Template for the .15 Engine Pylon on my 3-Meter B.O.T.

dinsdale wrote:I see that you've made no concessions at all to aerodynamics. Do you experience any noticeable drawbacks, or don't you think it matters a great deal in that situation?

Yeah, in setting it up, I was going entirely utilitarian with the main emphasis on hauling cameras. I HAVE launched it with my Hi-Start as a pure sailplane, and really couldn't really tell any difference, but I'm also just a Sport Flyer, so someone with a competition/performance background might notice it.

I decided to try putting the tank up front, opposite the engine, just to help the CG a bit, and the open, smooth surface behind the engine might let a little more cooling air swirl around it along with making it easier to clean. It would be a simple job to build a fairing and streamline the pylon to clean things up, but it's extremely handy having everything out in the open for maintenance.

With the type of Boomers (thermals) that cut loose out here on a good day, I've many times flown both B.O.T.'s for extended periods of time (over half-an-hour...a long time for me to stare at the sky) with the engine pods' drag having no effect.

dinsdale wrote:I see that you've made no concessions at all to aerodynamics. Do you experience any noticeable drawbacks, or don't you think it matters a great deal in that situation?

I doubt it makes much of a difference. Kim has logged billions of hours of flight time. My guess is if it didn't work well he wouldn't have shared the info.

John Goddard wrote:Don't tease us Kim where's the video?

Hey John,
I didn't think to make a video of the build, but will be glad to try to answer any questions with photos of the pylon. It's pretty simple, and actually not finished yet as I intend to add an additional anchoring bolt in the center front of the pylon deck.

I've been using rubber bands to hold it's nose down to the wing, but plan on boring a hole through the wing, and installing a drilled dowel through it's center to guide a nylon wing bolt to engage the pylon base.

cribbs74 wrote:

dinsdale wrote:I see that you've made no concessions at all to aerodynamics. Do you experience any noticeable drawbacks, or don't you think it matters a great deal in that situation?

I doubt it makes much of a difference. Kim has logged billions of hours of flight time. My guess is if it didn't work well he wouldn't have shared the info.

Yeah, my first attempt at building a pod for the 3-Meter B.O.T. was a monstrous affair! It took a little while for me to adjust my vision away from the power needed for regular sport planes down to that needed by a slick sailing machine.

I may post photos of it...titled "Redneck Engineering". It used an O.S. .25 and was a pretty stout piece of work! It may still get chopped-on a bit and installed on an airboat of some kind.