KYOSHO TRAINER 40 ARF Kyosho/Great Planes Model Dist.

Transcription

1 REVIEW KYOSHO TRAINER 40 ARF Product Review October 2000 R/C Modeler Vol No. 10 KYOSHO TRAINER 40 ARF Kyosho/Great Planes Model Dist. By Tim Smith SPECIFICATIONS Name KYOSHO TRAINER 40 Aircraft Type Trainer Mfg. By Kyosho/Great Planes Model Dist., 1610 Interstate Dr., Champaign, IL (800) , Mfg. Sug. Retail Price $ Available From Retail Outlets Wingspan 63 Inches Wing Chord 10.5 Inches Total Wing Area Sq. In. Fuselage Length 49.2 Inches Stabilizer Span 23-1/8 Inches Total Stab Area Sq. In. Mfg. Rec. Engine Range.32 to.46 Rec. Fuel Tank Size 8 Oz. (included) Rec. No. of Channels 4 Rec. Control Functions Rud., Elev., Throt., Ail. Basic Materials Used In Construction Fuselage Balsa & Ply Wing Balsa & Foam Tail Surfaces Balsa Building Instructions on Plan Sheets No Plan Sheets

2 Instruction Manual Yes (15 pages) Construction Photos Yes RCM PROTOTYPE Radio Used Futaba 9ZAV w/4 servos Engine Make & Disp. HP.40 Silver Star 10 x 6 APC Prop Tank Size Used 8 Oz. (included) Weight, Ready to Fly 80 Oz. (5 Lbs. 0 Oz.) Wing Loading 17.4 Oz./Sq. Ft. SUMMARY WE LIKED THE: Wing attachment options, pre-installed pushrod outer tubes, ease of assembly, pre-drilled engine mounts, and flight performance. WE DIDN'T LIKE THE: Control surface clevises, engine mount and nose wheel bearing mounting hardware. As an active R/C aircraft modeler with interests spanning pattern flying to primary flight instruction, I enthusiastically jumped at the opportunity to review this new entry into the R/C trainer marketplace. I consider it vital to continuously return energy to the hobby that has provided me with so much enjoyment and self-satisfaction. Experience has shown that one of the most painless methods for learning the ins and outs of our sport/hobby is to begin with an aircraft designed specifically for the purpose of primary training. I am pleased to report that the Kyosho Trainer 40 meets this need quite nicely. Kyosho has designed a high quality, high wing trainer aircraft utilizing a semi-symmetrical wing. The combination of traditional high wing configuration and a more aggressive wing allows the newly soloed R/C pilot to further enhance their flying skills and prepare for transitioning to higher performance sport-type aircraft. When you walk into your favorite hobby shop to get a firsthand look at this almost-ready-tofly model, one thing is certain: you will not miss the box. It measures 43-3/4" long x 16-

3 5/16" wide x 3-3/8" high and features a nearly full size photograph of the trainer, detailing its very bright yellow color scheme. The box contains lots of good pictures and information regarding the aircraft and its engine and radio requirements. Upon opening the box, you will be very impressed with the packaging technique Kyosho has implemented. All major components - the fuselage, the wings, the fin/rudder, and horizontal stab/elevator - are all bagged in plastic and packed with the perils of cross country shipping in mind. All accessory parts such as the engine mount, wing joiner, landing gear wires, etc., are contained in several separate plastic bags. Parts identification and inventory was very easy and revealed a very high quality ARF kit. The wings are balsa sheeted foam and are built straight and light. The fuselage is of conventional construction and uses aircraft plywood in all the necessary high stress locations. As with the wings, it is also straight and light. The vertical fin and horizontal stab, along with their control surfaces are also of conventional, built-up construction and, as before, are straight and light. All visible glue joints appear to be quite satisfactory. Everything you need to get this bird in the air is included in the box with the exception of the spinner (2" diameter suggested), engine, fuel filter, latex foam (for radio protection and fuel tank isolation), and the radio. Construction: When I begin construction of any new model, the first thing I do is sit down in a comfortable chair and read the construction manual. Now, I know this might be considered heresy in some circles, however, I have found that having full knowledge of how the model is designed allows more informed construction decisions as the project progresses. As I read the Kyosho Trainer 40's construction manual, several initial impressions formed in my mind. The manual appears very "busy" because it contains both Japanese and English directions. However, this does not detract from the completeness of the manual. Kyosho details what accessories you need to purchase, and what tools are required for assembly. This is very important information for the new R/C modeler. Parts for each step are identified at that step in the manual. One very important note: all measurements are provided in metric units. Great Planes to the rescue, however. Great Planes provides a supplemental instruction manual that follows the Kyosho manual step by step and provides

4 comments and outright changes as necessary. Included in the supplemental manual is a metric conversion chart that takes the terror out of metric to standard unit conversion. I found that my pre-read of the manuals allowed me to note what Kyosho steps needed to be modified via the supplemental instruction manual before I made any mistakes. The supplemental manual is very well written and easy to follow. After reading the manuals and then closely inspecting the parts, several more impressions formed. I found it very exciting that this kit offers an option that allows the builder to attach the finished wings to the fuselage with either the traditional rubber band technique or use wing hold-down bolts. I chose the latter. Pushrod outer tubes for the rudder and elevator are already installed in the fuselage. This is a timesaver in that you do not need to construct your elevator and rudder pushrods out of the traditional 1/4" sq. stock or dowels. The supplied music wire pushrods are pre-bent at one end with a "z" bend to accommodate the servo horn. The covering on the model was accurately applied with acceptable graphics registration across the hinge lines. My technique for building this model was very straightforward. I simply followed the stepby-step construction manual and its supplement. Although space constraints do not allow me to go into a high level of detail on each step, I will cover what I consider to be the most important items for the new modeler. As a side note, be sure you have a set of metric tools on hand for this project, as all supplied hardware is of the metric persuasion. Construction begins by joining the wings and installing the aileron servo. I found that the wing joiner went too far into each wing slot. I simply packed the wing slot with a few scraps of paper to ensure the joiner went in the proper distance. I found that 3/4 ounce of 30-minute Pacer Z-Poxy (3/8 ounce each of epoxy and hardener) was quite enough to cover the wing joiner and wing roots. While you are mixing up epoxy, I suggest you coat the engine compartment with 30-minute epoxy also. This will perform two very important functions: first you will positively fuelproof the engine compartment, and second you will seal the edges of the pre-applied covering all around the engine compartment. Before leaving the wing, be sure to drop some thin CA onto the pre-installed hinges. They are not glued in at the factory. Next comes installation of the engine mount and nose gear bearing, immediately followed by the installation of the fuel tank. A problem was uncovered during fuel tank installation. The fuel tank will not properly fit in the fuselage because the supplied engine mount screws and nuts protrude too far into the tank compartment. If the tank is installed without modifying the engine mount screws, the screws will certainly vibrate their way into the tank and cause a fuel leak. I solved this problem very quickly by substituting 6-32 blind nuts and cap screws cut to the proper length. The same problem exists with the nose gear bearing mounting screws. The nose gear bearing mounts on the firewall directly below the engine mount. The supplied screws were also too long and were replaced with 4-40 blind nuts and cap screws cut to the proper length. When installing the fuel tank, be sure to measure the tank outlet position to determine the tank's top and bottom. The top of the tank is approximately 5/8" from the top of the tank outlet. Be sure to pack the sides, top, and bottom of the fuel tank compartment with 1/2" latex foam for vibration isolation. This will help prevent fuel foaming and lean engine runs. Now comes the main landing gear. When mounting the main landing gear, I found that it was much easier to substitute the supplied bolts, nuts, and washers with #4 x 3/4" socket

5 head sheet metal screws. Use a 3/32" drill to drill the pilot holes into the landing gear hardwood mounting blocks. At this point in the construction, you must make your decision as to which wing mounting method you will use. As mentioned before, I chose to mount the wings using hold-down bolts instead of rubber bands. Exercising this option is a simple matter of gluing two dowel pins into the leading edge of the wing and installing two blind nuts into the wing hold-down blocks. I strongly suggest this approach, as it is much faster and easier to install the wing and results in a stronger attachment. Installing the vertical fin and horizontal stabilizer components is next. The instructions are very clear. Be sure to use adequate 30-minute epoxy and remove the film covering at the appropriate locations. The instructions are also very clear regarding what measurements are critical when you install these components. To ensure a straight airplane, you must pay careful attention to these measurements. As with the wings, be sure to glue in the elevator and rudder hinges with thin CA. The final steps in the construction of the model involve installation of the pushrods, control horns, the engine, and the radio system. The instructions are very clear, covering all these operations. A word of caution, however. The supplied hardware package, although very complete, contains several control linkage components that contain setscrews. Specifically, the elevator clevis, the rudder clevis, the throttle servo horn quick link, and the nose wheel steering servo control horn quick link all contain setscrews. In order to review the kit as faithfully as possible, I used the supplied hardware in all cases (except as noted above). Be sure to use some thread lock on all setscrews after you have determined the final positions of the clevises and quick links. This will hold the setscrews tight, but will allow future removal with normal hand tools. PIC 4 - The HP.40 Silver Star engine used in our review model. Engine: Randy Linsalato of RJL Industries, (800) , was kind enough to supply us with an

6 HP.40 Silver Star engine. The HP fit the supplied mount perfectly. The HP is of standard configuration and was mounted vertically, utilizing the supplied muffler and an APC 10 x 6 prop PIC 5 - There is ample room for any standard size radio equipment. Radio: I used my Futaba 9Z radio system for this aircraft. Certainly, this model does not require a radio of this complexity. Any good quality, current technology 4-channel radio system will provide satisfactory performance. The radio compartment of the Kyosho Trainer 40 contains ample room for three standard sized servos. I used three Futaba S3001 servos for the control surfaces (aileron, elevator, and rudder), and one S3003 servo for the throttle. All servos fit nicely in their respective mounting locations. The instructions suggest installing the battery pack under the fuel tank. There is adequate room and access to do so, however, the review aircraft turned out nose heavy, so I installed the battery pack immediately behind the fuel tank and the aircraft balanced within the C.G. range, without adding additional weight of any kind. When installing the nose wheel steering pushrod, install it on the inner most hole of the servo horn; otherwise, the nose wheel steering is way too sensitive. When you are connecting the clevises to the control horns and the pushrods to the servo horns, I suggest you start at mid positions. Remember, to increase control surface throw, move the clevises toward the control surface, and the pushrods away from the servo center post

7 Flying: Before even thinking about going to the field with any new aircraft, I made absolutely certain the C.G. and the manufacturer's control surface throws are set as specified in the instructions. For the Kyosho Trainer 40, the C.G. was located at 86mm aft of the leading edge as measured with the Great Planes C.G. Machine. This is within the 76mm to 89mm C.G. range specified by Great Planes in the supplemental instruction manual. Using a combination of mechanical means and computer radio magic, the control throws were set exactly as specified by Great Planes and verified by the Great Planes Accuthrow control surface deflection meter. Once the C.G. and control throws were verified, it was time to load up and head to the field. After locking out my frequency and performing a thorough range check, I fueled up the 8 oz. (approximate) tank and proceeded to start the engine. I prefer to use electric starters on all size engines, and my trusty Sullivan Hi Tork starter kicked off the HP.40 instantly. I spent a few minutes adjusting the high speed and low speed needle valves and the engine was idling beautifully with very smooth transition. I had run a tank of fuel through it on a test stand a week before. After refueling, I restarted the engine and taxied out for take-off. As with all first flights, one must always expect the unexpected. As I advanced the throttle on the HP, the engine came alive and the aircraft accelerated smoothly. Nose wheel response was overly sensitive and was noted for correction. About 100' down the runway, I eased back on the elevator and the aircraft smoothly rotated and climbed out. I found I needed to hold a slight amount of left aileron in order to maintain wings level. After takeoff, I performed a climbing right turn to gain altitude and performed several trim passes. Two clicks of left aileron and two clicks of up elevator were all that was required in order to achieve hands-off level flight. The unexpected did not occur. The next eight minutes were spent testing C.G., high and low speed characteristics, power-off stalls, and power-on stalls. The HP.40 is more than adequate power for this aircraft. Horizontal speed is plenty to get a new RCer's heart thumping, and the engine's reliability at mid range settings couple to make this an ideal aircraft/engine combination. The aircraft exhibits very stable flight characteristics at slow speed. Flying the aircraft at 1/3 throttle was very predictable and the factory control throws prevent inadvertent over control.

8 Power-off stalls were very docile. In fact, with the factory control throws, the aircraft never really stalls, it simply begins descending at a sink rate only slightly above a power-off glide. There was absolutely no tendency to tip-stall. I was impressed with how gentle the aircraft handled at slow and very slow speeds. At the other end of the spectrum, power-on stalls are more pronounced with the nose falling off more abruptly as a function of the climb angle. As with the power-off stalls, power-on stalls were very predictable with no tip-stall tendencies. Flight number one was completed with three touch-and-goes and one full stop landing. The Kyosho Trainer 40 is a very easy airplane to land. It does exhibit a slightly higher sink rate than a trainer with a flat bottom wing, however. I consider this to be a reasonable compromise given the wider performance envelope the semi-symmetrical wing provides. Flight number two was focused on the self-correction features of the aircraft's design and simulated dead-stick landings. I tested the self-correction features by placing the aircraft in unusual attitudes (similar to situations in which a newly soloed R/C pilot might find himself or herself) and, after reducing the throttle to idle, simply watched the aircraft. Here again we see the compromise of the semi-symmetrical wing. In a turning (i.e., overbanked) situation, the Kyosho Trainer 40 did, in fact, attempt to return to level flight (due primarily to the wing dihedral). However, pilot correction must come slightly sooner than if this were a flat bottom wing. In a nose low or nose dive situation, the aircraft essentially continues on its trajectory with no attempt at self-correction. This is a trait of sport-type aircraft, and must be well understood by the novice pilot. The plus is that it provides good transition training to the newly soloed R/C pilot. Simulated dead-stick landings with the Kyosho Trainer 40 were very predictable. As expected, the aircraft does exhibit a slightly higher sink rate than an equivalent flat bottom wing design. This sink rate, however, is well within the skill set of a typical fledgling R/C flier. Conclusion: I like this airplane and feel it will meet the training needs of the entry-level R/C pilot. The kit is of high quality and requires only novice building skills. I found the instructions, along with the supplemental manual, to be very clear and unambiguous. Those few construction issues I found and noted have been presented here to aid in your successful completion of the model. The aircraft flies very predictably. With the C.G. and control throws set to the factory specified settings, a brand new, inexperienced R/C flier should have no trouble whatsoever learning to fly this model. Of course, this presupposes he or she also has a competent flight instructor. The combination of the Kyosho Trainer 40 with its semisymmetrical wing and the HP.40 Silver Star engine will provide an ideal learning environment for the student, and then an excellent transition platform for the newly soloed R/C pilot who is looking for the higher performance second airplane. All Contents Copyright R/C Modeler Corporation. All Rights Reserved.