What to expect:

AS YOU GO BIG

by Len Buffinton

Let’s face it, bigger flies better. If you want to start an argument, there’s a good way to begin. But the facts are the facts. With model airplanes, there are aerodynamic advantages to having a larger plane. As you increase the size of the model, its going to get heavier, but you now have the wingspan and lift to support the increase in weight. Although I’m not qualified to talk aerodynamics, I certainly can talk about bigger planes and heavier weights.

When you’re are ready to step up from your current sailplane, whether it’s a 2 meter Easy Glider Pro, or a 4 meter glass slipper, here are some tips to help the transition go smooth.

1. Transportability:
   

   10.6m Nimbus 4, the wing break down into 6 pieces

   The first thing you need to decide when shopping for your next dream machine is how it breaks down. As sailplanes get bigger, the wings will start to get too big to handle. The manufacturers address this by offering multiple piece wings. It seems pretty standard that once you pass through 4 meters, all sailplanes will have multiple piece wings. Just to be clear, when we say a plane has a two piece wing, we mean it has a left and a right but then those wing panels come apart again, its a 4 piece wing. A 5 meter sailplanes wings will usually separate a little ways in from the tip. Making it about the same as transporting a 4 meter wing. Moving onto 6,7,8,9,10 meter wingspans, the sailplanes will have multiple piece wings. There are exceptions though. I was able to order a LET 6 meter ASH26 without breaking each wing. That meant instead of a 4 piece wing, (2 pieces each side) I ordered the 2 piece wing and just have a left and right wing to assemble. Each panel measures just over 9 ft and since I have a trailer, this was not an issues. The fuselage is also going to get big, so be ready for that too. Not only in length, but also in the fin height. The fin height of an 8 meter sailplane can easily approach 24″ tall. Most manufactures will list the actual length of the fuselage and how the wing panels breakdown, but if they don’t, be sure to ask.

2. Weight:There is a big difference in the weight of a 4 meter glass sailplane to a 6 meter glass slipper. More than you would think. When the wings get bigger, they get heavier. More structure is needed to handle the loads, so they are build stronger, this means weight. The fuselage gets longer, the tail gets bigger and because of all that, you end up with more lead in the nose to compensate for the longer tail moment. Also, with bigger sailplanes, the servos for the elevator and rudder are often mounted in the tail. This adds to the balance weight needed, but that’s OK, you need the weight. Believe it or not, as the planes get larger, you NEED weight to make them fly properly. Many times, especially with balsa built models, the builder will keep it as light as possible during construction, only to find that it does not fly well. The plane has so much wing now it will not penetrate. If there is no mass to keep the ship moving, it just flounder around the sky. It’s odd, but there are sailplanes flying around with 3lb bricks glued inside the fuselage just to make it fly better.
   

   LET Reiher being hauled back to the flightline

3. Equipment:Here is the one that always gets overlooked, the equipment. You will need a few more servos to run a 6 meter plane than you will to run a 4 meter plane.
   

   Nimbus Cockpit, Plenty of wire and even dual receivers

On a typical 6 meter sailplane, you will have at least:

• 1 or 2 elevator servos
• 2 spoiler servos
• 4 aileron servos
• 2 or 4 flap servos
• 1 retract servo
• 1 tow release servo
• 1 rudder servo
• 1 brake servo (optional)

In the worst case scenario you will need 16 servos and in the best case you’ll need 12. These servos need to be of good quality. You are trusting a big, expensive sailplane to these little devices, so make them good ones.

You will also want to run two battery packs for the receiver. Plus, if the plane has a retractable gear, you’ll want to power that with a separate battery pack too. Which brings us to the most common question, WHY? Why do you need a separate battery for the retract? If you have a retract on the sailplane that uses power from your normal flight pack, and the wheel picks up a stone or a stick when it is taking off, jamming the unit when you try to retract it, the battery back will drain in very short order and you wont even know it. By separating the retract form the receiver packs will certainly save your plane someday. Each battery should have its own switch too. There is no sense in putting in redundant batteries and having only one switch, what happens if the switch goes bad?

Moving up to a larger sailplane is a natural progression. Some move up quickly, others will move up very slowly, but the same results happen in the end, they’re all glad they did.