I bought this Sportster Bipe on eBay. This post will chronicle my journey in getting it in the air. This is the first RC plane I have built in 20 something years. Things have changed… and changed for the better.
This airplane is rated for a .35 to .45 glow engine. There was also plans for a 4-stroke conversion to mount a 4-stroke engine. It was kinda fun to see the plans from the 1970s or 80s knowing what we know today.
I went with a Great Planes Rimfire 46 size electric brushless outrunner. I have a 60 amp Hitec ESC and will use a 6s 5000mah battery. I’ll probably start with a 10-7 prop, but will play with props until I get it just right. This plane should have PLENTY of power. The plans call for it to be 5 to 6 1/2 pounds. Mine came in at 5 lb. 14 oz with the 6s onboard, so I am loaded with power and well within suggested weight.
As for the CG, I built the plane the only way I could that allowed me to get a battery in and out without having to take off the bottom wing. The battery had to be all the way forward. I really just built the plane and laid out the inside the best way I could. I was shocked when I checked the CG and it balanced perfectly at the middle of the suggested CG range. This was GREAT news. No added weight. With this plane with a 6s 5000 battery, there is no room to move the battery backward or forward to achieve a CG.
I flew this thing on Monday. It shocked me that it lifted off in about 10 feet when I hit the throttle. I didn’t get to fly it much. The speed control heated up and the motor started varying speed without input on the second flight. The speed control was very hot and the cover had burned off of it. I’m going to swap out the Hitec 60 amp with a Castle Creations 100 amp. I thought the Hitec might not have the ability to handle this motor with a 6s battery. Lesson learned. While I’m fairly experienced on the airplanes, radios etc., I am still somewhat of a newbie on the electronics of it all. This has all changed so much.
During the flight time I did get with the plane, it flew well. I set up the throws as lined out in the instructions. Roll rate was good and it needed for elevator for my liking. It needed a lot of adjustments and I never really got it trimmed out before I had to park it. I’ll get it trimmed out the next time I fly it. It was very fast with the RimFire 46 and the 6s. It’ll be even faster with the more suitable ESC. I’m running an APC 10-5 on it. I’ve got a 11-5 I’m going to try next time as well.
I flew her with the new Castle Creations Edge 100 ESC today. No more throttle problems. Consistency in power all the way through the range and as much vertical as I could ever need.
I officially finished the covering job on this plane. I checkerboarded the bottom of the top wing and the bottom of the fuse and horizontal stab and I striped the top of the bottom wing. This machine is easy to see 🙂