Carl Goldberg Falcon 56
This Product Review is the first part of a 3-part series about this airplane and how to update older designs to today’s requirements. The Falcon 56, and its larger brother the Senior Falcon, have probably introduced more RC pilots to the sport than all other trainers combined. I am not certain when a Goldberg Falcon’s wings first lifted the airplane from the earth, but I do know that it was at least 45 years ago.
Photo 1 Photo 2
How do I know the Falcon 56 design is at least 45 years old? Simple, photo 1 shows a Falcon 56 that my cousin Edward Granelli built around 1962. The airplane was assembled but never completed as the radio and covering systems of that day were difficult to manage, hideously expensive and unreliable. So it sat carefully stored until now.
Ed’s original Falcon 56 provides a perfect opportunity the judge the new Falcon 56 ARF against the original airplanes that made this design a legend in the sport. For the design is truly a legend. The Falcon 56 earned its reputation as a high-performance trainer during the 1960’s.
The airplane remained stable at very slow airspeeds using extremely low throttle levels. Even tiny engines like the Fox .15 shown in photo 1 would fly it well. It was very stable in turns, could self-recover from bad attitudes (except for spins) and went exactly where the pilot pointed it.
But open the throttle and the airplane would climb like a boosted rocket ship, level off and then roar across the sky about as fast as a pilot of those days wanted to go. Aerobatics were exciting given the radio and powerplant limitations of the day.
The original Falcon 56 would slow for landings but remain under full control. If you put ailerons on it, most Falcon 56’s were made without ailerons, they remained effective right through the stall and continued to work even in the deep stalls that could follow. The airplane would bank with rudder input about as well as an aileron equipped airplane and it had no tendency to “wander” in straight flight as did many airplanes of the 1950’s.
In short, the Goldberg Falcon 56 was an honest airplane that could teach new pilots how to fly but also had aerobatic abilities far beyond the average trainer. But that was years ago. What about the Falcon 56 ARF now available? Is it as good as the original design? Has it remained a high-performance trainer? Or has Goldberg made compromises over the nearly 50 years since those first flights? Let’s find out.
Photo 2 shows the airframe components of the ARF version. They certainly look a lot better than my cousin’s old parts which took weeks to assemble even without covering and painting. The ARF version is colorful and the bottoms of the wing and horizontal stabilizer are very different, making pilot orientation easy.
Photo 3 Photo 4
Although not really a part of this review, let’s take a few minutes out to compare the ARF airframe to the original just to see if Goldberg made any compromises over 48 years. Photo 3 shows that the fuselages are almost identical. While the ARF fuselage is slightly deeper to allow for more radio equipment, larger fuel tanks and engines, the important things like wing position, tail and engine thrust moment arms remain identical. Most importantly, the horizontal stabilizer retains its airfoil shape. Goldberg could have taken the easy way out and switched to a sheet balsa stabilizer to save time and cost but the airplane’s performance would have suffered immensely had they done so (photo 4). They didn’t do that. The old stabilizer was held in place with rubber bands, not acceptable with today’s high output engines, but Goldberg wisely changed to a fixed stabilizer without changing the important things back there such as stabilizer incidence.
Photo 5 Photo 6
The ARF’s nose area is wider to make room for today’s larger, more powerful engines. But both airplanes use the wooden beam mounting system. The wing is identical in size, shape, airfoil and dihedral. The only difference is the addition of strip ailerons.
Judging from this quick comparison, Goldberg modernized the Falcon 56 without changing its aerodynamics at all. All of the changes allowed the airplane to handle today’s advanced engines and radio systems. The ARF’s plywood construction is more robust than the original’s balsa framework. It seems like improvements were made without making compromises.
Construction
Photo 7 Photo 8
The ARF kit has two more features not found in the “Old Days” and that is the complete hardware kit featuring first line quality accessories and an excellent photo construction booklet (photo 8). Everything needed to complete the Falcon 56 is packaged in individual bags separated by function. It is easy to find all the pieces needed for a particular assembly step as they are all in the same package. About all that is missing is the 2 1/4 inch spinner.
Wing
Photo 9 Photo 10
All the airframe parts needed to assemble the wing are shown in photo 9. The dihedral brace is already assembled saving about 30 minutes construction time. The two bolts are used to hold the wing in position on the fuselage but are not used during wing assembly. The wing center sections are factory sanded so they assemble into the proper, and generous as this is a Falcon 56 after all, dihedral angle.
The wing’s top “seam” is visible on the Falcon 56 (the bottom is hidden once the wing is installed).While very common on all ARF aircraft, it still detracts from the airplane’s appearance. If it doesn’t bother you, skip down a few paragraphs to the wing joining section. But you might want to try gently prying up the covering’s center rib overlap on the top of both sides (photo 10).
First, trial fit the wing halves together on the dihedral brace. Make sure the joint is tight and has no gaps. Ours was a perfect fit which can be rare in ARF’s these days. After insuring that everything is tight, sand the dihedral brace to fit if it isn’t, separate the parts again.
You should remove all the overlapping covering anyway to insure a very strong center joint. Epoxy does not stick well to shinny plastic things. The covering’s thickness, while slight, also spaces out the center joint further weakening it. Cut away the overlap from the bottom but only pry back the covering on the wing’s top sections.
Photo 11 Photo 12
The wing has a small alignment pin shown in photo 11. This pin slides into a corresponding hole in the opposite wing half ensuring proper alignment. This is again a feature not found on most ARF aircraft. Mark the dihedral brace’s center as shown in photo 12.
Photo 13 Photo 14
Use a paste brush (available in all hobby shops) to apply 30-minute epoxy to the inside of the dihedral brace sockets in both wing halves. Do not apply epoxy to the brace itself as most of the adhesive would be removed as it is slid into place. Besides creating a mess, doing this will ensure that very little epoxy will remain in the sockets reducing the bond strength. Note the top covering pulled back from the center in photos 13 and 14.
Then use a different paste brush to spread 12-minute epoxy on one center rib (not both). Slide the dihedral brace into place making sure that the center point does not slide in too far. Then slide the other wing half over the brace making sure the alignment pin fits into the hole on the other wing half.
Photo 15
Use some number 64 rubber bands to hold the rear and front of the wing together as shown in photo 15. The wings already have the hold-down dowels in place for later mounting on the fuselage. For now, use them to hold the front of the wing together. Also use a few rubber bands on the rear as shown. Hold the top and bottom of the wing halves in place using low tack masking tap. Stretch the tape a bit as you apply it to insure inward pressure on the joint. Allow the wing to dry for at least an hour before installing the ailerons.
Photo 16
Just to keep Goldberg honest, I checked the assembled wing against the original. Everything matched perfectly, including the generous dihedral.
Photo 17
Once the wing is dry, use a model covering iron to seal the top center seam over the gap using the overlapping covering that had been pulled back from the center section. The result as shown in photo 17 is a covered center section that does not subtract from the airplane’s colorful appearance.
Alternately, you could spend about $18 and buy three small rolls of UltraCote®. Cut three 1/2-inch wide strips each of UltraCote Midnight Blue (#885), Deep Red (#871) and White (#870) as long as needed to cover their respective areas. Iron these small strips in place to cover the gap. Since $18 buys me more than a gallon of fuel, I’d rather enjoy the extra hours of flight time the extra fuels buys me at the cost of a little assembly time during construction.
Photo 18
The instruction booklet suggests installing the ailerons before joining the wing halves. But ailerons always seem to get in the way when assembling a wing. It is up to you but I suggest you consider joining the wing halves and then installing the ailerons.
All the hinge slots are factory cut into both the wing and the ailerons. The Mylar hinges used in the Falcon 56 were just a dream 50 years ago. They are easy to install correctly, almost never fail and last for thousands of flights. If you have not yet used them, read the Sport Aviator article, “Installing Mylar Hinges” in the flight-Tech Section.
Photo 19
Mark the center of each hinge and install some pins as shown in photo 18. Slide the hinges in place in the aileron up to the pins. Mix up some 12-minute epoxy and apply it into the aileron torque rod hole with a toothpick. The epoxy strengthens the wood increasing its durability. Also apply a little epoxy along the factory-cut groove as shown in the photo.
Photo 20
Then install the aileron on the wing making sure that all four hinges are in the wing’s trailing edge as well. Once everything seems good and the aileron deploys without too much resistance, remove all eight pins. Slide the aileron the rest of the way to the trailing edge. While putting pressure on the aileron, deflect it about 40 degrees and apply thin CAA adhesive to the each hinge. Repeat the process on the opposite side. That’s all there is to it. Do the other wing half the same way.
Photo 21 Photo 22
Put the aileron servo tray in position and draw around it on the covering as shown. Remove the tray and cut out the covering as shown in photo 22. For best results, use the Great Planes Hot Knife. This allows cutting the covering using heat without scoring the wood. The hot knife removes the covering without sacrificing wood strength. When using the hot knife for this purpose, I install a dull blade to make sure the wood is not cut.
Photo 23
Use 5-minute epoxy to install the servo tray as shown. Place a few small weights on top of the tray to hold it down for maximum joint strength. This is how I installed the aileron servo according to the instructions and it is how you SHOULD NOT install the aileron servo. If you do, and use standard Futaba 3004 sport servos (or any brand sport servo for that matter), the aileron linkage will hit the throttle servo’s output arm.
The throttle servo cannot be lowered because the main landing gear housing is directly under it. But there is a 0.2 inch clearance between the aileron servo and the center rib joint just under it. Mark the balsa wedges under the plywood aileron servo tray 1/10 of an inch (0.1”) up from the bottom. Cut away the balsa under the mark. This will lower the aileron servo by 0.1 inches and everything will clear.
Photo 24
I had to turn the aileron servo control rods upside down to clear the throttle servo. While this worked, the resultant clearance is miniscule so I strongly recommend lowering the aileron servo. Hook up the aileron control rods as shown in the instructions if you have lowered the aileron servo.
Photo 25
The canopy is factory painted and looks much better than the original’s. Position it as shown and glue in place using canopy glue such J&Z’s Super RC-56 or Pacer’s Formula 560. Tape the canopy in place and let dry for several hours. The wing is complete.
Fuselage
The Falcon 56 uses a plywood plate over hardwood beams for engine mounting. This is a mounting system not often used in today’s ARF aircraft. However, it is strong, light and very durable. The engine’s mounting bolts lock into metal blind nuts for a superior bond over today’s clamp-on or screw-into-fiberglass mounts. But a few different techniques are needed for a good installation.
The Falcon’s engine is going to be the wildly powerful but extremely docile and reliable OS Max .46 AX. This is a lot of motor for an airplane originally designed for a Fox .15! True, the Falcon 56 ARF weighs more because of the 4-channel radio system plus the larger engine and fuselage, but not that much more. Using this powerhouse under the right conditions, who knows but that the airplane might even be able to fly without the wing! (Only kidding, you engineers out there).
Photo 27 Photo 28
The OS .46 AX was too wide for the plywood mount. The mount is made small to accommodate any 40-size engine. Engines such as the OS LA-40 might slip right into the mount but not the AX. Use a caliper to measure the widest part of the engine crankcase as shown in photo 27. The AX crankcase measured 1.485 inches wide. Then use the caliper to measure the plate’s inside dimensions; here 1.853 inches. The plywood plate needs to be 0.368 inches wider than it is. When dealing with wood, you can delete the thousandths for this application.
Photo 29 Photo 30
Since the engine must be centered in the mount, only half this difference, 0.18 inches must be removed from each side. Measure the distance needed to clear your engine outward from the interior space as shown in photo 29. Then place the engine against the mount with the backplate, not the rear bolts as they will be under the plate, only a paper slice away from the plywood plate and mark where the engine’s wide crankcase ends (photo 30).
Photo 31 Photo 32
The fitted plate should look about like photo 31. Insert the plate, with the engine in place but not yet bolted in, into the fuselage. The Falcon 56 hails from the days of the front-mounted high-speed needle valve. Yes, they made “real modelers” in those days but they didn’t always have a lot of fingers! Luckily, we are a lot more safety conscious today and most engines have rear mounted needle valves. Like many ARF fuselages, the Falcon’s valve-side fuselage wall might have to be cut to clear the needle valve.
Photo 33 Photo 34
Mark the area to be removed for the needle valve. Then carefully peal away the covering as was done for the wing center section (photo 33). Use a high-speed motor tool to remove the plywood/balsa laminate from the offending area (photo 34).
Photo 35 Photo 36
Then carefully trim the “excess” covering, the part that covered the area now removed, to cover the open space (photo 35). Use the covering iron to apply the covering. Seal the inside of the wood with some 5-minute epoxy for fuel protection. The small uncovered area under the needle valve is nearly invisible (photo 36). You could also use some of the Midnight Blue covering if you purchased it for the wing center. Or, you could steal some blue covering from the underside of the wing where it fits into the fuselage.
Photo 37 Photo 38
Insert the engine into the plywood plate and the plate into the fuselage. Mark the mounting bolt locations using one of modeling’s greatest inventions – The Great Planes Engine Mount Hole Locator (photo 38). If the holes are outside of the recessed area machined into the fuselage mounting beams, as was the case with this Falcon, mark the extra area (photo 38).
Photo 39
Use the high-speed motor tool to remove some of the wood from this area. Don’t remove all of it, just cut down to the bottom of the factory spaces as shown in photo 39.
Photo 40 Photo 41
Drill out the holes you marked to accommodate the included engine mount bolts. Then flip the plate over and enlarge the holes to 1/8 inch halfway only (photo 40). This allows space for the blind nuts. Insert a blind nut into each hole and pull into place using a bolt and large washer from the top. Then apply some thin CAA to keep them in place.
Photo 42 Photo 43
Cut off any parts of the blind nuts that protrude into the open space using the high-speed rotary tool (photo 42). Bolt the engine in place.
Photo 44 Photo 45
Place the plywood plate with the engine mounted into the fuselage. Note the mounting bolts and make sure they clear the beams. If not, as in photo 44. Remove enough wood from the beams for bolt clearance only. The blind nuts will fit as is. Coat the beam areas that will contact the plywood plate and the plate edges with 12-minute epoxy. Put the plate into the fuselage and clamp in place at the front. Hold the fuselage sides against the plate edges using rubber bands. Keep the plate firmly against the beams using rubber bands over the engine as shown.
It takes a long time to read all this, but the actual installation was done in 30 minutes, including photos minus epoxy dry time. Installing a fiberglass mount takes just about as long. But now you know have a very firm and tough engine mount that will not break short of a catastrophic collision with the planet. In addition, the firewall is strongly reinforced against damage from those “nose wheel first” landings.
Photo 46 Photo 47
The Falcon 56’s horizontal stabilizer is, unlike most ARF stabilizers, an airfoil and not a flat sheet. Having an airfoil stabilizer greatly enhances the airplane’s flying ability and aerobatic performance. Despite its airfoil shape, the Falcon’s stabilizer mounts the same way as would a flat version. First, remove the overlapping covering (photo 46) just as was done on the wing center ribs.
Use the hot knife to remove the stabilizer covering in the area under where the vertical stabilizer will mount (photo 47)). The instructions say to glue the vertical fin into the stabilizer and then mount the fin/stabilizer assembly onto the fuselage. I did it that way and suggest that you DON’T.
With the fin in place, fuselage placement became difficult. The bottom of the Dorsal fin forward of the stabilizer was not a perfect fit to the fuselage angle. That meant sanding the dorsal until the stabilizer would sit comfortably onto the fuselage. This was very hard to do. Mounting the unit meant crushing a small section of the vertical dorsal fin’s top in order to keep it firmly against the fuselage top while the adhesive cured.
I then had to use the water/heat trick to expand the crushed areas under the covering. Since this “trick” requires the use of a hypodermic needle, which is illegal for most people to own, I can’t suggest you try it. If you know someone who can legally own such a tool, however, ask them to fill the needle with water and inject the water into the dented areas as I did this time. Then you wait about one minute and apply the covering iron to that area. The water’s turning to steam expands the balsa back to its original shape.
Photo 48
Instead, mount the stabilizer first. Draw the center line at the rear. Place the fin into the stabilizer slot but do not glue. Test fit the stabilizer in place, centering both the rear mark and the tip of the dorsal fin. Once everything is aligned, mark the area on the bottom of the stabilizer just outside of the fuselage. Use the hot knife to remove the covering inside this area leaving about 1/32 inch of covering inside the lines.
Coat the fuselage mounting area with 12-minute epoxy and re-align the stabilizer onto the fuselage. Remember to make sure the stabilizer is perfectly level when the wing saddle is level (note level in photo 48). The dorsal part of the vertical fin may be partly raised away from the fuselage at this point but don’t worry about it. Just make sure the entire vertical fin is centered.
Photo 49 Photo 49A
Once the stabilizer is firmly attached, cover the areas just outside the vertical fin slot with low tack masking tape. Install the fin, and remove the covering from the areas that will be inside the slot.
Photo 49B Photo 50
Carefully cut the covering away from the fuselage top that will be under the dorsal fin (photo 49B). Apply 12-minute epoxy to the stabilizer slot and the bottom of the fin and dorsal. Insert the vertical fin into the slot. Use a triangle to make sure the fin is 90-degrees to the stabilizer (photo 50).
Photo 51 Photo 52
Once everything is dry and straight, reposition the overlapping coverings to seal the gaps and protect them from oil and dirt. The covering forms good looking fillets that cover the joint areas. Install the elevator halves and the rudder the same as the ailerons. Remember to put some 12-minute epoxy into the elevators’ connecting rod holes and grooves just as was done with the aileron torque rods.
Turn the airplane upside down. Looking at it from the rear while the fuselage is inverted, the elevator control horn goes on the right side. The rudder horn is on the side opposite that.
Photo 53 Photo 54
The instructions say to install the servo tray into the fuselage. I guess you could if you first used a hammer and chisel to remove the factory installed servo tray from the fuselage. Instead, since the tray was factory installed and installed well at that, I left it in and just mounted the servos. Remember to install a piece of card stock between the servo sides and the wood (photo 53). Preventing wood contact with the servos protects against vibration damage.
Photo 55 Photo 56
The Falcon’s elevator and rudder control rods must be made (photo 55). This takes about five minutes. Take the appropriate threaded wires and bend the non-threaded end a quarter inch from the end by 90 degrees. Place it the groove and glue in place with medium CAA (photo 56).
Photo 57 Photo 58
Slip the heat-shrink tubing over the wire/dowel section and shrink in place with a model covering heat gun or hair dryer (the heat gun is better). Install a non-threaded rod on the other end of the dowel in the same manner. Slide the completed control rod through the fuselage from the front and out the appropriate rear fuselage slot. Use a small screwdriver to pry the threaded end out of the slot as shown in photo 58. Install the clevises on the threaded end.
The other control rod end is connected to the servos by setting each rear control surface in neutral, putting the control end over the centered servo arm and marking the spot. Bend the rod 90 degrees at that point, insert it through the servo and lock in place with the included locking keeper. Trim the excess control rod to just 1/16 inch above the keeper’s top.
Photo 59 Photo 60
Temporarily install the nose wheel. The Flacon uses plastic tubing to protect the throttle and nose wheel steering control rods from being jammed by the fuel tank’s movements during flight. The throttle worked fine but the nose wheel steering rod could be a bit lower to lessen the servo load. Place the rod in the nose wheel steering arm and lay on top of the rudder servo. Mark the area on the inside former where the rod passes (photo 59). Drill a 1/8 inch hole here and slide the plastic tubing through it.
Install the fuel tank according to the directions. Then install the main landing gear into the slots and grooves on the fuselage bottom. They are held in place with two nylon straps. Position the straps just inside the outer end of the gear legs, just before the downwards bend, mark and drill the holes with a 1/16 inch drill. Install the wheels.
Loosen the nose gear’s inner collar. Place the fuselage on a flat, level surface. Put a straight edge over the wing saddle front to back. Use a level on top of the straight edge. With the level neutral, set the nose wheel height. The Falcon uses extended runway length for takeoff if the nose points downwards at all.
Photo 61
Install the switch in the space provided on the servo tray and extend a 1/16 inch wire to the outside capped by a small wheel collar (photo 61). Since the fuselage gets a lot of handling during transport, assembly and just plain hangar movements, it is a good idea to set the switch so that pushing inwards turns off the on-board radio system.
Place the receiver and the flight battery forward of the servo tray. Use lots of foam for vibration protection. Install a 2 1/4 inch spinner over the correct propeller for your engine choice.
Photo 62
Bolt on the wing to make sure there is no control interference. When all done, the Falcon 56 is colorful and sleek looking, even with the fixed landing gear “down and welded”. The Center of Gravity (CG) should be about 3.25 inches back from the leading edge at the fuselage sides. The range given is 3 to 3.5 inches but the first flights would do best with the CG a little further forward than the rearmost 3.5 inch mark.
Don’t forget to balance the airplane laterally. Today’s mufflers are much heavier than the no-muffler condition the Falcon 56 was originally designed for. Yes, there were no mufflers back then. That made things easier to set up but then we were nearly deaf after a few flights. A lot of things about the “good ole` days” were not so good and the Falcon 56 ARF version is proof of how far we have advanced in the sport.
Back to the lateral balance. If you are unsure what lateral balancing means, please read the Sport aviator article “Ready To Fly?…Maybe” in the Flight-Tech Section. This Falcon needed three, 3-inch finishing nails in the left wingtip to balance.
Flying The Falcon 56
Photo 63 Photo 64
I never had the opportunity to own an original Falcon 56. My trainer was the original Das Ugly Stik designed in 1960 by Phil Kraft. But a lot of pilots at our field must have learned to fly on the Falcon 56 because, as soon as it was set up on the ground, there was a big crowd around it with a lot of misty stares from my fellow pilots.
Even I could tell that they were not mentally at this field, not here, not now. Rather, they were at some distant flying field; distant in time as well as space, living again their first fumbling stick movements and how their own Falcon 56’s forgave them their mistakes and kept on flying until they got it right. This is a legendary airplane in our sport and it has truly earned that honor.
Photo 65 Photo 66
A legendary past is one thing. But the airplane must offer performance and be fun to fly today. The Falcon 56 looks very good on the ground. It is colorful, fast-looking and has more propeller clearance than a DC-3. Its nose wheel steering will make takeoffs stay straight.
Photo 67
And it is just as well that the ground roll is easy to control because the Falcon does use a lot of it to liftoff. Remember it has a semi-symmetrical airfoil and is “short-coupled” meaning that the stabilizer is fairly close to the wing’s trailing edge. The airfoil has less lift than would a flat-bottom wing and the short-coupled elevator has less control authority.
Interestingly, the airplane would liftoff more quickly, and at slower airspeeds, if only 50% of the available “up” elevator was used. This occurred even though the elevator movement was at the recommended 0.5 inch. I didn’t try to figure it out and just went with it. The ground rolls dropped to about 50 feet with liftoff speeds around 29 mph instead of 35 mph when using full “up” elevator.
Photo 68
But wow, once it did get free of the grass, did it ever perform! Photos 67 and 68 show the first takeoff after the engine had been broken in for two runs. With the OS .46 AX turning near 12,000 rpm on an APC 11 x 6, the Falcon climbed at over 1,900 feet per minute (at 33 mph) from takeoff! It held the 45-degree climb angle forever and even vertical climbs were never-ending. No Advanced Trainer yet tested here at Sport Aviator has this high initial climb rate.
Photo 69
Left at full throttle, the Falcon roared past the field at a level top speed of 65 mph. This is a fast airplane. From top speed the Falcon zoom-climbed to 750 feet almost in less time than it takes to say “750 feet” (a slight exaggeration but not much). Yet the airplane stayed under full control and was rock steady at all times. The original Falcon was quick in its day but not known as a racer. But with a modern engine, I can see club one-design pylon races in its future. Fast enough to be exciting but not so fast as to be unmanageable, the Falcon rounds turns like it was riding the rails.
Speaking about control response, the pilot will quickly notice that the Falcon will bank and turn on rudder alone as well as it would using the ailerons. Remember, the original Falcon 56 was designed without ailerons so rudder turns are very easy to do. Additional elevator input, above what is used for aileron turns, is NOT needed to stay level in the rudder-only bank and turn. This is fun to fly and a good feature to have if those ailerons ever decide to quit during a flight.
Photo 70
Ok, lots of sport airplanes are quick and handle well in steeply banked, high-speed turns, but the Falcon 56 is also a high-performance trainer. Well, that is where the truly amazing part starts. This airplane will fly on nothing! Put the throttle trim on high and lower the throttle stick to 3 clicks from the bottom (about 30% power) and the Falcon 56 just motors along at 30 mph. In fact, this is the airplane’s best training speed. Even at 30 mph, the Falcon will make level turns with just a hint of “up” elevator in the turn. At this power setting, the Falcon will stay airborne for about 20 minutes.
If the airplane is slowed too much in a steep turn, under 25 mph, it does not stall. Instead, it levels its wings and starts flying level again. Remember this airplane was originally designed to be self-leveling and to fly with a minimum of control input. Push the edges of its slow-speed flight envelope and it reverts to its original design performance. It regains level flight.
In fact, it was somewhat difficult to hold the Falcon in the stalled 60-degree bank as it loudly protested such mistreatment by constantly trying to recover to level flight. The ailerons could overpower its self-righting tendency but it required diligent attention to do so. Miss holding the ailerons into the roll for a fraction of a second and the Falcon was back flying straight again.
Photo 71
However, at normal flight speeds of around 30 mph or more, the Falcon would stay in the bank attitude commanded by the pilot without aileron input. It was only when stalled that it tried to get back to level flight. This feature will be a boon to pilots who have just soloed. Most airplanes are not lost during the learning process as the instructor is there to help out. But newly soloed pilots tend to have problems. The self-righting Flacon will still be there to help them out when the instructor isn’t.
The flight data record is listed below instead of at the end of the article. This airplane has very different performance characteristics than the usual Advanced Trainer and the numbers may help to understand this better.
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Photo 72
When the Falcon is trimmed and flying at about 30-35 mph, the pilot starts to feel redundant. The airplane just doesn’t need any help flying straight and level. Even loops could be flown without pilot input except for the elevator. This must be due to the generous dihedral. But high-dihedral airplanes usually have trouble flying inverted aerobatics. The Falcon does indeed have a bit of a dual personality when flying inverted.
Level inverted flight requires minimal engine power, about a click more than upright flight, and just about 20 degrees of “down” elevator input. Making steep inverted turns requires 10% more elevator and another click of engine. This is better inverted performance than most Advanced Trainers tested so far.
Photo 73
However, the Falcon works against the pilot in an outside loop. Applying the extra “down” elevator for the loop makes the airplane want to roll out back to level flight. This tendency is best managed using the ailerons as rudder input immediately rolls the airplane back to upright flight. It is possible to perform outside loops, and vertical inverted Figure Eights, with the Falcon but some practice is needed first. But then, isn’t that how an Advanced Trainer is supposed to teach the pilot?
Photo 74 Photo 75
Rolls are quick with minimal altitude loss. A very small amount of “down” elevator input will keep the falcon rolling the entire length of the field. The roll rate is about 3 rolls in five seconds. The roll is not axial, but the airplane’s nose is too never far from the airplane’s line of flight.
Snap rolls are fun and slow enough that most new pilots will be able to recover to wings-level after a few tries. Stall turns do require some opposite aileron input to keep the wings level with rudder input. But that is not a problem. But watch those vertical lines! Leave the Falcon too long in a vertical climb and it becomes a very high dot in the sky. This airplane can climb at nearly 2,000 ft. / min. and even more in zoom climbs. There is no vertical limit using the .46 AX.
Many pilots are like me. They want to stick the biggest engine possible into the tiniest airplane they can find. The OS .46 AX allows this airplane to perform any vertical maneuver the pilot can dream about. Even vertical climbing snap rolls go up forever if the pilot can keep the airplane on the vertical line while snapping (somewhat difficult).
Installing an even more powerful engine, such as the OS .55 AX, in the Falcon could get you into trouble. Flutter might be possible in full power dives and flight time on the 8-ounce tank will drop by about 20%. The .55 AX will not provide any maneuver benefits over the .46 AX. And you could get into trouble as the authorities will take a dim view of your flying the Falcon through the International Space Station in a .55 powered zoom climb.
My cousin’s original Falcon 56 will be powered by the LA-40 and even that might be too much. Stay with a good .40 or .46 to get the best performance out of this airplane.
The Falcon is difficult to get to spin. Power-off stalls will just slowly spiral down when rudder or rudder and ailerons are inputted. The only way to enter a spin is to fly above stall speed and pull the nose to nearly vertical. Then input full aileron and rudder in the direction of the spin. Interestingly, the Falcon’s spin rate nearly doubles when using rudder alone. The ailerons just seem to slow the spin rate.
If the Falcon is forced to enter a fast rudder spin, and it must be forced into one as this aircraft just doesn’t want to spin, standard spin recovery techniques will NOT work. Just letting go off the transmitter sticks will keep the Falcon in the fast spin for the next 4 turns. If you have a lot of altitude, this recovery method is useful. However, down lower, apply opposite rudder and the Falcon immediately ceases spinning and is ready to fly again.
Many scale airplanes, and some larger aerobatic scale aircraft, also need rudder input for prompt spin recovery. But unlike the Falcon 56, these type aircraft will spin on their own given half a chance. The Falcon is merely preparing its pilot to handle these situations as should any good Advanced Trainer. But few others do today.
Photo 76
But even the most fun and exciting of flights, of which the Falcon will have many, must come back down to Earth. Sadly this is true of the Falcon as well. Here too, the Falcon has a dual personality. Flying the approach at about 32 mph and 600 ft. /min. down provides the pilot with an easily managed landing approach. Keep a little power on and the airplane will touchdown at about 28 mph. These are good approach speeds for an Advanced Trainer.
There is sufficient elevator control for a decent pre-touchdown flare at these airspeeds using about 50% “up” elevator. But the Falcon hides the fact that the final 50% of up elevator just doesn’t do much at slow airspeeds. This must somehow be related to the Falcon’s takeoff performance mentioned previously. There also, full “up” elevator inhibited slow speed performance.
Many advanced airplanes fly just like the Falcon 56 in this respect. Large scale fighters are particularly prone to such behavior. Again, these complex aircraft are exactly what an Advanced Trainer is supposed to be preparing the pilot to fly. Keep the elevator limitations in mind during the last ten feet of altitude and there will not be any problems.
Photo 77
However, being the forgiving, stable Advanced Trainer that it is, the Falcon will allow the pilot to learn a very high-performance landing. This is the type of landing the pilot must perform when a wheel falls off the airplane or if the retractable landing gear stays firmly in their wheel wells. Every pilot should learn the ultra-slow, soft field landing. But few trainers are able to teach it. The Falcon 56 can.
Using about 30% engine power, the Falcon will fly a steeply-descending, stable approach at about 20 mph. Engine power is used to control altitude while the elevator manages airspeed in all landings. But this type of landing is the ultimate example of this reality. By the time the Falcon is just above the runway, photo 77, the airspeed is down to 15 mph and the touchdown roll is very short. All during this high-performance approach, the Falcon kept its wings level and never hinted at snapping out even when the airplane was accidentally stalled (hey, nobody’s perfect).
Summary
It’s almost 50 years old but the Falcon 56 can still fly rings around most of today’s airplanes. Like a Cessna 152, this airplane can truly teach its pilot not just how to fly, but how to fly correctly. Both aircraft reveal their pilot’s mistakes, allowing the pilot to learn, without causing serious problems. The Falcon 56 is livelier and more fun to fly than the Cessna, but both were conceived and made in the same training mold.
The Falcon 56 can serve as a very good Basic Trainer. It can fly and turn slowly with minimal pilot workload. But as an Advanced Trainer, thus airplane truly tests its pilot’s flying knowledge while safely educating the pilot in a way that few other aircraft can. Fly around slowly and it will drift along with you happy as can be.
But push it, and this airplane pushes back. It is almost as if this aircraft is making sure you know how to fly any RC aircraft, in any bad situation, before it lets you move on. Its “push” is challenging but it is done safely and slowly so you can learn. And that is what an Advanced Trainer is all about.
Find out more about this airplane at: website
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Specifications Manufacturer: Carl Goldberg Prod. Cost: $160.00 Length: 47.5 in. Special Airframe Features: Semi-Symmetrical Wing, Light Weight, Slim Fuselage, Beam-Mounted Engine. |
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Notable Positives Notable Negatives |
Short URL: http://masportaviator.com/?p=836
Posted by Frank Granelli
on Dec 1 2007 Filed under Advanced Trainers.
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