Crashed plane repaired

Michael · July 14, 2019, 10:57:01 AM

Last weekend I crashed my new Hangar 9 20CC Mustang. It was not a total loss, but it was more than a scratch and dent.

The first step is to pick up all broken pieces, even the tiny little parts. If I'm going to repair something, I tend to treat it as a puzzle, and put the parts back together as best as I can.

The second step is to analyze the crash. Was the crash a fault of the design of the plane, or was it pilot error. Understanding the cause of the crash can suggest changes to the model if the flaw was in the design, or it can suggest a better way of flying to avoid the same kind of crash a second time, if it was pilot error.

Third step is to examine the model and broken/damaged pieces to see what needs to be repaired, how it needs to be repaired, and what might need to be replaced.

Fourth step is to do the work.

Michael · July 14, 2019, 10:58:19 AM

I picked up everything but the smallest splinters. Step one accomplished.

I thought about the crash a lot. My flight was excellent, and the plane was flying nice and straight. The crash was on landing.

I was landing towards the north with a fairly strong east crosswind. As I was descending for a landing, I applied full flaps and the plane slowed down considerably. As the plane came towards the runway, it drifted closer (west) to the pilot stations. The plane began to stall. The plane torque to the left. I applied full right ailerons and full throttle. The plane cart-wheeled on the ground damaging the cowl, motor mount, wings, rudder, and tail wheel.

After careful consideration, I realized the fault of the crash was pilot error; me!

I was trying to do a smooth and slow landing on the runway. With the strong cross wind, I never should have used the flaps (or certainly not full flaps), and should have tried to land on the grass, which would have slowed a faster landing. The wheels on this plane are 4" in diameter, and this would have easily rolled on the grass. Using the flaps caused the plane to slow, drift to the pilot stations, stall and crash.

Next time, no flaps with a crosswind.

Michael · July 14, 2019, 10:59:02 AM

I took the plane and the broken pieces home to examine.

The cowl was damaged. The motor mount was shattered into many pieces. There were small cracks in the wood structure in the mid and forward fuselage. One wing flap was broken loose from its control horn. The aluminum wing joiner was bent. The rudder was ripped off its hinges. The tail wheel wire was bent out of shape. The rudder servo gears were stripped.

In my opinion, everything could be repaired, and the servo and aluminum wing joiner could be replaced. A new cowl could be ordered, but it was expensive, and I felt I could do a reasonably good repair.

Michael · July 14, 2019, 11:01:14 AM

The most serious damage was to the motor mount. Since I picked up almost all damaged pieces, the repair would simply be to carefully glue together the pieces, and to re-enforce the damaged parts with plywood. I did this slowly with success. When fully repaired, I screwed the motor back onto the model, and the motor back onto the motor mount.

Michael · July 14, 2019, 11:01:55 AM

I bought and exact diameter aluminum tube at Home Depot, but the material thickness was too thin. I bought a snug fitting wood dowel to fit in the tubing to make up for any strength that might be lacking. This was also a simple repair.

Michael · July 14, 2019, 11:02:47 AM

I carefully applied appropriate glues to slightly damaged areas.

Michael · July 14, 2019, 11:03:23 AM

I glued the rudder back on its hinges; bent the tail wheel wire straight, and replaced the stripped servo (under $20).

Michael · July 14, 2019, 11:08:35 AM

I repaired the cracks in the cowl by taping the gaps tightly, applying fiberglass cloth on the damaged areas on the inside of the cowl, and soaking the cloth with CA glue. Small broken pieces of the cowl were glued in place, and re-enforced in side with more glue. A bit of paint was used to touch things up.

Michael · July 14, 2019, 11:09:02 AM

Wing repairs were very minor.

Michael · July 14, 2019, 11:09:25 AM

The plane is repaired and ready to go.

sihinch · July 14, 2019, 11:52:09 AM

Looks amazing! Well done Michael. You are a Master.

davidk · July 14, 2019, 01:03:16 PM

Is it possible... it looks better than before... or at the very least that it's not met any ground with anything more than cordiality?

bweaver · July 14, 2019, 03:46:33 PM

A great job and a great reminder to pick up all the pieces. That's why I always carry a recovery bag with me.

A little patience, a little of the right glue and use of different reinforcing elements can bring a plane back to its former self.

While not all crashed planes can be reconstructed, many can. This is proof. Excellent post!