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Posted by dawsonh | Sep 01, 2011 @ 03:47 PM | 6,339 Views
This past summer a number of slope fanatics successfully recreated the famous "Mad" elevator setup popularized a decade ago by Benoit Paysant-Le Roux (AKA BPLR) one of the world’s greatest R/C pilots and progenitor of the Madslide 3D glider. (see video below).

BPLR Madslide 3Dglider (1 min 53 sec)

The most obvious element of a Mad elevator is the extreme throw: 75° to 90° each way... and you need all of that if you want to do flips. BPLR used full-flying stab with a pull-pull system, similar to what is used on powered 3D craft, to get the large elevator throws. Others, myself included, have experimented with push-pull setups, similar to what we see on indoor 3D planes. Both these systems work well; but have their problems as you reach 180° of total throw (you want to do flips upright and inverted... right?). Geometry starts to work against you at the extreme ends of the throw.

I recently started experimenting with pulleys to see if I could get the full 180° of rotation (or more )... without any binding or slack issues. The pulleys have an even pull at any rotation AND it doesn't matter that one pulley is larger than the other. This second point is important since most servos only rotate 90° to 120°.

I started out by computing the size of the pulleys. I wanted 180° or elevator rotation from my 120° of servo rotation. A little geometry helped be figure that the servo pulley radius had to be 1.5 times the size of the elevator pulley. (180°/120°=1.5)...Continue Reading
Posted by dawsonh | Feb 15, 2008 @ 05:59 PM | 9,144 Views
I am an avid slope soarer and especially enjoy flying acrobatic gliders. I recently got a nice video camera (Canon HV20) and since I mostly fly alone I had to devise a way to shoot and fly at the same time.

The solution I came up with was to build a helmet cam. I started with an old kayak helmet and carved a piece of EPP foam to work as a camera mount. I glued the EPP mount to the right side of my helmet. I use a small velcro strap to hold the camera securely to the helmet. I was hoping I would be able to track my plane "as is" but quickly realized that I need some sort of tracking aid.

I used some scrap plywood, coat hanger wire and tape to fashion a "sight." I bent the wire into an "L" so I had a nice horizontal reference line so I could match the horizon and keep the plane centered vertically in the frame. I put a small vertical wire so I could track the plane left and right.

I drilled a hole in the sight mount for a bolt (matching the tripod mount of my camera) to attach sight to the camera.

The attached pictures show how it looks.

I have taken several hours of video and have had some good success in recording my plane. I still find it quite distracting to fly and shoot. The video quality suffers as the flying gets more fun/difficult.

I mostly like to fly close-in so I use a wide angle setting. However I find that the camera will often lose focus as it tries to track to plane. The camera will also change the exposure as I fly over the ground and then into sky. To solve these problems.

I set my camera to:
Wide Angle
Focus at Infinity
Exposure to Manual

That seems to work well... just as long as I stay close to the camera.

I have posted some recent videos on my Vimeo site:
Le Fish at Mormon Lake Overlook, Flagstaff, AZ (2 min 32 sec)

There are also some at the RCGroups Sailplane Video Forum:

and Steve Lange's Slopeaerobatics site: