Dambusters: Building the Bouncing Bomb

[green granite]

Tonight 2000hrs Channel 4:

Dambusters: Building the Bouncing Bomb


Monday 02 May
8:00pm - 10:00pm
Channel 4

The story of Barnes Wallis's bouncing bombs and 617 Squadron's bombing raid on the dams of the Ruhr valley has been elevated to almost mythical status - mainly thanks to the 1950 film. Here, Cambridge lecturer Dr Hugh Hunt (a world expert on rotating objects) takes on the complex, dangerous task of trying to re-create the raid. It's a massive project that includes the building of a small dam in north-west Canada. At two hours, it's a long haul, but the many setbacks and layering on of tension do help give a greater understanding of the cunning and daring of Wallis.

Radio Times reviewer - David Crawford

[Trogger]

Some video preview is online here -
Dambusters documentary recreates the science behind WW2's most audacious bombing raid | Mail Online (http://www.dailymail.co.uk/sciencetech/article-1381486/Dambusters-documentary-recreates-science-WW2s-audacious-bombing-raid.html)

Looks to be an interesting programme...

[Tankertrashnav]

Thanks for the heads up Green Granite. At two hours it looks like a good one to record and watch later so you can whizz through the endless commercials.

[arandcee]

(a world expert on rotating objects)

I think I'd want a better title than that.

Frank Whittle (a world expert on noisy go-fast things)
Isaac Newton (a world expert on fally things)
Stephen Hawking (a world expert on really high up stuff)

[MFC_Fly]

Looks to be an interesting programme...
Looks to be, let's hope it is and the producers don't ruin it!

[BEagle]

A Dambusters thread without the mention of a certain black labrador?

Can This Be A Record?

[Wander00]

Beagle - you just spoiled it!

[airborne_artist]

Just don't mention the other WWII aviation film, or BEagle will need to lie down.

[diginagain]

A Bridge Too Far?

[airborne_artist]

No, BoB. BEagle's BP goes into the red at the mention of the late and lovely Susannah York.

[diginagain]

You said 'Aviation'. Surely BoB is 'Air'?

:)

[BEagle]

Ah yes......

http://i14.photobucket.com/albums/a341/nw969/sy_d.jpg

:ok:

[Union Jack]

Now why does that make me contemplate the desirability of being between a rock and a soft place - with apologies to the late lamented Miss York (and BEagle of course)!:ok:

Jack

[langleybaston]

shucks ......... need to lie down, preferably with

[SOSL]

I hope I'm wrong about this but I don't think Beags is late yet! (or lamented) I think I agree with you about
Miss York and the rock. Remember the stockings and suspenders.

[Wander00]

All hot and bothered now, just as I am trying to cook supper - I shall JUST have to go and lie down!

[just another jocky]

You guys do it lying down? :confused:

[Roadster280]

Is that the Moehnesee behind her?:E

[TEEEJ]

If you stumble across the thread and miss the start then remember Channel 4 + 1 on Sky. (Channel 135). The programme will run from 2100-2300 on Channel 4 + 1. Channel 4 +1 is also available on Freeview - Channel 13.

TJ

[BEagle]

Susannah really was so gorgeous:

http://i14.photobucket.com/albums/a341/nw969/SY05.jpg

Those eyes hinted at such....fun!

I detect something of a 'trouser moment' is beginning to stir...:\

[just another jocky]

I detect something of a 'trouser moment' is beginning to stir...:\

So will Sir be lying down for this one? :ooh:

[Landroger]

To my untrained, civilian eye, he dropped late and too low, but the big Ice Pilot got it in one. Seemed to me to be very, very smooth aircraft handling? Fascinating programme.

ROger.

[Tankertrashnav]

Great watching that guy chucking that DC4 around - same age as me too!

Seriously, I wonder how that Prof got the funding to do (not quite) what Barnes Wallis did 68 years ago. Still, I'm glad he got it, very entertaining

[NutLoose]

I detect something of a 'trouser moment' is beginning to stir...:\

Do you take water with your viagra? :p


Fascinating viewing...... The programme that is, not watching Beagle trying to get it up...........:E

[BEagle]

I'm much relieved to hear that!

[pzu]

In early part ( first 15 min) clips of 2 Post War test runs - first was 'hair raising' and second Disastrous

What type of a/c was performing test runs my guess is some form of A-26 Invader - which possibly indicates US involvement (in the Post War tests not the actual WWII mission)

PZU - Out of Africa (retired)

[Whenurhappy]

Umm, I think tests were initially conducted from a Wellington airframe. The aircraft remained in trials use well after the war. Before FI was 'invented', it was understood that the Wellington didn't fall apart as frequently as the 4 engined heavies. Of course, the geodesic airframe was also invented by Sir Barnes Wallis.

Perhaps Dr Hunt is the sort of chap, in an earlier life, would have invented similar weapons when the Realm was threatned. Garden shed, rusty nail, under-investmentand a hand-cranked generator and eh, voila! a war-winning weapon mortgaged to the US to get us out of more financial poo!

[Pontius Navigator]

BEagle, get Mrs B to repair the pockets then.

[D120A]

Fascinating programme. I had read previously about the importance of the back-spin, in that the Magnus effect on the store as it sank would have generated a force that caused it to hug the wall of the dam so that the water-tamping would do the damage when it exploded. But I hadn't realised how important the backspin was for the bouncing performance.

I'll look at my recording again but I think the commentary defined the benefit of the back-spin then as the aerodynamic lift it generated on the store (again, Magnus effect) as it travelled through the air. I think there might be another reason. We all know that pebbles skip better on water the faster you throw them. Well, a back-spinning store hitting the water has a contact speed between the two that is much higher than the simple forward speed of the mine - it's that plus the perimeter spinning speed. So the bouncing dynamics are those of a store hitting the water at a higher speed, and hence it bounces better and longer. That, plus the angular momentum of the spinning store keeping it orientated correctly make the whole concept of 'Upkeep' a triple work of genius.

I'll get back to the pictures of Miss York now. Thank you BEagle.:ok:

[Trim Stab]

What type of a/c was performing test runs my guess is some form of A-26 Invader - which possibly indicates US involvement (in the Post War tests not the actual WWII mission)


Yes, it was indeed an A-26, filmed in tests in USA after the war. UK trials were with Wellington, Lancaster and Mosquito only.

[Barksdale Boy]

BEagle, as the Prime Minister said, "Calm down, dear". You could try firing up the Weber instead. Might I recommend Louisiana Pork?

[Trim Stab]

Well, a back-spinning store hitting the water has a contact speed between the two that is much higher than the simple forward speed of the mine - it's that plus the perimeter spinning speed.


You are correct - the aerodynamic lift mentioned in the programme is fairly insignificant compared to the effect of the backspin.

The backspin gives the bomb a considerable rotational energy - when the bomb hits the water, part of this rotational energy is converted to kinetic energy in the upward bounce. This explains why on some of the videos the bombs were bouncing substantially higher than the aircraft that had dropped them.

The other part of the programme that they rather glossed over was the final drop with the "live" bomb. They implied that the explosives were contained in the bomb - but I very much doubt they were!

[BEagle]

Looz'yana pork? What's that - hog jowls smothered in cayenne pepper relish to disguise the taste?

Call-me-Dave's put-down on PMQs was priceless - no doubt the rancorous nuLabor wimmin on the Opposition benches loved it....:suspect:

The other part of the programme that they rather glossed over was the final drop with the "live" bomb. They tried to imply that the explosives were contained in the bomb - but I very much doubt they were!

I thought it was pretty clear - they merely removed the dummy bomb and placed the 'live' bomb (which had the same mass and physical properties) in the same impact location, then detonated it. Rather impressively! There was no suggestion that it had been flown under the DC-4.

[Pontius Navigator]

The water spout from that explosion was interesting as it looked a bit like the Prince of Wales Feathers with both sides of the water plume turning back in on themselves.

It was actually not that different from the artificial plume in the Dambusters where they used a horizontal flow superimposed in the vertical. If they ever make the new film I hope they learn lessons from this one.

I didn't see a dog at the airfield though so it was not that realistic.

[forget]

As our friends at Buffalo Airways are game for anything what else can we do? Here’s an idea. Find another DC4/6 and paint the pair as one 9 Squadron (I’ll provide the bats.) and one 617 Squadron. Then fit a couple of bomb sights. (See where I’m going with this?)

Next we need a Norwegian Fjord and an old freighter of around 50,000 tons. Drawings for Tallboy bombs are available at Hendon. Anything else we need to get started?

[XV490]

Interesting, too, to hear of "The Arch B*stard" - a moniker for Gibson I hadn't been aware of.

Can someone confirm that the post-Dams raid Highball bouncing bombs were nearer to being spherical than the Upkeep weapons?

[kiwi grey]

If they ever make the new film I hope they learn lessons from this one.

As far as I know, Sir Peter Jackson is still working on the new movie, though presumably it's behind The Hobbitt in the schedule. He's certainly built a bunch of Lancaster models - up to full size.
Just in case they haven't already got a copy, maybe you could drop Weta Digital (who will be doing the special effects) a line at [email protected] ([email protected])
:)

[airborne_artist]

For those that missed it, it's not on 4OD, but is on the web as a torrent.

I thought that Dr Hunt's assistant should really have been in a period uniform, complete with correct hosiery. BEags would have liked that :E

[Pontius Navigator]

Interesting, too, to hear of "The Arch B*stard" - a moniker for Gibson I hadn't been aware of.

Can someone confirm that the post-Dams raid Highball bouncing bombs were nearer to being spherical than the Upkeep weapons?

Yes it was spherical whereas the final Upkeep bomb was cyclindrical. If you watch the programme again you will hear a reference to the wooden casing and the bomb being spherical. The wooden case was discarded early on - they said.

One thing I didn't pick up from the programme was the problem they had with balance on the wartime bomb. As it was spun so the explosive had a tendency to unbalance the bomb.

Dr Hughs discovered the need for a balanced bomb but did not touch on the wartime problems.

[langleybaston]

So what was the fuss regarding height judgement on board the a/c in these experiments? Over mirror-calm water, relying on an old boy's judgement? How often in his fire-fighting role does he fly very low over water? Why not create a lop with a few high speed boat runs? Surely there are simple laser surveying tools that could be used these days? When I buy/ sell a house, the agent no longer uses tape!

Or even a weighted dangling string, calibrated against the shore-based sticks and strings


or, or, or ........

But not seat of the pants stuff, totally out of order. Valuable a/c, valuable co., never mind the old boy's drinking buddies.

I'm glad that the pilot will never get to fly me; 0/10 marks for airmanship from this simple Metman, and I can see why the good Dr. stayed on shore.

Very good documentary nevertheless, actually good on the physics and good at my [educated but not physics] wife's level.

[Trim Stab]

Also interested to know how the wartime bomb was spun. Wiki mentions that it was spun by an "auxiliary motor" - but was this electrical? Or thermic? If electrical presumably they had to modify the aircraft electrical systems fairly extensively?

[Whenurhappy]

As one who knows about such things, I wasn't at all surprised that there was soliflucation around the sides of the dam - there were no discernable abutments to anchor the dam wall to the sides of the incision. Presumably these were not deemed necessary because of the err, short operational life of the model dam.

Excellent flying in that DC4 (?) - distance shots reminded me of the CP107 Argus (based on the Britannia). I remember seeing one as a cadet in the eraly 1970s.

[adr]

In terms of telling the story, not as good as 1954, I thought, and with too much pretending-not-to-know-things.

But my hat is off to the good prof for getting a film company to fund him to have such fun with some big, expensive toys. :E

adr

[forget]

Spinning? Top of my head - Back-spin was to be initiated 10 minutes prior to arrival at a target, and was imparted via a belt driven by a Vickers Jassey hydraulic motor mounted forward of the bomb's starboard side, the motor itself being powered by the hydraulic system normally intended for the upper gun turret, which had been removed as part of the aircraft's modification.

Wiki really. :hmm:
Bouncing bomb - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Bouncing_bomb)

[xtypeman]

Don't forget from Thursday on Freeview (38) Ice Pilots the boys from Buffalo Air and big piston engines.......heaven!

Ps but not the same as Ms York.........

[BEagle]

I thought that Dr Hunt's assistant should really have been in a period uniform, complete with correct hosiery. BEags would have liked that :E

Too right! Period WAAF shirt and webbing, ooh yes....;)

I agree about height keeping. Although the pilot flew very accurately, I would have thought that a rad alt might have been advisable. The weighted dangling string idea would have been just as unsuccessful as it was in 1943 when it simply flew more or less level with the aircraft due to drag on the weight and string.

Perhaps PN might remember as he was probably around at the time, but surely the Upkeep weapon was only spun up shortly before the attack run. I seem to recall having read (or maybe I saw it on TV) that the rotation caused massive vibration through the airframe when the weapon was at pre-drop rotational velocity.

[forget]

Which reminds me. My Uncle Arthur was a Lancaster gunner with 630 Squadron out of East Kirkby; 32 Ops, 216 operational hours. Anyway, a few years after the war ended he and his brother, my Dad, were shooting the ‘breeze’ and I have a memory of one story from Arthur.

When 617’s first bombs were delivered to Lincolnshire they’d been transported in very substantial hard-wood cases. I seem to remember teak being mentioned. The intention was that the empty cases would be sent back to Vickers for more bombs. When nothing had arrived back Vickers telephoned to ask why.

The reason – some enterprising Scampton armourers had rapidly converted bits of Oriental rain forest into a new bar for the Sergeants’ Mess. :ok:

True? It is for me.

[langleybaston]

I think it was a submarine steering auxiliary motor, Vickers 4 cylinder.

[henry crun]

I have read that the bomb was spun up not less than 10 minutes prior to anticipated drop time.

Several pilots commented on the severe vibration when it was spinning at 500rpm; one said it so bad he could hardly read the instrument panel.

[ninja-lewis]

I think it was a submarine steering auxiliary motor, Vickers 4 cylinder.

From dambusters.org.uk (http://www.dambusters.org.uk/Bomb.html):

Once loaded and fitted in place the mine was initially intended to be spun by a Ford V8 engine but this was not implemented, Instead the hydraulic supply normally used for the mid-upper turret [removed of course on the Type 464 provisioning aircraft] was used to power a Vickers "Janny" hydraulic motor [originally believed to have been designed, for the steering gear of submarines] the speed of rotation being controlled by the W/Op who monitored a rev counter and controlled the hydraulic pressure via a control valve to a gearbox and pulley which drove a rubber belt and spun the bomb via a pulley. When the bomb was to be released two spring loaded arms which held it in place were allowed to flip outwards under spring pressure allowing the mine to drop

[Prawn2king4]

One of the actual trial bombs is displayed at Abbotsbury Gardens and Swannery (strange place to do so, perhaps), in Dorset.

[Trim Stab]

In terms of telling the story, not as good as 1954, I thought, and with too much pretending-not-to-know-things.


Nah... What really happened is here:

YouTube - Dambusters

[forget]

ninja lewis. It's Vickers Jassey - not Janny.

One of the actual trial bombs is displayed Just as well it wasn't used for real. Obviously a dud. :rolleyes:

Trim Stab. I'd forgotten how funny that was. Genius.

[Wokkafans]

Or the Hollywood remake a la Star Wars/ U571 :ok:

YouTube - The Dambusters a la Star Wars

[The Old Fat One]

Excellent prog...especially when you consider the dross that passes for TV these days.

I loved the "hurry and wait" bit as they went for the live drop, with associated goatf**k over the unbalanced bomb. Most on here will have seen similar during their time in the mob.

If you've not read it I strongly recommend "Dambusters" by Max Arthur, Virgin Books 2009. A gripping series of eyewitness accounts, including people like the AA commander from one of the Moehne Dam towers. What comes over in this book is not just the incredible skill of the crews, but also what a ruthless bunch Gibson had turned them into. Many of the gunners took extra ammo as a low level run in and out of Germany was just too good a "shoot em up" opportunity to be missed.

Interesting to note that Scheer never understood why they did not come back and bomb the crap out of the repairs to finish the dams off. As it was the effect on industry was negligable, but the moral boost was immense.

[anotherthing]

One of the actual trial bombs is displayed at Abbotsbury Gardens and Swannery (strange place to do so, perhaps), in Dorset.
Didn't some of the early testing take place at Chesil Beach? Might be the link...

[Trogger]

Newark Air Museum has one of the Upkeep test piece bombs dropped at Reculver in 1943 on display.

[Pontius Navigator]

There is another at East Kirkby and part of one at the Petwood Hotel.

[Double Zero]

When I last visited Duxford a few years ago they had an Upkeep; maybe it's been moved then ?

[aviate1138]

The reason why the A26 was included is a mystery [other than an editor that doesn't have any interest in aeroplanes].

Vídeo en VIDEOS.es (http://www.videos.es/reproductor/--(TcoBw1Gb_Ik)

Painful to watch.....

The DC4 pilot was a law unto himself wasn't he? Flew at a height He decided was suitable. Released the bomb late and as a result the bomb hit the dam with far too much speed and his comment at the end said it all. I would like to have seen him do the drop at night with gunfire raking the aircraft.........

"We showed those Englishmen we can hit it with the first shot."

Big mouth Captain Arnie.........

Biased because my Father worked for Barnes Wallis and Vickers during WW2

[Windy Militant]

The High ball was indeed spherical been done here http://www.pprune.org/aviation-history-nostalgia/370062-highball-tested-land.html

Anyone got a link to the movie mentioned in the last post.

[langleybaston]

spherical much better in theory because it has no "edge" to lead into water, and thus no chance of deviation from straight line. The levelling of wings is critical for an accurate run of a dustbin shape.

[LowObservable]

This is the only place where you will hear in one thread the word "soliflucation" and discussion of Ms York's uniform-shirt-and-stockings scene in BoB.

[BEagle]

'soliflucation' - good Scrabble word that!

Meanwhile, I give you:

http://i14.photobucket.com/albums/a341/nw969/SYork03.jpg

:ok:

[adr]

This is the only place where you will hear in one thread the word "soliflucation" and discussion of Ms York's uniform-shirt-and-stockings scene in BoB. -- LO
Not just in combination, either. Believe it or not, it's also the only discussion thread where I've encountered the word solifluction.

adr

[Trogger]

The reason why the A26 was included is a mystery [other than an editor that doesn't have any interest in aeroplanes].


Maybe to make the point that dropping bouncing bombs from too low can be catastrophic - just warning that doing so may result in getting your tail feathers a bit damp might not be enough (as evidenced by the DC-4 suffering a bit of splashback on one run)...

[Pontius Navigator]

The reason why the A26 was included is a mystery [other than an editor that doesn't have any interest in aeroplanes].

The A26 footage showed better than any verbal arguement that speed and height were critical to safe delivery. Interestingly the DC4 was below the critical height; one wonders if they showed the bush pilot that earlier film?

Perhaps not as he might have chickened out.

[Charlie Time]

The pilot was simply dangerous and placed the whole trial at risk. Interesting programme that highlighted why properly conducted trials have the safety hurdles in them that they do. Cockpit gradient too........I reckon the guy with 37,000 hours could have flown them both into the lake and the co-pilot would have kept quiet.

[Tourist]

Charlie

"Interesting programme that highlighted why properly conducted trials have the safety hurdles in them that they do."

Interesting point, though you should note that the original trials had none of these safety hurdles either, but the programme was a spectacular success.

Misguided though he may have been, the canadian pilot had very good handling skills.

[langleybaston]

Charlie Time, totally agree ...... a terrifying old boy, and a meek lad, cringe-making.

Give me Ms York

NOW!

[The Old Fat One]

Why is so many "educated" people don't understand that the media (TV, newspapers, whatever) show you want they want you to see. How do you think a program about large trucks and even larger truckers driving up and down a very boring, very cold road gets on prime time TV?

Answer, clever editing and dramatic music.

Same deal for the bouncing bomb program...interesting though it was, it is the job of the editor to spice it up for the larger audience, most of whom haven't a scoopies about the safety regimes for trials flying.

Give the guy a break...he probably spent days going over the safety procedures and parameters...wouldn't have made for great TV to show all of that though would it.

PS At the risk of treading on my own point...

Re the release point and the hard impact. Yep spotted that.. I wonder if the boffin briefed effectively. His comms skills did not appear to be all that.

[Tankertrashnav]

Give me Ms York

NOW!


Unfortunately you're about 4 months too late Langleybaston.:(

I should think most FO's would be a bit meek with the knowledge that the guy on their left hand had notched up the equivalent of over 4 years in the air! Yes he cut the odd corner, but he's certainly disproved the old adage about there being no old and bold pilots.

[MightyGem]

Not in suspenders, but in the shower:

http://www.youtube.com/watch?v=XrEc8ZiMyVc&feature=related

[MightyGem]

I've no idea why it shows twice. :confused:

[adr]

I've no idea why it shows twice.
Skilful editing? :E

I'll get me coat.

adr

[FTE Pruner]

Interesting point, though you should note that the original trials had none of these safety hurdles either, but the programme was a spectacular success.


I am not sure that is the point. Especially when you consider the video shown of aircraft crashing during the (admittedly post-war) testing.

Even if they did do safety assessments (which clearly wouldn't be shown on TV since they are generally tedious) I doubt the crew had sufficient specialist training to allow them do it correctly (evident from their actions during the testing).

Decisions like spinning up the bomb to full speed for the very next drop after a stores release hang-up (which could have ended in disaster) showed that the team were time pressure driven, on what was hardly a UOR!

However good the pilot was at flying, by deviating from the release parameters he exposed himself and his crew to unknown risk and also meant that the required data was not gathered!

If I were Dr Hunt, I would have been mightily annoyed that he ruined the only permitted opportunity to achieve the desired test point by making an uneducated decision.

That said, it was a good programme.

[LookingNorth]

Fascinating viewing but that pilot's judgment was appalling. If it had been a real bomb he and his crew would be dead (on the real raid one store hit a dam in similar circumstances and went off immediately, taking out the Lanc that had released it); as it was, the splash on the live drop alone must have come pretty close to taking his tail off.

[anotherthing]

If it had been a real bomb he and his crew would be dead
Irrespective of comments on judgement it wasn't a real bomb and was never going to be... complete non statement above :ugh:

[Pontius Navigator]

While wikipedia etc state that a bomb contains a destructive substance and is designed to explode, the 'store' dropped from the DC4 was by modern usage a BOMB.

A 1000lb Inert Bomb, with no explosive, is still a bomb. Low altitude releases can result in bounce and the splash can down an aircraft, both shown in this programme.

Regardless of whether it was a replica explosive bomb or this scaled replica store it was still capable of downing the DC4.

Had the release mechanism of the rotating store failed is some manner it could have been catastrophic.

[MAINJAFAD]

Fascinating viewing but that pilot's judgment was appalling. If it had been a real bomb he and his crew would be dead (on the real raid one store hit a dam in similar circumstances and went off immediately, taking out the Lanc that had released it); as it was, the splash on the live drop alone must have come pretty close to taking his tail off.

The Lanc that dropped the Upkeep that exploded on impact with the Eder Dam (AJ-Z, flown by Sdr Ldr Maudslay) was damaged, not destroyed. Though the damage mot likely resulted in the aircraft having to limp home as far as the German/Dutch boarder, where it was shot down by light flak. In fact I do recall reading somewhere that Maudslay was flying one of the aircraft in footage of the two Lancasters being hit by the water splash from the released Upkeep when senior 617 crews practiced with the weapon a couple of days before the raid.

[Ewan Whosearmy]

Next time Dr. Hunt asks to read 60 year-old documents, can someone else turn the pages for him?

Forget about the cavalier DC-4 pilot, I was more surprised to see Hunt flicking through Wallis' original paperwork as though he were leafing through the Sunday supplements - not a jot of care for their preservation. :ugh:

[Halton Brat]

Clearly, the reason that this programme was made in Canada is that the Campaign Against Aviation (CAA) in UK would have had a field day with this one. The requisite rain-forest volume of paperwork to be submitted would have joined Michael (Ryanair) O'Leary's ideas for stand-up seats & pay toilets.

BTW, on the subject of Ryanair, if you want to see a real rib-tickler, check out youtube 'fascinating aida cheap flights'. A real tonic!

[Moldiold2]

Anyone kow what happened to the Lancs modified to carry the bouncing bomb. Were they returned to standard configuration or kept in case they were required for further missions?

[jamesdevice]

"Anyone kow what happened to the Lancs modified to carry the bouncing bomb. Were they returned to standard configuration or kept in case they were required for further missions?"

According to the book "The Dambusters" the ones that survived the raid were rapidly returned to conventional configuration as they were desperately required for Bomber Commands saturation raids on Germany
This came to be a problem later when 617 were tasked to sink Tirpitz in a Nowegian fjord. The Upkeep bombs would have been ideal for hopping over the anti-torpedo nets. Instead 617 had to use "Tallboy" earthquake bombs (another Barnes Wallis design - they must have loved these suicide missions with his designs)

I've read somewhere that toward the end of the war a squadron of similar spherical Highball-fitted Mosquitos were sent out to the far east to attack Japanese shipping, but the Yanks refused to have them around and sent them back. Anyone know more?

ah -edit, courtesy of Google
618 Squadron had the Highball Mozzies, but never got to use them in anger it seems

[Extg3]

Any body having probs reading Page 5 of this thread. Click on the link and get straight back to page 4?
Very strange. It said there was a page 5 but it wasn't visible. Posted this message brought page 5 up with this the only post. So ZFR.

[jamesdevice]

not now you've posted that....
must be an index problem, but looks like it cured itself

[XR219]

Contrary to what was said in the programme, according to Wikipedia (so it must be true :rolleyes:) the US trials of Highball were not post-war; the first A-26 was converted by Vickers in January 1945 and the tests were carried out over Choctawhatchee Bay near Eglin Field, Florida where the unfortunate aircraft, A-26C-25-DT 43-22644, crashed fatally on 28 April 1945, thus ending the programme.

[Pontius Navigator]

the first A-26 was converted by Vickers in January 1945 and the tests were carried out over Choctawhatchee Bay near Eglin Field, Florida where the unfortunate aircraft, A-26C-25-DT 43-22644, crashed fatally on 28 April 1945, thus ending the programme.

Looks as if they were anti-shipping trials then for the Pacific.

[jamesdevice]

so - the Americans couldn't make Highball work, so they refused to let 618 Squadronl- who DID make it work in training - outdo them?

[jamesdevice]

archive film of Highball and Upkeep

YouTube - Dam busters or bouncing bomb

[Pontius Navigator]

Nice find. Some of the A26s in there too. Liked the flight of 3 Mozzies, clearly what you would need against a warship. Wonder which ship that was.

[jamesdevice]

according to Wikdipaedia 618 Squadron practiced on two ships:
first the French battleship Courbet
after that was used in the "Mulberry" harbours they used HMS Malaya

Hopefully someone can ID one or the other

Location for both ships was Loch Striven

[November4]

What would the advantage have been by using the bouncing bomb over a torpedo when attacking shipping?

[pr00ne]

November4,

Avoids torpedo nets, booms and other such defences.

[jamesdevice]

it was to get past torpedo nets hung around ships while anchored
The main initial target was Tirpitz, laid up in Norway in a fjord
The idea was to bounce the bomb over the nets, then have it sink below the ship and hole it low down where the armour was thinner.
A torpedo would hit too high - on the thickest part of the armour plate

there is apparently a training video in the war archives of 618 Squadron bowling rubberised Highballs down a railway tunnel in Wales. Its mentioned several times on the internet and theres a thread somewhere on pprune from a chap who has seen it, but it seems not to have leaked onto the internet

[November4]

Thanks James and Pr00ne - wasn't that the original reason that bouncing bomb was designed to overcome, the belief that the dams were protected by torpedo nets?

[jamesdevice]

I believe so - but thats only from what I've read !

[IFPS man]

The film held by the RAFM of Mosquito trials of the dropping of "highball" into a railway tunnel mouth in Wales are most impressive. The aircraft were flown by "Shorty" Longbottom and Bob Handasyde during October 1943

[jamesdevice]

just found another clip (on a Russian website!) showing 618 squadron practicing.
Includes twin-bomb releases - and the view of the impact from one of the ships

ЯП файлы - Dambuster Raid - VERY RARE test film including fatal American trial (http://www.yapfiles.ru/show/18047/fd4e3f9eae506d041c95ad15ebb31e96.flv.html)


50 minutes documentary about the dams raid - split as 5x10mins
http://www.youtube.com/watch?v=j_W6w2c9OQA&list=PL03F92064C31ABE1F
(http://www.yapfiles.ru/static/play.swf?st=vMDAwMTgwNDctfd4e])

[Green Flash]

I'm sure some Highball trials were against a hulk in Loch Fyne. And the Germans had a rocket propelled :ooh: 'Highball' called Kurt YouTube - kurt bomb

[Pontius Navigator]

The torpedo would of course have been caught by torpedo nets but would not have necessarily hit too high against the armoured belt. It could be set to run at an appropriate depth and even explode underneath the target.

The 18 inch torpedo Mark XII, an 18-inch-diameter (460 mm) model weighedg 1,548 pounds (702 kg) with an explosive charge of 388 pounds (176 kg) of trinitrotoluene (TNT).

The Upkeep on the other hand was and its overall weight was 1,280 pounds (581 kg), of which 600 pounds (272 kg) was Torpex.

The power to weight was clearly better. The bomb speed in the bounce compared with the speed of the torpedo in water would also be considerably greater which meant it could also have had a greater degree of success against a target underway.

The torpedo could also have directional problems whereas the highball, if launched in the right direction would probably have been more accurate.

[jamesdevice]

Interesting, thanks for that correction
Since my last post I've found a couple of online anecdotes to the effect that the dummy Highballs used against Malaya were actually able to punch a hole through her armour simply due to force of impact and resulted in her taking water and listing considerably.
Can't have been a happy experience for the ships crew (even if she was on reserve / skeleton manned)

[henry crun]

November4: My reading is the bouncing over the torpedo nets was incidental to the reason for the bomb.

To work as Barnes Wallis calculated, the bomb had to explode at the right depth while in contact with the dam, an accuracy conventional bombing could not hope to achieve.

The backspin caused the bomb to bounce, and at the end of its run, to roll down in contact with the face of the dam, which was why it was so important for it to be released at exactly the right range and height.