Text: Pierre Rondel / Photos: Pierre Rondel / Joël Marin
Introduction
This time we can say that Michael Richter, the designer of the now-famous Alula and the no less popular Weasel, caught us somewhat by surprise, revealing only very late one or two detail photos of the future kit that was to be released a few weeks later. This only heightened the excitement when we realized that it was a small VTPR glider (Very Close-to-Terrain Aerobatics), with a 1.20 m wingspan and low weight, therefore capable of flying in light conditions.
It is amusing to note that the very first EPP VTPR glider, the Minitoon, designed in France by Jérôme Bobin and Thierry Platon, later gave rise to various versions and improvements all over the world—sometimes in EPP, sometimes even fully plastic—before finally returning to France more than ten years later, this time from California, in the form of a very refined kit. It is still foam, but now molded.
Today, I propose a test of this Ahi (the Hawaiian name for albacore tuna, also known as yellowfin tuna).
A complete kit… plus a few options
The Ahi kit arrives in a nicely decorated box that can later be used for storage or transport. Examining the kit components, accessories, and instruction manual once again shows the passion and care that went into the design and manufacturing. Assembly is highly advanced, following in the footsteps of the Weasel Trek and Alula Trek, even though a (very small) amount of work still remains.
The molding quality is first-rate, with finely molded details and clean, well-fitted assemblies. Starting with the fuselage, which comes pre-assembled, it already includes a square-section carbon spar installed in the rear boom to provide the necessary stiffness. A superb molded carbon canopy, extremely lightweight, fits perfectly. Attention to detail is evident: a small label protruding over the canopy edge warns the lucky owner about its sharp edges. The canopy is held in place by two powerful magnets, perfectly aligned in their housings.
Once the canopy is removed, a pre-glued plywood plate can be seen, contributing to the stiffness of the fuselage nose. The control sleeves for elevator and rudder are also already installed.
The wings are very light and feature large ailerons. They come with carbon strips on both upper and lower surfaces acting as spars. Another carbon strip inside the aileron stiffens it further. The plastic control horns are already glued in place. A very strong small magnet is glued at the wing root to secure the wings once assembled, in addition to the plastic insert and screw that clamp the wing joiner. The joiner itself is a rigid carbon tube.
Next comes the tailplane, also reinforced with a carbon strip and fitted with its control horn. The fin, which includes both fixed and movable parts, has no reinforcement but is also equipped with its control horn.
An accessory bag contains plastic clevises, aileron pushrods, a few screws, some transparent vinyl, and decals. Two carbon rods with Z-bent piano wire ends are also included, along with a small, very comprehensive assembly manual—still as well written as ever (although in English)—providing all the advice needed for assembly and setup, with plenty of photos and explanatory diagrams.
In short, while it cannot yet be called a ready-to-fly kit, it comes extremely close, as most tedious operations have already been completed, leaving mainly the radio installation.
As optional extras, you can also purchase the recommended Dream-Flight servos (digital with metal gears), servo extensions, a correctly sized 800 mAh NiMH battery, and ballast weights. All of this can save even more assembly time.
Ultra-fast assembly
The first step is painting, which is best done before installing or assembling anything. For once, this is the longest operation given how advanced the kit already is. I used special Elapor paint in fluorescent orange, along with “Blue Tape” paper masking tape, usually used for 3D printing and now widely available in DIY stores. This tape adheres better to Elapor and allows for cleaner edges. I kept the decoration very classic with the usual color stripes—though asymmetrical, just for fun!
Once the paint was fully dry, I moved on to assembly, which was particularly quick.
Wings
The servos—if you choose those sold by Dream-Flight or their original manufacturer equivalent (Emax)—fit directly into the molded recesses after centering the servo and installing the servo arm. You can add a small drop of UHU Por glue if desired, but it is not really necessary. Since the servo leads are not long enough to reach the fuselage, you can use the optional Dream-Flight extensions or extend them yourself with some soldering. A strip of Blenderm tape closes the servo wire channel. Each servo receives a small adhesive square supplied in the kit.
The aileron pushrods are made of piano wire, with a Z-bend on the servo side and a plastic clevis on the control surface side. A small screw locks the wing joiner in place, as on the Alula Trek. That’s it for the wings!
Fuselage
Work on the fuselage is limited to installing the two servos and preparing the extensions for connecting the aileron servos or the battery. I did not install a switch, preferring to plug and unplug the battery each time.
Next come the elevator and rudder linkages. This time, the Z-bend is on the control surface side and the clevis on the servo side. Installing the tailplane is best done by disconnecting the clevis at the servo end. Insert the Z-bend into the control horn, then slide the tailplane into its slot. The fin is installed in the same way.
At this stage, the tailplane and fin fit very loosely in their slots and cannot be flown as-is. It is therefore necessary to apply Blenderm tape along all joint lines. Even then, the parts retain some flexibility but are much better secured.
On the plywood plate, I found a neat trick to keep the cables together: using the small plastic-and-metal ties often used to close freezer bags. Wrapped around the bundled wires, they form a kind of rigid sleeve—simple, quick, and effective.
The battery consists of four 2/3AA NiMH cells. Its position can be adjusted slightly to achieve the correct center of gravity. In my case, even without ballast, the CG was still slightly nose-heavy. One could also imagine using a LiPo or LiFe battery of higher capacity, provided the servos can handle the higher voltage.
The receiver compartment is located behind the servos and has a square cross-section, which is not always convenient depending on the receiver used. My receiver had to squeeze in, with the help of a few careful cuts with a hobby knife.
A quick check on the scale: 374 g. Still firmly in the lightweight category, although closer to the upper end of the range, which starts at 340 g.
Setup
Setup is straightforward. No aileron differential, lots of throw—use all the mechanically available travel—snap-flap enabled, and optionally a lot of exponential on all axes (around 50%) for those who want to tame the beast and avoid surprises. In any case, it clearly sets the tone! Personally, it gave me only one desire… to run straight to the slope and try it out.
Heading to the slope!
In very light wind, below 3 m/s, the Ahi stays airborne and can fly slowly, but will mostly fly flat. Interestingly, it does not like flaps, so it is flown clean. It can turn gently and flat using a bit of rudder alone, or in full three-axis mode by combining aileron and rudder in the direction of the turn. The Ahi shows excellent glide performance, making transitions easier. Its lateral area does not penalize it too much in this respect, even though it was clearly not designed primarily for that.
As soon as the wind picks up slightly, around 4 m/s, the Ahi really comes alive, showing more dynamism and agility, flying faster with a beautiful flight path. Control precision is perfect, and the decoupling between the three axes is total. When you apply a small aileron input—where another glider would immediately start turning—the Ahi banks but holds its original trajectory for a moment. All controls are extremely effective and powerful.
You can then start performing small aerobatic figures, either in a tight space or on a larger scale—the Ahi adapts perfectly. Rolls are perfectly axial and require no correction, provided airspeed is sufficient. The roll rate ranges from huge to downright demonic, with virtually no inertia, stopping instantly on command. The precision is a real joy, and the control response is simply superb considering the glider’s low weight.
When the wind increases beyond 5 m/s, it’s pure nirvana. Still without ballast, the Ahi penetrates the wind effortlessly, flies upwind, covers ground, or strings together violent figures without hesitation. Everything—absolutely everything—works, and more. Inverted flight, knife-edge, inverted spins, positive or negative snaps—there are almost no limits. From precise, large-scale aerobatics to wild, unrestrained acrobatics and reflex flying, improvising in all directions—you can truly let your creativity run free.
Everyone benefits from this: intermediate pilots will have fun performing maneuvers, pushing their limits, even scaring themselves a little while progressing. Expert pilots can refine trajectories, fine-tune figure details, and explore new realms thanks to the precision of the controls.
Durability
I also unintentionally tested durability! The Ahi holds up honorably. However, it is made of an Elapor-like foam, which is less impact-resistant than pure EPP. The plastic insert acting as a skid and extending to the nose does its job well and prevents the fuselage from breaking apart on minor nose impacts. I had two major crashes that eventually damaged the nose, but I was able to repair it with cyano glue and boiling water to straighten it. On the other hand, the small plywood battery-retaining piece breaks fairly easily.
The wings, rear boom, tailplane, fin, and canopy survived without issue. The wingtips are also exposed during tip-first landings—“cartwheeling on a wingtip.” In my case, this resulted in a wingtip crushed like an accordion. I have since reinforced them with two 10 cm carbon strips glued with cyano into shallow cutter grooves.
Conclusion
The Ahi is the glider many have dreamed of for years—certainly for a specific flying discipline, but one that continues to attract more and more pilots, from intermediate to expert. Despite its light weight, the Ahi has a remarkably wide flight envelope. It can fly in very light conditions and almost match the Weasel or Alula Trek, then reveal its true character as soon as the wind picks up slightly.
It then becomes a true aerobatic beast, equally at home in precise, academic aerobatics as in wild acrobatics and the most unimaginable figures you can think of. In short, the Ahi is a major success—a compact glider you can take anywhere. The only regret is that the fin and tailplane are not more easily removable.
A big bravo and another “thank you” to Dream-Flight for consistently delighting us with kits that truly breathe a passion for flying!
What I liked:
- Stunning aerobatic performance
- High level of kit pre-assembly
- Excellent build quality
What I liked less:
- Fin and tailplane must be secured with Blenderm
- Square receiver bay not very practical
- Elapor-like material marks more easily than EPP
Specifications:
- Wingspan: 1200 mm
- Wing area: 20.52 dm²
- Chord: 210 mm / 200 mm / 90 mm
- Airfoil: proprietary
- Weight: 340–425 g (374 g tested) / Ballast: 20 g
- Wing loading: 16.6–20.7 g/dm²
- Controls: 4 servos
Control throws:
- CG: 73 mm
- Elevator: ±30 mm (50% expo)
- Rudder: ±45 mm (40% expo)
- Ailerons: ±40 mm (no expo)
- Snap-flap: ±10 mm (full elevator stick)
Published Mar 14, 2018
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