B-17 tail stinger mystery

[mustangdriver]

While visiting the shop at the NMUSAF Roger was showing us the tail stinger on the Memphis Belle. There are two lights under the tail guns on the stinger and the Belle's has a modified set up. Can anyone shed some light on the use of this modified light? I attached a link to a war time photo that I think belongs to our own Mark Allen.

http://s1337.photobucket.com/user/Mark_ ... d.jpg.html

[Steve Nelson]

I've been curious about that myself. There have been a couple of discussions about on facebook about it, but as is typical with FB the threads quickly got overwhelmed by inane and irrelevant "b17 r kewl lol" type posts.

SN

[Taigh Ramey]

I’m sorry I don’t have specific knowledge of that light. All I know is there were different bomb door/release lights on the back of the bombers for formation bombing and this may be an early version.

Door open white light, upon bomb release the white went out and the red went on for 5 seconds or so then back to white as long as the doors were still open.

I have seen different versions of the light mounted back there from a basic separate red and white to a combined single light with a solenoid operated colored sleeve to change the color. I am guessing that this might be one version to switch from red to white. It is interesting to try and figure out what the control is for that goes to the middle.

Sorry I couldn't be more help but I would sure like to know too!

[mustangdriver]

The NMUSAF has recreated it for the Belle, they are just trying to find out more about it.

[Steve Nelson]

One of the more relevant commenters on the Facebook thread said the "quad light" mod appears to be specific to the 91st BG.

SN

[mustangdriver]

I thought that too. I have found some 381st B-17's with it too. I think it has something to do with being a lead ship.

[Nathan]

Blink white tells the formation to get closer to the leader. Red light tells formation to loosen formation? Just a guess.

[Taigh Ramey]

I think the only controls the bombardier has over these lights are rheostats to brighten or dim them. As far as I know there are no capabilities to use them as signal lights unless there is a specific theater mod.

[Xrayist]

I believe that these are brake lights to comply with a NTSB regulation. Sorry, just had to add a remark like this!

[dirtysidedown430]

I know that all bombers had Grimes position lights on the upper tail and wing surfaces. A look at a wire diagram should tell what those lights meant and who controled them

[mustangdriver]

Mystery solved via Facebook. It was a form of IFF. They would be given a color for the day to flash.

[Taigh Ramey]

It sounds like you are referring to the recognition lights. A red, green and Amber light on the bottom of the aircraft and a white one on top that the pilot controlled to give the code of the day. What reference was given that this was part of the recognition light system?

[RAMC181]

I'll wait for Karl to post up the relevant Cheyenne Mod Center drawings that have hopefully helped close this case before going into too much detail, but from their titles and the particular setup it would seem this installation was to comply with the RAF's Resin Light rear-pointing low-intensity visual IFF system required in the skies over the UK at that time.

[mustangdriver]

Thanks to the gang on the facebook thread they were able to find drawings for this and this explanation.

S.D.158(1) 'Routing, Recognition and Identification of Aircraft', Section 5:

"14. (i) During the hours of darkness (viz. from half an hour after sunset until half an hour before sunrise) all friendly aircraft (except those mentioned in sub-para (ii) below) are to display recognition lights of approved design in the circumstances mentioned in sub-para (iii) when flying over the areas specified in sub-para (iv). These lights consist at present of coloured lamps in each wingtip and are known by the code name "Resin" lights. The lights are normall coloured red, green and yellow but in some aircraft white takes the place of yellow.

(ii) The following aircraft are not obliged to display "Resin" lights -
(a) Single engine aircraft.
(b) Twin engine night fighters when actually in process of intercepting
(c) Lysanders
(d) Flying boats.
(e) Biplanes.

(iii) "Resin" lights are to be displayed in the following circumstances:

(a) By any aircraft (except those mentioned in sub-para (ii) above and bomber aircraft proceeding to or returning from a mission) flying over Great Britain at a height exceeding 5,000 ft.
(b) By bomber aircraft on operational missions when flying over Great Britain at a height exceeding 8,000 ft.
(c) By any aircraft (except those mentioned in sub-para (ii) above) on an operational mission when flying over the sea-area defined in sub-para (iv)(b) below at a height exceeding 9,500 ft."

[p51]

One of the more relevant commenters on the Facebook thread said the "quad light" mod appears to be specific to the 91st BG.

It was. I've talked with plenty of 91st BG vets over the years and many told me of a set of lights made for the tails specially by their own people. Seems that about the start of 1944, they stopped adding them as they couldn't keep up with the losses and new planes (though the reason is just a guess on my part).
I never thought to ask how exactly they worked, though, sorry.