questions for Beaufort Boffins

[elger]

Hi all,

 

A while ago the forum was very helpful in getting some information regarding the size of aircraft launched mines

 

I've just started work on the ICM Beaufort and I'm planning to convert the supplied torpedo into a mine (the diameter will be slightly too big) but I was wondering if the mine would be suspended by the same mechanism as a torpedo (since they were similar in size, especially the diameter) - or if there was a different suspension / cradle system for the mine all together.

 

Any help would be greatly appreciated!

[elger]

Bumping this thread on the off chance someone who knows more missed the message before - and a few followup question about Beaufort configurations: I'm going to be building AW207 BX-H of 86 Squadron. The aircraft was lost in November 1941. It is my understanding this would have been in one of the last Mk 1 production batches. What would this mean for the aircraft's configuration? Might it have had the half round extensions on the rear of the flaps or the straight wings? Any thoughts on the presence or absence of the beam guns?

 

 

[Geoffrey Sinclair]

Not sure I can help that much.  AW207 was taken on charge in May 1941, 18 MU on 1 June, 86 squadron on 20 June, lost on a mine laying mission to the Freise Gat 24 November 1941.  Shot down by flak.

 

It was amongst the last of the initial mark I production, mark II started in September 1941, mark I production resumed in February 1942.  The beam guns began being fitted in May 1940, a field modification, The semi circular plates behind the nacelles began to be fitted in mid 1941, just in time to discover the larger diameter Wasps in the mark II did not need them.  The plates were retrofitted to earlier mark I production.

 

As the Beaufort is known as a torpedo bomber there do not seem to be any published references describing the mine carrying arrangement.  The mines came in at about 1,500 pounds, 9 feet long, slightly smaller diameter than the torpedoes which were 16 feet 3 inches long, 1,548 pounds (mark XII) and 17 feet 2.75 inches long, 1,801 pounds (mark XV), I expect the mine could be carried in the bomb bay, unlike the torpedo.

[Tomas Enerdal]

In the recent Beaufort reference; The Bristol Beaufort, A Technical Guide (Valiant wings), there is a diagram on p.53 showing various Ordnance alternatives.

One of the is the 1500 lb. mine.

The diagram is not that detailed, but the mine in itself seems to be both too long and too large diameter to be able to be carried fully inside the bomb bay. I therefore suspect a carrying arrangement similar or identical to the torpedo, semi-recessed with open wells fore and aft of the bomb bay itself. There are nice diagrams showing the torpedo arrangement in the book as well. Highly recommended for Beaufort builders.

The mine itself is available in 1/48 from Belcher Bits, in the set BB-11, see here.

[EwenS]

4 hours ago, Tomas Enerdal said:

In the recent Beaufort reference; The Bristol Beaufort, A Technical Guide (Valiant wings), there is a diagram on p.53 showing various Ordnance alternatives.

One of the is the 1500 lb. mine.

The diagram is not that detailed, but the mine in itself seems to be both too long and too large diameter to be able to be carried fully inside the bomb bay. I therefore suspect a carrying arrangement similar or identical to the torpedo, semi-recessed with open wells fore and aft of the bomb bay itself. There are nice diagrams showing the torpedo arrangement in the book as well. Highly recommended for Beaufort builders.

The mine itself is available in 1/48 from Belcher Bits, in the set BB-11, see here.

You will find some scanty details here

http://www.navweaps.com/Weapons/WAMBR_Mines.php

https://www.lancaster-ed559.co.uk/raf-gardening-operations-during-the-second-world-war.html

https://tailendcharlietedchurch.wordpress.com/operations/gardening-mine-laying/

Designed to be dropped from the torpedo gear or later the 4,000lb Cookie bomb gear.

[Seahawk]

On 1/15/2023 at 11:00 AM, elger said:

I've just started work on the ICM Beaufort and I'm planning to convert the supplied torpedo into a mine (the diameter will be slightly too big) but I was wondering if the mine would be suspended by the same mechanism as a torpedo (since they were similar in size, especially the diameter) - or if there was a different suspension / cradle system for the mine all together.

 

• The first source cited by @EwenS above states that the A Mk.I 1500 lb mine was originally designed to be fitted to carriers for the 18" torpedo. 
• All marks of the 1500lb mine were essentially identical externally to the original Mk.I (same source), so much so that, by the time the Mk.IV mine was introduced in 1941, "it was universally known as the 1,500 lb A Mk I-IV" (from now on all info from source below).
• Albacore and Swordfish aircraft laid mines in the Mediterranean and off the coast of the Low Countries.  [Presumably they were dropped from the crutches for the 18" torpedo.  (My comment)]
• The 1,500 lb A Mk I-IV's casing  was of cylindrical steel.  It was 18" in diameter and 120" long including the parachute pack and nose fairing (discarded on surface).  [NB 120" differs from the figure quoted elsewhere in this and the previous thread.  Your choice which to go with.]
• The 1,500 lb A Mk I-IV and its smaller relative the 1,000lb A Mk.V were the two air-delivered mines predominantly used during the war years.
• The 18" Mark XII torpedo in use from 1940 was "approximately 204" (17 feet) long when fully assembled".   Its weight, with an impact pistol and 545lb of Torpex, was 1801 lb.

So it would seem to me that the Beaufort would be able to carry a mine that was lighter, shorter and of the same/similar diameter as the torpedo it was designed to carry.

 

Source for all info not from Ewen's source is Bombs Gone: The Development of British Air-Dropped Weapons From 1912 to the Present Day by Wg Cdr John A MacBean and Major Arthur S Hogben (PSL, 1990).

[tempestfan]

1 hour ago, Seahawk said:

 

• The 1,500 lb A Mk I-IV's casing  was of cylindrical steel.  It was 18" in diameter and 120" long including the parachute pack and nose fairing (discarded on surface).  [NB 120" differs from the figure quoted elsewhere in this and the previous thread.  Your choice which to go with.

The difference is just the diameter of an LP and may possibly be explained by the quoted nose fairing, in particular, or something like 6"/6" for the nose and tail fittings?

[Graham Boak]

6 hours ago, Seahawk said:

 

So it would seem to me that the Beaufort would be able to carry a mine that was lighter, shorter and of the same/similar diameter as the torpedo it was designed to carry.

 

Agreed, but it isn't quite that simple.  The torpedo had to be carried semi-externally because of its length, including the Monoplane Air Tail (which was too wide for the bombbay anyway).  It does seem likely that the mine was carried on the same Heavy Store Carrier as the torpedo (I don't know of any other, perhaps someone does) and so would almost certainly be carried semi-externally too.  There is after all no doubt that the Beaufort could carry the mine, the question is how?

 

Note that here again we find stores designed prewar with a maximum width, for which the bomb cells of all British bombers were designed - except the Manchester, fortunately for its successor and the later designs of British weapons.

[europapete]

Also don't forget Aerocraft Models has released a cowling correction set for the ICM kit

[elger]

a little off topic but yes that does look good and I've ordered a set a few days ago

[Tomas Enerdal]

(Slightly repeating myself)

The Beaufort diagram I mentioned in post above, seems to be taken from an official publication (the caption states Crown Copyright).

The mine itself is of 18" dia, same as the torpedo. It has been stated/mentioned (EwenS above) that is was designed to be dropped from "the torpedo gear".

The mine is too long for the Beaufort bomb bay proper. I suppose it was centered under the a/c in a way similar to a torpedo, for CoG reasons. It then needed to use the recess wells/bays fore and aft of the bomb bay, again in a way similar or identical to the torpedo. (All supported/indicated by the diagram)