First SPAD

We built our first spad aircraft and flew it this week-end.  My daughter christened it “Shadow Fleet 1” (she’s an Ender’s Game nut, like me, and got her inspiration from there)

It flew beautifully and I’m sold on using this building tecnique in the future.

We did some gliding trials to check the basic aerodynamic soundness of the design (it’s this rookie’s first scratch designed and built plane!) and after a few adjustments, it glided nicely.

First powered flight didn’t go that well – it pitched up a bit, and on giving down elevator, headed straight for the ground.  I managed to pull it out of the dive for a hard landing / semi crash, breaking the prop.  Prop wash over the tail made it much more elevator sensitive than what I experienced during the gliding tests (probably a noob mistake by me!).

I flew it again, using dual rates on the elevator, and a bit of down trim.  This time, it flew very well, but still a bit pitch sensitive.  I then adjusted the servo linkages so that the was less throw on the elevators.  The third flight was absolutely perfect (see first video below).  Very stable and flew in boring circles around the airfield for around 15 minutes on 1/2 throttle (I wanted check endurance and low power characteristics).  Ended up consuming 1100 mAh in 15 minutes.

For the fourth flight, I loaded it up with a bigger battery, and added two more batteries to the “cargo hold”.  This pushed up the all up weight from around 800 grams to around 1.4kg.  To my surprise, it easily handled the extra weight, still maintaining level flight easily at half throttle!  I tested some stalls and it stalls so undramatically, that I ended up hanging on full up elevator, no power, and it just floated down.  I tried accelerated stalls, slow stalls, all kinds of stalls and could never get it to drop a wing – except maybe for the stall turns.  That setup equals the weight of around 2 x 2200 mAh batteries, which should equate to around exactly 1 hour’s flight time (as I could still use the same power levels as the endurance test I did).  The body has space for 3 x 2200 mAh batteries which I may try with a more powerful motor.

The last flight was with the FPV gear.  Unfortunately, I added quite a bit of “up” elevator trim on the last heavily loaded flight and with the plane now much lighter, ended up with the GC a bit aft from where it was (still good, but more to the back).

This caused the plane to pitch up again during launch and resulting in a hard landing and prop breakage again.  Sadly I was out of spare props at this stage and called it a day.

Third Flight – plane now nicely balanced

Will add more close up pics of the plane later.

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About delabu

I am a software developer, coding mainly in Java and specializing in the GIS field.

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