Dambusters: Building the Bouncing Bomb
 

Tonight 2000hrs Channel 4:

Some video preview is online here -
Dambusters documentary recreates the science behind WW2's most audacious bombing raid | Mail Online

Looks to be an interesting programme...

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.

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)

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

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

Can This Be A Record?

Beagle - you just spoiled it!

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

A Bridge Too Far?

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

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

:)

Ah yes......


:ok:

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

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

U J
 

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.

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

You guys do it lying down? :confused:

Is that the Moehnesee behind her?:E

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

Susannah really was so gorgeous:


Those eyes hinted at such....fun!

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

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

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.

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

Do you take water with your viagra? :p


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

I'm much relieved to hear that!

Back to the Program
 

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)

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!

BEagle, get Mrs B to repair the pockets then.

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:

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

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

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!

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:

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.

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.

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?

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?

New Dambusters film
 

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]
:)

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

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.

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.