Kestrel

Wingspan:(top) 48 inches, length 26 inches

Power: speed 300 with 8 cell 720 mah nimh aaa

Gears: steel and delrin gears with ball bearings

Flapping frequency: approx 6 cycles per second at full throttle

As you can see from the photo below the large gear is connected directly to the wing flapping mechanism. There are two much smaller gears on the other side of the fus, (one on the end of the motor) that enables the motor to run very fast, while the wings are limited to about six flaps per second.

You can see the plan shape from this next picture. The wing area is quite large when you consider just how fast it has to move to propel the machine forwards. Running the Kestrel in a test rig (small vice), I was amazed at how much air the wings moved backwards when flapping at less than half speed.

The first flights were at one of the Aldershot Model Club indoor meetings, where there was enough space to fly small electric r/c models in the playing field outside. It was one of those lovely May evenings when the wind had died down and the temperature and humidity were high. Graham was on hand to hand launch, and the Kestrel flapped off with no problem at all. All that was required was a little down trim. I was suprised how easy it was to fly, and now responsive it was. Gentle circuits, slow and low passes, attempts at gliding (you have to stop the wings at the correct moment), followed by slow approaches to land, were the order of the evening. All this and suprisingly good endurance.

Launching is not difficult, but when the wings start to flap, the body of the Kestrel vibrates more than a conventional plane, and fingers must be kept away from the gears. Apart from these things the kestrel just needs a positive nose-high push forward to launch. No javalin launches are required.

Amazing amount of flex (thanks for the flying shots George)

One memorable moment during the second flight was provided by one of my club members. A Heron flew past, having taken off from the local lake, and a voice piped up saying, "Hey look colin, you've pullled!?" Don't you just love your flying pals?

If you are interested I bought it from R&R Model Aircraft in New York. Their website is worth a look, for the Kestrel and for their slope-soaring pterodactyls!

Thanks Graham, without your initial persuasion I would probably be still looking at the video clips on the R&R website.

And finally, as the saying goes, my friend Dave shot these two videos one evening just before dusk. The result is rather moody (another word for dark), but interesting none-the-less. Dave described the first as, "rather manic", as you will see.