First Flight

And here she is, officially know as AVI@TOR MK4  (Aerial Vehicle Intended @(Academic Testing) Or Research), taxing on the runway, ready for take off.

And she flew happy ever after, right? Well, let's call this one a learning experiment :P

First take off attempt:

So, what went wrong?

* Underspecified battery - not enough power for the motor to accelerate quickly and take off on a short stretch.

* Undercarriage designed for smooth surfaces - having one wheel in front and two in the back is good for maneuvering on the ground, but not so much when trying to accelerate on a grassy field.

Front wheel snagged on the grass, causing the plane to flip over. In the process breaking the steering wheel/rudder servo.

All of that was quickly resolved with a servo replacement and a beefier battery.

Or so it was thought, but the flip must have made some more damage, since on the next try the plane was vibrating a lot more, which was unnoticed until the video was revived.

First flight (but with shaky video from the first crash, the ending is still good though):

So, what went wrong this time?

Just as the plane was lining up to land, it started to loose altitude. Even with the engine set to full and elevator pushed to maximum. So last few meters off of the ground, the engine was cut off, which tilted the plane downwards, accumulating some speed and land hard short of the runway.

It felt as though the engine was loosing power again, which might mean the battery is still undersized. And the tilting downwards after the engine was cut off means the plane is nose heavy for this configuration.

But it also might be, that the (unseen) heavy vibration from the motor dislodged the battery, causing it to shift position, making the plane nose heavy and causing it to loose altitude.

All of that caused it to land hard, still almost horizontal, which would be perfect, but as with the first take off attempt, the front wheel got snagged. And with a much greater force this time, causing the front wheel to break off.

This would all be tragic if there was no data to make pretty graphs and pictures. But there is, so it's all good:

GPS data; realistic altitude estimation and position, speed & altitude from the autopilot.

Altitude and speed in graph form. It looks like the take off speed was around 40 Km/h.

Orientation data: yaw, pitch and roll. Black represents raw data and color represents data filtered with a Kalman filter. The vibrations from the engine make are too strong, so the readings are mostly noise.

What to do now? Well, we're wiser so we're going to improve it!

First redesign will be for the undercarriage. The two wheels on the back will be replaced with sturdier ones and be placed on the front. So the plane will be tail heavy is the weight of the plane is on the wheels. And the front wheel will be reused and placed on the tail, enabling it to steer the plane on the ground.

Also the engine mount, shaft and propeller (which will have to be replaced) will be expected to reduce vibrations, as will the mount for the phone/panoramic camera/autopilot module.

But before all that, some effort in to visualizing all the data with the panoramic video, since you can't post graphs on You Tube :P