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Model Airplane Engineering TumbleBuddy Jr. Review
It's a plane! It's a UFO! No, it's Napo Monasterio's latest review! Join him as he takes this flat, almost-circular foamie out for a (flat) spin or two. It's a hovering machine if you ever saw one, so click on!
Introduction
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| Wingspan: | 22" |
| Wing Area: | 340 square inches |
| Weight: | 6-6.5 oz. (with 2S and 3S LiPo, respectively) |
| Length: | 24.5" |
| Wing Loading: | 2.5-2.75 oz/sq. ft. (with 2S and 3S LiPo, respectively) |
| Servos: | Three Tower Pro 6-gram servos |
| Transmitter: | Spektrum DX7SE |
| Receiver: | Spektrum AR6100 |
| Battery: | 2S 500mAh or 3S 500mAh LiPo (10C or greater) |
| Motor: | M-A-E "Slo-Fly" 25-turn outrunner brushless motor |
| ESC: | Castle Creations Thunderbird 9 brushless speed controller |
| Manufacturer: | Model Airplane Engineering |
| Available From: | Model Airplane Engineering |
| Price: | $34.95 (kit only) to $123.95/$129.95 (receiver-ready ARF with 2S or 3S LiPo, respectively) |
Folks at my flying field tend to say that I always bring (and I quote verbatim) "the most interesting stuff" to the flight line. I've brought tiny planes with huge wasp graphics across the wing, foamies big and small, even R/C-friendly applications for my iPod Touch. have set a standard for myself, whether I wanted to or not.
The quest at the Monasterio Electric Aerospace Institute and Crash Test Facility© (motto: "Electrons Rule, Yet Gravity Always Laughs Last"©) is always on, and this time the quest led me to a few pieces of Depron foam with plenty of personality. Meet the TumbleBuddy Jr., the UFO-looking creation of Georgia-based Model Airplane Engineering.
Kit Contents
It's always a good day when you open the front door and find a package with the words "Model Airplane" written on it. Upon opening it, here's what I found:
- Three pieces of 6mm Depron, with the 3mm Depron control surfaces already pre-hinged.
- Pushrod made of 1/32" piano wire.
- Several pieces of balsa wood and a couple of small, laser-cut ply sheets.
- Printed instructions.
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Tucked in the midst of paper and bubble wrap lies a small pile of foam. Give it 15 minutes, and that pile of foam will be a bonafide plane.
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Model Airplane Engineering has a new spin on hand-cut ARF foamies: All surfaces are pre-hinged, sure, but all the decals are installed, and there even are markings for servo placement.
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The elevons are pre-hinged. Now that's what I call the royal treatment, for you only need to add the included pushrods and control horns in order to have them ready to go.
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The motor mount and the control horns are the only non-foam parts of this kit.
Needless to say, the low parts count points to an low assembly time. However, if you want to be tumbling around, you'll need a few more parts. Here's what I used:
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Motor: I used the recommended M-A-E brushless motor, courtesy of Model Airplane Engineering (it's custom-made for the company). For props, I received GWS direct-drive 10x6 and 8x4 props, which one would use for the 2S or 3S system.
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Three servos: Any sub-micro servos will work, and I received some Tower Pro ones from Model Aircraft Engineering for this project.
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Speed controller: I plugged in a Thunderbird 9 brushless speed controller that Castle Creations provided for this review. (A Thunderbird 6 would work fine, too, since the maximum amp draw will be in the 5-amp range, anyway.)
- Batteries: You can either go with a 2S or 3S setup, and the ones I used were in the 450-500mAh range for each.
- Receiver: As I do with all my small planes, I put a Spektrum AR6100, which provides bulletproof performance with a minimum weight penalty.
- Tools of the trade: You'll need some glue, be it canopy glue, foam-safe CA or even contact cement (I used CA and a hot-glue gun along the way, but options abound). You'll also need a hobby blade, some hinge (or packing) tape and whatever other tools you may want. It is, after all, a project that will be beyond simple to complete.
Assembly
Motor mount
The first order of business involves getting the business end ready for the brushless powerhouse. All that needs to be done is to put the small piece of plywood that will hold the motor into the motor stick. There's no need to glue those yet. Then, glue the motor stick to the top of the wing, and secure it with the two flat pieces of balsa.
Wing and fuselage
OK, set your timers and... start! Grab the top of the fuselage, and cut a hole for the rudder servo. Glue the aforementioned top of the fuselage, and glue it to the wing. Grab the bottom of the fuselage, and glue it to the wing. Step back. Look at it. You're done.
Yes, folks, it's that easy. You now have a finished plane — sans electronics, but still something that resembles a plane.
You do need to apply some tape to hinge the rudder at the bottom of the fuselage, but the rest of the control surfaces are pre-hinged and ready for instant gratification.
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Trace, cut, move on. It's that easy to carve out a hole for the rudder servo — even the location is marked for you.
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A few drops of glue, and your two-dimensional wing just became a bit more three-dimensional.
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A couple of small pieces of hinge or clear packing tape will keep the rudder safely attached to the bottom of the fuselage.
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Blink and you might miss it: That's how quickly the TumbleBuddy Jr. goes together. Next up: Electronics installation.
Radio Installation
This is where the real work begins — if you can call it that.
Let's start with the servos (which you should center before gluing): Grab the rudder servo, and glue it to the fuselage and wing. I used some foam-safe CA to secure them in place, then a few squirts with the hot-glue gun for a little more security. The elevon servos are even easier to install, by simply laying them flat on the wing (don't do like I did the first time around and set them upright — not a good idea).
While we're in the vicinity the control surfaces, add the plywood control horns to each of the control surfaces, and then cut some of the piano wire for the pushrods. You can attach them via z-bends on both ends, but I went the precise/lazy way and put some Du-Bro mini connectors on the servos, which made it ultimately easier to adjust.
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"Why it pays to think first, Exhibit A." Had I used common sense, I would not have glued the elevon servos this way...
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... but rather this other way. Oh well, we live and we learn. And, after all, it's just foam and glue, right?
The motor is a simple installation, and all that needs to be done is to slide the carbon-fiber motor bearing tube into the ply pieces you already installed, then use CA to set it in place. Per M-A-E's recommendation, I also put a small strip of scrap ply between the ply motor-mount pieces to prevent them from sliding up and down too much. And for an extra dose of peace of mind, I went ahead and added a small screw than went all the way into the motor bearing tube. This thing is not going anywhere any time soon.
The rest of the electronics fall into place below the wing and in a simple fashion. Both the speed controller and the battery go at the very front of the fuselage, while the receiver went as far forward as the servo wires would allow (I did have to use a small extension for the rudder servo, but that was it.)
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The motor slides into the motor mount without a problem, and a few drops of CA glue set it in place. For a bit of added insurance, I placed a screw all the way through. Now, I have no fear of a runaway motor.
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All the electronics tuck nicely underneath the plane — receiver and speed controller on one side, battery on the other.
Completion
In record time, even by my standards, I had a plane. It can be put together in a short evening without a doubt, so it's an easy project that provides a nice distraction from those other more time-intensive endeavors.
There's not much to setting up your radio. You do need to set up the tail surfaces as a delta wing (or else get a mixer y-harness for it), and that means that when moved individually, the surfaces would move like regular ailerons and elevators. Together, however, they work in unison.
When it comes to travel rates, more is better according to the instructions. Set each control surface for as much deflection as you can, and then add a huge amount of expo (read: 70 percent or more) to tame this foam beast down.
So, in the time that it took us to build this plane, the batteries should be charged. What are we waiting for, people?
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Say, is this a quick build or what? If you have a free evening without much distraction, you could be maidening it the next morning — or that same night in between the parking-lot lights.
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It's a junior plane all right, and a light one as well. With a wing loading of 2.5 ounces per square foot, it should float along nicely yet have enough power for some mad aerobatics.
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Throw enough for ya? I figured so. And, if you can get even more from it, by all means add it. More, in this case, is better.
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It's a simple plane, but it has plenty of personality, and it advertises itself as a versatile flyer. We'll see what happens.
Flying
Measuring all of 22 inches in wingspan (or circumference, for that matter), there's little doubt that you'd need a big open field to fly the TumbleBuddy Jr.. A large backyard would do, and so would a soccer field or the park down the street. I take it to my club often, but it's also a fine aircraft to toss around behind the house in the evenings, too.
Taking off and landing, er, hand-catching
In the absence of landing gear, a quick toss is the de facto way to go with this plane. With a good amount of throttle, maybe two-thirds to three-quarters, give it a quick underhanded toss, and the plane will just take off without much effort. Be sure to get back to the sticks in short order.
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Grab the top of the fuselage, give it some throttle...
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... and let the madness begin. Now that wasn't that hard, now was it?
When it comes to returning the TumbleBuddy Jr. back to you, things can get a lot more exciting. The preferred method — and certainly the most entertaining one — involves a hand-catch. Sounds fun, sounds exotic, sounds simple, and it can be all of those, but it can also be a royal challenge, especially in the wind.
The best way is to set yourself up in a harrier, preferably into the wind, then slowly bring it toward you. Once you're within reach, go out and grab it. You don't need to be an NFL-grade wide receiver for this task, but it does require some quick reflexes.
I probably have a .500 average on this plane when it comes to grabbing it in the air, but if you don't want to catch it, that's fine as well — just slowly glide it into the grass. But don't nose it in, for the balsa motor mount is as brittle as I expected it would be. It can be repaired on the field with some CA and scrap ply, but it can be prone to snapping if you miss the catch and, say, hit yourself in the shin with it (not that I would know anything about that particular maneuver).
Basics
This plane looks fun, and in the air it's equally fun.
It took me by surprise that even though the control surfaces moved roughly a country mile in each direction, it was not as twitchy as I expected it to be. Sure, the 75 percent expo does help, but since the plane flies so relatively slowly, it requires a vast amount of travel so there's no need for low rates. Keep it as recommended, and you'll be in business. (A bit of down elevator was needed for straight flight, but it was simple to trim other than that).
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The good thing about the TumbleBuddy Jr. is that it can be flown in close quarters, making it an ideal backyard plane — or even a nice indoor one, if you have the right venue.
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Are you the kind of person that likes to get low and slow with your aircraft? So am I, and even though Depron is no EPP, it still is relatively durable in case of a, um, mishap.
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Where's Waldo, er, Junior? It's a squirrely little aircraft, and it likes to hide, apparently.
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Come back here, Buddy! (If you can in fact tell me what I'm supposed to be doing here, I would be much obliged.)
Needless to say, a plane with so much wing area, swinging such a big prop that’s so light only means one thing: Slow and floaty. When handled with care, it moves along rather gently, harriering its way past you at crawling speeds. You would think that it's the epitome of a calming flyer, but...
... you would be beyond mistaken. As soon as you crank up the throttle or smash on the sticks a bit, it becomes a lean, mean, aerobatic machine.
Aerobatics/special flight performance
The TumbleBuddy Jr. might seem relaxing, but it is a master of deception. It’s a four-channel plane, and it can pull just about any maneuver that any other plane could — it may do them better, or it might fall awfully short, but it will attempt to, anyway. Here are some of the ones I put to the test as well as how each one of them fared.
- Loops: Tight or big, outside or inside, it does them all, and it does them with style. There's not a lot of rudder input that's necessary to keep them nice and straight, and that's a plus.
- Rolls: Just like the loops, you can get them in any flavor you want. But if your preference is a mad roll rate, you came to the right place. The TumbleBuddy Jr. can roll like the best of them. It's a hoot to go up and down the field with it this way.
- Harriers: Given the fact that this plane is slow yet has plenty of thrust, it's no surprise that it harriers quite well. It locks in relatively easy, though it might want to stall out every now and then. A careful elevator/throttle dance must be played to keep it in place.
- Inverted harriers: I'm not sure why, but these were even easier to perform than the upright ones. Once I locked in, I was set in place for the duration of the flight, often ending the fun with a nice little outside loop. On the other hand, inverted flight can be a bit treacherous at times, as the plane likes to point its nose up. It is manageable, however, as the video shows, t just requires a bit of getting used to in the down-elevator department.
- Knife edge flight: Believe it or not, the TumbleBuddy Jr. can get on its side and move along. It's not pretty by any means, but it certainly is doable. There's a lot of elevator coupling that's needed (not an easy feat when you have elevons and a limited amount of fuselage), but you can somewhat accomplish it. It might look like an inebriated pilot is behind the sticks, but at least you can say you tried it.
- Waterfalls: This aggressive variation of the outside loop is also part of the repertoire, and there's little rudder input required to keep it nice and axial. Be sure to put an extra O-ring on the prop saver or otherwise you might losing power in short order (been there, done that).
- Rocking chairs: They're not as relaxing as the name might imply, but they sure are exciting. By killing the throttle way up high, then going into a full-down-elevator, full-up-elevator routine, the plane descends nicely and without any awkward tendencies.
- Spins, flat spins and inverted spins: They are nothing short of a hoot to do, especially the latter. The plane just floats along nicely on a gravity-bound wide circle, though plenty of elevator and a hint of throttle must be applied all along the way in order to keep those flat spins, well, flat.
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Harriers, you say? Done! They're some of the easiest ones to perform, even in mild winds. Inverted ones are easily feasible
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Flying inverted, or in the middle of a flat spin? You be the judge. Either way, both maneuvers are easily accomplished.
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Waterfalls are nice and precise with this plane, and a minimal amount of rudder is required to keep them nice and axial. Other than that, they're equally impressive and aggressive.
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Knife-edge flight may end up being a bit of an exercise in futility with an elevon-equipped plane — but, even if it's not the prettiest thing you've ever seen, it's still part of the repertoire.
These were some of the fun maneuvers, but in the spirit of saving the best for last, here were my three favorites. I am not a 3D pilot extraordinaire by any means, but this plane made me look better than I truly am:
- Rolling circles: Surprisingly enough, once you get in the groove of doing them, the TumbleBuddy Jr. stays on a pattern and doesn't stray. It's not as hard to do as it would be with any other plane, and that's something I appreciate.
- Hovering: The huge amount of thrust coming out of the motor allows it to hang on the prop like a champ. It's extremely stable once you lock in, and it's easy to keep it in one spot without much fanfare. It’s maneuver I wish I could replicate with many of my other aircraft.
- Torque rolls: This is, by far, the pièce de résistance on this plane. Once you lock into a hover, just a minute amount of aileron input will get the TumbleBuddy Jr. spinning in one spot like there is no tomorrow. This is one maneuver I can hardly perform on some other 3D planes, but in the case of this plane, you could almost say it's harder to get out of a torque roll than it is to get into one.
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Low to the ground and pointing straight up — that's the way to hover and torque-roll. The TumbleBuddy Jr. does both in an amazing fashion.
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Harriering with the 3S power system is not as slow as with the 2S battery and 10-inch prop, but that doesn't mean that you can't still do them up and down the flight line.
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If you're not the hovering kind, be forewarned: You soon will be. This plane makes it look easy, and for that I am grateful.
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Torque-rolling is a piece of cake with the TumbleBuddy Jr. — take it from someone who can hardly get a couple of revolutions with any other of his planes.
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How close can you get, both to the pilot and to terra firma? Surprisingly close, indeed. It's fun to hover it in front of you, and that's a past-time that I in fact prefer with the 3S power system.
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Close-to-the-ground rolling circles? Check. They're fun as anything to perform, and the responsiveness of the control surfaces makes them even more exciting to do.
2S or 3S — that is the question
So, there's an option to going with a two-cell LiPo or a three-cell LiPo. And, if the 2S option is fun, does that mean that going 3S would make this fun-and-a-half?
That might come down to personal preference.
Using a 2S battery and 10x6 prop, I had more than enough power to do everything I needed it to do. I could perform outside loops like the best of them, and I could do anything I wanted to it as well. It had plenty of thrust, and it flew nice and slow. More important, it felt floaty, and in my book, lighter is better.
Popping a 3S battery and propping down to an 8x4, you can certainly tell the difference, but it's not as drastic as one would think. The thrust is still there, and what you really get out of is a bit more punch and a touch more speed out of it. But, even with that extra power, it's not like I felt like a completely different aircraft. In fact, the thing I noticed was that it didn't feel as light as it was — a whopping .4 ounces heavier, in fact, and in a model this small and light, you can tell the difference in the air.
One thing I did appreciate out of the 3S power system is that you can have a lot more fun in the low-and-slow hovering department. With this setup, it was a hoot to do tail touches, get up close and personal with the plane and do all sorts of other crazy maneuvers while hugging the grass. The extra punch helps in that regard — and it will certainly help as well when trying to recover.
So, 2S or 3S? Again, it all depends on your style of flying, but I lean toward the two-cell option. Lighter, equally powerful, slower — and, ultimately, a bit cheaper as well. Flight times will not be all that different, anyway, as you can get a bit more than 10 minutes out of either pack.
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There's not much difference in flight time between the 2S and 3S power systems. Both of them will allow for more than 10 minutes of in-your-face tumbles and harriers.
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There's plenty of vertical performance coming out of the 2S power system. It will hang on its nose, and it will climb vertical without a hitch.
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Catch me if you can: With a 3S power system, there is a bit more added power to this plane — and, judging from this "I'm getting out of your frame" photo, you can tell it zips along quite well.
Is this for a beginner?
Despite its lightness and floaty characteristics, this is still an aerobatic plane. And, while made of foam, Depron is not the most crash-resistant of materials either. Those two factors don't mix well with first-time pilots.
It is an extremely easy build and would make a perfect first kit for someone who has already logged a few hours with an aileron trainer. It would, in fact, be a good 3D trainer thanks to how easily it performs a lot of those kinds of maneuvers.
Flight videos
Downloads
Downloads
Conclusion
Don't get me wrong: I love a proven aerobatic machine or a sleek fighter jet or a World War I replica as much as the guy next door, but it's unusual projects that do stick with you — and folks at the field, apparently. Add to that equal doses of backyard performance and ease of building, and you might agree that we have something going here.
I would like to thank the following for making this review possible: Randy Roman at Model Airplane Engineering for providing the kit, motor, servos and props for the review; Castle Creations for providing the Thunderbird speed controller; and my friends Michael Wieczorek, Chris Giles and Bo Lovell for some amazing footage and photos.
The TumbleBuddy Jr. passes the rigorous test here at the Monasterio Electric Aerospace Institute and Crash Test Facility© (motto: "Electrons Rule, Yet Gravity Always Laughs Last"©). I made it from front door to flying field in less than 48 hours, and the fun that can be had with this unique aircraft is almost limitless. It does what every other plane does, but it does it in a completely different manner. It's a joy to fly — and the oohs and aahs will still prevail from the peanut gallery.
Pros:
- Simple, clever design.
- Quick to assemble.
- Fantastic flight performance — even I look good torque-rolling it.
- Possibility of flying it with 2S or 3S power system is a nice option.
- Fun-per-dollar ratio is quite good.
Cons:
- Balsa motor-mount positioning and design can make it prone to breaking a bit too soon. (Then again, it's cheaper and easier to repair or replace the motor mount than to purchase a new motor altogether.)
Last edited by Spackles94; Sep 04, 2009 at 10:41 AM..
Discussion
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Sep 04, 2009, 10:59 AM
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Birmingham, Alabama
Joined Feb 2007
7,869 Posts
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Here are the files in Vimeo format, in case any of y'all can't open the .mov files (with Quicktime).
Tumblebuddy Jr. on 2S.
Tumblebuddy Jr. on 3S.
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Sep 04, 2009, 11:26 AM
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About 15 miles from Bristow, OK
Joined May 2009
648 Posts
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Nice Review.
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Sep 04, 2009, 11:51 AM
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Joined Jan 2009
7,567 Posts
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Great review, Spackles. Thanks.
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Sep 04, 2009, 12:37 PM
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USA, AL, Athens
Joined Jun 2003
4,262 Posts
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Nice one Napo! Love the pictures and videos!!!!
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Sep 04, 2009, 12:54 PM
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Joined Oct 2007
20,465 Posts
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Looks like FUN
NICE review, as usual 
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Sep 04, 2009, 01:45 PM
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Birmingham, Alabama
Joined Feb 2007
7,869 Posts
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Thanks guys! It is, indeed, a very fun plane. I don't usually get that low with most of my planes to begin with.
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Sep 04, 2009, 06:24 PM
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Lilburn, GA, USA
Joined Dec 2000
1,148 Posts
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I'd like to express my personal thanks to Napo and Angela for their efforts in putting together this most excellent review! Also... many thanks to Ken Daughtry for the original design.
 FWIW... both the plane and motor are manufactured right here in our shop. Accordingly, we provide complete support for technical assistance, repairs, and replacement parts for all of our American-made products. Here is a LINK to an earlier Ezone review of our SLICK ... now in its 5th year of sales. You can also find links to some of our other models in the "Similar Threads" section further down this page. Randy Model Airplane Engineering www.m-a-e.com |
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Last edited by rcflyer11; Sep 12, 2009 at 01:08 PM.
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Sep 04, 2009, 06:47 PM
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Tanner, Alabama
Joined Oct 2003
6,063 Posts
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Napo, your reviews consistently raise the bar when it comes to pictures. It is always a treat to see what kind of photographic goodness you bring us each time. Oh, the article wasn't bad either, but I really dig the pics!
 Now when are you gonna let me fly this plane? It looks like a hoot! Andy |
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Sep 04, 2009, 07:21 PM
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USA, TX, Trophy Club
Joined May 2002
12,977 Posts
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Hmmmm Looks like a fun one - great review Napo!
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Sep 05, 2009, 11:02 AM
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United States, CO, Boulder
Joined Sep 2008
7,426 Posts
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Love the review Napo!
I really like your subtle humor throughout the whole thing- it really makes the review fun to read. You pictures are awesome too- as always. -Kevin |
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Sep 09, 2009, 02:18 PM
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BIRMINGHAM ALABAMA
Joined Jan 2006
1,451 Posts
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Awesome...
Napo, as usual, another great summation. I'm glad some of the time-lapse photography of the plane catch made it into the final cut. And the video was the most fun I've had filming and flying in a long time. I've got to get one of these before the JR indoor. Let's fly monday if we can.
Bo |
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Sep 09, 2009, 05:57 PM
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Birmingham, Alabama
Joined Feb 2007
7,869 Posts
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Hey guys, thanks for the kind words. Glad y'all enjoyed it! The TB sure is a keeper. I was flying it on 2S around the backyard yesterday, in fact. With the tamer setup, I can't get enough of it on the small spaces.
Yeah Bo, we had a good time indeed. Thanks for all your help! I'll give you a holler about going to fly on Monday then. |
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Sep 09, 2009, 06:59 PM
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Jasper, TN
Joined May 2004
1,149 Posts
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Hey Napo ! great review. looks like a fun little plane. maybe you can bring it up to Tanner sometime soon?
Brian |
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Sep 09, 2009, 08:51 PM
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Birmingham, Alabama
Joined Feb 2007
7,869 Posts
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Quote:
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