FBWAgreed.
The F-35 zeliots seems to have a hard time understand how and when wave drag impact on a jet (any jet).
So seeing how the F-35 cruise at mach 0.8-0.9 which is in Transonic regime.
It will reduce range considerable.
So, you know the cruise speed of the F-35 in mil power at various altitudes? You know at what speeds the F-35 begins to experience a significant rise in wave drag? Or would you say that your posts consist of half-a**ed assumptions?
FBWno, that is not about it, it lets you run down or out run everyone else, engage or disengage at will,
intercept what none other can intercept, the speed means you dont need quite the quantity you would otherwise need
Really now, do you know speed difference between Mach .95 and Mach 1.2 at 30,000 feet? You really think that makes a huge impact on survivability? Please.
FBWI am not judging the drag of the F-35 by its looks rather than the published acceleration times up to M1.2 and its inability to supercruise..
Well, then your judging two different things. That wss my point. You can be very wrong about the F-35’s overall drag, yet the transonic acceleration points to an entirely different issue. Think F-102. Btw, been over it a million times. Acceleration through transonic for F-35 is certainly not bad, unless you are comparing other aircraft clean.
Again, go to my original post and rank them by drag coefficient and then by drag in the transonic region. It speaks to my point.
FBWLook at my response to Haavarla, you think you can eyeball drag too? Go for it.
Well, apparently Haavarla beat feet when asked to actually account for his statement. What about you Msphere any guesses without googling? Not going to drub you with it, the results are just interesting.
FBWHave you ever tried to put your hand out of your car wondow when doing 65 miles/100km/h?
Then angle your hand slightly and FEEL the direct impact on DRAG!When ever i see someone trying to downplay drag issue, i get slightly upset.. :/
Drag is a physical law that can’t be bypassed by a huge jet engine.. if F-35 has more drag from thicker wing foil and a fat airframe, then it will start getting higer IR signal.You want F-35 to fly supersonic, then say goodbye to low IR signatur all together..
You want F-35 to fly in transonic regime, fine, but while you are there you need to flipp your throttle handle to minimal AB from time to time.., so while the wingtip/rudders might not heat up any significally, you still need lots of thrust which generate heat.
Do you see my point?
Ok haavarla rank these five aircraft by drag coefficient:
F-18 hornet
F-15 eagle
F-16
F-4 phantom
F-104
then do the same rank for transonic wave drag
FBWDo we have some sort of comparison between the F135 and other engines? Or even an indication of the F135 being colder in that regard?
No, and most likely won’t. On one hand, the bpr of the F135 is on the higher side of fighter turbofans. Higher bypass ratio means cooler exhaust temp, ceteris paribus. But we know, for example, that the USN has had to modify the blast deflectors on CVN to mitigate the concentrated heat generated by the F135.
But, when considering this, the F135 is generating as much thrust as two F414’s. So, when considering the IR signature of the F135 exhaust, you have to take into account that it is generating as much thrust as a twin engine fighter, and most likely has a lower IR sig than two 20,000 lb thrust engines (at least in military power).
Of equal importance is that the cooling features of the LOAN nozzle do have a significant impact on IR signature. Exhaust gasses cool and dissipate. A hot nozzle is the single largest IR source for a fighter (excluding afterburner plume).
FBWOne need to temper, given the huge engine running at higher temperature than most, and a draggy frame generating more friction than most. So having a decent IR signature ,that is not bigger than most will probably be an achievement in itself. A lesser signature than current competitors would be mind blowing.
First of all, the F135’s combustion chamber operating temp and high thrust does not translate to hotter exhaust, despite the conventional wisdom on this forum. Second, draggier? Why because of looks? Certainly the F-35’s design (and missed acceleration goals) suggests a steep rise in wave drag in the transonic. That does not translate to “draggier” at subsonic speeds where it, and most every other fighter, will spend the majority of it’s operational life.
FBWCorrect.. the discerning reader can easily recognize that the advanced techniques for IR signature suppression are basically an afterthought, a cheap show in style “what is there on our aircraft that we can sell as IR suppression to the general public? Ah, here is that angle where you can’t see the nozzle, check feature #1..”
The thing is that even the most die-hard F-35 hater can’t deny that a great amount of thought has been devoted to the RCS reduction.. The overall result might be debatable and it is quite amusing to see you and others suddenly advocating the round nozzle of the 35 after a decade of dissing the same design when F-22 was on the cards…. but, again, the RCS reduction effort is definitely discernible… The IR suppression, however, is a different story.. There simply isn’t much to see.. the exhaust nozzle is jaw-droppingly huge and probably hottest in the industry, despite missing AB manifold the exhaust plumes are 20 meters long, just like ones on an F-4E, supercruise is non-existing therefore one can’t depend on military thrust only.. it doesn’t require a rocket scientist to recognize that at the time of designing of the F-35 no one cared about any of this..
OK, you do realize that the links I posted point to over 30 years of research into nozzle design. The F-22 nozzle came out of research from the early 80’s, the F-35 nozzle out of research from the 90’s. In essence, based on technology at the time, they could not make a symmetric nozzle with the requirements of the ATF. The LOAN nozzle was not even the original design for JAST or the JSF project. The original nozzle was a SERN nozzle like the YF-23, so your points are not only invalid, they show you did not read the background. IR reduction was not an add on, it was a requirement for the F-35 nozzle before the F-35 even existed. So no, again, there is a failure on your part to comprehend that what you want to see and what the research suggests are two very different things.
The F-35 does have significant IR reduction methods, and those investments were made years before the JSF project really became the F-35. As to the extent of the success? That is obviously classified. Why? Stealth shaping is widely known, as are materials, but exact composition, and more importantly manufacturing methods, are deeply classified. What have hackers from **** tried to steal? The shaping of the F-35 or B-2? No, concerted efforts have been made to steal information on the nozzle and IR reduction methods, that alone should tell you that your conclusions might need rethinking. There has been considerable (30+) years of research into IR reduction in US LO aircraft. My suggestion? Go to the Pak-Fa thread and take a long hard look at the current state of IR suppression in non-western designs.
Did you happen to see the Tu-160 footage from Colombia’s Kfir fighters? Imperfect combustion is a b8tch for IR and a trademark of Russian Turbofans.
FBWThat’s obvious.. except reduction of skin temp is of little practical use when you have a 1500+ Kelvin hot nozzle attached right behind it..
Don’t say… and how exactly have you reached that conclusion?
To be honest Msphere, I decided a long time ago that you basically come on this thread to troll. And that is fine by me, I get to read some studies and articles I’ve not read in some time and enjoy that. Not to mention, I do learn by refuting the stupidity some post on this thread,and it helps formulate ideas. Nice diversion from what I’m supposed to be reading and writing about. Secondly, you play the perfect uninformed dupe that you see on the comments section in news articles about defense projects (especially the F-35). Aping the idiotic notions of the Don Bacons and Pierre Spreys of the world. Our threads show up on google, so the discerning reader can look up the “world is flat” arguments and see the articles and studies posted here and make informed decisions.
The average citizen may be more likely to read the click bait of a David Axe story, but hopefully the more informed will be able to refute the stupidity of such articles with information from arguments such as these. As I know you are not a fool, because your commentary on all things flanker seem to be reasonably well informed, hopefully your coming on this thread and willfully ignoring the information presented to you serves some function of entertainment for you as well. I just hope that you are also taking the opportunity to learn from some of the information presented too.
FBWAll types with AESA radars field some form of internal cooling, usually using fuel as heat exchange medium.. Nothging new here, either, it’s only the F-35 gang who are screaming IR STEALTH !!!
BTW, if applying a coat of paint is suddenly a secret technique, then I’ll remind you that next time you claim MiG-35 (while fully covered with RAM) is not stealthy.
The double standard applied to F-35 vs. everything on this board is simply hilarious..
Wrong, most every other fighter uses liquid cooling (requirement for AESA), with ram air heat exchangers. The F-35 does have a unique system in that all electronics/environmental cooling is integrated. The ICP, AESA, EW, are all liquid cooled. The ECS of previous fighter aircraft use inducted air as the medium for heat exchange The IPP uses fuel, engine bypass air, and the scoop on the top of the wing glove. Using fuel as a heat sink is not unique, commercial aircraft have used that technique some time, the degree it is employed by the F-22, F-35 in a fighter sized aircraft is relatively unique and driven by RCS requirements as well as environmental cooling needs.
The RCS reduction paint like IRON BALL, has been used for decades. It does reduce RCS, but even an order of magnitude reduction for the Mig-35 is not terribly significant. The F-16 has been treated with such paints and Canopy HAVE GLASS treatments, does not make it a LO aircraft does it?
The IR topcoat has been stated to reduce long wavelength IR signature significantly. You can take it or leave it. It just disproves your notion that the F-35 had no IR reduction measures.
QuantumFX- read previous page, not going to repost all. But I can confirm that whoever posted this http://forum.keypublishing.com/showthread.php?66605-PAK-FA-updated-info-anyone&p=1104016#post1104016 was full of it. The research for “non-axis symmetric 2-d nozzle” is available. The 2-d wedge nozzle was chosen for a variety of reasons, one of which was that it offered reduced IR signature and ease of cooling. Just to add though, the primary driver was reduced drag and excellent dry thrust performance.
some of the research-
The 2-D/C-D nozzle shows 35% reduction in dead aft infrared radiation (IR)
level relative to the baseline BBN when installed on an F100 engine
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19780010127.pdf
Research that went into choosing the F-22 nozzle:
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19780020114.pdf
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19820018365.pdf
FBWAs said, those are no IR suppression techniques.. Just plain things masqueraded as something “advanced”.
..
Really? Do tell what leading edge cooling is employed on the Su-35, Pak-Fa? What type of IR suppression paint is applied? What method do they use to cool the con-di flaps, and where is the airpath for cooling flow into the nozzle?
FBWMeh, Msphere will shrug off the points. But for those interested, here are some of the IR sig/thermal management features (interestingly, some former studies, patents, and articles that I remember reading are no longer. The recent {and ongoing} espionage by a certain nation, especially on IR reduction, has led to a curtailment of open source documents)
F-35 IR sig
First off, GE LOAN patent- not chosen, similar in concept:
https://www.google.com/patents/US6983602
P&W LOAN nozzle:
http://www.f-16.net/f-16_versions_article20.html
FlightGlobal- LOAN nozzle tested:
https://www.flightglobal.com/news/articles/pampw-low-observable-nozzle-tested-on-f-16-10193/
The 3BSD was then combined with low-observable, or LO, axisymmetric nozzle designs that had been recently flown on the US Air Force F-16 fighter. Pratt engineers also dug into their archives and found much of the original design and test data on the 1960s development of the 3BSD. They also found designs for moving duct liner cooling air across the bearings
http://www.codeonemagazine.com/t50_article.html?item_id=137
The classified “sawtooth” features that ring the nozzle help consolidate the exhaust into a so-called “spike” signature, while other secret techniques have been employed to combat and minimize the engine heat signature.
“We had to deal with that, and we dealt with that,” O’ Bryan said, declining to offer details.
The F-35 meets or exceeds the services’ infrared signature specifications.
-Airforce Magazine
short description of thermal management system, with some issues that had to be resolved
Liquid cooling system for F-35, not really unique but LO aircraft cannot have external heat exchangers.
https://www.1-act.com/markets/avionics/
The Spirit, Raptor and Joint Strike Fighter apparently all feature gear for cooling hot leading edges such as the fronts of wings. They also boast systems that sink much of the heat generated by the on-board electronics and actuators into the fuel. The F-35 in particular pushed that concept to the extreme. “We’re out of heat-sink capacity for the F-35,” said James Engle, a former Air Force deputy assistant secretary
.-https://www.wired.com/2012/12/steath-secrets/
IR reduction paint- Boeing developed the first version in 2000 TOPCOAT:
http://boeing.mediaroom.com/2000-03-23-Boeing-Develops-Stealthy-Topcoat-for-F-22-Raptor
Some already posted by Hopsalot
FBWThese practices are nothing short of a freaking blackmail..
There are two sides. Yes, despite the L-M comment that they may pull future contracts is not a threat, it is, of course, a threat. Then again, Canada is not losing existing contracts, they will not be allowed to bid on new ones. Is it fair? Well, if you have an agreement to buy a product in exchange for workshare, and you renege, how are you entitled to continue? Exactly how rare do you think this is? Does BAE systems U.S. get workshare on the Typhoon because the parent company is part of the Eurofighter consortium? No, it goes primarily to partner nations. Blackmail would be threatening to pull existing contracts, which they cannot without legal action anyway. Lockheed does not “owe” Canadian aerospace companies workshare, the economy already received contracts far in excess of Canada’s investment in the project.
It will be interesting to see how the Liberal gov will “spin” a Boeing purchase. There will be precious little industrial cooperation for a production line that is winding down. The long lead item pipeline is diminishing as there are no firm orders to carry the F-18 E/F beyond 2018 (unless the Kuwait order firms up, there are two Supers in the FY 2017 budget with 12 in”unfunded priorities”), the 14 in 2018 are not definite. Canada’s order is not going to be large enough to grow the supply chain. Basically, not choosing the F-35 will kill Canadian aerospace companies, or more exactly, choosing the F-18 E/F by sole source contract will. At least with an open competition perhaps Saab, or BAE could offer industrial partnership.
FBWThere are no IR suppression measures to speak of..
No, none at all…and the world is flat too.
Bail on that now, evidence to the contrary is overwhelming.
FBWLook at 2016 ACC doc I posted above. What does it say about runway weight bearing requirements for the F-22, what does it say about fuel requirements?
Seriously, 2+ pages of people trying to parse what is clearly stated in documents because it doesn’t fit what they want to believe. It’s funny, if I posted a document that stated “Water is wet”, it’s like there would be people arguing “well, it can be damp, what about water vapor?”. I don’t know about other air forces, but in the US, if you deviate from the standard procedure, you better have good reason and be able to support it. Bottom line, the F-22 starts a display with 18,000lbs of fuel unless runway restrictions, altitude/airspace, safety concerns, curtails or leads to deviation of the display.
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