Simviation Forum - Brabazon specifics

Mar 21^st, 2008 at 10:53am

chornedsnorkack Offline
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The Brabazon commitee discovered that a passenger needs 6 to 8 cubic m cabin volme per head for comfort.

At first, they planned a plane with fuselage 760 cm across. Then they found they did not need to carry so many passengers, and built the Brabazon with fuselage width of 510 cm.

Boeing 767 is 503 cm wide, so similar to Brabazon.

The 55 m length of Brabazon is close to the length of 767-300.

It is just that 767-300 misses the 70 m wingspan of Brabazon. As well as the 500 square metre wing area. On the other hand, the take-off weight of Brabazon, 130 tons, is lighter than that of 767.

In view of the Brabazon low wing loading, what are its approach speed and landing runway requirements?

How strong are those four engines of Brabazon, and how much runway does Brabazon need to accelerate to take off?

The cabin volume of 767-300 is said to be about 480 cubic metres. So suited for 60 to 80 passengers. 767-200 has about 420 cubic metres cabin volume, suitable for 50 to 70 passengers.

Silverjet has too many passengers (102) on 767-200. However, Privatair does have a 767-300ER fitted for 50 passengers.

The Privatair 767-300 has 12 seats in front - 4 rows at 3 abreast - and 38 seats in the rear, at 4 abreast. Plus a bar table with 6 seats.

Google has a 50 seat 767-200. Which includes seats for many retainers and employees, as well as bedrooms of both founders.

What was the interior of a Bristol Brabazon like?

http://www.aviationarchive.org.uk/stories/getobjectstory.php?rnum=G1286&enum=GE1...

is illegible, but the upper right image shows 3-seat blocks. So, it seems that Brabazon was a single-aisle 6 abreast plane?

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Reply #1 - Mar 21^st, 2008 at 11:21am

C Offline
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Quote:

What was the interior of a Bristol Brabazon like?

I think asking that question is on a par with looking at A380 cabin mock ups from 6 or 7 years ago - it never appeared in the aircraft, and that the Brabazon was designed at a time when it was seen as a replacement for transatlantic liners, not mass movement of hundreds of pax.

Quote:

How strong are those four engines of Brabazon

Eight engines.

http://www.unrealaircraft.com/classics/images/brabaz_eng.jpeg

On the only prototype completed, 8 Bristol Centaurus (as found on the Hawker Sea Fury amongst others), which were about 2,650hp each, coupled in pairs driving contra-props. On the second prototype and the production models it was intended to have 4 coupled Proteus (8 Bristol Proteus', as seen later as single units on the Bristol Britannia, coupled in pairs). The single Proteus was rated around 4,000hp, so in total about 32,000hp (along with around 6,500lb residual thrust from the exhuasts.

I haven't seen any take off and landing performance figures, but as an idea, the runway at Bristol's factory at Filton was extended to 8000ft. Looking at the basic figures I'd suggest it had a take off speed of around 100-130kts, and landing speeds slightly lower. The text below is quite interesting:

Quote:

Construction commenced on the Brabazon in October 1945, in a specially-built 8-acre assembly building adjoining a new, strengthened 8,000 ft. runway. This last structure was built in the face of an out-of-date Civil Airworthiness Requirement, which insisted upon the use of runways no longer than 2,000 feet, forcing a landing speed of around 60 mph. This in turn demanded a low wing loading, and thus an increased wing area. Long, narrow wings are more efficient, having lower drag, but long, strong wings were demanding on the techniques of the time, and tended to be heavy.

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Reply #2 - Mar 22^nd, 2008 at 2:28pm

Hagar Offline
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I found an interesting compilation of newsreels on the Brabazon here ---> http://www.youtube.com/watch?v=miRV-SgYx7Q

This shows the interior of the aircraft & Bristol's chief test pilot Bill Pegg answers your questions on performance in his post test flight interview.

Quote:

In view of the Brabazon low wing loading, what are its approach speed and landing runway requirements?

How strong are those four engines of Brabazon, and how much runway does Brabazon need to accelerate to take off?

Remember that this is the first flight of the one & only prototype & note that these are Imperial measurements.

Off the ground in 500 - 600 yards
Approach - 100 knots
Landing distance about 600 yards

Also note that it had reversible pitch props.

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Reply #3 - Mar 22^nd, 2008 at 2:43pm

C Offline
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Hagar wrote on Mar 22^nd, 2008 at 2:28pm:

Quote:

In view of the Brabazon low wing loading, what are its approach speed and landing runway requirements?
How strong are those four engines of Brabazon, and how much runway does Brabazon need to accelerate to take off?

Remember that this is the first flight of the one & only prototype & note that these are Imperial measurements.

Off the ground in 500 - 600 yards
Approach - 100 knots
Landing distance about 600 yards

Also note that it had reversible pitch props.

Sounds reasonable, particularly bearing in mind it's a prop driven aircraft, so would have more "bite" on initial acceleration, and even an aircraft such as the VC10 (jet, very swept wing) could operate safely from 4000ft of concrete (ie Brooklands). It would of course have been lightly loaded too.

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Reply #4 - Mar 22^nd, 2008 at 5:00pm

chornedsnorkack Offline
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Hagar wrote on Mar 22^nd, 2008 at 2:28pm:

I found an interesting compilation of newsreels on the Brabazon here ---> http://www.youtube.com/watch?v=miRV-SgYx7Q

This shows the interior of the aircraft

Excellent. So, double aisle was an option...
Hagar wrote on Mar 22^nd, 2008 at 2:28pm:

& Bristol's chief test pilot Bill Pegg answers your questions on performance in his post test flight interview.

Quote:

In view of the Brabazon low wing loading, what are its approach speed and landing runway requirements?

How strong are those four engines of Brabazon, and how much runway does Brabazon need to accelerate to take off?

Remember that this is the first flight of the one & only prototype & note that these are Imperial measurements.

Off the ground in 500 - 600 yards
Approach - 100 knots
Landing distance about 600 yards

Also note that it had reversible pitch props.

For comparison, the wing loading looks similar to DC-4, and lower than DC-6 or Constellation wing loading.

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Reply #5 - May 3^rd, 2008 at 5:12pm

garryrussell Offline
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The production Brabazon was to have Bristol Proteus Turbo-Props so would have been a lot more powerful

Garry

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Reply #6 - May 3^rd, 2008 at 5:28pm

expat Offline
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I know only one thing about the Brabazon............It was the only aircraft ever built that had a "you have landed" light in the cockpit. The landing was so soft the pilots requested to have it as conformation that they where actually on the ground and not still floating.

Matt

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Reply #7 - May 4^th, 2008 at 3:47am

Ivan Offline
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expat wrote on May 3^rd, 2008 at 5:28pm:

I know only one thing about the Brabazon............It was the only aircraft ever built that had a "you have landed" light in the cockpit. The landing was so soft the pilots requested to have it as conformation that they where actually on the ground and not still floating.

Matt

Ever seen a Yak-18... that has a 'you are airborne' light... same but in reverse

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Reply #8 - May 21^st, 2008 at 3:27am

pepper_airborne Offline
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Ivan wrote on May 4^th, 2008 at 3:47am:

expat wrote on May 3^rd, 2008 at 5:28pm:

I know only one thing about the Brabazon............It was the only aircraft ever built that had a "you have landed" light in the cockpit. The landing was so soft the pilots requested to have it as conformation that they where actually on the ground and not still floating.

Matt

Ever seen a Yak-18... that has a 'you are airborne' light... same but in reverse

You wouldnt want to be caught retracting your gear whilst still on the runway, it looks messy and leaves the passengers with a bad feeling eh? Grin

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Reply #9 - May 21^st, 2008 at 4:47am

expat Offline
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pepper_airborne wrote on May 21^st, 2008 at 3:27am:

Ivan wrote on May 4^th, 2008 at 3:47am:

expat wrote on May 3^rd, 2008 at 5:28pm:

I know only one thing about the Brabazon............It was the only aircraft ever built that had a "you have landed" light in the cockpit. The landing was so soft the pilots requested to have it as conformation that they where actually on the ground and not still floating.

Matt

Ever seen a Yak-18... that has a 'you are airborne' light... same but in reverse

You wouldnt want to be caught retracting your gear whilst still on the runway, it looks messy and leaves the passengers with a bad feeling eh? Grin

But makes for a good you tube video Roll Eyes

Matt

PETA People Eating Tasty Animals.

B1 Boeing 737-800 and Dash8 Q-400

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