Parachute for Choppers!!!

[genius747]

I am thinking of a new idea for helis...

What about having a parashute being deployed from the center of the rotors if the engine should fail so as to bring the chopper down to the earth safely.


Has this idea been done before or does anyone have any ideas why it would or would'nt work.


Any advice appreciated.

[Twisted Rigging]

Given the choice of a controlled autorotation, or a 'chute?

I'll chose an auto thanks.

I assume the rotor would have stopped!! before the 'chute could be deployed?

[RDRickster]

Does anybody else get a shudder when someone refers to a helicopter as "Chopper?" ;) Anyway, I believe this was investigated by the Army decades ago and moth-balled. I'm sure Lu Z or Rich L can elaborate more. Try contacting the folks below and see if they have any records available...

U.S. Army Aviation Safety Board (http://155.147.98.10/abso/index.htm)

I don't believe it would be practical. There are too many variables that you would not be able to control in an uncontrollable situation. Also, the blades would need to be at zero rotation less they steel air from the canopy or get tangled in extreme attitudes.

I guess it would be practical if ship were in blow-back where the helicopter is a giant lawn dart! Also, speaking as a former Jump Master, the aerodynamics and capabilities of parabolic parachutes are limited. Too much airspeed or weight when deployed, and you will rip the gores right out of the package. If the helicopter experiences complete failure with blow-back, the kenetic energy created with mass and speed will be too great - - even for ballistic heavy drop parachute configurations.

Besides, these types of parachutes are complicated... and they don't always work! I can't tell you how many times I've seen a jeep or a tank burn in... amazing site. Small systems for LIGHT fixed wing aircraft and ultralights are successful because they don't need to be complicated and weight isn't as much a factor. What you propose is quite the opposite. Good luck!

[Genghis the Engineer]

The word "chopper" is probably quite apt in the context - unless the design is utterly foolproof it's probably what will happen to the parachute !


I've flown with light aircraft systems a few times, and dealt with the design of a couple of trial installations. Whilst I agree that they're pretty simple, they're also remarkably lightweight. Something like this (http://brsparachutes.com/PI_modeltypes.mgi?container=1500+Softpack) would handle the speed and energy (if not the rotor) of a typical small helicopter and masses 34 lb.

You could blow the rotors off of-course, but that's arguably a little extreme.

G

http://brsparachutes.com/resourcespi/CirrusSR20_2.jpg

[RDRickster]

Take a look at this...

http://www.helis.com/types/comultra.php

Click on "Eagle's Perch" in the middle of the page (scroll down). The Eagle's Perch is a twin engine, coaxial pendulum kit helicopter with no tail rotor. Original concept was for Ag spraying, pipe line inspection, and mustering cattle. The blades are made of wood.

The aircraft can maintain flight on a single engine, but it cannot hover without both engines running. There is a ballistic parachute to provide an extra margin of safety.

In an emergency, a steel chain (attached to a parachute) is shot from the aircraft. When the parachute deploys, the wooden blades are cut off from the rotor head by the steel chain!

Okay, who wants to be the test pilot for this one?

[ShyTorque]

Why would a parachute be better than an autorotating rotor system anyway?

It would be non-controllable at the bottom of the descent in any event and result in a firmer touchdown than a properly flown auto. :confused:

[Flight Safety]

A rotor system makes a great alternative to a parachute. It has controllable lift, can be easily steered, and allows forward speeds far higher than a parachute thus allowing for greater flexibility in choosing a landing sight.

[Flytest]

This post reminds me of my time in the Royal Navy, we actually took delivery of parachutes for Merlin crews, apparently due to loss of tail rotor drive in flight. The idea was that above a certain height, if something catastrophic happened, you stopped the main rotor and got the hell out.

Nobody actually cared about the ship, thats replaceable.

To the best of my knowledge, the system was never used.

[ShyTorque]

I heard that the system WAS used.

Some of the pilots parachuted right out of the Navy. ;)

[bugdevheli]

In view of the fact that light rotorcraft appear to chop their rotors into the tails more often than more robust machines,and given that in most instances either one or both blades depart the aircraft. Would not a ballistic chute be a nice thing to have? Even if shot from under the belly! Coming down upside down is surely an acceptable option to the alternative.

[Genghis the Engineer]

The device itself would mass around 20kg (50lb) and could be mounted below the aircraft - that's achievable. Certainly they exist for much higher inertia aircraft than an R22. Costwise, you're certainly looking below £6k/$10k, which isn't a great deal compared to the cost of any helicopter.

Operating it could be solved in a similar way to the Yak-38 "Forger", a Soviet harrier copy that sat on a tripod of three gas-turbine engines. If you lost a single engine (I'm not sure how this was sensed, but I'd guess a comparison of N1 values combined with a weight on wheels switch) the ejection was automatic. I believe that the red-navy's record was that about 2/3 of their (fairly large) number of Yak-38 ejections were automatic. (Must be a bit of a shock to the system, but better than the alternative).

In a helicopter, an RPM drop sensor combined with a weight-on-skids switch would probably do the job and be fairly easy to mechanise.

A much more difficult problem may well be the integrity of the suspension loom. It's fairly common in FW applications to mount the parachute and it's ballistic drogue in a canister below the belly of the aircraft. But, then the suspension loom needs to be routed round the side of the aircraft to a suitable attachment - in an R22 I'd venture that the gearbox assembly would probably be that. So, the chute fires out the side, swings round the top, and the aircraft then descends to impact on the wheels or skids - the only bit of structure designed to take a hard ground impact without killing the occupants. The fact is however, that this loom will have to be man-enough to take impact with the rotor without being weakened sufficiently that it breaks under the shock load of a falling aircraft at one end and an opening parachute canopy at the other, or without being wrapped into a still rotating rotor and bringing the canopy in with it. There are looms available that will go through a rotating propeller and survive - but a helicopter rotor is a much more daunting prospect and this would be an "interesting" engineering problem to solve.


So, I think (and incidentally, I'm the bloke who wrote the UK's civil rules for fitting these things onto FW aeroplanes) it's possible.



The other question is - is there any point? As has been pointed out, a competent helicopter pilot should be able to auto to the ground anyhow. If the aircraft is routinely operating over terrain where this isn't feasible - say forrested mountainside, shouldn't they be operating a multi-engine helicopter anyhow? Of course it would save your bacon in the event of a structural failure of, say, a main rotorblade - but is that a realistic risk that needs to be guarded against?

In the fixed wing world, there are two main environments that they are used in - the Cirrus which has never been shown to recover from a spin, and in German where it's mandated for microlights (but their structural rules are such that structural failures are I'm afraid quite common). Most of the rest of the world either has high enough structural standards, or insists upon a spinning evaluation, or both. I'd regard any suggestion of fitting ballistic parachutes to helicopters in that light - where's the need?

That said, they have their uses. In light fixed wing flight testing (my mastermind specialist subject) it's an elegant safety solution for high risk trials such as stalling or spinning of a new prototype. But the occasions where they are really a good idea are few and far between.

G

[Col]

I've thought about the parachute thing too. Also thought about wings that could be instantly deployed in emergencies. How about some kind of sprung loaded, telescopic assembly shooting out either side from underneath the aircraft? Might it create enough lift to glide down?

(Then there's always the anti-gravity machine to install...)

We know that flying rotorwings is inherently unstable but it would be interesting to know if any 'slightly unorthodox' safety features have been tried and with what results.

[zeeoo]

hi everybody, i apologize in advance for my Frenglish, "tolerance is the policy of the brave" ;)

i m a "dreamer" dreaming in building my own chopper, i ll tell more if someone is interested.

i m also on rotaryforum, for gyros, and rised the subject of BRS parachutes in a gyro.

it appears that no one can agree about it s real utility, its mounting and deploying...

mast mounting ? useless if buntover, or inverted position.
at low altitides... quite useless..
tail mounting ? could be ok

personnally i believe a parachute should be mounted in front, but fired from side, makin heli have a kind of "flat spin" and landing it on the tail, the tail acting as a shock absorber...

thank you

victor

[Genghis the Engineer]

I'm told that a Larry Neal in Texas had a BRS fitted onto a tandem Air-Command at some point (personally I'm not sure I'd fly an Air Command with a chute!, and certainly not without). I know no more than that, but it might be worth seeing if you can track him down.

I disagree with you about descending onto the tail - the whole aircraft structure is designed to absorb loads when it comes down on the maingear, and redesigning other parts for the same purpose is just going to add weight and complexity for no good reason.

G

[RDRickster]

http://www.pprune.org/forums/showthread.php?s=&threadid=110714

[Col]

Apparently, Nick L knows test pilots who've bailed out of uncontrollable machines...

I think the point about parachutes is for when an autorotation isn't possible.

As for making the airframe stronger should the aircraft land on it's tail, wouldn't it make sense to have it act as a crumple zone, assuming the chute had slowed down the descent to acceptable levels?

(sorry to bring this back up, posted the above in more recent thread)

[Col]

Apparently, Nick L knows test pilots who've bailed out of uncontrollable machines...

I think the point about parachutes is for when an autorotation isn't possible.

As for making the airframe stronger should the aircraft land on it's tail, wouldn't it make sense to have it act as a crumple zone, assuming the chute had slowed down the descent to acceptable levels?

(Posted above in old thread by RDRickster... oops!)

[zeeoo]

hi Gengis an others, thank you for discussing.
hi rickster, sorry, i m new here, and dint see the previous thread

here is the thread i picked from Rotaryforum
http://www.rotaryforum.com/forum/showthread.php?t=2261

as you can see it was a yes-no debate more than a finding-solutions one

you said the airfrane is designed for loads under the mast... ok, but a chute can have several strong wires drowed in the airframe and linked to the strongest part of the frame, ok it sould destroy or deform cockpit but i still thinking like Col the tail is a perfect crumple zone and while the shock, pilots and occupants are lying on their back..

i must say i m not an engineer, so sorry i m just an enthusiast

thank you all

[zeeoo]

re : hello world, i apologize for my bad Frenglish
i m inerested in chutes in a gyro or ultralight choppers,
i m a mad dreamer :} who plans to build one, ok ok dont throw stones please, i have a full truck of them

as you can guess, i d like to have a chute if someday i plan to test any rotor aircraft.

so i must precise this : i think on a chute in extreme cases
avoiding autorotation like :
loss of a blade, structural failure, tail failure, mast bumping, destructive vibrations, flip in wind gusts , and others
, ok autorotation is better than a chute, when you can....

as i said in the other thread, i wonder if the chute could no be fired from the nose, sideways, linked to the strongest part of the airframe by steel wires (drowned in the fuselage), then this would create a "violent" flat spin but keep away the chute wires from the rotor, put the chopper in a nose-up attitude and land it on the tail that could act as a shock absorber...

another question, is there a model of BRS or other chute specially designed for mast mounting?

just throwing hairbrained ideas :}

thank you
victor

[Bomber ARIS]

...I seem to remember a "bunch" of FTEs and TPs bailing out from one of the prototype Merlins that crapped itself at altitude - all survived.

P.S. What IS the collective (no pun intended) noun for a group of our Test Pilot/ Flight Test Engineer buddies?........answers on a postcard, please.

[Genghis the Engineer]

I'm not sure much is in the public domain on that incident (although I seem to remember a good write up in Mod(PE)'s, "feedback" circa 1998), but it happened just as it was being proposed to remove the requirement for flight test crews in helos to carry parachutes - since nobody had ever used them. That particular proposal has, unsurprisingly, not seen the light of day since.

You were probably looking for something more frivolous, but either a "crew" or "department" are the usual collective nouns for TPs and FTEs.

G

[Lu Zuckerman]

Apparently, Nick L knows test pilots who've bailed out of uncontrollable machines...

Lu Zuckerman also knows a test pilot that bailed out from a helicopter. He was a Sikorsky test pilot and his name was Obie Blanchard. He didn't survive as he got caught in the spinning rotors when the falling helicoter flew into his shroud lines.

:sad: :sad: :sad:

[Dave_Jackson]

The parachute didn't work in another instance. The mechanic bail out but it was fatal for the test pilot, Dave Driskill, America’s first licensed helicopter pilot. It was also fatal for the Kellett helicopter company which "never recovered from the dire financial straits caused by the crash."

Intermeshing - Kellett XR-8 & XR-10 (http://www.unicopter.com/0896.html)

[ShyTorque]

Baling out? Used to be an RAF requirement to carry chutes in helis if going above a certain altitude (10,000ft?) - they once suffered a catastrophic fire in a helicopter (magnesium skinned Wessex I think it was) that burned out before it landed in autorotation.

However, I went completely off the idea of baling out as soon as I read the abandonment drill in the Flight Reference Cards for the Whirlwind 10.

There was a caveat at the bottom of the same FRC page which said words to the effect that "Warning: objects jettisoned from the aircraft in autorotative flight may contact the main rotor blades".

:\

[NickLappos]

Doesn't there come a point where you stay home if you can't trust the primary structure of your flying machine?

Stated another way:

Assuming that the parachute for the aircraft weighs 150 lbs (a real challenge) how much stronger and safer would the rotor be if you put that weight into the helicopter to make it stronger and safer to begin with?

Or a third way, If the spare tire in your car cost you a passenger would you carry one?

[BoeingMEL]

Speaking with some humilty but with a few thousand hours of rotary time (including poxy piston jobs) and several hundred para-jumps, this is a dozy idea..... always has been and always will be. On the other hand, why not secure marshmallows to the skids to soften the impact of EOLs? Sorry..... someone's having a laugh! bm

[Reefdog]

WHAT A CRAZY IDEA

SPEAKING AS SOMEBODY WHO HAS SUCCESSFULLY AUTOED A 206 AFTER ENGINE FAILURE WITH A 100' LINE ON WITH 400KGS OF WATER IN IT...... GIVE ME AUTO ANY TIME
YOU HAVE FULL CONTROL EVEN AT 85% ROTOR RPM

MAN DOES THAT RRPM DROP QUICK...........................

[Dave_Jackson]

Nick,

The start of your post make good sense, but this last sentence is a little worrying.

"Or a third way, If the spare tire in your car cost you a passenger would you carry one?"

You're not suggesting that the extra passenger could be tied around the wheel rim, if the tire fails.

Are you :confused: :confused: .

:D :D

Dave

[Lu Zuckerman]

To: Dave Jackson

It all depends on the urgency of the trip and who the passenger is.

:ok: :E :E :ok:

[Dave_Jackson]

Emergency parachute system for helicopters

Published Application 20050087652, Dated April 28, 2005

[ConwayB]

I seem to recall a trial for ejection seats for helicopters back in the '70s. The rotorhead was designed with explosive charges on the blade roots to shed the blades in unison at the 3 and 9 o'clock positions This was for a four bladed rotor with blades 1 and 3 being shed and then 2 and 4 as soon as they reached the same point.

Once all the blades were gone and without the pesky rotor disk ready to "CHOPPER" your head off, the Martin Baker ejection seat did its job just like in planks. I would guess that the same system, if it was plausible and viable, could be used... by why bother?

In my VERY humble opinion and being a Chinook driver with a number of parachute jumps under my belt, I'd only bale out of a Chook if I could take a very fast running jump down the cabin and dive off the ramp past the aft rotor...

Otherwise my choice is to take the baby all the way to the ground.

Here's hoping we are never in a situation where we are thinking that a parachute would have been a good idea.

CB

[tecpilot]

Apparently, Nick L knows test pilots who've bailed out of uncontrollable machines...
I seem to remember a "bunch" of FTEs and TPs bailing out from one of the prototype Merlins that crapped itself at altitude - all survived He was a Sikorsky test pilot and his name was Obie Blanchard. He didn't survive as he got caught in the spinning rotors when the falling helicoter flew into his shroud lines.

Up to the reunification in the East German Airforce all helicopterpilots weared chutes and all pilots performed a complete chute training each year including jumps from helicopters or planes. As argumentation was said an increased safety on IFR flights and in case of technical problems with the controls, hydraulics, blade or gearboxfailure or fire on board.

In 1976 a helicopter acted in 1000ft as a training target to fighterjets. One of the jetjockeys was really hot and dropped below the safety distance and height to the helicopter. Short a midair with 2 chutes on the blue sky and a big firework on the ground from the downed and burning jet. On one chute was the ace and on the other the helicopter PIC. The helicopter was hitted on the main rotorblades and lost some outer bladeparts. The normal result was a tumbling and heavy vibrating chopper, in deep trouble to disintegrate complete in the air. The PIC ordered the crew to an immediate rescue parachute jump, dropped his sidedoor and out he was. The copilot dropped also his door and was going to jump, but in this moment he was gripped by the engineer. This SOB was searching for his chute because he feeled to be on a pleasure flight and wasn't linked to his chute, again orders. Thats more comfortable! The copilot was able to sail down the fluttering and nearly uncontrollable ship to mother earth in one piece but that was changed in several loops on the ground. All 4 soldiers survived only minor injured! Against rumours the fighterpilot wasn't awarded for an airvictory.

Today helicopters are much more improved. But with an old ship in case of an complete electrical failure on IFR or engine failure in the dark night, i would prefer the chute.

[Graviman]

Hmm, good thread. Ghengis has a good point, regarding automatic entry into auto:

"In a helicopter, an RPM drop sensor combined with a weight-on-skids switch would probably do the job and be fairly easy to mechanise."

I'm all for reliable auto pilot safety aids...

Haven't done it for a while, but i used to enjoy gliding. Wind gradient often presented fun on "extended" approaches. Pretty much everyone i knew had a "heavy landing" story, i'm afraid i'm no exception :} . Stall speed (what's that? :confused: ) was about 40, so low energy stuff - but i often wondered if an airbag would help to keep the options open. It's webbed now so ya caint patent it! :p

In a heli it could double as a buoyancy aid for forced single-eng VRF sorties over water, but would be ideal below the H-V curve. The best trigger i thought of was an altimeter activated ground dopplar radar or sonar. The best design a multicelled bag, with pressure relief tearouts. It assumes that the aircraft gets to the ground in fairly large chunks, under vague control.

I'm curious as to R22 muster pilots views on that one...

Mart

[slowrotor]

Gravimans suggestion for an airbag makes more sense to me. Think of the guys that went over Niagra falls in a barrel and survived. Maybe advanced crash structure as in all modern cars is the way. Structural steel that absorbs the impact in a progressive manner. Parachutes only work if you are at some altitude, crashes often occur with little warning.

[tecpilot]

Russian technology one step behind western?

The Ka-50 is the world's first operational helicopter with a rescue ejection system, which allows pilots to escape at all altitudes and speeds. The K-37-800 Rocket Assisted Ejection System is manufactured by the Zvezda Research and Production Enterprise Joint Stock Company in the Moscow Region. The seat operates by pulling the pilot from the helicopter cabin using a solid-propellant rocket motor. The system comprises the seat, a control unit and a pullout rocket motor. The seat is fitted with a survival pack containing an NAZ-7M survival kit, a life raft and a PS-37A parachute system. The seat provides safe forced emergency escape from helicopters in the speed range 0 to 350 km/hour and at altitude 0 to 6,000 metres. The seat also provides safe ejection during inverted flight (at speeds 0 to 330 km/h with zero vertical velocity) at a minimum altitude of 90 metres. Pilot is ejected in max. six seconds.


http://www.military.cz/russia/air/helicopters/Ka_50/images/big/hokum26.jpg

[Graviman]

"...advanced crash structure as in all modern cars..."

Actually the whole thing started when an aviator (Hugh DeHaven) survived a mid-air collision, and wondered why his opposite number didn't....

I certainly think that perhaps it is time to at least investigate design for crash survivability in light aircraft / helos. Amusingly, i spent some years as a crash design engineer (specialised in simulation, Rover 75) - interesting stuff, but not engines. Basically the biggest problem becomes how to package air! You need crush space to deccelerate "occupants" from impact speed to zero, while staying below 40g (assuming well restrained) - this is why you can generally wave your hand around the engine bay in NCAP compliant cars (ignoring plasticky stuff). The really clever bit is to have structure that is light, deforms progressively, and doesn't go to pieces if overloaded - this way even a real bad'un gives the guy a fighting chance...

At an interview with BAE, i was genuinely suprised that wings were not tested to absolute failure - i know of one 747 incident where crew pulled 7g out of a dive, but still landed one banana shaped Boeing...

Mart