Hobbico NexSTAR EP Select
One of the most popular, and effective, Ready-To-Fly (RTF) Basic Trainers of recent times is the Hobbico NexSTAR. The glow-powered NexSTAR is actually a complete training system that can propel a non-RC pilot through simulator practice, flight training and on to some advanced maneuvers. The System includes a great airframe complete with speed brakes and leading edge cuffs for better aileron control at low airspeeds. It is also an airframe that can grow along with the pilot’s piloting skills.
The glow-engined airframe is also equipped with the Futaba PA-2 Pilot Assist Link. The PA-2 is basically a flight stabilization system that returns the airplane to level flight once the controls are released (more on the PA-2 later). The system also includes a limited version of the Great Planes “Real Flight” Simulator (also more later on).
Simulator practice speeds the learning process. While it is not a substitute for learning with an instructor, it does provide the student pilot with extra “flying time” that does translate to real world skills. RC simulators have been in common use for several years now. As an instructor, I can safely say that student pilots with simulator access, as well as real-world flights, learn faster, encounter fewer difficulties while being easier to teach.
In the past three years since the NexSTAR has been available, I have enjoyed teaching three new pilots how to fly using one. The airplane flies so slowly, handles so exceptionally well and so exactly translates the pilot’s inputs into visible reality, warts and all, that it has proved a truly great learning tool.
Photo 1 Photo 2
The glow-powered NexSTAR (photo 1) remains in service and has become an important part of learning to fly RC. But many of today’s pilots prefer the quiet advantages of electric power. Until the introduction of the NexSTAR EP Select, there just wasn’t an equivalent electric-powered Basic Training System available. Now there is (photo 2).
The glow and electric photos have set next to each other twice for a reason. Most electric conversions of existing glow airplanes sacrifice durability, airframe size and/or performance. The electric-powered version is usually smaller and more lightly built. Flying times are shorter and all-round performance usually suffers. Not so for the new NexSTAR EP.
The airframes are identical. There are no differences apparent to the naked eye. Size and outward appearance are the same with one major exception. The electric version is trimmed in blue while the glow-powered airplane sports red trim. Maybe the color difference is designed to prevent pumping fuel into the battery charge port? Only kidding on this but honestly, that is the only difference found.
The EP airframe is just as strong as the glow version’s. Rough landings, student errors and general “hangar rashes” will have the same non-effects on the EP as they do on the very robust glow version.
Hobbico was able to use the rugged glow-powered airframe because first, there is a very powerful electric power system installed. Second the airframe itself has surplus lift from its large wing equipped with the leading edge cuffs. Because the NexSTAR fuselage is not as boxy as other trainers, there is less drag for the power system to overcome. It looks better too.
The NexSTAR EP Select Training System
Photo 3 Photo 4
Of course, the strong, easy flying NexSTAR airframe is included as is the PA-2 Assist Link system. The three servos are the time-tested Futaba S3003. These standard servos produce 44 oz. in. of torque while weighing just 1.3 oz. Their 0.23 second transit time (60 deg.) is quick but will not overwhelm the new pilot by reacting too quickly. These same servos are used in the glow NexSTAR as well.
Photo 5
Even though the EP is electric powered, a separate Nickel Cadmium (Ni-Cd) battery pack is used to power the radio system. Larger airplanes like the EP require a lot of current to move the control surfaces. The Battery Eliminator Circuits (BEC) used in many smaller aircraft to save weight are not a great idea in these larger airplanes. Current draw could exceed the BEC’s limits causing slow response or outright Electronic Speed Control (ESC) failure. The EP uses a rechargeable 4.8 volt, 700 mAh Nickel Cadmium (Ni-Cd) battery pack. A charger for both the receiver battery and transmitter is included.
Photo 6 Photo 7
The ESC is factory installed and connected. The black aluminum heat sink, about the size of Pittsburgh, provides a clue to just how powerful the EP’s motor is. That motor is the RIMFIRE 42-50-800KV brushless outrunner. Outrunner means that the case rotates while the armature remains stationary. Think of a WW I Rotary engine. The 10 x 5 in. propeller is bolted to the spinning case just as a rotary’s was bolted to the spinning cylinders. The motor is strong enough to turn the propeller at nearly 12,000 rpm.
Photo 7A
The transmitter is the Futaba T6XAP 6-channel computer transmitter. Having 6 channels means that the sixth channel, a proportional channel normally used to raise and lower the flaps, can be used to control the PA-2’s sensitivity while the NexSTAR is airborne. The glow version does not yet have that feature as its transmitter remains the 4-channel analog Skysport. Having an adjustable PA-2 System is a real help when the sun sinks too low in the sky for reliable PA-2 operation.
Before starting the airframe assembly, put the transmitter and receiver Ni-Cd batteries on charge for at least 5 hours. The final 16-hour charge is performed before the first flying session. The 5-hour charge provides more than enough “energy” to complete the assembly process, setup and testing.
NexSTAR EP Assembly
Photo 8 Photo 9
This airplane is a true RTF and only needs a few assembly steps to complete. Photo 8 shows all the parts needed to “build” the wing. The aileron servo is already installed and connected to one aileron. Photo 9 shows the center nylon “rib” that holds the aileron servo. It also serves as the center joint rib of each wing half and the front hold-down “dowel” that slides into a corresponding mounting hole in the fuselage.
Photo 10
The metal bar in the photo is actually the wing spar. It slides into holes factory drilled in each wing half. A steel anti-rotation pin is factory mounted in one of the wing panels. It slips into a hole in the other panel preventing the wing from rotating around the larger metal spar. This is common RTF construction.
Photo 11 Photo 12
The first step in building the wing is to install the spar in one wing half. The pictorial instructions (photo 11) are excellent and explain every assembly step in so much detail that there are no questions left unanswered. Insert the spar into one wing half as far as it will go. Mark the spot where the spar exits the wing (photo 12). This is good practice to insure that the spar fits entirely inside both wing panels. This NexSTAR EP had no problems and the spar fit perfectly.
Photo 13 Photo 14
But just in case it doesn’t, the mark will identify the problem. While the spar is still inside the wing, mark the protruding end. Remove the spar and insert the marked end into the other wing panel. It must slide in at least as far as the mark for both wing panels to fit completely together, as they must. If the center mark sticks out of the second wing panel, use a drill bit slightly smaller than the hole’s diameter, at least 1/32 in. smaller, and deepen the hole in the wing panel until the spar inserts to the center mark. This airplane’s spar fit perfectly.
Photo 15 Photo 16
Even though the wing spar was a perfect fit, the NexSTAR EP’s wings could not be joined without a center gap. Both wing panels must slide completely into the nylon center rib. The spar’s fit was fine so the next point to check is the anti-rotation pin. Measure the depth of the pin’s hole in the other wing half using a toothpick and mark as shown (photo 15). Then stand the pin next to the anti-rotation pin as in photo 16. Yup, there was a very small difference. This often happens with RTF airplanes.
Photo 17
Use a drill bit slightly smaller in diameter than the hole, here a No. 22 drill bit (0.157 in. diameter), and deepen it as much as needed. Do not use a power tool for this task. Wear a glove if the drill bit is very sharp but turn it by hand. Do not enlarge the hole’s diameter, just deepen it. Any power drill, even a small high-speed rotary tool, will enlarge the diameter. Hand power is more than enough to get the job done without enlarging the hole. Deepening the hole by 3/32 in. allowed both wing halves to fit together perfectly.
Photo 18
The wing halves are firmly held in place by small screws through the center “rib” (photo 18). Connect the remaining aileron control rod to the torque rod. Make sure the locking band is in place.
Photo 19 Photo 20
Locate the three factory drilled flap mounting holes and use a small punch or pin to puncture the covering over each hole (photo 19). Mount the flap/speed brake using the three supplied screws. Note the slots to allow correct positioning on the wing. There are varying theories about this unit’s location, but I suggest following the instructions to align the inner flap/speed brake and aileron edges (photo 20). This puts more of the flap/speed brake inside the propeller’s arc making them more effective. Both my NexSTAR’s have used this location and it seems to work well.
Photo 21
This is the completed wing from the bottom. Note that the correct Center of Gravity (CG) range is clearly marked. Not much doubt left as to this airplane’s correct CG. The aileron servo is connected to both torque rods and the flaps are aligned and firmly mounted.
Important Note:
This is not yet the place to discuss flying the NexSTAR EP. But we need to take a few minutes to discuss this airplane’s flap/speed brake performance and this is a good a place as any. As an experienced instructor and precision pilot, I tour much of the Northeast flying at various club fields while giving presentations about sport trimming and aerobatics.
I can’t count the number of times that I have heard about instructors telling their students to remove the NexSTAR’s flap/speed brakes. That if they don’t, the airplane will stall while landing and be too “hard” to handle for a new pilot. Then I hear those same instructors complain that the NexSTAR is “too fast” for students and gains airspeed too easily.
Yes, both glow and electric powered NexSTARs are very clean airplanes. They are not boxy like many basic trainers and the nose area is streamlined. Their airframes produce far less drag than do comparable trainers. The NexSTAR’s airframe not only looks good, but is also very efficient.
The flap/speed brakes are there for a purpose. They help prevent the airplane’s gaining airspeed when the new pilot allows the nose to drop too much in the turn. Most basic trainers gain speed when this happens and then “balloon” upwards once the wings are leveled due to the increased lift caused by the higher speed. The NexSTAR’s speed brakes greatly reduce, if not totally eliminate, this phenomenon.
They function the same during the landing approach. It is easier for a new pilot to manage approach airspeed with the flap/speed brakes in place. Yes, sometimes a little power must be added during the approach to maintain altitude. But isn’t that what an airplane is supposed to be teaching its new pilot? Throttle controls altitude and elevator regulates airspeed during approaches and the NexSTAR, with flap/speed brakes in place, is one of the best tools to teach this important truth to a new pilot.
With its flap/speed brakes in place, the NexSTAR EP, like its glow-powered brother, maintains a constant airspeed during pitch and power changes. This has to help the new pilot as the airspeed variable is removed from the learning equation. The top speed is also lowered, without lowering available lift. Slower flight with constant lift is a very good thing for a basic trainer. Install the flap/speed brakes and leave them there.
Fuselage Assembly
Sorry about the soap box thing above, but the flap/speed brakes are an important part of this learning system, so I may have gone a bit overboard about them. Now, back to assembling the NexSTAR EP’s fuselage. If this were a glow powered RTF, we would normally start by installing the propeller and spinner before working on the tail section.
However, the propeller and spinner are the last items to install on an electric-powered RTF. Remember that electric motors must always be considered to be “alive”. Even though the propeller isn’t turning doesn’t mean that it can’t accidentally start. Just as a firearm must always be treated as being loaded at all times, so must an electric motor.
Photo 22 Photo 23
A good place to start is by attaching the NexSTAR EP’s tail surfaces. This is a simple operation requiring only some thin CAA. Not even a screw driver is needed as nylon “thumb” screws are provided. Apply some thin CAA into the two holes in the horizontal stabilizer and let dry (photo 22). This hardens the hole to prevent enlargement that can allow the stabilizer to move around a little during flight. This is standard procedure on all RTF assemblies for aircraft in this size range.
Photo 24 Photo 25
Slide the stabilizer into place in the fuselage slot. Make sure the elevator control horn is on the bottom. Two long, tapered, hollow “nuts” (photo 23) are then inserted from the fuselage bottom into and through the two stabilizer holes holes. Two threaded “bolts” extend downwards from the vertical fin (photo 25).
Photo 26 Photo 27
In addition to the long “bolts” extending from the bottom of the vertical fin, there is also a wooden pin near the front bottom of the dorsal fin. When installing the vertical fin, make sure this pin fits into the small fuselage slot (photo 26). Position the vertical fin in place and using the long nylon nuts, tighten those two threaded “bolts” to hold the fin and stabilizer firmly in position.
This system is stronger, more solid and wear resistant than the older system that had the threaded bolts pass directly through the stabilizer and into two nuts on the fuselage bottom. When properly installed, the NexSTAR EP’s tail surfaces should be tight, firm and straight as in photo 27.
Check the tightness by operating the elevator using the transmitter. If not sufficiently tight, the stabilizer will move just a bit. Tighten only until the stabilizer remains stationary when the elevator is moved to full deflection (1/2 in.). Do not over tighten. Stop when the stabilizer does.
Photo 28
Once the tail surfaces are installed, connect the control rods to the proper control horns (photo 28). For the first flights, install the control rod clevises into the third control horn hole outwards from each surface if you plan to use Lithium Polymer Batteries as the NexSTAR EP’s energy source. However, if using the Nickel Metal Hydride (Ni-MH) energy system, connect the elevator clevis to the second hole outwards from the horizontal stabilizer. When using the heavier Ni-MH batteries, the NexSTAR EP makes good use of the extra elevator authority this provides during the final landing flare. The additional elevator movement is so slightly more than “stock” that it makes almost no control difference during regular flight. But it helps much at the very end.
Photo 29
Center the transmitter sticks and trim tabs except for the throttle stick and trim lever which should be in the low position. With electric power, always consider safety first. Turn on the transmitter and then the receiver. If either the elevator or rudder are not exactly in the neutral positions, use either a clevis tool, shown in photo 29, or your hand, to rotate the clevis in or out until both control surfaces are neutral. This is important.
Photo 30 Photo 31
The main landing gear only needs to be slid into the fuselage slots (photo 30). Make sure they “click” firmly into place. These fit perfectly. If the main gear ever needs removal, simply inserting a small screwdriver into the opposite hole unlocks the gear leg. The wheels are already factory installed.
There is a factory AD (Airworthiness Directive) out on the NexSTAR EP’s motor that will require cowling removal. So, now is a good time to remove the propeller, spinner backplate and the cowling. The cowling is held in place by four screws. With the cowling gone, the nose wheel assembly is in full view (photo 31).
Turn on the transmitter and receiver again. Center the rudder control stick and trim tab. If the nose wheel is not straight, loosen the steering arm’s locking screw, center the nose wheel and tighten the locking screw. Then turn off the radio equipment.
Check that the nose wheel strut’s locking screw is tight if the wheel did not require straightening. Also check the steering arm’s locking screw. Then remove one of the nose wheel strut bearing’s bolts. Apply thread locking compound to the bolt and re-install it. Do the same for the second bolt. These bolts can loosen over time unless locked down. Since the AD makes you remove the cowling, this is a good time to insure your nose wheel stays were it is and turns only when the pilot commands it to.
Now to cover the AD. Rather than paraphrase it and probably confuse the both of us, it is being reprinted below exactly as it is on the Hobbico website:
Make sure that the thread locking compound is applied only to the set screw. Do not put any into the motor hole itself. I don’t know if any locking compound could leak into the motor’s bearing that way, but why take the chance?
Photo 32
Since we are locking threads everywhere right now, loosen the four motor mount bolts, loosen only – not remove, and then apply some locking compound to them as well (photo 2). It may be necessary to slide the mount away from the firewall to expose enough thread to insure the compound reaches into the nuts behind the firewall. Retighten firmly.
This procedure of locking the motor parts and mounting bolts in place is one that should always be performed on every electric airplane. While not as pronounced as that of glow engines, electric motors of this size do produce vibrations when operating. In time, their vibrations often cause the mounting bolts and set screws to loosen. Infallibly, such failures will only occur at the worst possible time. That is a major rule of aviation that is as strictly enforced as is the law of gravity. A little time spent now will pay huge rewards over the airplane’s lifetime.
Photo 33 Photo 34
Install the spinner backplate over the motor shaft after reinstalling the cowling. Position the propeller in place but only a hard hand-tight. This allows the propeller to be positioned so that the spinner’s twin screw holes can line up with the backplate’s matching holes.
While there are always propeller “stops” in every backplate, they almost never fit the propellers being used. The APC-type 10 x 5 in. reinforced fiber propeller on the NexSTAR EP is not exception. Rotate as required to match the spinner holes and backplate mounting studs. Then mark the location in case the propeller accidentally moves as it is being tightened. Tighten the nut firmly with a model spanner wrench or appropriate box wrench. Then install the spinner cone. Make sure the spinner cone is a perfect, flush fit with the backplate. There must be no wobble during operation.
Photo 35 Photo 36
Photo 35 shows the back side of the firewall. Note the blind nuts installed for the motor mount. Unlike most RTF aircraft that use nuts, or at best locking nuts, to secure the motor mount, the NexSTAR EP uses the same epoxied blind nuts that most modelers would install were they building the airplane themselves. This is a nice quality touch.
The interior battery compartment (photo 36) can accommodate either twin 3600 mAh Ni-MH batteries or the lighter, more efficient 5S 1P Lithium-Polymer (Li-Po) batteries.
Photo 37
The only installation step required here is to install the hook and loop battery “keeper as shown in photo 37. Join one end of the keeper as shown and pass each end through the slot in the battery floor support.
Photo 38 Photo 39
The NexSTAR EP uses a neat battery “clip” to mount the two batteries together (photo 38). The clip holds either two 3600 mAh Ni-MH batteries or one 2-cell, 3200 mAh and one 3-cell 3200 mAh Li-Po batteries to make a 5S 1P power supply. The clip uses rubber bands to hold the batteries in place and mounts between the two motor batteries. The clip is held in place against the battery compartment floor by the hook and loop fastener tape.
Photo 39 also shows the two magnets used to hold the battery hatch cover in place. These super powerful magnets are very convenient and have not yet failed on several electric airplanes. They are fast, simple to use and ultra reliable.
The battery clip however, needs a little reinforcing because, over time, repeated rubber band installations and battery removals cause the end caps to separate. The four corner gussets in photo 38 are installed to prevent this. The gussets are made from 1/4 in. hardwood triangle stock available in any hobby shop. Use epoxy to glue them in place.
Adjustments and Preflight Checks
The PA-2 Pilot Assist Link
Photo 40
The PA-2 Pilot Assist Link has a manual sensitivity setting as well as an adjustment on the transmitter. There are several instruction manual pages devoted to adjusting this link if the PA-2 is to be used in another airplane. As it arrives in the NexSTAR EP, the manual setting is set to about 40% as shown in photo 40. That proved to be a great starting point and no adjustments from “stock” have been required.
Photo 41
The other half of the PA-2 system is the optical sensor mounted on the fuselage bottom behind the wing saddle (photo 41). Make sure that both AFS wires are connected. For the first flights, turn the PA-2 off by rotating the transmitter control knob all the way counter-clockwise. This allows the instructor trim the airplane during the first few flights.
Remember that the PA-2 system is not at its best in the early mornings or very late afternoons. In the continental US, the system works best between the hours of 10 AM and 4 PM; when the sun is not low in the sky. The transmitter easily overrides any PA-2 inputs but constantly doing so can be a distraction during the learning process.
Used according to the directions, the PA-2 proved its worth. No matter what position the airplane was in, the PA-2 would right the airplane within a second or two once the transmitter sticks were released. Recoveries from vertical power dives, inverted flight, vertical climb angles and every weird attitude I could think of were all the same. The airplane leveled out almost immediately.
The sensitivity adjustments did not change the final results but did affect the recovery’s quickness. On low sensitivity settings, the recovery required about 3 seconds. On high, the airplane leveled out in about 1.5 seconds.
The PA-2 is best used to recover an airplane from dangerous situations. If in trouble, the student pilot merely has to release the controls. Once the aircraft is back to level flight, the pilot has only to point it in the right direction and resume training.
PA-2 sensitivity is best kept on the low side. If set too high, the pilot must hold in a lot of aileron to prevent the airplane’s rolling out of the banked turn. This can give the new pilot a very bad habit, much as does an airplane that uses only a rudder for bank control. The pilot must unlearn holding in the aileron control when turning the PA-2 off or the airplane will continue rolling into a spiral. On low sensitivity settings, this effect is very minimal and not a real factor.
Motor Battery Selection
The NexSTAR EP arrives totally flight ready except for the motor batteries and their respective charger. This allows the pilot to choose the power system. Both the Ni-MH and Li-Po power systems have their advantages and disadvantages. Each pilot must make their own choices. Here is a brief outline of each system’s performance and cost factors. For actual performance differences, see the Flight Data charts at the end of this article
Ni-MH Batteries
The NexSTAR EP can use twin 8-cell, 9.6 Volt, 3600 mAh Ni-MH battery packs (GPMP0362) wired in a 16S format to produce 19.2 Volts. The “series” wiring is already factory installed so the only step is to connect the batteries as they are installed on the battery tray.
Photo 42
(Photo courtesy of Tower Hobbies)
Great Planes offers these batteries packaged with the Dual Peak Charger for $150. The Part Number is: HCAP9953. The Dual Peak charger (HCAP0255) is an exceptional product value ($40). It simultaneously analyzes both battery packs and then individually delivers the charge current that each pack requires to reach full capacity without damage.
Extra battery packs sell for $46 each and two are required for the NexSTAR EP. It is always a good idea to have one extra battery set so you can fly while one set is on charge. Since the Dual Peak charger (working from a 12-volt source like a car battery) can charge each battery at up to a 5 Amp rate, the NexSTAR EP’s 3600 mAh batteries will be charged in about 40 minutes. (Note – some charge always remains in the motor batteries. Each flight usually drains about 3000 mAh from each battery.)
Using the Ni-MH batteries saves a good deal of money; total starting cost is just $150. They perform adequately and provide about an 8-minute training flight time. Ni-MH batteries are easy for the beginner to handle, can be safely charged without special equipment, and last through many charge cycles. However, Ni-MH batteries do not deliver their energy as efficiently as does a Lithium Polymer battery pack. Ni-MH battery packs are significantly heavier, 1.6 pounds heavier in the NexSTAR EP’s case, than the Li-Po system. The Sport Aviator article “Those Things We Call Batteries – Part Two” details Ni-MH batteries.
Lithium Polymer Batteries
Li-Poly batteries are a newer technology. However, they require special handling to prevent battery damage, need special chargers and have a limited shelf life. If grossly abused, they can cause fires and damage to surrounding areas; albeit only in very, very rare cases. Almost all mishandling results in the battery pack’s being damaged. For more information about Li-Po batteries, read the Sport Aviator article “Those Things We Call Batteries – Part Three”.
The NexSTAR EP’s Li-Po power system is a 5S 1P system that uses 3200 mAh packs. At first glance, it would seem that the 3600 mAh Ni-MH system would provide longer flights. However, because they weigh over 1.5 pounds less than the Ni-MH system, and because they are more efficient, Li-Po flight times are in the 11-12 minute range. All-around flight performance is also superior.
But there is a cost. The NexSTAR EP uses one 3-cell, 11.1 V, 3200 mAh battery pack (GPMP0623) and one 2-cell, 7.4 V, 3200 mAh pack (GPMP0622). The 3-cell pack costs $100 while the 2-cell pack is $80. Total battery cost – $180. A special charger is required to avoid problems.
Photo 43 Photo 44
(Photos courtesy of Tower Hobbies)
Only special chargers designed for Li-Po battery packs may be used. The charger most suited to a Li-Po powered NexSTAR EP is the Hobbico PolyCharge 4 (photo 43). The PolyCharge 4 will recharge up to four battery packs at the same time so simultaneously charging both of the NexSTAR EP’s packs is not a problem. This charger costs $100 and may only be used to charge Li-Po batteries.
The Triton Jr. charger will also charge Li-Po batteries, but only one at a time. This doubles the recharge time. Keep in mind that Li-Po batteries have a 1 x Capacity (1C) maximum charge rate. The PolyCharge 4 has a maximum 3000 mAh charge rate anyway. Recharging two battery packs will require about 1.5 hours with using the Triton Jr. This charger costs $75 but is also capable of charging all other battery types.
However, there is more. To safely and most efficiently charge Li-PO batteries, a cell balancer is required. For details see the “Those Things We Call Batteries – Part Three” article. Two ElectriFly Equinox balancers are needed to charge both batteries at the same time. Each balancer costs $30 for a total of $60.
Switching to Li-PO power means better and longer flight performance. But the cost is $315 to $340, almost as much as the entire RTF airplane ($400). However, the Equinox balancers and Li-PO charger may be used on all future electric-powered airplanes; spreading the cost over many years of faithful service.
The cost difference and special handling skills required for Li-Po power is why we said that the battery choice is up to the pilot. That is also why Hobbico did not include a battery set in with the RTF airplane. Sport Aviator flew the airplane with both power systems and recorded the performance data. Check the flight data before making your decision.
Install the battery packs you selected and check the Center of Gravity (CG) as directed. Regardless of the power system chosen, the NexSTAR EP balanced perfectly. Before jumping in your car and heading for the flying field, read the Sport Aviator article “RTF? … Maybe” and perform all the alignments and pre-flight checks listed. The NexSTAR EP does not have a heavy muffler sticking out one fuselage side so the Lateral Balance was perfect. But still, it couldn’t hurt to check it just to be sure.
Included Real Flight ® RC Flight Simulator
The NexSTAR EP includes a special “NexSTAR EP” only version of this popular RC Simulator. The Real Flight series of RC Simulators, the most recent in the series is the G4 version, is famous for its realistic flight parameters. The NexSTAR EP version included in the NexSTAR EP Flight Training System is no exception.
Photo 45
(Photos courtesy of Great Planes)
The simulator includes a Real Flight, NexSTAR EP only USB connection device. The connector plugs into the back of the NexSTAR EP’s transmitter and into the computer. After calibrating the transmitter, this limited Real Flight version operates exactly like the G4. Remember to fully charge the transmitter battery before taking to the virtual skies. The transmitter battery last longer than when flying in the real world since the radio signal output circuit, the major power draw in the real world, is not operating when used with the simulator.
Unlike the full G-4 RC Simulator, there are no pilot training courses available in the NexSTAR EP’s limited version. Aircraft versions with and without the PA-2 Pilot Assist Link are available. However, when flying with the PA-2 engaged, its sensitivity can be adjusted from the transmitter but not totally turned off as is possible in the real world. To fly totally without the PA-2, select the version without the PA-2 engaged.
Photo 49
All flying takes place at only one airfield; G-3.5’s Grass Flatlands. The approaches are wide open with very few obstacles and the background scenery is terrific. The only NexSTAR EP airframe version has both the flaps/speed brakes and leading edge cuffs installed. As far as I could find, there are no versions without this equipment.
Photo 50
The virtual NexSTAR EP is equipped only with the 5S 1P Li-Po power system. A Ni-MH version is not available. The airframe reacts identically, virtual or real world. But the virtual airplane seems to have a much better climb than does the real world aircraft. Simulator readings say that the virtual NexSTAR EP is turning 12,500 rpm but the best the real world version could do was 11,950. The 550 extra revs might be the reason that the virtual airplane had better climb performance. Glide rate and landing performance were equal.
How closely does the virtual NexSTAR EP fly compared to the real world version? Click on photo 50 to expand it. The Simulator has the NexSTAR EP just touching down at 25 mph. Our flight tests, as listed in the chart, says our real world NexSTAR touched down at 24 mph. that is a great performance match.
Flying the NexSTAR EP
Standard, no disassembly, building time for the NexSTAR EP would be about 30 minutes. Add in the extra 20 minutes for deepening the anti-rotation pin hole in the wing and building time is less than 50 minutes. Complying with the AD added another 15 minutes, making total construction time just over one hour. That is not much time to assemble an aircraft as sophisticated as this one.
While you are charging the motor and receiver batteries, use the charged transmitter to work the simulator. After you are fairly proficient in the virtual skies, start killing the motor using the keyboard “K” key. Electrics usually run out of power before a new pilot learns their warning signals. Many landings are “dead-stick” and some simulator practice including this fact is a good idea.
Photo 51 Photo 52
Regardless of the viewing angle, this is a very attractive airplane, especially for a basic trainer. The rounded fuselage and sleek nose resemble a Cessna Sky Wagon. The wing has that “just right” look that all fine airframes have. The airplane looks like it will fly well.
Photo 53 Photo 54
Front or back, the airplane has that racy look to it. Both glow and electric-powered airframes are identical. Except for the color that is and color has little effect on flight performance. The EP version is simply the glow NexSTAR with an altered power system. The airframe, no power systems installed, weighs the same and appears to be of identical internal structure. The glow-powered NexSTAR has gained a reputation for being a very strong and robust airframe. The EP version will do the same.
Photo 55 Photo 56
The wind was blowing at a sedate 8-10 mph as the NexSTAR EP taxied into position and held on the runway. I still enjoy seeing the airplane on the runway, ready for takeoff, with the propeller standing still (photo 55). Applying full up throttle trim and then full power started the airplane rolling. The roll continued for about 100 ft. and then the airplane started to rise. The initial climb angle was held down as shown in photo 56. The nose was then raised and the airplane climbed out.
With all the lift devices on this airplane, it can leave the ground at fairly low airspeeds. Letting it gain a little more airspeed before pointing the nose skyward is not a bad idea; at least until the new pilot gets a feel for the airplane’s climb performance.
Subsequent takeoffs usually happened at around 28-29 mph using the Li-Po power system. The Ni-MH system lifted off at about 31 mph due, maybe, to the increased weight. The initial climb rate was about 800 f /min for Li-Po and 400 ft/min using the Ni-MH batteries. Again, the extra 1.6 pounds makes a difference here.
Photo 57 Photo 58
Once in the air, the NexSTAR EP proved it is a true NexSTAR. Remember that this airframe is designed to have lots of lift without requiring excess airspeed to get it. The airplane flies rock steady at about half throttle while flying at 30 mph (Li-PO) to 32 mph (Ni-MH). These are its best respective training speeds. Flying more slowly is possible but the nose tends to drop in steep turns if flown under these speeds. It is an interesting note that the glow-powered NexSTAR also cruises best at 32 mph. These are the same airframes.
Photo 59 Photo 60
Actually, the airplane is not much faster in level flight than those best training speeds. Level top speed is just 45 mph for the Li-Po version and 42 mph flying with Ni-MH power. Maximum dive speed (photo 60) just reached 50 mph for both power versions. If they are installed, those flap/speed brakes really work as planned.
The easiest way to learn, or teach, RC piloting is with an aircraft that maintains about the same airspeed in any attitude. Many trainers speed up a lot when the nose heads down and then suddenly balloon upwards when leveled. Elevator and aileron trim changes with airspeed and the new pilot suddenly finds the airplane starting to roll as it climbs.
The NexSTAR EP simply does not play those tricks on the new pilot. Even the 45 degree dive only increases airspeed by 5-8 mph. That is not enough to cause noticeable trim changes on a basic trainer airframe. At all airspeeds, the airplane kept its trim constant until near the stall.
Photo 61 Photo 62
The power-off stall occurred around 12 mph Li-Po and 15 mph Ni-MH. If you have read the glow-powered NexSTAR review, you will remember that it stalled at less than 6 mph. Why would the same airframe stall at nearly double that airspeed? The glow version weighs about the same as the Li-Po NexSTAR EP once 12 ounces of fuel are added. But it is almost 1.5 lb. lighter than the Ni-MH version.
More significantly, the glow stall occurred with the motor idling at about 2,300 rpm. That is enough to push extra air over the center of the wing and stabilizer, making both more effective. The electric motor on the EP however, effectively stopped in midair. There was no extra air over the flying surfaces to reduce the stall speed.
Whenever flying an electric-powered airplane, always remember that the power off stall speed is higher, the approach curve steeper and the airplane slows faster simply due to the motor’s being completely off.
But the stall is a not of much importance with this airplane. There is no stall break, no wing drop tendency and the event itself is barely apparent. Unless you are looking for it, the airplane’s downward “mush” is invisible until the NexSTAR EP gets under about 200 ft.
Photo 63 Photo 64
Having the PA-2 Assist adjustable from the ground is a great improvement. The best results were obtained at about the 30-40% level. The airplane will right itself from just about any attitude using the PA-2 at this setting. The PA-2 even worked when the instructions said it wouldn’t – late in the afternoon.
The PA-2 judges the aircraft’s attitude using light. When the sun comes from low on the horizon, the PA-2 can be fooled. Even in the worst test cases, a very low sun angle only induced gentle turns that were easily corrected using the transmitter. Incidentally, don’t bother trying to trim the airplane with the PA-2 engaged. It “tain’t” possible. Trim the NexSTAR EP with the unit off, then turn it on once trimming is completed.
Photo 65 Photo 66
This airplane is not designed for aerobatics. It is a Basic Trainer. However, it will fly nice, round loops about 35 feet in diameter. The airplane will roll but, like its glow-powered brother, it completes the second half of the roll at a “quick march” rate. Stalls and spins just don’t happen, even with full power applied. Stall turns are OK, but roll-coupling requires opposite aileron input to prevent unwanted rolling. Snap rolls are huge barrel rolls. Inverted flight, although possible in the Simulator, requires additional elevator movement in the real world than specified. Hey, this is a dedicated Basic Trainer, remember?
But it is not designed to be so limited forever. The NexSTAR airframe is actually quite aerobatic once the flap/speed brakes and the leading edge cuffs are removed. This happens after the new pilot has mastered the airplane without the PA-2 working. The NexSTAR EP is actually 1.5 airplanes in one. The “clean” version is faster and far more aerobatically capable. Only its flat bottom wing, which limits inverted maneuvers, prevents this aircraft from being a full two airplanes in one. While “clean” inverted maneuvers are superior, the flat-bottom airfoil still does limit inverted performance.
Photo 67 Photo 68
Landing this airplane is pure fun. But there is a technique to make it easier. Remember the part above about glow airplanes landing at 2,200 rpm while electrics land with power off? That applies to this airplane as well. There is a lot of drag in the NexSTAR EP. Extra elevator is required to raise the nose for those great flare landings (photo 68) if landed completely power off. This is especially true of the Ni-MH version.
Borrow a tachometer. Reduce the throttle trim lever all the way until the motor stops (throttle stick all the way down of course). Increase the throttle trim lever until the motor idles at 1,700 rpm.
This is the landing setting for fun, trouble-free landing flares. Memorize this trim position. Since full “up” throttle trim is required to achieve full motor power (best for takeoffs), you will need to find this position again before just before landing.
Photo 69
Once regular landings are mastered, push the NexSTAR EP’s limits a little. This airplane is well-mannered at very slow airspeeds. Using power to control altitude and elevator to control airspeed, the NexSTAR EP can be landed at nearly crazy airspeeds; around 10 mph. There is no wing drop tendency and the elevator remains responsive, even at such slow airspeeds. However, practice this higher up at first. Very slow landings are actually an advanced maneuver best left for later in your training program.
Summary
The NexSTAR EP is a good electric-powered Basic Trainer that has good growth potential. It is very easy to fly, forgiving and, with the PA-2 active, capable of saving itself. Most new RC pilots think of the PA-2 Assist only as a learning aide.
However the truth is that the PA-2’s airplane saving abilities will be the most valuable after the pilot solos. Instructors serve as the best ‘Pilot Assist” during training. But eventually, the pilot moves on and that is when it happens. We all know what “it” means and “it” always occurs when the new pilot is flying alone. Using the PA-2 at the 25% level may prevent “it” from ever happening.
Like its glow brother, the NexSTAR EP is a complete learning System. The System, complete with a superior dedicated training airframe, coupled with the RC Simulator and PA-2 Pilot Assist unit, is probably one of the best, most trouble-free, ways to learn RC piloting. At $400 for the airframe and $150 for the motor batteries, the System is not the least expensive way to learn RC piloting but it is one of the best.
For more information about the NexSTAR EP and its power choices, please go to: http://www.hobbiconexstar.com/nexstar-ep/index.html
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Specifications Manufacturer: Hobbico Length: 56 in. Cost: $400 + $150 battery Special Airframe Features: Flap/speed brakes; PA – 2 Pilot Assist Link, Ready-To-Fly; Leading Edge Cuffs |
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Short URL: http://masportaviator.com/?p=854
Posted by Frank Granelli
on Filed under Basic Trainers.
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