RCM Sportster (oz6143)
About this Plan
RCM Sportster. Low wing sport RC model. Wingspan 49-3/4in, wing area 410 sq in, for .19 engines and 4 channel radio. RCM # pl-542.
Quote: "If you've mastered the RCM Basic Trainer, here's a .19 powered low wing sport aircraft that flies as good as it looks. K&B Superpoxy finish, Veco-Lee .19.
One nice sunny, smogless day in California we were out at the local flying site doing our thing with the RCM Basic Trainer (oz5103) when all of a sudden we said to no one in particular: If we took the same wing, rear rudder and elevator and put the wing on the bottom we would have a dandy, fun to fly model.
This is how it all began, so we proceeded to make these changes and now we have the RCM Sportster. The wing is the same as the RCM Basic Trainer except the aileron horns come through the top instead of the bottom. The rudder and elevator haven't any changes whatsoever. The motor mounts are the same but the fuselage sides are different. We also added a canopy and turtledeck.
Several months later we finally got the prototype assembled and ready to fly. Once again, we were back at our local flying site testing out our idea. We fueled up, flipped over the prop and we were ready to fly. All controls were checked so we proceeded to taxi out on the runway. Everything was working well so we gave her the gun and off it went.
I was amazed - it lifted its tail, and then broke ground just as gentle as you would want it to do. No elevator was needed, but a little rudder was applied. The only trim changes it needed was a couple of turns of down elevator. Other than that it was virtually trimmed out. We had a ball flying the Sportster that day and for quite a few more days since. We also tried some crosswind landings and take-offs with huge success. A little rudder has to be applied to compensate for the wind, but crosswind take-off and landing are possible with little effort.
Now we'll get into the construction of the model. We hope we have made the construction easy to follow and the model easy to build.
Start by building the fuselage sides - one left and one right. Draw a line on the inside of each fuselage side from the leading edge of the wing saddle to the top of the fuselage side at right angles to the top of the sides. This is the position of bulkhead No. 2. Cut the 3/32 x 4 x 13 in fuselage doublers in four equal pieces, cross grain (see parts list). Next, cut 2 pieces of the wing capstrips to 2-1/8 long, then cut the rear fuselage vertical bracing from 1/8 x 3/16 stock. Using epoxy, glue the 1/16 ply fuselage tank doubler to the sides; they go in front of the line drawn from the wing saddle to the top of the sides.."
Update 25/01/2016: Replaced this plan with a better copy scanned from a fullsize plan, thanks to Balsaworkbench, scanning by Don at EAC, cleanup by theshadow.
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by Joe Bridi
from RCMplans (ref:542)
IC R/C LowWing
all formers complete :)
got article :)
Found online 22/11/2014 at:
Format: • PDFbitmap
Credit*: Thermaler, Balsaworkbench, theshadow
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User commentsI flew this for over 15 years. 20 years later and I have the Great Planes electric version. It is even better.
GSFinlay - 29/12/2015
Here are a couple of photos of the RCM Sportster that I built from your plans, RCM 543, OuterzoneID: 6143 [pics 003, 008]. Converted to electric. It flies great with a Propdrive 3536-1400KV motor, APC 10x5E prop, 50 amp ESC, and a 2200 mah battery. Flies for about 8 minutes with throttle management. Needed 3 oz weight in the nose to balance (I moved the rudder and elevator servos to the rear of the plane). Weighs 3-1/4 pounds ready to fly. Thank you for hosting Outerzone!
RonaldSwenson - 10/10/2017
Hi guys. I built the RCM Sportster, plan OZ6143 from your great website! It is not completely finished. I still need to make something on the nose to cover the motor, but the maiden was a few days ago. The build was quite easy using the article but the plan actually explains itself. The motor is a D3530/14, 1100kv on 4s/2200mAh. Prop is 8x5 and this results in 1.250Kg thrust @~300Watt. I had to put some weight in the nose to reach proposed CC point. The flight went very well, no surprises. I gave full throttle in light wind and after 10, 15 feet she jumped in the sky gracefully, turns were smooth and she reacted nicely on the controls. I could fly her around at 40% throttle. The landing was amazing, just keep her nose in the wind and throttle back that's all. No tip stalls or snap rolls, she just puts her wheels on the grass. She flies very well, just a little left rudder correction as I stupidly built in too much side thrust. It's fixed now after some shimming under the motor mount. It is also a great looker on the field, lots of nice comments [more pics 004-007]. I made a waterslide off txt with "Outerzone RCM Sportster" on the wing. Thanks so much for letting us have these plans!
Ed_Vink - 17/04/2019
Hi guys, I wonder if you could add to the plan oz6143, some of the attached photos of my old RCM Sportster, built in 1973 and still flying [pics 009-012]. Thanks for your wonderful database. Best regards,
Sergio Piraino - 17/10/2020
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