This item is discontinued.

GREAT PLANES SPACEWALKER ARF
PRODUCT REVIEW
by Stephen E. Adams

Aah, to enjoy a little Christmas in the summer time. That's what I felt with the arrival of the Spacewalker at my door. Kind of made me want to cancel the weekend's camping trip with the wife and kids and hole-up in my shop. But I am smart enough not to utter that suggestion. Let's see what's in the box.

The Quarter-Scale Spacewalker is Great Planes' recent entry in the high quality, large scale, ARF market. In fact, this Spacewalker is suitable for IMAA competition with upgraded pushrods. At the tape it comes in at 79 inches and weighs in at 7 lbs. 2 oz. with a Saito .91 under the hood.

The MonoKote finish is wonderful with the compound curves looking better than what I normally achieve. As expected, the covering needed to be gone over with a heat gun and iron to remove wrinkles. One issue is that the sheeted surfaces were apparently not prepared with a "Woodpecker" resulting in trapped air bubbles and some difficulty in removing those wrinkles.

The process begins with a detailed inventory of parts and a comprehensive reading of the instruction manual. Yes, I do read the manuals and many times I find something revealing in the "Expert Tips" that help my future projects.

The Spacewalker takes a typical approach to ARF completion so let's break out the epoxy and get some stuff messy. I suppose that reveals too much about my own shop habits there. Oh well. We start by joining the wing sections with the two laminated plywood joiners. Oh, did I mention that the joiners have the dihedral built-in? They do...and to top it off the wing root ribs are set in at the appropriate angle so no need to sand here. I personally appreciate that.

Another nice feature is the string run through the wing sections to assist in routing servo leads. Prior to joining the wing sections you must re-route the string exiting the root ribs. Simply locate the small hole on the top of the wing, cut away the MonoKote, and using tweezers pull the string up through the hole. Re-use the tape and secure the string to the wing surface.

After the wing is joined epoxy the two dowel pins into the pre-drilled holes in the leading edge. The wing is then mated to the fuselage using the dowel pins and the supplied wing mounts. These nylon mounts are merely bolted onto the sides of the fuselage interior and not keyed into any formers and I am concerned whether this system will withstand many punishing landings. The fuselage side is a lamination of plywood and balsa and the instructions warn you to not over-tighten the bolts and crush the balsa exterior. I suspect that a hard landing or two is going to have the same result. I would encourage you to consider using some light ply on the exterior of the fuselage as a bolt plate to distribute any stress.

The kit includes fiberglass wheel paints and engine cowl. While the manuals references plastic parts kudos to Great Planes for the upgrade. Plastic parts are so fragile and usually a pain to work with. Mounting the wheel pants is straightforward as long as you have some long-nose pliers or forceps to reach into the pants and install the outer wheel nut. Not hard but may take a few shots to get it on the gear wire.

The landing wire is pre-bent and heavy duty. It should take the punishment that I sometimes dole out on landings. Again, I reveal too much about myself. Because the gear is mounted directly on the wing underside and crosses the root ribs it is bent to account for the dihedral of the wing. This process forced me to break out my rotary tool and make some adjustments. The forward strut matched the dihedral perfectly and fit into the hardwood rails with ease. However, the aft strut did not match the wing dihedral. It appears that when they joined the two pieces of wire the aft strut portion was rotated slightly. This meant that the dihedral bend in the wire was not up and down relative to the wing but fore and aft. I had to grind out some of the hardwood rail to get the wire to fit correctly. Be careful that you do not grind away too much of the rail so you have a place to screw on the nylon gear straps. For the record I did try to bend (rotate) the wire but that proved to be tough and I really did not want to fight it. With luck, quality control will eliminate this in the future.

Now onto the tail feathers. After cutting away the MonoKote and removing a balsa spacer the stab is glued into place with 30-minute epoxy. Be sure that the stab is properly aligned and centered before the epoxy cures. Do not cut away the covering at the very back of the fuselage where the vertical fin adheres. When you insert the vertical fin from the top that will be the covering for the exposed balsa of the lower portion of the rudder. If not you should be sure to fuel proof any exposed balsa. As with the stab ensure that the alignment is correct and is 90 degrees perpendicular to the stab.

Mounting the servos is an easy matter with pre-installed rails in the fuselage. The manual suggests using standard servos (Futaba S3003) with the exception of the elevator. They recommend a larger output servo because the single pushrod drives both elevator halves. This is accomplished using a wire/dowel/wire pushrod that has two wires on the downhill side. One wire goes out one side and the other wire exits the opposite side so that each elevator half is actuated simultaneously. I don't particularly care for this method so I built another pushrod and added a second elevator servo.

You must construct these pushrods yourself and this is a simple matter with all of the material included in the kit. The pushrod is a free-floating wire-dowel-wire format. At this point you may want to make a change if you fly in IMAA events. All pushrod wire should be 4-40 so the 2-56 wires will need to be replaced.

The fuselage former sitting immediately in front of the stab is in the way so I made offset bends in the pushrod wires to exit the fuselage cleanly. I would recommend the 4-40 wire upgrade in this case to minimize the bending and flexing of the wire under load.

I chose to use two elevator servos instead of one large-scale servo to drive both sections. If you use a single elevator servo the pushrod will have two wire sections from the tailwind side of the dowel. By doing this I needed to relocate the throttle servo. I simply built a small frame and mounted it to the former behind the fuel tank. I used a Hobbico CS-61 servo for throttle duties.

Next I installed the receiver and routed the antennae by drilling small holes in the formers and threading the antennae through them. I fished the antennae through a hole I drilled on the fuselage bottom and secured it to the underside of the aircraft.

The Spacewalker included a Great Planes adjustable engine mount and a paper template for alignment. The firewall, which is already fuel-proofed, is embossed with crosshairs so align the corresponding crosshairs of the template, tape it into place and drill your holes for blind nuts.

Accessing the rear of the firewall is easy since this is a large aircraft. After setting the nuts I adjusted the mount to fit my Saito .91. I then needed to mark the holes for the engine lugs. I make those using a piece of torch-heated music wire that neatly fits into the lugs. I get nice "melted" starter holes. I finish the holes with my drill press and then tap the mount for threads. I prefer not to use the sheet metal screws provided in the kit but use socket head machine screws with lock washers and then secure them with nylon insert locknuts on the backside.

The pictures in the instruction manual depict the engine mounted in a horizontal configuration and while I use this myself often I opted to install the engine inverted this time. Why you may ask? Well, the engine cowl is large enough that I can completely enclose the engine AND muffler with an inverted installation. My father-in-law modified the header pipe on the Saito from a 45-degree bend to a 90-degree bend to keep the muffler inside. All nice and neat!

In order to access the now-hidden glow plug I built a remote glow setup using instructions from a recent article in another publication. I run the wires through the firewall and mounted the plug in the cockpit. Easy to build and cheaper than buying them outright!

The firewall has a large (1") hole to pass fuel lines through the center of the engine mount. You will need to cover this hole by cutting a small piece ply, drilling holes for the lines, and gluing it into place. Make sure to fuel proof this piece of wood.

The kit refers to a "pre-installed" Great Planes "Easy Fueler" but it did not exist. No matter. I installed an Easy Fueler to the firewall and cut a small hole in the cowl to access it.

The kit includes a fiberglass engine cowl with color-matched paint. As we all know there is no such thing as truly accurate color matching between our covering material and painted parts but in this case the match is very close. My only recommendation to Great Planes is that they increase the thickness of the gel coat ever so slightly. You can see the fabric pattern through the gel coat. You would never see it from several feet away but up close it is rather obvious.

The scale intake vents on the engine cowl were enlarged to ensure adequate cooling airflow for the Saito. The airflow exit is molded into the cowl and simply cut out with a cutting wheel on my rotary tool.

The fuel tank is an easy installation since there is plenty of room to work with. I ran my plumbing, wrapped the tank in foam, and secured it with a scrap piece of balsa stick.

I set all control surface throws according to the instructions and then checked the C.G. I was surprised at the amount of lead needed (roughly 8 ounces) to reach the recommend center of gravity especially since I put the largest recommended four-stroke engine on the front.

Time to head to the field and see if she files as good as she looks. I arranged to meet Richard Helm at the field since I can be a coward at flying my own birds the first time out. However, the concern was not warranted. Richard has a Spacewalker of his own but it has not flown yet so he was anxious to see what was in store for him.

It was a beautiful Saturday afternoon with the temperature about 75 degrees and southerly winds about 10mph. There is always wind in Oklahoma...get used to it or get a new hobby. With the Saito .91 inverted we stood the plane up on one wing tip to make the starting easier by avoiding flooding or the damaging hydraulic lock. It started easily since this engine is well broken-in and we confirmed the mixture settings. Everything looked great.

Richard taxied out and began his rollout only to have the first glitch. Both wheel pants came loose. As we all know pants look great on a plane but can sometimes be a real pain...especially if you fly off grass. When I saw Great Planes design I thought it was one of the better attachment methods. However, as we tried to re-tighten the screws they stripped. So, off came the wheel pants.

We started up again and off she went. Only a minimum of right rudder was needed as it accelerated and just a touch of elevator lifted the Spacewalker into the sky. As it climbed out it continued to climb and climb and climb. It took about 8 clicks of down elevator to correct. We'll check that one out later.

The ailerons impact was very crisp so a soft touch is needed...use some Expo if your radio is so equipped. That is surprising since the ailerons are not that large. With such a large wing area axial rolls are slow and easy on low rates with only a hint of down elevator as it passes through inverted. The rudder's impact is also crisp as the yaw quickly rolled the wings over. Again a soft touch is needed here. Neither of these situations are an issue to experienced pilots. This is simply a warning for the less experienced.

Richard rolled to plane inverted and it flew hands-off with only two clicks of down elevator. We were both impressed. Stall characteristics were gentle and straight ahead so no real concerns there. Great Planes put a nice airfoil under this bird.

The Spacewalker landed slow and graceful with a nice two-wheel landing. I decided to head back to the shop, verify everything, and make a few changes before tomorrow's flight.

Back at the shop I re-attached the wheel pants by drilling and tapping for 6-32 socket head screws. I needed to increase the flat spot on the axles since I now had a larger setscrew.

Next I looked into why the plane wanted to climb. With the down trim set the elevators were noticeably down so I knew I needed to look elsewhere. First, I verified the incidence on both the wing and the stab and they both looked on the money. So I chose to add some down thrust to the motor. As we know the right thrust is built-in to the firewall but there was no design consideration for down thrust. I loosened the motor mount bolts and slipped in a flat washer and cinched everything back up. With the plane re-assembled I was ready to go out the next day.

On Sunday afternoon the temp was in the low 70s and the wind had increased to 12-15 mph with some strong gusts. I flew my Eliminator for a while to get my thumbs, and nerve, into shape. Needless to say that a downwind engine-out and the subsequent lousy landing, if it can be called that, in the tall grass separated the landing gear from the fuselage.

Now that the time was forced upon me I prepared to fly the Spacewalker. I fueled it up and taxied into position only the kill the engine with my thumb. I hate those walks. With the assistance of club president Norm Brewer we restarted the Saito and got back into position.

After tuning out the advice echoing from the pits I began my acceleration run. After over-correcting on the rudder I quickly chopped the throttle before I ground-looped. I took the time to make a couple of short runs to get the feel of the ground handling. It really handles nice on the ground I simply got heavy-handed with it.

On the next run-up I let the tail come up at 1/3 throttle and the Spacewalker lifted off at slight less that half throttle. No power shortage here but I increased the throttle to full for the climb-out.

I ran a few laps around the field and confirmed Richard's comments about the sensitive ailerons and rudder. The Spacewalker still wanted to climb but this time it did not need as much down trim so I knew I was headed in the right direction. Another flat washer between the motor mount and firewall should set things right.

After running through some simple aerobatic maneuvers such as axial rolls, stall turns, and some split-S, it was time to shoot some approaches. I wanted to check the glide slope and see how well it slowed down on approach. All the approaches were shallow with simple power adjustments to control the rate of descent. After climbing through approach number three I swung around onto the downwind leg to land the airplane. I pulled the throttle back to half as I turned onto base and pulled it back to 1/4 as I came onto final. Just a touch a throttle was needed to place the Spacewalker directly in front of me with by a very nice and slow two-wheel landing.

The praises rang out from the pits along with a challenge to three-point the next landing. I warned the observers that I never mastered this maneuver even in my Great Planes Cub but a challenge was a challenge. I taxied back up the runway and took off again. I chose to fly around for a while so that maybe they would think that I was not going to attempt it.

No such luck so the time had come to put up or shut up. I made an identical approach as last time only the plane floated further down the runway. As I continued to pull up elevator to plane simply did not want to settle. It continued to float until it ran out of airspeed for a beautiful first-time-ever three-point landing. This plane is going to be a lot of fun.

Time to pack up while I was on a roll. Besides, an incoming storm front was beginning to hamper visibility.

In reviewing this project I encountered a few concerns but nothing more than minor annoyances. A reasonably experienced builder should have no problems with this ARF. I, along with my fellow flyers, was suitably impressed. In fact, our club president is ordered one and will bring the count to three Spacewalkers in our club. I see some formation flying in the future.

Overall, I was pleased with the quality of the Great Planes Spacewalker and would strongly recommend it. In fact it this be a good plane for someone wanting to move into large-scale birds. If the flyer has some experience with semi-symmetrical airfoils then the Spacewalker should be a piece of cake and a whole lot of fun. I look forward to many more flights with this one.

Thanks to Heather at Hobbico and the folks at Cyberbond for their support in this project.