Stevens Aeromodel Helium MG

TIPS FOR SUCCESS – ASSEMBLY

Ive got several more tips building this kit than with a typical ARF. Youll do well to treat the Heliums assembly like a 3D jigsaw puzzle where the manual guides you to the solution. Each piece is cut to within five thousandths of an inch (.005) accuracy, so the parts fit is generally incredibly precise. If a part doesnt fit, it is either the wrong part or youve got it backwards. Youll want a perfectly flat and smooth building board to work from, and Ive found that composite ceiling tiles work great. They readily accept pins and stay flat throughout most temperature and humidity conditions.

Youll also need both thick and thin CA, although thin CA will be used for most of the construction. Thin CA applicator tips are a must to keep your gluing controlled and tidy. Each of the joints is tight enough that thin CA wicks nicely into them for a great bond

with minimal residue. In addition to following the instructions precisely, I tend to work a couple of steps between final gluing. This allows the jigging feature of the laser cut structure to better align itself as the assemblies come together.

The only area of the build where I see potential to make an unrecoverable mistake is with the joiner blades and their associated slots that join the outer panels with the inner wing section. Each Delrin joiner slots into the individual panels and requires a tight yet still removable fit. If excess CA were to be applied or inadvertently enter the slots, it would prevent the joiners from fitting correctly. Be very careful to apply only enough adhesive to get the job done in this critical step.

For me, basic assembly is the most enjoyable part of any kit build. Each part coming together is very fulfilling and stokes the instant gratification fire that seems to burn in me. That said, take your time and ensure each assembly is square and plumb before final gluing. Using that technique, youll be rewarded with a great flying model surprisingly quickly.

COVERING TIPS

Although youre probably itching to heat up that covering iron, the first step to a great covering job is a great sanding job. I start with 150 grit and work down to 400 grit. Stevens Aero included a really nice foam sanding block that does a great job. I supplement that with a traditional 12-inch aluminum sanding T. An easy way to check your sanding work for imperfections is by lightly brushing your fingertips over the surfaces to feel for imperfections. All but the smallest imperfections will show through the covering, so your time is well spent here. Finally, I use a painting tack cloth to remove as much sanding dust as possible.

Covering is my least favorite part of the kit building process and I this attribute my lack of covering creativity. For me, covering is functional. For the artistic in our group, it should look like a blank canvas awaiting your masterpiece. SA Aerofilm Lite is a great choice for the Helium. It is a very lightweight covering, and takes very little heat to shrink. Be sure to test your iron with the covering on a low setting and slowly work the heat higher as necessary. I prefer to tack the entire outside of each structure, including trimming and sealing the edges before shrinking. With some care, a heat gun can be used to shrink the open covering areas tight. Finally, youll want several sharp No. 11 hobby blades on hand. Aerofilm Lite tears very easily when snagged, and quickly dulls blades.

ELECTRONICS AND FINAL ASSEMBLY TIPS

The rudder and elevator servos mount upside down in the fuselage and attach to the flight controls with genuine Dubro pushrods and control horns that are included in the kit. I chose the recommended Hitec HS-65HB servos, and have been quite pleased with their centering and speed. The receiver mounts on the top of the battery tray and can be accessed with the wing removed.

Assembling the Helium takes no more than five minutes at the field due to its unique magnetic outer wing panel retention system. Several rare earth magnets snap the panels in place, while either rubber bands or small Nylon wing bolts secure the main wing panel to the fuse. Swinging an 11-inch folding prop, the Helium has plenty of rudder authority for taxiing. Crosswinds can be a problem for traditional takeoffs with only rudder/ elevator controls, in which case a hand launch makes more sense. Simply power up and give a slight toss into the wind.

With such a high power to weight ratio, the Helium can climb virtually straight up to altitude if wanted although I prefer a more sedate partial power climb. Roll performance is very responsive with the sharp outer panel dihedral angle. Overall, the Helium feels quite responsive and nimble for a sailplane of its size. With the power off and the prop folded, the Helium has a reasonable glide angle and shows lift well. For pure soaring, I prefer to lower drag by removing the landing gear and hand launch the model with either belly landings in the grass or hand catches at the end of the flight.

I was a little bit concerned about the strength of the outer panel Delrin wing joiner, but it has proven to be plenty strong for traditional sailplane aerobatics. The addition of the spoiler panel adds another fun aspect to flying the Helium. The first time I deployed the spoiler I was shocked by the amount of nose down pitching moment. The manual comments on that, but it was more than expected. Ive since programmed in a 20-percent pitch bias with the spoiler extended to fully compensate for this tendency. The descent angle is extremely steep with full spoiler extension and the Helium retains full controllability. I programmed the spoiler control to a side slider on my Aurora 9 transmitter which makes it easy to reach. I prefer to approach with partial spoiler, reducing it to zero by touchdown to minimize the rate of descent for the flare. The landing gear is somewhat springy, so it rewards smooth touchdowns but will protect the model from damage if you plop it down from time to time.

CONCLUSION

The Helium has been a really fun project for me for a number of reasons previously mentioned. Although I have gotten out of the kit building habit, that aspect of the process has reignited my interest in building for which I have to thank Bill Stevens. As much as I enjoy flying the models, I really do enjoy assembling them as well. I even enjoyed my simple covering scheme. Best of all, of course, are the hours I get to spend evaluating this new design at the local schoolyard where the thermals boom.