Saunders Roe P.177 / SR.177

[PMN1]

I've cut and pasted this from another site

SR.177 is a mixed powerplant interceptor and quite a flexible design to boot.

Japan had a look at it too, and at one point examined weather to buy the SR.53's. and the production jigs.

Had it entered service, its most likely the RAF and RN would follow the Germans and opt for Avon powerplants to start with, considering that by 1960 rocket motors fell from favour.

The RB.106 "Thames" (which was designed to fit into the space for a Avon) would have nearly matched static thrust in reheat with the Gyron Junior and Spectre motors at 21,750lb (Gyron junior made 14,000lb reheated, Spectre was developed to 10,000lb).

Its biggest flaws are:-
1 lack of rear view (like a number of aircraft including the Crusader).
2 small 18-inch diameter dish AI.23 set, though its possible a larger set might be squeezed in (perhaps a 21 inch dish).

Its biggest pluses are:-
1 small size at 50.5ft long (45-ish with nosefold) and roughly 30ft span with a fold down to around 18ft.

2 High performance. Top speed was limited due to cheap materials for mass production. Reduction to jet only would've resulted in a Avon machine doing around mach 1.8 and a "Thames" doing around mach 2. Though ceiling would be down from the rocket powered 1g limit of 97,000ft.

3 Capacious internal volume for either rocket fuel or jet fuel.


There is a bit more information here

http://www.spaceuk.org/index.htm (click on the rocket interceptors section).

http://www.spaceuk.org/sr53/177/sr177.htm

Anyone want to suggest what might have been had it survived the 1957 defence white paper?

 

[LowObservable]

Bill Gunston used to be (maybe still is) a huge fan of the SR.177. The rocket-plus-dry-jet combo gives you some of the same characteristics as an early afterburning turbofan - a choice between not a lot of power in one mode, lots of power and huge fuel burn in the other. And despite the Me163 horror stories, the UK seemed to manage peroxide/kerosene quite well. But rockets on a carrier?

 

[overscan (PaulMM)]

I've never really seen the appeal of SR.177 myself. Afterburning turbojets are less complicated in use, in maintenance and supply train (single engine, not two, single fuel type) and seem a better solution. Other features of the design - T tail - not great - also its pretty fat looking (pre-area-rule, I assume) and like the YF-102 I have trouble seeing it exceed Mach 1, let alone 2. And don't even start on the canopy design.

 

[Jemiba]

"But rockets on a carrier?"

The british navy seems to have had no restrains against rocket fighters
on their carriers. Remember, that the Fairey F.D.1 started its life as a
tail sitter rocket interceptor, especially for aircraft carriers !
Maybe the experiences with kamikazes had deeply shocked the admirality ?

 

[zen]

From memory I wrote that.

From the book Saunders Roe aircraft from 19__(forget the date) comes most of my information (photcopied the whole section on this).

Its likely the rocket would've been dropped by 1960 as they had falled out of favour, so I doubt you'd have seen anything but early prototypes flying with it.

Avon RB.133 gave about 13,000lb of thrust dry, but I don't have figures for its size, though clearly Saro felt they could fit the larger engine, as this was offered to Germany after they began changing their minds over what they wanted their machines to do.

Not that much of a surprise once you realise the orrigin of the design was for the supercruising research requirement that was won by Bristol with its 188, Saro's design used a Gyron (not to be confused with the junior).

So most likely is that the rocket motor is deleted and the RAF would focus on recovering power to keep the machine competative, either following the Germans with the Avon or going for the 'Thames' RB106, though that is unlikely to be in service before 1962.

At one stage HMS Eagle had in her design, two pure aluminium tanks for the HTP storage.
High Test Peroxide is a lot safer and easier to handle than Lox.

 

[Rickshaw]

High Test Peroxide is a lot safer and easier to handle than Lox.

No it is not. HTP is very unstable, particularly in the marine environment. It has been the cause of several large accidents when used as a fuel in torpedos and even is accorded as the reason why the Russian submarine KURSK sank. Its pretty nasty stuff and prone to explosion if any moisture is present. To suggest it is easier to handle than LOX is pretty foolish IMO.

 

[Hood]

HTP is easier to store, LOX cannot sit in the tanks as it evaporates, the SR.177 would have to be fuelled before every sortie, in the three-minute warning world this was a major drawback. It needs to be kept cold too and this complicates onboard storage.

HTP is like water, it can be stored longer but it does evaporate, in fact the more it does so the more explosive it becomes. Therefore diluting any spills with water was deemed to be satisfactory. It is true however that it combusts on contact with leather and some man-made fabrics so the ground crews had to be very careful when handling HTP. Silver and other metals also proved to be good catalysts at getting the reaction going, in fact that is all that was needed to begin the reaction, a silver gauze.

The only byproduct of the reaction is steam, nothing else but kerosene was added to boost the thrust produced. The RAF had many trials with HTP rockets and they mostly went according to plan. Most RAF pilots at the time agreed that they would rather sit in a HTP powered aircraft than LOX. Overall Britain has done the most research on HTP rockets than any other nation for both aircraft and space rockets.

I've more HTP engine details if anyone wants me to post them.

 

[Archibald]

I've never really seen the appeal of SR.177 myself. Afterburning turbojets are less complicated in use, in maintenance and supply train (single engine, not two, single fuel type) and seem a better solution.

This also explain why the Trident was smashed by Durandal and Mirage III-01 in 1957... yes, they were competitors :

 

[zen]

HPT fires can be put out with water.
HTP is corrosive towards carbon impurities in a storage container over time, but a pure metal or glass can hold it safely for a very long time.
Boils at 150 degrees C, freezes I think around -5 (this from my poor memory).

Lox however boils into gas at room temperatures and requires refridgeration and pressurisation to keep it liquid.
Lox burns everything, and the only two options are remove the fuel its burning or dilute the oxigen gas until it can be put out by normal means. Both are rather difficult and the fire is extremly hot, especialy if its burning a metal like iron or aluminium.
A Lox fire next to a pressurised Lox container would be extremely dangerous.

Of course people can be burned by the cold too, and the cold of Lox escaping from its container or even its container itself can be very severe.

Accidents like Kursk and an earlier one in a UK submarine in the 1950s relate to HTP comming into contact with a catalyst, on both occaisions brass is the likely culprit, a small leak into a brass fitting in an enclosed space such as a torpedo room saw HTP catalise into water and oxigen and hydrogen gases, once a spark was added the result was inevitable.
This is why the UK abandoned work on HTP in its fast torpedos after said accident and why it was rather foolish of the Russians to use this cheap liquid for a propellant for one of their torpedos (possibly Shkval).
Proper care and attentions to its storage and use can preclude such accidents.
Thus the pure aluminium tanks on Eagle, with no brass or other catalyst for it to drip into.

HPT is a LOT safer and easier to handle than Lox.

All of which only proves my theory that people get 'rocket blindness' when one mentions the use of a rocket in the Saro P.177. People seem unable to see beyond the rocket to the actual plane itself, which is very sad. Reason being my information suggests the maximum speed limit was forced by teh cheap materials the plane was intended to be made from, which in turn suggests it has excess power enough to go far faster than mach 2 on the combined thrust of a reheated Gyron Junior and a Specter rocket.
Ergo, a reduction in thrust by a move to a jet only powerplant will not be such a reduction in achievable maximum speed, given the materials its made from. The inlet was said to be very good and thats no surprise it seeming to be a two shock type, with an RB106 it certainly should have achieved over mach 1.8 and might have made mach2

 

[Barrington Bond]

I may be wrong but wasn't the rocket intended more for getting it to height quickly to intercept Russian bombers?

Regards,
Barry

ps yes please for more info on HTP rockets.

 

[Hood]

Red Admrial (who posts here) on another board said he had visited the RR Heritige Centre and had a good talk with some of the old engineers there. They thought the SR.177 with the right materials was suitable for M2.7!

Indeed most of the F.155T designs were capable of higher speeds with the right robust materials. I hope BSP Vol 4 reveals more about British efforts in the high-mach range, especially structures and metals.

Give me a few days and I'll dig out some more on the SR.177 and British HTP rockets in general.

 

[zen]

Red Admrial (who posts here) on another board said he had visited the RR Heritige Centre and had a good talk with some of the old engineers there. They thought the SR.177 with the right materials was suitable for M2.7!

I would not be surprised, but that relates to the nature of rockets which rather increase in performance at altitude though of course they need to be optimised for a specific air density, likey the Specter was optimised for around 60,000ft required.
But what that means is that one should'nt think Saro's machine could do mach 2 on the Gyron Junior alone, rather that a even with a net drop in static thrust nevertheless a larger engine should drive the machine to a very respectable performance.

24,000lb static thrust at sea level for a 28,000lb (with drop tanks) aircraft clearly would give rather superlative performance for a mid 50's design. Some have suggested it would be limited to the larger carriers in the RN, but that sort of power on that kind of weight, with such a wing should permit the full limit of operations even from HMS Hermes if not right on to a modernised Colossus/Majestic carrier.

 

[red admiral]

The Rolls-Royce engineers seemed pretty confident that their rockets could do the job nicely. Fast climb to 60000ft with rocket+jet in about a minute and then loiter subsonic on the jet before using the rocket for a quick interception. In their opinion the S.177 would have been good for a nominal Mach 2.70 and would not have been safe to fly at speeds above this due the aerodynamic heating effect on the alu-alloys used. Altitude also became a problem, it being marginally safe to fly up to 80,000ft but becoming increasingly dangerous. The test pilots on the SR.53 were forbidden from doing any zoom climbs as it was expected to reach about 120,000ft before falling over on it's back and plunging a long, long way down.

 

[overscan (PaulMM)]

Technical Report

http://naca.central.cranfield.ac.uk/reports/arc/cp/0710.pdf

 

[zen]

Wow!

Will need to dig though this.

However....it seems TO speeds with blow are between 141-160kts at 28,300lb and landing speeds are between 99-141kts at 17,000lb.

Its of note the energy of landing is low compared to the likes of the Scimitar let alone an F4 of any colour. This should've made it easier to operate, launching at lower WOD speeds and recovering at lower WOD too.

Certainly within the mk13 arrestor gears potential to bring to full stop and the mk4 catapult to launch make Colossus/Hermes type carriers capable of operating this type.

Seems the canard was a disappointment, they needed to move the wing back to really gain from it by their own opinion, but they thought it possible to achieve that. So was there any further study in that direction?

Curious question is why there was no serious canard design for an RN fighter in this periode!
Vickers where dead keen on it for large bombers and the F155T tender.
Fairy and Bristol thought a canard layout adequet for GOR.339

But I've not seen a canard design for OR346 or AW406.

 

[alertken]

1952-55: what a time to be in aero design! Korean War, seen as prelude to incursion into W.Germany, stimulated spend. US/UK funded almost anything that seemed to offer quality v.WarPac quantity. Even schemes at minnows unable to build in quantity. So to protect sales of their rocket motors DH bought 33% Saro equity when they won P.177. SR177 would have been led at Cowes, built at (DH, ex-Airspeed) Christchurch, and flown from Hurn.

Deletion was due to: 1. general Defence funding cutback when USSR showed signs of sanity after Stalin; 2. RR solving reheat such as to put P1B (Lightning) close enough to where SR177 would be; 3. US funding the NATO Hawk SAM belt, embracing N.Norway, to cull high incoming Sov bombers before entering any UK defences. UK did not need to take on this expense. P1B only survived because its order, 20 DB plus 50 F.1, preceded new PM Macmillan hunting for economies and was presented as irrevocably committed past-the-point of savings.

 

[Barrington Bond]

From Jabberwock No 16 January 1987.

 

[Weaver]

The T-tail has always made me dubious of how well the SR.177 would have fared in in the kind of actual combat that 1950s fighters found themselves in in the 1960s, i.e. tactical dogfights, rather than high-altitude bomber interceptions. Might it have ended up as Britain's Starfighter?

 

[Barrington Bond]

:-\

 

[zen]

Really needed a head on attack missile you can see, but its dish size rather limits the range at which it can 'see' a target ahead, though illumination is not a function of dish size is it?

Tail position is interesting, it might be possible to relocate the tail down onto the fusilage in the manner of the F4 and Jaguar. If the rocket motor is dropped after 1960 (two years before ISD as projected I seem to reccal) then weight and volume is available for the transition.

Endurance on jet fuel along using HTP tankage for jet fuel as per Norman Friedmans book British Carrier Aviation is 2 hours and a loitering aircraft with rocket fuel is said to be able to intercept a target at 180nm. Presumably thats the "extended sortie" configuration with drop tanks or the use of IFR.
Both figures, 90nm and 180nm are relvent to the Type 984 radar and CDS used by the RN.

Additional added as my memory and reading allow.
Top speed on turbojet at sea level was projected at Mach 0.97.

 

[F-14D]

1952-55: what a time to be in aero design! Korean War, seen as prelude to incursion into W.Germany, stimulated spend. US/UK funded almost anything that seemed to offer quality v.WarPac quantity. Even schemes at minnows unable to build in quantity. So to protect sales of their rocket motors DH bought 33% Saro equity when they won P.177. SR177 would have been led at Cowes, built at (DH, ex-Airspeed) Christchurch, and flown from Hurn.

Deletion was due to: 1. general Defence funding cutback when USSR showed signs of sanity after Stalin; 2. RR solving reheat such as to put P1B (Lightning) close enough to where SR177 would be; 3. US funding the NATO Hawk SAM belt, embracing N.Norway, to cull high incoming Sov bombers before entering any UK defences. UK did not need to take on this expense. P1B only survived because its order, 20 DB plus 50 F.1, preceded new PM Macmillan hunting for economies and was presented as irrevocably committed past-the-point of savings.

Not to mention the infamous Duncan Sandys "White Papaer" of 1957 which declared there was no further need for manned aircraft and cancelled all RAF developments except for the Lightning which was, "...unfortunately too far along to cancel".

 

[F-14D]

One other thing rockets offered was tremendous thrust at high altitudes. A jet produces less and less thrust as altitude increases, falling to less than 10% of its rated thrust at higher altitudes. However, since drag is also so much less up there, that lower thrust is all that is needed. A rocket would produce less thrust, but it doesn't decrease as altitude increases. So, although it may only offer a fraction of the power of the jet at sea level, at altitude it has an effect equal to adding two or three more engines without the weight.

Among other aircraft for which a rocket was proposed (although not implemented) were the F8U-3, the F-15 and the F-20.

 

[overscan (PaulMM)]

Saunders-Roe SR.177 German version with IFR probe and Sidewinders. Also 3 view of the ground attack / recce version with rocket engine deleted, wingtip rocket pods plus ground attack loadout pics.

 

[Spark]

Saunders-Roe SR.177 German version with IFR probe and Sidewinders. Also 3 view of the ground attack / recce version with rocket engine deleted, wingtip rocket pods plus ground attack loadout pics.

Hi Zen

…………Curious question is why there was no serious canard design for an RN fighter in this period!.......…

There was; the Avro 720 wind tunnel model was tested with a foreplane in support of Avro’s proposal for a RN fighter with this configuration. Have not seen any drawings of such but was told about this development by the original Avro 720’s chief designer.
By the time of this development someone else had taken over but I believe it was the final development of the Avro 728? with a change over to HTP.
The only published drawings of which show a conventional delta. Would be very interested if someone could find any of the canard drawings.

To return to the SR177 I think they were also looking at a better wing and new materials but was told by a senior member of the design team that the aircraft was over weight.

Has any one any details of the SR177 variant that was to be launched from the back of a Avro Vulcan carrier aircraft in a similar fashion to that proposed for the Avro 720 and Vulcan or the SR53 from the Valiant?

 

[zen]

The most likely machine with a canard for the RN would've been EE's P6D study but this was under prompting from the ministery, as they thought a single RB.106 in a scaled Lightning type design would meet the ER requirement.

Would be interested to see this Avro design with canards...

Certainly a canard could solve some problems, but it produces others like obstruction of visibility.

 

[Jemiba]

From Tagg/Wheeler "From Sea To Air", an artist impression of the SR.177
in german colours. The nose seems to be less pointed, than in other drawings,
but I don't know, if this is just an error in the artistic representation, or an
indication of another type of radar.

 

[overscan (PaulMM)]

Here's the radar diagram. Type is not identified in this publication, its referred to as a lightweight single seat AI radar.

 

[TinWing]

Saunders-Roe SR.177 German version with IFR probe and Sidewinders. Also 3 view of the ground attack / recce version with rocket engine deleted, wingtip rocket pods plus ground attack loadout pics.

I always knew the brochure existed, but I never thought I'd actually see it. Thank you.

Overall, it seems a pity that the Gryon largely failed because of project cancellation, because it did seem like a plausible alternative to the J-75. I won't defend the rocket powered variant, but the conventional Gyron variant was plausible for the era. Of course, the Starfighter would succeed in sales for some very obvious reasons, many relating to a later scandal, and overall, the F-104 was admirable in manufacturing concept, although less so in operational use.

 

[Jemiba]

"...relating to a later scandal,.." , ".. although less so in operational use."

well, maybe the methods used by Lockheed to promote their design were a little
bit overstretched, but I think, by no means unusual in the world of military procurement.
And the problems that arose were mainly concentrated in the german airforce, which
directly went from the F-86 to the F-104, which, with regards to performance, but
also to flying characteristics and demands on the pilot, really was a quantum leap.

So, at least in the last point the SR.177 probably wouldn't have done much better.

 

[overscan (PaulMM)]

Saunders-Roe's SR.177 was hardly a multirole fighter, given that conversion to the strike/recce version involved removal of the rocket engine (replaced by a turbine APU) and conversion of the rocket fuel tanks to kerosene.

I think the model posted by Jemiba is the earlier proposal, retaining Red Tops. The drawings I posted are from later, with the use of Sidewinders and promotion of the strike secondary role.

 

[overscan (PaulMM)]

2 more pics

 

[Rickshaw]

"...relating to a later scandal,.." , ".. although less so in operational use."

well, maybe the methods used by Lockheed to promote their design were a little
bit overstretched, but I think, by no means unusual in the world of military procurement.
And the problems that arose were mainly concentrated in the german airforce, which
directly went from the F-86 to the F-104, which, with regards to performance, but
also to flying characteristics and demands on the pilot, really was a quantum leap.

So, at least in the last point the SR.177 probably wouldn't have done much better.

I've often also wondered about the problems of fuel handling. Liquid rocket fuels tend to be, shall we say, a bit more "energetic" than AVTUR. They also tend to be less forgiving of carelessness. I wonder what the accident rate on airfields where such aircraft were used, particularly in wartime would have been like. While the SR.177 and similar aircraft might have been just as unforgiving as the F-104 was in the air, they might have been a lot worse on the ground.

 

[Jemiba]

".. they might have been a lot worse on the ground."

Maybe comparable to the rate of fuel related accidents, the Me 163
encountered during her service career. And AFAIK, the second prototype
of the SR.53 ended in a fatal explosion, too, killing its pilot !

 

[alertken]

Little Saro remained locked in 1952, when UK had problems with afterburning/longevity of big turbojet hot sections, and with putting manoevrability in GW. Avro 720 and (SR.53 onway to) SR.177 were to solve those issues, for hi-altitude interception, by rocket boost, "cobra"-style upward lunge to release a straight-line AAM. The target was not the incoming platforms, which were to be scattered by longer-range, loiter Javelins, then F.155T, and long range, even nuclear-tipped big-Bloodhounds, but their ASM warheads. All, very UK-centric forward of Leuchars, not of great interest to, say, FRG.

SR.53 ITP was 9/55 ($1.5Mn. from MWDP). DH took 33.3% of Saro in 9/56, to protect Spectre and to impose Gyron in SR.177. ex-Airspeed Christchurch would have assembled, flight test from Hurn. Exactly in that timescale RR made reheat work on Avon, so in 11/56 50 (to be) Lightning F.1 were ordered, notions of belly Scorpion rocket-pack lapsed, Firestreak Mk.1 might jink, and Mk.4 (to be Red Top) might work head-on. So, in April,1957 Sandys junked F.155T et al. Persevering with SR.177, probably not rocket-confused, for FRG and Japan was more in hope than expectation, and funds were cut off in December,1957.

Avro 720 was chopped in 1956 as its liquids were seen as even more impractical than SR.177's. If we had more confidence in RR's reheat and DH's AAM control skills, we would have chopped SR.53/177 then, but we were in despair: Thin-Wing Javelin was chopped 31/5/56 to give some hope that even Mk.4 Dragmaster could be made to work. By 1959 we knew we had done good, as Blue Steel Mk.1 showed the problems of deploying HTP. All later ASM schemes were solid-fuelled.

 

[zen]

Brilliant, just lost my post, do I really want to try typing that out again?

So since it was a timeout lets try to type quickly and keep it brief then.

Lets see HTP is fine, fires can be put out with water, don't get it on the skin. Storage in pure aluminium tanks was the solution to its corrosive effect on carbon. HMS Eagle's refit had such tanks in the planning stages.

Radar, someone else has AI.23 data, so they can say whether that looks like AI.23.
Most say it was to be AI.23, but my Friedman says AI.20, maybe due to the date of RN documents he's read.

Stern chase was all Firestreak could give, P177 was to turn onto the tail of the target for a lock on.

Aircraft was an extension of SAM missile defences, RN particularly lacked a system for tacking down a bomber at 60nm from DLI or 90nm or more by CAP directed by AEW. P177 was the solution and SAM's where not considered valid a replacement even as the Defence Review concluded such.

Canceled in 57, but the US concluded stern chase is not going to work in 59. Do they tell anyone?

 

[Petrus]

Do you know how many rockets (and of what type) the wing-tip "rocket-battery" would carry?

Best regards,
Piotr

 

[robunos]

the second prototype of the SR.53 ended in a fatal explosion, too, killing its pilot !

According to several sources, including Putnam's 'Saunders and Saro', Gunston's 'Fighters of the Fifties'' and 'From Sea to Air', state that the aircraft failed to take off, hitting a concrete lighting pole, and exploding.
Officially the cause of the crash has never been explained, investigators finding no fault with the aircraft.
However, a footnote in 'Project Cancelled', page 47, states:-
'one suggestion [for the crash] was that the instrument panel became unlatched and fell onto the pilot's lap at a critical point in the take-off.'

cheers,
Robin.

 

[Jemiba]

The highly volatile rocket fuel may not have been the primary reason for the crash,
as it wasn't for many crashes of the Me 163, but it probably often made such crashes
unsurvivable, whereas without, the pilot may have been able to walk away !

 

[zen]

High Test Peroxide would'nt explode or even burn that much without contact to the catalyst. Its far safer than the sort of reactants the Germans where using in WWII.

Its greatest danger is drip feed onto a metal that catalises it down to oxigen Hydrogen and water in a confined space, such as happened with the RNs HTP torpedo back in the 50's and probably the Kursk too.
If there was a leak in the plumbing or the tank in the plane that fed onto a catalitic material for the chemical then it could prove lethal.

Hydrogen peroxide freezes at minus 5 and boils at 150 degrees C so its nothing like as problematic as liquid oxigen.

HTP was pumped through none-catalising metals to a catalist (silver gauze) after which it broke down to its constituents as it flowed a couple of inches further on. The reaction is energentic so it heats up and can be used alone as a rocket, where it helps to provide a spark for the energetic recombination of the oxigen and hydrogen.
But in the Spectre rocket motor its as its in this hot steam/oxigen hydrogen gas that the Kerosene vapour is injected with dramatic results.

 

[Orionblamblam]

High Test Peroxide would'nt explode or even burn that much without contact to the catalyst. Its far safer than the sort of reactants the Germans where using in WWII.

Ummm... H2O2 will react violently with a lot of things. Rust, for instance. Many other oxides. Leather. Skin. Sweat. Wood. Dirt. Bugs. Blood makes it go *insane.*

Its greatest danger is drip feed onto a metal that catalises it down to oxigen Hydrogen and water in a confined space...

H2O2 breaks down into water and *oxygen,* plus a boatload of *heat.* H2O2 => H2O + O2 + heat.