Plane Talk: Cermark F-16 Propjet ARF
Michael Ramsey
The F-16 Falcon is probably one of the best jets to start with if a model pilot has little experience flying. Even though the wings are short, the fuselage shape that flows into them is a lift component, creating a larger overall wing area and therefore providing forgiving airborne handling. Although the F-16 mimics the stability of a delta design, it has excellent agility as a result of the stabilators that are mounted close to the mean aerodynamic chord.
Jets are more or less a high‑cost special interest in the aeromodeling community. Modelers today have more success with pure jet forms featuring turbine engines and accurately scaled outlines than ever. But those models aren't for novice RC pilots because of their complexity and narrow flight envelope.
For a fraction of the cost, a propjet is a respectable alternative. Although the propeller detracts somewhat from the jet look (depending on the vantage point), many attractive jet features are maintained. Best of all, the propjet is a much friendlier RC model to fly; it typically handles similarly to a low‑wing sport model.
Cermark carries F-18 and F-16 propjets that close the compromise gap between the pure jet and propjet. Both models feature outlines that are relatively close to those of the full‑scale aircraft, thanks to the expertly molded fiberglass bodies and accessories. In addition, the models feature retractable landing gear, which is sorely needed to sell the jet look in the air.
Pluses and Minuses
- Outstanding "jetish" appearance and finish.
- Ease of flying in all attitudes.
- Excellent parts fit and high level of prefabrication.
- High‑quality pneumatic retract system.
- Great high‑speed performance and convincing "jet" handling.
- Bolt‑together construction with removable wings and tail.
- Full replacement part and accessory support.
- More complete instructions would benefit intermediate ARF builders.
- Landing‑gear‑plate reinforcement is required.
- More than 10 ounces of ballast in the tail is required.
Specifications and Test-Model Details
- Model type: RC sport‑scale ARF
- Skill level: Advanced builder, intermediate pilot
- Wingspan: 47.6 inches
- Wing area: 697 square inches
- Length: 64.7 inches
- Weight (estimated): 9 pounds
- Wing loading: 29.75 ounces/square foot
- Engine: .61–.91 two‑stroke (electric version available)
- Radio: Five channels (minimum), eight servos
- Construction: Fiberglass fuselage, conventional wood tail and wing surfaces
- Covering/finish: Three schemes available, painted‑in‑the‑mold fuselage, two‑ or three‑color matching covering, decal sheet included
- Features: Removable cockpit, pneumatic retracts, full‑flying stabilator, removable surfaces
- Options: Scale cockpit and pilot
- Price: $399.95
Test model equipment and details:
- Engine used: O.S. 91FX
- Propeller: APC 12 x 8 sport
- Fuel: 600 cc tank, Magnum #1
- Radio system: Futaba 7C FASST transmitter; Futaba R617FS receiver; two Futaba S3001 servos on ailerons; one Futaba S3003 servo on retract valve; two Futaba S3002 servos on nose steering and throttle; two Futaba S9001 servos on stabilators; one Futaba S3102 servo on rudder; 6.0‑volt, 4200 mAh NiMH battery; four extra‑long HD extensions; two reversing Y harnesses; one heavy‑duty switch
- Ready‑to‑fly weight: 10 pounds, 1.3 ounces
- Flight duration: Exceeds 10 minutes
The F-18 is available in the blue‑and‑yellow Blue Angels scheme, but the F-16 is regularly offered in three color schemes. The General Dynamics and Thunderbirds schemes are red, white, and blue, and the Air Force scheme is a two‑tone gray. The grays are more challenging to see, but the scheme is a better match to the desire for a total scale effort—even if there is a spinner up front.
Although Cermark does offer a turbine‑powered F-16, the propjet version is close to 40% less expensive. And the latter includes pneumatic retracts, darn good hardware, and an aluminum spinner that complements the front‑end outline.
Equipping a propjet is close to free compared to the expense of a turbine and all the other high‑end hardware required to insure the investment. The F-16P (as Cermark calls it) will fly great with a high‑speed .61 two‑stroke engine (a popular find at swap meets or in the spare‑engine drawer), and the radio system need not be complex; five channels will do nicely.
This review tested the model with an O.S. 91FX, which worked out wonderfully. A lighter .61 greatly reduces the need for ballast in the tail section; this aircraft needed 6 ounces in the tail, and that was with a 4200 mAh, 6.0‑volt NiMH battery (the heaviest that would fit) back there.
However, the disappointment of adding dead weight did nothing to harm the Cermark F-16P’s friendly, high‑performance flight characteristics. It’s a pound overweight, but I got over it quickly.
The wings, stabilators, and vertical fin are removable, making the project an almost bolt‑together job. I used thin cyanoacrylate to install the rudder and ailerons, and any hole I drilled was hardened with a drop or two of the thin stuff. (Don’t skip that step.)
Clear silicone adhesive is great for securing the fuel tank and the air tank for the retracts. The decorative missile rails attach with a few dabs of epoxy, and the lower subfins are best secured with thick cyanoacrylate.
The fuselage was a magnificent piece of fiberglass mold work; not a blemish or scar marred the semigloss surface. Inside the fuselage, the formers were secured; they offer good support to the thin fiberglass skin and should withstand any stress the structure might endure. The plywood used is a veneer type, which is somewhat flexible depending on the load; it holds a screw better when cyanoacrylate is used to harden the threads.
The rear landing‑gear plates would do better if made from a harder laminate, such as birch or maple multilayer grade material. The first hard landing with this test model damaged the gear plates.
To ensure that the landing gear will take the abuse of imperfect touchdowns and rough fields, add, with epoxy, a third layer of 3/32" birch plywood behind all the gear plates and tie them to the existing area. The test model has held up extremely well with this simple modification.
The conventionally engineered wings plug into the fuselage with the reinforcement of a 3/4‑inch aluminum tube, which is supported at its ends with hardwood plugs that accept wood screws through the predrilled holes. Wood dowels at the root keep the wings from rotating; their incidence is set at the factory and aligned to each other.
The stabilators (elevators) are fully sheeted balsa, built with a hefty‑gauge, solid‑aluminum rotation pin. The fully supported and aligned sleeve for each stabilator half is installed in the fuselage at the factory.
An aluminum control horn clamps to the aluminum pin with heavy‑duty hardware. Aluminum is used throughout the provided hardware—nice. Align the stabilators with an incidence meter rather than the mold seams.
Cermark had cleanly tooled clearance openings for the engine and retracts. These openings needed only slight customizations, and the prefabrication saved many hours of work.
The retractable landing gear are the air‑up/spring‑down type. They look strongly made with hard aluminum and heavy‑gauge‑steel wire struts. Not only is this system of actuating the landing gear safe, but it also cuts the amount of plumbing by about 50%.
The speed at which the gear actuates is regulated by valves (labeled: air throttle) spliced into the lines leading to the individual mechanics. Be sure to thread‑lock the struts and carefully align the nose‑gear steering. The nose gear will need low‑profile‑type mounting hardware to clear the steering linkage; 4‑40 socket‑head wood screws suit nicely.
The O.S. 91FX was used to demonstrate what thrills excessive power can offer. Because it has the same footprint as the 61FX, no modifications to the prefabricated openings or firewall were necessary. For a big brute, the .91 handles like the .40 does on most trainers. It starts easily and needs almost no adjustment out of the box.
The ring on the piston needs roughly a half gallon of fuel to properly seat; until it does, it can run and transition roughly—but fear not. The engine hand starts and can be run in on the model, as this .91 was. Fitting the muffler and its parts with red threadlocker is crucial.
An APC 12 x 8 propeller allows the engine to unload for good high‑speed performance and generates a minimal amount of thrust at idle so that landings can be slow. High‑nitromethane users should add a shim to the head (as I did) to eliminate detonation; using a colder plug would prevent detonation too. I favored the O.S. A5 glow plug.
To offset the heavy engine in the nose, Cermark located the radio tray in the tail cone. The exhaust cone doubles ingeniously as the hatch for this compartment. To further reduce the weight in the nose, miniservos were used for the throttle and nose‑gear steering.
The review F-16P came with the rudder‑servo arm exit on the wrong side, which meant that the rudder moved the opposite direction of the nose gear unless a reversing Y harness was used—an easy fix. A reversing Y harness is used for the stabilators too.
Heavy‑duty servos are important for the stabilators, but standard ball‑bearing types are fine for the rest. I used a pair of S9001‑size servos on the stabilators and an S3002‑size on the rudder. S3001‑size servos are adequate for the ailerons and retract valve. The miniservo mount for the rudder is brilliant, although it requires a high‑torque servo of the appropriate size. Flaperons were programmed but unnecessary for flight.
The F-16P's assembly manual was pretty good, even though its layout and information were presented in a format that might be awkward for the intermediate builder. All the data was there, but some hunting was necessary and the updated retract‑system information was missing.
Flying
The Falcon flies like a sport model despite its convincing jet appearance. The air blast from the propeller allows the F-16 to accelerate more quickly, and thrust from the propeller keeps the stabilators more effective while flying at slow speeds and landing.
The tricycle gear is stable like a trainer's during ground handling, so steering is not much of a surprise unless you make abrupt turns. Wingtip‑scrape protection might be a good idea.
All testing was done on smooth pavement, but videos on the YouTube website show Cermark's F-16P flying from grass with no difficulty. As with a sport aircraft, the F-16P takes off at a familiar speed and can climb out quickly near the runway's end.
The recommended low rate for elevator proved to be comfortable (I added roughly 30% exponential later), but the aileron control was like the ground handling; trainer‑like. I preferred high rate on aileron, and that control had exponential programmed to soften the center feel of the stick as well.
Bringing the gear up as the model rotates off the mains is totally cool. A slightly high angle of attack in heading, as with the full‑scale F-16, is easy to hold, showing no tendency to tip stall. So this Falcon immediately had me forgetting about that propeller spinning out front.
The low exhaust note from the stock O.S. muffler helped me appreciate this "jet" even more. Only a baritone grumble could be heard from the engine, and just enough of a whistle from the airframe hinted at how the whine of a turbine might sound.
This model calls for a ballroom‑dancing pilot style: big and graceful. No 3‑D, disco‑style flying is allowed. Any flier who has seen the US Air Force Thunderbirds perform will appreciate the aerobatic bag of tricks that this Falcon has for an RC pilot in command. Big loops, point rolls that "bang" into the stops, and high‑speed passes are what make this model great.
If you have flown a vintage RC aerobatics airplane, you will probably appreciate how this model flies—and do well flying it. It's groovy, with extra goosebumps.
Landing requires the pilot to set a glide slope with a nose‑high attitude; otherwise, landing speeds will be incredibly fast. The F-16P likes to fly and doesn't want to stop.
Keeping the nose high, which is easy with a propeller‑driven model, presents more drag into the oncoming air, slowing the Falcon. This technique eliminates the need for flaperons.
The ability to fly in this configuration requires you to accurately place the CG; do so with extra scrutiny. The video I've seen shows this model having difficulty keeping the nose up while landing. This test aircraft never flew that way. Nail the CG and this F-16 will fly great.
Afterburner
I explored the model's CG enough to find that the recommended point is approximately 1/4 inch too far aft. Learning this was a benefit, because roughly an ounce of lead came out of the tail.
Even tail‑heavy, the Falcon displayed only stable flight characteristics, but holding down‑elevator while landing was sometimes necessary to hold the glide slope. That's an awkward technique to learn.
The landing gear has absorbed both picture‑perfect landings and abuse from ugly landings that bounced all the way down the field. The heavy‑duty struts haven't bent, and the rubber tires are holding up well. An electric air pump is used to charge the tank to 85 psi, and it lasts a full 15 cycles—enough for an afternoon of flying.
The F-16P's lateral balance improves tracking through loops and drifting on landing approach. Even though the model is glow powered, the airframe stays relatively slime free.
The latest word is that an electric‑powered version of this model will be available that will retain the propeller up front but omit the ghastly muffler.
Michael Ramsey [email protected]
Manufacturer/Distributor
Cermark 9830 Bell Ranch Dr. Santa Fe Springs, CA 90607 (562) 906‑0808 www.cermark.com
Sources
- O.S. Engines
(217) 398‑8970 www.osengines.com
- Futaba
(217) 398‑8970 www.futaba-rc.com
- Batteries America
(800) 308‑4805 www.batteriesamerica.com
Other Printed Reviews
- Fly RC: April 2007
- Radio Control Jet International: December 2006
Transcribed from original scans by AI. Minor OCR errors may remain.
