Why are hangars so high?

Question

Or, to be more precise why was the Type-C hangar so tall? Built in the 1930s across many airfields in the UK, it was built with a higher roof (11 m) than any contemporary aircraft. (higher even than the tail of the worlds largest aircraft the Tupolev ANT-20)

Even by the end of WW2 it was still higher than any UK aircraft, even the American flying fortress could fit in (height wise)

So, why so tall? were they expecting future aircraft to be much higher? Was it also intended to house blimps? or is there some other reason?

Answer 1

Gantry cranes. Buildings where people work on big machines usually have high ceilings, and often those ceilings leave space for gantry cranes. The cranes may have been removed or never installed.

This is not specific to aircraft.

Spacecraft:

Trains:

Submarines:

Turbines:

It would be quite hard to perform an engine change on a Handley Page H.P.54 Harrow (1936) without a big crane. Engines needed more frequent maintenance back then.

Answer 2

11 meters isn't tall. You should see a modern hangar...

Note how much headroom there is between the tip of the tail and anything on the roof that could potentially damage it.

The aircraft doesn't always sit perfectly level on its gear, the roof can sag, the floor can be uneven, there's lights hanging from the roof, and you have people working on the aircraft. Even more headroom was desired in hangar design, because aircraft were getting larger every year, and it wasn't easy to predict this growth.

Most British bombers kept using twin tails, which result in a lower total height than a single tail. Yet, there were single-tail proposals, and had one won, the plane would've been taller. Twin tails stayed, so they lowered the roof eventually. Large single-tailed American bombers, like the B-29 and B-32, would've been too tall for the Type C hangar. So would the Britain' own Short Sunderland.

So, headroom was provided both for practicality and for future aircraft which might have been taller than they turned out to be.

Answer 3

Well the Lancaster bomber was almost 7 meters from the ground, which doesn't leave huge amounts of clearance if you need to jack up the aircraft. Remember, these are maintenance hangars. Notice how every car workshop you go to has tall ceilings too!

The ANT 20 you mention was 10.6 meters - bearing in mind the height of the hangar isn't the same as the internal usable space, or indeed the door opening height, it seems it would be unlikely to fit at all, let alone be an excessive design

Your own link then goes on to say that as designs did normalise and we reached what seemed to be the reasonable limits for bomber design, that the hangar design changed and the roof dropped.

Answer 4

Other design considerations for any industrial building, not just aircraft storage, maintenance or manufacturing, are lighting, ventilation, separation of incompatible processes & fire control.

Higher ceilings facilitate better indirect, shadow-free lighting from natural sources or extremely bright point sources, out of eyelines.

Airspace over work areas improves natural circulation of fresh air & dispersal of paint, solvent & cleaning vapours, hot work gases & smoke. It promotes a safer & less noisy work environment.

You do not want the carpentry power tools creating sawdust clouds rolling along the ceiling into the welding bay. You don't want the machinists having to go outside to turn around a 20 foot length of stock to avoid the spray painters because they can't end-over-end it.

Fire can spread faster & be harder to isolate & fight effectively in a constricted space. It is helpful to be able to use firehoses from a safe(r) distance while remaining inside the structure. The aircraft of the first half century of aviation were outrageously flammable. High ceilings ameliorated this while delaying smoke saturation to some degree.

Answer 5

Hangers were originally enormously high, because they were first built to accommodate airships. Dumping an airship on the floor would wreck it: they did not have undercarriage (at least, not for the bow and stern), they were up to 900 feet long, all the important stuff was along the keel for stability, and the whole framework was designed to be in tension, not compression. The main circular frames were designed like spoked bicycle wheels.

The building are called hangars literally because the airship was hung from the roof, before the hydrogen was vented for safety, and maintenance could begin.

Answer 6

They must be that high because its an C shaped construction, all C shaped halls are like this, the benefit is a roof that dont need supporting down to the ground inside the building, this gives you a fully open and large areal with no obstructions... The same goes for thoose who wonders why they C shape a tunnel roof. The fysics behind the C shape are well explained.