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Author Topic: Saunders-Roe Princess, Duchess, P.192 and other Flying boat projects  (Read 71500 times)

Offline Skyblazer

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Re: Saunders-Roe Princess, Duchess, P.192 and other Flying boat projects
« Reply #105 on: September 16, 2014, 03:50:36 am »
The idea behind a hull is for it to be INSIDE the water... Your simulation has the hull part completely OUTSIDE the water!

I do agree though that there doesn't seem to be enough hull on this design. Here is my own understanding of what it would look like (probably not perfect either, and open to criticism):

Offline Abraham Gubler

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Re: Saunders-Roe Princess, Duchess, P.192 and other Flying boat projects
« Reply #106 on: September 16, 2014, 04:12:33 am »
About take-off of a flying boat with this configuration, I must admit, that it really got me stumped.
 I tried to show, what I had in mind. Generally, the auxiliary floats are more or less on a level with
 the point of rotation. I think. If the aircraft hits a wave, it is lifted by its buoyancy and (if all works
 well !) the aux floats are lifted, too by the same amount. Positioning them aft could mean, that the
 fuselage is dropping into a wave trough, but the floats are just on the peak of a wave. As you wrote
 about your Grand-Dad, that happened in conventional designs, too, sometimes with unfortunate
 results. But a conventional in most cases was designed to avoid the waves.
 But as said before, I'm definitely not knowledgeable enough for such problems.
 

I understood what you were saying before and for the fun of it have added a similar image about the effect of the aft floats on rotation to lever the hull out of the water (unsticking). But I guess if a wave hits the flying boat at takeoff while rotating the floats wonít automatically submerge because they have their own very high buoyancy which will be displaced by the sea. So assuming the airframe is stressed to withstand these different forces applying on its length this will lift the entire aircraft upwards as the main hull is on the peak of a wave and has its own upwards displacement force. If the wing is producing enough lift it will start to fly just like rotation on flat water. However if the wing canít lift the flying boat then you will be back to where you were before rotation and running at a level attitude across the top of the waves.
"There is a tendency in our planning to confuse the unfamiliar with the improbable." Thomas Schelling

Offline Bill Walker

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Re: Saunders-Roe Princess, Duchess, P.192 and other Flying boat projects
« Reply #107 on: September 16, 2014, 04:42:42 am »
An interesting thread.  From my experience testing flying boats (part of the certification team on the Trident Trigull) I can offer a few extra points to ponder about those rear mounted floats.

First, the hull is only IN the water at low speeds.  The forward hull is designed to act as a ski, and lift the hull using the planing forces at higher speeds.  This allows faster acceleration in the second segment of the take off run, by reducing water drag.

Second, the shape of the forward hull has a major impact on the shape of the water immediately behind the hull.  The NACA developed single step narrow hull, as used on the Trigull and later Martin boat hulls produces a large depression in the wake behind the step. This provides a volume of air into which the tail can lower when rotation occurs.  You get the increased wing lift, without water drag or buoyant forces changing your pitch moments.  A conventional boat hull needs a second step, placing the tail behind the second step well above the waterline, giving room for the tail to drop upon rotation.

The picture of the wake behind the aircraft in Jemiba's posts above starts to get this idea, but a well designed hull puts the peak wave in the wake well behind the aircraft.  That is an interesting hull shape on this aircraft, maybe the rear placed lateral floats would have had an air volume to rotate down into.

And, from personal experience, having a wave hit a tip float, and even briefly submerge the tip float, will slow you down a bit, but it is not always catastrophic.  Submerging more of the tip float just produces more buoyant force trying to raise the float.
« Last Edit: September 16, 2014, 04:49:08 am by Bill Walker »
Bill Walker

Offline Skyblazer

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Re: Saunders-Roe Princess, Duchess, P.192 and other Flying boat projects
« Reply #108 on: September 16, 2014, 04:56:49 am »
Very interesting Bill, thanks a lot for the insight and for sharing your experience.

Offline Abraham Gubler

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Re: Saunders-Roe Princess, Duchess, P.192 and other Flying boat projects
« Reply #109 on: September 16, 2014, 05:36:12 am »
Thanks for the input Bill.


The aft floats are located outboard of the centreline and might very well be outside the wake of the main hull. In which case they might not be affected by the effect on the surface of the water caused by a planning hull.
"There is a tendency in our planning to confuse the unfamiliar with the improbable." Thomas Schelling

Offline alertken

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Re: Saunders-Roe Princess, Duchess, P.192 and other Flying boat projects
« Reply #110 on: September 16, 2014, 05:40:10 am »
By co-incidence, Flight  last week has agreement for India to licence Shinmaywa US-2A: islands patrol.

Online Jemiba

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Re: Saunders-Roe Princess, Duchess, P.192 and other Flying boat projects
« Reply #111 on: September 16, 2014, 07:06:26 am »
Interesting insights, many thanks ! I had no idea of the intentional use of the wake
for allowing the tail to be lowered.

@ Sky: Your drawing pobably shows well, what the flying boat would look at its mooring,
but the important moment to my opinion is just before lifting out of the water, or when
it just touches the surface during landing. And then only a very small part of the hull
would be still in the water, I think.
It takes a long time, before all mistakes are made ...

Offline Bill Walker

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Re: Saunders-Roe Princess, Duchess, P.192 and other Flying boat projects
« Reply #112 on: September 16, 2014, 11:08:45 am »
I'm just guessing here, but I think that in order for this hull and float combination to work the lateral floats would have to be INSIDE the depressed wake behind the step.  This gives them room to drop when the nose is raised (the aircraft will tend to pivot around the step).  The forward shape of this hull looks "unusual" to me, so I can't tell if this would really happen.  On a NACA style single step narrow hull, the cavity behind the step is fairly narrow, just wide enough for a pointy aft fuselage to drop in to.

Of course, there may be a very good reason this configuration was never built :).
Bill Walker

Offline alertken

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Re: Saunders-Roe Princess, Duchess, P.192 and other Flying boat projects
« Reply #113 on: April 13, 2015, 08:21:52 am »
Confusion: Princess (military, civil), Saro P.104, P.162, Short P.D.2.
 
(Here: "portly" is to mean broad beam, Sunderland-esque; "parasol" to be Catalina-esque; "slender" hull is Martin P5M Marlin-esque).
Refs:
1. Princess: www.fzt.haw-hamburg.de/pers/Scholz/dglr/hh/text_2010_06_03_SR_Princess.pdf,  fr. page 51. RAF page 173.
2. Buttler/Bombers,2004, P.143: portly twin-fin, dorsal turret "VS T.524, early-1949"
3. Flight cover, 26/2/54: the same image, no dorsal turret: "Saro Ocean Patrol Concept" (elsewhere stated as Nomad/P.162)
4. (CJG) Gibson/Nimrod Genesis, P.29, portly T-tail Saro P.162/6 (after 1951; wholly different to ref 3)
5. CJG/Nimrod Genesis, p.57, portly Short P.D.2, 7/49
6. CJG/Nimrod Genesis, Pp.51/66: parasol P.D.2 (after 7/49), near-identical to:
7. CJG/Nimrod Genesis,P.49: parasol Saro P.104/1 (5/49)
8. Robunos, here, Designation Systems: Saro: 14 P.104s dated 1948-53; P.162s 1952-56.

CJG/Nimrod Genesis, P.59
has R.4/48 Sunderland replacement "won" 7/49 by portly P.104/3; not funded; parasol P.D.2 funded "by 1950".

If
ref.2 is wrong (though it is credited to V-S historian E.Morgan) and is a P.162 (so later than early-1949); and if CJG, ref. 6, parasol P.D.2, is correct: then is this what happened?

A.Gouge
designs Shetland, 1942: he prefers portly boats; MAP imposes Saro (H.Knowler) to design the wing. MAP takesover Short, 23/3/43; Gouge to Saro: they scheme broad beams. Pay, 1945, to put big boats with vague markings on mag. covers. Why? UK was awash in Sunderlands (inc. straight from shop to chop), averse to Mariners, Coronados.

1/11/45 new Govt. policy: BSAAC to link UK-Argentina, happy to trade in £. 1945-50 UK will swap lots - retread Magister, Sandringham, heavens! even Prentice - for spam {yes, that's the word's origin}. Onway, more ports than airports. We need a big marine transport, even overlapping with Brabazon Committee's Type I Transatlantic landplane (Bristol T.167). MAP Spec. 10/46 to tender. SR.45 funded 5/46, 1 prototype+3 for BSAAC. Portly. Traditionally built, broad in the beam.

UK, no MR interest - no enemy at sea. USN 6/46 funds the new notion of slender hull, by changing Mariner to Marlin. RAE thinks about it, Gouge/Knowler do not. CAS extracts funds, late-46, to supplement Sunderland G.R.V/Lancaster G.R.III with (to be) Shackleton M.R.1 (Tudor having failed, a prime candidate for any future Medium Bomber needed succour).

14/4/48: Cabinet declares USSR as world-wide Threat. Bombers, fighters awa'!...RAF marine MR Requirement out to tender; back 4/49 as portly T.524, P.D.2, P.104/3 - which, 7/49, is preferred (V-S busy, now, on (to be) Swift; V-A to help little Saro build boats apace)...ah, but...what about our empty SB&H/Sydenham. Pause for thought.

(By 1950) Saro's slender parasol P.104/1, Marlin-inspired (USN has more such slimlines in work), ah, inspires new P.D.2, MoS trickle-funded in design. BSAAC dies, 15/3/49; BOAC (for whom MCA orders 4 Princesses, 1948) by early-49 elects to abandon marine (so, 10/11/50). SR.45 should then have been aborted...but 1/1/50 new CAS MRAF Slessor had been AOC Coastal Command, 2/43-1/44. So, options open, SR.45 trickles on to flight 22/8/52, on MoS "Research" budget.

From 8/50, Korean War, UK basks in vast cascades of $, funding more Shackletons, loaning Neptunes. Saro pitches P.162s, Princess, Duchess variants 1952-54 to deaf ears until Cabinet, 14/1/55 says enough already, get on with Medium Bombers. Saro into DH, 9/56, Westland, 7/59 and Sir Arthur Gouge retires. 



 
 
 

Offline Schneiderman

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Re: Saunders-Roe Princess, Duchess, P.192 and other Flying boat projects
« Reply #114 on: April 13, 2015, 08:42:10 am »
alertken,

I think that is about right but I would throw into the mix this succession of articles in Flight to add some context. The catalyst for the argument appears to have been the lack of support for flying boats from the Brabazon Committee.

Knowler  The Case for the Flying Boat  25th Nov 1943
Pollitt    Where Angels Fear  16th Dec 1943
Knowler  The Case for the Flying Boat(2)   6th Jan 1944
Kemp   The Future of the Flying Boat  27th Jan 1944
Gouge   Flying Boats  10th Feb 1944
Pollitt   The Flying Boat  24th Feb 1944
Gouge  Flying Boat Morrings 3rd May 1945

All at http://www.flightglobal.com/pdfarchive/index.html


Offline alertken

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Re: Saunders-Roe Princess, Duchess, P.192 and other Flying boat projects
« Reply #115 on: April 14, 2015, 03:38:53 am »
S: thank you.

Offline CJGibson

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Re: Saunders-Roe Princess, Duchess, P.192 and other Flying boat projects
« Reply #116 on: April 14, 2015, 03:58:04 am »
Ken, nice to see you're an early buyer! Thanks

Just seen your posts.

I'm doing this from memory. My take on the shenanigans is that Shorts got the R.2/48 job because the MoS wanted them to have it and happy to see Saro go down the pan. Shorts' problem as seen by the Air Staff  was that they wanted a wide fuselage to take passengers and any boat they designed was designed for the civil market (later repeated with Britannic) Saro was deemed a better design than the Shorts, but lost out due to Govt shareholding in Shorts and need to keep employment in Belfast. The notion that Belfast was less vulnerable to Soviet attack than Cowes is risible.

Shorts initial portly PD.2 with nacelle weapons bays was laughed at by the Air Staff who told Shorts that if they were doing the job, they better do it right and sent them off to redesign the PD.2 - Parasol resulting.

By that time the flying boat had gone the way of the airship.

Anyone share any light on the lack of a Blackburn bid for R.2/48? That's listed in all the books but there is not even a mention of Blackburn in the R.2/48 files in Kew.

Also, OR.183 - Amphibious Air Sea Rescue type - The flying boat Catalina was acquired instead. Any idea why or was just the usual 'it was there and cheap'?

Must go - taxi at the door.

Chris

 
« Last Edit: April 16, 2015, 03:20:22 pm by CJGibson »

Offline alertken

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Re: Saunders-Roe Princess, Duchess, P.192 and other Flying boat projects
« Reply #117 on: April 15, 2015, 04:23:29 am »
(Mods: humour us: not Secret but relevent background to schemes and dreams).

Blackburn post-war big boats: the Putnam, P.21 has the Board: "With reluctance, all work on marine projects was brought to an end and Maj.J.D.Rennie, the chief seaplane designer, resigned 5/46" (when his B-49 Clydesman lost to SR.45). So: surmise: its resurrection as scheme B-78 to R.4/48 was throttled when his rump team sought Co. budget to move up to a Tender brochure. Priority was on recovering from detritus of Firebrand and on coming second, with B-54, to Gannet.

Why Catalina? A.C Harris had been underwhelmed, being pitched the kitchen sink in US, 5/38. For GR/ASR we were well-suited with Interim Sunderland onway to definitive Lerwick, insured by B-20, but he acquiesced in 1 Model 28 for MAEE/Felixstowe (arrived, 7/39).
USN enhanced it as PBY-5, ordered 9/39, 40 for France, 12/39, by when...we knew we were not so well-suited. 30 (PBY-5) Catalina I were ordered (for cash money) 1/40 simply to secure some slots. Ditto RAAF, 18, 8/40, in preference to low priority if they ordered Sunderlands. Netherlands E.Indies AF ordered 36, 5/40: if they had thought of Sunderlands, they would also have seen slow delivery as an issue.

So, why, building Stranraers to 11/41, did Canada buy (to be) Canso, 9/40, first batch from US, then from Canadian-Vickers on end of Stranraer line; more from Boeing/Vancouver, 12/40. Some to be amphibs...but: endurance: Qantas would operate Perth-Ceylon, average sector of 27hr.
« Last Edit: April 15, 2015, 06:07:02 am by alertken »

Offline Zeppelin

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Re: Saunders-Roe Princess, Duchess, P.192 and other Flying boat projects
« Reply #118 on: July 15, 2015, 05:43:42 am »
What ever happened with the Python? Did it ever find a production run elsewhere?

Online Arjen

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Re: Saunders-Roe Princess, Duchess, P.192 and other Flying boat projects
« Reply #119 on: July 15, 2015, 06:17:03 am »
The Westland Wyvern was powered by the Python.