posted on Aug, 10 2006 @ 01:53 PM
Actually there are at least two variables inherent to the question of helicopter ejection systems.
First, getting to a point in the envelope where they are most capable of reacting in time to almost any departure from controlled flight with an
auxilliary recovery system.
Second, reducing the number of times where such a system is required as a function of deliberate envelope point or environmental/threat hazarding.
Fortunately, especially in low intensity conflicts which are just about the only area where combat helos still have any true utility, the answer to
both questions is basic:
Standoff And Altitude.
If you are at height, you don't have a terrain or attitude modifier which effects TIME necessary to sever the rotors explosively, remove the cabin
roof or canopy and get the seats going up the rails on a 2-then-1 basis typical for most attack helos before impact with the ground or some obstacle
(or an unbalanced rotor disk striking the tail or cockpit and further destabilizing the craft. Or a wingman being able to leave the proximal danger
zone as the EBolts go off. Among many other 'what if' problems).
Furthermore, trashfire (low caliber AAA and unguided rockets) are much more difficult to aim because there is less angular rate lead reference even as
the projectile trajectories are more effected by ballistic drop and TOF. You are of course more vulnerable to guided threats but these are generally
better dealt with by active defenses than maneuver or masking where randomly encountered (TOF problem again). And the higher you are, the longer the
automated (MLDS) defenses have to see the threat leave the clutter and do something about it with expendables and jamming.
There is a further list of 'enablers' that probably could be applied to further this goal:
1. Compound Propulsion and Lift Augments.
If you have a separate propulsion system you don't need to tilt the disk or the airframe as dynamically to regain speed when maneuvering in close
proximity with any terrain hazard. If you have wings, you don't have to rely on the disk for sole-source lift. Theoretically, you can even further
isolate or cross-shaft render redundant the drive trains to ensure that any given single point failure doesn't compromise BOTH forward propulsive and
main rotor drive empowerment.
2. Fuselage Rocket Boosting or Pararecovery.
If you cannot clear the terrain or the aircraft in time, the only remaining choice is to make the airframe do it for you. While this would nominally
require a rather large explosive motor inside the fuselage (posing it's own risk) the notion of retrorockets and a rocket-drogue canopy might at
least combine to stabilize the orientation of the aircraft while giving it a fairly soft landing (within the fps limits of the crash safe seats
3. Fuselage Air Bags.
Both as cockpit immobilizers to the pilots (protecting them from shattered canopy fragments and collapsing instrument/sighting systems). And as
direct impact and possibly floatation rated external impact attenuators.
4. Mini-Drones and LOAL Powered Attack Systems.
The inherent cost value of a helicopter is such that, today, it is LESS sacrificable than say an MBT. As such you are wiser sending a bullet than the
airframe to investigate particularly an intra-urban fight. Because the concentration of enemy and collaterals is so dense that you cannot choose
sheep or goats but must engage the lot, often for /miles/ in any direction or depth. If said drone also carries a cassette of vertical topattack
grenades which have frag/HEAT/D/A modes then so much the better. But there is ABSOLUTELY NO REASON to pay for a 2 million dollar set of high fidelity
sights (literally made to the same levels of clean-room quality that a satellite is) only to put it nose-first into a hail of bullets costing on the
order of a quarter. Not when you can look at the /back side/ of a target building or terrain feature, by sending a 500 dollar camcorder equivalent
sensor on a direct overflight in a drone. Piss Poor weapons systems are in fact the principle shortcoming in modern attack helicopters today.
5. Replacement Of The Rotors.
I know it's an obvious statement to make but particularly with the arrival of multipost auxilliary propulsion systems able to generate balanced lift
twice or more the individual rating of the individual cruise engine without L+LC cycle reliability and plumbing complexities; it's truly time to
consider whether the multiple mechanical articulations of a conventional (engine + transmission) helicopter are required or wise. At least in the
military, this decision is, I'm convinced, as much based on doctrinal 'tradition' (cough, Key West!, cough, cough) as any real technical
superiority inherent to the penny farthing rotary wing system.
If you can't leave a combat aircraft, you'd bloody well better reduce the number and frequency of datapoints wherein _Highest Risk Exposure
Employment_ doctrine AND _Most Dangerous Aero-Mechanical Failure Point_ (coming off or into the cushion at hover and high rpm) engineering
limitiations to a given configuration come together.
Because, in a helicopter especially, that airframe is effectively both the lifeboat and (the rotors) the circling sharks and any terrain or obstacle
feature encountered at high speed represents a coral reef capable of ripping the bottom out of the hull and bringing you into the teeth of your own