ASW 27 destroyed by lightning in trailer

On Thursday, September 26, 2019 at 8:31:11 PM UTC-7, Steve Leonard wrote:
On Thursday, September 26, 2019 at 8:27:06 PM UTC-5, 2G wrote:

The photo of the trailer showed a strike mark near the front of the trailer where the carpet ends. This indicated to me that it exited out of the bottom of the nose.

Tom

Hi Tom,
Looks to me like that picture is looking up into the fin box. I don't see any gray floor in that pic, but black like in the glass top of the trailer. There is red carpet visible in the elevator drive box, and burn marks on the white foam (owner added?) that might kinda line up with the top of the vertical being in there.

Just another opinion.
Steve Leonard

As a lightning guy who has inspected and analyzed many things struck by lightning (including aircraft, helicopters, gliders and vehicles), maybe I could add a few comments.

The lightning entry point was certainly the top of the trailer and into the metal control system for the elevator at the top of the fin. From the control system, it would have travelled to the bottom of the rudder and could either have exited straight down into the nearest metal of the trailer floor and/or forwards along the fuselage along the control rods and rudder cables. Exiting from metal, lightning typically leaves a nice characteristic melted area which would be easy to find if they were examined. How the lightning got out of the fuselage isn't obvious to me from the photos. If it went through fiberglass, the damage would be obvious.

Since the metal control systems of gliders are not electrically continuous, there is the possibility of arcing across gaps, which can develop significant pressure. The possibility of damage inside the the fin and fuselage from this cannot be known without inspection, but I would suspect it to be repairable. The wings are almost certainly unaffected.

Where the lightning exited the trailer to ground is also not known from the available photos. Many lightning-damaged vehicles I have examined have one or more flat tires, destroyed by lightning current. Tires are not very good insulators - they are black because they are full of carbon and may also have steel wire inserts. Flashover to ground from the axle or wheels is commonly seen in videos of vehicle lightning strikes. Just remember, lightning has traveled around 5 miles through air, which is a pretty darned good electrical insulator - a few inches from trailer to ground is nothing!

Mike