Ballistic recovery system in jabirus

[David Isaac]

Okay my turn for a dumb question. Okay maybe a couple of dumb questions:blush:Do they customise each brs to suit the weight of the aircraft it will be fitted in?

 

Is there any reason why a bigger chute couldn't be used to slow the descent more?

Yes they are customised to the MTOW and the bridal attachments are customised to the frame type.

Yes a bigger chute will slow the descent but will weigh more. The whole thing is a compromise for weight.

 

With the Hornet just hold the stick hard back and she will descent like a parachute ... LOL

 

 

[kaz3g]

Yes I have seen these seat belt airbags in the exit row of a passenger jet in Australia, I think it was a Virgin flight. Not a bad idea and not that heavy.The greater risk to injury is a poor practice of only wearing the lap belt and not using the shoulder harness. A lot of Cessna pilots have this bad habit.

 

When I purchased my Auster, a few knowledgable Auster buffs suggested strongly that I fit the second shoulder strap to my seat belt so that it becomes a full shoulder harness. The reason they said that most Auster prangs have been survivable, but a few fatalities have been caused by the occupants heads striking the dash area.

 

In my view in a strong slow speed aircraft, quality seat belts and attachments are a better investment and I would definitely look at the seat belt airbag option.

Good seat belts are proven lifesavers.

 

I replaced the lap sash belts in my Auster with new 4 point belts and I am very happy with them. They support me laterally in turbulence or steep bank angles but they also just "feel" right.

 

And you're right, David, the low stall speed and good belts give a high survivability in the event everything goes to crap.

 

Kaz

 

 

[bexrbetter]

Good seat belts are proven lifesavers.

Of course but only if worn/installed properly and a lot don't.

 

I have read a number of light aircraft accident reports where the pilot 'submarined' under the belt, the result which either breaks your neck or cuts your jugular.

 

Many wear 4 points far too high, lowers should come up and over your hips and buckle at your groin not your stomach and of course if you are in a laid back position look into 5 or 6 point belts for submarining protection. Never have the upper belts mounted to your frame behind you lower than shoulders or you risk compressing your spine, i.e. DO NOT run them over your seat and down to the floor behind the seat (unless you are crossing them over a main lateral beam), and of course wear them tight at all times.

 

 

[kaz3g]

Th

 

Of course but only if worn/installed properly and a lot don't.I have read a number of light aircraft accident reports where the pilot 'submarined' under the belt, the result which either breaks your neck or cuts your jugular.

 

Many wear 4 points far too high, lowers should come up and over your hips and buckle at your groin not your stomach and of course if you are in a laid back position look into 5 or 6 point belts for submarining protection. Never have the upper belts mounted to your frame behind you lower than shoulders or you risk compressing your spine, i.e. DO NOT run them over your seat and down to the floor behind the seat (unless you are crossing them over a main lateral beam), and of course wear them tight at all times.

These days my stomach acts as a natural barrier against submarining beneath the lap belt.

 

Kaz

 

 

[jetjr]

So how do you do a 4 point harness into Jabiru?

 

 

[Bob Llewellyn]

Would airbags increase survival rate and reduce injury in jabs during forced landings? It's cheaper than a chute. I am just brainstorming…

If it was big enough to cushion the whole aeroplane! The instrument panel is outside the critical flail envelope. The weight of the units and the reinforced supports - they go off with a bang - would cost fuel. Leaving the tanks dry and making brmmm brmmm noises is very safe

 

 

[Bob Llewellyn]

I have been at Ole's factory a few times, lovely straight up guy and he takes his engineering on the safety side of it very seriously, chome moly frames are extremely robust as is the trailing arm suspension and the intergration of it all. If you're going to have a crash an AAK isn't the worst place to be.He does suffer a weight penalty though for it all.

Crashworthiness costs - and light light aeroplanes have not much margin of useful load. Where does the cost/benefit cut off?

 

 

[David Isaac]

So how do you do a 4 point harness into Jabiru?

I would ask Jabiru that question

 

 

[Guest Andys@coffs]

seems to me that if you use a multi point harness then you need to be very comfortable that in a crash your points of termination for the harness will remain with the bit you are staying in, if they are far from the "cell" in which you sit what happens if the fuse feels the need to separate, suddenly you become part of the "solution" holding the two parts together...I suspect that would hurt!

 

Andy

 

 

[facthunter]

Happens with a Chipmunk. They separate just behind the rear seat, and the harness attach go with it. Nev

 

 

[jeffd]

Anyone ever seen or heard of a BRS parachute installed in a jabiru?I'm thinking I might like to get one if such a thing is possible.

My jab is experimental class so I can do it if I want. Just depends if its possible.

hey jaba i spoke with bryan from brs hear in australia via email not long ago with that question .he told me he had spoken to jabiru and at this point in time they werent prepared or able to devote what was needed to install a brs .however things may have changed so send him an email directly and c what the latest is.

 

 

[Oscar]

Id pay for proper harness in jab, whats the plan?Reducing risk may involve more basic upgrades than BRS or air bag belts or really basic stuff like 1 hr a month practice forced landings

JJ, the plan is to use the existing shoulder and lap harness points, plus add the (fifth and sixth) anti-submarining straps both sides of the throttle lever. That means the main restraint loads will be carried out by the existing points, so no re-working of the structural elements should be required. The plan also includes adding anti-whiplash headrests as part of the shoulder harness mods., and I've been working with a proper aero-engineer on the basics so it all looks entirely possible (at this stage, anyway) and not too dramatic for a Part 21M engineer to approve - but I'm looking to develop it as a basically bolt-in kit, so you'll understand if I don't provide too much more detail. FIA race-approved harnesses meet (actually, slightly exceed in the shoulder-straps) the FAA requirements, and with lightweight cam-lock buckles provide an inverted release capability.

 

We have a heap of work to complete and a rather massive EO to have approved before I can get onto this particular exercise, and I've only been looking at our LSA55 so far, so I reckon maybe 12 months before I have anything to show, but for what it's worth, I've built up a test version and with a 75mm straps-harness, you most certainly feel vastly more 'restrained'. The downside is that you won't be able to access anything in your shirt pockets, unless they are on the sleeves. The standard LSA55 harness points lend themselves admirably to the change-over, but the headrests are frankly necessary to ensure that the assembly does not introduce any new dangers, so while the basic idea is simple, it needs very thorough consideration - and that includes ensuring that one can reach all controls easily when properly strapped-in.

 

 

[facthunter]

What's the "G" loading specified for restraint points? About 20? Nev

 

 

[David Isaac]

Jees Nev, that would tear the frame out of the old Auster wouldn't it ?

 

 

[Oscar]

What's the "G" loading specified for restraint points? About 20? Nev

For aircraft certificated under BCAR S, it's only 9.0 forwards, 4.5 upwards, 4.5 downwards and 3.0 sideways. As you will appreciate, that's not a real lot; I suspect (but state that I have nothing more than a suspicion here rather than fact to support the contention) that the nature of the Jab. primary structure provides a fair amount of 'boing' flexibility that reduces the ultimate occupant shock load at impact on the harness points. As we all know, it's not just actual loads but the rate of rise of the application of the load that is important and your chances of injury are magnified if you are being tossed around unrestrained...

 

 

[jeffd]

For aircraft certificated under BCAR S, it's only 9.0 forwards, 4.5 upwards, 4.5 downwards and 3.0 sideways. As you will appreciate, that's not a real lot; I suspect (but state that I have nothing more than a suspicion here rather than fact to support the contention) that the nature of the Jab. primary structure provides a fair amount of 'boing' flexibility that reduces the ultimate occupant shock load at impact on the harness points. As we all know, it's not just actual loads but the rate of rise of the application of the load that is important and your chances of injury are magnified if you are being tossed around unrestrained...

have u heard any other news regarding brs systems for the jabs oscar.a fellow i speak to from sth australia on facebook has a 160 is upgrading or changing over from another type,and has had no problems with his motors and is very happy with the aircraft.my interest in the brs is purely from structural failure ,collision etc side of things

 

 

[Guest Andys@coffs]

Between the legs throttle mount.......I'm guessing there is some serious redesign required there to support the arresting of 9G of forward acceleration of a pilot for a component that if subject to 9G might just about top 1G equiv of 5Kgs...if that.

 

Andy

 

 

[turboplanner]

What's the "G" loading specified for restraint points? About 20? Nev

ADR3 specifies 20g for 30 milliseconds in cars, but I'd suggest winding it right up to what the brain can stand, and it would be worthwhile considering a five point harness, it takes very little extra time with a quick release buckle.

 

 

[Oscar]

have u heard any other news regarding brs systems for the jabs oscar.a fellow i speak to from sth australia on facebook has a 160 is upgrading or changing over from another type,and has had no problems with his motors and is very happy with the aircraft.my interest in the brs is purely from structural failure ,collision etc side of things

Jeff, I have exactly zero information about installing a BRS in a Jab., so can't help you there. However, I do know that some serious work is being done to establish the fatigue life of (I'm pretty sure) the J160 at the moment and that should be finished fairly soon, I believe. As far as I am aware - and Jab. are really the people to be handling this, or at least the various regulatory bodies around the world responsible for aircraft safety, apart from one possible case in France that has been speculated as having a number of causes, there haven't been any significant structural failures in Jabs. Collision - yep, I agree, a BRS is the only option.

 

Between the legs throttle mount.......I'm guessing there is some serious redesign required there to support the arresting of 9G of forward acceleration of a pilot for a component that if subject to 9G might just about top 1G equiv of 5Kgs...if that.Andy

Andy - in my idea for installing a six-point harness, the only load on the cross-beam the throttle mounts on would be the anti-submarining straps, the actual lap restraint points would remain the original ones. I've only looked at anLSA55, so I can't comment on how this idea might fit into other model Jabs., but in the LSA55 construction, at first blush it appears a viable arrangement. However, it is very much something of a work to be 'in progress' sometime in the future and I'll be working it through with a Part 21M engineer who knows the LSA55 structure in every detail, so iot certainly won't be just a case of drilling a couple of holes and hoping for the best!

 

 

[facthunter]

I'm not going to list the downsides of a BRS They are widely commented on. so you can do the research IF you want to. Some mid air collisions will be such that you may be already dead and at low levels it is not much use, either. Boeing and Airbus don't use them. Nev

 

 

[jeffd]

that is true about the collision side of things for sure.i havent heard of any jab 160s falling apart but am interested in looking up bad incidents of the brs ,knowledge is good to have,and of course engine out on any aircraft doesnt mean an immediate pull the cord response.

 

 

[turboplanner]

that is true about the collision side of things for sure.i havent heard of any jab 160s falling apart but am interested in looking up bad incidents of the brs ,knowledge is good to have,and of course engine out on any aircraft doesnt mean an immediate pull the cord response.

I just dialled up ATSB reports and clicked Amateur Built in the "Aircraft" field, and typed BRS in the "Event Details" field

 

That brought up about 30 reports, and in the first fatal the aircraft was fitted with a BRS but it hadn't been armed. I think they said it wouldn't have made any difference, but I've certainly read a number of reports where the BRS hadn't been armed or was found to be permanently wired in safe position.

 

That in turn reminded me of a few more accidents with visitors, spectators, maintenance staff etc who set off the BRS unintentionally.

 

There were other cases I recall where the aircraft was not positioned to allow the BRS to work.

 

If after searching the NTSB database as above you switch the "Aircraft" field to All you'll pick up Cirrus accidents and other production aitcraft

 

 

[dazza 38]

that is true about the collision side of things for sure.i havent heard of any jab 160s falling apart but am interested in looking up bad incidents of the brs ,knowledge is good to have,and of course engine out on any aircraft doesnt mean an immediate pull the cord response.

I agree, jabs are fitted with engines made of crystal, but they make a fantastic airframe.

 

 

[jeffd]

the airframes do seem to b popular and homegrown as well .there seems to b alot of people who like the 160 as a good compromise between them all

 

 

[Old Koreelah]

...i havent heard of any jab 160s falling apart but am interested in looking up bad incidents of the bra ...

Sorry it's only heresy, Jeff but I have heard of a low-wing aircraft which fired it's BRS and landed on water with serious injury to the pilot. Arriving vertically on water is like hitting concrete. The BRS depends on undercarriage to absorb a lot of the impact.