mustang is slowing when the tow plane catches up and another big jerk pulls the P-51 off the ground. It was quite a show.

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On the P-80/P-51 photo-
Looks like smoke or chemical dispenser set up with the lower down spout below the tip tank.

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Rich Palmer

Remember an Injured Youth
benstear.org
#64- Stay Strong and Keep the Faith

BOOM BOOM, ROUND ROUND, PROPELLER GO

Don't Be A Dilbert!

I've seen more pics of that before, I am often wrong in my recollections due to brain fade, but my 2 cents is that it was a NACA aerodynamics test on the prop,or rather lack of it in the test. Also in the other pics I think it was a P-51D.

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Martin
Wide open & turning left.

Some more photos related to the P-51/P-80 photo posted above:

http://images.google.com/hosted/life/f3 ... 7b9d4.html
http://images.google.com/hosted/life/34 ... 52154.html
http://images.google.com/hosted/life/a9 ... e6558.html
http://images.google.com/hosted/life/43 ... a2db4.html
http://images.google.com/hosted/life/f9 ... 5dfb0.html
http://images.google.com/hosted/life/fb ... 839e9.html
http://images.google.com/hosted/life/e7 ... 48f3d.html (P-80's and an Invader)

Those appear to be an H model in your links.
Orig photo in this thread looks like D model.

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Rich Palmer

Remember an Injured Youth
benstear.org
#64- Stay Strong and Keep the Faith

BOOM BOOM, ROUND ROUND, PROPELLER GO

Don't Be A Dilbert!

Rich, that may or may not be the case, but they all come from the same "Life" set (along with a few others of just the P-80 alone - note the 5th linked image, is the same as posted).

Just making a point looking at the leading edges as a reference. Straight line for the H and swept inboard cuff on the D.
Also the H models appear to have gun holes covered on the leading edges.
Pretty cool stuff either showing off for the camera or on a comparison of type mission.

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Rich Palmer

Remember an Injured Youth
benstear.org
#64- Stay Strong and Keep the Faith

BOOM BOOM, ROUND ROUND, PROPELLER GO

Don't Be A Dilbert!

Do you know how the P-51 landed, did they cut the rope somehow?

Thanks,
Phil

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A man's got to know his limitations.

Ok, looking at it again, along with the other photos in the series,it must be some sort of test to see if the P/F-80 could be used in ground support for vision obscuring smoke for troop movements. I believe the towed airplanes all used a version of the CG-4 troop gliders pintle release to drop the tow cables then the towing airplane probably dropped it's ends of the cables right after seperation as they would be flailing around and presenting a real hazard to the tow aircraft and no fun to try to land with.

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Don't make me go get my flying monkeys-

Yeah, probably another variant of All American Aviation's retrieval system they developed with the AAF, though the towline was probably reeled in on a spool after letting go of the towed aircraft. Gliderman1 may be able to shed a bit more light on this aspect if he's around.

October 1945 All American Aviation's Engineering and Development division won the Army-Navy E for excellence for their contributions to the war effort. They were especially cited for their actions in refining the Brodie system to the success it was, glider pick-up, and human pick-up innovations.

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DBF

Yes, the P-61 would have to have a tow release built into each side to connect the tow lines and to release them before landing. This would have been similar to the P-38 setup used in early 1943. That long doubled tow line training the P-61 sans the P-51 would have trailed the P-61 in an arc down and below. If it flew low enough to snag a tree or whatever with the line trialing an instant crash would have resulted. The original tests for fighter recovery using the snatch were done at CCAAF in early to middle 1943 using B-23 #39-28 with model 40 winch snatching the Stinson and a BT-13. The BT-13 is in the undisplayed NASM collection and though questionable that it is the same Stinson, the Stinson is or was in the Postal Museum in DC. A pull cable to open the release was run into the cockpits and a specially made lock bar was clamped around the propeller shaft to stop the engine from rotating from the unwinding tendency of the nylon tow line.

In snatches, the snatchee had to release from the line first. The tug then had to reel in the steel cable so they could unhook the nylon tow line and drop it before landing. Under normal conditions any snatch-tug had to maintain minimum of 300 foot altitude until the line was dropped. On a conventional tow, the tug could release the line from the cockpit after the towee cut loose. Even on combat missions the tugs had specific areas for dropping the tow lines. Estimating a line drop altitude of 600 feet with tug forward speed of 120 mph minimum at drop, the line hit the ground moving downward at 60 mph and forward at least at 60 mph. With the steel plug, figure 8 link, oval link and aluminum thimble on each end of the line stay clear of the drop area!

The P-61 would not have been a snatch. It would have been a normal ground, tow, take off. At least up to middle of 1946 only the C-47 and B-17 had winches for snatching and there was only one B-17 to my knowledge. I have never seen this image before, but the double line on the P-61/P-51 is sort of the reverse of the 1944 CG-4A bi-furcated tow experiments to help eliminate glider yaw on-tow.

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Charles Day,
Silent Ones WWII Invasion Glider Test & Experiment CCAAF Wilmington Ohio

There was a NACA test of a P-51B as I recall where they towed it aloft and released it to gather drag data. They were trying to determine how close wind tunnel models were to the full size aircraft. It had no prop and all the gaps were taped over.

P-61 towing P-51, NACA tests, Muroc, circa August 31,1944, to determine if wind tunnel tests were close to the real thing.

I can not find the length of tow lines used, but it looks to be the 15/16" diameter nylon line as was used for glider snatch. Thus, the lines would have been around 225 feet long. This was not a snatch, it was a ground tow. A standard glider tow release was mounted under the vertical stabilizer with the face of the release flush with the joint of the stabilizer and rudder on each side. A cable ran from the release to the cockpit. The cockpit release handles would have to have been combined or bolted together so that both released at the same instant. Despite a single length of this line was being used for snatching the CG-13A and CG-10A gliders which weighed more than a P-51, the NACA people must have felt two lines were needed for the P-51 which weighed only about 50% heavier than a CG-4A glider. The lines running from the P-61 to the P-51 are two separate lines. The tow lines on both ends appear to be a standard glider tow line with aluminum thimble to which an oval link and a figure 8 link are attached.

On the P-51 nose a special hub cover was made to enclose the tow release mounted on the end of the propeller shaft. Looks to be a standard "D" ring release plug connected with oval links to a pulley (approx 8" diameter). A steel cable (approximately 3/8" diameter and approximately 15 feet long) rode through the pulley. One nylon tow line connected to one end of the steel cable, the other nylon line to the other end. This was apparently to minimize the effect of the P-61 yaw on the P-51. A cable ran from the tow release to the cockpit so the P-51 pilot could release the tow line. NACA must not have liked the shorter yoke and single tow line assembly that had been developed for the P-38 to counteract the P-38 tail yaw.

Apparently there were four flight tests and the first three went fine. The fourth one did not. The information I found did not state the cause of the tow line release by the P-61-- only that it was a simple fix. The tow lines released from the P-61 while under tow and of course shot back to the P-51. The double tow lines made doubly sure to wrap around wings of the P-51. The pilot managed to land but just barely and though it did not hit any trees the P-51 looked worse than a CG-4A looked after it hit trees and hedgerows in Normandy.

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Charles Day,
Silent Ones WWII Invasion Glider Test & Experiment CCAAF Wilmington Ohio