Usually we stunt flyers don’t worry much about air drag. Many designs with definitely roomy fuselages will confirm this viewpoint. However most of us seem to have a pronounced desire to hide those skinny wheels which - considering their narrow cross section - just cannot have such a detrimental influence on the performance of our airplanes. It is quite apparent: these sleek wheel pants can add a touch of classic elegance and racy style to every design and will even raise the crudest Barnstormer to an elevated class of noblesse. We stunt flyers like this - and RIGHTLY so! What would Aerobatics be without at least a modest touch of beauty!
When living in the Semi Scale or Oldtime or Classic world we have not so much freedom of choice and in some cases are more or less forced to add wheel pants in order to replicate original shapes and images. It’s a lot of work to build these parts precisely and beautifully. But which stunt flyer worth its weight in quarter grain balsa would ever deny to accept this challenge.

  Most of my airplanes have smoothly shaped wheel pants. And while the incredible effort to build them sometimes drives me crazy (you work for hours and hours, time goes by, and construction of the airplane doesn’t move forward ! ), I simply DO NOT renounce on them. I have tried to explain my methods here which doesn’t mean these are the best methods. It’s just what has worked for me.
I’d like to start with the easiest way - the fuselage mounted undercarriage. Pictures were taken during construction of my Don Still “Stuka” which was built for VSC 2009. Because the model had to be sent in a box, it was built the “detachable mode” and so the landing gear had to come off for transportation. The main difference is that the gear is not mounted/ bolted/ glued to the fuselage former. Instead the gear wire slides into the second former which consists of three layers. Otherwise construction is strictly conventional.
Before we start building it’s reasonable to make a very detailed and precise drawing. During the whole bending process it is important to stick exactly to dimensions and angles in order to keep exact control over height (or length of legs) and track (parallelism of axles). (see picture 1)
What is extremely helpful is a suitable wire bender. Pic 2 shows two types. On the bottom there is a commercial tool made by Graupner. I’d like to call it a “baby bender” which is practical for bending soft brass or copper tubes (I actually do this). For bending piano wire we need a more solid tool. This one was made by a friend. Its iron arms are about 60 cm (two feet) long. With this I can bend up to 5 mm wire precisely, and I wished some crazy garage manufacturer could produce and offer this fantastic tool.
  Pic 3 shows the finished wire leg and a red marker which is needed for exactly marking the bend points. You’ll have to learn where to put the marked point on the wire, how to insert it into the bender, and to have the wire bent at exactly the right place and to get optimum results. Pic 4 shows how even sharp bends can be done easily.
In pic 5 the fuselage formers are shown. The fire wall is at left. At right you can see the front and rear layers of the second former. In the middle there is the center layer of the former which has a cutout for the gear wire. A “keeper” part is slid in after the wire is in place. Wire and keeper are held in place when the wing (incuding fuselage bottom part) are mounted to the fuselage. Pics 6 and 7 show the separate parts and the combined unit.
In pic 8 the “pant bearers” are soldered to the wire legs. I use little brass plates in order to get some gluing surface and to be able to align the wheel pants carefully. A real good solder joint is necessary here.    
Wheel pants are built in halves, with the inner halves attached first. As can be seen in pic 9 I use some kind of “jig”. I have two ply plates with a third one glued to the second plate; that way this jig stands really vertical. The readily bent gear wire is held between the two ply plates. This whole unit is placed on a precise top view drawing. Two small balsa blocks are placed UNDER the axles - because the bottom of the pants is lower than the axles. Now the whole unit is aligned carefully over the drawing and the wire solidly clamped in the jig.
After cutting small slots into the inner pant halves, we can glue these to the brass keepers with 5 minute epoxy; see pic9. This allows us to align these halves very carefully in horizontal and vertical position. The underlying drawing is very helpful here. A few small pieces of glass cloth glued over the keepers help to strengthen this joint. Before I add the outer halves I paint all insides with fuel proof laquer (pic 10).
Now the gear legs have to be covered (pic 11). There’s not much that can be designed in advance - it’s mostly cut, fit, and sand. A microballoon /epoxy mix to smooth out gaps and dents will save your nerves. After many cracked experiments I finally found the solution: these balsa legs are covered with fibre glass ! Pic 12 shows the final installation. Be sure to sand some definite clearance between the gear fairing and the fuselage to allow for some slight forward or backward bending when landing on uneven surface - or the fuselage bottom will be hurt seriously. Pic 13 is a fuselage bottom view with the gear pushed into the former.
Pic 14 shows all the airplane parts arranged together. It can be seen that a detachable airplane can be easily transported in a box of rather small dimensions. And it’s quite obvious that a removable landing gear helps to reduce these dimensions quite drastically. This aspect doesn’t quite fit within the scope of our topic. But it deserves mentioning - and I just had the pictures !
      Oh - since we are at it - there are other ways to shape beautiful wheel pants, too. For lack of a better word let me call it “open wheel cutout”. Similar solutions have been used in the past for full size airplanes. Since they are no longer used today they bear an aura of nostalgia, simplicity, and solidity. They are much easier to construct, give access to wheels, and allow change or replacement of wheels. For small models they can even be kept solid (with light balsa it doesn’t pay to hollow them; or would you try to save 4 gramm ? I did - and I won’t do it any more) . For larger shapes two layers of thick balsa - partly hollowed - will do. The wheel may well protrude out of the pant outline; this will even improve the nostalgic looks. Imagine: more impression with less work !! Where else can we get this.
  So far I have explained my method of building a fuselage mounted landing gear. Except for the “detachable aspect” this is a basic solution for this construction detail. But we don’t have fuselage mounted landing gears only. Many control line aerobatic airplanes have wing mounted gears - and these are some of the most beautiful model airplanes in the world. I’ll try to offer a building sequence in pictures which show how I approached this task. Click on the pants button and see.