Low wing hinged canopy. Dangerous!

[ab3198]

My dad and I bought a Roko Via (low wing with forward hinged canopy) which is a great little plane- very well specced, good cruise, flys beautifully and looks great! The first comment my x-country instructor made was that it was a pretty dangerous place to be if you flipped it during a forced landing as you had no way to exit the aircraft. To be honest that wasn't something we thought about when buying the plane but is something we have thought a lot about since to the point we are considering selling and buying something else.

 

What are people's thoughts on this? Are you comfortable flying in a plane with this configuration?

 

 

[ab3198]

Sorry, dangerous was meant to have a ? not an !

 

 

[rhysmcc]

Would one of those emergency "axe" work to break the canopy and get out?

 

 

[bexrbetter]

Which canopies aren't "dangerous" upside down?

 

 

[Kyle Communications]

Any low wing aircraft is a trap if it flips over...doesnt matter which one...thats why mine is a high wing

 

 

[IBob]

In Butch Cassidy & The Sundance Kid, there is a great moment when thy have to jump into a ravine with a river at the bottom...and Sundance won't go, and Butch says why not and Sundance says I can't swim, and Butch says you damn fool, the fall will probably kill you.

 

I'm sure there's 1000 ways to die in every day of our lives. I just can't count flying a low wing aircraft in case it flips as being very high on the scale???

 

Sorry, that's not meant to sound harsh...and i guess an axe might allay some misgivings.

 

 

[crashley]

Any plane which is upside down is not a good place to be. Don't get caught up in the what if arguments. I carry a small axe located next to my seat which will make quick work of getting rid of the canopy

 

 

[Geoff13]

I will happily swap your evil dangerous low wing for my safe rock solid high wing if you like.

 

Straight swap no money to change hands. What say you??

 

 

[IBob]

I will happily swap your evil dangerous low wing for my safe rock solid high wing if you like.Straight swap no money to change hands. What say you??

I was thinking more along the lines of one of those downward firing ejector seats?

 

 

[cscotthendry]

Any low wing aircraft is a trap if it flips over...doesnt matter which one...thats why mine is a high wing

It's also partly why I fly high wing, that and not having a wing in the way of my flightseeing.

There have been a couple of cases that I know of where the occupants of a forced landing flipover have survived the landing and flipover, only to perish in the subsequent fire as they were trapped by the canopy.

 

 

[facthunter]

It is a consideration for sure. If you are upside down and petrol dripping everywhere, as it does in those circumstances, you won't be thrilled about it. One of the reasons I fly high wing. It's not difficult for a small plane to end up on it's roof. Nev

 

 

[bexrbetter]

Goodness what an optimistic lot some of you are.

 

 

[cscotthendry]

Goodness what an optimistic lot some of you are.

I wonder why RA Aus teach us about forced landings. Could it be that our aircraft do actually require us to do them sometimes? If you assume it's never going to happen, then when, not if, it does happen, you'll be totally unprepared.

Me, I assume that when I have to put my airplane in a paddock one day, it WILL end up on its roof. From thousands of feet up, those paddocks look nice and smooth. Driving alongside those paddocks on the way to the airfield disabuses me of that notion.

 

Hope for the best, prepare for the worst.

 

 

[facthunter]

It doesn't have to be a paddock All it takes is a gust of wind under your upwind wing, or a rabbit hole to collapse the nosewheel. You make your own luck. Bex . When I fly I like a fighting chance. Sports cars are required to have roll bars. Nev

 

 

[Oscar]

Several years ago, I looked at the RAA accident reports over a period of about a year and found that a very significant proportion of serious landing accidents ended in overturns. I can't vouch for the completeness of those reports, but from memory, my conclusions were that it was around a 50% chance of ending up 'dead ants'. By 'serious', I mean those that are in the 'accident' category for ATSB: major damage / injury. I would NOT put this up as an authoritative statistical summary, but as a general indication, I found it quite sobering.

 

In our class of aircraft, with MTOW limits that really stretch the requirement to make every last kg as effective as possible just for decent performance, the possibility of having 'redundant' strength for improved crashworthiness, is very limited. The most likely basic design to provide decent crashworthiness ALSO utilises the basic structure to provide a 'safety cage' concept: two results for the price of one, in weight terms.

 

A high-wing design must tie in the load forces coming from the engine, wings, liveware (occupants), fuel and other disposable weight and undercarriage. In a 'traditional' tractor-engine, high wing design, the c/g requirement means the occupants HAVE to be sitting in what is effectively a 'box' of reasonably (sufficiently) strong form to tie all of those load forces.

 

In a low-wing design, what you have is basically a beam comprising the mainspar and main legs, with a truss forward of that to hold the engine and nosegear, for a tricycle u/c design. The occupants are sitting (mostly) OUTSIDE the 'strength' structure: especially the upper torso, upper spine and head. Decent protection for what are your most vulnerable parts, has to be added to the structure - adding weight. At a minimum, you need for protection the equivalent of a 'roll bar' - as Nev says - that does not contribute to the basic strength of the aircraft, it is a parasite in terms of the aircraft empty weight. Plus: for a low-wing design, it is in practical terms impossible to have a 'closed box' structure; the cabin deformation that is a feature of the RV6 in a crash is a classic example of how this happens. (Later models of the RV6 style design have much better occupant safety).

 

Without beating the 'Jabiru' drum: Jab's very frequently end up inverted from landing accidents and they have an almost unmatched - I believe - occupant safety record. Part of that is a result of the form of construction, which is extremely damage-tolerant, but a lot also has to do with the fact that they provide a very, very good occupant safety cage.

 

Low-wing GA aircraft can be good for occupant safety by using their greater MTOW limits to allow the additional strength for occupant safety. I have no idea of the statistics, but I would suspect that - for example -there is not a lot to choose between say Piper low-wing and Cessna high wing light GA aircraft. However, I can't readily think of any Piper/Beechcraft/Mooney etc. GA aircraft that have hinged canopies..

 

 

[bexrbetter]

At a minimum, you need for protection the equivalent of a 'roll bar' - as Nev says - that does not contribute to the basic strength of the aircraft, it is a parasite in terms of the aircraft empty weight.

Oh oh, I think someone forgot to tell me that.

 

Plus: for a low-wing design, it is in practical terms impossible to have a 'closed box' structure;

Yep, I definitely missed the memos.

 

I'm starting to think you guys are ganging up on me and not letting me into the "Circle of Keepers" .... of "everything you can't do".

 

 

... apparently.

 

 

[ben87r]

GA aircraft that have hinged canopies..

There aren't any from the original manufactures either that I can think of but the DA40 and 42 both have tip up canopies, when I flew them it was discussed that if we ended up on its roof we would have to use the rear exit by climbing over the seats and going through the baggage door. Wouldn't have been easy nor fun.

 

Each design has its down falls, Cessna style doors may not open after if the fuselage has been crumpled, piper style doors (one side) don't offer many options (especially twins) if there is a fire near the door.

 

 

[facthunter]

Oscar's general description of the structures is appropriate. It's a by product of the wing configuration. You have all the high loads between the wing, firewall, U/C and seat support structure. A low wing with canopy is a box weakened by the cutout(s) for the occupants. It's not just the inverted situation to consider. It's a deforming force from the front as well that causes concern.. Nev

 

 

[Oscar]

Jeez, Bex - you sprung me!. You are NOT paranoid - I AM out to get you - obviously!. My comments re the basics of wing configuration potentially impacting on occupant safety could not POSSIBLY be general observations about the inherent structural differences between low-wing and high-wing aircraft, since yours is the only low-wing aircraft design. Ever.

 

FWIW: such is the path bestrewn with rakes in the grass for those with the genius to think outside the box (and yes, that was a deliberate pun). The fact that a fairly recent examination of crash statistics undertaken in the USA ( and I frankly cannot be ar$ed to chase it down right now) shows that the safest aircraft from a fatality POV were Jabs,. C150s and C172s - all of them, obviously by coincidence high-wing aircraft - is just another spurious fact designed to delude those who seek to find a safe option.

 

Bex - all those statistics, all the structural analysis etc. - it's all dodgy science probably being supported by the UN clique out to subject the aviation world to the rule of communists bent on subjecting us all to high-wing aircraft. And - to my shame - I've been seduced by all of that.

 

Fight on, mighty warrior! Save the world from expensive, over-hyped aircraft. And may your colour schemes be with you!.

 

 

[Yenn]

I also saw that US report about the safety of LSA aircraft. Obviouslty it has no bearing here as CASA deemed Jabiru to be too dangerous to fly without signing waivers. The most dangerous planes in the US report, don't rate a mention by CASA. Probably because they are not Australian designed and built. Jabs big problem was landing in tall poppy areas.

 

 

[Gnarly Gnu]

Bex will sort it for you with FiberFix.

 

 

[Raytol]

I have just repaired a Seawind amphibious aircraft that landed up side down in the water. It is impossible to smash a canopy from the inside and sitting in a seat! I suggest a battery powered angle grinder with a cutting disc. I have installed an escape hatch in two of these aircraft now.

 

 

[IBob]

I have just repaired a Seawind amphibious aircraft that landed up side down in the water. It is impossible to smash a canopy from the inside and sitting in a seat! I suggest a battery powered angle grinder with a cutting disc. I have installed an escape hatch in two of these aircraft now.

Excellent! I was wondering when we'd get to ditching, for we high winged fixed undercarriage submarines...)

 

 

[kgwilson]

If you end up upside down, you are likely to be completely disoriented & even if you have an axe or some other device that you could try to smash the canopy it will take some time before you work out where it is. In a low wing design having some sort of roll protection as part of the turtledeck bulkhead may stop the canopy from breaking but in a design with a complete bubble & no rear bulkhead it is likely that the canopy will be smashed & your head will be firmly planted in terra firma. As someone has said in a high wing design it is also likely that the wings would be deformed to not allow the doors to open so you are in the same situation.

 

I don't give a rats. I'm not that paranoid that I think about all those possibilities. My glass is always half full, never half empty. There is a risk in everything you do & if you are worried about what you are going to do if you end landing upside down, maybe its time to think of doing something else, tiddly winks seems fairly safe. Make sure you have a safe chair though and a fire extinguisher in case the house catches fire and you have 000 programmed into every device and......

 

 

[bexrbetter]

Oscar's general description of the structures is appropriate.

Only for how it's often done. Low wing cockpits are a structural issue, one that is successfully dealt with in various ways with sports cars.

 

Sadly the nonsensical quest for lightweight over common sense with small aircraft kills people, I refuse to subscribe to that for the sake of 3kgs.

 

since yours is the only low-wing aircraft design. Ever.

Nothing to do with it, you stated that is was "impossible" and that's what was responded to - and I not only refute the tag "impossible", I find it annoying, in an amusing way, when I'm halfway through actually physically doing it.