Seafire lb and llc Catapult Spools and Attachments

[roncl]

Does anyone have any drawings or pictures showing detail of the catapult spools that were used on the Seafire lb and llc?  Were there two spools or four?  Finally, does anyone have any drawings or illustrations showing how the Seafire was connected to the catapult system and where the cables and other items were attached to the aircraft?  

 

I gather the Seafire lll did not use a catapult. Can anyone confirm this?

 

Thanks in advance. 

 

Ron

[Graham Boak]

I believe that the rear mounting was just a spigot on each side aft of the wing (not sure exactly how this was managed given the fillet) whereas the front attachment was rather like a small castor (just not castoring).  This is based on the fittings for the Sea Hurricane.  There would be no cables attached to the aircraft itself, and the aircraft was attached to a trolley which was accelerated and the aircraft flew off at the end of the track. 

 

This was replaced by the US system late in the war (presumably because of the widespread use of US aircraft) where a two cables in a V shape were attached to a much smaller shuttle. and the aircraft did not have to be raised to a level attitude, speeding up matters considerably.  I'm not sure just where these cables were attached.  I was just reading Eric brown's Wings of the Navy, whee he refers to this on the first flight of the Mk.XV, 12th May 1944.  So the system was available then, in time for the use of the Mk.III on Fleet carriers with the BPF.  Whether it was so used I can't say, but I would imagine so.  It had mainly been used on the escort carriers until then (I think!).  I suspect that this may be the origin of the suggestion that the Seafire Mk. III did not use a catapult (or accelerator in RN terminology).   Brown makes no suggestion that it was lightened by the removal of the earlier equipment

Edited November 19, 2019 by Graham Boak
Removal of reference to Mk.Ib; better reference to use of later system.

[72modeler]

The first  short video shows how the shuttle was attached to the rear spigots on what I think is an an LF II. Hope it helps. If I come across anything better, I will re-post. The second also has some footage that you might find interesting. The third won't help answer your Seafire query, but does have some great Martlet, Albacore, Fulmar, and Swordfish footage! I can look through my Seafire references to see what I can find- I'm sure one of our resident FAA fanatics will be along shortly to take care of you.

Mike

 

https://www.youtube.com/watch?v=C3VrnWOJ7qw

 

https://www.youtube.com/watch?v=06kldAC7nus

 

https://www.youtube.com/watch?v=CfzQwAbz9F4

 

[roncl]

Thanks Graham and 72Modeler. I really appreciate the information. I have a better idea now, but still don’t quite fully understand how the catapult system worked on the Seafire. It sounds like the procedure for launching the Seafire changed during the war. I look forward to seeing any additional information that might be provided. Thanks again. 

[EwenS]

The British BH.III Accelerator (H for hydraulic, accelerator = catapult) was introduced in the early 1930s and, as you have seen in the short video, used an adjustable trolley to raise the aircraft into a flying position before it was boosted off. The aircraft sat on 4 arms. Two arms attached via spigots/catapult spools to the aft fuselage and another 2 around the trailing edge of the wing (the exact locations varied from aircraft type to type). When the catapult reached the end of its travel the trolley collapsed and the aircraft, having gained flying speed, flew off.

 

Turning to the Seafire, there are drawings and photos in Shacklady's "Spitfire The History" at pages 525, 539-541 and 556. Most Seafire plans don’t include them. Unfortunately my scanner is not working, but I'll do my best to describe them.

Catapult spools began to be fitted with the Seafire IIc, which were built as Seafires from the ground up. The Seafire Ib were conversions from Spitfire V so presumably the necessary fuselage reinforcement and fittings needed couldn’t be retrofitted. They continue to appear in photos of factory fresh MkIIIs and also on Mark XV & XVII which used the same basic fuselage.

 

On the Seafire the aft catapult spools were attached to Frame 16, just above the bottom longeron i.e just above the camouflage demarcation line between upper and lower surface colours and just aft of the fuselage roundel. They resembled large bolts sticking out of the fuselage from a reinforcement plate riveted to the fuselage. They are not easy to see in period photos (think Frankenstein!). Shacklady notes under the Seafire XV that these spools were detachable, which may explain why they are not visible as the Seafire seldom used the catapult, and they could therefore be removed safely so saving weight and drag. Being so far aft meant no interference with the wing structure at all. Below you will find links to pictures of Canadian Seafire XV. PR434 AA-J has a spool under the “J” and PR479 AA-B has a spool under the second “A”. You are looking for a little object sticking out from the fuselage side.

https://ww2aircraft.net/forum/threads/1-48-seafire-xv-post-war-warbirds.45035/

 

Even harder to see, let alone find pictures of, are the front catapult spools as they tend to be masked by wing, radiators, fuel tanks, bombs etc depending on the angle they are viewed from. They were attached to braced frames (resembling small "legs") protruding from the lower fuselage at Frame 9 (one frame forward of the rear spar attachment point) with the braces extending forward to Frame 8. Frame 9 is roughly in line with the mid-point of the fixed part of the windscreen. Again these seem to have been detachable.

 

This trolley launch method was clumsy and time consuming to use. In the early war period aircraft were generally light enough, and the numbers being flown off at any one time were relatively few, so not much use was made of it. US aircraft types, such as the Martlet, supplied under Lend-Lease had these spools fitted to ensure compatibility. As aircraft got heavier the RN developed RATOG for all types of carrier aircraft. But right to the end of the war and beyond it seems that the preference in the RN was for unassisted take-offs, certainly from larger carriers and with British types from the escort carriers. That said, there is evidence of trolley launches of Fireflies and Barracudas in the BPF until at least mid-1945 and probably immediately post-war (I’ve seen a phot of a Barracuda loaded onto the trolley for demonstration purposes dated Oct 1946).  I’m now struggling to remember seeing any tail down launches from British built carriers during the war.

 

In 1942 the US escort carriers started to arrive with US style accelerators (H-4) that were not compatible with the British trolley system as they used the tail-down launching method. So those catapults were not used when the carriers carried British aircraft, hence the development of RATOG. They were used with American aircraft types especially in the light winds of the Far East.

 

The RAE at Farnborough began tests with tail down launching of British aircraft in 1943. However the Seafire XV was not cleared for tail town launches until July 1945 (Eric Brown was flying the prototype MkXV in May 1944) and I don’t know if this was ever productionised or if the fittings were still prototypes. I can tell you that by 1947 the Mk47 had 2 hooks installed just behind the wing leading edge either side, very slightly inboard of the undercarriage to take the strop for tail down launching. By Korea in 1950 tail down catapult launches were regular practice with Sea Furies & Fireflies.

 

In relation to your specific question about the Seafire III not using the catapult, my answer would be that it was not the common practice to use it as the engine was sufficiently powerful and the airframe light enough that it could get safely off the deck with a drop tank or 500lb bomb of even an escort carrier without it. That allowed carriers to speed up their launch cycles. That was not something that changed until post-war.

 

I’ve had a look at MkXVII SX336 and MkIII PP972 which are flying today but I can’t see any trace of the catapult spools. The FAA Museum MkXVII SX137 seems to have mounting points where the aft spools would be fitted but no sign of any spools themselves.

 

I hope this helps.

[Grey Beema]

This help at all?

 

 

[Grey Beema]

3 hours ago, EwenS said:

 

In relation to your specific question about the Seafire III not using the catapult, my answer would be that it was not the common practice to use it as the engine was sufficiently powerful and the airframe light enough that it could get safely off the deck with a drop tank or 500lb bomb of even an escort carrier without it. That allowed carriers to speed up their launch cycles. That was not something that changed until post-war.

 

I understand the problem was sometimes less about getting them up and more about getting them down. During the Salerno landings due to a combination of factors; no wind, slow Escort Carriers and small carrier operating boxes, getting enough wind over the deck so that the relative speed to the carrier was safe for landing was not possible, which it why so many ended up in the barrier...

[roncl]

Ewen and Grey,

 

Thanks very much for the outstanding information!  Ewen, I really appreciate you taking the time to provide me with such a detailed explanation of how the catapult system worked for the Seafire.  That must have taken a fair bit of time.  You have certainly answered the questions I had about the catapult system that was used for the Seafire.  Grey, thank you very much for posting the picture showing the Seafire fuselage construction.  The detail is excellent, and provides great visual information to go with Ewen's excellent verbal description.  Thanks to everyone (Graham, 72modeler, Ewen and Grey) for taking the time to answer my questions and for providing such excellent information.  I certainly understand how the process worked now!

[Grey Beema]

No problem - that's what we are all here for..

[Blimpyboy]

On 11/20/2019 at 8:48 AM, Graham Boak said:

the front attachment was rather like a small castor (just not castoring).  This is based on the fittings for the Sea Hurricane.  There would be no cables attached to the aircraft itself, and the aircraft was attached to a trolley which was accelerated and the aircraft flew off at the end of the track

 

I've always been curious about the use of the term 'spool' to describe these fittings.

It makes some sense, to me, if there was a castoring or other rotating function to facilitate disengaging from the trolley attachments (if that's how the spools functioned).

Was there ever any kind of trolley-to-aircraft cabling associated with this mechanism?

Otherwise, is the term spool a bit of a misnomer, based on appearances (like some pipe spools)?

 

 

Bring back the good ol' bridle, I say.

 

Edited January 13, 2021 by Blimpyboy

[EwenS]

Probably because back in the day, before everything in the world of you youngsters went digital, it was in common usage for a device, cylindrical in shape, with a lip at each end which is what the device on the aircraft looked like. Commonly used term for example for a bobbin (look it up!) for winding thread or a reel for holding film.

https://www.merriam-webster.com/dictionary/spool

 

Just another part of our heritage.

[Blimpyboy]

I did wonder that - just like pipe spools...

 

In my day, we slung them airy-planes off the boat with the bridle!

And still had change to go to the talkies (moving pictures to you young-uns) afterwards.

 

 

Well, maybe not quite that old!

 

Edited January 13, 2021 by Blimpyboy

[Blimpyboy]

 

Perhaps only slightly off topic, but the only spools worth anything are on fishing gear...

 

 

 

 

Edited January 14, 2021 by Blimpyboy

[EwenS]

Ah but to me that has always been a reel!😉

 

 

 

 

[72modeler]

Is that a Sturgeon Mk 1 or a Spearfish?  

Mike

[EwenS]

4 hours ago, 72modeler said:

Is that a Sturgeon Mk 1 or a Spearfish?  

Mike

Well it is not a Swordish or an Albacore. Only one set of fins!

[fishplanebeer]

The fuselage diagram is on page 539 of Shacklady so if you have or can borrow a copy it's well worth it as it also has some good pics showing the forward mounted spools in place. In addition Warpaint No 72/Merlin Seafires has a good set of 72nd scale plans for all versions showing all the various mods that were made.

 

Regards

Colin.

[Blimpyboy]

13 hours ago, 72modeler said:

Is that a Sturgeon Mk 1

 

9 hours ago, EwenS said:

it is not a Swordish or an Albacore.