Summary (Cheers & Jeers)

ARF Introduction

In the creation of their model of this classic airplane, Pacific Aeromodel Inc., PAC for short, choose the NR718Y as it was after the fateful modifications mentioned above. In their advertising PAC tries to make up for this by saying the Model Y is NOT a racer. It is easy to understand why they wouldn't want a modeler to put an equivalent to the 450hp fire-breathing monster into this airplane. No need to re-live history and shed part of a wing. PAC doesn't really claim this ARF, which stands for Almost Ready to Fly, to be a specific scale, they just call it "120 size". IMAA legal with a wingspan of 82", it is close to 1/4 scale with a 22.8% scale wingspan and 24.8% scale fuselage length.

I was looking for a ARF to act as a test-bed and break-in-stand for a RCS 140 gasoline engine. My RCS140 has had a checkered past. My first gas engine and it was giving me trouble in my Top Flight P-47. A dead-stick at the wrong time cost me the wing of that airplane. The engine was returned to RC Showcase for evaluation and came back with a new timing sensor, but otherwise unproven. Instead of risking my P-47 again, which I have invested hundreds of hours of blood sweat and tears before the latest rounds of repairs, I wanted an ARF to try it in first. The original NR718Y was designed as a test-bed for engines... and the ARF from Pacific Aeromodel seemed like the perfect choice. I've always had a soft spot for Gee Bee's and to fly one that was reported to have good flight characteristics would be a hoot. The intention is to fly the GBY the latter third of 2002 to test out the RCS140 and get it good and run-in before returning it to the P-47. Once that season is over, and if I decide to keep this ARF, I will install a new engine. Possibly another RCS140, or more likely something different (bigger). Time will tell and I will post an addendum to this review at that point.

Construction quality of this ARF is exceptional. Material selection is excellent. What appears to be Aircraft Birch 5-ply plywood is laser-cut and used through-out the fuselage, and the critical areas of the wing. The balsa is of mostly good quality. The open stringers behind the cockpit, especially the turtle-deck, could stand to be stronger/thicker in a few places and you have to be careful in handling/transporting this airplane. Everything about the model was well thought out, then well engineered and constructed. At the factory, everything was first tack glued with CA, then final gluing was done with an Aliphatic Resin type of glue, better known as wood glue. If this is what we can expect from models from China, then I say yahoo! It has raised the bar on what I considered top-notch ARF construction quality. I wish they were all built this well!

Choices To Make First

The first task on the list is to make some choices on what kind of engine and radio gear you will install. PAC recommends a 2-stroke glow engine from 1.08ci to 1.60ci, or a 4-stroke glow from 1.20 to 1.80, or a 23cc gasoline engine. This reviewer finds these to be a little on the low side of what is required. I wouldn't recommend anything smaller than something like a Moki 1.35 or OS 1.60FX 2-stroke glow, a YS 140 or Saito 180 4-stroke glow. A 23cc-35cc (1.4 to 2.1ci) gasoline engine such as a RCS 140, 3W-24, RCS 180, MVVS 2.15, or a 31-33cc weedeater conversion are also good choices. It should be mentioned the glow engines will produce a lighter weight airplane that probably flies better. The cooling tunnel built into the fuselage is designed for inverted single-cylinder engines. If you want a multi-cylinder glow engine, the new Saito 200TI in-line twin might be just the ticket. I've also heard of someone installing a Saito 170R3 radial, but there are a few minor modifications you must do to the cowl area to cool it, and I have no data on the longevity of a radial in this model. My personal preference for engines of this size is gasoline, cheaper to operate and easier to clean up. See the flight report for a few additional comments about engine selection.

Radio selection is easy. The factory suggests a high-torque 70oz or more servo on the rudder and standard ~45oz ball-bearing servos on all other control surfaces. These recommendations are fine for any maneuver the plane and pilot are capable of. Six servos are required, one for rudder, two for elevators, two for ailerons, and one on the throttle. I used the radio gear from my P-47, which worked very well. I am running a Hitec RCD3600 JR-compatible PPM receiver that has proven itself reliable. The receiver antenna is enclosed in a pushrod-tube and routed through the fuselage interior. I put a Hitec HS-645MG servo producing 133oz of torque at 6v, metal gear, on the rudder. It provides all the authority the model needs and more. I used Hitec HS-425 dual ball-bearing sport servos producing 57oz at 6v, nylon gear, on the elevator halves and the ailerons.

On the throttle, I installed a Hitec HS-85 "mighty micro" servo with 49oz at 6v, ball-bearing, just as strong but nearly a third the weight of a standard servo. Since I wanted servo control over the choke, I installed one for that too. I'm using RX channel-8 and the Aux-3 knob on the transmitter for the choke. I have been using my Sullivan Dynatron starter instead of hand-starting it, and the choke is now largely unnecessary. It is another way to shut off the engine in an emergency. The primary control for turning the engine off is the Fiber Optic Kill Switch manufactured by Electrodynamics. This is a great device that provides transmitter control of the ignition system without introducing potential interference to the receiver. It also provides an additional layer of security. If the ignition switch is accidentally turned on during handling or transport, the ignition system still doesn't have power until the receiver is also turned on. In the event of an in-flight RX or battery failure, the ignition system will be turned off automatically. All is being controlled by a JR 8103DT transmitter.

Another choice you need to make is whether or not to use the included control-surface hardware. It would probably be ok to use it as is, they are of decent quality. None of the pushrods are longer than 5" and they are quite stiff at that length. However, it is smaller than recommended by the IMAA. Not only that, the included hardware doesn't line up with the pre-drilled holes... but there is a 3mm hole drilled at the exact locations for aftermarket hardware. I used a complete MK hardware system, in 3mm (~6-32) size, including the outrageously expensive ball-bearing connections. It fit perfectly, except for the ailerons which required longer 3mm x 35mm bolts. I would use them again, but would substitute Carbon Fiber pushrods with titanium ends from Central Hobbies, in place of the MK aluminum pushrods. There is nothing wrong with the aluminum pushrods, they are very light and very strong. It's just easier to make your own pushrods exactly the length you need, without having to measure them when you order the hardware, which could be before you even have the model on-hand. Before installing the hardware, I recommend hardening the "hard points" for the control horns with some thin CA.

Before you can order servo extensions for the tail, you will also need to decide if you will use the manual's way of handling the two independent elevator halves and the rudder. They suggest that you put the elevator servos and arms in a manner where the geometry is not the same. It's probably ok this way, and allows you to use a simple Y-cable and not worry about a reversing servo. I decided that I didn't like this method and choose instead to put the servos in the same locations on both sides, turn the servo arms the same direction, run an additional extension to the RX, and mix the two channels with my transmitter. This insures perfect geometric symmetry of the control-surface movement, allows easy adjustment at the transmitter, and is working great! The manual recommends 18" extensions, but I recommend 24" versions to give you a little more flexibility in RX placement. You will need two of these, and a Y extension, if you are doing the elevator as the manual suggests. You will need three 24" extensions if you choose to mix them at the TX. I purchased all my wiring, switches, and batteries from Radical R/C. I highly recommend them.

If you install a light-weight engine, and install the rudder servo in the tail, you will probably need to add nose weight. Maybe a lot of nose weight. Instead of doing that, I'd suggest strongly considering putting the rudder servo up in front of the cockpit and running the rudder Pull-Pull. This will give you a nice scale rudder connection, and will save many ounces of nose weight. Even with the heavier RCS-140 (~3lbs ready-to-fly), I needed almost 4oz of lead in the front of the cowl, plus moving both ignition and RX batteries as far forward as I dared, to balance with all the servos in the tail. I've also seen a modeler build one of these using an Elevator Bellcrank like the ones from Central Hobbies and a single elevator servo mounted in front of the cockpit. Do what you need to do to keep from adding lead. PAC has made it easier for you to have a choice... by not pre-cutting the covering in the tail for their suggested servo placement.

Assembly

We start by going over the Parts List in the manual to determine if anything is missing or broken. It is a fairly complete list, as well as a very complete hardware pack. Make sure nothing is damaged from shipment, make note of the one-page addendum to the manual, and get ready to start assembling (can't hardly call it building)! The first thing you are going to notice when assembling this ARF is the amount of things that have been done for you already. Small things that are usually left for you to do on many ARFs. Things like hinge-slots pre-cut, holes being already drilled for you, etc. The manual itself, while a short 20 pages, contains all the information you need. If given the control throws and balance point, most modelers with experience assembling ARF's or building kits wouldn't even have to have the manual at all. A stand will be helpful during the assembly of this model. The Robart Super Stand II works great on the round fuselage.

The first step is removing all the control surfaces, which are installed but not glued, in preparation for shrinking the covering. This is Ultracote (Oracover) and as such requires a slightly different technique from Monokote. I recommend using just a covering iron set to about 325F and not a heat-gun. A heat gun, or too much heat on the iron, can cause the covering to pull back slightly at the edges... sometimes leaving an ugly white edge. Out away from the edge, it can handle quite a bit of heat. Some pressure from a soft cloth rag or glove helps insure the seams stay put. Be prepared to shrink it again after a few trips to the field during the summer... especially if you leave it in the sun all day. Just the nature of Ultracote. I added 1/8" dark-blue pin-striping to all the red/white color breaks. Looks great!

Tail Feathers

Next step is to install the tailwheel into the rudder. The included tailwheel is different from the one in the advertising, but the same as the one shown in the manual. It is of good quality music wire, and designed to transfer most all the stress into the strong bottom of the airframe and not the rudder. The slot is already cut into the rudder, as is the hole for the tailwheel wire, all you do is glue it in with 30-minute epoxy. The only changes I made here was to increase the size of the tailwheel to a 2" Klett (about my favorite tailwheel and appears to be discontinued) and I bent the wire down some more to give it a bit of additional clearance below the rudder. The factory tailwheel probably would have been ok, but looked too small to me. While the fullscale GBY had a small tailwheel, it also had a wheelpant on it which makes it look bigger. Remember to grind or file a flat-spot on the axle for the wheel collar.

The next step is to install the rudder into the fin. The CA hinges are of very good quality and the largest I've seen. There is no good reason to not use them. I usually prefer point-hinges, but this ARF doesn't have the extra wood in the places where needed. PAC gives a tip for installing the CA hinges: draw a line down the center and use a t-pin on the centerline to keep it correctly positioned. It's a good tip that I would amend to include using two t-pins along the center-line of each hinge instead of just one. Two pins keep the hinge from rotating before you get it glued. Be sure to use plenty of good-quality thin CA. These are large hinges and need more than you might be used to. From the picture, it looks like not much holds the rudder down at the bottom. Worry not, the metal tailwheel plate gets screwed into the fuselage and provides an extremely strong connection for the rudder. Install the elevators into the horizontal stab using the same method.

The manual recommends applying the decals to the tail at this point. I suggest you trim them to eliminate some of the clear around the outside. This is particularly important on the "Gee Bee" decal. The NR718Y numbers are individual decals. I suggest measuring them, and using a ruler marking two pencil-lines on the covering as a guide. One line where the top of the decal will be, one line on the bottom... kind of like the lined paper you used to use in early grade school when learning how to print. This makes it much easier to apply them straight, rather than just eyeballing it. The lines are erased with the eraser-end of your pencil after the decals are applied. All other fuselage and wing decals are already applied for you.

Wing

First step in wing assembly is to glue the ailerons onto the wing halves, using the same technique as the tail feathers. Next step is to install aileron servos. There should be a string running from the hole in the top of the wing at the root, to the servo opening, and held in place at both ends with a small wood block that is tack-glued. This is used as a pull-string to snake your aileron servo wires through the wing. Mine were missing on one side (later found them rattling around loose in the wing), and unusable on the other side (string went down the wing-tube hole instead of the openings for the servo wire). Not a big deal, a fishing weight and some fishing line had pull-strings pulling servo wires in no time. The manual suggests 12" extensions for the aileron servo wires, and a Y-extension for the receiver side. Be SURE to tape the connections or use some other means to prevent them from pulling apart. I added servo-wire-holders from Don's Hobby Shop (www.donshobbyshop.com), gluing them near the hole in the top of the wing. These hold the wires securely and make it easy to hook up before flying.

Now you can install the servos into the pre-installed rails. You don't even need to cut holes in the covering to reveal them... this is already done for you. Close examination of the rails show a small notch cut into the inside edge of one of them. This allows the servo wires to clear the rail. Very nice touch! Just drill pilot-holes for your servos and screw them in place. I used nice long aftermarket Allen head servo screws from Don's Hobby Shop. Used two packs of 20 in this plane. When installing the aileron pushrods, be very sure to set them up with aileron differential (1.25" up travel, .75" down travel, both sides). This is required to get a good flying airplane. As mentioned above, I used MK 3mm hardware, including the largest size horns which are 1" tall from base to start of thread. The thickness of the ailerons required special 3mm X 35mm bolts, but the result was worth it! If you are going to put pin-striping on the underside of the wing, now is the time to do it. The manual says there is no need to glue the wing together when using engines in the recommended range. When the two wing halves are put together, they form a 1/2"x3/4" plywood dowel that fits into a similarly strong hole in the fuselage. Then you screw down the back of wing with steel bolts into blind nuts in the fuselage. This keeps the wing on the plane, and the wing halves together. Even with larger than recommended engines, if there is going to be a failure, it won't be because the wing wasn't glued together.

The most challenging part of the assembly, with possible exception of the engine installation, is the landing gear and wheel pants. It's not hard, just different. Remember that the pants are designed to be "soft mounted" using rubber pads, both inside the wheel pant against the axel and at the pant's connection point to the wing. The only change I would make to the manual is that you should trial-fit the gear-wire (no wheels) with the pant onto the wing before you apply the rubber pad inside. To work the best, the axle must line up to the center of the pads. It seems normal for the pants to not sit flush with the wing, as a gap on both sides allows the gear to flex side-to-side quite a bit without breaking fiberglass. Don't try to bend the sides flush with the wing, or you will likely crack them. The gear-wire is very large gauge, nearly 1/4" diameter, and it is braced from behind. Remember to grind flat spots on the axles for the collar set-screws (one collar on each side of each wheel).

The included 5" wheels are of dense foam, and the hubs are aluminum. Very light weight, only 5.5 ounces for the pair. That is about the same as just ONE wheel from most makers. First problem I had with them was they tended to bind on the gear-wire. When you tightened the two-part hub, it usually deforms the hole for the axle and can cause it to bind. If there is even the slightest hint of binding, especially when pushing hard on them like the airplane will on landing, do yourself a favor and drill them out. Maybe drill them out anyway, just to be sure... slop in the wheel-to-axle is better than binding. I used a 1/4" bit, which worked very well. I also used some high-grade oil designed for bushings. Works great for metal-to-metal, non-ballbearing surfaces (there is special oil for bearings too... the R/C Car and Heli guys have cool stuff that work great on planes). The other problem I had with the wheels was during an unintentional high-speed touch-and-go, and when making a hard turn while still having quite a bit of speed after landing. During these high-stress times, the hubs had some tendency to unscrew themselves. Use red locktite or maybe even J.B.Weld when assembling them. I don't know how long the wheel pants will last. They seem reasonably thick, except right at the wheel opening where they are quite thin. I'd recommend reinforcing as much of them as you can reach with some additional fiber before installing the gear.

Fuselage

The Fuselage section of the manual begins with engine installation of either a glow engine (Saito 180) or a gas engine (Zenoah G-23). The included mount is of high quality and very similar to what Hanger-9 calls their "Ultra Mount". It will handle all your glow engine needs, as well as some of the gasoline choices. (I've seen gasoline engines as large as a BME 50cc on one of these mounts). Engine installation is complicated a little by the lack of a traditional engine-mounting-box. You bolt the mount directly to the firewall, which is the whole front of the model. The engine must also be installed inverted, because the placement of the cooling tunnel. An addendum to the manual indicates this mount is a replacement for the one originally designed for this model, which was found to be lacking. The addendum gives directions on drilling new bottom holes for the new mount... as these two are in the wrong location. One thing you will notice right away is the amount of down-thrust and right-thrust that are built into the firewall.

If you are using a glow engine, you can use the included 16oz fuel tank. It is already plumbed and nearly installed. All you have to do is add some foam-rubber to it and glue in the support. If you are using gas, you will need to come up with something else as the provided tank is not compatible and can not be made so, nor is the Styrofoam that is used as a tank support. I'm using a Sullivan 16oz Boat Tank with their Gasoline Conversion Kit, which I like very much. Wide and long, but flat and thin. Two would fit piggybacked if a person wanted to add a smoke system. One nice thing about gas engines is the ability to move the tank just about anywhere in the model and the carb will still draw fuel. I like moving the tank back to the Center of Gravity (C.G.), or as close as I can get it. I decided to put the tank's fuel-dot in a scale location up on top of the fuse ahead of the cockpit. To drill a hole through one of the stringers, I added some additional 1/4" basswood sticks on both sides. I used Aerotrend EasyFlex large-size (1/8" ID) fuel tubing. It's great stuff, stays flexible even in contact with gasoline. Regular Tygon gets stiff in a hurry. I plumbed it 3-line, one for the clunk/carb, one for venting, and one for filling. I put a Dubro The Final Filter on the clunk line to trap anything from the tank. I also have one on the end of my fueling setup. As you work on the inside of the fuse, you realize while the inside space is absolutely cavernous, access to it is limited. It is somewhat difficult to get to anything behind the cockpit or the space forward of the wing-dowel-hole to the firewall. Much of this is caused by the huge contact area of the wing-saddle. Still pretty easy to work on compared to smaller models.

Once you have installed your throttle servo, the manual has you work on the cowl next. First is to modify the dummy radial for your specific engine. Your engine needs baffling to get proper cooling in this huge cowl, and the dummy radial is designed to do just that. Hold the dummy up to your engine, and cut away just enough to get air flowing to the engine's cooling fins. You don't need any additional holes with the recommended engines, as the dummy does allow some air to flow around it, even in the places you don't cut. It only fits flush with inside of the cowl at the dummy cylinders, where you glue it. Next is to install the dummy radial into the cowl. The manual recommends centering the radial in the cowl, then adjust the angle of the cowl on the fuselage to make the engine come out the hole. To me this seemed like it would detract from the good looks, so I chose to instead center the cowl exactly on the fuselage, and move the dummy radial around so the engine comes out the hole. It doesn't make any difference... just personal preference.

The cowl mounts with four hardwood blocks that are already pre-attached to the firewall. There really is a lot of leeway in placement of the engine and cowl. The cowl is long enough to handle anywhere from approximately 5.5" to 7.5" from the firewall to the engine's thrust-plate. I added 1/2" spacers to the mount to get the RCS140's carb out away from the firewall nearly 3/4" to let it breath, which brought the thrust-plate out to ~6" from the firewall. I then installed the cowl as far back as I could, maximizing the amount of prop-shaft sticking out of the cowl. I figured with a cowl this big, 10" inside diameter, moving the prop out a full inch in front of the cowl would help the airflow around it. I don't know if it really made any difference. The manual gives a great suggestion on drilling the holes in the cowl. They have you put some tape on the model, starting from the mounting blocks, back about 5". You then draw a line down the tape from the center of the mounting block with a ruler. You then measure 3" from the center of the block back along the line and make a mark. When you put the cowl on, the tape and its marked line are visible. Measure from your mark back along the line 3" and drill your hole. Worked great for me, and I'll be using the technique on other models! I do suggest you add some reinforcement to the cowl at the drilled holes. Mine is starting to crack in a few places... even with the 6-32 nylon screws into tapped holes that are holding it on.

Final Assembly

We now move into what the manual calls "Final Assembly". First step is to install the horizontal stabilizer. This step is the most critical that it be done correctly, if you want a good flying model. You will notice that you don't even have to cut the covering from the stab, this is done for you. A good thing too, because this is a place that comes back to bite a lot of modelers. You want to make sure the stabilizer is perfectly aligned with the wing. Visual inspection is the order of the day here, and a table you can put the model on will keep you from crawling around on the floor. Sand the fuselage a tiny bit if any adjustment is needed. Also be sure to measure the stab to the wingtips and stab-ends to center of the firewall to insure the stabilizer is sitting square. Make alignment marks to help you get the stab back into position once you add the glue. Use a good 30 minute epoxy here... and re-check the alignment about half-way through the curing to insure it hasn't moved.

The vertical fin is next and is easy to install. It is an interesting keyed affair that slides down into a keystone-shaped slot at the back of the fuselage. Test fit it to the fuse. Draw around the forward fin extension and cut away the covering (leave an 1/8th inch border inside the line) to give this part of the fin a better bite. 30-minute epoxy here too. Once the epoxy has set, you can install the tail-wheel bracket to the bottom of the fuse.

Now is a good time to install the Rudder and Elevator servos. This should go pretty quickly once you have chosen how to arrange them. As mentioned earlier, a Pull-Pull arrangement on the Rudder may prevent needing to add lead to the nose using a light engine. It is also the way the full-scale was designed. Once installed, adjust the control travel. DO NOT, under any circumstances, put more than the recommended amount of Elevator travel. 5/8" both directions is more than enough... and any additional throw may result in a difficult to fly model. The recommended throw for the Rudder is a good starting point, and will allow the model to do some questionably-scale maneuvers, such as knife-edge. No knife-edge-loops with this model though!

Install your receiver and its battery and switch. I put the switch and an LED voltage-meter in the cockpit floor, in front of the pilot. A little hard to reach there, but out of sight. There are laser-cut holes in the instrument panel where it looks like you could possibly install a switch of some sort, but then you'd have to cut into the decal. Speaking of the decal, I'm terrible with decals. Especially when there isn't easy access to their mounting locations. I used a trick to make it easier. Instead of putting the decal directly on the plywood inside the model, I put it on some 1/16" balsa sheeting. I trimmed the balsa from around the outside of the decal, then installed the whole thing into the cockpit. That was easy! Now install the windshield and its trim tape. I put a 1/4-scale "1930's Pilot" from MGA in the cockpit. He has a great scarf that I figured would look cool in the air. Problem is, the white scarf is basically invisible against the white fuselage when flying. Oh well. The Wing struts are easy to install and really make a difference in how this plane looks. They are not however needed for flight. I ended up needing to remove the dowels from the struts and replacing them with something longer, as they had a tendency to come out in flight. Couldn't find dowels the same size, but some hard plastic lollypop sticks from the craft section of Walmart are working perfectly. Made them 1/2" long, and a bit longer wouldn't hurt.

You're pretty much done now! Balance the airplane to the recommended 4.5" from the leading edge of the wing. Check lateral (side-to-side) balance as well. Double-check your control throws before your first flight.

Flight Report

First flight occurred on a warm summer day in the middle of August. Temperature was 90F and winds were 10-15mph, but out of the south directly down the runway. Not the best conditions to test-fly a new model, but not a bad day. First item on the agenda was to pre-flight the aircraft. My friend and instructor Carl Johnson did the preflight check, with my assistance. Long time club member Troy Hamm was also present and gave us a hand.

Fueling of the gasoline/oil mix, which is Pennzoil air-cooled 2-cycle oil at a 35:1 ratio (not even half way through the first gallon of break-in fuel yet), is accomplished with the help of a Slimline M1 Gas fueling system. A great device! Being tired of sore arms after a day of flipping the propeller on my P-47, I decided while it was great that I could hand start it... I'd go ahead and use my Sullivan Dynatron starter instead. The Dynatron has no problem turning the engine over at a good clip, and while something more to carry to the field, it saves me from tennis elbow (or is that gas-engine-elbow?). I run it with a 12v lawn-tractor battery from Walmart, which has a built-in handle for easier carrying. Up-side to maintaining a battery and dragging it to the field is I now have a starter that would start every plane that wanted to fly at our field for the whole day, and still have plenty of juice to run field-chargers.

Next item was to range-check. First part of that was to establish a baseline range with the engine off and the antenna collapsed as much as is possible with the frequency-number flags. I watched the airplane, with Troy supervising, and Carl took the transmitter and started walking down the runway away from us. When he reached the end of the runway, about 300' away from the airplane and still no glitches, we considered it to have plenty of range. Carl came back and we then started the engine so we could check for interference. Important to do with any engine, but absolutely vital with a spark-ignition. With the engine idling, Carl started walking back down the runway. When he got to the end with no interference, he ran the engine up to full. Still no glitches. With the engine running full-throttle, Carl walked back up the runway to the other end. No problem, even with Carl's body between the transmitter and receiver. Based on Troy's suggestion, we even tried pointing the model directly at the transmitter, still 300' away with its antenna collapsed. This put the spark-plug and ignition system between the receiver antenna and the transmitter. Still no problems. This is the same experience I had with the RCS140 in my P-47. The Hitec 3600 plain FM/PPM receiver performed without a hitch. Having exhausted every reasonable test we could think of, we proceeded to the next step.

After refueling and restarting the engine, it was time to check the model's ground-handling. We fly from a rather new grass field that is still quite rough in places. We see a lot of people bring new models, often trainers, out to the field with 2" tires or sometimes even smaller. They more often than not will have problems and when they upgrade to larger tires, they see a significant improvement in ground handling. So, we were not too worried about the GBY and its 5" wheels. However, grass runways and wheelpants have a natural predator/prey relationship, sort of like trees and balsa, and you never know how they will get along until you find out. With the RCS140 idling at a still-new slightly high setting of 2500rpm, the model will sit pretty much still in the grass, but a gust of wind or a small blip on the throttle will start the GBY rolling slowly. Once the engine has a few more flights on it, I'll feel more comfortable with a lower idle.

With the large tires, and upgraded tailwheel, the GBY tracked very well on the ground. At very slow speeds, mine has some slight tendency to pull to the right and a little left rudder is needed. However, when the throttle is advanced a little and the torque of the gasoline engine increases and the weight on the tailwheel lessens, the model tracks straight. The rudder is centered, so a small adjustment of the tailwheel is probably in order. Some models I've seen hate turning in one direction or the other. Not this one, it seems to turn equally well in both directions. As a bigger airplane, it does take more room than a 40-size to turn. Little blips on the throttle increase the effectiveness of the rudder and helps swing the tail around. The GBY's nice wide stance, around 24" between the wheels, provides a very stable platform during taxiing. No tendency at all to tip over and scrape a wingtip, even during hard turns. Unlike my P-47, which needed extra elevator throws to keep the tail firmly planted on the ground, the GBY will taxi without any up elevator being applied at all. It has no tendency to nose-over, as long as the wheels don't bind on their axels. Having said this, I still need to keep the elevator in the up position just to keep in the habit of doing it. I will be returning to other taildraggers that are not so forgiving and there's no reason to practice bad habits.

Having found no good reason not to, it was time for the first flight! My knees, which had been knocking during the taxi test, were now steady. Easy for me to do... I wasn't going to be flying the airplane! I had already talked Carl into being the test-pilot, and I would be manning the camera. As sick as this sounds, I wanted video in case the engine had problems, like on my P-47, so that I would have some evidence to send to RCS... along with the remains. My RCS140 is a little cold natured, and takes a minute or two of warm-up before it is happy. Carl taxied down to the end of the runway, took a couple deep breaths to steady his nerves, and slowly advanced the throttle. As the model picked up speed, a little right rudder compensated for some pull to the left, completely normal for a big taildragger. Didn't take long for the tail to come up, and a second or two later, with a touch of up-elevator, she was airborne!

Climbout was very sure and strong. The RCS140 has no trouble providing enough power for nearly effortless takeoffs. Coming around the first and second turn, we noticed the model slowed down quite a bit... but regained speed within a couple seconds of leveling the wings. Just starting the downwind leg, I thought I heard the engine miss. But it was just Carl messing with the throttle. The new timing sensor seems to have made all the difference and the RCS140 performed nearly flawlessly. Still rich, especially on the low side. On the downwind leg, a little bit of up elevator trim and a little bit of right aileron trim, and she was flying hands off at ~300' of altitude. Coming around the back leg, Carl mentioned that it flew "heavy"... most any kind of turn or maneuver that generated any extra g-forces slowed the plane noticeably. As it flew past, part of the reason for this slowdown was heard... all the wind rushing past the big cowl and wheelpants. A lot of drag is being generated by these and it was having a more noticeable effect than one might normally expect from a 15 pound airplane. Carl took several laps, including one at low throttle to test the slow-flight abilities of the model. It handles the slow flight with ease, but don't let it get too slow, or the nose will drop. We have not noticed any hint of tip-stalling, both wing halves seem to stall equally, and doesn't take very long to recover.

Not wanting to push our luck too far, Carl throttled back and setup for a landing attempt. We had heard the model slows down very quickly with power removed, so we left some in until over the threshold. Too much, and the model floated right on past us. Back on the throttle sputtered and spit (come on baby!), but it cleared out the excess gas and came up to speed for a go-around. This time Carl brought it back to idle, which was still set at ~2500rpm, much earlier. Back a couple hundred feet from the threshold. That helped and he was able to set the model down before much more than half of the runway had slipped by. It didn't take long to slow down once on the ground... and he got it turned around and taxing back toward us. We both breathed a huge sigh of relief! After taking a break, we came back to refuel and get ready for flight number two. While I was refueling, I noticed the tailwheel was missing! Looking back at the pictures and movie clips, it seems we lost it during the taxi test but never realized it! I then decided that we would push our luck too far to try flight #2 today, so I started packing up. Carl went out and walked up and down the runway looking for my missing favorite tailwheel. As luck would have it, he found it down in the extra rough section of our runway. He never did find the wheel collar, despite urging from us to keep looking. (grin) I took the model home, double checked every possible bolt, nut, and screw (everything else was in order) and looked forward to the next opportunity to fly it.

Second flight occurred four days later. Still taking it easy, but starting to try more things. A very easy to fly airplane. Rolls were fairly axial. Tight loops were possible and very pretty, but the model ran out of steam very quickly if you tried to make them bigger. Stall-turns, or Hammerheads, poop out at about a 100'... just barely enough to do them at all. Even at full throttle, coming out a shallow dive, the model was not very fast either. I estimate its speed at 55mph. Faster than the really slow WW1 and similar airplanes, but much slower than your average sport plane. My overweight Contender with a .61FX would fly circles around it. It became apparent that if I wanted to do anything but the basic racetrack pattern at a leisurely pace, a bigger engine would be in order. As the number of flights grew, so did the maneuvers we tried. Much to our surprise, the model will knife-edge! Looses altitude very slowly (with the 16x8 prop and factory rudder throws), but is quite easy to handle. Also does a very nice "Show Pass", which is basically half of a knife-edge, rolled ~45 degrees to the spectators, and held in place with the rudder and elevator. Also to our surprise, the model exhibited basically no roll-coupling with the rudder. When you apply rudder, no aileron input is necessary to correct. The model flies well inverted too, with just the slightest pressure on the down-elevator stick to maintain level flight. Snap-rolls, and other advanced high-stress maneuvers, are probably better left to the airplanes designed for them. The GBY will snap roll reasonably in one direction, but very ugly in the other.

By the end of two weeks we had 12 flights and just under two hours of actual flight time (I'm maintaining a flight log). At flight 17 and just over 2.5 hours, I switched to an APC 17x8, which the RCS140 is currently turning at ~7800rpm. This made quite a bit of difference. If programs like ThrustHP are to be trusted, it should have slowed the model down by more than 6mph, which would have been noticeable. In reality, the model seemed a couple miles per hour faster with the bigger prop, even though it was turning 800rpm less than the 16x8. While the vertical did not improve, the model doesn't seem to slow down as much in turns and other maneuvers and take-off speed is obtained sooner. It may even slow down a little better on landing. We attribute this difference to the large diameter cowl. It must be penalizing the 16x8, which only has 3" of cowl clearance all around. The only problem I've had with the 17x8 is it requires some adjustment of the carb (high side was too lean). Your choice of engines is going to depend on what kind of performance you are looking for from this airplane, and what kind of fuel you like using. If the flight described in this review sounds like plenty of performance, then engines in the smaller end of my recommended range are going to be good bets. If you are looking for something more, then the larger engines become options. One nice thing about gasoline engines is their good fuel economy. Even at full throttle for the entire flight, we were seeing 15 minute flights come back with a few minutes of fuel left in the 16oz tank. Combine this with cheap prices for gasoline (even with the oil), and you have a very economical airplane to fly.

All in all, I am extremely happy with my purchase. It isn't perfect, see nit-picking above, but nothing is. I think I'll keep it... despite a couple of open offers to buy it from me (sorry Carl and Dan!). As of the writing of this review, two months after first-flight, the model has flown 22 times and over 3.5 hours. It received lots of praise and questions at the 2002 R/C Air Command MDA Benefit Airshow, in Taylor Missouri, where it made 6 flights totaling 70 minutes. I told everyone that asked, and a few that didn't, that this was an ARF from Pacific Aeromodels... and that I loved it! Seemed like nearly everybody stopped and looked it over at some point during the weekend. Most people with cameras seem to walk down the flight line of a show like this, and even if there are more than 200 planes present, will only take a few pictures. This model was photographed about as much as any airplane present. I even overheard a few comments that they had voted for the GBY for "Best of Show". All this and easy and fun to fly? Pacific Aeromodels has a winner for sure!

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