Cheetah

Thanks for the kind words.

I did wonder if the 'fixed' rudder was actually flexing a bit when presented with a side force. It is thin Depron just glued to the trailing edge of the fin.
As a possible solution the rudder currently overhangs the 'cut off' rear fuselage. By adding a Depron cone to bring the rear fuselage to a point apart from very marginally improving the aerodynamics it would also support the rudder.

I do agree with the following,, very nice work.

paul d wrote: I disagree Simon, I thought it looked perfectly powered considering it's weight and the fact it's a glider.
Bloody well done!!

As I reported in "Been Flying" I did some significant damage to RC converted Cheetah chuck glider.
It piled in nose first snapping both sides of the built up Depron wing from the fuselage and crushing the nose and motor, although none of the original 'rubbery' foam was damaged.
So pissed off I did not take a "damage" picture.
Rather than rebuild the centre section I decided to simply cut back the damaged ednds and re join the wing at the centre. This reduced the span from 1370 mm to 1240 mm.

Apart from the small span reduction the change is invisible.
The nose required a new bulkhead/motor mount.

A 'printed' item so not too much of a problem. I did take the opportunity to improve it a bit while I was at it.
The Depron 2mm skin around the motor will be rebuilt.
The folding prop was un damaged although its printed 'push on' spinner was destroyed so simply replaced.

Rain, thunder and lightening today so no flying anyway.

It took most of the day but it is now all back together.

The final mod that I was not expecting was to move the elevator servo.
It was originally on the right hand side but after I had placed it there I noticed that the fuselage was a touch 'bent' and sods law the tension of the pull/pull wires made it worse. I thought I had straightened it sufficiently with a bit of heat but after 2 years it was really noticeable and probably was effecting it handling.
The solution was simple in theory put the pull/pull on the other side but extracting the fully embedded servo was definitely not!

But got there in the end.

Having decided to completely remove the Depron built up centre section and use just the original foam wings I have been spending a ridiculous amount of time expanding my FreeCad knowledge a bit to get the hang of 'lofting'. In this case from the shape of the cut off fuselage to the circle of the spinner including a small nose intake for motor cooling air.

Like mast printing there are some limitations particularly in small single wall items but fortunately the cowling only weighs 0.7g so despite many attempts to get what I wanted it does not use much filament
The object was this cowling would exactly fit over and be positioned by the motor mount.

The whole nose has less width than the previous installation so the prop folds better.

It won't make the slightest difference to the Cheetah but I do now know a little bit about 'lofting'.

The original foam wings restored.

The wing is in one piece so I had to remove the aileron with its horn so I could slide the wing in place.
With the built up centre section it had a wing area of 167,920 sq mm. The original foam wing is 111,600 sq mm. A reduction of 34%!
There is also a slight weight reduction of 9% but it still results in the wing loading rising by a whopping 30%.
Although it will only have to 5% faster the problem is it was not exactly over powered to start with.
We shall see.

It appeared to be reasonably calm ay tea time so I decided to test the now complete 'Original Wing' Cheetah.

I reasoned as it will fly quite a bit faster it should handle any wind better.
I was wrong! It just gets thrown about that much faster!
I did manage to prove it had sufficient power climb quite nicely but stopped before it got damaged.
Just needs a calmer day to get it properly sorted.
With the narrower motor cowl and smaller spinner the prop now folds quite nicely.

There is still a small nose inlet and a pair of side vents for motor cooling air.
As all the weight is now carried just by the original foam wings I have added some surface mounted printed "spar flanges" at points of maximum deflection.

Each is 0.35 mm thick (2 layers) with the filament bead direction of both layers running along the strip.

The total weight of all four strips is just over 1g. It certainly reduces the otherwise rather alarming flex when it is lifted by its wing tips.

Lofting is FreeCAD is as much an art as a science. Endless tweaks available... and then that final tweak where it collapses into a tangled virual mess. Nicely done. Can't wait to see where else you take this. -Jon