The Graupner Terry System
A Multi-Item Review by Pat Mattes

Pat reviews the full Hobby Lobby recommended package with the Terry, and comes away delighted by what he finds.

E-mail Contact: pat-ingrid-mattes(at)juno.com

 

It’s now January, but I think I just received a second chance at Christmas. More often than not, you tend to get the more "practical" gifts at this time of year, so it was a nice surprise getting a complete airplane package that would warm the heart of any hobbyist! Jim Martin of Hobby Lobby provided the E-Zone with an opportunity to review Graupner’s new "Terry" Speed 400 airplane, and he was kind enough to provide an all-encompassing package consisting of the plane, motor, controller, battery, and the radio. Special charging jack adaptors were provided (for use with the Graupner chargers), as well as even the epoxy required for assembly.

   

More than likely you’ll be most interested in the plane, so let me address the review on that one first. I’ll do a bit of a "reverse review" again, starting out with the finished plane and its performance, then going on to the assembly. I’ll also cover the Speed 400 Plus 6V motor system, CAM 6x3 folding prop, and the 6-cell 500AR pack, all by Graupner. Last but certainly not least in this review is the Hitec Focus 3 FM and Hitec 555 receiver combination. (Obviously no need to cover the 5 minute epoxy, I’m sure you know what it is and how to use it….!)

 

Graupner "Terry"

As I reviewed this plane, I was wondering what criteria I should use as a baseline for its performance evaluation. There are several baselines to choose from, and mine will obviously be different than the next person’s, and the next person’s from there. So, I figured I would review performance two ways: First, how does the plane compare to its advertised performance? Secondly, how does the plane compare to my own expectations?

Hobby Lobby’s web-site (http://www.hobby-lobby.com) has the following advertisement on the Terry, denoted in bold italic text: I’ll use that as a starting point.

HL - The best RC flying you ever had -- about two hours after you get the box!

Yes, that’s true! I didn’t time the construction, but I was making notes and taking digital photographs along with construction and the entire project didn’t take much time at all (performing assembly on a second kit could probably be accomplished in an hour).

HL - 41" wingspan, 32" long, 265 sq. in. wing area, about 19 oz. flying weight, injection molded foam airplane that is a spectacular performer and very easy to fly.

Totally agreed. And obviously can’t argue too much about the dimensions given! The final weight was right on the money: mine weighed 19 oz. And I found the overall performance very good. Easy to fly? Definitely - it feels and acts very smooth, and responds nicely to input from the transmitter. I could lock it into a low altitude circle, and keep it there without any effort. Being a relatively light airplane, I felt it handled smaller wind gusts reasonably well. Bigger gusts would move it around somewhat, but that’s no different than any other plane this size and weight.

HL - Great aerobatics, parkflyer-speed landings, very easy to handlaunch (simply toss, don’t run — it’s powerful and goes right up).

The aerobatics were good; I could easily do loops from level flight on the 6-cell pack provided. I performed rudder rolls, and they were as good as with any other rudder/elevator-only craft I’ve flown. There’s still no substitute for obtaining a clean, axial roll like ailerons, but the rudder roll was a decent enough approximation... and easy to accomplish. Some rudder/elevator airplanes will get halfway through the roll and then find it difficult to finish the second 180 degrees, but I had no such problem with the Terry. Inverted flight was also very easy, and doing outside loops from level flight was a charm! It went into them and exited like it was on rails.

Parkflyer-speed landings? Oh yea, that and more! I spent several entire flights at "parkflyer speeds" and below. The Terry is well behaved at low speed; I was flying 2 feet off the ground in a 20 foot diameter circle at times, dragging the end of the antenna wire through the snow while I flew. Very predictable, very stable, and the ability to immediately power up and head out as needed. Landings were slow and sure, and I was even tempted to hand-catch it on occasion. That’s not exactly a good habit to get into; it’s usually advisable to land at your feet and impress your flying buddies that way… Remember that it weighs 19 ounces, so that’s still a fair amount of kinetic energy coming at you.

The only item I would make clarification on is the hand launch. The Terry fits your hand well, and is easy to grip. It’s light enough for a standing throw and well behaved once it’s on its way. But, I was a little surprised on the first couple of launches by a tendency to nose towards the ground after leaving my hand. In flight, the Terry has a fantastic motor-on/motor off pitch behavior. There basically WAS NO pitch change when power was added or taken away. This is nice! To accomplish that, the motor incidence is angled down to a point where some of the available thrust counteracts the increased lifting power of the wing at higher speeds. This makes for a very enjoyable flight, because you are not monkeying around with trim changes as you change throttle settings. But if you just casually launch a plane configured this way at full throttle, it could pitch downward a bit until flight speed is accomplished.

Just for kicks, I measured the motor incidence, and it was 5 degrees negative relative to the fuselage reference line. The wing was a positive 1.8 degrees relative to the fuselage reference line, which puts the motor at a total of 6.8 degrees downthrust relative to the chord line of the wing. This is enough of an angle to explain my first two launches, and if you do the math you’ll see that nearly a full ounce of thrust is being directed downward at full throttle (assuming 8 oz thrust – per Motocalc). This setting works well in flight, and I was pleased to see this effect occur while I was flying. But just be aware of it on your first launch. I would recommend a little bit of up-elevator trim for launch, or even do your test launches at less than full throttle until you adjust your throw a bit. I tend to launch towards the horizon, seldom launching at an upward angle. If you’re already the type that throws as much "up" as you do "out", then you may not even notice this.

HL - Terry is a very low drag airplane with a NACA 009 airfoil, and has more intelligent aerodynamic engineering than anything we’ve seen. Example: we watched it do a very large loop, power cut at top of loop, then continue the loop in a glide and then do a SECOND loop on the same flight path — without power! An airplane has to be very special to do that! 3-channel control: Rudder, Elevator, and Throttle.

The Terry is rather "shark looking", a term that is often used to explain aerodynamic sleekness (or hydrodynamic sleekness for you technical purists!). Sharks glide through the water thanks to nice clean lines, smooth radii, and good curve transitions, all of which contribute to flight efficiency. Not having the means to calculate efficiency or evaluate the aerodynamic factors, I was left with trying to duplicate the above statement. I couldn’t accomplish the second loop by keeping the elevator in the same position, but I did accomplish it with a minor amount of elevator change. Better yet, I managed no less than 4 consecutive loops without power, all it took was lengthening the back side of the previous loop by a little bit. I allowed it to dive a bit more on the back side, then pulled it into the next loop. You could do this all day with enough altitude; the point I’m making is that the 4 loops were all made within a respectably short altitude change. Obviously a true sailplane demonstrates the pinnacle of efficiency, but as far as a foam airplane goes I would say the engineering behind the Terry does make it rather efficient.

HL - Rudder and Elevator are pre-hinged, pushrods are hidden in the tailpiece slot in the fuselage. Servo locations are push-in cavities in the fuselage.

Very little work is required on the rudder and elevator. The foam is relieved (during molding) to allow the proper amount of control throw, and the actual "hinging" is accomplished by the decals. They adhere well, allow easy servo actuation, and are robust enough to let me fly with confidence. The pushrods are well hidden; the elevator pushrod is probably 99% invisible with just a hint of it exiting the rear of the fuselage. The rudder pushrod is about 90% hidden, and what little can be seen is routed through a channel provided in the fin and dorsal piece. Very little impinges into the airstream.

The servo pockets provided in the fuselage fit the HS-55 servos like gloves. So much so, that I nearly forgot to secure them in! A touch of epoxy is all that’s needed to keep them in place, and it is a step you would not want to forget.

HL - Fast assembly: servos and receiver simply get pushed into foam slots, held with epoxy glue

There is an addendum provided in the instructions when using the Hitec 555 receiver. It has an alternate placement than suggested, but the new location works out very well (see Assembly for more detail).

HL - Terry can maneuver in tight spaces then it can go all out for high speed flight when you want it.

As mentioned before, I was flying it low and slow and having a blast with it. Smooth and predictable at low speeds, with very good stall behavior. At higher speeds, it tracks very well and doesn’t "hunt" for a flight path. "High-speed flight" is a relative term, and since I have no way to measure speed I can only estimate it using a motor prediction program. Using the supplied motor and 6-cell battery pack, I modeled the power package in Motocalc and predicted a 35 mph top speed in level flight. And I’m sure I was reaching a LOT faster than that in shallow and "not so shallow" dives, and wouldn’t complain about it’s speed. The Terry is no 400-class pylon racer, but it wasn’t meant to be. It’s the perfect size Speed-400 airplane for "grab and go" flying. It flies well slow, and flies well fast. Interestingly enough, I was surprised by the performance I saw on just 6 cells. In a world where 7 cells was considered the norm and so many people are now moving out of the "7 cell trap" and going with 8 cell packages for more power, I was reluctant to even try it at 6 cells. However, the climb was rather good, flight speed was just right for sport flying, and by keeping current draw to 10 amps (less in flight) the flight times were enjoyable.

 

Now, let’s get into my PERSONAL expectations…

When I found out I was going to get a chance to review this plane, I was pleased. It fits a niche in my collection of electrics that is currently void. I’ve recently been playing around with 4-6 ounce slow-flyers, and in the past have dabbled at high-cell-count large aircraft. But, my favorite class of motors is and always has been the 400 class. I have some 400 class gliders, an "old-timer", and even a twin 400 plane, but I was lacking a good "grab-and-go" 400-sized sport ship. The Terry certainly looked like a perfect match.

So, what are my personal criteria? First off, the only airplanes that enter my shop these days are ones that are Almost Ready to Fly (ARF’s). I simply don’t have time or the patience anymore to build something flyable out of balsa sticks and iron-on covering. Secondly, nothing gripes me more than having an electric plane where battery changing is a major undertaking. If it takes more than 30 seconds, it’s downright annoying. Thirty seconds may seem short, but count it out once! (And then do it 6 times in a row on the same airplane). When I do get a chance to fly, I want to FLY, not wrestle with hold-down bolts, rubber bands, and goofy battery logistics. Thirdly, when I’m finished for the day, storage of planes in my basement "hangar" dictate a removable wing at the very least.

To my first point, the Terry gets an A+ for the "box-to-basement-to-back-yard" time. It was done quickly, and had I not been taking pictures and scribbling notes for this review, I could have flown it the very day I got it. I should have counted up the time spent, but I would agree with their 2-hour statement on assembly. To my second point, I’m not sure how battery change-out could get much simpler. You lift the canopy, and the battery is easily accessible and slides right out. Changing batteries only takes 10 seconds, and that’s on a cold day when my fingers are numb!

To my third point above, the Terry has two nylon bolts that hold the wing on. But wait, there’s more… The bolts run through special aluminum inserts, which not only protect the foam from the screw threads, but also provide a broad base on top to prevent the screwdriver from slipping off and poking the foam (as well as extra structure for the foam). Additionally, the nylon bolts go into nylon receptacles, so friction is an absolute minimum. Bolt to receptacle alignment is fantastic, so there is no binding during wing attachment. And a real bonus is that the stabilizer is removable as well.

 

Just a single nylon screw, slip the control horn off the wire, and the Terry goes back into its original box! Which, by the way, has a nifty little carry-handle built into it…

As far as actual FLIGHT performance criteria are concerned, I’m well aware of the range of performance of Speed 400 motor systems, so I pretty much know what to expect. A direct drive system narrows the performance range even further, taking out the variables associated with gear ratios and prop sizes. With that in mind I was only concerned that the Terry would be properly matched for this power combo. Additionally, I didn’t want any surprises or quirks to show up in flight, like tip stalls, loss of control authority at low speeds, or otherwise "bad behavior".

To address the flight criteria, I offer the following: the Terry was well matched with the Speed 400 Plus system, it has enough power to climb out well, achieved a fair top speed on 6 cells, and had good duration. I tried 7 cell and 8 cell packs and the climb rate and top speed increased, as one would expect. Climb rate improved more than top speed, but this is due primarily to using a relatively low-pitch prop. With the CAM 6x3 folding prop used, the 2700 rpm increase going from 6 to 8 cells only resulted in about a 5-8 mph change in top end, although providing nearly 25-30% increase in output power. So yes, the power increased and you could see it in the climb, but top speed didn’t rise as proportionately. A higher pitch prop would increase top speed a bunch, but it’s hard to find smaller diameter props that will still fold. The 7 and 8 cell packs moved the CG forward, and there is no way to avoid this totally. A specially fitted battery pack would work if you modified the front fuselage former, but in the stock configuration the Terry gets a little nose heavy with more than 6 cells. It flies well this way and adds no strange behaviors other than reduced sensitivity in the elevator. It’s a very fun, relaxing airplane on 6 cells, so I’m going to leave mine right there as far as power.

And finally my last criteria from above, "bad behavior"… The Terry is well behaved. I haven’t found a bad habit yet!

 

Assembly

Now we get back to where we started, by opening the box. There’s little to assemble, and what hardware is needed is clearly marked. Assembly is simple, but refer to the instructions provided and read through them carefully. The instructions were good, but did miss a few elements I thought were important. I’ll point them out specifically as I get to each section. (These are not in order)

Foam part preparation

A little bit of foam flashing exists on the parts, so either sand them carefully or trim them off with a sharp hobby knife.

Wing

Construction involves adding two aluminum inserts into the wing, and adding decals. Taadaa! It’s done.

Stabilizer

The elevator is partially separated from the stabilizer by cutting two short slots at each end. An aluminum insert similar to the ones used in the wing is added to the stabilizer, and a locating block is epoxied on. Add the decal, flex the remaining foam in the hinge, glue in the control horn and you’re done here too.

Fin

The rudder is hinged the same way, through the use of the decals. Final assembly goes hand-in-hand with fuselage work, so refer to that section for the remainder.

Fuselage

Here is where the bulk of the work needs to be done, what little there is! An internal foam section is cut away and the Speed 400 Plus motor system is pushed in through the front. If you are NOT using the Plus system or similar type of motor-attached controller, this step may not be necessary. Check it out and make your own evaluation, though. The hatch components are glued in, and the main former (Item #4) is constructed and glued into place.

NOTE: Here’s where you need to be careful. There was a note to size the former, but they didn’t say how. Later on I realized the laminated former needed substantial trimming at the bottom edge to clear the battery! It was laborious work trying to make clearance. Make sure you put the battery in and double-check the former fit. I had done side-to-side trimming to make it a drop-in fit, but hadn’t thought about battery clearance. The side angles in the picture are exaggerated due to the lens, but you can see I needed to clear out about ¼" of double-thickness light ply that had been laminated together. Plan ahead, save some work!

Next, the stabilizer T-nut is prepped and glued in place, the fuselage stiffener added, cables are positioned, trimmed, and glued in place, and finally the fin/dorsal are glued into place. The running of cables, insertion of control horns and securing in place should be well planned out. I used 3M77 adhesive spray to "tack" everything where I thought it should be. After dropping the servos in, I did a trial check of movements and made some minor adjustments, which was easy enough to do since they were only tacked into place. These are simple enough steps, but don’t run too fast through it. If you do it wrong, you’re talking a LOT of rework to make it right. Proceed slowly…

NOTE: I did find it necessary to trim some foam from the bottom rear of the fin assembly. More for convenience than necessity, but I needed a bit more clearance for the elevator cable to give it smoother bends. Again, trial-fit everything in these steps and use tape to hold things in place. Once satisfied, add glue and commit yourself to what you’ve done!

If you haven’t already applied the decals, the remaining ones go on now. A nose decal on the underside serves to protect the foam, but if you are planning on landing in rough areas I’d recommend a few extra thicknesses of tape. Another decal protects the receiver antenna, which is routed along the bottom side of the fuselage. Once your Terry is pretty enough for you, mount the wing and place the hook-and-loop fastener pieces in place for canopy retention. You might want to add tape to the tail skid as well.

NOTE: There are mold-vent protrusions on all the foam parts. If you add decals over them, they could appear lumpy. Take the time to visualize where the decals will go, then lightly sand the bumps down in that area so the decal will lay flat. I didn’t do this for the first couple of decals, and should have. Once I did this though, the decals laid nice and flat and looked great. I have a foam-backed sanding pad (foam rubber) with very fine grit, which works great for sanding styrofoam.

NOTE: The instruction addendum specifies locating the receiver right behind the front former, rather than behind the two servos. If you’re using a small receiver, stay with the rear location. As small as the 555 receiver is though, it still needed to be moved behind the front former. A simple balsa shelf keeps the receiver away from the battery.

 

Add the battery, balance the plane, check all your equipment and then go range check. It might be prudent to put a piece of foam between the battery and speed controller, just in case you do a vertical landing accidentally… nose first.

Have someone hold the plane for you so you can range check with the motor running. Half-throttle is usually sufficient to determine if there is any radio noise being generated by the motor.

Now go fly!

 

Speed 400 Plus 6V Power System

The integrated speed controller and motor is a neat idea. You open the box, place the motor, hook up the connector and you’re done. It doesn’t get much simpler. Sure, I don’t mind grabbing the soldering iron and making a few connections here and there, but for someone who doesn’t have soldering know-how or doesn’t like flux fumes, then this is your ticket.

I am by no means an electronics expert, but I know what most of the little parts do on a controller. There is no casing, so it was easy to look at the components and identify them. Sorry about the focus, that’s the best I could do close-up with my camera.

 

This is a Brake and BEC (battery eliminator circuitry) controller, with current-load specs of 15 amps brief and 20 amps spike. Armed with this information - and squinting because the parts are so small - I rationalized that two of the 8-legged chips I call Spider Chips (technically called S08 chassis) would be the Drive FETs and one of them a Brake FET. The larger component in the middle with its back to us would be the BEC voltage regulator.

The spider chips are usually good for 7-8 amps of continuous draw, and two in parallel would achieve the maximum current specified without a problem. The same assumption would be you’d get 8 amps of Brake power out of the third spider, but I don’t think it’s that easy. I won’t conjecture on the voltage regulator, but the specs say 1.5 amp capability. Further detailing the BEC capability, the specs say that you can run 3 servos when using 6-8 cells. (If you buy the 7.2 volt Plus system, you can run 3 servos up to 9 cells and 2 servos at 10 cells. Servo load needs to decrease as pack voltage increases).

Interestingly enough, I picked up something while double-checking the specs that I didn’t even notice in my flight analysis. First off, the Brake will only kick on for 5 seconds then it will let the motor free-wheel. It seldom takes more than 1-2 seconds for a folding prop to stop and fold back, so this is more than adequate time. This 5-second limit protects the controller from overheating in Brake mode if you happen to be in a dive at the time, or if you are using a fixed prop. In a dive a folding prop will NOT fold - centrifugal force always wins over wind drag – and you’d be trying to back-feed the controller with voltage. Same goes for a fixed prop, so this is a good feature to have. Secondly, the motor will switch off if the current exceeds 20 amps. This is another good feature to have that avoids burning up speed controllers. However, I wouldn’t recommend running up against this limit just for kicks, it’s hard on Drive FET’s. Both of these are nice features of the controller that will help keep you from ruining your flying day.

The controller operation is simple enough. Once your transmitter is turned on and you connect the flight battery, a beep signifies the transmitter and speed controller are communicating. The controller will beep whether your throttle stick is set to idle or full, but if the throttle is set to full the motor will not come on when you move the stick. A rather nice safety feature. If this happens, you only have to disconnect the flight battery, put the throttle to an idle position (or reverse your throttle channel at the radio if you set it up wrong), then re-energize the system. It’s a self-ranging system, meaning that it automatically detects off and full throttle positions and requires no special setup or consideration. It also has the standard "radio priority" feature that will shut the motor off before it drains the flight battery too far down to power the receiver and servos.

In flight, the performance of the controller and motor was flawless.

 

CAM 6x3 folding prop

The 6x3 is a good match for the Terry. The CAM prop blades are more efficient than the less expensive gray 6x3 blades, and I can notice the difference in motor RPM any time I switch between the two sets. They are nice props and I’ve used them before, especially on faster 400-type airplanes where I still needed the ability to fold the prop. For use on the Terry, you would need to order the 40mm (1-1/2") spinner set, rather than the 30mm set (1-3/16") in order to match the nose diameter.

 

6-cell 500AR battery pack

The battery pack provided with this review set was labeled 500AR.  These are the green-jacketed cells, which some believe to be inferior to the older red-jacketed cells, but this wasn't my experience with this pack. So what can you really say about a battery? It charged faultlessly, delivered great power in flight, and held its voltage taper off until the end of the pack. The 500AR’s have already proven their versatility in the field, and these certainly performed no differently.

 

Hitec Focus 3 FM Transmitter and 555 Receiver

The Hitec Focus series radio started out life as a single stick 2-channel system. It was an inexpensive, light, and convenient radio that was easily held in one hand while you threw the plane with your other. (unfortunately a little awkward for Lefties!) It wasn’t long before people figured out how to do brain surgery on them and add the third channel to both transmitter and receiver. Of course shortly after that got popular, Hitec released the 3-channel variant, maintaining the single stick 2-channel operation and adding a third control on the back of the transmitter. The originals were AM frequency, and later on they released the Focus 3 radio in an FM version, alongside the miniscule 9 gram "Feather" receiver. The Feather receiver is a single conversion unit, intended for closer-in flying such as slow-fliers or indoor RC types. So when I received the Focus 3 FM transmitter and a Hitec 555 was in the box, I thought "Gee, why didn’t I think of that?" The Hitec 555’s performance and reliability are legendary, and I’ve heard nothing but positive about this receiver. Combining it with the handy little Hitec transmitter made it a perfect match! I performed range checks and had no jittering at all with either the 555 receiver or the 400 Plus integrated controller system. In flight, I had no problems either, just a crystal clear connection from me to the plane.

 

Final Analysis

The Terry is a quick assembling, well behaving airplane that is perfect for a "grab and go" model. It flies well, has a decent speed range, and allows you to bang out a bunch of flights in a row without hassle or delay. It’s fast enough as an everyday sport ship, and slows down well enough to do backyard flying too. The Hitec transmitter and receiver combination worked flawlessly, combining a handy little transmitter with a full range receiver. The Speed 400 Plus motor system made for a completely goof-proof setup, and provides enough flexibility to handle higher currents and voltages whenever anyone wants to upgrade a bit. The entire package was very well matched, and if you were going to buy a complete system then what’s listed above is just the ticket.