PROPOSALS SOUGHT FOR THREE ROTORCRAFT SURVIVABILITY TECHNOLOGIES

Date: September 26, 2005

The Army's Aviation Applied Technology Directorate is looking to develop three technologies to improve military rotorcraft and crew survivability, which could benefit Army aircraft.

In a recent broad area announcement, the directorate said it is soliciting technical and cost proposals for three technologies -- a structural integrity monitoring system (SIMS), multifunctional structures for ballistic protection and a space-armor protection system (SPS) -- to support the Defense Department's "Rotary Wing Vehicle Technology Development Approach."

Although funding levels vary with each technology, the directorate is proposing an 18- to 27-month "period of performance" for each, beginning in fiscal year 2006, according to the solicitation. Responses are due to AATD by Oct. 31.

SIMS, intended to enhance the Army's Rotorcraft Structural Integrity Program, should be able to make a real-time assessment of the location and severity of damage an aircraft has incurred, according to the announcement.

"With greater performance requirements placed on Army rotorcraft to be lighter, faster and stronger, airframe structures are being pushed to their limits," AATD told offerers. "In order to ensure aircraft reliability and mission success, the structural integrity of critical components will require monitoring.

"Having a clear understanding of an aircraft's structural integrity will enable the pilot to safely fly within the aircraft's limits as well as notify the crew when maintenance actions are required. This will ultimately improve safety, performance, reliability, readiness, and reduce maintenance time and cost," the notice added.

Accordingly, the directorate tells offerers to examine commercial-off-the-shelf sensor solutions before developing new sensors for the technology.

Currently, AATD has earmarked $900,000 for SIMS development and multiple contracts may be awarded as a result of the solicitation.

Next, the directorate is soliciting proposals for multifunctional structures for ballistic protection -- armor protection -- designed to be integrated on the floor of utility and cargo helicopters, according to the solicitation.

The future design is expected to replace the current floor and add-on armor layer with one component to defeat 7.62 mm munitions, while at the same time being lighter than the current "parasitic" approaches, according to the announcement.

"The U.S. Army has an ongoing interest in developing aircraft structures that protect the crew and critical systems from small arms fire while remaining weight-efficient and affordable," AATD said. "Current parasitic armor has a significant weight penalty that limits range and payload of the aircraft. This weight penalty arises from the use of separate components for the functions of carrying loads (structure) and providing ballistic protection."

Approximately $375,000 is in place to support a contract award as a result of the solicitation, according to the document.

The final technology, a space-armor protection system (SPS), is expected to protect rotorcraft from small caliber threats, but should be 30 percent lighter then the current state-of-the-art steel-based systems, AATD said.

"Because of previous material limitations, the spaced-armor concept has not been implemented on a rotorcraft," the directorate said. "Models to optimize spaced armor performance do not exist in a useful form. Much work has been done to describe the tumbling of a projectile, but most work is for after the projectile has gone through armor."

SPS should consist of a striker plate used to break apart a rotational momentum of the projectile, a space to allow the projectile to rotate or tumble, and a "catcher" component used to defeat and capture the broken and turned projectile pieces, according to the directorate.

For SPS, ATTD expects to fund the technology's development with $300,000, according to the solicitation.

The directorate declined to comment on the proposed technologies.

-- Ashley Roque
INSIDE THE ARMY

Easy.

When 'more protection' and 'lighter weight' are used in the same sentence, hang onto your wallet.

Quoted: Easy. When 'more protection' and 'lighter weight' are used in the same senctence, hang onto your wallet.

Not shit, those are usually mutually exclusive. How about this?? Add ejection seats like the russians did.

Quoted: Quoted: Easy. When 'more protection' and 'lighter weight' are used in the same senctence, hang onto your wallet. Not shit, those are usually mutually exclusive. How about this?? Add ejection seats like the russians did.

That concept always scared the hell out of me.  Maybe they can just eject downwards, like the navs in a BUFF.

Quoted: Quoted: Easy. When 'more protection' and 'lighter weight' are used in the same senctence, hang onto your wallet. Not shit, those are usually mutually exclusive. How about this?? Add ejection seats like the russians did.

yes...eject the pilots right through the spinning rotor blades.  Brrriiiiiiiiiiliant!  

Quoted: yes...eject the pilots right through the spinning rotor blades.  Brrriiiiiiiiiiliant!

What's better, riding a flaming helo into the ground?
I'm sure with computer systems it is pretty easy to time it properly.
Also, why not blow the blades of with explosives a fraction of a second before the seat rockets fire?
I'm sure it would have to be reliable though, because one broken/missing rotor would do horrible things to the aircraft/pilot, kinetically speaking.

Quoted: yes...eject the pilots right through the spinning rotor blades.  Brrriiiiiiiiiiliant!

Another unique Ka-50 feature is the ejection seat - the main rotors are jettisoned before the pilot's seat is ejected.

Quoted: Quoted: yes...eject the pilots right through the spinning rotor blades.  Brrriiiiiiiiiiliant!   Another unique Ka-50 feature is the ejection seat - the main rotors are jettisoned before the pilot's seat is ejected.

Remember, the rotor-jettison system was made by the low bidder.

Quoted: Quoted: Quoted: yes...eject the pilots right through the spinning rotor blades.  Brrriiiiiiiiiiliant!   Another unique Ka-50 feature is the ejection seat - the main rotors are jettisoned before the pilot's seat is ejected. Remember, the rotor-jettison system was made by the low bidder.

A Soviet low bidder even.

Quoted: Quoted: Quoted: Easy. When 'more protection' and 'lighter weight' are used in the same senctence, hang onto your wallet. Not shit, those are usually mutually exclusive. How about this?? Add ejection seats like the russians did. yes...eject the pilots right through the spinning rotor blades.  Brrriiiiiiiiiiliant!

Hello, jett the blades....like was mentioned above. ANything has to be better than trying to autorotate a chopper with no tail rotor, or with one main rotor blade shot away. Fucking deathtraps.

Quoted: Quoted: Quoted: Quoted: yes...eject the pilots right through the spinning rotor blades.  Brrriiiiiiiiiiliant!   Another unique Ka-50 feature is the ejection seat - the main rotors are jettisoned before the pilot's seat is ejected. Remember, the rotor-jettison system was made by the low bidder. A Soviet low bidder even.

Nyet.

The entire craft was developed, designed and built with almost no regard to development cost. The Ka-50 is a truly remarkable machine. Besides, what's the alternative way to get out of a tumbling, burning helicopter? Jump out the window? C'mon. I'll bet some of you don't wear seat belts either, because you want to be "thrown clear" of the wreckage.

The ejection thing can be solved with WWI technology -- just install a chain & sprockets between the rotor and the seat to time the ejection and fire the crew between the blades!  

Aside from the technical problem of ensuring that the blades don't accidently jettison when they aren't supposed to (very minor repercussions if that were to happen...), do you realize how fast the rotor blades spin? to try to time ejection so that the blades don't cut the pilot in half is probably impossible, based on the length of time it would take the ejection seat to pass through the level of the rotors.  

Quoted: Aside from the technical problem of ensuring that the blades don't accidently jettison when they aren't supposed to (very minor repercussions if that were to happen...), do you realize how fast the rotor blades spin? to try to time ejection so that the blades don't cut the pilot in half is probably impossible, based on the length of time it would take the ejection seat to pass through the level of the rotors.

1. The blade jettison system is interlocked with the ejection system. If the blades jettison, the ejection sequence is triggered.

2. The centripetal force on the blades will be more than sufficient for them to clear the cockpit. Frankly, the timing ofthe ejection system in a helicopter so equipped is not significantly different than in a fighter with a canopy that must be jettisoned. The whole thing takes place in a fraction of a second.

I believe that the Kamov helicopter ejection system is as reliable as any ejection system in a modern fighter.

Quoted: Quoted: Aside from the technical problem of ensuring that the blades don't accidently jettison when they aren't supposed to (very minor repercussions if that were to happen...), do you realize how fast the rotor blades spin? to try to time ejection so that the blades don't cut the pilot in half is probably impossible, based on the length of time it would take the ejection seat to pass through the level of the rotors.   1. The blade jettison system is interlocked with the ejection system. If the blades jettison, the ejection sequence is triggered. 2. The centripetal force on the blades will be more than sufficient for them to clear the cockpit. Frankly, the timing ofthe ejection system in a helicopter so equipped is not significantly different than in a fighter with a canopy that must be jettisoned. The whole thing takes place in a fraction of a second. I believe that the Kamov helicopter ejection system is as reliable as any ejection system in a modern fighter.

We don't jettison canopies, they are cut off with det cord.  The timing is critical, and just to complicate things, I'm not sure we know the trajectory of a jettisoned rotor blade - besides the tranlation speed added to the angular speed, the aerodynamics are unsteady in the sense that the blade will present its planform to the free stream causing it to fall like a leaf.  Then to complicate the problem, ejections in attitudes other than straight and level need to be added.

Back to the original topic.

The second and third requests are probably workable with a multi-layer sandwich core built up of materials of different densities - sort of a bullet prism.

The first request is hard to do in any meaningful way - the industry has looked at this problem off and on for years (decades), and there is just too much info that has to monitored in the airframe to make intelligent, useful decisions.  If you could slather the airframe in little strain gages and optical fuses, I'm not sure you will want to carry it and the processing equipment around.

If a comprehensive SIMS is installed on the tail boom and vertical tail of a helo so that the structural health can be monitored for its entire length, then a sparsely distributed system installed around the engine, gearbox, and rotor mast backup structure, it can be made to work if the output is not much more complicated than a message along the lines of "there is a 2 inch hole in the number three frame at BL 20 and WL 165".  If anyone wants a system that can assess the damage and recalculate load factor limits based on a on-the-fly reanalysis of the damaged structure, that is near enough impossible since the possible combinations of damage and failure modes is infinite.

Quoted: We don't jettison canopies, they are cut off with det cord.  The timing is critical, and just to complicate things, I'm not sure we know the trajectory of a jettisoned rotor blade - besides the tranlation speed added to the angular speed, the aerodynamics are unsteady in the sense that the blade will present its planform to the free stream causing it to fall like a leaf.  Then to complicate the problem, ejections in attitudes other than straight and level need to be added.

I don't think that the ejection problem in the Ka-50 is a technical one; it's a practical one. The problem lies in the last sentence of AeroE's post. The Ka-50's mission is low and fast, like the Apache. Chances are, if this ship takes a hit, the craft is going to be at FL000.5 or less, and cooking along at significant KAS in anything BUT straight-and-level flight. Fortunately, the Soviets Russians have very good technology for "Zero-Zero" self-righting ejection systems.

Didn't Bell look into ejection seats for the Cobra at some point?

Quoted: The ejection thing can be solved with WWI technology -- just install a chain & sprockets between the rotor and the seat to time the ejection and fire the crew between the blades!

And if I happen to have a big lunch and the seat miss calculates my weight, and I end up going too fast or too slow through the blades.

Damage Detection system?  Like the loss of control, shrapnel ventilating the cockpit, and the smell of something burning isan't a dead giveaway?

More info:

www.fbo.gov/spg/USA/USAMC/DAAH10/W911W6%2D05%2DR%2D0007/SynopsisP.html

Perhaps the idea of an "escape pod" might have some merit. Instead of trying to get rid of the canopy, take it with you. Then again I might be talking out of my butt.

The Army wants to save two assets - the air crew and the machinery.  Ejection seats are heavy and those excellent Russian seats are extremely heavy; helo's don't like heavy.