SchorschWhat’s the spooling down time of a RR Pegasus – and how does it effect the crew escape time of the Harrier while in the hover stage of flight?
I’m presuming of course, that the spooling down time of a tubofan increases in parallel with the increase in the By-pass ratio…?
I’m not sure about the last comment. Turbofans have probably more inertia, but at the same time the fan does actual physical work, so is slowed down.
When looking at large bypass turbofans at airports, you recognize that engines slow down considerable within a time frame of one minute.
Anyways, the N1/N2 speed over time after fuel cut off would look like a 1/x function: huge speed loss in the beginning, and a longer time with some residual shaft rotation.
1/x: http://www.matheplanet.com/matheplanet/nuke/html/uploads/6/7723_1_3.jpg
SchorschWhat the Russians could easily do is shoot a group of nuclear armed missiles in first, have them air burst detonate at a safe yet effective EMP range perhaps – crippling the CVBG’s ability to detect anything, then pummel away with the rest of the payload.
A carrier is also a very good bait.
See World War II, various sea battles, from Midway to the Leyte Gulf, were either Americans (Midway) or Japanese (Leyte) used carriers as baits. The relative strength of the USN in 1944 prevented the bait to be effective, but Halsey gambled his entire 7th fleet to hunt some strategically meaningless carriers.
SchorschBesides, even a surface explosion on the flight deck would be a “mission kill” for the carrier, which would be crippled and head home.
SchorschIf you recall back in the ’80’s, a German teenager managed to evade the might of the Soviet air defence system and land on Red Square in Moscow.
In a Cessena.
Rust could fly so slow that most modern radars won’t detect him.
SchorschSorry did not make the sarcasm clear enough.
However I find it very interesting to provlaim that the F-4 was not needed for the defence of Great Britain, when you have the Tornado F-3 as the replacement, which seems just a little closer to the F-4 the to the Lightning imho.
Oh, missed that one. My pathetic German humor.
I think the Lightning cannot be considered a viable platform for air defense, pretty much from its IOC to its retirement. Its weapons are not all-weather, it has too limited endurance and no effective on board sensors. Nice performance islands granted. But in its initial job (defending Queen’s islands from Bolshevist bombers) the Phantom outpaced the Lightning with a huge margin.
SchorschTwo things would have put interesting twists on RAF history.
1. Avon powered F-4’s.
2. Adoption of the Saab Draken as a light interceptor.Typing on an iPod, will elaborate later.
Edit:
1. The Avon 301 family offered relatively similar performance overall to the original J79 because for the meager loss of thrust you also lose nearly an identical amount of weight. The mass flow rate is similar for the most powerful Avon and the J79, therefore less problems with the intakes. You did trade/lose some dry performance compared to the J79, but your wet performance had a nice drop in sfc compared to the J79. If you take a look at the overall difference you still had the same issue with the engine diameter as the Spey, but fewer nags at the end of the conversion.
2. The RM6 produced for the Draken (aka Dragon) by Svenska Flygmotor was a warmed over Avon. The British would have been smart to field a high-low mix of Lightnings and “Dragons”. The Draken offered the same limited ground attack capability they were getting out of the F-4, therefore making the latter unnecessary. And the Draken offered the capability of using radar-guided missiles, which is something the Lightning did not offer in its entire career. (Which missile is a whole ‘nother matter.) No doubt the Sea Vixen needed replacing, but perhaps they could have figured out something other than Spey Phantoms for the job. (OT – a navalized Viggen would have absolutely rocked!) The Draken enjoyed success as an export, so imo there is no reason to doubt the likelihood of this being an option.
Pretty insane mix.
Why replace the original engine in the Phantom with one that offers no advantage? When you put turbo-jet versus turbo-jet, the SFC in full reheat at M=0 is of no significance. Or do you have full installed SFC data for both engines over the whole Mach and altitude spectrum, including partial power performance?
The point about the Spey was to increase capability. And it did.
The problem with the Lightning was that except for firing two heat-seeking missiles at an opponent identified by ground radar, it wasn’t good for anything. As a fighter it might rule the one-vs-one arena (as impressively shown in this thread), but as the mainstay of a fighter force it is no option (lack of endurance, both fuel and weapons, no on-board sensors …).
Schorsch2) AIM-7 and a radar the even offered early look-down capabilities was surely not needed.
Without look-down capabilities an opponent is able to force the fighter into undesirable positions, possibly even denying a shot at all. You can go without it, but I think it increases the ability significantly. For a continental European theatre with low level intruders radar guided missiles without that capability are nearly useless.
Schorsch1) The U.K. did not need that capability. It was a luxury.
Before the early 1970ies there was no alternative for frontal attacks than radar guided missiles. And especially in bad weather (and look, that is supposed to happen in and around the British Isles from time to time) radar guided weapons can do the trick. An intruder aware above the Liughnings shortcomings would just fly in the clouds.
2) The F-4M was not helpful for intercepting high flying intruders.
Crap. It wasn’t a big performer in dry thrust, that is accepted. But who cares for dry ceiling? Nobody was afraid of MiG-25 attacking UK.
3) The British had other attack jets that could satisfy their needs.
The Phantom offered more versatility than all other types.
The Spey Phantom was a dog above 35,000 feet and almost useless above 45,000 when the engines “ran out of steam” as Squadron Leader Riley put it.
Things were supposed to happen below 10000ft in Europe most of the time.
SchorschI personally do not believe we will see anything bigger than the A380 for many, many years, perhaps ever. Furthermore, I believe the A380 will have problems being a commercial success. The trend for the last 25 years has been towards smaller airplanes……2-300 seats is where the action is, IMHO. 767-787, A330-A350 sized airplanes are the future.
Those arguments can be opposed by other that have the same reasoning: Boeing sold more than 600 B747-400 in 20 years. Now the passenger volume has more than doubled, and Airbus would be totally happy to sell the same 600 A380. Note that when the B747-400 came out, it wasn’t purchased due to range any more. It was capacity.
Boeing does Airbus the favor of slowly scrapping the -8I project, cancellation can be expected within this year depending on overall market situation. Very unlikely they will ever restart it, so Airbus is the only one there.
Before an aircraft bigger than the B777-300ER get available, at least 10 years will pass. After the B787 Boeing must put its attention on the Single Aisle market, like Airbus.
And airlines get bigger. In a few years we’ll have three big airlines in Europe, probably only three network carriers in North America and no one knows how it develops in Asia.
In the end, many arguments can be said for or against the A380.
SchorschGuys, highly enjoyable to read all these accounts here.
Still supercruise not mentioned. :diablo:
Keep it on!
SchorschMy bottom line when opening this thread was that couldn’t imagine the first generation supersonic aircraft a.k.a. Lightning win a battle versus the Phantom. I am still not truly convinced (bias is strong), but I see that under certain conditions the Lightning holds many trump cards.
At 30000ft, versus a non-slatted F-4, which is limited to rear aspect Sidewinders and maybe even lacks a cannon, the F-4 is probably better advised to run for home. A slatted F-4F maybe stands better. Crew performance was mentioned a key factor.
From that one cannot make the conclusion that the Lightning would make a more powerful air force. I guess that is the wrong conclusion. The Phantom offered as package probably offered a significant increase in capability, especially when looked at by capability per pound sterling.
In the end, this thread was on of the better ones, and nobody mentioned supercruising Flankers so far. Thank God!
SchorschWhat people tend to ignore is numbers.
Let’s assume for a second the F-35 is inferior to all contenders in WVR.
But now assume the USAF can field twice the number.
History shows quite impressively, that it is not superior aircraft in small numbers, but reasonably good (*) aircraft (and the F-35 surely qualifies for that) in larger numbers dominate the battle.
(*): “reasonably good” in terms of flight performance
SchorschWell Boeing did some research into this when devoloping the 747-8. They concluded that the way the industry was going, airlines would be more interested in efficiently delivering a higher frequency of service, than moving as many passengers as they could in 1 or 2 flights per day. Hence the 747-8’s capacity was not increased by much from the 747-400.
Which is also largely due to the fact that the basic B747 design couldn’t be enlarged much more before a truly new design is necessary. And doing that the product wouldn’t have been very competitive. So Boeing made the reason the conclusion.
Well, Boeing acted of course smart, as a second A380-like product would mean disaster for industry (like DC-10 and L1011 made both airframers suffer, when would have been a worthwhile investment).
The A380 and its growth variants are the maximum which can possibly achieved within the current limitations given by the basic design principles and the infrastructure.
I doubt there will be a demand for anything larger in the mid term future (until 2030). It is still unclear if the A380 is a success. Many say yes, some say no (that is: not people on forums, but people that know the industry).
SchorschWhich brings up an interesting point. Given that at mil power the F119 can push the F-22 well in excess of supersonic and the fact that you typically DON’T want to be doing that over populated areas (where the F-22 bases are incidentally) what are they doing to keep speed down to a reasonable level? :confused: And the next generation of engines currently being researched promise to be even worse in that regard (lots of power at mil.). Will that demand a switch (finally) to a variable cycle engine like the F120?
I guess in normal peacetime operation the F-22 will have a limiter. This limiter might be removed or eased when more realistic training is due. But I doubt that the F-22 is always in full combat performance mode. Doing that wouldn’t be smart, and would waste lots of resource for no real advantage.
Optimal would be an engine that works as a medium bypass engine (medium for military applications, so BPR of 1 or so) and as a pure turbojet or very low bypass engine for supersonic speeds.
I actually doubt that there will be so many investments in future manned combat aircraft at all. Research yes, but a new generation of engines optimized for F-22 like performance, I doubt so.
SchorschSchorsch,
The F-15 had many advantages over the F-4. Acceleration, a much better radar, and better pitch rates, for starters. Closer to carefree handling at low speeds, and much better visibility from the cockpit.
It’s not all about g.
(And when the F-15 was limited to 7.33 g, the F-4s (with their ageing airframes starting to exhibit all sorts of structural problems) had lower peacetime limits themselves.
No dispute. I just wanted to say that – at low level – it wasn’t day and night. More like day and dawn.
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