What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

-25F, cracked canopy

WyoDave

WyoDave

Well Known Member
More than anything else, I use my RV6 to generate smiles.:D But my kids have all been alpine ski racers. So now that I'm no longer ground bound, I also use it to chase my son around to various races. Obviously that means flying in cold weather. So last friday morning I loaded up the 6, pulled it out of the hanger, and fired her up. All was well, started taxing out, then felt a cold breeze on my head. Checked the latch, the vents, all good...but still a breeze on my head. So I glanced up...WHAT THE HECK!? My canopy (slider) had cracked right across the top!:eek: Ambient temp was about -25F. I've flown in sub-zero quite a bit. But maybe going from a semi-warm (+10F) hanger to -25F was just too much all at once? Maybe I need to set a minimum temp limit for RVating? I don't know for sure. But, anyway, just a word of caution and wondering if anyone else has had this happen.
Have fun and fly safe!
 
David,

Bummer, I hate to hear that.

I had it happen to me at +5 but mine was only about 1.5" long.

Did you glue or screw your canopy in place? I'm thinking that gluing it might be the answer.
 
me too (sort of)

Hi David - Sorry to hear of your event. I cracked the wingtip on my Beech last weekend going from a semi-warm hangar (20F) to cold outside (-5F).

Do you know how the canopy was attached? (screws, rivets, glue). Did the crack start at a drilled hole?

Thanks for any info,
 
Arctic weather and cracked canopy.

Jon Johanson flew his world traveling RV-4 across the Arctic from Northern Canada to Scotland and suffered a crack in his canopy. This was during his third trip around. He is documented on Van's web site for the first two trips in 1995 and 1996, but the third trip in year 2000 is found on another web site, as is his flight over Antarctica.

Here is the link about his on Van's Aircraft web site:
http://www.vansaircraft.com/public/jj-persn.htm

Other links on Jon Johanson:

http://commons.wikimedia.org/wiki/File:Jon_Johanson_RV-4.jpg

http://www.southpolestation.com/news/rv4/rv4.html

http://www.taxi-strip.com/JonJohanson.html

http://www.bigdeadplace.com/johanson.html

http://www.nasa.gov/centers/kennedy/pdf/329135main_08.02.96.pdf

http://www.redorbit.com/news/general/19425/austrialian_pilot_offered_fuel_by_brit/index.html
 
What is the frequency of this occuring and what is the solution if it does? Being in Iowa, it does get cold once in a while, so I'm curious.. :)
 
Mine did the exact same thing this past Monday. Moved it outside from a 45 degree hangar to 16 degrees OAT. Right after engine start I heard a very loud pop. I now have a crack 4-5" of centerline right on top. :(
Yes, it was through a rivet hole.

Vic
 
I would hazard a guess that there are a couple things at work here. One is the potential thermal shock of moving from a warmish hangar to the cold outside. This in itself (I believe) is unlikely to cause a crack. I suspect that its a combination of the temporary stress set up due to temperature change in dissimilar materials (plexi vs. aluminum) coupled with the shaking that occurs during engine start. Of course, if there is a microcrack already at a rivet or screw hole, then that is where the crack will start. I would suggest that if you were to move the airplane outside and let it sit for a short time (long enough to allow the canopy and associated materials to reach near equilibrium with the air temperature but not long enough that the engine cools off too much) the problem would be minimized.

My two cents.

greg
 
Eeek!

:eek:
Wow, I had a flight a few weeks ago the plane went from 65 F to -15 F outside. I love to fly when it is cold, but you really have me wondering now.

Hans
 
What Greg said...

I had wondered if doing like Greg suggested, giving temps time to adjust, might have minimized the chance of this happening. I wasn't thinking so much in terms of vibration as much as the prop wash after start up causing it to cool at a much higher rate. When I can figure out how to replace it I'll at least attempt doing something different to hopefully avoid this happening again.
Thanks for the suggestions!
 
I had a similar thing happen a few years ago on my slider. Flew over DEN when it was probably close to zero F and a large crack propagated from the closing mechanism (like three others).
 
vic syracuse said:
Mine did the exact same thing this past Monday. Moved it outside from a 45 degree hangar to 16 degrees OAT. Right after engine start I heard a very loud pop. I now have a crack 4-5" of centerline right on top. :(
Yes, it was through a rivet hole.

Vic
Click to expand...
Vic,
I hope that wasn't in the new -10 ???
 
The thing that's really got me worried...

...is you guys saying those temperatures are 'semi-warm', more like semi-very cold!!!....says he basking in the down-under summer of 25ish degC - now that's semi warm! :D

Glad to hear nothing more serious occured than the canopy crack
 
I was thinking about the suggestion that the plane be pulled outside for a little bit before engine start to allow the canopy to reach ambient temperature first. Sounds like a great idea, but then what happens when you turn on the cabin heat as you're flying? Imagine the temperature differential across the plexi from a nice warm cabin to the extreme cold at altitude just a few millimeters away? What does this do to the canopy? With so many flying RV's out there that do this all the time, one wonders if there are other factors involved.
 
Same thing...

Same happend to me at the rear bow. But after investigation, the riviting aruond that Plexi was not the best. I suspect that sikafex bonding to a canopy attachment is the best way to go with minimum stress. The rivits may impose a greater stress when the hole is expanding in temperature extremes.

BSwayze said:
Imagine the temperature differential across the plexi from a nice warm cabin to the extreme cold at altitude just a few millimeters away? What does this do to the canopy?
Click to expand...
...With my heater?? can't even feel my toes yet! :eek:
 
Nope, wasn't the 10. I'm actually up to 32 hours on the 10, and hope to finish it this week end if the weather cooperates.

Vic
 
Bruce,

I would argue that IF I'm correct, that it's not the temperature difference alone, its the combination of the temperature differential plus the vibration associated with the engine starting. If the engine is running, vibration is (should be) much less than when it first turns over and fires.

Again, this is just my hypothesis - could be something entirely different.

greg
 
I live in North Iowa. I flew freight in Twin Beeches and C-402 etc for years. We flew no matter how cold it was and we tore up lots of equipment doing that. Broken door latches are trying to compress the rubber seals, congealed oil coolers that resulted shutting down engines from low oil pressure, frozen breathers that pushed out crankshaft seals, cabin heaters would quit and the gyros would squeal loud enough that you could hear them over a pair of -985s... Then they would fail with in a few days or weeks.

I have a personal policy that I do not depart if it is below 0F unless I have a really good reason and I don't depart below -10 for anything.

I know others live in colder climbs where this is normal, but those are just my rules....

Tailwinds,
Doug Rozendaal
 
You must log in or register to reply here.
Back
Top