Are there any helicopters with ejection seats? If so, how is the clearance problem with the rotating blades solved?
3$\begingroup$ First you blow off the blades, then the canopy and last the seat. $\endgroup$– Peter KämpfAug 28, 2017 at 14:17
1$\begingroup$ @PeterKämpf And hope you don't get an unwanted haircut. :) $\endgroup$– Juan JimenezJun 12, 2019 at 11:55
Many years ago I read about the Kamov-50 helicopter family* being the first helicopters equipped with ejection seats. And Wikipedia verifies my memory:
It is the world's first operational helicopter with a rescue ejection system, which allows the pilot to escape at all altitudes and speeds.
In the same article for the same helicopter it is mentioned that
Before the rocket in the ejection seat deploys, the rotor blades are blown away by explosive charges in the rotor disc and the canopy is jettisoned.
Also, if you want to count experimental helicopters in, Sikorsky S-72 RSRA may be another one. Here is an interesting video, demonstrating the blades being blown away, and ejection of the pilots.
As a side note, in the article I read in an aviation magazine many years ago, it mentioned a synchronization of the seat with the blade rotation so that the seat passes between the blades. It was based on a working principle similar to the middle machine gun that some WW2 German airplanes were equipped with that fired the projectiles between the propeller blades.
Judging from the fact that I read it somewhere in the late 90s where the project was still new and developing, as PlasmaHH pointed out, that was probably more a thought rather than a fact.
* Kamov 50 and its variants/successors like Ka52
9$\begingroup$ The Ka-52 (the Ka-50s successor) is equipped with ejection seats too (Swesda K-37). I can't imagine that the "shoot through the blades" was more than an idea, given the necessary speed for that (which results in a probably very unhealthy acceleration). Similarly there was once the idea evaluated to reinforce the seat so that when it collides with the blades will protect the pilot(s). $\endgroup$– PlasmaHHAug 28, 2017 at 9:35
8$\begingroup$ To do some math on the blade sync, getting a 1m high sitting human through blades going past at 300 RPM, twice per rotation, 10 times a second, requires a speed of only 10m/s. An acceleration calculator says a 5g acceleration would give that speed with only 1m travelled. I think there's enough margin that this could work at least in theory. $\endgroup$ Aug 28, 2017 at 11:26
9$\begingroup$ Does the downvoter care to explain? Or I'm asking for too much? $\endgroup$ Aug 28, 2017 at 11:40
1$\begingroup$ That comma in the first Wikipedia quote feels dodgy. Does a rescue ejection system in a helicopter necessarily allow escape at all altitudes and speeds? Or is this the first that had a rescue ejection system which had the property of allowing such escape? Or what? IIRC at least in fixed-wing aircraft, some (particularly earlier generation) ejection seats required a minimum altitude to be safe (for whatever definition of "safe" is in use) to use as the parachute needed time to deploy and slow the pilot to a safe landing speed, while keeping initial accelerations survivable. $\endgroup$– userAug 28, 2017 at 11:52
3$\begingroup$ What you need is an old-style crop-dusting helicopter. No ejection seat required - there were no doors at all, to maximize visibility sideways and down. You checked your seatbelt very carefully before takeoff! (I've flown as a passenger in one of those, doing some aerial photography - scary, when you are hanging out of the door to get a better field of view and the pilot banks 30 degrees to make a tight turn! $\endgroup$ Aug 28, 2017 at 13:02
The Sikorsky S-72 Rotor Systems Research Aircraft had ejection seats, as shown on this video. Like the Ka-50, it blew the rotor blades off first before ejecting.
This article mentions a crash of a Mi-28 in which one pilot died:
The Mi-28 was supposedly designed with an ejection seat system that fires its crew out the side and downward.
7$\begingroup$ Out the side?! Surely that wasn't fully thought through... how would it not instantly break your neck? $\endgroup$– J...Aug 28, 2017 at 13:37
2$\begingroup$ @J... Yeah man, doesn't sound right, no wonder if it was never implemented. $\endgroup$ Aug 28, 2017 at 16:41
$\begingroup$ Firing down isn't particularly good for low-level ejection. :( $\endgroup$– FreeManDec 10, 2020 at 17:21
As others above have stated, the Kamov KA-50 family is fitted with an ejection seat. First the blades are separated from the blade sleeves, which remain attached to the mast (rotor hub). a few fractions of a second later, the conventional upwards firing ejection seat is launched, using extraction rockets tied to cables to drag the seat clear of the airframe.
This cutaway image shows it to reasonable effect. '46' indicates where the blade separates from the sleeve. The little sketch of the smoke on the lower right blade shows the separation, and the '18' and '19' show the extraction rocket. KA-50 Cutaway image
Digital Combat Simulations's (DCS) line of computer simulations models the ka-50, including the ejection seat. I'm sure there's video from the game online somewhere.
1$\begingroup$ I guess we don't have to worry about one of these landing itself in a cornfield after pilot ejection (as happened once with an F-106)... $\endgroup$ Dec 10, 2020 at 14:49
The Mi-28 doesn't actually have the ejection seats, the Mikoyan constructor bureau follows a different approach: they've created energy absorbing seats and landing gear to protect the pilot in a crash.
Kamov does install ejection seats in their helicopters, a.o. in the Ка-52. It blows off the rotor blades and shatters the upper glass windows to make the way clear for pilot ejection. One can see the white cord with explosive on the upper window of Ka-52 on the pictures (there is a white zigzag-like cord on the bottom of the pilot window):
Testing of the part of the system
3$\begingroup$ What is "..amortization for seats and chassis"? $\endgroup$ Aug 29, 2017 at 5:55
1$\begingroup$ I would imagine he meant armor. $\endgroup$– DavidwAug 29, 2017 at 6:15
1$\begingroup$ @Davidw Ah, that makes sense. $\endgroup$ Aug 29, 2017 at 6:54
2$\begingroup$ Nope, it is not about armor. Check out chassis of Mi-28 in the message above, it has pretty developed amortization part : hydraulic\pneumatic cylinder is attached to each of front chassis. In publications it is stated that combined with others impact absorbing elements of construction it should reduce the impact to "physiologically acceptable" level for speeds up to 12 meters per second. Additional concerns are rise against fire safety for fuel tanks (no such separated system develped in russian helicopters yet). $\endgroup$ Aug 29, 2017 at 21:07
2$\begingroup$ Heh, just realized that I use wrong term chassis for landing gear. I actually meant front landing wheels of Mi-28, not the armored capsule. $\endgroup$ Aug 29, 2017 at 21:28