Sunday was nice and warm and I enjoyed prowling through my garage, looking for a plane to resurrect from the fleet of incomplete and damaged aircraft awaiting a bit of attention.

A small wing caught my eye: a 24-inch Wing Warrior Scrappy that I built last year. It came with a small brushed motor, a Johnson 250.

Last year I set everything up and tried to fly it, but I never got it balanced. So my flights were quite short and always ended in crashes.

Brushed Ignorance. And, I admit, I’m no fan of brushed motors. Most are made cheaply and they don’t stand up to hard use. Also, I don’t have much experience with brushed motors, which means I don’t understand them very well.

So I abandoned the Mini Speed Wing to pursue easier challenges.

But during my Sunday garage exploration, I was thinking about how much I love flying wings, and I have some extra brushless motors.

Hmmm…

I removed the brushed motor and its speed control and went rummaging in my box of spare brushless motors. I considered a very small Feigao motor, but wasn’t sure if I had a prop adapter that would fit it.

What about this nice black CD-ROM brushless outrunner from Lens RC? It would attach easily to the little motor platform on the Mini Speed Wing and it came with a prop saver which would fit a small propeller I already have.

Done.

Favorite Glue. I attached the motor to the wing motor platform with several pink cable ties and drizzled some hot glue (my new favorite adhesive) along the tube which holds the motor shaft. Then I fastened a little white Graupner propeller on the prop saver and hooked up a small brushless speed control.

Rummaging through my batteries, I found a two-cell Thunder Power 730Mah LiPo battery that fit snugly in the battery compartment. I installed the battery and tested the center of gravity with a line I’d marked on the plane last year.

Looked close.

Then I checked the power consumption at full throttle. About 4 amps. Great.

(This was wrong, I learned today, because I’d installed the propeller backwards. The prop is made as a pusher, so the markings are reversed from “normal” tractor propellers. Amp draw with the prop oriented correctly is close to 6 amps. Still OK, but not as miserly as I first thought.)

I brought the wing to Baylands this morning. (See a picture here.)

Wiseass Spectator. Mike Nadler showed up just as I was finishing programming the transmitter and moving the receiver connections around.

“You have obviously worked as a dentist,” Mike said, watching my sausage fingers wrestling with the tiny servo plugs.

I ignored him.

He followed me to the flight line to assist.

We launched the wing. It flew like a crazy bird, looping, upside down, out of control, then crashed.

Repeat 10 times. Each time, I changed the trim a bit and tried to understand what was happening.

I changed to a slightly heavier battery. It flew slightly less out of control.

We went back to the picnic tables.

Got Nickels? I fished in my pockets, looking for quarters. No quarters today, but I had three nickels.

Taped a nickel on the nose of the wing. Taped another. Then the third.

I returned to the Great Meadow and tossed the plane.

It flew perfectly. Flew for 10 minutes, circling, rolling, flying inverted, under perfect control. Beautiful.

When I put the battery on the charger, I found that it had used only 40% of the capacity, so 20-minute flights should be easy.

When I got home, I weighed the nickels: 5 grams apiece. So 15 grams (half an ounce) on the nose balanced the plane nicely.

This is a lesson I’ve learned before: tail heavy aircraft are impossible to control. Nose heavy is manageable. When you can fly the plane, you can dive to find out if it’s too nose heavy.

I replaced the nickels on the nose with half an ounce of lead.

Put the nickels back in my pocket, ready for the next plane.

Stats:

• Mini Speed Wing
• Wingspan: 24 inches
• Brushless 17-turn CD-ROM motor
• Graupner 4.9 x 4.3 prop
• Power at WOT: 7.4 volts @ 6 amps (44 watts)
• AUW: 6.5 oz., including 1.2-oz. 2S 730MAh or 3S 720MAh TP battery

Tags: Airplanes, Baylands, Flying, Radio Control, Wings.

This entry was posted on Monday, April 2nd, 2007 at 5:21 pm and is filed under Baylands. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.