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TOP FLITE FOCKE WULF FW 190D-9 Also see Part II Adding Scale Details and Part III Fiberglassing and Painting. SPECIFICATIONS RCM PROTOTYPE SUMMARY
Editor's Note: Occasionally a model comes along that requires more time and effort to perform an in-depth review, and therefore takes considerable time to complete the project. Such was the case with the Top Flite Gold Edition FW 190D-9. When the reviewer first contacted us and explained that he wanted to perform a review that was "much more in-depth" than our normal format, we were a bit hesitant. However, he then explained that he wanted to take a production kit and make a few modifications and add the details necessary to make it competitive for the Scale Master's competition. Well, that sounded very interesting! Normally we do not allow modifications to a kit that is being reviewed, but since these would be the various changes necessary to meet the requirements for scale competition, we decided to give it a try. In addition to the review, he also suggested doing several articles on how to perform some of the modifications he used to make the model more competitive. So here it is; this review will be Part 1 of a 3-part article on preparing the Top Flite FW 190D-9 for scale competition. We sincerely hope that you will find it interesting, informative, and enjoyable. History: The Focke Wulf FW 190 was a true engineering masterpiece of its time, it served with distinction from its inception in 1941 until the final days of the war. Originally, the FW 190 was produced with a BMW 801 radial engine, the radial-engine powered version is the "A/F/G/S" model or "short nose" 190. The only reason the FW 190 was initially allowed to be produced is because it used a radial engine, virtually all of the Daimler Benz 600 series engines were allotted for Messerschmitt 109 and 110 aircraft. If the Focke Wulf had been designed to use the Daimler Benz engine, it would never have been produced. Because of a need for better performance at high altitudes, the FW 190A was re-equipped with the Jumo 213 series engine. Again, the Jumo 213 was chosen because the Daimler Benz engine was produced primarily for the Bf 109. It is interesting to note that the Jumo 213 was used in bomber aircraft not high performance fighters. Because the Jumo 213 is an inverted inline V-12 engine as opposed the BMW 801 radial design, fitting the Jumo 213 to the FW 190A airframe caused the appearance of the Focke Wulf fighter to change significantly. The nose of the aircraft was much longer, and in order to maintain the correct C.G., an extension plug was added between the tail section and the fuselage. These design changes give the FW 190D version a stretched look when compared to the FW 190A. The Focke Wulf FW 190D-9 "long nose Dora" became operational in the summer of 1944 and was universally acclaimed as the best fighter available to the Luftwaffe at that time, and is generally considered Germany's best mass-produced piston engine fighter aircraft of WWII. Approximately 700 FW 190D-9's were produced and served on western and eastern fronts in a variety of roles. Why Build The Dora? If the FW 190D-9 is looked at purely as an aircraft design and not a warbird, the layout is very similar to that of R/C pattern aircraft. The long nose moment provides easy balancing, ample wing area can support the weight of a detailed model and still keep the aircraft reasonably easy to fly. A long tail moment makes for a very effective horizontal stabilizer, rudder, and elevator controls. Focke Wulf FW 190D-9's are great flying models. Although the FW 190D-9 is not as well known as the short nose "A" version, if you do a little digging you can find a great deal of information on the aircraft. Colorful paint schemes and additional equipment (such as drop tanks, bombs, and rockets) are plentiful for the D-9. One of the most difficult decisions in building a Dora is choosing one aircraft to replicate over another. When I first heard that Top Flite was going to produce an FW 190D-9, I was very excited. Top Flite Gold Edition models have a reputation for engineering excellence and quality. When the kit became available I put my shop in order and got ready to put one together. I downloaded the instruction manual from the Top Flite Web site and read it several times to become familiar with the kit; I appreciated being able to review the manual while waiting for the kit to arrive, it allowed me to think about construction techniques and make appropriate notes so I was ready to start building when the kit arrived.
Construction: I followed the exceptional instruction manual and built all of the components in sequence. Great Planes Pro Wood Glue, Pro Epoxy, and Pro CA were used exclusively for the entire airframe construction. Using the lead shot bags recommended by Top Flite proved to be very useful. These bags are great for everything from holding sheeting in place to keeping the plans sheets unrolled. Horizontal Stabilizer And Elevators:During the construction of the horizontal stabilizer, the ply center plate was drilled with a 1/2" brad point bit in several spots to remove some of the material while retaining its strength. This may seem extreme, but I was concerned that tail weight was going to be my biggest problem with a detailed model, so I attempted to keep as much weight out of the tail as possible. An experienced modeler once told me, "mind the grams and you'll take care of the ounces." Extension covers were added to the trailing edge of the horizontal stabilizer using 1/64" ply. The ply covers are used to cover the stabilizer-elevator hinge gap and to give the model better scale appearance. The elevators were built open framed opposed to the fully sheeted method suggested by Top Flite. This was done for scale appearance as well as weight reduction. The elevator halves were tied together with a 1/4" birch dowel, sanded, and prepped with Coverite Balsarite. After covering the joined elevators with white Super Coverite iron-on fabric, Great Planes Pivot Point medium hinges were used to attach the elevators to the horizontal stabilizer. By connecting the elevator halves with the birch joiner, it was possible to attach the elevator control rod between the elevator halves and conceal the linkage by running it down the center of the fuselage. Attaching the elevators to the stabilizer at this point is a deviation from the building method suggested by Top Flite, but is necessary because of the need to connect the elevator control rod before adding the vertical fin. See Photo #1.
Vertical Fin and Rudder: The vertical fin was built as instructed by the manual. 1/64" ply covers were added to the fin trailing edge as done with the stabilizer. The rudder outline is larger chordwise than scale; I modified the drawing on the plans to reflect a more accurate outline. I built the rudder using the construction techniques described in the manual but added additional ribs and placed them in positions dictated by my 3-view drawing. The rudder was lightened by removing most of the material from between the ribs. After sanding the rudder to shape, the rudder frame was prepped with Balsarite and covered with white Super Coverite. See Photo #2.
Fuselage: Framing up the fuselage was very enjoyable. Each of the die-cut parts is well engineered and fit perfectly. The ply fuselage formers and fuel tank box create a light, yet very rigid, forward assembly. When assembled, the ply fuel tank box also doubles to set the correct degree of right thrust for the firewall. Many of the ply and balsa fuselage parts interlock, allowing for much of the fuselage frame to be assembled and positioned before gluing. My kit had a bad piece of die-cut balsa sheet containing several of the small rear fuselage formers. Instead of waiting for a replacement sheet to arrive from Top Flite, I removed the parts from the sheet and glued them back together using thin CA. See Photo #3.
This was my first experience sheeting a fuselage with 1/16" balsa. I love the idea of 1/16" sheet for the horizontal stabilizer and fin those areas are relatively flat and need to be kept as light as possible. I ran into a couple problems sheeting the fuselage that I directly relate to using thin 1/16" sheeting. The Focke Wulf has several areas that are difficult to sheet. Parts of the fuselage that required bending the sheeting around sharp compound curves don't seem to do well with the 1/16" sheeting. In these difficult areas, the sheeting between the stringers and formers tends to "cave in" somewhat. Balsa filler was used in the depressed areas to get the airframe as smooth as possible. Top Flite placed the tail wheel in the scale location on the fuselage and that was helpful in eliminating any major modifications but the set-up was changed to improve its scale appearance. A short steering tiller was made to keep the tail wheel linkage inside of the fuselage, the tiller connects directly to the rudder/tail wheel servo. A Williams Bros. 1.5" smooth contour tail wheel was installed and the tail wheel assembly built up to replicate the full-sized tail wheel yoke. After detailing the tail wheel assembly, the ply mounting plate is permanently installed in the fuselage. Balsa blocks were carved and hollowed, then glued in place around the tail wheel assembly. See Photo #4.
After sanding the fuselage I sat back and looked it over. I really like the treatment that Top Flite has given the tail. The tail section looks outstanding; the extension plug looks good, the fin is beautiful and the horizontal stabilizer has a nice looking symmetrical airfoil. The ABS cowling supplied with the kit is too small in diameter for the fuselage, and the scale outline of the cowl is not very accurate, so I decided to make my own fiberglass cowl. A small opening was cut into the front recessed area of the cowl directly in line with the engine cylinder. Ducting was made from .010" tin sheet to channel the incoming air flow over the engine cylinder and muffler. An additional opening was cut in the cowl around the engine cylinder head. The combination of the air inlet, ducting, and cylinder head opening provides plenty of airflow to prevent the engine from overheating. See Photo #5.
An O.S. .91FX 2-stroke glow engine was chosen to power the model. The .91FX is a bit larger than the suggested engine displacement; a larger engine was selected because I expected the finished weight of the model to be outside of the manufacturer's maximum projected weight due to the additional scale details being added to the kit. Because of the additional displacement of the .91FX, a larger 16 oz. fuel tank was installed for extra fuel capacity. The factory muffler for the .91FX will never work for a serious scale model and third party muffler choices are limited for the .91FX. I used a Slimline muffler designed for the Super Tigre .90 and adapted it for use with the O.S. .91 FX. The Slimline muffler is very compact and works fine for cowled scale models; however, it is rather loud, so muffler baffles made from brass tubing were used to quiet the engine down. See Photo #6.
I replaced the ABS fuselage machine gun cover with a custom-made part that has a better scale appearance. The replacement gun hood is removable and covers the receiver on/off switch, charge jack, retract filler valve, retract servo, and air control valve. Custom-made cast resin exhaust headers were made to replace the vacu-formed exhaust provided with the kit. See Photo #7.
Wing: The wing went together very well and was a pleasure to build. Building instructions were clear and the built-in wing jig made for super straight wing halves with built-in washout. The wing is sheeted with 1/16" balsa, the same as the rest of the model. None of the problems occurred with sheeting the wing that were present when sheeting the fuselage. The wing was built according to plan with a couple exceptions. The ailerons are scratch-built to the same outline as the plan, but otherwise use a method of construction that more accurately represents the full scale aircraft's ailerons. After building the ailerons, they were sanded to shape and prepped with Coverite Balsarite before being covered with white Super Coverite fabric. The aileron linkage was moved to the top of the wing in the scale location to improve scale appearance. Robart Horny Hinge Point hinges were used for the aileron control horns, Great Planes Pivot Point medium hinges were used for the remaining aileron hinges. A 1/64" ply cover was applied to the top of the wing to cover the wing-aileron hinge gap similar to the covers used for the rudder and elevators. See Photos #8 and #9.
The flaps were built per the instruction manual with changes being the concealed control horn and enclosed linkage. A small 1/8" aircraft-grade ply control horn was glued to the top of the flap even with the leading edge. The control linkage runs through the wing trailing edge and connects to the flap without being exposed. Hitec metal geared mini servos were chosen for controlling the flaps because of their low weight and high output torque. Great Planes Pivot Point medium hinges were used for connecting the flaps to the wing. Retracts: Spring Air's new #709 retract bodies and their new matching oleo struts designed for the Top Flite FW 190D-9 were selected for use with the model. These retracts have the needed 74 degrees angle for the correct strut appearance that is so important to the look of an FW 190 model. An Ultra Precision air control valve (made specifically for Spring Air retracts) was used to control the retract system air flow. The control valve can be adjusted so the retracts have a very nice, slow retraction. Spring Air retracts are a bit different than other manufacturer's retracts in that the retract cylinder has an internal spring. Because of the spring, the gear will come down and lock if air pressure is lost. The days of belly landing your prized scale warbird because of a retract air leak are over! On the other hand, the spring does not let the retracts extend in a slow scale manner. The best you can achieve is to set the Ultra Precision control valve to slowly bleed off the retract cylinder pressure so that the gear will "fall" open with very little force as opposed to slamming open. I really like the Spring Air gear for the Top Flite FW 190D-9. These retracts are of high quality with great fit and no slop. See Photo #10.
Gear doors were made from ply and balsa and attached to the struts using scratch-built brackets. The construction manual states that gear doors need to be removed for flight. I did not find this necessary using the Spring Air gear and keep the gear doors on the model at all times. This is a huge plus as far as scale realism is concerned. Williams Bros. 3.75" Smooth Contour wheels were used for the main gear. Surface Finish: After the completion of the airframe, all of the hardware was removed from the model. The entire model was block-sanded using a stiff foam rubber block and 220 grit sandpaper, then block-sanded again with 320 grit sandpaper. After sanding, the model was blown off with low pressure compressed air and wiped down with a tack cloth to remove any residual balsa dust. CST 0.55 oz. fiberglass cloth was used with Pacer Z-Poxy finish resin to cover the airframe. The finish resin was allowed to cure for several days before sanding. A stiff foam rubber sanding block and 220 grit sandpaper was used to knock down the high spots on the newly glassed airframe. The model was cleaned and sanded again with the sanding block and 320 grit paper. Krylon sandable primer in the spray can was used for priming. The model was primed and sanded with 320 grit wet/dry sandpaper and water until the surfaces were smooth. Panel line tape was added to the model and then the airframe was re-sprayed with primer and sanded out with 400 grit wet/dry sandpaper. When the panel lines were complete, hatches were applied and the airframe was riveted. See Photo #11.
Paint: Water-based latex house paint was used for the "blue-green" base color. The latex was sprayed on with an automotive touch-up spray gun and allowed to set up for a couple hours before coming back and applying the Testors Model Masters enamel RLM 82 and RLM 83 greens. The camouflage was allowed to cure for a week before the markings were painted on. Model Masters enamels were again used for applying the markings. Frisket airbrush mask was used to create stencils for the national markings and high quality automotive masking tape was used to mask the fuselage defense bands and the large wing crosses. When the paint and weathering was complete, Perfect Paint's dead flat clear was used to fuelproof the model. See Photo #12.
Radio Gear: An Airtronics Radiant 6-channel computer radio is used to guide the model. Single Airtronics 94322 ball bearing servos were used for the ailerons, rudder and elevator. An Airtronics 94102 servo was used for the throttle, two Hitec 225MG metal geared mini servos were used for the flaps, and a Tower Hobbies System 3000 mini servo was used to activate the air control valve. The area inside of the fuselage for radio equipment is rather small and cramped. Using the area under the fuselage gun hood for the retract servo/control valve, the retract filler valve, the charging jack, and on/off switch helped keep the radio installation organized and sanitary. See Photos #13 & 14.
Pre-Flight Preparation: The O.S. .91FX was run-in on a test stand before being installed in the model. All radio gear was checked for direction and throws, the pull-pull rudder control system was adjusted as was the tailwheel control rod. The radio was set up for dual rates, with the high setting being set to Top Flite's recommended maximum throws. The Ultra Precision air control valve was adjusted for the desired retraction speed and extension bleed-off rate. Toe-in for the main wheels was set a few degrees inward by sight. The model was balanced as described in the instruction manual and it came out right on the money! No nose weight was required for static balancing with the gear down. Watching the tail weight really paid off to keep additional dead weight out of the nose! See Photo #15.
Flight Test: The model was brought out on a cool morning with a slight crosswind. The radio was range-tested and everything was found to be in good order so it was time for action! Jerry Orme, an expert pilot at our field, performed the duty as initial test pilot. Jerry eased into the throttle and started the Focke Wulf moving forward. As the Dora reached our position at runway center, the tail was up in the air and it was tracking like it was on rails, another few feet and the 190 broke ground. The model required a couple clicks of down trim and a click of left to achieve level flight. After retracting the gear another click of down was required. The engine was running very rich and went through a tank of fuel in a very short time. While Jerry was setting up for the landing pattern, the engine ran out of fuel! Not able to make the runway, Jerry turned the model in to face us and proceeded to dive for airspeed; when the model was approximately 15' from the ground, he rounded out the descent and flared the model for a perfect landing! See Photo #16.
We brought the model back in and looked everything over. Everything seemed fine so we decided to give it another go. The rudder was desensitized by taking out some of the control throw, the model was refueled and ready to go again. The take-off was perfect and the model climbed out beautifully with the long FW 190 gear folding up slowly as it climbed away from us at a 10 degrees angle. The second flight was less eventful with Jerry bringing the 190 in gracefully with the flaps at 30 degrees and the throttle set a few clicks above idle. A perfect touchdown, a short roll-out, and it was over for the day. While in the pits, John Cole and I talked over the events and what could be done to improve the performance of the model. The change in pitch from the gear being up or down caused John to think that a few additional ounces in the nose could help reduce the required trim change. The following weekend I brought the 190D-9 back out with an additional 1.6 ounces of nose weight to see if the in-flight trim changes would be reduced. John agreed to fly the model while I took some pictures. He taxied the 190 out and proceeded to take off. Again, this model is rock solid on the ground! Tracks like it's on rails with little or no rudder required to maintain a straight heading. After getting the model in the air, John noted that the trim change needs had been reduced and now only a couple clicks of elevator change was required over the entire spectrum of gear up/gear down, flaps up/flaps down. The model performs flawlessly in the air and goes exactly where you point it. To land the model, simply line it up and decrease the throttle setting until you achieve the angle of descent you require, then land the plane using the throttle. On final approach, using 60 degrees of flap, only a few clicks of throttle is needed to keep the model in a gentle descent. The model will land so slowly that it will only roll about 40' before coming to a complete stop after touching down. The Top Flite FW 190D-9's flight performance is excellent!See Photos #17 & 18.
Conclusion: This was a very satisfying and enjoyable project. The wooden airframe engineering in this kit is excellent. I love the treatment the Top Flite engineers gave the tail. The FW 190 tail has a very unique appearance and they did well by it. I had one piece of die-cut balsa sheet that had split and was of poor quality. One of the turtle blocks was missing from the kit's inventory. Unfortunately, the plastic parts were not up to the standards set by the wooden portion of this kit, so I made my own parts rather than use the plastic parts supplied with the kit. Also see Part II Adding Scale Details and Part III Fiberglassing and Painting. Reprinted with permission.October, 2002 R/C Modeler Magazine Editor: Patricia Crews HOME |
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