# My Safety Concerns About Bubble Canopies

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#### Pops

##### Well-Known Member
Log Member
Another reason to love flying a Cub with the door down . The Ercoupe had light weight plexiglass with a light alum at each end running in a channel. A hard hit with the elbow or your hand and the window will pop out of the channels.
I liked my gull wing doors on the F-12. Hinged at the center on top and if inverted just unlatch the doors and they would fall open at least half way. Nice heavy strongly braced windshield bow in front and a strong box bulkhead behind.

#### Wanttaja

##### Well-Known Member
I did the research to locate the site of a WWII P-40K off field landing where the pilot was trapped in the inverted cockpit for 3 days. He finally was able to break out enough plexiglass to wiggle himself out. The bottom hinged escape panel was held in place by the muck the plane had come to rest in. The plane was dragged out of the swamp and salvaged for parts.
A rollover structure should be a MUST...
Friend of mine was landing an open-cockpit Story Special (predecessor of the Fly Baby) on what he thought was a thin snowfall. Wasn't thin; the plane flipped upside down and trapped him inside. He ended up tunneling out through the snow. This picture was taken during recovery of the aircraft.

When they rebuilt the airplane (damage was actually fairly minor) they added a turnover structure. However, it was a thin blade with a small shelf on the top, probably wouldn't have helped in the snow. You can see it right behind the cockpit here, with an antenna installed on it.

Ron Wanttaja

#### 964SS

##### Well-Known Member
I affectionally refer to my Sonex in the summer with the canopy closed as an "EZ bake oven." it does get warm in a hurry until you get some air under the tires. After landing the best part of the flight is when you open the canopy to let the cooler outside air in.

The good part is that when it starts to get cold outside I can keep fairly warm in the little EZ bake oven ...
Yep. I say the same thing about my Pitts and Cassutt

#### 964SS

##### Well-Known Member
I have 3 bubble canopy aircraft. In the Pitts and Cassutt my plan is to jettison the canopies because those two are surely going to nose over in an off field landing.
the other is my sailplane and I have made many off airport landings in that with out any fear of nosing over.

#### 964SS

##### Well-Known Member
If it were technically and financially feasible, some sort of canopy jettison system might be worthwhile on some airplanes. Not all, but some.

Like several others here, I have quite a few off-airport landings in aircraft with big bubble canopies, and it never caused me a safety concern - because the landing speed was very slow and the landing gear was not prone to nose-over.

On the other hand, the one and only reason I have not bought a Cassutt as an inexpensive hotrod sportplane is that I can see an off-field nose-over and being trapped in it way to clearly. The Cassutt lands a lot faster than some other airplanes, plus getting out from under the mid wing spar carry-through, plus having to squeeze out with the weight of the whole airplane on you (under the wing)... seems like it would be rather difficult for someone who is not a 20 year old power-lifter. It really pi$$es me off because the Cassutt is the very best speed and control power for the buck, and it takes up a very small space in a hangar. Shouldn’t let that stop you from buying a Cassutt. It’s a fun hotrod. Just jettison the canopy before off airport landing. #### Riggerrob ##### Well-Known Member If it were technically and financially feasible, some sort of canopy jettison system might be worthwhile on some airplanes. Not all, but some. Like several others here, I have quite a few off-airport landings in aircraft with big bubble canopies, and it never caused me a safety concern - because the landing speed was very slow and the landing gear was not prone to nose-over. On the other hand, the one and only reason I have not bought a Cassutt as an inexpensive hotrod sportplane is that I can see an off-field nose-over and being trapped in it way to clearly. The Cassutt lands a lot faster than some other airplanes, plus getting out from under the mid wing spar carry-through, plus having to squeeze out with the weight of the whole airplane on you (under the wing)... seems like it would be rather difficult for someone who is not a 20 year old power-lifter. It really pi$$es me off because the Cassutt is the very best speed and control power for the buck, and it takes up a very small space in a hangar.
The simplest solution is quick-removeable hinge pins. Dozens of different light aerobatic airplanes can jettison canopies or doors by just pulling hinge pins.

#### Riggerrob

##### Well-Known Member
As you mentioned, Scott, in some aircraft the canopy is opened for takeoff and landing in case of a problem. Some sort of emergency egress tool is probably a good idea and maybe replacing the decorative frames with something like aluminum tape so it won’t prevent emergency exit.
US Navy (propeller powered) airplanes routinely took-off and landed with sliding canopies open to ease egress if they landed in water.

#### Riggerrob

##### Well-Known Member
Oh... and definitely 5 point harnesses as well.
Yes, a 5-point harness keeps you awake for the fire.
Sorry, old skydiving joke.

The fifth - crotch - strap holds the lap belt down against your pelvis.

#### Riggerrob

##### Well-Known Member
I'm guessing this was a joke. I would love to see someone try to even get to the bottom of a Zenith CH 650 when seated in it, much less get through a hatch. Very few small aircraft would allow such freedom of movement, especially upside down with a collapsed canopy limiting movement even further than it's limited to begin with. A bubble canopy would roast me alive long before I ever had to worry about flipping over on landing, so I guess I never have to worry about this.
Pretty much impossible to cut an escape hatch directly under the pilot's seat because it sits on the spar. You might be able to cut an escape hatch between the main spar and rudder pedals. Even this escape hatch location will need reinforcement around the edges and will add a few pounds to the empty weight. This is where a center-line (ala. Zenith) or side-stick (ala. Long-Eze) ease escape.

##### Well-Known Member
Bring an automatic centre punch. No swinging required.

#### cluttonfred

##### Well-Known Member
The key here is to consider emergency exit, whether inverted or upright with a canopy system that has jammed because of airframe damage in the crash. There are many ways to accomplish that—jettisonable canopy or doors, deliberately fragile transparency or frame, even an escape window inset in a large canopy or an escape hatch on the cockpit side or floor. For a fabric-covered tube or wood design the escape hatch is quite simple, just a clear space in the airframe (or a hinged or removable cross-member to make a clear space) and something like a fine steel cable threaded in the fabric (or a sharp knife).

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#### TFF

##### Well-Known Member
The clear space and the ability to wiggle. Both don’t necessarily exist in most airplanes. Fabric is easy. The need for fuselage structure is a lot harder problem. That you can twist like a teen, might be impossible.

I got my little project because it had flipped. Being an open cockpit biplane, he was able to get out, and he actually flipped it back over before anyone reached him. You are not going sideways without jaws of life. Side by side gives wiggle room. Something like a Bakeng Duece with a comfort door maybe, but they do give up fuselage strength for the privilege.

If it can’t be opened before or ejected, the spring center punch with a built in holster in the plane and one in the pocket for redundancy is probably the best bet. A bad landing, like mine had, has no time for decisions. Up and over. If you are in the air with most of these sporty planes, and you are seeing no options, you probably should have had the option of bailing out.

You can always be just plain lucky like the guy in Canada in the Christavia that had the top of the fuselage severed in flight by a plane in formation. The thing shuttlecocked it’s way to the ground. Not sure how he climbed out, if you being lucky, keep riding it.

#### Riggerrob

##### Well-Known Member
"... Something like a Bakeng Duece with a comfort door maybe, but they do give up fuselage strength for the privilege. ...."

Extra hatches rarely reduce fuselage strength. Instead, they add reinforcements around the hatch to return it to its original strength. All that reinforcement adds weight.

#### Riggerrob

##### Well-Known Member
The key here is to consider emergency exit, whether inverted or upright with a canopy system that has jammed because of airframe damage in the crash. There are many ways to accomplish that—jettisonable canopy or doors, deliberately fragile transparency or frame, even an escape window inset in a large canopy or an escape hatch on the cockpit side or floor. For a fabric-covered tube or wood design the escape hatch is quite simple, just a clear space in the airframe (or a hinged or removable cross-member to make a clear space) and something like a fine steel cable threaded in the fabric (or a sharp knife).
You might try sewing in zippers to form an escape hatch, but I would still holster a sharp, sturdy knife (USAF survival knife or USMC K-Bar knife) beside the fabric escape panel. Since one can often equal none, it is important to carry two or even three survival knives inside the cockpit. Perhaps sheath a survival knife beside each escape panel, plus an extra knife in you survival vest.

#### Martti Mattila

##### Member
This is a timely tread for me and it should be for everyone, I went inverted while forge landing with my Motorlerche and I was trapped and with gas leaking from tank venting tube. This time no fire, but helish time to wait a rescue on my knees. I had already made mock up side door to a extra fuselage that I have, so I am getting there but it is not easy, and deforming the structure in crash must take consider. Many times after crash canopy opening needs help from outside. There is hardly time for jettison when engine quits 200 f. on takeoff, and you do things that hopefully gets engine running again.

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#### BJC

##### Well-Known Member
There is hardly time for jettison when engine quits 200 f. on takeoff, and you do things that hopefully gets engine running again.
Glad that you got out OK. If I have engine failure at 200 feet, all I'm going to do is, without looking, push all three knobs forward (where I expect them to be already) as I maneuver to the most survivable crash site. If I get a chance, I'll verify that the booster pump is on. No messing with the ignition switch or starter. YMMV.

BTW, I have been trapped in a flooded cockpit, underwater, for an extended time. Ended up busting through the canopy head first. Yup, still have the scar, still itches.

BJC

#### ColonelRaymond

##### Member
I see pictures of low-wing taildraggers with forward hinging canopies and wonder if their owners have any imagination at all. I have, fortunately, never been offered a ride in one. I'm about to start building a Fisher 505 - high wing, open cockpit. I don't expect emergency egress would be easy but in the event of an inverted, fiery crash I would stand a chance of surviving. Being trapped inside a canopy in the same attitude doesn't bear thinking about.

#### 964SS

##### Well-Known Member
I think this is way over thinking.