uk 75

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Taken at the De havilland Aviation Heritage Museum, suspended near a Gyron engine adjacent to the gift shop.
This model is a modern one probably made in the Philippines like some in my collection..You can tell by the squadron marking, 60s livery and the black lining. It may well be available from the Gift Shop..
If you compare it with the original period model shoen on itd stand you will see what I mean.
 

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Some of the earlier posts speculated that the SR 177 would possibly have been able to operate from a modernised Colossus or Majestic light fleet carrier. If this was the case then the type continuing development through to deployment may have changed the opinion that the light fleet carriers would need to be replaced as they were too small for the incoming designs, i.e. Sea Vixen and Scimitar. SR 177 could have been a very interesting alternative allowing said ships to potentially serve into the 80s.
There was somewhere on this site s pdf concerning wind tunnel tests of the Saro F.177 design examining it's low speed characteristics and schemes for reducing it's TO&L speeds.
Essentially it's speeds are with blow over the wing, not far off the Scimitar. But obviously at lower weights.
The result is a modified Colossus or Majestic might operate it safely.
But it all comes down to those modifications.
Where it would really tell is on a Centaur.
Obviously a wingfold would help.
 

Volkodav

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Some of the earlier posts speculated that the SR 177 would possibly have been able to operate from a modernised Colossus or Majestic light fleet carrier. If this was the case then the type continuing development through to deployment may have changed the opinion that the light fleet carriers would need to be replaced as they were too small for the incoming designs, i.e. Sea Vixen and Scimitar. SR 177 could have been a very interesting alternative allowing said ships to potentially serve into the 80s.
There was somewhere on this site s pdf concerning wind tunnel tests of the Saro F.177 design examining it's low speed characteristics and schemes for reducing it's TO&L speeds.
Essentially it's speeds are with blow over the wing, not far off the Scimitar. But obviously at lower weights.
The result is a modified Colossus or Majestic might operate it safely.
But it all comes down to those modifications.
Where it would really tell is on a Centaur.
Obviously a wingfold would help.
A fully developed SR177 could have made light carriers viable for much longer, especially if a suitable complementary carrier capable MPA was developed as well, one with a reasonable secondary anti ship or even strike capability.
 

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I may be mis-remembering and would have to dig-out Friedman to confirm, but I think Hermes was planned for P.177 and would have received HTP storage.
 

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Certainly Eagle and Victorious had planned airwings with F.177s in place of Scimitars. So I wouldn't be surprised if there was something similar for Hermes.
It also explains why the Scimitar was being used as the metric for the Trade Protection Carrier 'Argument' between DNC and DAW. As if you can operate Scimitar, you can operate F.177.
 

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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.

A true blast from the past here, apologies Overscan.

Looking at SR177 plan views, and comparing them to EE Lightning, there firstly does not seem to be any appreciable area ruling on the Lightning. Secondly, the SR177 does appear to have a slightly curved notch in the fuselage where the wing joins - but nothing on the scale of the F-102.

Now maybe I’m wrong on the Lightning, perhaps there is some subtle area ruling, or maybe the configuration is not as susceptible to transonic drag - but from an admittedly brief look at things, if nothing precludes the Lightning from going supersonic, can we say the 177 cannot?
 

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I've never noticed the different air intake before, I've always seen it with the single intake with the 'shock cone', not the divided one show on the models. Was this an actual development or was it a bit of poetic license by the model maker.

Also images of the naval version with a carrier always show a light fleet carrier.

As a matter of interest, how was it planned to deploy the RAF version. I seem to recall; from a dark and dusty corner of my memory, that it was intended for them to take of from from a 'zero length' launcher, much like the experiments undertaken in the US with Super Sabres and Starfighter.
 

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Apologies for cross-posting but never seen this before so its a new revelation to me.
Tony Wilson's English Electric Lightning: Genesis & Projects mentions that in May 1956 the MoS were considering arming the Saro P.177 with Sparrow II to overcome Blue Jay's poor weather limitations. Ferranti were asked if they could add CW injection into the AI.23.
Presumably this was a short-lived musing given the status of the Sparrow II programme.
 

overscan (PaulMM)

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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.

A true blast from the past here, apologies Overscan.

Looking at SR177 plan views, and comparing them to EE Lightning, there firstly does not seem to be any appreciable area ruling on the Lightning. Secondly, the SR177 does appear to have a slightly curved notch in the fuselage where the wing joins - but nothing on the scale of the F-102.

Now maybe I’m wrong on the Lightning, perhaps there is some subtle area ruling, or maybe the configuration is not as susceptible to transonic drag - but from an admittedly brief look at things, if nothing precludes the Lightning from going supersonic, can we say the 177 cannot?
Lightning (P1B) actually was area ruled, largely accidentally. The wing shape helped avoid the fat middle of the early deltas. There's a drawing (in a Flight article I think?) showing the area profile and it's pretty good.
 

overscan (PaulMM)

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Apologies for cross-posting but never seen this before so its a new revelation to me.
Tony Wilson's English Electric Lightning: Genesis & Projects mentions that in May 1956 the MoS were considering arming the Saro P.177 with Sparrow II to overcome Blue Jay's poor weather limitations. Ferranti were asked if they could add CW injection into the AI.23.
Presumably this was a short-lived musing given the status of the Sparrow II programme.

From my P.1121 book -

Drawings of P.1103 with American Sparrow
weapons were produced in 1955. The
Hawker drawings seem to show how the general
shape of the AAM-N-2 Sparrow I, but the
intended model appears to have been the
AAM-N-3 Sparrow II, while Ralph Hooper’s
notes seem to have mixed up Sparrow II and
Sparrow III in terms of which version had
active radar homing.

The Sparrow II doesn't need a CW illuminator as it has its own radar, so it seems likely that they were actually intending to fit Sparrow III with SARH homing. AI 23 with CW illuminator added crops up in various programs in this timeframe.

It seems that there was a lot of confusion about Sparrow versions at the time, as Ralph Hooper's notes on Sparrow definitely have II and III the wrong way around.
 

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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.

A true blast from the past here, apologies Overscan.

Looking at SR177 plan views, and comparing them to EE Lightning, there firstly does not seem to be any appreciable area ruling on the Lightning. Secondly, the SR177 does appear to have a slightly curved notch in the fuselage where the wing joins - but nothing on the scale of the F-102.

Now maybe I’m wrong on the Lightning, perhaps there is some subtle area ruling, or maybe the configuration is not as susceptible to transonic drag - but from an admittedly brief look at things, if nothing precludes the Lightning from going supersonic, can we say the 177 cannot?
Lightning (P1B) actually was area ruled, largely accidentally. The wing shape helped avoid the fat middle of the early deltas. There's a drawing (in a Flight article I think?) showing the area profile and it's pretty good.
Cheers Overscan, I’ll have to hunt for that article. I wonder if there’s any area data for the SR177?
 

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Let's add in that study about fleet defence here.
It had a piece about head on collision course AAM substantially improving the distance at which an intercept could happen. Plus the simplicity of head on intercept compared to stern chase for computing the optimum.

Arguably Sparrow II is the stronger case due to it's ARH seeker.
As it was an 18" dish AI set would have quite limited range against a target. So Sparrow III would impose quite a demand on the pilot due to the shorter range of radar detection and tracking. Time from detection to missile launch would be tight for head on intercept.
But Sparrow II although shorter ranged is potentially more automatic.
 

uk 75

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A lot of wishful thinking here. I doubt whether Saunders Roe were in the position to redesign the Sr177 in the way you suggest, still less manufacture them.
If the RN had wanted to use the Colossus/Majestics as trade protection/ASW carriers into the 60s the A4 Skyhawk would have been a much more realistic choice as Australia did.
But the resources were needed for the big fleet carriers culminating in CVA01.
 
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Hood

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From my P.1121 book -

Drawings of P.1103 with American Sparrow
weapons were produced in 1955. The
Hawker drawings seem to show how the general
shape of the AAM-N-2 Sparrow I, but the
intended model appears to have been the
AAM-N-3 Sparrow II, while Ralph Hooper’s
notes seem to have mixed up Sparrow II and
Sparrow III in terms of which version had
active radar homing.

The Sparrow II doesn't need a CW illuminator as it has its own radar, so it seems likely that they were actually intending to fit Sparrow III with SARH homing. AI 23 with CW illuminator added crops up in various programs in this timeframe.

It seems that there was a lot of confusion about Sparrow versions at the time, as Ralph Hooper's notes on Sparrow definitely have II and III the wrong way around.

Thanks, that makes more sense.
If anything Tony Wilson's book brings out the complete chaos reigning in the AAM field in Britain at the time, a whole multitude of missiles and sub-versions and tinkering that was largely wasted effort. So its no surprise getting a handle on US systems was difficult given the amount of paper work coming out of the MoS.

Regards area rule, the Lightning was analysed when Whitcomb's research was made public and found to be largely ok without the need for further bumps and bulges. Having the missiles where they were seemed to help too, in effect acting as a 'bulge' on the forward fuselage ahead of the wing. The slightly wider T.4 and T.5 canopy bulge made them marginally faster clean too. This was probably a lucky break, though its noticable that some of the later PL configurations with the largest belly pods had rear bulges added for fuel tanks which was probably to overcome the greater cross section of the extensive ventral pod and match the advantages the wider T.5 forward bump gave.
 
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Some of the earlier posts speculated that the SR 177 would possibly have been able to operate from a modernised Colossus or Majestic light fleet carrier. If this was the case then the type continuing development through to deployment may have changed the opinion that the light fleet carriers would need to be replaced as they were too small for the incoming designs, i.e. Sea Vixen and Scimitar. SR 177 could have been a very interesting alternative allowing said ships to potentially serve into the 80s.

Is that related to the rocket in the back ? (big thrust)
- because mixed mode fighters (rocket + jets) weren't very practical in the long term.
HTP on a ship wasn't very practical...
 

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The mixed rocket-jet propulsion may not seem very sensible in hindsight, but it was attractive enough to be pretty widely considered. Even the Mirage III design included a rocket pack.

When the SR.177 was conceived, I think several factors made the rocket attractive:

* Early jet engines were comparatively slow to accelerate.

* Afterburners were in their infancy, and getting them to work safely, reliably, and relatively economically while providing worthwhile additional thrust took some time. Just compare the eyelid nozzles on an early Mirage to those on an F-16 to see how far things have come.

* The naval and air-force doctrine of the time prioritized interception of fast, high-altitude, nuclear-armed targets. Jet-fighter range and endurance were still relatively modest, so combat air patrol at long range was not practical. This put a premium on maximum rate of climb immediately after takeoff.

The SR.177 was, if anything, a fairly conservative application of the mixed power idea. It's predecessor, the SR.53, was conceived as a light, short-range interceptor for the RAF, where the rocket was the main source of combat of combat power, as in the Me163. The Viper turbojet was intended mainly to allow post intercept recovery to a suitable airfield. A reusable SAM of sorts.

Finally, nasty as high-test hydrogen peroxide can be (I have seen the effect of smallish amounts on human flesh in the lab), would it really be any more dangerous and impractical aboard ship than the gasoline that navies had accepted for decades?
 

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Area Rule Chart by Lightning Aerodynamicist Ray Creasey

In reply to several posts about area rule in this thread and others, this chart by Lightning aerodynamicist Ray Creasey does the best job of showing the difference in cross sections between a non area ruled aircraft and an area ruled one. It seems the mistake most make about whether a configuration has been area ruled is to look only at the fuselage and ignore the wings, tail surfaces, and other bodies apart from the fuselage. The graphs of areas at the bottom of the chart show that the fuselage is just a part of the overall cross section of the aircraft.

This chart is from page 73 of the just published English Electric Lightning-Genesis and Projects by Tony Wilson.
 

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SeaslugMk2

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Area Rule Chart by Lightning Aerodynamicist Ray Creasey

In reply to several posts about area rule in this thread and others, this chart by Lightning aerodynamicist Ray Creasey does the best job of showing the difference in cross sections between a non area ruled aircraft and an area ruled one. It seems the mistake most make about whether a configuration has been area ruled is to look only at the fuselage and ignore the wings, tail surfaces, and other bodies apart from the fuselage. The graphs of areas at the bottom of the chart show that the fuselage is just a part of the overall cross section of the aircraft.

This chart is from page 73 of the just published English Electric Lightning-Genesis and Projects by Tony Wilson.
You also have to subtract the area of the air ducts, with a correction depending on the velocity of the air when in supersonic flight.

SRJ.
 

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Some of the earlier posts speculated that the SR 177 would possibly have been able to operate from a modernised Colossus or Majestic light fleet carrier. If this was the case then the type continuing development through to deployment may have changed the opinion that the light fleet carriers would need to be replaced as they were too small for the incoming designs, i.e. Sea Vixen and Scimitar. SR 177 could have been a very interesting alternative allowing said ships to potentially serve into the 80s.
There was somewhere on this site s pdf concerning wind tunnel tests of the Saro F.177 design examining it's low speed characteristics and schemes for reducing it's TO&L speeds.
Essentially it's speeds are with blow over the wing, not far off the Scimitar. But obviously at lower weights.
The result is a modified Colossus or Majestic might operate it safely.
But it all comes down to those modifications.
Where it would really tell is on a Centaur.
Obviously a wingfold would help.
A fully developed SR177 could have made light carriers viable for much longer, especially if a suitable complementary carrier capable MPA was developed as well, one with a reasonable secondary anti ship or even strike capability.

Majestic class carriers were sold to Argentina, Australia, Brazil, Canada, Holland, India, etc.
The last one was broken up - in India - in 2014. Several navies concluded that Panthers were too big, but a few did fly A-4 Skyhawks from their Majestic-class decks ... often up-dated with angled flight decks.
 

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Majestic class carriers were sold to Argentina, Australia, Brazil, Canada, Holland, India, etc.
The last one was broken up - in India - in 2014. Several navies concluded that Panthers were too big, but a few did fly A-4 Skyhawks from their Majestic-class decks ... often up-dated with angled flight decks.

Independencia and Veinticinco de Mayo were both Colossus Class carriers, but what you've stated applies. Argentina bought F9Fs for Independencia but its catapult system was not powerful enough and the F9Fs remained landbound until their retirement and Independencia's complement was piston-engined aircraft only, F4Us, T-6s, T-28s and Grumman Trackers.

The Veinticinco de Mayo, as you know operated A-4s. The Royal Australian Navy had issues with its Majestic Class carrier HMAS Melbourne and its catapult initially when operating A-4s and lost a few as a result.
 

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Zoo Tycoon

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Independencia and Veinticinco de Mayo were both Colossus Class carriers, but what you've stated applies. Argentina bought F9Fs for Independencia but its catapult system was not powerful enough and the F9Fs remained landbound until their retirement and Independencia's complement was piston-engined aircraft only, F4Us, T-6s, T-28s and Grumman Trackers.
Operations did occur but were limited in terms of range and payload.

Independencia is reported to have rarely made it out to sea and was fairly quickly wrecked (run aground) by a captain who was drunk whilst in charge.

It was said to have been afflicted by a witches curse on the way back from its Christmas Island adventure (HMS Warrior), ref Christmas Island Cracker by Oultan.
 

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Great spot, these pictures are very rare. I was once told by a former SR employee that after cancellation, and in response to interest from Japan, the sections of SR177 produced were arranged on trestles to represent the finished aircraft.

It’s also interesting that this picture;-


shows three SR53’s fuselage’s in construction, presumably one is for static test.
 

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Independencia is reported to have rarely made it out to sea and was fairly quickly wrecked (run aground) by a captain who was drunk whilst in charge.

It was said to have been afflicted by a witches curse on the way back from its Christmas Island adventure (HMS Warrior), ref Christmas Island Cracker by Oultan.

Egads!
 

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I've never seen the second inlet shape before. The original intake had a movable lip which had to be in the forward position to allow the nose gear to deploy, IIRC. The second shape would remove that requirement.
Hi! My understanding about SR.177 original air intake is as follows. Complicated shape.
 

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I've never seen the second inlet shape before. The original intake had a movable lip which had to be in the forward position to allow the nose gear to deploy, IIRC. The second shape would remove that requirement.
Hi! My understanding about SR.177 original air intake is as follows. Complicated shape.
That's one ugly sucker!
 

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The mixed rocket-jet propulsion may not seem very sensible in hindsight, but it was attractive enough to be pretty widely considered. Even the Mirage III design included a rocket pack.

When the SR.177 was conceived, I think several factors made the rocket attractive:

* Early jet engines were comparatively slow to accelerate.

* Afterburners were in their infancy, and getting them to work safely, reliably, and relatively economically while providing worthwhile additional thrust took some time. Just compare the eyelid nozzles on an early Mirage to those on an F-16 to see how far things have come.

* The naval and air-force doctrine of the time prioritized interception of fast, high-altitude, nuclear-armed targets. Jet-fighter range and endurance were still relatively modest, so combat air patrol at long range was not practical. This put a premium on maximum rate of climb immediately after takeoff.
Rockets have several significant advantages:
  1. Their thrust doesn't lapse away at high altitude.
    • A typical first-order approximation for a jet would be to assume thrust proportional to δ/√θ. This effectively says that the specific thrust is constant and the axial Mach number at the compressor face is fixed, which is reasonable provided that T20 doesn't get unreasonably high.
  2. They don't run out of T30 margin at high Mach number.
  3. They don't have intake momentum drag.
    • In the context of a mixed power aircraft with a supersonic dash capability, this can greatly simplify the intake design, because high pressure recovery at high MN is not required. This can save quite a lot of weight (as later demonstrated by F-16).
Taken together, these factors can make a relatively small rocket quite compelling near the top-right corner of the flight envelope.

AltitudeMach Numberδ (total)θ (total)Non-dimenional thrustJet thrustTotal thrust
(rocket = 10,000 lbf)
Jet thrust as a proportion of total thrust
0 km0.01.00001.0000100%14,000 lbf24,000 lbf58%
0 km0.81.52431.1280144%20,160 lbf30,160 lbf67%
0 km1.22.42501.2880214%29,960 lbf39,960 lbf75%
11 km0.80.34150.848637%5,180 lbf15,180 lbf34%
11 km1.20.54330.969055%7,700 lbf17,700 lbf44%
11 km1.60.95221.137589%12,460 lbf22,460 lbf55%
11 km2.01.75291.3541151%21,140 lbf31,140 lbf68%
20 km0.80.08320.84819%1,260 lbf11,260 lbf11%
20 km1.20.13230.968413%1,820 lbf11,820 lbf15%
20 km1.60.23191.136822%3,080 lbf13,080 lbf24%
20 km2.00.42701.353437%5,180 lbf15,180 lbf34%

This very simple model is optimistic in its jet thrust prediction at higher Mach numbers, because it implies perfect intake pressure recovery, and no T30 limit. It also neglects the increase in rocket thrust with altitude due to reduced ambient pressure increasing the pressure thrust term.

Despite this, the rocket is the dominant source of thrust at altitude.
The SR.177 was, if anything, a fairly conservative application of the mixed power idea. It's predecessor, the SR.53, was conceived as a light, short-range interceptor for the RAF, where the rocket was the main source of combat of combat power, as in the Me163. The Viper turbojet was intended mainly to allow post intercept recovery to a suitable airfield. A reusable SAM of sorts.
As you can see from the sample calculations above, the lapse behaviour of the jet engine means that the rocket is the dominant source of thrust at high altitude. However, what matters in the interception business is the ability to gain total specific energy. For a slow aircraft, this is basically synonymous with height, but for a supersonic aircraft the kinetic energy term becomes significant.

An aircraft flying at Mach 2 and 11 km on a standard day is flying at about 590 m/s TAS. This is equivalent to about 17.75 km of energy height, so the majority of its energy is kinetic rather than potential.

From an energy perspective, what matters is (specific excess) power, i.e. the rate of doing work. This is the product of thrust and velocity, and therefore a rocket does no useful work on a static vehicle. The mixed power fighter is more attractive than the pure rocket because its jet engine has a much better TSFC and can allow the rocket to be reserved for use at high velocities when it is more effective at rapidly increasing the energy state of the vehicle.

Mixed power interceptors are perfectly sensible, and can reasonably be expected to out-perform jets if high altitudes are required, provided that the duration of the rocket burn is fairly short. This is because the thrust-to-weight ratio of the rocket is much better than that of the jet, especially at altitude.

E.g. a Spectre is about 430 lbm, so the thrust-to-weight ratio of the engine itself was about 20. The ISP was about 200 seconds, so the TSFC was about 18 lbm/lbf/hr.

However, the Gyron Junior only has a static thrust-to-weight ratio of about 4.5 with reheat at sea level (referenced to the dry engine weight, i.e. excluding any supersonic intake).

If we consider the Mach 2.0 / 20 km case, the TSFC of the jet is probably about 2.0 with reheat. The thrust-to-weight ratio under these conditions is only 37% of the number we first thought of, so about 1.7.

We may now compare the jet and the rocket, using a "rubber" jet engine:

Duration (minutes)Weight of jet scaled to 10,000 lbfMass of jet fuelTotal weight for JetWeight of rocket + fuel for 10,000 lbfMass of rocket propellantTotal weight for Rocket
05985 lbm333 lbm/minute430 lbm3,000 lb/min
1..333 lbm6,318 lb..3,000 lbm3,430 lbm
2..666 lbm6,651 lb..6,000 lbm6,430 lbm
3..1000 lbm6,985 lb..9,000 lbm9,430 lbm

The rocket is much lighter than the jet, provided that the thrust duration at high altitude is short.

In reality, the total weight of the jet system would be rather heavier than this due to the intake system, and this would tend to increase the cross-over duration.

Because the jet makes less thrust at lower speeds for want of intake ram, the cross-over duration would be significantly longer if subsonic manoeuvre or transonic acceleration were considered.

Also, because in-flight-refuelling would be unlikely to replenish oxidizer, it is probably attractive to over-size the oxidizer capacity somewhat in order to improve combat persistence, so the 7 minutes of rocket endurance quoted for SR.177 is pretty reasonable.

Modern engines have higher thrust-to-weight ratios, and might be expected to double those available to the SR.177. Specific impulse hasn't really improved much, so the optimum rocket duration would probably be less today.

The main reason for the demise of the mixed power interceptor was the demise of the high altitude supersonic bomber, which left it bereft of targets. However, if the optimists are correct in forecasting a proliferation of supersonic business jets in the next few decades, it may be that there is a renewed interest in very high performance manned interceptor aircraft, and in that case the mixed power concept would be worth revisiting.
Finally, nasty as high-test hydrogen peroxide can be (I have seen the effect of smallish amounts on human flesh in the lab), would it really be any more dangerous and impractical aboard ship than the gasoline that navies had accepted for decades?
HTP demands respect, but the traditional way to make it safe is to dilute it with water, which is readily available at sea. It is also pretty dense, so the volume to be stored and protected is fairly small. I think it's a pretty reasonable liquid oxidizer when compared with the alternatives.
 

blackkite

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According to BRITISH EXPERIMENTAL TUEBOJET AIRCRAFT,Barry Jones, CROWOOD AVIATION SERIES, Page 198,

"A conical, fixed centre-body occupied the top portion of the intake, which had the first 15in(40cm) of its lip able to slide forward when the undercarriage was lowered, to allow for the engine's pressure recovery at landing speed, and sliding back to the in-flight position once the wheels had been retracted. "
 

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NMaude

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According to BRITISH EXPERIMENTAL TUEBOJET AIRCRAFT,Barry Jones, CROWOOD AVIATION SERIES, Page 198,

"A conical, fixed centre-body occupied the top portion of the intake, which had the first 15in(40cm) of its lip able to slide forward when the undercarriage was lowered, to allow for the engine's pressure recovery at landing speed, and sliding back to the in-flight position once the wheels had been retracted. "
IIRC this fact was mentioned in a 1994 Aeroplane magazine article on the SR.177.
 

Hood

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"The intake, which is part of the aircraft, features a two shock cone and a cowl which slides forward to open up a secondary intake slot for low speed operation. Boundary layer air from the nosecone above the intake is captured by a duct and used to supply cooling air to some systems."

A diagram also states it was actuated into this position when the undercarriage is selected 'down'.

From, the article 'The SR.177 High Altitude Interceptor', by D. Hardy in Space Chronicle, UK Manned Rocket Aircraft (JBIS, Vol. 55, Suppl. 2)

In fact there is a fairly well known artists impression of a P.117N coming into land which clearly shows the extended intake lip.
 

zen

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Also, because in-flight-refuelling would be unlikely to replenish oxidizer, it is probably attractive to over-size the oxidizer capacity somewhat in order to improve combat persistence, so the 7 minutes of rocket endurance quoted for SR.177 is pretty reasonable.
7 minutes at full power so i reccal but throttle-able down to 10% thrust. Potentially providing a theoretical endurance of 70 minutes.

However it's Saro's own interception flight profile that shows the reality.
Reheat for TO and rapid climb, unreheated for throttled back loiter to position for intercept.
Then reheat at rocket for hard climb and acceleration.
Cut rocket for final positioning.
Presumably lock-on and then rocket on, hard turn keeping target lock-on followed by stern engagement with missiles....or until rocket runs out of fuel.
Then cut reheat and throttle back for powered glide to carrier recovery orbit.
 

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I have a question concerning the uncompleted SR-177 prototypes, after that fool Duncan Sandys cancelled them in his idiotic 1957 defence white-paper what happened to them? I ask because after the Hawker P.1121 was cancelled the nearly structurally complete prototype wasn't scrapped it was stuck in a warehouse and ended up at RAF Cosford, now did something similar happen to the SR-177 prototypes or were they ignominiously scrapped?
 

Archibald

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HTP demands respect, but the traditional way to make it safe is to dilute it with water, which is readily available at sea. It is also pretty dense, so the volume to be stored and protected is fairly small. I think it's a pretty reasonable liquid oxidizer when compared with the alternatives.
How did I missed that brilliant post back then ? d'oh !

The annoying thing with rockets (as far as mixed rocketplanes are concerned) is that
a) the oxidizers are too few
and
b) they are all flawed, one way or another.
- fluorine is demonic stuff
- liquid oxygen is way too cold, -183°C
- HTP tends to explose only with minor impurities spoiling it
- N2O performance sucks
- N2O4 is toxic, carcinogenic, corrosive and so are all the close derivatives also storables.

And basta - there is nothing else.
 
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