Fighter canopy design needs – what’s changed?

Reading about the poor Lockheed Martin F-22 Raptor pilot trapped in his cockpit for 5h when his canopy jammed, I couldn’t help wondering how aviation designers don't learn from history. Sixty-five years ago, the Hawker Hurricanes and Supermarine Spitfires had simple canopy designs enabling Battle of Britain pilots to roll them back just before engaging the enemy to ensure that they could get out in a hurry if necessary once the fighting started - something the Messerschmitt 109 guys probably couldn’t do because of the German fighter’s different canopy design.  Perhaps the design boffins at Lock-Mart need a history lesson on simplifying canopy opening mechanisms?

 

 

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posted on Tuesday, April 25, 2006 4:37 PM by Max Kingsley-Jones

# re: Fighter canopy design needs – what’s changed? @ Wednesday, April 26, 2006 3:09 AM

You are quite right - having the canopy open duriing combat ensures quick bailout when necessary. However, the underlying reason is that the canopy tended to jam and with the fuel tank being in front of the pilot, the chance of the pilot burning was great. Please read "Tale of a Guinea Pig" by Geoffrey Page, visit Wikipedia <http://en.wikipedia.org/wiki/Guinea_Pig_Club> or other sources and learn about the "Guinea Pig Club". Also see the movie "Battle of Britain". These are aircrew who pioneered plastic surgery for burn victims. Many of the earliest members were figther pilots during the "Battle of Britain" who flew Spits and Hurries.

I don't mean to belittle your comments, I just want to set the reasoning behind your statement to rights. As for the F22 - well, it's a new airplane and unforseen design problems (otherwise known as "***") happen. By cutting away the tranparency, the cause of the canopy jam was preserved for analysis and correction.

Regards,
Floyd
Aircraft Maintenance Engineer,
formerly of McDonnell Douglas & Lock-Mart

PS: I'm a Hurrie fan.

Floyd Masukawa

# re: Fighter canopy design needs – what’s changed? @ Tuesday, May 02, 2006 3:40 PM

Do you really thing opening the canopy at Mach 2 would be a good idea, or maybe the F22 pilot should slow right down just before getting into a fight to open his canopy, can you say canon fodder?

I'm not a plane nut, it just seems like a silly idea to me, perhaps I'm wrong and it isn't a problem to open the canopy.

Drew Whittle

# re: Fighter canopy design needs – what’s changed? @ Tuesday, May 02, 2006 6:08 PM

It seems to me that it is actually two different design problems: routinely opening a canopy and being able to get out in a combat emergency. If the pilot of the F-22 had *really* needed to get out, the canopy could have been jettisoned; the damage to the cockpit and airframe might have been greater with explosive bolts and rockets going off versus rescue chainsaw damage.

Thomas Terashima

# re: Fighter canopy design needs – what’s changed? @ Tuesday, May 02, 2006 6:41 PM

With a non retractable canopy, I guess the ejection system is going to be extremely hazardous. I would hope that this was a double failure and that along with the false indicator the manual activation system also failed.
What ever ssytem failure caused this problem, I would hope a detailed analysis of the fairure is done to ensure that the canopy can always be opened under any situation that the pilot deems necessary.

Guy Fraser

# re: Fighter canopy design needs – what’s changed? @ Tuesday, May 02, 2006 6:51 PM

I expect that ejecting opens it a different way, and that probably works just fine. Bugs will happen, hopefully this will be the last time it happens.

Ronald Pottol

# re: Fighter canopy design needs – what’s changed? @ Tuesday, May 02, 2006 7:25 PM

Correct, the Bf.109E had a side-hinged canopy that could not be slid back, but it could be jettisoned in an emergency. In this, the Messerschmitt designers were actually ahead of the Supermarine and Hawker teams. I was interested to see that the F-22 canopy does not have a ribbon charge built into the canopy to allow the pilot to eject through it without mincing himself in the process, something that is common on attack aircraft such as the Harrier. The charge is fired just prior to the ejector seat if the pilot cannot release the canopy....

Matt Bryant

# re: Fighter canopy design needs – what’s changed? @ Wednesday, May 03, 2006 6:23 AM

Yes, I have no doubt that opening the canopy of a pressurised cockpit at supersonic speeds is a wonderful idea, perhaps Max K-G would like to show us how its done?

David Julian

# re: Fighter canopy design needs – what’s changed? @ Wednesday, May 03, 2006 2:09 PM

"I would hope that this was a double failure and that along with the false indicator the manual activation system also failed."

No pilot wants to use ejection systems on a case like this. They are subjected to extreme G-forces which aren't advisable in any case but eminent death and in this case wasn't any emergency, just a malfunction.

"Do you really thing opening the canopy at Mach 2 would be a good idea(...)?"

I don't think he meant the canopy should be openable at Mach 2. What I read from is comment was something like "less is more". There is no reason that a canopy shouldn't have a way to be opened manually. In this case, the pilot is at velocity zero, altitude zero and still he couldn't get out of the plane. Something is wrong here...

Daniel Jana

# re: Fighter canopy design needs – what’s changed? @ Wednesday, May 03, 2006 2:15 PM

Looking at the Wikipedia page on ejection seats (http://en.wikipedia.org/wiki/Ejection_seat) the upper picture of the FA-22 seat test looks like the canopy is coming away in shards. Maybe this was an early design as shattering a modern canopy can't be easy. Having played with some high strength plastic 15 years ago (much thinner than the F-22's canopy) it tends to bend rather than shatter.
Further down the wiki page is a picture of a real ejection on an F-16. Here the whole canopy has been released.

The Hurricane had a problem with the canopy jamming (you can see in this article's picture that the runners are exposed). If the canopy framework became twisted or the runners damaged then the canopy would jam.

Climing out into a supersonic airflow is nearly impossible. Even at lower speeds, if you do manage then the chance of hitting the tail plane increases with speed. This is why the ejection seat was adopted.

I'd hazard a guess that recent maintenance may have caused or led to the F-22's canopy failure. Modern aircraft are so complex they must be a nightmare to work on.

sad61t