Emergency Egress
 

I noticed that several of you have purchased some type of emergency hammer to break the canopy for emergency exit use. I think this is a great idea no matter what type of canopy you have, so I bought one for my RV-7.

A week or so ago, I happened to be in the local maint. shop changing my oil and making a few adjustments on the 7. I was chewing the rag with the shop manager and he told me that they were going to break the windshield out of a Cirrus aircraft that was parked next to me in the shop as they were going to replace the windshield.

Seeing a chance to actually try out my emergency hammer, I asked and was allowed to use my hammer on the Cirrus windshield.

After smacking the *&^% out of the windshield for several minutes with the hammer, I got NOWHERE!

Now, I know that I am no "he man", but I consider myself at least average strength. The Cirrus windshield may be slightly thicker than the RV's and I don't know if they are made of the same material.

I know that they work well on tempered glass in autos, but this makes me seriously wonder if these emergency hammers are practical at all for RV's.

What do you guys think??:confused:

I think you should have pulled the chute and tried again.:D

Were you ever able to break the windshield?

I wasn't ever able to do anymore damage than to put quite a few little puchmarks on it. The shop guys used a die grinder and some less elegant methods to finally remove the windshield.

Don't know what kind of hammer you have, but if it is that little plastic thing with the pointed metal tip it is worthless on our canopies.

You need serious mass to smash the canopy. Many of use consider the passenger control stick to be our canopy breaker since you can use two hands to inflict a really hard stabbing impact on the canopy. Somebody sells a heavy steel point to install on the bottom end of the stick.

I make a special lightweight hammer to do this job which worked ok with a big swing in the shop but not very well if you simulated the typical swing you might be able to do upside down inside an RV. I rely now on my survival pack hatchet if I could get to it after the flip over- maybe.

You really need something clamped up front or in the pocket of you flight suit so it is within reach. A pistol has been mentioned but we're not allowed to carry those in Canada. I'm looking at a couple other devices which might work.

I can say, the standard auto crash hammers don't do the job too well even when sharpened to a razor point.

If the plane is on fire, the pistol seems like the quickest way to exit. You need to be out within 30 seconds or less. Maybe a big red crash axe like they carried in DC3s would be the ticket.:rolleyes:

Maybe this: http://www.ramset.com/721.asp

And builders are so paranoid about cracking plexi when drilling or cutting!

The hammer I have does have a plastic handle, but the business end has a fairly heavy chunk of metal on it. It is not as heavy as the older style crash axes I have seen in jet cockpits. I also tried standing outside the Cirrus and swinging as hard as I was able at the windshield, with the same results. I'm sure that a more massive hammer would help, but it would be nice to know if anyone has been able to use one of these heavier hammers to break out of a RV canopy.

just a guess, but it sounds like lexan[polycarbonate] to me. you could bang on that all day long with a 12# sledge hammer and not break it. it's a great choice for a windscreen especially with a duck heading at you at 150+ mph.

Car and Driver
 

When these hammers first came out

Car and Driver took one to a junk yard to give it a try.

Not only wouldn't it break a tempered glass window from the inside, they couldn't do it from standing on the outside.

Also, the seatbelt cutter didn't cut. The belt just bunched up.

They recommended against their purchase.

Lexan vs. Plexi
 

I have no personal expertise or knowledge on this subject, but just sharing something I read in an old RVator...

Van's canopies are plexi. They were questioned about using lexan instead, suposedly for it's higher durability and less tendancy to crack. Apparently they did some research, and found that (I think from Air Force tests) though lexan is indeed tougher, the increased flexibility posed other risks. In the case of bird strike, the theory (or practice... don't know if there were any actual cases) was that the lexan canopy could deform (cave in) from the impact, whack the pilot, and then pop back into shape. I can only imagine the NTSB report on that one...:eek:

Alternative.
 

And yet, these canopies seem to break so easily when building. Perhaps the best tool would ba a non-plexi drill and a portable battery powered drill. :)

Tracy.