This item is discontinued.

GREAT PLANES SPACEWALKER ARF
PRODUCT REVIEW
by Ben Strasser

SPECIFICATIONS
Name: SPACE WALKER
Aircraft Type: 1/4 Scale Semi-Scale ARF
Mfg. By: Great Planes Model Mfg. Co., P.O. Box 788, Urbana, Illinois 61803
Mfg. Sug. Retail Price: $349.99
Available From: Retail Outlets
Wingspan: 79 in.
Wing Chord: 13-1/2 in.
Total Wing Area: 1066-1/2 sq. in.
Fuselage Length: 54-1/2 in.
Stabilizer Span: 23 in.
Total Stab Area: 184 sq. in.
Mfg. Rec. Engine Range: .61-.75 2-stroke, .70-.91 4-stroke
Rec. Fuel Tank Size: 14 oz. (Supplied)
Rec. No. of Channels: 4 (5 for Flaperons)
Rec. Control Functions: Rudder, Elevator, Throttle, Aileron

Basic Materials Used In Construction

Fuselage: Balsa & Ply
Wing: Balsa
Tail Surfaces: Balsa
Building Instructions: No
Instruction Manual: Yes (21 pages)
Construction Photos:Yes

RCM PROTOTYPE

Radio Used: Futaba 7 ch./5 servos
Engine Make & Disp.: Enya .91 4-stroke
Tank Size Used: 14 oz. (included)
Weight, Ready to Fly: 152 oz. (9 lbs., 8 oz.)
Wing Loading: 20.5 oz./sq. ft.

SUMMARY

WE LIKED THE:
Complete kit - ARF, accurate fitting parts, fine fun-flying plane.

WE DIDN'T LIKE THE:
Minor problems (see text).

There's no doubt about it, ARFs keep getting bigger and better. And, the Space Walker is a prime example of that trend. Carefully packed and shipped in a photo-emblazoned box measuring 10-3/4" x 14-3/4" x 34-1/2", all of the parts are sectioned off, bubble-packed and/or taped down to avoid any shipping rash. As a result of that care, we found no damage to anything included in our kit. (Are ARFs really a kit, or should they be called something more than that?)

Great Planes' ARF Space Walker is their balsa built-up 1/4 scale semi-scale version of Jesse Anglin's '86 tribute to the open cockpit homebuilts of the 1930's. Jesse Anglin is reported to have commented that the plane flies so smooth; flying it is like walking in space, hence the name Space Walker. Relatively light wing loading, barn-door ailerons, a thick cross-section wing, semi-symmetrical airfoil with a tad of dihedral and a blunt wing leading edge all add up to a predictable performer that's a joy to fly.

Here's what we found as we "unplugged" the parts from the box. First, there are the wing panels, which are completely assembled. They are covered with Cub yellow MonoKote and trimmed with red MonoKote in the familiar Space Walker sunburst pattern. (That's regular MonoKote over MonoKote, not the adhesive-backed trim material.) Hinge slots are factory-cut. The ailerons are taped in place onto each wing panel for transport purposes. There is a servo well in each panel along with a servo wire "fishing string." ABS plastic wingtips are painted to match the yellow covering.

The servos were moved forward on our review model to help attain the recommended C.G. without adding lead to the nose. Note micro switch on throttle servo for on-board glow.

The fuselage is also completely assembled and covered with Cub yellow with red trim. You'll also find a preformed smoke-gray windshield and plastic cowl that is factory-painted red to match the covering (and the color does match perfectly). The tail feathers are also covered in MonoKote with hinge slots factory cut. In the box we also found prefabricated piano wire landing gear with covered side plates provided, main gear wheels, assembled wheel pants painted red, a tail wheel strut and wheel, an adjustable engine mount, a 14 oz. fuel tank, plastic wing bolts and mounting brackets, a plastic spinner, pushrods and servo linkage, miscellaneous screws, nuts and bolts, wheel collars, clevises, and so on. In other words, just about everything you'll need to assemble the plane and get airborne except the R/C system, engine, prop, spinner, some CA and fuel is in the box.

Assembly:
Before we got started assembling the plane, we wanted to tighten up the MonoKote covering. Using our iron and heat gun, all went fine until we got to the tail feathers. The bays on the elevator, stab, fin, and rudder are so well sealed that, when we'd heat the covering in a given bay, it would balloon out. Under these circumstances, we'd normally make a pin hole in the bottom side of each bay to vent the heated and expanded air. In this case, however, we didn't want to make any holes in the fine covering job so a tiny vent hole was drilled into each bay through the balsa at the hinge line edge. That worked fine. When we were through, we just put a drop of thick CA into the holes to seal them.

Wing:
With the covering looking tight as it should be, we were ready to begin assembly. After laminating the two main and two aft wing joiner spar pieces together, the first step is to cut the MonoKote from the wing bolt, wing dowel, servo, and servo wire exit holes. Then, after the servo cord exit hole is cut through the covering (the hole is already cut through the balsa), the servo wire "fishing" cord is passed up through the servo wire hole provided in the top of the wing. Then, it's time to join the wing panels. The dihedral is built into the root ribs and wing joiners. When we trial-fit the wing panels together, the root ribs fit together perfectly. And we do mean perfectly!

The wing is completed as the wing hold-down dowels and ply wing bolt doubler plate is glued in place. Contrary to the sequence outlined in the assembly instructions, we didn't add the wingtips until the wing was completed and servos and linkage installed. That way, if weight is needed for spanwise balance, it can be added to the tip end wing rib and hidden under the wingtip. (It happened that with this plane, no weight was needed!) Then the plastic wingtips were added.

When gluing the wing bolt plate doubler to the wing and stab to the fuselage, some of the MonoKote must first be removed so the adhesive bonds to the balsa, not to the covering. Whatever you do, do not cut into the balsa. Some years ago, we "discovered" that only a 1/64" deep cut into the balsa of a stab on a different ARF caused a stab panel failure when flying a loop. Fortunately, we got it down okay with half a stab. Now, we use the tip of an X-Acto blade to "catch" an end of the covering, so it can be pulled up to be cut off with small scissors or by laying a straightedge blade flat on the surface while holding up the covering to be cut. Don't worry about getting those nice straight edges under the plate as shown in the photo. But do avoid cutting into the balsa at all costs.

The last step in working on the wing is to finish and install the landing gear. The landing gear side plates are clamped to the prefabricated landing gear using the nuts, bolts, and plates provided. When installing the wheel pants, note that there is a "dimple" on each side. Only the inside dimple (make a right and left) is cut out for the axle while the outer dimple remains as is to center the other side of the wheel pant on the axle. The wheel pants' brackets provided in the kit had a sloppy fit on the axles, so we used some other mounting brackets we had that fit the axles properly. While 2-1/4" wheels were included in the kit, we found that 3" wheels will also fit the wheel pants fine (just in case you fly from a grass field). Some "tweaking" of the main gear axle was needed to get the caster and camber for proper ground tracking.

Fuselage:
In checking the fuselage, we were quite surprised to find that the front and back of the firewall and fuel tank compartment was already sealed to prevent fuel soaking. That's the first time we've ever seen that in an ARF! Work begins on the fuselage with the installation of the engine mount. Tick marks on the firewall along with an engine mount template help you get it right. Plastic wing bolt hold-down brackets are installed inside the fuselage using factory predrilled holes to get them located properly. And they fit the wing bolt holes perfectly - as did the holes in the bulkhead for the wing dowels. Before we started working with the plastic cowl, we covered the entire inside of the cowl with overlapping strips of 3/4 oz. glass cloth. A light coat of 3M contact adhesive, sprayed onto the strips of glass cloth before they were applied, held the glass cloth in place while the CA was put on. We then added a second layer of glass in the area where the cowl hold-down screws were located. That small investment of time assures that no vibration cracks will show up later on.

Marking the cowl for the engine cutout is always a very risky job. What you cut away can't be put back! The approach we've been using lately is to locate the cowl on the fuselage with 1/16" space behind the spinner backplate. Using a non-permanent transparency marking pen, we make cowl registration marks on the fuselage. With the cowl removed and engine in place, we get out a piece of clear transparency material (or clear acetate) and hold it in place over the engine, marking the cutout required. We also put the same cowl registration marks on the transparency material. Then, we use an X-Acto knife to make the cutout in the transparency material and check it out on the engine. When all looks right, we use the registration marks on the acetate to align it on the cowl to accurately mark the cutout. Of course, some additional fitting has to be done on the cowl because it has to slide on over the engine, but the transparency approach has given us the best cutouts we've done so far.

Before the MonoKote is cut from the elevator and rudder servo exits, note that a rudder exit is provided on both sides of the fuselage. Only one rudder exit need be cut out unless you decide to install pull/pull rudder cables.

To install the stab and fin, the covering will have to be cut from the slots in the fuselage. To avoid having the glue joint show (an ARF give-away) we make a cut in the covering down the center of the slot with an angle cut to the corners at each end. Then, we fold the covering open (like double garage doors) to slide the stab or fin in place. After the glue has set up, the covering is then ironed down over the glue joint so it looks neat. That also protects the glue joint from fuel contamination.

Both the stab and fin fit perfectly. No sanding or shimming of their respective saddles was required. All we needed to do was to "square" the stab to the fuselage in top view and align the back of the fin with the fuselage. Instead of installing the tail wheel tiller arm into the leading edge of the rudder as recommended, we attached it to the bottom of the rudder with a metal clip. A short length of rubber fuel tubing slid onto the tiller arm offers some shock-absorber quality to the tail wheel. Setting up the tail wheel in that manner is not a recommendation, it's just a personal preference. While this technique is easier to set up, it also makes it easy for us to replace the tail wheel strut at some time in the future, if we need to do that without de-hinging the rudder.

In checking the muffler set-up for our Enya .91, we found it would fit nicely inside the cowl with only a small added cutout in the cowl bottom air exit. We also added one of Great Planes' fuel filler valves to make the job of fueling more convenient. A hole was cut in the side of the cowl to accommodate that handy device.

One other thing: while not included in the kit, the instructions point out that a cross member should be added across the fuselage to assure that the fuel tank will stay in place. We installed our fuel tank hold-down bracket with screws so we can easily remove the fuel tank in the future, if needed. We also glued a block onto the inside back of the firewall to support the front of the fuel tank. Some foam was used at the front of the fuel tank where it would otherwise contact a vibrating surface.

Radio Installation:
To control our Space Walker, a Futaba 7 ch. radio system was installed using five servos. A ply servo tray is provided at the back of the servo compartment which even has doublers in the area of the servo hold-down screws (that's another first in ARFs for us!). When checking the C.G. with the engine and R/C equipment in place, however, we found that the plane was tail heavy. To avoid adding more weight than necessary, we moved the servos forward to the back of the bulkhead just behind the fuel tank. We also installed our 1000 mAh battery pack in a nest of foam under the fuel tank just behind the firewall. It turned out that with the addition of an on-board glow battery, the C.G. was right on! That battery is also located in a nest of foam under the fuel tank. (Lots of room there.)

Because we had moved the servos forward, the wire throttle pushrod included in the kit wouldn't make the "S" bend required, so we switched to cable. The balsa rudder and elevator pushrod worked fine - though supports were added at the back of the servo compartment to minimize any vibration. The elevator pushrod uses "Y" clevises at the control surface end. That's ideal because it enables the pilot to make fine adjustments of the elevator halves as needed to fly inverted and vertical maneuvers just the way you want them.

Two aileron servos are required. The "fish string" makes it easy to route the servo extension down through the wing. The servos can either be connected with a "Y" to the receiver or they can be set up in separate channels (so flaperons are possible) if you have a computer radio.

Finishing:
With this ARF there isn't much left to finish. We painted the cockpit with black dope, both for looks and for fuelproofing. The kit includes cockpit coaming, which went on very easily and looks great. A scale fuel level fairing (provided) was glued to the top of the fuselage as shown in the assembly booklet. A formed windscreen is also included. When cut to size using the marks provided, we felt it was much too high, so we cut it down somewhat. Note that there is a center mark on the windscreen that helps locate it properly. While it certainly could be glued to the fuselage with an R/C 56-type glue, we decided to screw it down with button screws. Small ply doublers were added inside the fuselage for the screws. We also added some striping tape to the wheel pants to jazz them up a bit. And while the kit does include a plastic spinner, we prefer the look of Tru-Turn aluminum spinners. Recently, however, we saw a fellow flying a Space Walker at a local flying field. He used only a prop nut instead of a spinner, and the plane looked very good that way too. Actually, we preferred that look to the look of the spinner.

Flying:
In preparation for the first flight, we had checked the wing loading, rechecked the C.G., and ran several tanks of fuel through our Enya .91. We noted that our wing loading came out a bit more than what we found in the ads. Perhaps that's because we put the .91 up front - though 20.5 oz./sq. ft. is still relatively light wing loading for a power plane. (The sister ship we mentioned earlier with the prop nut was flying with an O.S. 1.20 4-stroke and it handled and flew very well.) The control surfaces were set up to the low and high rates as outlined in the assembly booklet. With the help of a friend to hold the plane, the engine was started and run up while we checked and rechecked the R/C operation. Since everything looked fine, we put the plane down on the taxiway and drove out to the take-off spot on the runway. First we did a short taxi test, however, to check out the ground handling. All was okay so we taxied back to the take-off spot, turned around, then started opening the throttle.

Rolling down the runway for the take-off, we gradually opened the throttle to about half throttle - which seemed more than enough power. Only a bit of rudder was needed to keep it on track. The tail came up nicely, then with a smooth lift-off, it was airborne. A little more up elevator and it climbed out with ease.

After a couple of smooth-flying circuits around the field at altitude and half throttle to verify that the C.G. was okay and that the control surfaces worked as we wanted them to, we flew a few loops and tried some axial rolls. The Enya .91 4-stroke pulled the plane through rather large loops with ease - still at half throttle! In checking the aileron roll rate, we found that the high rate was needed for anything more than a very slow roll. As a matter of fact, even the high rate gave us a two second roll. Normally, we set up the throw for a one second roll, so we made a note to increase the aileron throw when we get back to the workbench.

After several minutes of flying loops, rolls, and such, we throttled-down to check the slow flight characteristics of the plane. Flying slower and slower while dragging more and more up elevator, the plane finally stalled by dropping its nose for a few feet or by making a slight banked turn to torque side, then flattening out again. There was no evidence of a killer tip stall and that's really good news.

As preparation for the touchdown, we flew a couple of touch and goes. One thing we discovered was that a tad of rudder is required to keep the plane on heading during both the touch and go as well as during the landing. The landing approach was smooth and sweet - as was the touchdown. Now that was one nice flight, although we had to do some minor rework on the left main gear wheel that had somehow tightened on the axle.

For the second flight, after enjoying some more loops, axial rolls, hammerheads, Split "S" and such, we decided to see how (if?) the plane would spin. Up at altitude, we started slowing it down while dragging more and more up elevator. At just about the moment before the stall, we hit full right rudder. All we got though was a nice slow spiral dive. Not that time. With the rudder at low rate, we couldn't get the Space Walker to spin. When we tried the same thing with the rudder set up at high rate, we did get a nice clean nose-down (rather than flat) spin. After four or five spins when the controls were neutralized, it flew out of the spin in less than one turn! Parenthetically, we were still flying the throttle-required maneuvers like the loop, hammerhead, axial rolls, and so on at roughly half throttle. There's no question that the Enya .91 4-stroke is plenty of power for the plane. We don't see the need for a 1.20 4-stroke unless, for some reason, the plane turns out to need lots of weight up front and you would rather put the weight in more engine than lead!

Anyway, we are very pleased with the performance of the Space Walker. It will fly the maneuvers, yet it is a very smooth, stable, and predictable performer that's just a relaxing joy to fly. Incidentally, while we had the plane at a local club flying field for our test flights, more than one R/C pilot came up to admire the plane and commented that it was a plane they wanted because of "that real airplane look." Having seen it fly, they were convinced! When we told them that it was an ARF, they really thought we were kidding. Only you (and they) know for sure.

Conclusion:
Great Planes' ARF Space Walker has the look and feel of the "real" airplanes of the hey-day of flying with an open cockpit, a semi-symmetrical smooth handling airfoil, barn-door ailerons, conventional gear, and wheel pants. There are ply doublers for the servo hold-down screws, the cowl, wheel pants, and wingtips are factory-painted to match the MonoKote covering. The landing gear comes prefabricated, the firewall and fuel tank compartment are fuelproofed, the wing bolts actually align with the hold-down screw bracket, and on and on. There's no doubt that Great Planes has taken the time to do it right. And the easy-to-follow assembly instructions help assure you'll get the plane put together the right way. To sum it up, Great Planes' Space Walker is a superbly crafted ARF that looks great on the ground and even better in the air. As you probably have guessed by now, we give the Space Walker a high flying Ten Star recommendation for ARF design, another for ease of assembly, another for looks, and another for the way it flies. And we like it too.

If you haven't thought about getting into 1/4 scale, this one may well get you thinking. If you are thinking of getting into 1/4 scale, the Space Walker is certainly a great way to do it. If you are already into 1/4 scale, the Space Walker is one you'll want to add to your fleet. Take a walk in space and you'll enjoy every minute. Available at local hobby shops, Great Planes' ARF Space Walker lists for $349.99. Check around and you should be able to beat that price by a few $$.