Prodigy (oz15905)

About this Plan

Prodigy. Radio control sailplane model. Wingspan 2m.

Direct submission to Outerzone.

Update 16/3/2025: Added review(s) from RCSD, Sept 1986, thanks to Pit.

Quote: "RCSD REVIEW. PRODIGY - A SUPER FLIER AND NATS WINNER. This month we are extremely lucky to have two reviews of this extremely interesting two-meter design by Paul Carlson. One is a review by Lee Murray from Wisconsin, and the other is by Steve Moss from Texas. It's just plain serendipitous to have received Lee's review about a week before the NATS (having no idea who would win) and Steve's review just before we go to press. It is interesting to see the comparisons so enjoy and judge for yourself.

OFF THE GROUND MODELS' PRODIGY 2M SAILPLANE. Lee Murray. The kit's features were very impressive: 1/64 plywood on all trailing edges, wing fairings, carbon fiber spar laminates, machine cut parts galore including the fin sides with holes pre-drilled. The parts were packages so as to minimize warpage and organized well. The plans were clear in most places with several blown-up detail sections. The nine page Instruction book was detailed to an impressive level.

In short, the kit met the highest standards of the industry. While the sailplane is targeted to the advanced builder-flyer, I believe that it is actually easier to build than some lower level models because of the prefabrication, the quality of the machine cut parts and the instructions. In the course of building I found a few areas to improve, but in all the Prodigy is an excellent model.

FLIGHT PERFORMANCE: The performance of the Prodigy in the hands of its designer, Paul Carlson is truly amazing and was the reason that I purchased the Prodigy model. I saw it perform at the 85 NATS where is was up in the 2M standings. Recently at the '86 NSS contest in Madison, WI, Paul flew a Prodigy which not only was first in 2M but also best performance of the contest (2939 points). Paul's Standard Class Prodigy prototype took 2nd in its class. After the contest Paul did some hand launches with a 3/4 scale Prodigy (HLG) to the amazement of those present.

My Prodigy flew perfectly from the first hand launch. In normal air, there was no tendency to tip stall and the pitch stability was very good, at least with the initial CG set up. In lift, the Prodigy gives plenty of indications of that lift with the nose pitching up and wings turning away from the lift. This requires that the flier pay attention in order to fly smoothly. The contest performance in my hands remains to be seen but my expectation is that it will be a super performer In two meter thermal duration events. The Prodigy can stall on launch so give it a little down trim and release straight ahead.

I suspect that the keys to the Prodigy's performance are the selection of the Selig 4061 airfoil, computer optimized for a model of the size and speed, and the attention to drag producers in normal designs.

STABILIZER CONSTRUCTION: The trailing edge l/16 balsa laminate pieces were already cut and the instructions were to cut them out of 1/16 sheet. The telescoping 1/8 and 5/32 tubes were to be glued together, but I Telt It was easier and more certain to solder them together. The instructions for the sheeting seemed to indicate that there was 2 in wide 1/16 sheeting, which I didn't find. The leading edge sheeting was provided In such excess that the stab sheeting could have come from the LE sheeting. I also added some 1/16 sheeting to the tips for a better shape for the wingtlps. I could hardly believe that the both stabs before covering weighed less than an ounce - the rudder only 8 grams.

THE RUDDER: This construction was a little confusing. Where it calls for 1/8 balsa for the frame I suspected that I should use 3/32 in many places, so I did. These included the horizontal frame components. Also I made the gusset near the control horn out of 3/32 stock vs the 1/8 stock recommended. A subsequent conversation with Paul Carlson brought out that the control horn was intended to be Inset to the 1/8 gusset. The bottom frame member was also covered with 1/16 x 1/4 strips for preserving the contour of the rudder.

THE WING: The wing instructions were more complete than with the stabilizer and rudder although there could be some clarification at a few points. One such area was where to find the spoiler tubing. It was hiding inside the blue outer tubing for the stabilizer control cable/tubing. A potential problem was noted with the dihedral angle obtainable when installing the joiner tubes. The sheer webs were a little small when compared to the plan and possibly a little small with regards to the ribs. I took a measurement of what I could get as far as a dihedral angle without more sanding or grooving of the spars and that turned out to be 2 degrees vs 3 degrees. I calculate the Dihedral Equivalent Angle I would get assuming that there would be no problem with the polyhedral joint and that came out to be 7.2 degrees vs 8.2 If I had all the dihedral specified in the plan. The Vertical Tali Volume Coefficient came out to be 0.024 which is very generous and about the same order of magnitude as the Olympic 650 - no problem. A check of the Sideslip Instability Factor was -.00115 which justified a dihedral equivalent angle of 6.2 degrees. In my estimation there is no problem with the loss of one degree In the dihedral angle.

Sanding of the leading edge is really aided by making a cardboard template negative to aid you in knowing where to sand and not to sand. Very little sanding Is needed on the lower leading edge and considerable sanding needed on the upper leading edge. If you want the magic of the Selig airfoil you must do your best here..."

Supplementary file notes

Review.

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