For the last five years or so, there has been a lot of fuss in the aeromodeling world about all those flat foam airplanes. Just what is all the ruckus about anyway?

In a word FUN, that’s what. They seem to fly great, they are cheap, easy to build and you can fly them anywhere from a gym to a baseball infield or at your regular model flying field. You will find yourself laughing at the antics of your airplane. After all, how many of your models will knife edge loop in 2 to 3 feet! (Ed. Note: I call these aircraft “packing material” since they are made from thin foam sheets usually used to protect package contents during shipment. But they are a lot of fun to fly.)

Let’s build us a ‘Flatana’

During the assembly of this ARF aircraft, I made a lot of notes of the things I thought the builder should be aware of and some things I thought the builder should do differently. Every experienced modeler will have his or her own way of doing something. If it is based on experience (and that experience has worked well in the past) then go for it. Please be aware that the instructions ARE well thought out and have been worked on until they do work well. Follow the directions—where Great Planes and I differ, read both versions and figure out what will work best for you.

One of the first things Great Planes tells you to do is make some decisions. You cannot use conventional equipment on this model. Conventional servos weigh about 1.5 ounces. The correct servos for this aircraft are weighed in grams. The total aircraft weight, ready to fly, of this airplane is just 10 ½ ounces! Read the “decisions you must make” section.

Photo 1          Photo 1A

As shown in photo 1, I used three Hitec HS-55 servos, each weighing just 0.28 ounces (9 grams!), the Berg 4L receiver which weighed only 0.28 ounces (4 Grams) and the 7-amp ElectriFly speed control model C-12, which also weighed 0.28 ounces. I used a larger battery than recommended for this project, the Cermark 900mAh, 11.1-volt Lithium Polymer (Li-Po) battery weighing 2.16 ounces, in order to get some extra air time per flight. Great Planes recommends using the Electrifly 3-cell, 640 mAh battery pack which weighs 2.1 ounces. Regardless of the battery selected, it can't weigh more than 2.3 ounces according to the directions.

Foam safe CAA was the only glue used except for some thin CAA on the control rods. It is quick and easy, just be sure to not let the glue string out and get all over the artwork. The medium, foam-safe, stuff tends to produce ‘strings’ as you take the glue bottle away from the joint; annoying, but harmless. I like to use cotton swabs to absorb any excess glue. The only glue that provides strength to the joint is the stuff inside the joint, all the excess adhesive dumped onto the joint adds only weight.

Photo 2

All the carbon rods and tubes are pre-cut to the exact length needed. When Great Planes tells you to use the 1/8 in. by 8 7/32 in. tube, be sure to measure it and use the correct one. On an earlier Foamie, I didn’t pay attention and ended up having to improvise a connector from some scrap rod I had. Not a lot of fun (and it was heavier).

Photo 3

Assembling the Flatana is rather straight forward but there may be a few items to make sure are properly done. First, pay particular attention to the part number on the two plastic parts trees. Make sure you use the correct part number during assembly.

The photo instruction manual contains many “Expert Tips” designed to help the first time “Foamie” airplane builder. These tips proved very helpful. But, if you have the right tools like a drill bit set, there might be an even better way to accomplish a few of these tasks.

As a general building tip, I find it easier, when assembling the hinges, to put all the C-2 clip hinges on the carbon fiber hinge tube first, then glue the two end hinges in place before gluing the rest of the hinges.

Photo 4           Photo 5

Before removing the C-3 ring from the parts tree, drill it out with a #32 drill bit. You don’t need a power drill, just twirl the drill bit in your fingers to relieve the hole. It is easier and more accurate than using the ‘Expert Tip’ on page 8. I am specifying a number drill bit here, and in other places. Most of the time, a fractional size is too large or too small.

Use a weight, as in photo 5, to hold the part sheet in place while cutting out the foam parts that make up the Flatana. Use a very sharp hobby razor knife to cut through the score marks. Take your time as these parts are already “finished” and will not be covered. Any mistake here will translate directly to the completed airplane.

Photo 6

I urge you to go out and buy one of those cheap, imported drill bit sets. The ones that have 116 bits in them: number bits from 1 to 60 and fractional sizes from 1/16 in. to ½ in. (in 64ths) and ‘A’ to ‘Z’. They’re cheap! I paid $39.95 and I have seen them for even less. They are not the best bits in the world but, we’re only using them on balsa, ply and plastic. There is a nice chart of actual drill bit sizes at:

http://bobmay.astronomy.net/misc/drillchart.htm

(Ed Note: The Black and White photos that follow are from the Flatana Construction Manual. These detailed photos are extremely helpful. I think they serve Sport Aviator readers better because of the extra details they contain. They also serve as great examples of the kind of construction detail contained in the manual. Because building a “Foamie” is so different from building a conventional model aircraft, this article goes into far more construction detail than normal.)

Photo 8

Don’t mix up the A-1 clevis with A-2. They look alike so go by part numbers. Drill out each clevis hole with a #38 drill (by hand). If you don’t have, and are not going to get, the drill bit set, the “expert tip” using the #11 hobby blade does work. Just be very careful to not over enlarge the hole. This is a highly responsive aircraft and excess control slop is not going to be appreciated. Try to use the #38 drill bit if you can.

Photo 7

All the Flatana control surfaces use the hinging method shown in photo 7. Carbon fiber rods hold strong plastic hinges in place. The carbon rods also act as stiffeners to reinforce the airframe. Make sure that no CAA gets into the bearings of the hinge. CAA bonds few things more strongly, except maybe skin, than it does carbon fiber.

Photo 9