We saw our first Sig Spacewalker three years ago at the Hamilton Hawks Four Stroke Rally. There, O.S. President Mihara, was flying his and it was impressive. The Spacewalker is big, classic in design and flies beautifully. Phil Good, a professional model builder from Parkland, PA. and I decided to review the Spacewalker as a joint effort. Phil is a superior builder with exceptional speed. He would do the basic construction and I would do the radio/engine installation and flight testing. This is the first in a series of I.M.A.A. "legal" aircraft that will be reviewed in future issues of High-Flight.

The full sized Spacewalker was designed by Jesse Anglin, Hendersonville, NC as a personal fun plane and it flew in 1986 for the first time. It's low wing, open cockpit taildragger look so impressed Hazel and Maxey Sig that they visited with the aircraft's designer in December, 1986. They ordered their own Spacewalker and after receiving the parts had the first one completed, other than Jesse's, in just 12 weeks. Sig's R/C version was soon to follow and the rest is history.

The kit is very complete including a hardware pack, 32 page building and flying instruction booklet and lots of wood! This is a true balsa built up kit and that explains the prediction of Sig that "most of the models built from this kit will end up weighing about 20 1bs, giving a wing loading of 25.6 oz./sq. ft." Phil used Satellite City's UFO CA adhesives throughout the assembly program and he loved the fact that they are "odorless." They also lend themselves to building a light model.

The construction starts out with the wing and we began with the subassemblies as noted in the instruction booklet. There are no surprises and we progressed quickly to the point of checking the center joint for trueness of the leading and trailing edge. Then we glued the glass wingtips in place using CA and baking powder for a gapless joint ... on to the tail assembly which was very straight forward.

Construction note: The aluminum slide joints took a lot of drilIing and tapping. It would be great if the factory would pre-driIl and tap these parts.

Fuselage construction covers seven pages in the manual and took the most time completing. While not difficult, in fact it is very much like building a full scale "Experimental," it is labor intensive. The sides and framing are constructed by laying 1/4" balsa "sticks" on the plans where a lot of the construction takes place. You work your way from front to back making sure everything is straight. The front deck is sheeted by using 3 1/8" x 4" x 21" balsa planks. They are damped with a water spray and gently bent over the formers. We used tape and pins to hold these pieces in place until they dried. The landing gear is made up of 3/16 inch steel. The ends are wrapped and soldered.

Sig is one of the few manufacturers that include neat little wood pieces that help guide you through construction like the "Wing Saddle Carving Guide." You use this guide to find the perfect angle for the wing to seat properly on the fuselage. It took Phil about 2 hours to complete this procedure. The landing gear is assembled from 3/16" wire and when I asked Phil how it went together he said "no big deal" just line it up, wrap them with wire and solder securely. See the bell crank system for the rudder. Build this very strong.

When I received the Spacewalker Phil had put about 100 hours of time into it. It was covered and painted with K & B epoxy in red and white. The typical I.M.A.A. er can expect to have about 150 hours into a Spacewalker but it is worth the time.

I installed a JR PCM 10 radio system from Hobby Dynamics. The JR line is available from most hobby shops and is gaining in popularity across the U S. I installed JR's High- Speed 4031 servos in the ailerons, rudder and throttle. For the elevator a 4011 Heavy Duty JR servo was mounted since it has about 70 ozs. of torque.

Since the I.M.A.A. Safety guidelines, Section 5A-D suggests" on-board batteries shall be 1000 MAH up to 20 lbs., 1200 MAH to 30 1bs, 1800 MAH to 40 1bs and 2000 MAH over 40 lbs., I made a call to E.H. Yost batteries in Sauk City, WI. Yost specializes in nicad battery packs and have earned the nickname of "Mr. Nicad." I spoke to Mary Yost and after explaining what I would be doing she recommended a 1500 MAH battery pack. Better to have a little more juice than necessary when you fly a giant.

Finally, the powerplant. Because of the Spacewalker's scale look, we wanted to use an engine that had a realistic sound combined with enough power to make the model fun to fly. Our attention went to Saito and after trial fitting both their 300 twin carb and the 300 single carb powerplants, we chose the single carb model. This was purely for ease of installation since the twin carb 300 has the two intake stacks pointing straight back. With a "deadline" rapidly approaching we chose the easy way and bolted the single carb 300 on with a matching Tru-Turn spinner that is made for the Spacewalker.

With a twin you have to split the glass cowl. T & D Fiberglass was contacted concerning the best way to do this and after speaking with the owner, Steve Durecki, we decide to use one of their replacement units. It weighed 2 ounces less then the original one and required no filling because there were no pin holes! Nice stuff.

After the cowl was modified the engine was boxed up and shipped to Bill Carpenter of C & H Ignitions, Riverton, Wyoming. After working with several large twin four stroke model engines, we have come to realize that an ignition system just makes sense. They are easier on the engine, you get more power and they are easy to start. An engine equipped with a C A, H Ignition will idle at a much lower RPM and the hesitation from low speed to high is gone.

Three weeks later the engine arrived and was installed. We weighed the complete model with, radio (including 1500 MAH battery), Saito 300 with ignition system installed and empty fuel tank. It came in at 19.8 pounds ... perfect!

While the Sig literature states that " The Spacewalker has proven to be one of the most exciting models that we've ever flown." the three pilots who flew the model during our test described it as "fun to fly", "performs neat rolls!" and "it never has you wondering what it is going to do next ... very predictable on power and during landing."

For further information on products used in this review contact your local hobby shop or:

   Sig Manufacturing, Montezuma, IA 50171 - Spacewalker 
   Hobby Dynamics, P.O. Box 3726, Champaign, IL 61826 
   JR Radio Systems. 
   United Model Distributors,301 Holbrook Dr., Wheeling 
   Illinois 60090 - Saito 
   Tru-Turn Spinners, P.O. Box 836, S. Houston, TX 77587 
   T & D Fiberglass Specialties, 38624 Mt. Kisco, Sterling 
   Hgts., MI 48310 - (313) 978 2512 - Cowls 
   Phil Good, 1120 Hulmeville, Parkland, PA 19047 Phone 
   (215) 741 0433 - Custom Built R/C Aircraft