Tail warning radar on P-51 ?

[pbehn]

How many gallons is 400Ibs of fuel ? When discussing the P51 with the rear tank full I have read many say it was tricky to fly, I never read about the additional weight of the radar though. It seems inconceivable they would put another 400 Ibs in the plane let alone in the back of it.

 

[davparlr]

Although I can't prove it, I think the weight of the radar in the P-61 was about 400 lbs. I don't think they would ever put a gizmo that heavy in a fighter if it wasn't a sure thing.

 

[FLYBOYJ]

How many gallons is 400Ibs of fuel ? When discussing the P51 with the rear tank full I have read many say it was tricky to fly, I never read about the additional weight of the radar though. It seems inconceivable they would put another 400 Ibs in the plane let alone in the back of it.

66.45 gallons. 1 gallon of avgas weighs 6.02 pounds.

 

[stona]

I think the P51 radar to be more like Monica which was also used by Bomber Command and which was abandoned after it was discovered that German night fighters were attracted to its beams.

The AN/APS-13 tail warning radar was the US version of Monica. It's a very similar thing. I'll try and find a weight, but it was definitely not 400 pounds.

I doubt that the P-51 manual would describe radar equipment weighing 400 pounds as 'light weight'

This is the system.

Here's what is inside the unit.

This along with the panel in the cockpit is all you need. If the whole system weighed more than 20-30 pounds I'd be amazed.

Cheers

Steve

 

[drgondog]

View attachment 250176The tail warning radar was used as an "off the shelf" item for fusing of the the Atomic bombs used on Japan. This was to ensure an air burst no matter what the barometric pressure was.
Photos of the very early bombs show the radar antennae and replicas include them to varying degrees of accuracy.

According to other documentation - four were used with two required to validate the ~1300 AGL fuse height.

 

[FLYBOYJ]

The link was posted earlier...

"I. INTRODUCTION.



1. Verbal instructions were received by Fighter Interception Unit from Air Defence Great Britain to carry out trials of A. N. A. P. S. 13 as a method of range finding in Tempest aircraft, operating against Flying Bombs at night. A Tempest V aircraft, fitted with the equipment, was delivered from Defford to the F. I. U. Tempest Detachment at R. A. F. Newchurch, for trials, at the end of July.



II. DESCRIPTION OF EQUIPMENT



2. The A. N. A. P. S. 13 consists of a Unit of approximately 15" by 8" by 10" overall dimensions, mounted on the port side of the aircraft behind the pilot. The pilot's control box is mounted on the starboard knock out panel and carries an on/off switch and a test switch for the indicator lamp, which is mounted near the gun sight. The indicator lamp will light up at a range, which is pre-set on the ground. A single dipole aerial is carried on the port wing near the wing tip. The overall weight of the equipment is approximately 25 lbs.

III. NATURE OF TRIALS



3. Since returning from Newchurch to Wittering for adjustment, the equipment has been flown six times by day and six times by night by the F. I. U. Tempest detachment. The day trials have been carried out on target aircraft, owing to the shortage of Divers when required; but all the night trials have been done with Divers as targets.



IV. RESULTS OF TRIALS



4. When the aircraft was delivered from Defford the range was pre-set at 800 yards and the light was permanently on at low levels. The aircraft was returned to Wittering where the range was set at 300 yards and the aircraft returned to Newchurch.



5. During each of the twelve test flights the warning lamp came on at ranges of 300 to 350 yards, or when flying at less than 1500 feet above the ground. The light remains on to zero range. The dimming of the bulb is considered adequate.



V. CONCLUSION



6. As the equipment is small, and extremely easy to operate, it is ideal for Tempest aircraft. The present range setting is just within the firing range and should remain as it is. It gives no indication of closing speed, but this is not important, as the pilot can tell whether he is closing by the increase of the intensity of the flame from the propulsion unit of the bomb.



VI. RECOMMENDATION



7. The pilot's control panel and cabling is at present installed on the emergency jettison panel and in this position might cause difficulty in abandoning the aircraft. It is suggested that this unit be moved to a position on the same side of the fuselage above the petrol cocks.



10th August 1944.
FIU/S. 505/ 16/ AIR Squadron Leader,
Commanding Fighter Interception Unit,
Royal Air Force, Wittering"

http://www.hawkertempest.se/ElectronicWar.htm

 

[stona]

25lbs, thanks for that.

I made a pretty good guess even if I say so myself

Cheers

Steve

 

[Airframes]

Good stuff Joe, and a good 'guesstimate' Steve.