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!!!!!

    • 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

  • 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!

  • 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!”

  • 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.

  • 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…..

  • 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?

  • 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.

  • 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.