Thermy 4: Planning the Fuselage

Preliminary Frames for the second nose draft, complete with motor and mounting.
Preliminary Frames for the second nose draft, complete with motor and mounting.

After drafting a first version of the nose, there’s work to do on the fuselage. So this week, it’s going to be a lot of frames to draw.

I start with adding some random sketches that give me an idea of the dimensions and shapes involved. I also try to add a platform to the fuselage’s top where the wing can be mounted.

First nose draft finished, moving on to the fuselage.
First nose draft finished, moving on to the fuselage.

However, it’s only now that I realize almost all modern soaring planes feature mid wings, while the Thermy 4 is designed as a shoulder wing. At this point I give up on the idea of simply adapting the nose and fuselage to a rounder shape, but start again from scratch.

This time, I want to give priority to the needed dimensions, so I start by researching a suitable brushless outrunner and model it so I can fit it into the nose.

Preliminary Frames for the second nose draft, complete with motor and mounting.
Preliminary Frames for the second nose draft, complete with motor and mounting.

The measurements are taken from the three-sided drawing of an actual ASW-28. Since I haven’t deleted the first draft, I can get a comparison between the first and second draft. The difference is noticable, to say the least.

Comparing the new nose version to the old one.
Comparing the new nose version to the old one.

However, I’m commited and I want to give the fuselage at least one go before I start to consider the feasibility of this new approach. Since I’m breaking fresh ground, I need some sort of general idea what the fuselage’s shape is going to be. So a gauge is drawn which will help me to find the right place and dimensions for the following frames.

A gauge for the fuselage's shape is in the making.
A gauge for the fuselage’s shape is in the making.

With two of these finished, the fuselage is starting to take shape and I start to feel a bit more comfortable about the whole endeavour.

Preliminary fuselage based on the gauges.
Preliminary fuselage based on the gauges.

And this is the current state of affairs. Stay tuned for further developments next time.

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