How to make an ultralight look like a Piper Cub

How to make an ultralight look like a Piper Cub!

Well, the answer to that question is to start with a Belite and put an UltraCub Turtledeck on it.  The kit costs $500.  It includes all of the precut formers, along longerons and lightweight dacron fabric.  All the formers are CNC cut Baltic Birch plywood or aircraft quality Douglas Fir (in either 1/4″ x 3/4″ size or 1/4″ x 1/2″).  All you have to do is cut the wood strips to the right length and use good glue and lots of clamps.

The building surface is the back of your Belite.  This guarantees that whatever slight warps you built into your fuselage will be reflected in the turtledeck, guaranteeing a good fit and a good look.

In the following photos, we’re using our super secret upcoming four stroke demonstrator airplane as the basis  of this particular turtledeck and resultant ultracub.

The photos are very self explanatory, so I’ll keep comments to a minimum between the photos.  We’ll start with a photo of the completed turtledeck, so you can see what you are trying to make:

Completed Turtledeck for a Belite Ultralight airplane — UltraCub

From left to right, there are six formers: A through F.  There are two window formers, and two window eave formers, four angle gussets, and four square gussets.

Start by fitting the “A” former, the window formers, and the “B” former together.  You’ll need to cut off the bottom of the “A” former, unless you want to leave the turtledeck permanently attached to your plane.  Cutting it off allows the former to be placed over the flaperon cables.  Also check the fit of the tabs.  They are a very tight fit and will need some help with your file or X-Acto razor saw to achieve a perfect fit.

Bottom of A former is cut off as shown

Gluing the A and B formers along with the window former
Gluing the window eaves former
Window eaves after clamps removed; bottom longerons (1/4″ x 3/4″) placed and glued
Gluing C, D, E formers to bottom longerons
Gluing F former in place to bottom longerons
Gluing top longerons in place — two 1/4″ x 1/2″ and one 1/4″ x 3/4″

In the above photo, the longerons are glued using lots of clamps.  As they are bent, this will require making sure that the overall turtledeck structure stays flush to the fuselage.  You can see some big clamps along the side of the fuselage which help keep it all clamped down and square.

Use lots of clamps.
Side longerons (1/4″ x 3/4″) and front angle gussett glued in place.
Top corner longerons (1/4″ x 3/4″) glued in place.  Longeron is fitted first to butt into corner.
Top corner longerons and lots of clamps — a recurring theme.
1/4″ x 3/4″ stiffener glued to back of B former.
Angle gussett glued to top longerons on each side
Square gussett glued in place on C former.
Additional (sideways) top corner longerons glued in place, forming 90 degree angle longerons
Between Former stiffeners cut, fitted and glued in place.

The purpose of the stiffeners in the above photo is to prevent the bottom longerons from bending when the structure is covered with lightweight dacron fabric.  Of course, to work well, we need to add a second level of stiffeners:

more stiffeners on the higher level.
short longerons cut, fitted, glued and clamped in place.
90 degree square gussett on E former
All longerons trimmed off, view from front.
quartering view of turtledeck for Belite ultralight aircraft — UltraCub.
view of rear of turtledeck.
Your turtledeck is now ready to cover with Dacron fabric.

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