A jet you can spin! Now that's what I call FLYING!

[youtube]https://youtu.be/sQxaOwTpeLM[/youtube]

Well, you can spin just about any jet; it's just that some won't recover above 0 AGL. Just looking at the L-39, it's a straight-winged, sub-sonic, non t-tailed airplane that ought to recover. The fact that it's a jet doesn't mean much other than some jets might compressor stall and flame out.

The same basic airframe with two aft mounted engines would probably be a problem with rotational inertia of the engines, even though a straight wing and no t-tail.

Good video.

In a fantasy world where money is no object, I'd rather have a T-38.

Edit: The early Lears have the same GE-610 engines as the T-38 w/o afterburner, and in a couple of thousand hours of flying with those engines I had zero problems with them; 100% dispatch reliability. But our guys who have flown the T-38 have reported problems, the probable difference being the civilian engines are treated much more gingerly than military training. I much preferred the GE 610's to the later Garrett 731's, personal choice.

The L-39 was a basic military trainer IIRC. I would expect any military trainer to have very stable spin entry/exit characteristics.

@Paul....
Though the T-2 was a jet as you describe and was very stable in OCF conditions.

There have been a coupe of questions about off-field and wheels-up landings in the -39. Here are a couple of anecdotes. And a couple regarding other issues, too.

Somewhere in this thread there is a video of an L-39 that did an off-field landing in a plowed field in Russia. No problem. Pilot standing there with TV news channels running around.

The plane stalls at 92-95 KIAS at gross. (I don’t remember the number off the top of my head) and it is totally controllable all the way through the stall. Plenty of control. If I had a 2000 foot field and control of the aircraft, I would ride it in rather than eject or even jump. On pavement, I have cleared the runway at a taxiway 2000 feet from the threshold. The brakes are fantastic. Yeah, I had some headwind and it was a max performance stop. But that was a measured 1982 feet from the threshold. I touched down at the 100 foot point on the runway. The runway was much longer but I wanted to know what was possible in case I ever needed it. Also, it has trailing link gear on all three gear legs and you can land it very precisely where you want and let the gear legs do their thing., It’s approved to operate off of grass.

Another L-39 had a main wheel depart the aircraft at Bridgeport, CT, as it rotated for take-off. Pilot circled for a long while, burned down the gas, and made a wheels up landing on the foamed runway. The plane needed new flaps and a belly skin. And a safety-wired MLG wheel retention nut. Aside from damage from the fire supressing foam, that was it. I knew that pilot and he said it was a non-event.

Our examiner for the 61.58 ride is a very experienced warbird jet guy. Many on here would know him. Anyway - the first time i did a 61.58 with him he explained that he has a five year cycle he does with applicants. Each year he adds another layer of complexity on the rides and pushes the applicant further. On year 5, he take the applicant up and he has the applicant do spins and recoveries. Very predictable.

Separate issue: compressor stalls. With the AI-25 engine, it’s almost unheard of to get a compressor stall. Even when spinning. It just doesn’t happen. That said, the Cuban Air Force was getting them. It was so unusual and unheard of that the flight test center in Moscow did many flights trying to replicate it. They couldn’t. Spins, tail slides, nothing could produce a compressor stall. They finally figured out that the Cubans were flying them at 50 feet over the ocean, getting salt spray in the engines, and that caused some degradation to the fan blades that allowed the compressor stalls. So don’t do that.

I like the added reliability of our 731 engine. Yes, it’s a single engine aircraft on departure. And most departures we weigh 10,000+/- pounds, Start rotating at 95, lift off at 115, and climb at 180. There’s a window where choices are very limited. But they are in a Mustang or Corsair, too. I would put the 731 up against those engine in reliability. Not to mention the Wright engine in the T-28. If you think about engine safety against those aircraft, it looks pretty good. Also, our engine isn’t “race-tuned” and “turned up to 11.” It’s plane jane as removed from a Westwind II or Hawker. I’m not sure which.

Finally, we have all of our maintenance done at Code 1 Aviation. They are very well regarded and certainly as good as anyone in the US. And I would bet elsewhere, too.

The risk management of operating one of these is interesting. There are things operators can do to dramatically alter the riskiness of flying them. How tuned is the engine? How much is deferred when inspected? Are you maintaining to just get by or do you treat the maintenance budget like you hate your kids and don’t want them to inherit? Are you screwing around down low without deep experience? Are you a cowboy in this and other aircraft? I think these items will make a profound difference on one’s exposure to risk.

Best of luck folks. It has been a fun, rewarding, and interesting experience thus far.

Zeke

One question I have about the 731 engine in L-39's is, how is its longevity when doing aerobatics regularly? The engine wasn't designed for a -4G +8G military trainer, so I doubt it's been tested in that way (by the manufacturer). One day I'll probably need to put a 731 in mine so I hope this question is answered sufficiently by then.

in my research, seems about 25% of the fleet has hot seats. It's some old russian design (I don't know what seat is in it).

The survivability after ejection seems to be low; in the few high-speed aborts I've read about (including the one on this thread that was at PVG), the pilot seems to do better in the aircraft compared to leaving it.

I actually looked at the airframe that went off the end at PVG, it was surprisingly robust and did well in spite of going through the trees. the cockpit was completely intact.

in addition to the inspections, I understand it's very difficult to get pyro that isn't expired.

I'm going to leave my seats cold.

One question I have about the 731 engine in L-39's is, how is its longevity when doing aerobatics regularly? The engine wasn't designed for a -4G +8G military trainer, so I doubt it's been tested in that way (by the manufacturer). One day I'll probably need to put a 731 in mine so I hope this question is answered sufficiently by then.

I know of 3. The jet I'm buying shed some compressor blades, and the pilot landed (successfully) on a levy, in the everglades. Gear down, not a scratch on the plane (the levy was a gravel access road).

the one at PVG that went off the end, through the woods, etc. That guy was ok. Plane was trashed, the fuselage was even cracked at the mid-bulkhead.

there was one in England (maybe Duxbridge? it was a brake failure), that was going to be a high-speed runway excursion. The student chose to eject (and was killed), and the IP stayed in the plane and was unhurt.

as Zeke has mentioned, it has a square wing and lands slowly enough that if you need to land off-field you have a good chance of surviving. It will glide 1.5mi per 1,000'. not. much worse than the TBM (2nm/1,000').

On balance, one of the things I'm coming to appreciate is the robustness of the structure. Very stout, and simple, reliable systems.

The airplane was designed to be "flown by farmers and worked on by children."

I just found this thread yesterday and have thoroughly enjoyed reading it. We got to follow Zeke from a wannabe to an experienced owner/pilot. Fifteen years ago there was one that came into KGNF regularly. It was a really nice airplane, but I never met the pilot and have no idea why he was coming in here for overnights. I do know that he killed himself doing low acro.

I always thought it would be a really nice way to go got D.C. to visit our daughter, but the risk of flying these airplanes is real as all the knowledgeable posters have noted.

One thing not mentioned is the risk of injury from an ejection, assuming you could survive it otherwise, from the gforce of the ejection. I can't imagine the vertebrae of an older person withstanding that without severe injury.

Jg

Sitting position during ejection is vitally important for mitigating compression injuries - certainly worth doing training on during the actual recurrrency.

Flailing injuries during ejection are certainly possible, however, they're somewhat mitigated by the leg straps and position of the handles (center) as well as the generally subsonic / low speeds the L-39 flies. The other thing to note is the ejection seat limits for a pilot (or backseat rider) is 225lbs with everything (helmet, etc) except the parachute. The sitting height is 39 inches max as well. Probably more than a few pilots outside that weight limit.

The actual envelope isn't great, but it isn't terrible either. It's just not really designed for a high sink rate or high dive ejection at low altitude - especially with two people trying to get out (generally if they're both sequenced at the same time, the aft has priority).

L-39's are not FIKI, correct? Does that limit their usefulness for personal transport, especially in winter?

Ian -

You're absolutely right - not FIKI. The windshield, engine inlet lips, pitot/static ports, and fan bullet are all heated. No wing or tail de-ice.

Ice building on the leading edge is visible from the cockpit. That means DO SOMETHING NOW.

I'm a total ice-sissy. And that's ok with me - I can live with that. My partner is a little more aggressive but not hugely so. He flies much more cross country in the plane than I do.

Z.

Assuming that you don't punch out of one or do low-level acro, is there really much increased risk of flying one of these? After reviewing the thread, I think that the trained pilots who posted in this thread debunked many of the myths. For pilots who don't do stupid things, is there increased danger? It's reported to be an airplane with benign handling and a reliable turbine engine.

It seems that the main increased risk of flying one of these XC vs. your Baron or 195 is in convincing Mrs. JGG to climb into one. The cool factor of getting to wear a flight suit and helmet and the allure of getting there twice as fast as your propeller planes may not be as enticing as a comfy first class airline seat and complimentary drinks.

edit: BTW, I'm not being argumentative. I'm just wondering out loud. Megamillions is back up to over half a billion dollars, so when I win it I'll be wondering if an L-39 will be a viable way to get myself across the country to visit Taigh while he builds up my dream Twin Beech.

Assuming that you don't punch out of one or do low-level acro, is there really much increased risk of flying one of these? After reviewing the thread, I think that the trained pilots who posted in this thread debunked many of the myths. For pilots who don't do stupid things, is there increased danger? It's reported to be an airplane with benign handling and a reliable turbine engine.

It seems that the main increased risk of flying one of these XC vs. your Baron or 195 is in convincing Mrs. JGG to climb into one. The cool factor of getting to wear a flight suit and helmet and the allure of getting there twice as fast as your propeller planes may not be as enticing as a comfy first class airline seat and complimentary drinks.

edit: BTW, I'm not being argumentative. I'm just wondering out loud. Megamillions is back up to over half a billion dollars, so when I win it I'll be wondering if an L-39 will be a viable way to get myself across the country to visit Taigh while he builds up my dream Twin Beech.