Low wing aircraft and bubble canopy's?

[onetrack]

I'm often surprised at the lack of interior finish and poor design in many RA aircraft - interiors that could be easily upgraded to offer a much higher level of body protection when you hit it in a crash, if more padding was added and angular shapes rounded.

If you take a look at the HK Holdens, they were the first Holdens to offer a real "driver and passenger safety" design. Simple things such as better dash padding, elimination of sharp edges in interior fittings, a blunt gearstick knob, breakaway interior mirror, and so on.

Many injuries from crashes are the result of the body coming into heavy impact contact with dangerous sharp edges and unforgiving attachments and controls. It's surprising the number of people who were impaled on sharp-pointed gearsticks in prangs in earlier days. Solid steering shafts that were driven through the steering wheel to impale the driver, led to the now-standard collapsible steering column that we take for granted today.

 

I'm sure that with a little more thought, many RA aircraft designs could be easily upgraded with safety padding (including instrument panel padding) that would lead to better survivability for RA pilots and pax involved in forced landings.

I see many instrument panel edges on current RA designs that look like they belong to 1920's models, as regards sharp edges and a lack of padding.

Of course, if your impact speed is high and the angle of arrival is steep, then no amount of safety features will save you.

[skippydiesel]

In an aircraft (especially a small one) stall speed is a good indicator of survivorbility. The lower the stall the more likely you will survive. Of course you must "fly" the aircraft to the "landing" and utilise as much of the stall as possible. preferably stalling at the point of impact.

[APenNameAndThatA]

I'm often surprised at the lack of interior finish and poor design in many RA aircraft - interiors that could be easily upgraded to offer a much higher level of body protection when you hit it in a crash, if more padding was added and angular shapes rounded.

If you take a look at the HK Holdens, they were the first Holdens to offer a real "driver and passenger safety" design. Simple things such as better dash padding, elimination of sharp edges in interior fittings, a blunt gearstick knob, breakaway interior mirror, and so on.

Many injuries from crashes are the result of the body coming into heavy impact contact with dangerous sharp edges and unforgiving attachments and controls. It's surprising the number of people who were impaled on sharp-pointed gearsticks in prangs in earlier days. Solid steering shafts that were driven through the steering wheel to impale the driver, led to the now-standard collapsible steering column that we take for granted today.

 

I'm sure that with a little more thought, many RA aircraft designs could be easily upgraded with safety padding (including instrument panel padding) that would lead to better survivability for RA pilots and pax involved in forced landings.

I see many instrument panel edges on current RA designs that look like they belong to 1920's models, as regards sharp edges and a lack of padding.

Of course, if your impact speed is high and the angle of arrival is steep, then no amount of safety features will save you.

 

Good points. With LSA's, I never thought past the steel bars that are at head height. They are not present in cars, which are are monocoque, and when there is a chassis, it is below one's feet. Internal roll cages are illegal, as far as I know. I wear a helmet. Fixed wing pilots not wearing helmets seems to me to be just a cultural thing. Helicopter and aerobatic pilots wear them. And if your aerobatic routine goes wrong, a helmet is the last this that will save you!

[APenNameAndThatA]

That's another whole area with some terrible secrets; people with agendas; funding scams etc, so don't get too upset.

I became intrigued at the stream of criticism on the Ford site over the poor star rating of the Mustang. You would have thought it was an accident waiting to happen when you read the comments, so I went looking for the test standard. Fontal collision tests are based on a head on crash against a car of similar weight.

 

The testers demoted the Mustang when it hit another Mustang, but these days it's one of the bigger cars coming into Australia. A Mini car is also tested against its equivalent size.

I quickly realised I'd prefer a 3 star Mustang to a 5 star from the mini category.

 

This issue is where the lies and politically correct spin impact on "objective" testing. If the frontal testing was done against a car/object with a standard mass, then the big cars would get better ratings and small cars would get worse ratings. As far as I know, people don't only have head ons with cars of the same weight. Lies. That this is not something declared, it amounts to lies.

[turboplanner]

Good points. With LSA's, I never thought past the steel bars that are at head height. They are not present in cars, which are are monocoque, and when there is a chassis, it is below one's feet. Internal roll cages are illegal, as far as I know. I wear a helmet. Fixed wing pilots not wearing helmets seems to me to be just a cultural thing. Helicopter and aerobatic pilots wear them. And if your aerobatic routine goes wrong, a helmet is the last this that will save you!

There is nothing wrong with wearing a helmet to a suitable specification for the application.

If you are considering making them mandatory for an application, that requires detailed test data and analysis.

[RFguy]

The low stall speed, and thus landing speed (or TO) buys a ton of survival headroom w.r.t crash energy .

 

I had a friend who was killed in a low speed vehicle crash, car slid sideways into a barrier and he hit his head on the door pillar... ("collision with door pillar").The car was fine and driveable, door could be opened, but that hard surface next to the head was his undoing...

Yes- fire suppression. In my younger car days, most had plumbed-in fire suppression bottles for the engine bay. If fuel gets shut off early enough, I guess not required if there has been no structural damage. I am not sure how many materials on aircraft are self extinguishing...... glen

[Old Koreelah]

Given the very low production numbers of factory-built planes, I doubt the authorities would bother to mandate higher safety standards, but there's nothing stopping home builders from doing so.

 

Self-extinguishing materials? Leather is good- widely used in aircraft seats because it lasts longer and is easier to maintain. Pretty soon fire-proofing might become less of a focus with the rise of electric aeroplanes- as long as they use the correct Lithiums...

[Kenlsa]

I seem to remember that the Mustang was only awarded 3 stars because the rear passengers were not properly catered for, remember this is actually a 2+2 vehicle so that star isn't relevant and it lost one star due to poor pedestrian protection. As an occupant/ driver of a vehicle I have decided to drive on the road, not the footpath. Problem solved.

Many of these ratings are not relevant. Imagine if we were penalised for public protection coz we hit a house. Yes... I have investigated vehicle accidents.

I was listening to an auto engineer on safety features only a few years ago, and when asked what he would want his daughter to drive, he said a HQ Holden or 4WD and use the other vehicle's crumple zone.....Nuff said.

Ken

[onetrack]

The Smart car crash test at 70mph into a concrete barrier proves up the vehicles crashworthiness, as regards body structural integrity, impact crumple zones, airbags, etc - but the bottom line is, if person had been in the vehicle, they'd still be dead. You can't beat bulkiness around you for protection.

[Old Koreelah]

...when asked what he would want his daughter to drive, he said a HQ Holden...

The HQ is the only car I know of with 'A' pillars narrower than your eyes- no blind spot to hide pedestrians, cyclists, etc. unlike too many modern cars whose'A' pillars are needlessly wide.

[RFguy]

The HQ is the only car I know of with 'A' pillars narrower than your eyes- no blind spot to hide pedestrians, cyclists, etc. unlike too many modern cars whose'A' pillars are needlessly wide.

Yeah, agreed. I have thought of putting some sort of display or projection on the A pillars so that I could 'see through' them. (IE from external video imaging) .

[Old Koreelah]

Yeah, agreed. I have thought of putting some sort of display or projection on the A pillars so that I could 'see through' them. (IE from external video imaging) .

The same technology that DARPA is using in its invisibility program?

[skippydiesel]

The low stall speed, and thus landing speed (or TO) buys a ton of survival headroom w.r.t crash energy .

 

I had a friend who was killed in a low speed vehicle crash, car slid sideways into a barrier and he hit his head on the door pillar... ("collision with door pillar").The car was fine and driveable, door could be opened, but that hard surface next to the head was his undoing...

Yes- fire suppression. In my younger car days, most had plumbed-in fire suppression bottles for the engine bay. If fuel gets shut off early enough, I guess not required if there has been no structural damage. I am not sure how many materials on aircraft are self extinguishing...... glen

 

 

Hi RFguy - You make point that few recognise - its the deceleration of the body & its internal organs that most often does the damage.

As far as I know there is no scientific evidence that speed kills but plenty to suggest that stopping (suddenly) does.

Your friends head was travelling at a certain speed, when the vehicle was brought sudden to a stop. His head continued at the vehicles original speed, until it contacted the now stationary pillar. His brain, in its protective casing, the scull, would have decelerated sharply rupturing blood vessels - curtains for your mate.

[spacesailor]

And the same applies to crash helmets.your brain is Not slowing enough to stop your death !.

But it does stop the mess ofgrey mater on the road.

spacesailor

[skippydiesel]

I am always amazed at the willingness of land bound vehicle operators, to travel in the lane closest to on coming traffic (when there is an option). A head on collision (phone distraction/fatigue/etc) of even 60 kph, will combine to 120 kph impact. The brain decelerated to this degree is most likely fatal, for most of the occupants of each vehicle.

[facthunter]

Sorry ..That's NOT factual. The change of speed in an equal weight same speed head on, is to zero same as if you hit that immovable object we keep hearing about.. IF it's a big truck you hit, your velocity change will be from X kms/hr forward to Y km'/hr backwards. ADDED together. "Y" depending on the mass and velocity of the truck above your mass and velocity. KE=s, M(Vsquared). Nev

[spacesailor]

You mean a 2.5 ton, 4X4, hitting a 700klgm, micro car, would be no different to hitting a concrete block, for each of them !.

I still llke the fact that the 4x4 has greater distance between the drivers head and the next immovable object, compared to the smaller car,s on the road

spacesailor

[turboplanner]

You mean a 2.5 ton, 4X4, hitting a 700klgm, micro car, would be no different to hitting a concrete block, for each of them !.

I still llke the fact that the 4x4 has greater distance between the drivers head and the next immovable object, compared to the smaller car,s on the road

spacesailor

Some time around the 1970s or 80s we reached a point where deaths from head injuries in cars were lower than 4WDs, and they were given progressive crumple rate which stooped that. Heavy trucks also got progressive crumple rate, and even though we still put bull bars on them we mount the bull bars on the safety items so the whole bar comes back.

[facthunter]

IF you were referring to ME spacey NO I didn't say THAT at all. I said the opposite. Hit a faster and or heavier vehicle head on and you are worse off than hitting a brick wall.. Crumple zones and extra good design mitigate that to some extent in that the (kinetic) energy is dissipated over a longer time reducing the deceleration force applied to the occupants. Nev

[skippydiesel]

So Nev - Leaving aside differences in mass, speed, gradient, road conditions, etc; If I hit a brick wall at 60 kph (most of my concerns are about vehicles travelling at 100 kph) I will most likely survive - yes? BUT if I hit another vehicle also dong 60 kph, head on, the combined force (energy) is not the equivalent of hitting the brick wall at 120 kph (which is likely to kill me) ??

[pmccarthy]

So Nev - Leaving aside differences in mass, speed, gradient, road conditions, etc; If I hit a brick wall at 60 kph (most of my concerns are about vehicles travelling at 100 kph) I will most likely survive - yes? BUT if I hit another vehicle also dong 60 kph, head on, the combined force (energy) is not the equivalent of hitting the brick wall at 120 kph (which is likely to kill me) ??

No. Each vehicle absorbs its share of the energy, so it is like hitting a brick wall at 60.

[RFguy]

relativistic interactions will be different .

[turboplanner]

 

Recreational Aviation aircraft have an upper limit where it is pointless discussing energy because it isn't feasible in 2020 to design a frame to absorb the forces of a stall/spural dive/collision with terrain due cloud etc. so we focus on Operations for that.

 

This allows us to focus on things the frame can change, like the slap down in a nose over.

 

The bubble canopy when made out of materials light enough to produce a working RA aircaft, is probably not a good design to proceed with.

One alternative for a low wing is to bring the fuselage up to canopy height from the tail.

Another is to focus on a structure strong enough to allow egress of people from the side when the aircraft is upside down, and also prevent a locatise object like a rock or log from killing them in the slap down.

[Old Koreelah]

Glen is spot on. From attending well over 100 serious road crashes I can tell you that almost no head-on collision is square-on.

 

The vehicles tend to be violently spun around, ending up metres from impact and facing the opposite direction. The field of debris strewn down the road and off onto the roadside gives some hint of the side forces on peoples’ bodies and heads. (Hence the importance of side airbags).

 

Even apparently deliberate head-ons resulted in massive side forces on the occupants.

 

(I can also attest to the amazing protection given to a driver’s face by an airbag, even in a 160k impact.)

[RFguy]

I like to assume for survival , that the we're not talking about the pilot breaking the plane for any other reason than a takeoff or landing mismap (both are slow) . Pilots slipping their aircraft sideways out of the sky on excessively steep base turns , not much to do about that. Unless you land like one of the mars probes- inside bouncing airbags.

 

I would have thought the canopy made of heavy Polycarbonate (Lexan) , shaped in a parabola, and havign the ends well anchored, would have been pretty damn strong. I know POlyCarb goes a bit milky in the sun for long periods, but.