Marc and I

June 11, 2008 by Steven W. Ells, Associate Editor

I hitched a ride to the Golden West EAA Fly In at Yuba City Airport last Saturday with Marc Cook, former AOPA Pilot senior editor, in his Glastar Sportsman 2+2 homebuilt airplane.

Marc is now the Editor in Chief of KitPlanes magazine. He built the majority of his Sportsman during a 3 week long accelerated builder assist program at the Glastar HQ at Arlington, Washington. We traveled against another 25 knot headwind–see my blog of last week–to find out the latest news about changes in the rule that mandate that the owner of a kit built airplane must complete at least 51 percent of the projects that make up that kit. As I understand it, the changes were pretty minor.

When we compared numbers I realized that my 50 year old Piper Comanche was either pretty advanced, or that the industry hasn’t made much progress. Marc’s airplane is equipped with a custom-built Lycoming IO-390 (200 hp). He cruises at around 142-145 knots TAS at 75% power leaned to peak (9.5 gph). My airplane is equipped with a carbureted Lycoming O-360 (180 hp) and I see cruise speeds of 132-135 kTAS when leaned rich of peak (10 gph) at 75 percent power. So I wasn’t drooling about the airframes or the performance, but I did a lot of drooling in regard to his avionics package. Marc was able to install dual Dynon EFIS systems, a Tru-Trak autopilot–with altitude pre-select and altitude hold–and one of Garmin’s slick little SL-30 nav comms to handle the pedestrian stuff. The Dynon units start at $2,400 while the Tru-Traks range start at $4K. Great avionics at a fraction of the price of certified units. Sure wish there were comparably-priced units for certified airplanes. Sighhhhhhh

One Response to “Marc and I”

  1. Marc Says:

    Thanks for tagging along, Steve. You’re better than Sirius…only missing the MUTE button.

    I’ll have to look at the data (logged by the Dynon D-120), but I think we were closer to 67-70% power at that mixture setting. The Sportsman will do 150 KTAS but at 12 gph, so I seldom fly it that way. On the airframe side, I suppose it’s a fair trade of one seat (mine has three, yours four) to leave the gear dangling and yet be slightly faster. There’s really no mystery why a lot of homebuilts seem fast: They have a lot of horsepower per seat, and also a lot of hp per pound of gross weight. Incidentally, the IO-390 is nominally rated for 210 hp.

    Finally, the TruTrak has vertical speed set but not in this configuration altitude preselect. I’ll be beta testing the new Dynon autopilot soon, which will have altitude preselect. You’re welcome to fly with me again to see how that works.


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