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Avro 693

PMN1

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From ‘Stuck on the Drawing Board’ by Richard Payne

Avro’s original projects against the Type 3 Specifications were the Avro 690 and 692 (or Avro XXII and XXIII), both powered by six Rolls-Royce Merlin 100 engines. These were superseded by the Avro 693 in 1945, which began life powered by four paired Rolls-Royce Clyde turboprops with contra rotating propellers. This paired option was then dropped for safety reasons by the time an order was placed for two prototype 693’s in April 1946. But the project evolved with proposals for Armstrong Siddeley Python turboprops, and then, finally four Rolls-Royce AJ65 (later Avon) turbojets).

The 693 was a large airliner and by December 1946, the design featured a fuselage some 110ft long with a high wing 135ft span, and wing area of around 2,700sq.ft. It was larger than the other jetliner proposed by the Brabazon Committee, the Type 4 project that became the Comet, and could carry forty day or twenty night passengers. The four Rolls-Royce AJ.65 engines, each 6,500lb static thrust, were integrated within the wing, with the tailpalne mounted midway on the fin. A cruising speed of 436mph at 40,000ft was envisaged. It would have a range of 3,513 miles with a 7,500lb payload. A decision was made to go ahead with the 693 in November 1946 but, as the project progressed, it became clear that BOAC would have no need for two jetliners. With the airline backing the DH106 (Type 4), it could not justify introducing two completely new and advanced jetliners into its fleet. On 1 January 1947, the carrier announced it was not going to order yet another British jet but it was not until July 1947 that the prototype orders for the 693 were cancelled and the type became the only one of the Brabazon Committee designs not to be built

Dec 1946 Spec Length 110ft, Span 135ft, Height 27ft 6in, Wing Area 2,700sq.ft


There is a drawing of the turboprop version but nothing of the jjet version.

Does anyone have any more on this aircraft?
 

Caravellarella

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Dear PMN1, I don't have any other drawings of the Avro 693 to hand, but I will say that it appears to be a curious design. Despite retaining a high-wing layout, it doesn't seem to be comparable to the post-war norm of a pressurised parallel-section flat-floor fuselage.

The Douglas DC-4/6 family set the standard;

For non-parallel fuselage design competitors, there was relatively little commercial success. Think especially of the Lockheed Constellation, the Airspeed Ambassador and S.N.C.A.S.O SO.30 Bellatrix/Bretagne series......

For non-flat cabin floor design competitors, again the impediment of a stepped/non-continuous floor must have contributed to commercial failure. Think of the S.N.C.A.S.E SE.2010 Armagnac, the Bristol Brabazon, the Tupolev TU-70/75, TU-104/110, TU-114 and TU-124 for example......

Even the De Havilland DH106 Comet series was handicapped by a fixed structural bulkhead in line with the front spar; not the best and most flexible way to design for efficient volume/payload. What chance then for the Avro 693 with a highly compartmented and non-continuous interior?

Best wishes, Terry (Caravellarella)
 

lark

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For the people who still adore their collection of old AirEnthusiast,
There a description and illustration of the jetpowered Avro 693 in
Air Enthusiast issue 26.(page 76)

The projects is also illustrated (R.R.Avon powered version)
in the vintage"Alles over Straalvliegtuigen"
by the late Hugo Hooftman-La Rieviére & Voorhoeve-1963. Netherland.
 

smurf

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My old Air Enthusiasts are labelled "Vol X number Y" where Y is always 12 or less.
When was number 26, please?
 

Antonio

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When was number 26, please?

...December 1984 - March 1985

http://www.aeroflight.co.uk/mags/uk/air_enthusiast.htm

;)
 

smurf

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Thanks, Pometablava.
My Air Enthusiast series begins vol1 number1 1971 but I haven't any later than 1975.
Part of the time it seems to have been joint with Air International, but all my binders are AE.
 

Kim Margosein

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The current "Air International" at the beginning was known as Air Enthusiast. It then became Air Enthusiast International, then Air International. Around the mid-70s it came out with a spine-back magazine broadly similar in size to the World Air Power Journal, called Air Enthusiast Quarterly. It then went to a bimonthly simply named Air Enthusiast, and then ceased publication about a year ago. Rather than vol/issue, it was numbered 1,2,etc.
Kim Margosein
 

robunos

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i found it, i found it!!

from Air Enthusiast, number 26, page 76,

cheers,
Robin.
 

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lark

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That's the beauty ;D
Thanks for posting ...
 

robunos

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no problem, my library is _slowly_ starting to emerge from hibernation... :)

is it me, or does this plane look more like a bomber than an airliner?, were avro trying a trick, using brabazon funding to finance a military prototype?

cheers,
Robin.
 

lark

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No mention about in the article, but bug-eyed canopies
were a bit the fashion of the day.
(Globemaster I - Douglas Jetmaster..)
 

alertken

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robunos: were Avro trying a trick, using Brabazon funding to finance a military prototype? Yes; but not Avro - Ministers.
By 1944 we knew that little military business would exist after imminent Victory (no enemy beyond tribal pacification), that little civil business would arise until a prosperous world emerged - maybe 10 years on, and that from a big home market US would jostle in every market. MAP judged that turbines would be UK's only Unique Selling Proposition, but (to be BSAAC and BOAC) saw turbines sceptically - 100 hours life was not being attained, when L-049 and (to be) DC-6 expected >1,000 on economic pistons. Treasury could not (legally) subsidise civil work from War-driven taxes, UK could not use Lend/Lease aluminium for purposes that did not represent "defense of US". So: Brabazon Committee Types prototypes had (often notional) military serials to earn their place in the queue for US raw materials; their bespoke engine R&D (Clyde/Proteus, big Centaurus) were covered by vague military Targets (future Bomber? what? why? no enemy). Design was covered by RAF Specs as military cargo/troopers to legitimise funding. That stratagem persisted in Peace: SR.45 (Princess) had a dual MR Spec; DH.106 (to be Comet) was military twice-over in 1944/46: as an "Express" mail/freight/VIP mover (= Admiral's barge), and as a trial for a tail-less jet-Mosquito. It was not until late-1946 that Brab Type IIIC (to which Avro 693 was funded) settled in MoS eyes as a Medium Range Empire. MoS continued to fund 693, despite BOAC disinterest, to sustain the team scheming a delta Medium Bomber. BOAC invited a piston tender, Mark 1, compatible with a propellor-turbine Mark 2. Step forward Britannia (selected 14/7/47), and Vulcan (selected 28/7/47); step out 693.
 

fredgell

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There is a rough description of this project in 'Stuck on the Drawing Board'

I was wondering if the advert on the cover of Flight
http://www.flightglobal.com/pdfarchive/view/1945/1945%20-%200679.html

might actualy be an impression of a version of this aircraft
The date and configuration is just about right...

Regards

Fred
 

Jemiba

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IIRC, we've already seen this advert here in another thread, but we
couldn't recognise a special type. The shown aircraft seems to feature
some deHavilland attributes (shape of the fins and wing) and I cannot
see any intake for the jet engines. And the company, which launched
this advert isn't really an aviation company, but producing some sort of
coating. so for me it's plausible, that the advert is just showing a purely
fictious type.
 

robunos

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See here...

http://www.secretprojects.co.uk/forum/index.php/topic,3988.msg31265.html#msg31265

cheers,
Robin.
 

fredgell

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Perhpas shouldn't have raised this as a new heading - I did a search but it didn't show the preceeding thread as such - should have looked harder.

My thought was that the design might represent a first pass at the change from props to jet - hence the underslung arrangement and engine spacing on wing.

The body shape and length appears roughly right - well within 'artistic licence'

Regards

Fred
 

Jemiba

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You even may be right, that the artist was influenced by the Avro 693.
I've searched again for the thread, where Hesham posted this advert,
but without success still yet, but AFAIK the 693 wasn't mentioned there.
To my opinion, this company had asked for a picture with a "modern airliner"
and got this one. I've seen adverts from Rolly Royce, I think, showing VTOL
transports, similar to the Do 31 or soem Bristol projects, but without real
relationship to them.
The only way to know for sure, may be to ask the artist himself ... ;)
 

PMN1

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Any suggestions as to the impact if both this and the DH 106 Comet or even just the Avro 693 rather than the DH 106 Comet had been chosen for development?
 

alertken

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MoS' perception, 1945/48, was that UK firms might be able to do one thing at a time, and that one each was enough, as we had excess R&D capacity (not competence). Avro's Medium Bomber scheme looked good, so delete 693.

If in 1946 BSAAC/BOAC had carried the case for a turbine-powered, $-earning Connie-buster, and if they had chosen commercial virgin Avro (why would they, when Vickers and others had comparable schemes), then T.167 Brabazon would have been abandoned, T.175 Britannia never started. Victor as prime Medium Bomber, Valiant as insurance, even inc. Mk.2. What ifs from that ripple endlessly (no Concorde, as Bristol, Buckingham/Brigand incompetents, would have exited airframes after a few T.170s).

693 was Theseus or Clyde in 1945, AJ.65 in 1946: if RR+HSAL had been funded then, a family of turboprop/turbojet transports might have been in Service by 1950, destroying Convair/Douglas' pretensions, deterring Boeing from doubling their failed B.377 throw.
 

hesham

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We must merge those topics;

http://www.secretprojects.co.uk/forum/index.php/topic,5856.msg47410.html#msg47410
 

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