M

mtclay

Active Member
I just purchased a flying RV-8A three weeks ago. I've been having a ball with it.

Yesterday while practicing touch and go's I experienced a bird strike just after liftoff around 250' AGL. It was an Osprey (quite a large member of the Hawk/Eagle family) who tried to share the cockpit with me.

It was amazing how fast it all happened. By the time I saw the bird it was too late for any avoidance manuvers. I'd estimate 1/2 second or less from sighting to impact.

He impacted the top of the front windscreen about 2" below the roll bar. The force and noise of the impact were incredible -- it literally shook the airplane. He/she hit so hard that many feathers were impaled in the plexiglass/fiberglass joint -- I was left flying around with a feather head dress sticking out of the top of my windscreen.

After landing and cleaning up the mess it looks like I'm left with two or three nasty scratches and one 3 and 1/2 inch crack (still closed, not open). All the damage is at the top of the windscreen to the right of center. The damage is not in the normal line of sight.

I realize that the damage could have been much worse, and I am very fortunate. Had the bird impacted in a different spot or at a different angle it could have shattered the canopy and caused bodily damage or worse.

What are my options for repair?

Do I need to replace the entire canopy system, or can the crack be fixed?

Thanks,
 
Mike,

Wow - that sounds nasty! Can you give us a picture - it'd be easier to assess the damage and repair potential.
 
It's comforting to know that the 8 will withstand something like that. Bird strikes are nasty!

Glad to hear you are ok.

Donald
RV-8 Empennage Underway
N-284DP Reserved
 
Bummer!

RV-8A 1
Osprey 0


Unfortunatly the only permanent fix for a crack I know of is a new windshield. The real question is can you only get the front half of the bubble? Also I'd check the AC43-13 it has a section on windscreen repair.
 
drill small (1/16) holes on each side of the crack, lace them together with safety wire, and put a bead of clear silicon over it. It will last a long time. Much cheaper than a full replacement, which you can schedule.

Good to know that a major bird strike like this is survivable!

Jim
 
Spare Windshield

Mike,
Sorry to hear about your midair with one of the feathered species but sounds like that big roll bar structure did double duty by backing up the too-thin plexi windscreen. When I built my 8 a couple of years ago I installed a 1/4" windscreen from Todd's Canopies in Ft. Lauderdale and I still have my original windshield cut and trimmed but never installed. Contact me at [email protected] or (817) 431-0374 if you are interested.
 
Plexiglass Crack Repair

I remember reading in the RV-List about a product called Weld-On 3 for plexiglass repair. http://www.rplastics.com/weldonguide.html

Here is a message from Scott Bilinski dated Aug. 8, 2005 about the subject.
"Weld-on-3 is Mythelenecloride (spelling) which actually melts the parts
back together. In your case it is best applied with a very fine tip needle.
Anywhere this stuff touches the plastic it will melt slightly. Since
Weld-on 3 is so thin it runs very easy, so maybe after bonding the piece
back in place you might want to get one of those scratch kits and buff out
any smudges. Everything you need is available at you local plastics shop."

I personally have not used it, but this product has been discussed several times in the past. Good luck with whatever repair you choose.
 
I'd use the 2-part IPS weld-on #40 (its used to make BIG fish tanks). I have some I used on acrylic/plexi-glass and it worked great. I have also used weld-on 16 and was not impressed. The only concern I would have is how well the Acrylic Scratch Removal Kits work to buff out the repaired area. If you try the repair I would like to hear your results and maybe see some pics..
I wouldn't be concerned with strength because weld-on (if mixed correctly) is supposed to be as strong or stronger than the canopy material.
 
Noel Drew, an RV builder from South Africa, described an interesting way to repair canopy cracks on the RV-List a few years ago. I have never tried this, so I have no idea how easy it is to do, or how well it works. It may, or may not, be useful for your problem. But, if it works, it should yield an acceptable repair, and if it doesn't work you are no worse off than now.

I would experiment with some plexi scrap first. You can probably get some from a local RV builder. I saved a bunch of my scrap, just in case I ever have to do this.

Kevin Horton

==================
Noel Drew posted:

I can share your feelings on a canopy crack. My RV6 windscreen decided to start a crack from the roll bar down some 6 inches that probably started from somebody else resting too hard on the edge. This is an early 1/4 inch windscreen that Van offered when the slider was first introduced and to the best of my knowledge is no longer obtainable.

I was considering my options when a glider pilot looked at it and said "weld" it like the glider owners do. I suppose there is always a first time for everything so I started seeking advice.

I first located some liquid methyl methacrylate monomer that is the raw material used in the manufacture of sheet plexiglas. It is not the glue that is sometimes supplied nor is it solvent. It is called stabilised monomer. Having stop drilled the crack, I cut a V shaped groove on the line of the crack leaving a narrow gap at the bottom and about 3/16" wide at the top. I located a thick needle for a hypodermic syringe and was able to lay the viscous liquid monomer in the gap with tip of the needle submerged to avoid bubbles. After somewhat of a learning curve I was able to generate a reasonable weld.

The problems you will encounter will be bubbles trapped in the liquid, a flow of liquid down the slope of the windscreen, the monomer going solid in the syringe, needle, and on the surface of the jar it is supplied in. I should mention that the monomer will evaporate and shrink in the groove if you do not get it to set quickly by exposing it to ultraviolet radiation. At different times I used the sun (very quick) and a crack testing lamp from the nearby engine shop. Less than a minute in Durban's sun will have it too stiff to go anywhere while it will remain liquid for hours in the ultraviolet free workshop. After a few false starts that were rectified by starting over with the Dremel, the result looked like a metal weld with a ridge of plexiglas on both sides. Careful shaving and sanding gave me a surface that polished up very well after it had set properly.

The end result is a line in my canopy that is smooth and transparent but it deflects the light as is does not entirely match the colour or refractive index of the original material. I am satisfied with the strength of the join and now regard the repair as an honourable scar on my companion and a satisfactory compromise to the huge task of replacing the windscreen.
 
To prevent the crack from getting longer and traveling to who knows where stop drill the crack now. Use a very small drill ( the smallest you can find #50 or smaller) and drill a hole just past where you see the end of the crack. This will stop the crack from going further and relieve the stresses at the end of it.

Norman
 
Prop arc first POC

I had a similar experience several years ago with a large seagull in California. To hit that area I don't see how you could have avoided the same experience I had - the first point of contact was in the prop arc. The heaviest piece of surviving mass hit the upper right part of the cowl deflected it in and bent down the sheet metal just aft of the cowl. Very small cracks showed up later in the paint on the cowl. Prop singles have this layer of protection of the human against bird strikes. I would try one of the recomended fixes but look forward to replacing the windshield.

Bob Axsom
 
Finally have a picture

Thanks to everyone who has replied.

From the research I've been able to do and all your comments it looks like the best course of action is total replacement.

I'll try to post a couple of pictures of the crack. You may be able to notice some feather shafts still imbedded in the fiberglass/canopy joint.


crack21uf.jpg


crack18td.jpg
 
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