|Wing Area:||17.4 dm2 (270 sq in)|
|Weight:||80 oz. (2.48kg)|
|Length:||1090 mm (43")|
|Wing Loading:||42 oz/sq. ft.|
|Transmitter:||Airtronics RD6000 Sport|
|Receiver:||Hitec Micro 555|
|Battery:||Sanyo RC3000mah NiCad and 3300mah NiMH|
|Motor:||Kontronik FUN500-19 brushless|
|ESC:||Kontronik BEAT 50-6-18|
|Fan:||Schübeler DS-51-DIA 3-ph|
|US Distributor:||Special Order via Hobby Lobby|
My Father was a fighter pilot in the U.S. Navy from 1956 to 1966 and growing up in that environment has instilled in me the love of aircraft and flying. I have had the desire for a number of years to build a flying model of each of the aircraft my father flew while in the Navy – the SNJ-6 Texan, T-33A Shooting Star, T-28B Trojan, F9F Panther, F2H-3 Banshee, F4D Skyray and the F8U Crusader.
The introductory advertisements for the Aeronaut F9F Panther EDF caught my eye and would allow me to build a large sport scale model of the type aircraft that my father flew in 1956 while in advanced flight training at NAS Kingsville, Texas. Thankfully my father took a number of photos of the Panthers and Shooting Stars he flew while at Kingsville. The Panthers on the ramp were a varied bunch and as you can see from the photos, there is quite a variety of color schemes to choose from.
A great resource, and one that has covered the Aeronaut Panther with various threads, is the Jet Discussion Forum that is part of The E Zone. Additionally, I referenced the F9F Panther/Cougar In Action by Squadron/Signal Publications and Scale Aircraft Modeling, February 1985, Volume 7, Number 5.
Upon opening the sturdy box, I found a well packaged, beautifully made, molded fiberglass airframe consisting of the fuselage, wing panels, vertical tail section and the horizontal stabilizer. Along with these parts, the Panther kit included molded plastic parts for the cockpit and canopy, plastic nose caps for the tip tanks, die cut wood parts for the servo mounts and rear fuselage bulkhead and a bag of miscellaneous parts. Added to this were the decal sheets and a German text instruction manual. The manual included a listing of the kit contents and a drawing showing the location of the kit parts throughout the completed model. (The manufacturer indicates that normally internationally shipped kits would include the English manual, which is available for download on their site as well.)
The quality of the molded fiberglass parts that make up the Panther’s airframe is top notch, with the parts being molded in a deep blue color. The lay up of the parts is commendably light and reflects a design effort to keep the completed model low in weight for improved flying performance. The wings are complete panels and have a carbon fiber tube/balsa spar with a portion of the carbon fiber tube being used as the joiner to the fuselage. The primary bulkheads in the center of the fuselage are already installed as are the two inlet ducts though these were not glued to the inlet lips which are part of the fuselage itself.
The instructions noted that the Panther was designed to be used with Aeronaut’s own Turbo-Fan 1000 ducted fan unit. This ducted fan unit is not one I have seen available here in the U.S., so I chose instead to use the excellent Schlübeler DS-51-DIA 3-ph ducted fan unit to motivate the Panther.
The Panther’s high level of pre-fabrication allowed for a quick build of the model and the instructions did a good job of going through the steps to end up with a completed model. Consequently I’ll skip over the general assembly and touch on a few items that I think need to be noted and a few I changed from those detailed in the instructions.
When assembling the wings, I needed to glue on the plastic nose cap onto each of the tip tanks – these being already molded integrally with the wings themselves. The nose caps initially did not fit very well and needed a bit of trimming and sanding to get a reasonable and smooth fit. Prior to gluing the nose caps on, I did a visual check of the interior seam line of the tip tanks to make sure that I was satisfied they would stay tight if the tanks are flexed or squeezed a bit. I had one tip tank that split at the outboard seam as I was holding it, while sanding the nose cap/tip tank seam. I needed to take care when handling the tip tanks during construction.
I used JR 341 servos for driving the Panther’s ailerons. I needed to cut open the wing skins to install the servos. The root rib of each wing panel has a couple of access holes already cut in it and through these I could see and determine the location of the spar in the wing. I chose to use masking tape on the wing surface to mark the location of the spar so that I didn’t cut or nick it while cutting the wing skin for the servo installation. The servos, when initially installed, protruded above the wing skin toward the trailing edge. To keep them flush with the surface, I had to sand the ply servo plates supplied with the kit to a wedge shape. This worked well and once sanded, the ply plates were glued into place with a bit of epoxy.
The Panther was designed to be bungee launched. The tow-hook (actually launch pin would be a better description) installation for bungee launches as detailed in the instructions struck me as being a potential problem. Due to the side load placed on it while under tension, the pin could hang up in the tube, which in turn would likely cause the loss of the model. I chose instead to go the simple route and installed a small external tow-hook under the forward fuselage.
The vertical fin was attached to the fuselage by a locating pin on the front portion that matched up with the bulkhead in the fuselage. I placed a short piece of brass tubing in the bulkhead so that there would not be wood-to-wood contact susceptible to wear and tear. The vertical fin was then secured in place at the rear of the fuselage with an M3 size screw. This made for a more secure installation of the vertical fin.
There is a “C” shaped ply bulkhead (Part 5) that needed to be glued into the rear fuselage to both stiffen it and to also center the exhaust tube in the fuselage. It was important that I fit the fan unit and the rear duct in the fuselage prior to tacking the ply bulkhead in place. I also fit the vertical fin in place and made sure that it fit the fuselage neatly. Once I was satisfied with the fit, I could then complete the installation by permanently gluing the ply bulkhead in place.
The cockpit and canopy parts are molded ABS plastic and needed to be trimmed to fit the canopy opening on the fuselage. I needed to take my time in trimming the canopy to fit to be rewarded with a clean, near seamless fit. The canopy was secured on the forward edge by a locating pin and at the aft edge by a spring loaded brass canopy lock. I did not use the canopy lock but instead used a Radio Shack rare earth Neodymium magnet (Part # 64-1895)for a cleaner appearing installation.
The Panther’s inlet ducts were pre-installed during the manufacturing of the fuselage assembly due to their shape and how they fit into the bulkheads pre-installed in the fuselage. The leading edge of the inlet ducts were not attached to the fuselage at the inlet lips and needed to be glued into place. To secure the ducts to the inlet lips/fuselage, I first taped them in placed from inside the duct and made sure they were properly aligned. When satisfied with their alignment, I tacked the inlets in place with a small amount of CA. Once the CA had cured, I then made up a small batch of Pacer Z-Poxy Finishing Resin and mixed in micro-balloons to make a slurry. From within the fuselage, I filled the space behind the inlet lips and the duct so that there was a solid filler between the two when cured. This made for a solid installation which in turn allowed me to sand the seam between the inlet lip and the duct for a smooth surface, important for proper airflow to the ducted fan unit. I also used some of this slurry to join the ducts inside the forward fuselage where they came together on the fuselage centerline. This stiffened both ducts and helped keep them from possibly buzzing or collapsing on themselves when the fan is pulling air in.
At the rear end of the installed ducts (on the centerline), there was no cut out to accept the spinner on the fan unit which protrudes forward of the fan housing. This fiberglass needed to be trimmed to allow sufficient clearance for the spinner for whatever fan unit is mounted.
The hinge line for the elevators were quite stiff and took a lot of effort on the servo’s part to move the surfaces. I ended up scoring the upper stabilizer skin along the hinge line to free up the elevators. I’ll need to keep an eye on this to make sure that no cracks occur along the hinge line. Should this happen, I’ll tape the hinge line to secure it.
The Panther instructions had the builder securing the battery pack for the ducted fan directly to the forward fuselage floor. I chose to make a tray to accept the battery pack which would allow me to adjust the location of the pack, to allow for adjustment for the center of gravity. I also made a shelf that fit above the tray to mount the receiver and receiver battery pack. This worked well and made for a simple and clean layout.
When mounting the DS-51-DIA 3-ph fan unit, I needed to fabricate mounting lugs which were then glued directly to the fan housing. I sanded the gloss off the fan housing surface in the areas where the mounting lugs went and then glued them in place with Pacer Z-Poxy Finishing Resin. The Panther’s rear fuselage bulkhead has three threaded units already installed which accept M3 screws. The lower mounting point (at the 6 o’clock position) was essentially inaccessible when the fan unit and exhaust tube were in place. I chose not to set a mounting lug for this lower mounting as I simply could not reach it. The DS-51-DIA 3-ph fan housing consequently is held in place only by the upper two locations (10 and 2 o’clock positions). I have not had any problems with this set up and the fan and motor are well secured to the bulkhead.
As noted before, the F9F Panther is designed to accept Aeronaut’s own Turbo-Fan 1000 ducted fan unit. This ducted fan unit is not readily available in the U.S. and thankfully the Schübeler DS-51-DIA 3-ph ducted fan unit is a near perfect fit in the Panther. The DS-51-DIA 3-ph is a molded carbon fiber ducted fan unit with a 4 blade, 90mm diameter aluminum and carbon fiber rotor. To provide power to the fan, I acquired a Kontronik FUN500-19 brushless motor, controlled by a Kontronik Beat 50-6-18 speed controller. This motor and ESC combination was chosen as I was going to use 16 cell NiCad and NiMH packs I already had on hand for the Panther.
Aeronaut supplied a plastic laminated paper that was marked to be trimmed and formed to make up the exhaust tube. This was an excellent idea that in turns made up into a lightweight tube. I trimmed my tube to the lines indicated but this actually ended up a bit short when taped to the DS-51-DIA 3-ph fan housing. I left it as is thinking that the fan efflux would help pull air through the rear part of the fuselage.
The fiberglass parts were not quite the blue I was looking for in recreating the look of the F9F Panther I was duplicating, being closer to that used on Panthers flown by the U.S. Navy Blue Angels. I stopped in at the local plastic model hobby shop and took a look at the paint racks there. Since I’m not yet set up to work with an airbrush, I chose to go with spray cans and used Testor’s Model Master enamels. The primary airframe color is Dark Sea Blue FS15042. Prior to painting, I washed the fiberglass in warm soapy water followed up with a light wet sanding using worn 240 and 320 wet-n-dry sandpaper and also worked on knocking down some of the mold seams found on the fuselage. This was done until the gloss was knocked off the fiberglass and the seams were smooth to the touch. The sanding was followed up with a thorough wipe down with a tack cloth and a follow up cleaning with a cloth dampened with denatured alcohol.
Once the overall airframe had been painted in Dark Sea Blue, the leading edge of the wing and inlet lips, as well as the inboard portion of the tip tanks were masked off and Model Master’s German Silver was sprayed on. The kit supplied white decals for this but the leading edge should be polished silver that comes close to looking like chrome. After I had finished the model, I came across a chrome silver paint that would have worked well too, called Plasti-Kote Odds ‘n’ Ends, I found it at my local WalMart.
The tip tanks and large chevron across the back of the Panther’s fuselage, along with the panel on the lower surface of the nose, were painted using Model Master’s Semi-Gloss White and International Orange. Thanks to my friend Joe Steimann, who is a wizard with an airbrush, for painting the tip tanks, as hand painting the barber pole stripes would have been a hit or miss affair.
As for the markings, I kept it simple and used the kit supplied stars and bars. For the letters and numerals, I borrowed again from the plastic modelers and used LongBeachUSN font which is available online from TLai Enterprises Modeling Fonts site. This was the specific font used on Navy aircraft and the cost of purchasing the font was worth it to me, as I can use it on future projects. Once the correct sizes were determined, I made up a couple of proof sheets of the required markings, went shopping at a couple of the local vinyl lettering shops and had one of them do the actual cutting of the markings. These were easy to apply to the Panther and the results were well worth the effort.
With the painting and markings now completed, I completed the mounting of the remaining components within the airframe. The Hitec Micro 555 receiver and JR 270mah receiver pack were mounted on the shelf in the front of the fuselage using Velcro. I took the receiver antenna and spiral wrapped it around a long straw then tacked the straw into place inside the fuselage just below the canopy rail. The servo leads for the elevator servo and the speed controller were run down the right side of the fuselage through the center fuselage bulkheads while the wiring for the battery was run down the left side to isolate the two as much as possible. The Kontronik Beat speed controller was taped in place on top of the exhaust tube where I had cut a 3/8” wide by 2” long slot to allow for cooling air to flow across the speed controller.
With everything in place except the 16 cell battery pack, I placed the Panther on the CG balancer, placed the battery pack on the tray and adjusted its placement to achieve the recommended CG location. It was critical that I take the time to do this correctly as the recommended CG range is only 2mm, and with the fairly small elevator area, a CG out of the recommended range would likely be a handful.
With everything in place and all flying surfaces set to the throws and centers recommended in the instructions, a couple of motor runs were completed in the workshop to confirm that things were right and ready for the trip to the field. With a nearly new 16 cell Sanyo RC3000 NiCad pack fully charged and hot off the charger, full power to the DS-51-DIA 3ph fan showed 49 amps and 784 watts static. With the Panther being held nose down on a postal weight scale, approximately 48 ounces of thrust showed on the scale. With a flying weight of 80 ounces, this bode well for the upcoming test flights at the field.
Once out at the club flying field, it was time to top off the receiver and power packs and range check the Airtronics RD6000 Sport transmitter both with and without the motor on. Range checks were solid and showed that the Panther was ready to go.
For launching, I used a heavy duty bungee which consisted of 50 feet of 3/8” OD latex rubber tubing and 50 feet of 170 pound test braided fishing line. Using a fishing scale, the bungee was set up to give a launch pull of 3 times the model weight (15 pounds). I set up the line by staking it next to the launch pad and walking it out until it was fully off the spool, and then walking the rest of the way using the fish scale. When I hit the target pull weight, I staked the ring down flush with the ground using a one foot long, 3/8” diameter spike. The launch pad I used was based on one I’ve seen Kevin Cox use for his larger models and consists of a 6 foot long, 2 foot wide sheet of plywood and for the Panther, I added two launch rails made up of 1” diameter PVC tubing with insulating foam placed over the PVC. With the rounded belly of the Panther’s fuselage and the mid mounted wing, this allowed for a smooth launch and kept the tip tanks off of the ply ramp during launch.
With everything in place and ready to go, club member and good friend Marc Gellart pulled the bungee back to the launch pad and held the model in place for launch. The launch pad was aligned into a light, steady breeze of 5-7 mph and with nothing else to do but to get on with it, I throttled up to full power and said “launch”. The Panther tracked straight up the launch pad and settled just a bit before accelerating away in a shallow climb. I took out a bit of up elevator with the trim and pulled the Panther around on a left hand turn for a full circuit around the field at an altitude of around 200 feet.
Response to the controls was solid and crisp and the Panther tracked solidly. A number of low passes at about ½ throttle were made to allow Marc to take some photos. At ½ throttle, the Panther looked very scale like as it passed by and rolled into climbing turns for the next photo pass. With the photo passes completed, the Panther was taken to a higher altitude and throttled down to see what would transpire – all I noticed was a slight increase in sink rate and a nice glide ratio. A couple of additional passes were made at low throttle with the ESC cutting out just as the Panther passed me going upwind at about 50 feet. I had plenty of space out in front to work with so instead of risking a turn downwind for a more controlled approach, I chose to land long. With the good glide ratio and no desire on my part to stall the Panther, I made a one bounce landing at the far end of the field with the Panther tracking straight and sliding to a stop on the sod.
A post flight review led me to think I had not allowed for sufficient airflow over the ESC even though I did not find it hot to the touch when I retrieved the Panther. The short exhaust tube and the slot I cut in the duct for cooling the speed controller apparently were not sufficient so I increased the size of the slot under the speed controller and raised the speed controller off of the exhaust tube itself on two short balsa rails. Airflow is now noticeably better over the speed controller and after two additional flights, I’m confident that this problem is now solved.
Additional video is also available on the Aero-Naut website.
The Aeronaut F9F Panther is an excellent model that is very well made and quite straightforward to build in a relatively short period of time. As a sport scale model, it looks the part of a Panther and has a real presence in the air. Flight performance is excellent and predictable with solid tracking and control responses. The lack of a moveable rudder is not noticeable, aileron roll rate is very good without being sensitive and elevator authority is quite good with the Panther set up at the recommended CG range. The changes I made while building the Panther were for personal preferences and are minor in nature. There’s no doubt in my mind that you could build the Panther precisely by the instructions and other than the method of bungee launch shown (which strikes me as a potential problem at some point), have a great model to add to your fleet.
Our model club is blessed to have an excellent flying field and bungee launching and belly landings are not a problem. For those who prefer to fly off of a runway, the Panther could be easily modified to accept fixed gear and some brands of retracts. The full scale Panther had a very simple landing gear and gear door arrangement and this would be easy to duplicate on the model.
The Schübeler DS-51-DIA 3-ph ducted fan unit is a real engineering and manufacturing marvel and works extremely well in the Panther. Combined with the Kontronik FUN500-19 and Kontronik BEAT 50-6-18 speed controller, I have a model with plenty of power and duration.
I have just been searching for info on this plane nice article Mark. Thanks much for the photos should come in handy should I chose to pick one up. I found this jet at www.Ductedfans.com in stock as well as a nice Cougar that is about the same size. Heres a link.
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