F-35B ready for ‘high alpha’ tests

It’s hard to imagine a much scarier scenario than turning off the engine to an aircraft in flight to test if it’ll restart.

That’s just what Navy test pilots did with the F-35B Joint Strike Fighter this summer. And lucky for those pilots and the Joint Strike Fighter program, the F-35B and its F135 engines turned back on.

Navy officials announced the F-35B passed  it’s “air start” tests meaning the program can move on to “high alpha, or angle-of-attack tests” — the maneuvers that set the fifth generation fighters apart from their 4th generation (F-15 and F-16) peers when it comes to a dog fight

“High alpha, or angle-of-attack tests, are important for us to fully evaluate the aircraft’s handling characteristics and warfighting capability,” Marine Corps test pilot Lt. Col. Matthew Kelly said in a statement. “Maximizing the performance of the airplane around the very slow edges of the flight envelope is probably some of the most challenging testing we will conduct. After we get through it, we’ll know a lot more about how this aircraft will perform during combat within visual range.”

Test pilots completed 27 engine restarts at different altitudes of flight, Navy officials announced Tuesday. The Navy completed the tests at Edwards Air Force Base, Calif., over the Rogers and Rosamond Dry Lakes.

Air Force officials have already completed air start testing on the F-35A. Navy leaders said they were able to benefit from the Air Force’s experience.

“We’ve recently completed air start testing on the F-35A, so we’re able to share some of our expertise with the Pax team as well,” said Lt. Col. George N. Schwartz, Commander of the 461st Flight Test Squadron and Government Site Director, in a statement.

About the Author

Michael Hoffman
Michael Hoffman is the executive editor at Tandem NSI and a contributor to Military.com. He can be reached at mhoffman@tandemnsi.com.
  • Benjamin

    Finally some good news about the F-35

  • Not too scary when you have two engines.

    • ChuckYeager


    • Menzie

      What? You think they leave one running? The whole is simulate failiure geez.

    • tiger

      The 2nd engine on the “B” is for landing, not forward flight.

      • cs4

        That “second engine” is tied to the first engine for power.

    • Vyger

      Wow! – maybe you guys need to do a little simple research to find out the F-35 is a single engined aircraft with the one engine also driving a lift fan! – face palm!!!!!

      • Nate

        I assume that was the joke.

    • Wayne

      The F-35A-B-C are all single engine aircraft.

  • Pilgrimman

    Glad to hear it. Can’t wait for this baby to enter service!

  • ghostwhowalks

    I say all credit to the test pilots who take on the risks

    • Johnny Ranger

      No kidding. I don’t like to turn my CAR engine off!!!

  • Skyepapa

    This is one of those tests that hits a milestone no matter what. If the test succeeds, we’ve hit the air-start milestone; if it fails, we’ve live-tested the ejection seat. Win/win!

    • Curt

      While I am not a test pilot, I would assume the reason they do the tests at Edwards is that in the event of a failed restart, they can make a deadstick landing on the lake bed. Not a win-win, but a win-win-win since they probably have a checkpoint for deadstick landings as well.

  • tee

    With all the buffeting that has been reported with the the F-35 on shallow dives the next set of test make or brake the program.

    • Ed

      Well, didn’t they use to tout that it was all about BVR and stealth? Probably it’ll go on regardless of the results (for as far as reality will deviate from predictions – I doubt it’ll be that much)

  • 4FingersOfBourbon

    Que Black Owl….

  • 4FingersOfBourbon

    Que Black Owl….”The F-18 Did that test back in 79’….come on! POS!”

    • Skyepapa

      barefoot and in the snow, no less

    • Riceball

      In the Super Duper Hornet the engine will restart itself.

  • Naska1

    Canada is getting a squadren of 60 f-35 jets !

    • Menzie

      No squadron is made of 60 jets….geez. That many makes multiple squadrons.

  • Josh

    Good news finally. Major props to the balls of steel test pilots aswell. Hopefully this thing keeps up with the good news.

  • BlackOwl18E

    @ 4FingersOfBourbon and Skyepapa, in the words of Bane from the Dark Knight Rises, “speak of the devil and he shall appear.”

    I am not impressed. The F/A-18 series has two engines and not only was it able to conduct this test earlier in its program; it was able to do the same test twice in the same flight. Two engines are always better and when the F/A-18 did this test it was much less risky because of the second engine. These test pilots had balls, but the only reason everyone thinks doing this in the F-35 was so scary is because of the fact that it has only one engine, which doesn’t have all the kinks worked out yet. The danger to the pilot’s life was greater for this test than it was for the F/A-18. Think about what that means for Navy pilots who have to fly over the water all the time. From my point of view this test just made the Super Hornet look and feel much safer to fly than the F-35.

    I would also like to point out that the Navy has not done this test yet with the F-35C. The C-model is the one that I am most critical of and the fact that it hasn’t even done this test shows how slow its progress is as well as the Navy’s reluctance to continue with it. Pretty certain the Navy’s using more effort to try to get out of the program than they are to actually move it forward, partially because moving it forward seems too expensive and not worth the return even if they actually did get it going.

    Apart from that, this test is nothing. The F-35 still hasn’t performed spins testing and of the vast arsenal of fighter jet weapons that we use and can use in the theater of war it has only released a few bombs. It hasn’t fired any missiles or any of the special munitions like JASSM. The gun pod for the F-35B hasn’t been fired yet. The dropping of two bombs means almost nothing in terms of the fighter’s usability in a combat environment. It still hasn’t trapped a wire, the helmet still doesn’t work, and the F-35B still has structural integrity issues involved with vertical flight. These are the problems that get my special attention. This jet still hasn’t done anything worthy of note and it is still nowhere near its worth in cost. The only way to save the program is to cancel the F-35B and F-35C, then let the USAF focus on developing the cheapest and simplest version, the F-35A. Silent Hornets armed with better anti-radar missiles would satisfy the needs of the USN more cost effectively and an upgraded Harrier III would do the same for the USMC.

    • DeuxSchnozz

      While I thumbs-upped you for the most of this, I’m very curious as to what this “Silent Hornet” and “upgraded Harrier III” are.

    • SirSapo

      So the fact that it successfully passed its air-start testing makes you feel worse about it for some reason? The whole reason they do these tests is to ensure that they can get a restart during the high-alpha testing if the aircraft departs and the engine stalls. You do know that during multi-engine aircraft departure testing they practice dual engine shutdown’s and air-starts, putting the jet under the same amount of “danger” as a single engine airplane right?

      • BlackOwl18E

        I now know that you are not an Aeronautical Engineer like you claim to be. Two shut off engines means that there is an increased probability that at the very least one of them will turn on. That’s the whole point of having two engines. The risk was not the same. Even the simplest mathematician could figure that out. I have no idea who you are, but you are not who you claim to be and I have lost respect for you.

        • Johnny Ranger

          Didn’t work out that way for Maverick and Goose…

          • blight_

            The Tomcat’s engines were notorious.

            From raw probability alone, assuming aircraft A has two of engine X and aircraft B has one of engine X, the probability of total engine failure in aircraft A is lower than the probability of problems in aircraft B arising from the engines. Then again, it introduces the probability of a one-engine fail, one-engine intact situation, which has to be designed and planned for as well.

            I imagine the jury is still out on F-35 engine failures, and we’ll probably find out more once we put on the flight hours and use mass production engines instead of special-build or low-volume orders.

          • BlackOwl18E

            The F414s are much different. They build on the reliable engines already in the Legacy Hornets. These are engines that hadn’t had a dual unrelated engine failure until the recent incident in Virginia. Simply building on the technology was one of the most low risk options to provide increased capability. The F-35’s engine is the most powerful jet engine on earth in terms of dry thrust/weight ratio, but it is also complex and uses new technology that hasn’t yet proven to be reliable. All I’m saying is that the risk was greater and that two engines does make a difference in the amount of risk taken. If the F-35 had two engines of the same type that it’s using now there is an increased chance the pilot would achieve engine start up.

          • Atomic Walrus

            The failure rate on modern engine technology is incredibly low as it is – no need to toss in “dual unrelated” as well. About the only thing twin engines will do for you is add some robustness to damage in combat. Even that’s not assured, though. You should also consider that dual engines means dual inlets, with only one inlet per engine. The single engine F-35 has got twin inlets, making the propulsion system more robust to inlet unstarts. That would tend to reduce the need to engine restarts in flight compared with a twin engined aircraft.

          • Chuck

            While two engines provide a degree of additional reliability, they also add weight and size. You essentially double all the equipment while adding less trust to weight ratio. This also adds to maintainence costs, requiring twice as much time to keep them running. The F-35 engine is an improved version of the F-22 engine, so it is not completely new. Actually more like the early F/A-18C/D engine to that used by the F/A-18E/F. The engine has already been tested to death by the contractor, and it has worked well enough for DoD to call for only one engine supplier. While I appreciate your love for the F/A-18, the F-16, with significant combat action, has proven that a single engined aircraft is not significantly more dangerous than twin engine jets.

        • SirSapo

          Personal insults aside, I think you are confused as to why we do airstart testing, and specifically, why they are doing them on the F-35 before high-alpha and departure tests.

          The reason for the test is they want to have confidence that they can get an engine relit if they suffer a flameout during a more violent than expected departure. Modern engines are very very stall resistant, but if you start feeding them really messed up air (due to some violent post-stall gyrations or something of the sort), they might stall or flameout. If that is the case, you need to either restart it in flight, or glide to a suitable landing location (ie. the Edwards Lake Bed).

          The point I was making was that you are somehow less confident in the F-35 after this successful test of an inflight shutdown and restart, when it is a normal procedure for any fighter aircraft to go through.

    • Ron

      It’s spawned of Lockheed Martin not Northrop.Wake up Northrop!!!!Get busy-we need your help!

      • Ethan

        Northrop makes a large portion of the fuselage, IIRC

    • platypusfriend

      After all the “cue Black Owl” posts, above, I was sloowly mousewheel-scrolling down, waiting..just waiting!..to see a blue “BlackOwl18E” peek into the bottom of my screen.

      I had to give the man a thumbs-up.

    • brad

      I agree. Given future projected costs of the all three variant’s, it would have been much smarter for the USAF to keep producing the F-22, expanding the capacities of the F-18 (future updates to growler,etc.) and trying to build a market for the F-15 SE (Silent Eagle Variant) both domestically and abroad. The rising costs of the F-35 is insane…. Hope its worth it in the end I really do, because I honestly see our foreign buyers, at least beyond the tier 1 partner level, reducing their orders drastically, or pulling out of the program all together. After all; one can buy a hell of a lot of 4th gen planes for only a handful of these sensor packed bad boys… and someone wanting the perception of force projection is going with numbers, not quality.

      • brad

        I meant of course the USN in regards to the F-18… but I’m sure on this site, that goes without saying ;)

      • ST Dog

        Insane you say. Compare to historical programs since WWII. Use percentage on delays and cost overruns.

        I think a lot of people forget just haw costly and off schedule past programs were. They also forget the growing pains of the now established programs.

        Look back at the history of acquisition reforms in the DoD and why the were implemented. Even though less than successful, the causes were the same stuff we are griping about now.

        And I think a lot of that “bad memory” of the past is because the industry wasn’t as open as it is now. 40yrs ago we couldn’t easily find out what was going on.
        There is a much higher level of scrutiny now, especially by the public.

        • brad

          Ya… if people knew the cost of black projects throughout the 1940’s-well into the 1970’s they probably would have been in disbelief. But no one complained because we had a reason to build these weapons… we had our eastern demon… now we have a new eastern demon… PLA

  • jamesb

    When does this a/c go to the fleet?

    When does it go to the oversea’s customers?

    • Chuck

      Two international F-35s have already been delivered. One to the UK and another to the Dutch. While the F-35C version is still developing slowly, there are 19 birds at least dedicated to training at Eglin AFB. The F-35 variants still have considerable weapons and handling testing and a lot of software work, but testing has been moving rapidly as of late. The aircraft will be in a much better position in another year, barring major structural problems found in the upcoming high AoA testing.

  • matheusdiasuk

    Royal Navy liked it

    • BlackOwl18E

      They can’t afford it. They’re experiencing harsher defense cuts than we are.

      • Why can’t the UK just admit it and disband their Navy.
        They prefer “investment” into social programs more than having a Navy.
        They should just get it over with and get rid of the Navy and roll what money is left over into the Air Force and Army.
        Or take the money and order out some fast food for Parliament. If there is that much…..

        • Tiger

          Now, now. If they can pull off the London Games, I’m sure they have a few Euros for a Royal Navy.

          • eaglemmoomin

            Oh dear pounds not euros now you just look ignorant!

        • matheusdiasuk

          If there is something to be disbanded in UK, is political incompetence.

  • PolicyWonk

    While I agree that especially in the naval context, two engines are better than one, the US (and many other countries) has (have) been operating the F-16, also a single engine fighter for decades.

    How many of these over the years have suffered failures and been lost due to having only one engine?

    • Curt

      The simple fact of the matter is that jet engines have become so reliable that the number of engines has very little to do with how many aircraft are lost. Usually it is pilot error, which all the engines in the world can’t save you from.

    • tiger

      We have come a long way since the weak jets of the 1950’s. No engineer would need 8 engines on a B-52 today. Even tri jets like the 727 & L1011 have faded from Airline service for twin designs.

      • Charley A.

        And yet, you don’t see commercial airliners with one engine, and even twin engined jetliners have restrictions/rules about how far they can be from suitable airfields when operating on transoceanic routes.

        • Tiger

          That is due more to size and plane configuration. A single jet typically is inside the fuselage. Way too noisy for passengers.

          • Riceball

            My thoughts exactly, the reason why there’s no single engine passenger jet is because the engine would have to be stuck inside the fuselage which would take up passenger and/or cargo space. Either that or you stick it up on top like the Germans did w/the V1s and the Voksjaeger fighters but I imagine that would probably result in a lot of noise and vibration being transmitted to inside the fuselage and I’m not entirely certain how well mounting it like that would work on a large jetliner.

          • STDog

            Lots of 3 engine airliners, like the 727, DC-10, and MD-11.

            The reason for no single engine airliners is FAA regulations.
            And you won’t see one either.

            In the 50’s, the FAA limited 2 and 3 engines to stay within 60 minutes of an airfield in case one engine was lost. (quads were not limited like that). In the mid 60s that rule was waived for 3 engine craft.

            In the mid 80s, the FAA allowed twins to go to 90, then 120 minutes from an airfield, and in the late 80s now that was extended to 180 minutes. All have strict design and qualification requirements to get ETOPS ratings.

            In ’07 the FAA opened up a longer rating, to design limit. Last Dec the 777 was rated for 330 minutes.

            The rating means the aircraft can fly at full load for the listed time on just one engine.

    • Charley A.

      More than you think. There have also be a number of engine-out recoveries of F-16s that glided deadstick into airfields – which is something that you cannot do with a naval aircraft out of gliding range of land. Plus recovery is next to impossible on a carrier with zero or severely degraded thrust. Hence the concern of naval aviators that have proven the Hornet/Super Hornet is the safest jet that the Navy has ever operated.

  • Ed Cahill

    On the B is the pilot going to be able to adjust the trust angle —”viffing” like the Harrier? If so I would think that this plane might have a few nasty tricks up it’s sleeve in dogfight.

    • Ed

      Would that work without using the fan? It would be just like a limited kind of TVC otherwise, right? I don’t think they designed the lift fan door for operation in dogfighting.

    • Chuck

      Don’t think I want all those doors opening and nozzles turning during a dogfight. The nozzles on the wingtips mights be useful with a lot of training, but not really the same as the Harrier experience.

  • Johnny Ranger

    You, sir, are a reckless thrillseeker.

  • Rod

    Can an Aeronautical Engineer please explain to my why an engine restart is necessary for stalls at high angles of attack? I thought stalls at high alphas were caused by the orientation of the wings not being suitable for lift because of Bernoulli’s Principle (i.e. the air flow across the top surface of the wing no longer experiences higher velocities and therefore no lower pressures that cause lift). I mean isn’t that why they use thrust vectoring- to increase airspeed at high alphas?

    Blackowl, it seems to me, from my limited understanding, that the C variant isn’t being rushed into high alpha testing because it has a bigger wing surface than the others. The fact that the B variant has a more complex engine setup used for VTOL maybe the reasons engineers wanted to test an air start.

    Also having two engines might not exactly be “safe” considering if only one comes on, it will cause the aircraft to yaw and spin.

    • Sufa Viper

      I wouldn’t call myself an Aeronautical Engineer, but I do have some understanding and insight concerning your questions. When you get to a high alpha the flow starts seperating from the top of the wing and the engine inlet. The result is a turbulent flow or if the angle is steep enough it can theoretically reduce the flow into the engine to near zero. This starves the engine and can choke/stall the engine. Once you have a stalled engine you need to nose over to get the airflow going again and allow your engine to breath and hopefully restart.

    • tiger

      Stalls happen for different reasons. Lack of lift and lack of thrust are both causes.

    • Charley A.

      SV is essentially correct – there is a better chance for the airflow entering the inlet to become *disturbed* when the aircraft is operating at high AOA, which could cause a compressor stall or surge, or a flameout. Hence the need to prove the aircraft can be airstarted before it begins flight testing in the high AOA regime. The Navy’s Charlie will also require airstart testing before high AOA flight is approved. One operating engine is *always* better than no operating engine. Losing one engine in a twin engined aircraft certainly would cause a yawing (and rolling) moment, but rarely results in a departure except in extreme attitudes and regimes.

    • SirSapo


      A stall in an engine occurs when the blades of the compressor (which are essentially rotary wings) experience an aerodynamic stall like SufaViper described. The issue in the engine is that the jet is relying on the very high pressure generated by the compressor to keep the hot gas from the combustor going out the back of the motor. Once the compressor “stalls”, this high pressure goes away, and there is nothing keeping the hot burned fuel air mixture from going back out the inlet of the engine, rather than the exhaust. This obviously really screws up the flow into the engine and in some very violent cases can flameout the engine, necessitating a restart.

      Sorry if thats too technical of an explanation.

    • Rod

      Thank you all for your insight, especially the more technical ones. My field deals with fluid dynamics, compressors, combustion, and engines but in relatively static systems. I had trouble making that leap of logic.

  • Tribulationtime

    -Triyiing Inglish- How do many years late is the program?. How do many millions aircraft price is reached today?. It Is, right now; over the price of full operational F22?. What do are advantages points of F35 vs F22, head to head?.

    • Chuck

      The price will fall considerably as aircraft buys go up. They are already buing more than the F-22 at its highest production rate (20 a year for the F-22, compared to 30+ for current LRIP buys of the F-35). Factor in inflation of course and it is not too bad really. If production even doubles, we could see aircaft below $100 million. If we buy over 100 a year, we will be well below that figure. Considering the greatly increased capability, it would be well worth it. For all you guys wanting improved F-16s or F/A-18s, consider that adding all the mods you want would greatly increase the price, require a long development period (longer than the F-35 has to complete its testing), and you still have a design that began in the 70s with all the problems that comes with it.

    • tiger

      The F-35 has a different mission. Fighter/Attack over The Air superiority role of the F-22.

      • Tribulationtime

        I know her different “multirole”. But diferent intended purpouse don´t neglect a comparision. A) F-15 derived in F-15E, Can you compare a F-15E with a F-16 50/52 (f-35 will be the susbtitute), in a roughly way Yes. F-18E/F is more focus on attack, Can we compare it (must be) in a fight against a MIG29A.? Typhoon is air superiority plane, today; next tranches adds ground attack features. And go on. The cuestion arise by itself What do f35 better?. Range, stealh, payload, sensors, fly performance, maintenance cost, weapons integration, failure rate, endure damage, speed, fuel comsuption, cheaper sparfe parts from china(joke). What F35 adds to the Global Superpower?

        • Robert Fritts

          Your answer is that the F-35 will not add much to Global Security. Reguardless of all the rosy forecasts by its fans, every quarter LM rolls out its press releases. These releases all have one theme capabilities are ALWAYS reduced , problems and cost ALWAYS increase. The wishful thinking of some, “if we can produce 100 a year the prices will fall” is sophmoric. If we build 35 Aircraft Carriers a year the cost will go down too, but it aint gonna happen.

  • Chuck

    Also, when you think of growth potential, the F-35 has vastly more potential than older F-16s and F/A-18s. As the F-35 is software enabled, it will see much more in the way of upgrades than any other aircraft we have yet developed. And, BlackOwl18E might be interested to note that a twin engine variant with expanded weapons payload is not out of the question. As it would be similar to the F-22 in many respects (interestingly built by the same manufacturer) it would probably be easier to build. Most of the subsystems would remain, with the added engine and larger size being the only differences. Therefore, mission system and software testing would be less difficult, and aerodynamics and some weapons drop testing would be the major requirement.

    • tiger

      Uh, it’s not quite that easy. It’s not like photoshop. A 2nd engine requires a long redesign.

    • Charley A.

      There will be no twin engined F-35.

    • ltfunk2

      LOL a second engine, why not, its not like they havet redesigned the whole aircraft a couple times already .

    • TJRedneck

      Chuck, if there is a possibility for a twin engine variant, then why not just build more F-22s?

  • Mat

    Hi alpha preformance set 4th generation(F16, F15 ) apart from 3rd generation(F4,F104) that was built around faster and higher , 5gen F35 has yet to prove better agility than F15 or F16

  • ltfunk2

    The F-35 is a real shot in the air for all thopse refusrbished MIG-21s out there. Suddenly what was a marginal obsolete fighter has superioir performance to thousands of front line American fighters.

    • William C.

      Superior performance? Yeah, maybe it can go faster in a straight line for a short time before running out of fuel. That should help a lot… /sarcasm

  • TJRedneck

    There are a lot of comments here criticizing the F-35 for not having 2 engines. On the one hand I understand that criticism because obviously 2 engines are better than one. On the other hand, the F-35 supposed to be to the F-22 what the F-16 is to the F-15. I.E. a “cheaper” aircraft that can supplement the F-22 like the F-16 does for the F-15. Problem here is that the development of the F-16 went a lot faster and smoother than the F-35 and the F-35 has turned out to be more expensive than it should be. I DO hope that the F-35 succeeds and turns out to be a great aircraft since we have sank so many taxpayer dollars into the program, so I am happy to finally here some good news.
    Here is the F-35B Sea Trials: https://www.youtube.com/watch?v=Ki86x1WKPmE&f

  • Formerly Skeptic

    One data point missing from the discussion of one versus two engines is the fact that the F-35 was designed from the outset with a vertical lift variant. The normal truism that two engines are better than one is stood on its head when you consider an aircraft which must hover on engine power. The hover transition to landing is a critical phase of flight at which time engine failure guarantees the loss of the aircraft. Unless the aircraft can maintain the hover on one engine, a two engine design doubles the probability of failure. For a smaller aircraft, this drives you to a one engine design. A larger aircraft must rely on other approaches like large engine performance margins and cross-shafting to allow for engine-out operation (see V-22).

  • dee

    A single engine test such as this isn’t new the F-16 has a single engine and would have undergone the same test decades ago.

  • Dave

    It is sad that Navy brass is attacking the single engine concept. Yes, the F4, F14 and F18 were and are successful warbirds. However, there are still other single engine fighters that deserve mention: F8 Crusader, F9F Panther, A4 Skyhawk, F11F Tiger. By the way, the F11F and A4 were flown by the Blue Angels for years.

    Yes, there are cost overruns on this project. If I recall, the F18 had it’s share of mishaps during it’s trials. Is the DoD grabbing for too much in this little fighter? Maybe. Only time will tell.

  • Arthur

    If you watched some of the video’s available, the complete 360 deg situtional awareness lets the pilot know everything going on around him. It allows him to shoot the guy on his tail even before he is seen. The software to do all of this is a magnitude greater that anything that has been done previously.