Path to an Aerial Photography Drone - 3 - Blogs

Airframe #1 – Flight #1 – Who’s the U-boat Commander?

To make a long story short…Flew, crashed and ended up floating in the irrigation ditch.

After 2 weeks of 20 gusting to 50 winds I finally got a chance to fly… Winds were calm, a beautiful morning to fly.

The flight was airframe only, no payload.

I did a few “power assisted” glide tests to check trim and for surprises. The aircraft was a bit twitchy due to the enlarged control surfaces, I dialed in a bunch of expo to correct the problem.

The first part of the maiden flight held no surprises other than minor trim issues. ½ throttle provided more than enough power. The flight was going well, about 7minutes into the flight I got slightly bored…

Remember the wing strength concern? I did some medium power acrobatics, Loops and rolls and was having a bit of fun. I set up for a wide open throttle low pass and watched a rocket fly by. As I pulled into the climb out, I heard a popping sound as the wing buckled between the root and tail boom.

The next 30 seconds got quite “western” as I fought the flapping wing monster for a bit of control. I ended up bouncing off the bank of the irrigation ditch as a last resort to violating my hard boundary for the flight area. The aircraft ended up bouncing over the bank and ended up floating in the irrigation ditch.

Damage done:
Buckled wing due to high speed flight
Crushed nose due to ditch bank impact.
Broken wing tip due to recovery
Dead ESC due to water.

Things I learned:

It did fly and flew well when inside its airspeed envelope.

"Felt" very stable, makes for a good aerial photography platform

Very easy to build

Wing design has structural issues

Good payload bay volume

Did not do any payload capacity (weight) tests

The picture shows where the buckling occured.

Airframe #1 has been retired

Airframe #2 is on the drawing board

Design changes/additions for Airframe #2

Longer wing, 50 inches min.

KFM3 Wing

Better wing structure, 6mm x 6mm square carbon fiber tube as a full length spar

Strengthen or change materials for tail booms

Strengthen the tailboom / wing interface

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Comments

Russell B. Sutton April 18, 2011 at 10:04am

Awww.... We always end up learning more than we want to or intend on. Your not the only one man keep up the good work. Walmart has fiberglass hunting arrows witch make good spars and booms. Also blank fishing poles work well. Lowes sells this Baby blue 2x8ft x 2'' thick foamboard thats nice for building with. once you have your plane you can cover it with a layer of brown paper bags and watered down elmers glue. Once the glue dries hit with a little sand paper and a light coat of spraypaint. The added weight due to the paper glue and paint help and make it a lot more ridged. Next time I build another foamy I would like to vaccum bag it as well.
Matthew Tang April 18, 2011 at 10:01am

This has happened to me so many times. I always push the airplanes and overpower them. The last one was the RQ11 clone, I had a power 35 motor in it, I did such a sharp barrel roll with full throttle, the wing snapped off and the crash shattered the plane.

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