This item is discontinued.

GREAT PLANES GIANT EXTRA 330L
PRODUCT REVIEW
by Mark Shapiro

Aircraft Type Aerobatic Sport Scale
Mfg. By Great Planes Model Mfg., P.O. Box 9021, Urbana, IL 61826-9021. www.greatplanes.com
Mfg. Sug. Retail Price $649.99
Available From Retail Outlets
Wingspan100.5 Inches
Wing Chord 14.25 Inches (Avg.)
Total Wing Area 1670 Sq. In.
Fuselage Length 86.25 Inches
Stabilizer Span 40.25 Inches
Total Stab Area 416.5 Sq. In.
Mfg. Rec. Engine Range 2.8-5.25 2-Stroke, 50 cc-85 cc Gasoline
Rec. Fuel Tank Size 24 Oz.
Rec. No. of Channels 4+
Rec. Control Functions Rud., Elev., Throt., Ail., Ignition Kill Switch for gasoline engine

Basic Materials Used In Construction
Fuselage Balsa & Ply
Wing Balsa & Ply
Tail Surfaces Balsa & Ply
Building Instructions on Plan Sheets No
Instruction Manual Yes (52 pages)
Construction Photos Yes

RCM PROTOTYPE
Radio Used Futaba 8 UAPS, PCM Computer Radio 10 Servos
Engine Make & Disp. Zenoah Z445 (6T-74), 74 cc; 6 h.p. 4.5 c.i.
Tank Size/Battery Used 24 Oz./two 1,800 mAh 6 volt
Weight, Ready to Fly 400 Oz. (25 Lbs., 0 Oz.)
Wing Loading 34.5 Oz./Sq. Ft.

SUMMARY
WE LIKED THE:Excellent material quality, clarity of plans, building manual, kit engineering, outstanding flight characteristics, and performance.
WE DIDN'T LIKE THE: Lack of photos in manual for certain phases of construction, insufficient clearance for servo in horizontal stab.

Great Planes Model Manufacturing Company has built a well deserved reputation for designing, engineering, and kitting outstanding model aircraft. In recent years, Great Planes/Top Flite has entered the market of Giant Scale with a bang. Giant Scale versions of the P-51 Mustang, F4U Corsair, P-47 Thunderbolt, and Stinson Reliant have been widely successful; and for good reason. With the introduction of its new Giant Scale Extra 330L, however, Great Planes has taken its "Giant Scale" efforts to new heights.

Our review kit arrived in two large boxes. Box one contained virtually all of the balsa and plywood needed to complete the 330L. It measured 49"L x 11"W x 6-1/2"D. In addition, a prebent, predrilled heavy duty aluminum landing gear was also included, along with an aluminum wing and horizontal stab tube. As an added bonus, a well written, well illustrated, handbook entitled: A Look At Aerobatics was included. The booklet is well thought out, and gives a detailed explanation on how to perform various aerobatic maneuvers. Aside from some miscellaneous nuts, bolts, and screws, no other hardware was included with the kit.

Box two measured a hefty 33"L x 15"W x 12"D, and contained a few laser-cut ply wing rib sheets that just could not be squeezed into box one, a huge clear canopy, a pair of fiberglass wheel pants, and a huge fiberglass cowl. All of these items, excluding the wood pieces, were carefully wrapped in plastic bags to assure their arrival in an undamaged condition.

As has become a Great Planes' trademark, the instruction manual was simply outstanding. The 51-page manual includes numerous photographs, "expert tips," and clear and concise written instructions. With the exception of a few photographs that either did not depict clearly what they were intended to show, or the absence of photographs which would have assisted the builder, we rate this manual among the best we've seen. In addition to building instructions, the manual also gives advice on take-offs, landings, propeller selection and engine choices. It also offers suggestions for non-computer radio set-up.

As for the building plans, the kit comes with four huge sheets of beautifully drawn plans. While two of the sheets were sufficient to depict wing, stab, and fin construction, the fuselage is so large that the remaining two sheets were needed to fully set out the fuselage construction. The two fuselage plan sheets are taped together at a specified pre-marked location. Since the fuselage is built directly over these plans, I needed to extend my building table to nearly eight feet in order to accommodate our 330L. No question, this is one very large bird.

Construction:

Construction begins with assembly of the tail feathers. The designers, Mike and Ann Marie Cross, have designed into the 330L many of the features one might find in an aircraft destined for top level competition. As such, a plug-in wing tube design is used for the wings, and for the horizontal stabilizer as well.

The horizontal stabilizer is the first structure to be built. Both the horizontal stabilizer, as well as the wing, utilize a novel approach in their engineering. For each, full length notched webs are used to interlock with the notched ribs of the respective structures. Usually, ribs are glued directly to hardwood spars and followed up with individual pieces of balsa being glued between ribs to act as sheer webs. Spars continue to be used on the 330L, of course, but this new system adds full length solid webs to the equation, making for an extremely rigid wing and horizontal stabilizer.

The horizontal stabilizer frames up very quickly. After laying out the three full length webs and gluing the ribs in place, the phenolic stab tube socket is carefully guided through the laser-cut holes present in S1 through S4. Nowhere is the precision of laser cutting more apparent than it is with the phenolic tube holes made in both the stabilizer ribs and corresponding wing ribs.

The stabilizer ribs extend out past the trailing edge web, and ultimately become the elevator ribs. After sheeting the entire structure with 3/32" balsa, the ribs are separated from the stabilizer with a razor saw. The elevator is completed by gluing balsa leading edges to both the elevator and its counterbalance.

Each elevator servo is mounted underneath its respective stabilizer half. While the plans provide an effective system for constructing an elevator tray, its placement does not permit enough clearance between the top stabilizer sheeting and the servo end closest to the stabilizer trailing edge. The solution to this problem is to add a 1/8" piece of scrap ply to the servo tray at its trailing edge. Finally, I added a servo lead conduit between the servo opening and the root stabilizer rib. The second stabilizer half and elevator are constructed exactly as the first.

The fin and rudder are next and are even simpler to assemble than the horizontal stabilizer and elevators. The fin and rudder, unlike the stabilizer and elevators, are built separately. The fin is constructed first, and is begun by gluing the aft ends of the die-cut fin ribs to the fin post. Next, the fronts of the ribs are rested on the fin leading edge, which acts as a temporary jig in order to assure proper alignment. The front of the fin ribs are then secured utilizing yet another full length leading edge web, and glued in place using thin CA. Just like that, you are ready to sheet the fin.

As with the fin sheeting, rudder sheeting is fashioned by edge gluing 3/32" balsa sheets together, and trimming these sheets to a specified shape. The fin sheet designated as the right side is then secured over the plans, and die-cut ribs are glued to the sheet using "hash" marks drawn on the plans as a placement reference. The left side rudder sheeting is then fitted in place over the ribs and glued in. Now, 3/8" x 1-5/8" balsa blocks are glued to specified locations on one side of the leading edge to act as hinge blocks, and the whole thing glued to the leading edge of the rudder. Finally, the rudder counterbalance is glued in place and its leading edged sanded to shape.

Wings:

The wings are built upside down, directly over the plans, one panel at a time. Like the fin, the wings are constructed with the aid of balsa jigs in order to assure a warp-free finished product. After pinning the top hardwood spar into position over the plans, the full length main web is positioned on top of the spar, and the ribs are slid onto it. Both the main web (as well as the others) and the ribs are notched, resulting in an excellent glue joint. The notched leading and trailing edge webs are then placed over the ribs and into position. At this point, the leading and trailing edge jigs are slid under the panel and into place, and are pinned to the building surface.

From here, the phenolic wing tube socket is carefully guided through the laser-cut holes in ribs W1 through W6. Special attention is now focused on assuring that the entire structure is firmly in contact with the wing jigs, and that the wing jigs are firmly in contact with the building surface. Once you are certain that all is well, use thin CA to glue all of the joints.

The remainder of the wing construction continues to be very straightforward. Glue in the remaining hardwood spar, attach the balsa leading edge, attach the basswood trailing edge spars, and carefully glue the leading edge and center sheeting into place.

The next step is to install the wing tube bolt block into place, and drill a 7/64" hole through the block and into the wing tube socket, located directly under the block. When completed, the wing is turned over and the other side is sheeted like the first.

At this point, a decision must be made as to what the final servo configuration will be. The plans provide instruction for both single or dual aileron servo construction. We chose to use a dual aileron servo set-up, and strongly recommend that all owners of the 330L do the same. While the manual states that a single servo with a capability of at least 100 oz. of torque is acceptable, we feel strongly that a dual set-up not only provides redundancy from a safety standpoint, but also aids greatly in reducing the possibility of aileron flutter.

As with the stabilizer, the wing ribs extend out past the wing's trailing edge, and form the framing for the ailerons. After sheeting and separating the aileron from the wing panel, a balsa leading edge is glued onto the aileron, and cap strips are glued onto the unsheeted portions of the wing ribs. The entire process is repeated for the left wing panel.

Fuselage:

As with most Giant Scale Extras we have seen, the core of the fuselage is built around a "fuselage center box," and later built up using ply formers to achieve the appropriate fuselage shape. Our review model employs this type of engineering.

Before fuselage construction can begin, however, you must have the engine which you intend to use. This is because in order to determine the correct lengths of each fuselage center box side, the builder must take a measurement of his engine's length from the back of its mounting plate, to the back of its thrust washer. Using this measurement, a formula is provided which permits the builder to determine the correct length for each fuselage center box side. Later in the construction, the firewall is glued to the inside of each side with its face positioned flush with each side's box.

When positioning the engine on the firewall itself, another measurement is provided with specifies the correct location for engine placement. While there were very few errors noted in the manual, we believe that the "up/down" measurement given should be increased by 1/4". Using the measurement given of 2-11/16" down from the top of the firewall, results in the spinner backplate being elevated exactly 1/4" above the cowl. A fellow modeler building the 330L experienced the same problem but simply used a smaller spinner rather than re-do his firewall. If you intend to use the recommended 5" spinner, you'll need to follow our lead.

After determining the fuselage center box side lengths and trimming them as needed, the right side is pinned down directly over the plans. The right ply after center box side is also pinned in position over the plans and 1/4" hard balsa sticks are then cut to size and placed into position, forming the bridge-truss configuration.

As it is absolutely critical that the left fuselage center box side is identical to the right, the left side is built directly over the right side. We placed Great Planes Plans Protector between the two sides so as not to unintentionally glue them together. Time must be taken here to assure that the left side is an absolute mirror image of the right. When the left side is completed, both sides are placed upright and side by side, and ply formers glued in-between. Once all of the formers are glued in, additional 1/4" sticks are used to complete the trussing on both the top and bottom of the fuselage. The ply landing gear support plate and tail gear mount are secured to their respective ends and just like that, the heart of the fuselage is established.

At this point, it is time to mount the wing and tail into the fuselage. A 6" segment of the phenolic wing tube socket is positioned in place through the laser-cut holes in both the left and right center box sides. Then the 36" aluminum wing tube is slid through and centered. The right wing is then positioned onto the tube and a 7/64" hole is drilled through the previously drilled hole in the wing bolt block, down through the top of the aluminum tube. The hole is then tapped using a 6-32 tap, and the wing is bolted onto the tube. The left wing is then slid over the tube but no drilling is done yet. First, a careful measurement is taken from the center of the aft most point of the fuselage, to each tip. Make adjustments, if needed, until both measured distances are equal. When the measurements are the same, glue the wing tube socket in place using medium CA. After the CA cures, drill and tap a hole through left wing and aluminum tube side, as done with the right.

To install the horizontal stabilizer tube, insert the tube socket and tube through the aft center box sides, assuring that the tube is parallel to the wings. Make adjustments as needed, and glue the stabilizer tube socket in place. The stabilizers themselves are attached to the aluminum tube in the same manner as done with the wings.

As mentioned above, ply formers are placed in position around the fuselage center box sides and sheeted using 3/32" balsa. A front deck and turtledeck are then fashioned, and finally the fin is epoxied in place.

Fuselage construction comes to a close with the cutting and final positioning of the canopy. Once again, take your time here and be patient. We found this aspect of construction perhaps the single most time consuming area of the entire kit. This is because in order to get it right, you must take your time and plan out the way you want this "centerpiece" of your model to look.

In addition to putting a 1/3 scale DGA sport pilot in our cockpit, we were also fortunate to have two instrument panels custom made for us (one each for the pilot and passenger), by Mr. Larry Maurer of SAC Products. These panels are absolute works of art and are now available for the Great Planes Extra 330L for $75.00 per set. Orders should be forwarded to: SAC Products, 1420 Sophi Way, Kissimmee, Florida 34744, or call (407) 348-0663. These panels are beautiful and add so much to the final look of your model. Special thanks again to Larry and his staff.

This is a big model ... eight high-torque servos used on the flight control surfaces; two on each aileron, two on the rudder, and one on each half of the elevator.

Covering:

Our review model was covered using Top Flite MonoKote. We viewed literally hundreds of photographs of full-scale Extras to get some creative ideas for our review model's trim scheme. Finally we decided on using insignia blue, dark red and white, and employed Top Flite LusterKote paints on the cowl, wheel pants, and aluminum landing gear.

Covering the 330L is no different than covering any other model; the only obvious difference is the amount of area to be covered. Since we like to have as few seams between the color as possible, it was necessary to use a 25 ft. roll of white MonoKote in order to cover the length of the fuselage. Six foot rolls were adequate for seamless covering of the wings and tail feathers. In addition to the tools we generally use, Top Flite's trim sealing tool was tried for the first time. It's hard to believe that we never utilized this sealer in the past. It provided great assistance in sealing those hard to reach places, and proved necessary in and around the narrow areas of the wing openings and cowl mounting ridge. Add this one to your pegboard.

To power the Giant Extra, a Zenoah Z445 (74 cc) Twin was selected.

Engine:

Our choice to power the 330L was the Zenoah Z-445 twin cylinder gasoline engine. This engine was chosen based on its long standing reputation for power and reliability. Additionally, if replacement parts are required, our past experience with Zenoah engines has been that such parts are readily available and easy to install/replace. Recently, Zenoah has renamed this engine the GT-74, reflecting its more respectable 75 cc's of displacement.

The GT-74 has many interesting features. Of particular interest, the GT-74 employs the use of a spring starter to aid in ignition. Since this engine uses a magneto system, the spring starter makes actual engine ignition almost effortless. Right out of the box, our engine started and maintained a steady idle. As recommended, a 24 oz. Sullivan fuel tank was used, utilizing the included gasoline-compatible fuel lines.

As equally impressive as the 74's performance, is its economic value. First, the actual cost of the engine is very competitive with other engines in its class. Add to this the inclusion of twin stock mufflers, built-in engine mount, accompanying hardware, tools, and no need for an aftermarket, weight/cost enhancing ignition system, and the choice is clear!

There is no question that the completed Extra 330L represents not only a significant investment in time, but hard earned money, as well. Possessing the level of piloting skills I have, I have enough to worry about in returning my aircraft to earth in one piece. The last thing I want to concern myself with is the reliability of the power plant. As gratuitous as it may sound, Zenoah engines in general, and the GT-74 in particular, make any such concerns a non-issue.

Larry Maurer of SAC Products made the beautiful instrument panels.

Radio:

To guide our review model, we called on our trusty Futaba 8UAPS PCM 8-channel computer radio. While the instruction manual provides some guidance for radio set-up using a non-computer radio, our experience with radio set-up for models such as the 330L, is that there really is no adequate substitution for a quality computer radio. The 8UAPS allows for easy fine tuning of both twin aileron and twin elevator servo set-up and adjustments. Additionally, the 8UAPS permits customized mixing configurations between various control surfaces. While non-computer radios will permit a platform for basic set-up, they restrict the user's ability to realize the aircraft's full potential.

We decided to outfit our review model with twin servos for each aileron, two servos for the rudder, one for each elevator half, one for the throttle, and one for an on-board kill switch; mandatory for gasoline engines. All but one of the servos are Hitec HS-615 metal gear servos and produce 110 in./oz. of torque. A standard servo was used to activate the Great Planes on-board kill switch.

A Futaba 1024 PCM 7-channel receiver was installed and the entire package is powered by dual JR 1,800 mAh 6 volt batteries. As the HS-615's are rated for 6 volt battery application, a voltage regulator was neither necessary nor included in the final set-up.

Flying:

Our review model sat around for almost two months before good weather and a Sunday afternoon coincided. Finally, the waiting was over and the much anticipated event was going to take place.

My trusted test pilot, John Rodriguez, was waiting or me when I arrived at the field. Since he was going to have the honors, I was glad to see that he had been warming up on one of his smaller, "twitchier" birds. After assembling the wings and stabilizer, we fueled up and did our range check with the transmitter antenna collapsed. After firing up our Zenoah, we did a second radio check with the engine running through its full range, and all systems still remained go.

Finally, the 330L was taxied onto the 400 ft. paved runway, where we taxied around for a few more minutes to acquaint ourselves with its ground handling. As expected, the Ohio RC Products tail wheel steered our aircraft effortlessly and with precision.

We taxied the 330L to the very end of the runway, pointed her into the wind, and smoothly advanced the throttle. The Extra tracked remarkably straight down the runway with only minimal rudder correction needed to compensate for engine torque. The tail came up on its own and with just a touch of up elevator, our 330L was airborne. Much of our apprehension with the first flight lie in the unpredictability of the trim. To our utter delight, virtually no corrections were required.

After reaching a safe altitude, John pulled back on the throttle and we just flew our Extra in circles for a while until we both caught our breath. We took off and continued to fly our plane on the low rate settings. After several circuits, however, we concluded that the recommended low rate setting for the ailerons were a bit too low for our liking. The performance at this setting was "mushy" and made the plane look a little sloppy in its turns. Also, we noticed that our plane was slightly tail heavy. This became apparent on our landing approach, as just before touchdown, the wings began to rock back and forth in a prelude to a stall. Luckily, John was able to recover and land the 330L in one piece.

After thoroughly inspecting every inch of the aircraft after our first flight, we re-positioned our on-board batteries and increased the low rate settings just slightly. On our second and subsequent flights, the corrected C.G. and increased low rate aileron throw, made our flights far more enjoyable. It should be noted that our tail heavy condition was due to our error in balancing the model, and not to an incorrect C.G. determination.

On high rates, I can only describe the 330L's performance in one word: Incredible! This plane really is capable of every maneuver in the book, and then some. The high rates recommended are geared toward 3-D aerobatic flying. While our own limitations prevented us from performing many of the 3-D maneuvers illustrated in the included aerobatics handbook, the usual rolls, loops, inverted passes, Cuban eights, knife-edge flight and others were effortlessly executed at these settings.

For landings, we switched back to low rates. Landings were smooth and predictable. One caveat, this plane must be flown under power all the way to the runway. For each of our flights, the throttle was not chopped until the aircraft was actually over the runway. Our review model settled down very nicely, and bled off speed very quickly. Short runways should be very compatible with this model. There were no bad tendencies exhibited on our review model.

Conclusion:

We love the Great Planes Giant Extra 330L! This is one outstanding model aircraft and we cannot endorse it highly enough. Mike and Ann Marie Cross have outdone themselves in the design and development of the 330L, and we congratulate them on their effort.

Be advised that while this model goes together as easily as most Great Planes models do, this is not a beginner's kit! Sheer physical size and power alone, require that only experienced modelers take on this project. Additionally, while the kit cost itself is not at all unreasonable, persons contemplating the purchase of this model should be aware that Giant Scale also means a giant investment when you add up the engine, high torque servos, hardware, etc. While we believe this model could be completed for less, cutting too many corners would be at the expense of realizing this remarkable model's full potential.

This one is an absolute must have for anyone looking for a top performing Giant Scale sport/aerobatic model.