Surviving Belfast Truss Hangars

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16 years 7 months

Posts: 10,647

Thanks Baz, I was hoping it was a case that the old Coupled GS just had a reclad pitched roof, with the old internal structure still in place. I'm sure it was a Belfast Truss GS shed.

St Athan has had its Ds reclad with completely wrong roof shape, luckily the original structure is still in place underneath.

Member for

16 years 2 months

Posts: 2,841

Hooton's hangars

Hooton Park, technically has (had?) six as they are double-bay hangars.
Unfortunately there are only three (one double) and a half (one half of a double) anything like habitable.
Ever since they were "saved" from the General Motors developers ten years ago much hot air has been expended in saving these hangars but, as I speak, nothing at all has been done - excepting a little maintenance here and there and much collapsing has taken place.
Politics and vested interests have taken precedence where action should have occurred. The ball has passed between HLF, English Heritage, Ellesmere Port & Neston Borough Council and the Hooton park Trust, with, I am sure, more than a little input from GM here and there.
We were reassured that, over this time period, the hangars were in the right hands and I remember one grand statement of "there are no clouds over Hooton Park" being voiced. Result? Jack s**t.
Presently, the "big" men (who assured us they had all the answers) have departed and the HPT struggle on. It's held together by the volunteers and groups and the last vestiges of the HPT committee.
Sorry, but I've felt it necessary to give vent to my feelings about the Hooton Park site and the way it's been "managed" and let-down over the last 10 years. Us, the volunteers, were assured it was safe and in the right hands time and time again and that they knew better - It was 99% hot air.
These are historic hangars (they'll have stood for a hundred years in 8 year's time) and I have no faith in any of the so-called grant-funding bodies to help us save them - they are wracked by politics and favouritism and lack the balls to tell us the truth - though I think that latter comment sums up many a management committee.
Ten years ago there were lots of Belfast Truss hangars. There are a lot less now, and that number is reducing rapidly still.
Sealand (the satellite to Hooton park) 's Belfast Truss hangars have been completely renovated and are used for commercial purposes now, so at least they will survive for the forseeable future.

Anon.

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24 years 2 months

Posts: 249

Filton

Further to my earlier post, here are a couple of photos of the Belfast-trussed triple-span hangar at Filton. The first is a Citation inside the centre bay, which is divided down the middle. The other side of the centre bay is used by RRHT and Robs Lamplough for various Spitfires etc. I have lightened the photo to highlight the trusses.

The second photo is Spitfire G-BKMI outside, with Mustang G-BIXL inside. It shows two of the three spans. Both photos were taken about 8 or 9 years ago.

There are two hangars with Grade II listed status at Filton; this one and an earlier 1916/17-built 1913-designed corrugated iron-clad side-opening hangar, which is I believe is quite rare.

Here is a description taken from the internet...

Triple Hangar at ST 60 806, Filton Airfield

Group of four paired aircraft hangars in line. 1918 by the War office’s Directorate of Fortifications and Works to drawing no. 417/17. Walls, buttresses, central piers and door ‘pylons’ in brick, curtain walls half-brick thickness in cheaper bricks, softwood ‘Belfast’ roof trusses, corrugated steel door cladding and later profiled steel roofing.

PLAN: a triple-span shed, each shed divided by a central row of brick piers; on each of the longer sides is a low single-storey set of stores or offices.

EXTERIOR: Triple segmental gables presented to E and W elevations. The general design of all the sheds is similar, with minor differences in the scope of the attached out-buildings. A series of raking buttresses to the side walls, which have brick workshop annexes with steel casement windows, Brick ‘pylons’ outside of the outer bays, into which slid the doors, are in red brick, with three sets of paired piers carrying thin brick stiffening diaphragms with straight top but segmental lower edge – similar to the internal construction.

INTERIOR: Hangars divided by central row of paired brick columns; these carry a longitudinal thin brick stiffening diaphragm in brick on a segmental arch, are 2 bricks square, with a clear gap, and the outer faces carry a concrete spreader on brick corbelled in 3 courses to carry a strut in 3 small scantling timbers spliced into the doubled bottom chord of Belfast trusses. These trusses, commonly used from 1916 for aircraft hangars, have their bearing ends plated in diagonal boarding to the point where the strut is taken in, then a close-set diagonal grid of small struts. The double upper chord, in a flat segment, carried close-set purlins, and the lined profile roof sheeting. There is a vertical X-bracing between bays, and horizontal bracing in the bays adjoining the main doors.

HISTORY: .... The buildings, which survive as the most complete on any of these types of sites in existence (numbering 27) in November 1918, were retained for use by the Bristol Aeroplane Company after the war, and after 1929 became part of an operational fighter base. Following the disbanding of 501 (County of Gloucester) Squadron in 1957, the hangars reverted to use by the aircraft factory, now British Aerospace.

......

There were originally four of these on the airfield, only one survives.

Andy

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Member for

24 years 2 months

Posts: 2,835

Thanks for all your posts! I'm particularly interested in the coupled general service sheds. There seem to be a few left - sorry to hear that some have been demolished fairly recently. Are any in danger at the moment?

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16 years 6 months

Posts: 2,322

I am totaly out of my league here ! but the photo is Duxford, last year, please ignore the subject, but is this therefore a belfast truss within a coupled general service shed ??? Wow what workmanship !!!

Keith.

http://i261.photobucket.com/albums/ii58/keithnewsome/duxford/DSC_0173.jpg

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16 years 7 months

Posts: 10,647

is this therefore a belfast truss within a coupled general service shed ??? Wow what workmanship !!!

Nice pics Filtonflyer and Keith, yes that is a 1917 Coupled (referring to the double or triple shed layout) General Service Shed, with a Belfast Truss roof structure. The Truss itself is a thing of industrial beauty, as is the rest of the Hangar with its distinctive brickwork etc.
Considering these were builf for the RFC in 1917, we have certainly got our moneys' worth out of them!

IMO it would be fair to say that most of these Coupled General Service Sheds had the Belfast Truss roof structure.

As for wether their future is safe, well Fords' have been demolished in recent times, and Hootons' don't appear to be in a happy state. Nothing is guaranteed, but Hendons', Henlows' and Duxfords' seem the safest. Filton, Sealand, and Boscombe seem cherished aswel.

Member for

16 years 3 months

Posts: 1,813

Those at Sealand have undergone a major renovation within the last three to four years: at some considerable expense, no doubt. Have not been past recently to see who has moved in.

It is pity that those at Hooton have not undergone the same sort of renovation.

Planemike...........

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17 years 6 months

Posts: 1,433

What is RAF Henlow actually used for? The hangar shot is amazing.

RAF Henlow is still an active RAF base, containing the School of Medicine and various other ground-based operations.

The all-grass airfield and one side of one of the double-bay Belfast-truss hangars is used by the Grob Tutors of the RAF Volunteer Gliding School. The other side of the hangar contains a number of aircraft operated by private owners, many RAF personnel. The forgiving grass airfield means that there is a higher-than-average proportion of vintage types, particularly DH Moths!

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20 years

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Slight thread drift but is the Belfast Truss design philosophy the same as the geodetic construction on the Wellington? It certainly looks similar.

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18 years 3 months

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At Old Sarum five Belfast Truss hangars exist, two pairs and a single. One pair is used for aircraft, the single by a none aviation business and the last pair are up for lease, see here (would be nice to see them used for what they were built for).
http://www.myddeltonmajor.co.uk/commercial/documents/Hangar2OldSarumAirfieldParticulars_001.pdf

Richard

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17 years 10 months

Posts: 105

I recently attended for a job interview at MSI Defence Systems Ltd in Norwich,their premises are what I know as the 'old Boulton and Paul factory' which is where Mousehold Aerodrome was,they still have to 2 of the old buildings with Belfast Truss roofs.

Member for

20 years 6 months

Posts: 8,195

Fascinating. If I unerstand correctly, 'Belfast Truss' is a technical term for that kind of wooden lattice (to give a curved roof?).

Slight thread drift but is the Belfast Truss design philosophy the same as the geodetic construction on the Wellington? It certainly looks similar.

I'm no engineer, but no. The truss in the Belfast Truss case created a beam structure, with the roof loads spread to run vertically down the brick piers. The geodetic design by Barnes Wallis is based on taking loads around a sphere - geodetics being a geographic term, borrowed by Wallis, from the shape of the planet, and adopted by him to take loads around a semi-monocoque structure. There is a load path eliment in common, but otherwise different.

Of course, I may be wrong!

Member for

16 years 7 months

Posts: 10,647

Fascinating. If I unerstand correctly, 'Belfast Truss' is a technical term for that kind of wooden lattice (to give a curved roof?).

It was a system of roof truss design pioneered by an Irish company in the late 1800s and I believe was licenced to them. Thus that 'trelis style' is known as Belfast Truss in a similar way that vacumn cleaners tend to be called Hoovers.

I'm not sure that the BT nescesarily gave the curved external finish (though definately a feature of it), as the other General Service Sheds with 'ordinary' trusses have the same roofline.

I would agree with your geodetics comparison, both lightweight load bearing structures, but working in different ways.

These magnificent GS Sheds and Belfast Trusses are a British design classic IMO.

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18 years 3 months

Posts: 92

There's also a couple of these hangars at the old WW1 airfield / WW2 Avro factory at Bracebridge Heath just up the A15 from Waddington. One has been refurbished, the remaining other looks a bit tatty but both appear to be still in use. I'm sure there were more there in recent years.

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16 years 7 months

Posts: 10,647

From Paul Francis' excellent Airfield Architecture book I have lifted this info, there is much more about the design itself, but I am short on time.

'An advertisement for McTear & Co Ltd published in the Dublin Builder for 1 October 1866 is the earliest known reference to the Belfast truss roof.'

'Mc Tear ceased trading in 1903 and the construction of the truss was continued in Belfast by a number of companies. One of these, D.Anderson & Co. Ltd, a trader in felt from 1895 and a builder of roofs from 1877, actively marketed the Anderson Belfast truss ROK Roofing in the early 1900s. By 1915 the company was advertising in 'Flight'.

This book also suggests I'm wrong in my previous assumption about the differing roof curves, though they are very similar to look at externally,

'The outside appearance of the Belfast roof appears to be a perfectly smooth curve, whereas the curve of the bow-strung truss roof is roughly polygonal' that would be similar to the curved, but definatly angled appearence of a 20p or 50p coin.

The ROK name was also applied to the roof sheeting of diagonally placed tongue & groove board, and felt & bituman covering

Member for

18 years 7 months

Posts: 382

The Belfast Truss is a structurally efficient way of spanning large distances whilst using very common (read cheap) elements.

The large number and their relatively short length means a large potential supply of basic material.

For the bow string truss each individual element is carrying a greater percentage of the load (either in tension or compression) and hence needs a higher specification.. (for which read higher quality and hence cost).

What makes them so interesting is that it was the material cost that drove this design, not the labour cost required to assemble the much larger number of elements to create each truss. In contemporary building the higher priced material which demands lower labour cost would be the one selected every time as labour is now the driving element in such construction.

The upper element is curved as it approximates best the shortest path between two individual cross brace...inagine the bow string as a greatly magnified Belfast...But the roof pitch that goes over the top of either is a choice... it could be pitched (more effective but more expensive roof) or curved... cheaper but has other performance issues to do with drainage.

The Duxford Hangers are pretty safe...especially as Duxford is now creating an 'buildings' based educational programme...

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20 years 9 months

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At Old Sarum five Belfast Truss hangars exist, two pairs and a single.

Good to see they are Grade 1 listed :)

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19 years 7 months

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I'll have to check my photos, but I think the surviving hangars from the RFC Canada hangar line at CFB Borden north of Toronto may have this type of roof construction. Will confirm later...

S.

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16 years 7 months

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Yes please Steve!

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24 years 2 months

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re

There's also a couple of these hangars at the old WW1 airfield / WW2 Avro factory at Bracebridge Heath just up the A15 from Waddington. One has been refurbished, the remaining other looks a bit tatty but both appear to be still in use. I'm sure there were more there in recent years.

your right, they knocked down a pair of very derelict ones a few years ago, and sadly have bricked up the windows of what looks to be a guardroom near the main road.