Robert HiltonAnd what were your results?
I think a stronger engine make sense in some respects, even more so when the turbo-jet is replaced by a more fuel efficient engine of current technology. The gain in speed is low and may even be negative in some areas, but lower fuel burn can be achieved. The surplus power helps under some conditions. Fact is that thrust today comes at a much lower weight price than in the J79-times.
Well RR did in fact offer the RB 168 (Spey) with reheat as an alternative for the J79 in the F104G. It would have been at least a more fuel efficient choice.
Robert HiltonSlip streaming past Mach 1 without afterburner isn’t real useful unless you can do two things, exceed the transonic drag barrier with your payload in tow and sustain the speed in a cruise configuration for a useful amount of time. I wouldn’t doubt a fully fuelled and even armed Lightning F.2A (btw – it was said to be more aerodynamic with the nose mounted missiles) could exceed Mach 1 on dry, but the dry thrust was probably unable to sustain a meaningful cruise configuration which means to sustain the greater than transonic speed it is hemorrhaging fuel.
You have to reach a point where your fuel burn off is more efficient in relationship to range than what is possible at the point of the transonic speeds. Don’t think of Mach 1 as the simple barrier, its more related to the shock cone generated as it passes through the sound barrier. The F-22 will use less fuel to sustain just over Mach 1.3 than it will at Mach .85 to Mach 1.25, which says a lot about its engineering.
That all sounds very well.
Slipstreaming, by that do you mean following the wake of another aircraft?
The reason a Lightning could not cruise any length of time was due to the lack of fuel capacity compared to the sfc of the engines. A Lightning typicallys goes fuel critical about three seconds after start up.
That the F22 uses less fuel at Mn 1.3 compared to 0.85-1.25 is nothing new. The high fuel consumption ( due to very high drag) has always been associated with the transsonic area. Try looking up Whitcomb and Kucheman or the area rule. Alternatively, look at the shape of all a/c that pass the transsonic area that have been built for the last 40 years. They don’t have that “coke bottle” shape for nothing.
Robert HiltonEngines performances? dry Max mean the eurofighter lose speed by his mass only, as simple as that, the TWR under 1 mean your mama will never pass Mach 1 without AB! and a supercruise isn’t a plane stoping his AB the Dry at Mach 2 to claim supercruise!
supercruise is sustaining on dry output supersonic speed ,over Mach 1, not going there somes times, its taking off, going to top level 60.000 feets and accelerating till going to Mach 1, when a TW ratio is under 1, the plane don’t have enough acceleration to pass supersonic speed , its just basic physic!
Then why could the BAC Lightning exceed Mn 1 without reheat?
It had slightly less thrust than weight (with reheat engaged), but it could still super cruise. It still can in South Africa.
Robert HiltonI have heard of aircraft with a T/W ratio of less than 1 supercruising under certain conditions. Aerodynamics are key.
The key is a combination of aerodynamics and engine/intake design.
Sticking a 50,000lb class fan engine (RB211 or such) into a fighter will not make it fast. A good example was the F4 Phantom II. The British version was fitted with RR Spey engines which had bags more power than the original J79s. Unfortunately, they were also larger in diameter which increased the frontal area of the a/c. Result, better acceleration with a slightly lower top-end.
As Concorde proved with the intake/engine configuration, static thrust is not as important as the thrust increase brought upon by it’s forward speed and how the intake converts it into an increased pressure ratio for the engine.
As most people know, you can tune a car engine ( to a certain degree) by increasing the compression ratio. This increases the thermal efficiency (heat turned into useable energy) of the engine. The same is true for the pressure ratio in a gas turbine engine. Increase the pr and you get more umph.
When flying at Mn 2.0, the variable geometry intakes on Concorde were delivering the air to the engine at a pr of 6:1. The compressor itself had a pr of 10:1. This gave the engine a total pr of 60:1 which gives it a very large thrust increase when compared to it’s nominal static thrust. So, SLS (sea level static) is not the be all of an engines performance, in fact thrust decreases when an aircraft accelerates for take off. It starts to recover somewhere around 300 kts and increases from there depending on intake type and shape. That is what is termed “ram recovery”, it is easily seen when you consider the basic calculation for thrust. In it’s most basic form T=M(V2-V1)
V1 being the forward speed of the a/c
V2 being the gas velocity from the thrust nozzle.
If the engine rpm remains the same during acceleration then we can assume the gas velocity is also constant, so the faster you go, the less the difference between gas stream and forward movement. Thus less thrust.
It isn’t a simple case of adding up weight/static thrust= fast, it doesn’t work that way.
Robert Hiltonlet’s prove it, i bring you basics aeronautic rules, and you the dreams from no where!
Prove it, i will bring you all aeronautics physics knowledges you need from the best universities datas bases on it around the world!
a plane that is under 1 on T/W ratio can’t physicly supercruise, supercruise isn’t reaching Mach 1, it’s sustaining supersonics speed along mission on dry THRUSH!
11.3t + half fuel 2.5t= 13.8t so with 12t Trush it makes 12/13.8 = 0.86 ratio
even rafale is better with more range!
9.2t + half fuel 2t= 11.2t with 10t trush it makes 10/11.2 = 0.89 ratioGet a life!
Don’t confuse the static thrust an engine delivers on the test bed with how it works in the a/c at speed. How much ram recovery does the intake produce and at what speeds?
Robert HiltonDiet coke all over the screen, Mr Hilton.
My apologies.
Robert HiltonOriginal Post-
“I have been loosely following the EF/Typhoon program for years now, and with all do respect to its supporters, I just don’t understand what is so awesome about this aircraft?
Well, you don’t need a chainsaw to open the canopy.
Robert HiltonHi Robert,
Yes, I guess they were all getting on in age. I joined the RAF on a Short Service Commission as a Pilot in ’52, failed to make the cut due to colour vision problems and was offered a Nav job in V Bombers, which were then approaching service and, since they had two navs, there was a big push on to train more navs. I declined as I did not like the idea of riding in the back seat without an ejection capability!
D.
As a tekkie I must say that was a wise choice. Never forget, HP built 32 mk2’s, 32 different ways! They all had their foibles when I worked on them, still you did have to work on them and not just replace bits.
Robert HiltonI was the “Air Boss” of the Hamilton show when the Victor crashed.
It created a major problem for the show as it’s tail impinged on the clearances on the main runway, the only one long enough to take some of the Military jets, which was then closed.
We could not move the aircraft until it had been examined and we had to turf out the Air Attache from Ottawa (Who had been invited to attend but was involved something else.) and he flew in and convened a Court of Inquiry. The CoI group flew in via a VC-10, which we hoped would stay for static display at the show, no such luck!
The bottom line was the aircraft was moved enough to allow the runway to re-open and the diverted aircraft were gathered in from the surrounding airfields. Fortunately the Victor had planned to come in early.
The Victor had flown in from Marham direct and we had requested that they bring a barrel of British beer to sell at the show. The Fire crew said when they got to the aircraft they were amazed to see the crew was pushing out a barrel of beer! Unfortunately the fire crew took the rescued flight crew to their building and somehow the beer never made it to the show!
What happened? According to the story we got from the crew,(before they had time to think a better one up) they had an electrical problem when between Quebec and Montreal and they had to cancel their IFR flight plan, so they descended to below the IFR level (9,500ft?) and flew VFR to Hamilton. This of course significantly increased the fuel consumption!
Unfortunately Hamilton is susceptible to local fogs as the warm moist air from the Lake Ontario drifts in and is pushed up over the airport where it condenses to form a local fog. We got the word from Toronto Control that the Victor was coming in and was going to attempt an approach without it’s approach aids!! The first approach was missed and we got word from the Hamilton tower that they only had sufficient fuel for one more approach and after that they were going to fly over Lake Ontario and eject!
They broke out of the crud to find they were significantly off the runway heading and they tried a quick correction, but they just did not have time to correct and they ran off the runway into a gully, driving the undercarriage oleos up through the wings.
It was our understanding that the aircraft was one of the newer Victors and it had recently had it’s life extended.
We were told the Captain was let go from the Air Force mainly for lack of judgement in that he could have landed safely at Montreal, Trenton or Toronto. The aircraft was scrapped and the nose section was donated to the Canadian Warplane Heritage Museum. I believe they eventually disposed of it as it did not fit into their collection mandate.
It was a long time ago, I hope this fills in some gaps.
Deryck
Hi Deryck,
Thanks for the story from the other side, it is indeed interesting to read.
As we were lead to believe at the time there were a fair number of contributary factors that lead to the crash. I had heard of the electrical problem, which was not uncommon at the time, there was also mention of the IFF equipment being incorrectly tuned for the flight.
Of course the desire to land at the correct airfield was also paramount.
As to the Captain being let go, I actually spoke with him in mid 1986 which was a fair while after the event and he was still active (although under a cloud).
Calling 191 a newer aircraft is abit on the positive side. A less old airframe would have been a better description, and it had indeed had a recent wing strengthening modification.
Robert HiltonPeter et al–
“Victor to the skies”…ah to dream. Never saw one fly. Certainly heard one, XL191 thundering over Hamilton in the absolute duff, a couple minutes from the end of her flying career, but couldn’t see a thing…
I’d posted earlier to ask about landing lights on a Victor and swiftly got the needed response–thanx gents; have now done the intended painting of old 191 coming at you through a curtain of rain, will post an image of it somewhere in due course. Peter–you’d asked specifically about the painting; once I have a digital image of it I’ll email it your way for interest’s sake…
Cheers
S.
That would be nice to see, I’ll keep an eye out for that.
Robert HiltonI wish they would take better care of her
I can’t really see what they can do to improve the a/c. It has already been gutted for spares recovery although it does have less FI than the other survivers. Might be a good project in a couple of years time. Victor to the skies?
Robert HiltonBy means of a goer do you mean scrap? would it have been kept on strength to replace 191 then?
Yes, XL192 was kept as replacement. Five other airframes were scrapped around the country (amongst them XH673) and all useable spares were removed to keep the rest flying.
Robert HiltonThe talk at the time was that the a/c was aligned with the wrong runway. At the last moment he corrected and and side-slipped in. According to legend at the time, the Crew-Chiefs last words before contact were “I don’t think you’re going to make it Sir.”
I met up with the Captain in at Edwards in ’86. I was there to fix his a/c, he was a little concerned for his career prospects at the time due to certain incidents during the detatchment and of course having smacked 191 in. I got the distinct impression from his own words that some form of human error had played a part in the accident, although he was very cagey about it.
It gave us a problem in the hangers as one the six airframes slated as a “goer” suddenly became a “stayer”. An awful lot of ADD’s had to be rectified quickly!
Robert HiltonI would like that myself.
There should also be some film of the crash somewhere.
Robert HiltonSeeing as it has the small ventral tank, it is Airfix (an F1a). You could convert it to F1 by removing the external cable conduits (the two ridges fore to aft on the lower fuselage) and not fitting the IFR probe.
You could convert it to F2 by fitting an intake scoop on the spine.
For an F3 you would have to fit the intake scoop, larger fin and extend the cable conduits fore to just past the missile pylons.
I’m personally doing a 1:48 F1 (my first real attempt in nigh twenty years)
I’m not sure if I’ll use AFDS markings or try and scratch some 33 MU markings.
I’ll be giving it the tail no XM135. Probably one of the more famous F1’s.
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