RCU Review: Great Planes Little Toni

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    Contributed by: Michael Luvara | Published: March 2005 | Views: 97247 | email icon Email this Article | PDFpdf icon

    Review by: Michael Luvara
    Photos by: Chris & Michael Luvara

    Great Planes
    P.O. Box 9021
    Champaign, IL 61826

    Phone: 217-398-3630
    Fax: 217-398-0008

    • 4 Channel Radio with 5 servos, switch, battery and Y harness
    • Engine & propeller
    • Glue (CA and epoxy)
    • Foam Rubber
    • General shop tools (screw drivers, drill bits, tap, hobby knife, etc)

    Little Toni

    The Little Toni is known as one of the famous Formula 1 racers of the 1940's. Sleek, and slender, this little racer is a champion on looks and in the air. Better known as the Cosmic Wind, there were three variants – The Little Toni, Minnow and Ballerina. All with subtle differences, they retain the same general looks and sported similar color schemes (red/white, green/white,etc).

    Great Planes has brought this classic aircraft out in ARF form after many years of being unavailable on the R/C market from any R/C manufacturer. Most notable was the previous Bridi/Great Planes kit, which sported a fiberglass fuselage. At a 63" wingspan, the airplane is quarter scale, and consequently IMAA legal.

    Little Toni

    Stock Number: GPMA1320
    Wingspan: 63 in (1600mm)
    Wing Area: 775 sq in (50dm 2 )
    Weight: 7.25-8.25 lb (3290-3740g)
    Wing Loading: 21.5-24.5 oz/sq ft (65-75 g/dm 2 )
    Length: 56.5 in (1435mm)
    Engine Required: 2-stroke .61 cu in (10cc) or 4-stroke .91 cu in (15cc)
    Radio Required: 4-channel with 5 servos

    Opening the box, you will find an excellently packed kit, along with one of the highest quality ARF's on the market. I am constantly amazed at the workmanship in most of the ARF models today, especially when it comes to the paint and mask work involved with producing so many of these kits with such splendid paint jobs.

    Great Planes is known for their superb aircraft and instruction manuals. This aircraft is no exception. Accompanying the aircraft components is a 27-page manual, with excellent diagrams and photography of the construction process. Instead of duplicating the work they have presented in the manual, this review will drift from the norm and focus more on the flight characteristics and technical aspects of the model, along with what was found during construction. ARF construction is becoming fairly standardized these days and the exact steps need not be covered in their entirety.

    Included in the kit is a high quality fiberglass fuselage, cowling, and wheel pants. A built-up wing and horizontal stabilizer, covered in Monokote, are beautifully done, ready for the builder to glue in the hinges. The fuselage has an integral vertical fin and includes a Monokote covered rudder. The cowling is one piece and slides snugly over the fuselage. A painted aluminum landing gear is supplied, with all holes drilled and even countersunk where necessary. An excellent set of decals rounds out the kit contents. At first glance, there isn't much for the builder (assembler) to do.

    Kit and supplied accessories for review

    Cowling with pre-cut cooling slots


    Supplied with the review model was a Great Planes glue pack, which included 6 & 30 minute epoxy, mixing sticks, cups, and brushes. We were also supplied with a flight pack, consisting of four Hobbico CS-65 servos, a Futaba S3004 switch, Futaba 127DF receiver, and a 600mah battery pack.

    One of the first things done prior to construction was to obtain weights for each of the individual components and understand where the weight of the airframe would be coming from. More often than not, models exceed the manufacturer's weight claims. The break-down is as follows:

    Fuselage (with vertical fin and rudder): 1lb, 14oz (30oz)
    Cowling: 5.8oz
    Wing: 21oz
    Horizontal Stabilizer: 3oz
    Landing Gear: 3.8oz
    Wheel Pants: 3oz (1.5oz ea)
    Spinner + hardware: 4.4oz
    Engine: 21oz

    From the weights, it can be seen that the components weigh in at reasonable numbers. Noticeably light is the horizontal stab. The cowling and spinner are a little on the heavy side.

    Construction first began with the wings. The supplied hinges (CA glue type) were cut into the appropriate size (from the supplied large strip) and then inserted into the control surfaces. These hinges are more or less plastic with a mesh of fibers bonded to each side and resulting
    in material about 1/64” thick. Great Planes recommends drilling small holes into the center of the hinge slots so that the thin CA will wick into and penetrate the wood farther, resulting in a better hinge bond. After affixing the hinges with thin CA, it was time to prep for the joining of the wing. The wings are set up for two aileron servos (one per panel), which is a must for a plane of this nature. Already routed through each panel are pull strings for the servo wires. After ensuring the strings were routed out their respective pre-cut holes in the top of the wing, 30 minute Great Planes Pro epoxy was mixed up and applied to the wing joiner and mating surfaces. Once the two halves were pressed together, tape was applied to hold things in place while the proper dihedral was measured and the glue cured.

    Drilling glue "weep" holes for better penetration

    A look at the airfoil and wing construction

    Wing Joiner

    Checking wing dihedral

    Aileron Hatch bay, with pre-routed pull string

    Aileron servo and linkage

    The landing gear supplied with the model has pre-drilled mounting holes and is even painted to match the aircraft. One simply locates the supplied screws and bolts it onto the aircraft, with the application of Locktite on the screws. Mounting of the wheel pants and wheels is rather straightforward. With the exception of the wheel axles, nothing requires cutting or drilling. Simply bolt it on and you are done.

    Pre-painted landing gear

    Marking cut for wheel axle

    Landing gear installed

    Supplied with the review model was a SuperTigre 90 engine, slightly above the displacement recommendation for the kit. The .90 is physically the same size as the .60 and .75, so fitting it in the cowling was not a problem. This engine is the newer model SuperTigre, clearly denoted by the “ China ” lettering on the back of the muffler. Comparing it to the previous Italian counterparts, the engine casting is clean and well made. On the surface, it looks every bit like the original

    SuperTigre .90

    Stock Number:
    Displacement: 0.90 cu in (14.73 cc)
    Bore: 1.083 in (27.5 mm)
    Stroke: 0.976 in (24.8 mm)
    RPM: 2,500-16,000
    Output: 2.5 bhp @ 14,800 rpm
    Weight: 20.66 oz (589 g)
    Includes: muffler; exh. stack; glow plug
    Requires: mount (HAYG2085); fuel; prop
    Recommended Props: 12x8, 13x6 (w/inc. muffler)

    SuperTigre 90

    SuperTigre 90 mounted on airframe

    Mounting of the engine is straightforward. First, one locates the bolt pattern template provided in the manual (page 27) and then uses this to drill holes for the engine mount. Referencing the pattern to the firewall is easy as there are centerlines molded into the fiberglass fuselage. The manual provides a distance for mounting the engine (5-5/16" from firewall to front of prop washer). There is no mention of thrust offset in the manual, so one assumes the engine is to be mounted perpendicular to the firewall, which has thrust offset already built in. The cowling is another guideline, with a special spacer included to jig it to the fuselage. The paint lines on the cowling match very well with the fuselage. Some cutting will be necessary on the cowling so that the engine fits. This includes openings for the high speed needle, cylinder head, and exhaust. The amount of cutting will vary with the engine used.

    View of servo tray, pre-installed formers and pushrod housings

    Top view of firewall. Note right thrust.

    Front view of firewall with cutout for fuel lines

    Mounting the wing is unbelievably painless. The dowels are already installed in the wing leading edge and holes for the wing bolts already drilled. Blind nuts are even installed in the fuselage. Simply locate the wing bolts, put the wing in the saddle, and bolt it on! A check of the wing-tail alignment showed it was well within reason.

    Removing overspray in horizontal stabilizer slot prior to gluing

    Affixing the stab is a very simple process. The horizontal tail simply slips into the cutout already in the fuselage. After roughing up the inside of the slot (removing paint overspray) to achieve a good bond, and removing the necessary covering on the stab, the unit was slipped in, trued, and glued in with thick CA. It is not necessarily possible to glue in the stab with epoxy, due to the fact that there is no way to get glue inserted inside. The stab has to slide in and hence, would make quite the mess if trying to be slid in with epoxy on it. Once dry, the elevators were connected to the stab and hinges affixed in place with thin CA. Next up was mounting the rudder and its integral tail wheel. The tailwheel assembly is simply a pre-bent piece of wire that is glued into a slot in the rudder. Using thin CA, the rudder was glued in place with the supplied hinges.

    The exceptional quality of the kit hardware was evident when it came time to install the pushrods. Great quality pushrods, along with sturdy control horns and clevises, make up the major connections. In the fuselage, pushrod housings for the elevator and rudder were already installed, saving much time. A housing for the receiver antenna is also integrated in the fuselage, giving a nice touch. In only two instances did we deviate from the recommended control linkage hookup. On the elevator pushrods, it was suggested to connect the two parallel elevator pushrods together with wheel collars. Instead, we opted to wrap the two wires together with copper wire and solder for a sturdy bond. The throttle linkage even comes with its own laser cut pushrod supports. This was our second deviation, as a flexible cable was utilized for the throttle linkage. In no time, the servos were installed in their pre-cut slots and moving control surfaces.

    Servo installation. Note soldered elevator pushrods

    Tailwheel and control horn details

    Kit hardware and supplies

    Laser cut pushrod supports for throttle linkage. Nice touch!

    Wing number decal

    Applying decals

    Lastly, the kit's decals were applied to the aircraft. They come on one sheet and have to be cut before application. We cut them to size, sprayed some Windex on the area of application and then placed the decals in place. A squeegee was then utilized to work all of the fluid out from the underside of the decals. The result is a very clean application (no bubbles) and the chance to reposition them before fixing in place. The decals are of high quality and add a nice touch to the plane

    Total weight of model without fuel: 7.75 lbs (within listed weights!)


    Now that construction was complete, I couldn't wait to test fly this beauty. More often than not, it is reported in reviews that a model "was fast", "exhibited great stall characteristics" and "flew on rails". We used an RCATS telemetry system to measure some of the data from the test flights and give a better understanding of the model from a technical perspective.

    After checking the center of gravity and going over flight controls, we fired up the SuperTigre 90, spinning its 12x8 prop, and performed a radio range check of our Futaba radio equipment with the engine on. With slight adjustments, the engine was running well, and the only concern was some vibration. It was elected to flight test the airplane.

    Taxiing out onto the 520' runway at the SCCMAS ( www.sccmas.org ) field in Morgan Hill, CA, power was applied and the tail of the Little Toni quickly came up into the air. Ground tracking was very predictable and shortly thereafter the Little Toni was airborne. After climbing out to a safe altitude, the throttle was reduced to about one-half, and trim was applied to keep the Little Toni flying level. The throttle was later opened for a brief period this flight, in order to test the flight envelope and structural integrity, since the engine is over the recommended size. After a few minutes, it was time to bring the aircraft back in and check it over after the first flight. Landing is as would be expected. Without a headwind, the aircraft is difficult to slow down, due to its clean lines.

    Upon inspection of the aircraft after the first flight, it was found that the cowling screws were loose. No other items of concern were found. For the second flight, we re-fitted the spinner in hopes that it would eliminate the vibration being seen. The second flight was uneventful, except for the engine quitting suddenly, and resulting in an off field landing. After inspection, it was found that the supplied fuel line had developed an air leak where it connects to the carburetor. Further testing showed that while the supplied line stretches well, it does not like "compression" from tools such as forceps when pinching and thus contributed to our engine quitting. Because of the rough landing, we had to make some repairs and fly again another day. Further investigation of the spinner concluded that it was severely out of balance, possibly due to the backplate not being flat. This was causing excessive vibration. The aircraft was repaired and further flights were performed without the spinner nosecone installed.

    (Editors note: Great Planes has since made some changes to the spinner, and they have already been incorporated into production.)

    For the next several sorties, the aircraft was put through its paces. We tested stall characteristics, high speed dives (120 - 130 mph), aerobatics and whatever else the mind could think of. The aircraft fared very well throughout these tests. The short coupled airframe was found to snap in excessively tight turns if one is not on top of it. If this occurs, simply release the controls and let it build up speed. Nevertheless, the airplane has great flight characteristics, of which any sport modeler will enjoy.

    Originally, we had hoped for higher speeds out of this combination. The SuperTigre engine never really put out the horsepower that was expected of it, thus speeds were down compared to preliminary estimates. This appears to be due to the baffling in the stock muffler causing excessive restriction. One option is to change the muffler. However, this is a newer model supertigre, made in the Chinese factory. The engine has a good transition and overall power curve.

    While the Little Toni is a racer at heart, it is also quite aerobatic. Snap rolls are quick, yet it stops when one releases the sticks. Loops and rolls are quite typical and one should laterally balance the aircraft if they expect perfectly executed loops. Inverted flight requires a little down elevator, but nothing out of the norm.

    A summary of telemetry data collected during flights is shown below.

    Stall speed: 20mph IAS
    Takeoff speed: 25mph IAS
    Typical airspeed (level flight): 90-110mph IAS
    Max airspeed (dive): 131mph IAS
    Note: IAS represents Indicated Airspeed , via pitot-static probe pressure measurement. This is not “ground speed”
    Typical G's in normal flight: +4 to 6, -3