garryAabout afterburner stage, this is from That_engineer_guy, i think most member here familiar with him
At an airshow the engine is used at MAX for dramatic effect. (Cool fire, loud noise, vibration, top-performance etc.) When you’re flying directly over a runway, one doesn’t have to worry about the Fuel Flow, or Quantity…:twisted:
Throttle settings are up to the pilot and his/her needs to fly the aircraft… Use as required for flight… :shrug:
If you need a little boost to bring up your speed, you may only use MIN-AUG. It will give you a bit more thrust with say only a 2x increase of fuel consumption. If you don’t need MAX-AUG for a particular situation, it’s best not to use it to save fuel.
➡ Side note: when the F100 is at MIN-AUG the nozzle only opens a slight bit from closed and shows no external flame. Other than the lack of some smoke, it is very hard to discern from MIL unless your hand is on the throttle, or can see the Nozzle Position or Fuel Flow Indicators. Standing on the ground or at the airport fence, most never know the difference
garryAYes, I know and?
I mean, still an impressive feat for a plane that went out more than 35 years ago.
It is a plane designed for a certain well specific role and still doing it flawlessy after all this time.The first one in nowhere near the one of the good old 31 but probably it was never intended to be like so, they just forget to even mention it in the brochures…
.
Not quite sure what exactly your point is, mig-31 is a very specialized aircraft, much like the SR-71, it sacrifice almost everything for speed, so it wouldn’t be so surprised that it surpassed others aircraft in that specific specifications
complaint that f-22 doesn’t have more supersonic range than mig-31 is like complaint that PAk-FA cant carry as much weapons as the B-52
garryA.
Or to say it in another way:
My plane is able to supercruise woo-ho, it can go for 151 miles at 1,2 mach without using afternburner, Whoo!
Not like your obsolete junk that need AB to travel over mach 1!
Yes, I concede you that after having done that it still travels 720 km at 2,35 mach but that’s is not supercruise, not supercruise at all, I won, I won!
part from mig-31 , no others fighters can do that , so it a moot point , and the mig-31 have to sacrifile various others characteristic such as agility and signature management
garryA2] he clearly states that its not supercruise in a technical sense, that leaves only a/b or dive, or deceleration
another possible case is that it rely on ab to breaksound barrier but after the transonic region , pilot can throtte back because wave drag is reduced
garryAA pilot would call it to “unload”, and F-35 had to unload in order to Reach mach 1.6 as well.
no one unload for 150 miles
turbojet engine AL-31F also lose thrust at those altitude.
It operate best from deck to medium altitude. So Lets not jump the gun here.
high bypass turbofan lose significantly more thrust than turbojet engine, just look at the Sprey engine F-4 vs the J79 F-4
and you think F-35 can maintain mach 1.2 at 50k feet on mil with 1.48 degrees shallow dive?
garryAok, so f-35 cant go m1.2 below 30k ft, that is troublesome indeed, is there any other fighter that ever had this limitation in history ?
anyway, the most likely is that he didnt count ‘a teeny weeny bit of a/b’ as ‘fuel-gulping a/b’
no fighter can go mach 1.2 below 20k feet with mil power alone, your assumption that it is a shallow dive from 45k feet to sea level mean f-35 can somehow cross the mach barrier (even go at mach 1.2 ) at sea level with mil power alone
garryAf-35 top alt is around 48k, and come to think of it he would fly on the hypotenuse,
so he can squeeze out a bit more dive angle to prove it did it, altho as he stated, not in a technical sense.
Of course, it may well be that since it was only a tiny little bit of a/b required in level flight,
there’s no real reason to mention the *too little to count* use of a/b, when its not supercruise in a technical sense anyway,
non-gulping use of a/b = teeny weeny bit of a/b, as opposed to full throttle ?
F-35 service ceiling is 50000 feet , but even if he started from maximum altitude and make a dive like you said , it still doesnt make sense at all , such shallow dive wont add enough force ( from 50K->30K feet is only 20000 feet , so the therotical dive angle is 1.5-2 degrees maximum) and a high bypass engine like F-135 will lose significant amount of thrust at high altitude too.
garryAsomeone with a pocket calculator handy, whats the dive angle ? 5 degree ? less ?
and while on topic: how the hell do i make degree symbol on keyboard ?
If you taken altitude from 40K ft to sea level , distance 150 miles , then the dive angle is 2.85 degrees
http://www.cleavebooks.co.uk/scol/calrtri.htm
However like Mig-31 said , such shallow dive angle wouldnt really add much force and while it may help at altitude around 40-30K feet , at lower altitude , it wont work , at sea level to 15000 ft even at maximum afterburner most aircrafts barely break the Mach barrier so it quite unrealistic to assume that F-35 can go mach 1.2 with mil power and 2.85 degrees shallow dive
On a more practical example , a shallow dive would only work at altitude around 40-20K ft ,since distance is 150 miles , if F-35 actually used a dive to maintain speed , the angle would be 1.43 degree
garryAI think one important factor that everyone over look is the load out of the F-35 in question, an F-35 fully loaded with 100% fuel and 2 JDAM will have a bit more drag than an F-35 with 50% fuel and 6 aam ( yes iam aware that they carried load internally) , that explains both testimony and also fit with the model created by the aerodynamic engineers
garryAAlso, two jamming planes within a single package can switch the currently active jamming source between themselves and make it harder for a missile to reach them if the switch happens during its approach.
True that, blinking jamming is a very effective way to deal with HoJ missiles
others effective countermeasures are towed decoy and terrain bounce jamming
garryA.
What is the tactical advantage that F-35 would achieve supercruising at 1.2 for roughtly 120km wasting an huge quantity of fuel instead of a normal higly subsonic one + a supersonic dash when needed?
).
Firstly, 150 miles is 247 km not 120 km
Secondly, ever single aircraft will waste a significant amount of fuel when fly supersonic, doesnt matter if it is Eurofighter or Rafale or F-22 or PAK-FA, 150 miles is not the maximum distance that F-35 can fly supersonic on mil power but rather the distance it can supercruise but still got reasonable range at optimum altitude, speed. ( similar case happened with F-22 when it’s mission profile only include 100 nm of supercruise)
garryARegarding the issue whether F-35 can supercruise or not , this is from the same aerodynamic engineer who estimate and produced the chart above :
As to Military Thrust Envelope issues my model would only be used for the Harrier, Stubby family, Tomcat, and Raptor. The rest I would take from the manuals. As to the Stubby cruise, my model currently supports (for example, this is not the only condition) 1.197M sustained at 36,000f and at a weight of 40,447lb (50% fuel 6 AIM-120D) with a specific range of .04782nm/lb. So With that fuel flow traveling 150nm would consume 3,137lb of fuel. It is not an issue of “It can’t go any farther in Mil power” so much as “that is how far you can go with still having a more optimum cruise segment and a reasonable range”. However, it is still very much a case of needing to use AB or a Rutowski profile to get there as the acceleration in Mil at M1.1 is only 0.02G (most flight manuals consider practical acceleration to end at 0.03G) or 0.66ft/s^2 or 0.39kt/s.
According to my model anyway. I have gone through great lengths and many iterations to ensure that my model supports all known verified performance claims.
garryA, it lets you run down or out run everyone else
an aircraft can supercruise doesn’t mean it have high maximum speed, you still cant out run an F-15 or Mig-25 in a Typhoon , had both of you accelerate to top speed
, engage or disengage at will,
This is not always true, it also depends on whether you can detect target or not
garryAdid you just miss out the published acceleration he stated by accident ?
which engine then, do you propose to make fatty spiffy from transonic on ?
you still don’t understand basic aerodynamic, engine thrust is not a constant value, each kind of engine is optimized for different speed range. A low bypass engine like F-119 despite having lower static thrust, actually perform better at high speed than F-135. The trade off is shorter range and higher IR signature. Everything is a trade off, designer choose what fit the requirements
garryA.
A focal plane array is like a low-resolution eye, only seeing different wavelengths.. no matter how high the resolution, it won’t see at longer distances unless connected to high mag optics.. just like a human with 6/6 visual acuity still won’t see a car at five miles without a spotting scope.. that is why your questions don’t make much sense..
A focal plane array detect/see object through the contrast in temperature with the environment ,hotter target have higher contrast , hotter target will also give off more radiation which will travel longer distance and result in longer detection range , there is no way around that.It not the matter of resolution we talking about here but the amount of infrared ( heat ) give off by the object.
You showed a video of F-22 in full afterburner being observed from few hundreds meters and said that all infrared reduction measuare have no effect , that is like saying , because your radar can detect stealth aircraft from 1 km aways so it mean stealth doesnt work.
Sign In
