Arming the bouncing bomb [Upkeep] before release ?

[taffy2jeffmorgan]

I did a presentation many years ago about the attack by 617 squadron on the Ruhr dams in 1943, I covered all topics of the raid, the development and the testing of the bouncing bomb, training, and the raid its self, but there was one fact that I could not find any reference too, and that was how the bombs were armed. The only closest remark that I found was one author on the subject said that the bombs would be armed by a crew member after crossing the Dutch coast, this being a precaution in case the Lancaster had to ditch and the pressure of 60 foot depth of water would explode the bomb, but seeing where the bomb was located outside the Lancaster that method would be almost impossible.  Although still not sure I think the ground crew would have armed the bombs before take off, and this would mean removing the caps or covers from the four fuses fitted to each . So if possible I would like to put this ghost to rest !!

Cheers

[jollyjack]

Wasn't it done by some wire from the cockpit ?

[BOO]

@taffy2jeffmorgan  I think previously you asked this on another forum and someone alluded to an image of on of the lancs with missing paint above the radioman's window. At the time he could only find a lower res image.

 

I think this might be the image he was refferring to. Its AJ-T. If you follow the paint scarring it looks like it leads to a small hole or cowl in the fuselage. Thats certainly not a feature of any other lanc I've seen.

 

Edited January 26 by BOO

[AndyJWest]

Do we know what sort of fuses were used? If they were similar to the hydrostatic type used on depth charges then in service, they might have had some sort of mechanical safety device, armed by pulling on a cable:

 

https://www.maritime.org/doc/depthcharge6/index.php

 

 

 

[BOO]

Some more information here - Its from the model builder but it doesnt seem to be conjecture. Itappears the cord was not to arm the mine but to engage/disengage the 65 second Self Destruct Fuse. 

 

https://forum.largescaleplanes.com/index.php?/topic/93248-132-hk-lancaster-dambusterwith-additions/page/5/

 

"Perhaps the most contentious issue surrounding Upkeep is the question of fuses and fusing, Why does it matter for the model when it can't be see? Oh believe me it does!

Upkeep had two types of fuse, three hydrostatic fuses designed to cause detonation at 30 feet and, here's the elephant in the room, a self destruct fuse to stop it falling into enemy hands. The SD fuse consisted of a rip off pin that, when pulled out of the end of Upkeep, triggered a spark which lit a length of fuse which in turn, after 65 seconds would ignite the charge and explode the mine. All very Heath Robinson but effective.

So what's the problem? Well, for many years the belief was that the pin was ripped out as the caliper arm which held upkeep in place sprung open to drop the bomb. All very well and good but, if that was the case, an accidental dropping on the ground (as allegedly happened when a WAAF pulled the release handle by the pilot's seat by mistake) would give 65 seconds to clear the aircraft before ...BOOM!

A "safety catch" was needed so the rip off pin remained un-tethered while on the ground meaning an accidental dropping would not rip it out but disengaged just after the aircraft was over enemy territory arming the SD fuse.

How that was achieved? A claw fastened to the starboard caliper arm was fastened to a cable running to the cockpit ove the outside of the airframe. This claw could either be open, and not locking onto the rip off pin, or closed and grasping it. Before take off and until over enemy territory, the claw was open. Once over enemy territory, the cable was pulled, closing the claw over the rip off pin and arming the fuse "

 

 

 

 

 

Edited January 27 by BOO

[taffy2jeffmorgan]

6 hours ago, AndyJWest said:

Do we know what sort of fuses were used? If they were similar to the hydrostatic type used on depth charges then in service, they might have had some sort of mechanical safety device, armed by pulling on a cable:

 

https://www.maritime.org/doc/depthcharge6/index.php

 

 

 

The fuse types were all Royal navy depth charge fuses so Barns Wallis did not have to look far, the hydraulic motor that cranked the bomb up to 500 rpm was also used by Royal navy submarines to operate their diving planes, the rpm gauge fitted to the hydraulic motor to show the correct spin speed was taken from a BSA motor bike. Another amazing fact was that the bomb was spun up about 30 minutes from target, how they managed to maneuver the Lancaster with almost 4 tons of bomb spinning at 500 rpm beggars belief   

I would like to thank you all for that incredible amount of information and I live in hope that one day they may do a remake of " The Dambusters "

 

Although there was talk that Peter Jackson of Lord of the Rings fame was toying with idea ?

Edited January 27 by taffy2jeffmorgan

[BOO]

5 hours ago, taffy2jeffmorgan said:

 

Although there was talk that Peter Jackson of Lord of the Rings fame was toying with idea ?

 

Theres been talk for many years. Stephen Fry worked on an early screen play draft. Jackson had replicas of I think 3 lancs built and owns the rights but the project seems to have run out of traction at present. But never say never, there are always rumors.

 

Anyhow - for now, its not anywhere near happening soon so at least we'll all be spared the wringing hands over the poor dog's name for the foreseeable. 

 

 

[taffy2jeffmorgan]

Many a true word , that poor black Labrador will never know what he started !  apparently the name given to him by Gibson is the Portuguese for black.  Thanks BOO for all that sound knowledge 

 

Cheers

[BOO]

10 minutes ago, taffy2jeffmorgan said:

Many a true word , that poor black Labrador will never know what he started !  apparently the name given to him by Gibson is the Portuguese for black.  Thanks BOO for all that sound knowledge 

 

Cheers

 It may well be but it doesnt make any less awkward that a bloke flying for the RAF was using t! 🙂 

 

BTW - probably well known but an more "fun" fact is that AJ-G was Gibson's fathers intitals (Alexander James) and its it said he selected the code of his aircraft based on that. 

[taffy2jeffmorgan]

Thanks BOO,  BTW what part of the world are you from.

[BOO]

7 hours ago, taffy2jeffmorgan said:

Thanks BOO,  BTW what part of the world are you from.

 

Manchester originally but I live 5 mins from Scampton now.