SchorschThats an interesting chart. But as most of you know, thats a clean F-15. A sweet thing about the F-22 is that its clean even when its combat loaded. The combat performance advantage of the F-22 is even better than it looks here. I’m preaching to the choir, I know…
Right that is.
I want to say that I don’t like 100% of that briefings. Some details are in my opinion wrong or at least overly simplified, some comparisons lack conditions. Parameters like thrust-weight ratio, wing loading or fuel fraction are one possibility for comparison, but not the only one. I guess no-one here will say the F-22 isn’t a performer, but it always pays off to check out the numbers and do the math, even if some numbers need to be marked with footnotes.
SchorschWhile googling for “f-22 overweight” I found these two presentations by Pierre Spey and James Stevenson. Good read.
Both PDF, the later is quite big.
http://www.cdi.org/pdfs/Sprey%20Quarter%20Century.pdf
http://www.cdi.org/pdfs/Stevenson%20F-22%20Brief.pdf
This is from the second:
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SchorschHere is the data as I remember:
This webpage quotes directly the USAF page, but wasn’t updated for a while.
Primary Function: Air dominance, multi-role fighter
Builder: Lockheed-Martin, Boeing
Power Plant: Two Pratt & Whitney F119-PW-100 turbofan engines with afterburners and two-dimensional thrust vectoring nozzles.
Thrust: 35,000-pound class for each engine
Length: 62 feet, 1 inch (18.9 meters).
Height: 16 feet, 8 inches (5.1 meters).
Wingspan: 44 feet, 6 inches (13.6 meters).
Speed: Mach 2 class. and supercruise
Ceiling: Above 50,000 feet (approximately 15 kilometers).
Empty Weight: 40,000-pound class (approximately 18,000 kilograms).
Armament: One M61A2 20-millimeter cannon with 480 rounds; side weapon bays can carry two AIM-9 infrared (heat seeking) air-to-air missiles and main weapon bays can carry (air-to-air loadout) six AIM-120 radar-guided air-to-air missiles or (air-to-ground loadout) two 1,000-pound GBU-32 JDAMs and two AIM-120 radar-guided air-to-air missiles.
Crew: One
Inventory: Unavailable.
http://www.sirviper.com/index.php?page=usaf/fighters/f22
I guess if the “40k lbs class” is correct, it is the OEW (including pilot, unpumpable fuel, etc) and has some margin, so real empty weight would be 35000 to 38000 pounds.
SchorschIt’s an aviation discussion forum and that’s what we’re doing..or so i thought
While discussions about the performance of either company tend to become fact free pretty soon. The true causes for technical problems, if they are technical at all, are often not disclosed to the public. And often there is no single fault, it is a conglomerate of reasons, where one seemingly small delay causes another item to be shifted backwards, causing a delay elsewhere. It is the typical friction that is not accounted for, happens in any program. The big “failure” is hard to identify, and even if there is “failure”, it can hardly be reasoned that a company is “generally too stupid” to accomplish something.
What one can say that the schedules are from the onset unrealistic or very optimistic and against better knowledge. This is to pressure people and to increase the financial performance of the company, and the attractivity of the Executive Board to the shareholders. Finally it often turns out that it went exactly the other way.
The statements given by official Airbus or Boeing releases are like a Chinese newspaper.
SchorschThe F-22 is much more overweight than the F-35! For a stealth fighter weight saving material comes at second place in priority only, when to reach the lowest possible RCS. For the F-35B it is a real problem and not to hide.
None is eager to procure more F-22s in the moment.
The gap between the extreme hype around the capabilities of the F-22 and the very limited procurement is indeed surprising.
Concerning the weight, the data basis seems very inconsistent.
I found at af.mil (official USAF website)
http://www.af.mil/factsheets/factsheet.asp?id=199
an empty weight of ~20000lbs, which seems unrealistic.
Fun: when googling the page actually looks like this
Factsheets : F-22A Raptor : F-22A Raptor – [ Diese Seite übersetzen ]
Holloman Airmen hand stealth knowledge to F-22 community – 8/17/2007 … Empty Weight: 40000-pound class (approximately 18000 kilograms). …
I don’t know, seems like the USAF divided the empty weight by 2 recently. 😀
Wikipedia, most likely a fusion of different sources, gives ~14.5 tons empty.
http://en.wikipedia.org/wiki/F-22_Raptor#Specifications_.28F-22_Raptor.29
SchorschIts possible that the Soviets got their hands on F-4s when South Vietnam fell in the early 70’s. We turned over tons of hardware over to the armed forces of South Vietnam when we pulled out. The only F-14 rumors I ever heard of was the Iranians turned over a couple of Phoenix missles and let the Soviets get a look at the Tomcat’s radar.
There were no USAF bases run over by North Vietnamese soldiers. All sorties were flown from carriers or Thailand at the end. The Americans left lots of helis and light aircraft. The best the Soviets could get their hands on were the F-5E of the South Vietnamese air force, and they did it. A capable aircraft, but surely nothing that Soviets didn’t possess in terms of technology.
SchorschHi, I have no problem with the SH. But there are some setbacks by stealth-features introduced. One for example is more weight similar to the F-22.
None is intrested to open that discussion to undermine the still possible procurement of further F-22s and reveal the related details.
What exactly are “the related details” here?
Thanks for clarification.
SchorschIf you have a bigger or more powerful engines matched to a smaller inlet, the result would be faster acceleration and faster response at lower plane speeds, engine RPM and at lower altitudes. But you’re going to have a serious drop off beyond that—higher engine RPM, higher plane speeds and higher altitudes.
I guess you mixed that up:
powerful engine -> high mass flow -> large inlet for low speeds
A smaller inlet would suffice for higher speeds, especially supersonic.
SchorschFlight control issues were related to late firming up of software requirments thus making delivery late . The software IIRC has now been delivered to boeing .
Actually still a mistery for me how they could mess that up. Normally such things are “at hand” for new aircraft. I further do not understand why they source this essential piece of knowledge out. Boeing becomes an aircraft retailer.
Compensation is a big Mess as we know from airbus’s expereince . As of now boeing will need to look into the production schedule to see how many deliveries will slip . Different contracts are differently worded and compensation can be in many different ways , anything from discounted 777’s to discount over exerc. of options . Airbus used all of these effectivly to keep 380 customers comfortable with a 2 year delay .
I am sure that no airline will lose money through that, like none lost money due to A380 delays (maybe in some lost profits). I guess some lower profile customers will easier take delays in delivery as other. Some maybe even cancel or shift their delivery dates to 201x. As we learned with the A380, delay can extent as production people understand their problems fully when they standing knee-deep in the ****, and that normally happens when fully equipped (with cabin!) production aircraft are supposed to roll out, but don’t.
The development period for the 787 was very short and enthusiastic , …
Maybe that are two of the basic shortcomings of the B787 development period. :diablo:
SchorschThe ones with variable inlets for the SH not!
For the others it is the extra in accelleration or climb at first to restore energy state.
Even an inlet like that of the F-18A-F will generate extra thrust if engines are rated higher. The inlet takes away power, but at M1.6 that should not be overrated. Optimization of the inlet is another issue which cannot be assessed without detailed knowledge. Two seemingly similar inlets may have different characteristics.
SchorschIs there another kind? :confused:
Of course, and that is how most speed figures came into the books:
All modern engines have soft limits, basically software limits to preserve life-time and/or to reduce failure rate. Removing these limits will add some lbs thrust. Further on, for a maximum speed figure the aircraft is normally flown to altitude, topped up and then accelerated until it really doesn’t go any further.
That is the reason most maximum speed figures are not reproducable by average production aircraft, as these have limitations implemented.
SchorschNicht bis zur Bombadierung der Hydrierwerke.
Fuel was a problem ever since the invasion of Russia. The loss of the coal fuel plants made a severe problem to a catastrophic problem. This not only affected the readiness of the Luftwaffe, but also limited training and reduced number of available pilots. Until mid 1944 the Luftwaffe was generally able to field superior numbers of fighters, but lacked pilots and fuel to keep up sortie rate.
SchorschSince when we could evaluate the the performances of a fighter by observing cockpit photos??:p
You probably supposed that since both F 15 A/C and MiG 29 A have only one CRT, the MiG 29 can fight on a one to one basis with an F 15 :p
The diference between radar range, radar modes, radar jammer resistance, EW suites, AAMs means nothing to you…
And possibly the F-15’s CRTs are HD ready? 😀
Schorsch#1 – Luftwaffe fighter groups during the later years of the war were at about 50% mission capable, no matter what they tried. Not counting that the groups often had a shortage in planes in the first place. And those were compareably simple aircraft.
Fuel was the more dominant problem I guess.
SchorschIt depends on when you reckon design began. The start of formal, authorised design? The sketch of a concept?
Dassault was authorised to begin work on a technology demonstrator in 1983. That was what flew in 1986. Production decision 1988, first prototype of a real Rafale flew 1991.
The ACA conceptual design evolved from the late 1970s P.106 & TKF-90 concepts. Mock-up produced in 1982 – with twin tails. A technology demonstrator (one tailfin) began development 1983, flew 1986. It was a lot further from what was eventually built than the Rafale was. Prototype production began 1989.
Gripen requirement was issued 1980. Saabs proposal was put forward in 1982. Prototype flew 1988.
If you look at that lot, it’s hard to say design of any of them began before 1980, though all incorporated ideas from pre-1980 aircraft concepts, just as the F-22 (RFP issued 1983, contracts for prototypes issued 1986) does.
Design of the F-14 formally began in January 1966, but it included elements derived from the F-111. Does that mean it began design in 1958, when formal design of the F-111 began? If so, it’s more than 20 years older than Rafale.
It’s a continuous process. I actually don’t like to rate aircraft with their age, as an effective aircraft today is an effective aircraft tomorrow if no dramatic changes take place.
The more specialised an aircraft is, the more it will become outdated when the mission is gone. See for that F-14 or Tornado, also B-1B, the later two partly mothballed long before they were technically old.
Many designs of the 60s became obsolete because technology was at hand that made it possible to fullfil similar missions with smaller or more flexibe aircraft. These “game-changers” were control system design and engine technology, materials play a much smaller part I think. Avionics are also important, but are partly refittable (see F-4F or B-52H). A new “game-changer” may be stealth.
One should not forget that many aircraft are replaced for economic reasons. People in aerospace industry have to be busy. Otherwise that knowledge might vanish.
EDIT:
It is interesting to note that many “newer” aircraft took quite a long time from the drawing board to actual operation. The time-frame is round-about 10 years, some design like Eurofighter and maybe also F-22 suffered from stretched schedules after the Cold War ended.
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