Saturday, August 11, 2012

More Cowbell!... er, I mean, GODFREY!

We went out to the field yesterday and managed to shoot some video of the Godfrey again. This time I decided to go about filming a little differently. I wanted to make the intro a little more exciting than a title screen, some funky music, and a takeoff... so I did some thinking and I think the result was pretty cool. The video is below, but first, I just want to say a few things about this amazing airframe...

With an 84" wingspan, this 27% Extra 300 was pretty much built to be powered by a DA-50, or similar 50cc gas engine. However, I really haven't had that much good luck with gas engines... maybe that's because we bought a first generation DLE-30 before they made some necessary tweaks to the design... but I digress... Anyway, we wanted to go electric. There aren't really a lot of good choices out there for a 50cc electric motor. You could go the knockoff route, but you may end up playing magnet pickup... or worse... You could also go a heavy underpowered route, which, let's face it, is so 10 years ago. Or you could go for a super light setup that gives you almost a 2:1 power to weight ratio. I, being me, chose the latter. For the motor, we turned to Hacker. I learned from the Sham-Wow guy that the Germans make good stuff... so we did some research and decided on the Q80-7M.

The Hacker Q80-7M can swing a 24x10TH Mejzlik Carbon Fiber propeller about 6400 RPMs and provide roughly 32 pounds of static thrust when measured with a fish scale. If you just found my blog by googling "RC Airplane" that means it swings a big prop, fast enough, to provide insane power. Also, with this setup, it pulls about 116 amps on the ground via an inline meter; and if you wanna go crazy, you can stick a 24x12 Xoar on it and pull about 130 amps and 37 pounds of thrust. Oh, did I mention this is all happening on 10S? Well yeah, 10S. It's a light and sweet setup, and it rarely comes down over 120 degrees F on a rather balmy Florida summer day with a heat index of somewhere around 105 F.

So, we had the motor figured out. Now it was time for the speed controller. Again, we have a few choices... well, two actually. One with a smoke system, and one without. So we turned to Castle for a Castle ICE2 160A HV ESC with wires about as thick as my pinkie finger, or one without a smoke system. Upon later testing, we discovered 160 Amps for an ESC on this setup may have been overkill... but hey, better than learning you pull 120 amps on a 60 amp ESC and wondering why your cowling's on fire. This ESC is a monster. It's big, chunky, and yet surprisingly light for its size. And since there's such a high amp buffer between 116 and 160, it comes down cool.

So all in all, we run 10S through a Castle 160A ICE2 HV ESC that turns the extremely awesome Hacker Q80-7M motor 6400RPMs that, in turn, swings a Mejzlik 24x10TH CF prop that blows 32 pounds of thrust over a 19 pound airplane, and let's just say... it's pretty sweet.

Not to mention it sounds Bad@$$!

--Tom K.

No comments:

Post a Comment