The Saftey of bubble canopies

[Guest disperse]

Bubble canopies look great, provide a good range of vission. But if you land upside down, It would seem your in a whole lot of trouble.

 

What are the ways to over come this problem. ie: emergancy release etc.

 

too many planes are not designed to crash ??

 

 

[shafs64]

just landing upside down would be a problem i think !!!!

 

Paul

 

 

[Guest Macnoz]

Random thoughts on bubble trubble

 

• Better visibility
   
   
  
• Higher exposure of occupants to UV -- what the betting that most of those canopies or materials are made at the other side of the antipodes where the same consideration may not be given to sun protection
   
   
  
• If you, and the craft survive an inversion during the landing the chances are the difference of egress between canopy and door fitted craft will be negligible
   
   
  
• A poorly fitted or incorrectly closed rearward hinged canopy could cause damage to tail section or pusher engine / prop on separation
   
   
  
• A poorly fitted or incorrectly closed forward hinged canopy should be inclined to stay with the craft in normal operations unless the hinge gives way
   
   
  
• A sliding canopy partially opening for whatever reason would begin to behave as a rearward hinged canopy
   
   
  
• Considering the fuselage alone surely some lift is created by any protruding curved canopy resulting in forces acting on the hinges and latches that exceed those acting on doors.
   
  

 

 

 

[Guest aircraft1]

What happens when a high wing lands upside down, do you think the doors will open when the airframe is twisted ? What about landing on water, will a low wing float so you can sit on the top of the plane or will the high wing have the doors underwater ?. It all comes back to the perennial battle, which is better, holden or ford, high wing or low wing. In my opinion!

 

(moderated for tone - Ian)

 

 

[Kaz]

Having had 2 planes with bubble canopies I can tell you have I spent a lot of time thinking about this exact topic. I have an emergency evacuation procedure for all scenarios... I have to think about something while Matt flies!i_dunno

 

Our solution in the first plane was to carry an emergency knife with us whenever we flew to be able to cut our way out of the canopy if we ever landed inverted or if the latch couldn't be opened. My hope for a water landing was always landing right way up and the low wings giving us that bit of extra time to get out.

 

The CT4 comes with it's own emergency knives and a jetterson canopy so I don't have to think about getting stuck inside so much. I just work through the procedure for what I would do in the event of a bad landing. Matt will be busy so I'm radio and canopy girl. My biggest worry with the CT4 is it weights a ton and will nose down very quickly in the water so I have ensured I can get my 5 point safety harness off quickly (making sure I can gets Matt's undone too if required) and to not get smacked in the head with the tail as we nose over.:raise_eyebrow:

 

I am the ultimate in planning for the worse and find once I have the main plan set and a back up plan set, I don't think much about it anymore.

 

 

[Flyer]

I spend some time in a Texan (flysynthesis) and have wondered the same thing. (safety bit)

 

Firstly I think the aircraft needs a roll bar. Hopefully between the tail and the roll bar holding the plane up there will be some room to get out.

 

The next problem is opening the canopy. The texan lifts up and back so I dont think thats an option.

 

Do you carry a small hammer to break the canopy with ( I'm not fussed about the duco cause I've probably already scratched it ) or just open the canopy before landing thereby blowing it off ?? (the texan canopy will depart quickly in a slip stream!!)

 

With a high wing it is a bit easier, unlatch the doors before the crash and try to hold them ajar. This hopefully prevents them getting stuck in a twisted airframe....i_dunno

 

I do agree with Aircraft1 and that is dont crash.....however it is interesting and necessary to ponder what happens when it all goes pear shaped....

 

Regards

 

Phil

 

 

[hihosland]

just landing upside down would be a problem i think !!!!

Paul

the conveyor belt on sky hook scenario?

 

 

[Guest brentc]

In theory if you look at the aircraft from a side on view, you'll notice that the tail is high enough (or atleast should be) so that there is ample room for the occupants to not be squashed when up-side down in a low wing. Some aircraft do have rollbars at the rear of the canopy which is a good idea because if the rear fuselage snaps in the impact you would be quickly squashed.

 

Opening of the canopy is a real issue. I would highly recommend buying one of those safety smash hammer things to smash your canopy - buy 2 of them, one for pax too.

 

The Cirrus whilst not a bubble-canopy as such comes standard with a safety hammer which is a great idea.

 

A rollbar is a very good idea. A couple of years back a Corby Starlet had an engine failure in Victoria (it might have been GA registered from memory I can't recall) and it hit a hole and rolled over. When the tail hit the ground the main spar to the rear snapped and the pilot was fatally injured because the canopy offered no protection. The aircraft had very little damage and soon after appeared on the used aircraft scene complete with 'strapped' main spar. Rather distasteful but still unfortunately legal.

 

 

[slartibartfast]

Troy - the bubble canopy aircraft shown in your avatar has a roll bar, as does mine.

 

I figure the canopy would be easily broken or displaced when inverted.

 

 

[Mick]

Something else to consider with low wings and the possibility of a roll over is that the lower centre of gravity of the low wing makes it less likely to happen.

 

 

[Jabiru Phil]

Anybody know if a Jab will float if ditched?

 

Just wondering.

 

 

[Yenn]

Having a Corby Starlet I have given this some thought. A sharp pointed hammer could be of some help but there is very little room to swing it in that plane. My answer is to open the canopy if a crash is imminent and push the catches past their locking position to ensure they cannot engage. The canopy slides rearwards so on impact it is probably going to close again, but unless I am disabled I reckon I may have a chance of demolishing it.

 

Really it is just a case of luck, unless you can get rid of a canopy.

 

 

[blueshed]

I reckon if we all caried chain saws we could use them to cut our way out! or maybe even a cordless jig saw/circular saw, or even a hand saw, as long as you have a vent hole this would work!

 

Seriously has any one actually ever tried smashing a piece of perspex, it ain't easy. And if you have got a little carried away and used plexiglass you will have no hope!

 

If you fly a Jabby I reckon the doors would still open even if bent and twisted! Then again I am not wishing to find out!

 

Cheers Guy

 

 

[Guest aircraft1]

With most planes if you loose the canopy you will loose the tail !

 

If you open the canopy which doesnt hinge on the front you will probably loose control anyway, there was a Zepher whose canopy opened in flight about 18 months ago, apparently the Zepher CAN loop ! Fortunately he survived with just a broken leg (undercarriage)

 

 

[eastmeg2]

Or, get of of the laser watches from MI-6. As an added bonus you can zap back at anyone on the ground pointing a laser at you:laugh:. Just try not to burn a hole in your canopy while you're at it.:ah_oh:

 

 

[Guest brentc]

If you troll the web (possibly jabiru.flyer.co.uk) you'll find a picture of a small jab that ran out of fuel and ditched into the water. The pilot and passenger waited on top of it as it floated for rescue, then were towed to a marina where the jab was pulled out onto the boat ramp. Based on that I'd say yes, however it would depend on whether you had fuel or air in your tanks and if the tanks were ruptured in the crash.

 

Perhaps if in a jab you stuffed a yachting marker buoy down the rear it would be guaranteed to float?

 

 

[Mazda]

The aircraft I've owned have had canopies. I love them. The visibility is fantastic (which is a safety feature) and it makes you feel like you really are flying - up there in the sky, not enclosed in a box like a car. If you've read "Zen and the art of motorcycle maintenance" it says something about car drivers looking at the world as though through a TV, and bike riders being in the world. It's a bit like that.

 

Sliding canopies can open on the ground for instant air conditioning. Some can open in flight too (at least at certain speeds - mine is OK below 70 knots). I'm wary of hinged canopies because I've known of people losing them, either if they are left open on the ground in a decent wind, or if they have forgotten to latch them before take off.

 

My aircraft does have a roll cage and I've examined the wreckage of one that did crash and flip over. The canopy smashed on impact, the roll cage bent but held, and the occupants got out safely. They now have another aircraft of the same type and say that roll cage saved their lives. This type also has a centre stick so there is no control column or stick to worry about during impact.

 

Do you think a canopy and roll cage would be safer (or less safe) than a low wing cabin aircraft if they both flipped over?

 

I also know someone who flipped over in a real "bubble" type canopy aircraft, and he ducked before impact. He was OK and said he thought that ducking might have saved his life, so remember that one! His canopy smashed on impact too.

 

I wouldn't like to get a bird through the canopy though (as appears happened in that QLD accident) due to the loss of lift.

 

 

[Kaz]

Apparantly, the CT4 will fly almost as good without the canopy :raise_eyebrow:

 

I'm not going to be testing that theroy any time soon though...

 

 

[Mazda]

That's interesting Kaz! I'll have to remember that as it is a very similar airframe to mine. The Victa manual says it is OK to fly with the canopy open below 70 knots but I haven't tried it.

 

 

[BigPete]

I have seen two Jabirus inverted - on both occassions the doors were easy to open....

 

regards

 

 

[TechMan]

Anybody know if a Jab will float if ditched?Just wondering.

Ask Jabiru on that one. Rod Stiff was telling me at Natfly that South Africa is one of their primary testing grounds. A chap who owns a place on the edge of a cliff with an airstrip which runs out over the edge to the ocean was landing back from over the ocean and ran out of fuel. He knew he wouldn't make it, so turned and ditched. He sat on the aircraft for several hours before they came and towed him into the harbour. So yes, they do float.

 

Chris

 

 

[Matt]

Regarding the CT4, it was flight tested (by ARDU) without the canopy to test handling characteristics, affect on stall etc. Surprisingly as Kaz said the report concluded that the aircraft handled "normally" at descent speeds of 80-90 knots and only increased the stall speed by 4 knots.

 

It has an inflight release mechanism that will see it disappear over the tail (again something tested by ARDU...not in flight though but 2 actual operational releases endoresed the ground testing). The various emergency procedures which relate to ditching, forced landing etc. refer to jettisoning the canopy as one of the actions.

 

 

[Ben Longden]

I have seen two Jabirus inverted - on both occassions the doors were easy to open....regards

I agree. Damned impressive design work by Jabiru.

 

Ben

 

 

[Guest Rocko]

Having performed a high-wing "this way not up" landing in a Lightwing myself a few years ago, to my embarrassment, getting out was easy enough. Doors opened fine. It was the "completely drowning my sorrows" bit after that was more difficult ;>

 

Actually, I always had a question about bubble canopies made from Lexan. You can't hammer a way through polycarb, can you? Can only cut your way out. So, if they can shatter with a hammer, what are they usually made of? Perspex?

 

Scotty

 

 

[Bigglesworth]

Troy - the bubble canopy aircraft shown in your avatar has a roll bar, as does mine.I figure the canopy would be easily broken or displaced when inverted.

You do the Cheetah a diservice; Yes it has a roll bar (very strong one) but the polycarb canopy is tough as all hell it takes a lot to remove that.

 

It is a problem. I always wonder about a swamp landing which would flip the plane, then sink it.

 

I think you could remove the seat and rip the fabric and get out through the bottom; if you are as thin as me.

 

Something to plan for I think.