Why Should I Rivet my Wings?

[March - April 1988]

Dear Carlos,

As you know, I've lost my interest in Moni's, but I know you'll pester me until you get your story, so you win. Your newsletter is a priceless vehicle to help keep people alive and well. I hope it succeeds. My Pucker story:

I'm probably the reason all you Moni builders were advised not to fly your machines before riveting the wing skins on. My Moni is now a pile of junk in the corner of the workshop and a piece of sheetmetal labled N87RB hanging on the wall. I'm lucky to be around. My first flight was in Dec 1983 and I had many of the 2 stroke adjustment problems, etc. on my first six flights. I'd done enough basic work on stalls and clearing the flight envelope. I'd had the engine quit, and realized the value of some sailplane flying in keeping these events out of the "Pucker" column.

On my seventh flight I was ready for some mild aerobatics. I entered a left barrel roll at 4000 ft. and, 3/4 complete, experienced airframe vibration, loss of elevator control and nose pitchdown. I closed the throttle and held full back elevator but the pitch attitude, airspeed and vibration level all continued to increase until I was at a nearly 90 degree nosedown attitude and the airframe sounded like I was inside a garbage can being assaulted by baseball bats. About this time there was a tremendous "crack" and the airplane dissapeared from around me. I was tumbling through the air losing conciousness, but still strapped in my seat. Because of the violent motion I was unable to release the lap belt. The last thing I remember before losing conciousness was reaching for my parachute D-ring while saying goodbye to the world.

Miraculously, I regained conciousness on the ground, where I slowly realized that I was still strapped to the rear of the airframe, which had joined me in a fully unconcious parachute descent to a sitting landing in a nice plowed field. Another complete story follows where I got the seat belt released, only to be parachute dragged in a 20 knot wind with one arm and a dislocated shoulder entangled in the shroud lines, before finally shedding the chute. There were lots of broken bones and aches and pains. The NTSB investigation revealed that the starboard wing skin had debonded. The skin had departed outward, broken the spar and broken the aircraft in half at the spar box.

After some healing, and doing some research, I found that experts had been advising Monnett against this bonding method. He subsequently mandated a riveted wing, but didn't describe why as eloquently as I could have. Your editor, Carlos Emmons, and I then stripped the bonded skin from his wings (he wasn't flying yet) so easily it couldn't be believed. A little loosening with a knife at the trailing edge to get a finger hold, and a single jerk had the whole skin in our hands! We had bonded both aircraft and followed the book.

There are several morals to the story. Here's some at the top of the list:

I envy you folks your airplanes. It is a terrific idea for low cost sport flying. Wish I had one.

Bob Brumwell

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