Any landing you can walk away from, is a good one.
13 January 2009
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Does anyone have any good pics of the Saro A.33 flying boat to the same R.2/33 Specification as the Short Sunderland?
Here the "great" airplane : the incident of K4773 was reason of end of development of Saunders-Roe A.33

so watching on :

specifications of R.2/33 was awesome for Short Sunderland and Saunders-Roe A.33

So A.33 was less lucky :)


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The A.33 is covered on pages 162 to 170 of Saunders and Saro Aircraft since 1917, Peter London, Putnam 1988.
The section has seven photos of the A.33 (three of the aircraft after the wing failure) and one of Saro Cloud K26881
modified to test the Monospar wing and sponsons of the A.33.
The 3-view and photo posed by airman are both in the Putnam.

The wing failed after the aircraft hit the wake of a Southampton ferry while on a take-off run, the A.33 began to porpoise severely,
porpoising was a problem with the aircraft, the A.33 leapt into the air and came down out of control in a stalled condition. At impact
the wing failed in torsion at a point inline with the starboard inner engine which caused the starboard leading edge to pivot around
the single-spar driving the propeller into the fuselage and sponson, missing designer Henry Knowler by inches.

Photos of the A.33 from Tagg/Wheeler "From Sea To Air" :


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Re: Saunders-Roe A.33 flying boat prototype......

As far as I can tell, the A.33's wing was only supported by those angled struts from the "seawings". Is it any wonder it collapsed under stress? Does any one have any air-to-air shots?

Terry (Caravellarella)
Re: Saunders-Roe A.33 flying boat prototype......

Dear Boys & Girls, here is an image I had found of a book jacket showing the A.33 prototype. Sorry I can't remember where the image came from, but look at all that thin air between the fuselage and the wing......

Terry (Caravellarella)


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Taxiing trials of the prototype (K4773) was started on 10 October, 1938.
First flight was made on 14 October, 1938.
Take-off was uncomfortable due to porpoising tendency.
The damage was made during its fifth take-off on 25 October, 1938. The aircraft hit the wake and lose control. The starboard inner airscrew penetrated the hull and starboard sponson. The tail was damaged by flying debris of the wing.


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Four additional pictures of the beautiful A.33:


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joncarrfarrelly said:
At impact the wing failed in torsion at a point inline with the starboard inner engine which caused the starboard leading edge to pivot around the single-spar driving the propeller into the fuselage and sponson, missing designer Henry Knowler by inches.

I trust he was suitably scared enough for a new pair of trousers - adequate punishment for screwing up the design!! Actually that's the good thing about large aircraft - you can put the designer aboard for the first flight and carefully watch their face on takeoff. If they're either too happy or at all scared, you know to say your prayers. ;D
I think I would have added a dorsal brace, to be sure, to be sure...
Does anyone know the purpose of the dorsal fairing just forward of the vertical tail? It looks like something pasted onto an existing design as an afterthought, not part of a new prototype.
Two beam positions under sliding hatches in the large dorsal hump forward of the fin were to be armed with single, pillar-mounted Vickers K guns.
From 'Saunders and Saro aircraft since 1917' by Peter London, Putnam 1988.

The aperture is visible in pic 'Saunders Roe A33 Flying Boat-04.jpg' as posted by Stéphane.
I wonder if the porpoising had anything to do with the fact that its beam gun positions are well aft (doubtless because of that high strutted wing; the Sunderland had its at the wing trailing edge much further forward) AND it has a tail turret (though that seems to be fitted for but not with in these pics), so its CG is going to be somewhat rearward, or just the hull shape, or a combination of both.

Does anyone know if there was a formal investigation into the torsion failure of the wing spars? Or was the stall-crash of the sort that any reasonable wing would fail?
According to Peter London, the A.33 was probably never fitted with a tail turret. In the same book, he describes porpoising in the Saro A.36 Lerwick. Saro seemed to have developed a knack for porpoising by design; then again, maybe just bad luck.
What was the estimated performance compared to the Sunderland?
'British Flying Boats' (Peter London) has a picture taken after the accident. "Failed in torsion" is a fair description of the damage to the wing... ;)

Sorry, can't scan the book at this time.
:D Aircraft performance Powerplant: four 830-horsepower engine Bristol Perseus XII
a wingspan of 95 feet (28.956 meters)
Length 75 ft (22.86 m)
height 22 feet 8½ dym (6.922 m)
Wing Area 1194 ft² (110.926 m²)
during the first flight of 31,500 lb (14,288.4 kg)
maximum during testing 35,000 lbs (15,876 kg)
Design maximum 41,500 lb. (18,824.4 kg)
Project cargo handling 44650 lb. (20,253.24 kg)
Flight characteristics:
maximum speed of 200 miles / hour (321.8 km / h)
Maximum cruising speed 174 miles / hour (279.966 km / h)
cruising speed for flight namaksimalnuyu range of 155 miles / hour (249.395 km / h)
It rises to a height of 3300 feet, 8 minutes 20 seconds
service ceiling of 14,280 ft (4352.544 m)
the normal duration of the flight 12 hours
the maximum duration of the flight 13 hours 25 min
Armament: One or more of 0.303 "(7.7 mm) Browning machine guns in the front and back of the towers, two machine guns Vickers K in the forward position of 2000 lbs (907.2 kg) bomb nagruzkis on underwing mountings on the outer sides of the sponsons
Production: one instance, K4773


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What was Saro's production capacity used for after cancellation....there was the Lerwick, the less said about that the better.
PMN1 said:
What was Saro's production capacity used for after cancellation....there was the Lerwick, the less said about that the better.

Walrus and Sea Otter.
Be interesting to know what kind of production rate Saro could have maintained for the A.33 ha did not had its problems and the order had been continued or extended.
PMN1: you are tussling with evident under-use of the Columbine cavern of Cowes. The actual A to your Q is: same as all other UK Aero firms in 1935: this modest sector, good at sculpting one-offs in sheds, no expertise at churning out in quantity: that had lapsed in 1919. Volume was not a matter for the design firm - none had any such competence: Air Ministry's Procurement folk handled that, and, for example, would organise who got how many Perseus, when.

1935. Capital markets saw Rearmament, especially Aero, as the of the day. Saro's owner, Lord Cowdray's Pearson, spent to build Columbine, secure that Saro's place in A.M's Ring closed shop was in the marine sector, with a nice learning template order for 48 A.27 London (about as much business again as their entire previous output). Much more to come on A.33, then on S.36 Lerwick because marine competitors Short would be consumed on Stirling, Blackburn on Botha, Supermarine on Spitfire, so boats would be mine, all mine. Nobody saw the Solent as vulnerable - the Maginot Line would keep German short-range bombers far away.

A.M agreed and accepted into overhead expense in 1937 a hangar at Eastleigh and, 1939, the Medina hangar at Cowes. If A.M had chosen to churn out A.33/S.36, then labour, transport, materials and engines would have been supplied. Saro's job, like all others in Aero, would have been to be truly grateful to Embody that which A.M had Loaned.

When A.33/S.36 were seen as busted flushes A.M ramped up Sunderlands in distant Belfast, Dumbarton, Windermere and bought Catalinas for cash - occupying Saro as Sister Firm, safe at Beaumaris. After 6/40 large structure in Cowes, impossible to disguise and in Heinkel range, could not be filled with hi-valu targets. So: sub-contract parts, inc. for Walrus and Sea Otter, assembled at Somerton and (Walrus) at Weybridge (190 Walrus II wooden hulls came from Elliotts of Newbury, who also made 700 Oxford fuselages, because their site was less exposed than Cowes or Airspeed-on-the-coast).

A.M's vast Eastleigh Agency Factory (to be occupied by Cunliffe-Owen) was similarly under-utilised.

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