Quorneng's build blog

Maybe it's just not flying fast enough.

Back to the Libelle
The 'solid' canopy was made the same way as the fuselage - Depron planks.

Being just a 3mm skin overall it is very light and stiff and finished in a delicate shade of blue!

It is clipped under the cockpit coaming at the front and held down with magnets at the rear.

After filling and sanding the whole airframe is painted in matt white emulsion and then sprayed with extra firm hold hair spray to give a 'silk' finish.
Attempting a true gloss on Depron would be too heavy.

As the Libelle is so light it only need a modest 9A motor with a white 7x5 folder but will nevertheless have 150w/lb available.

The 2.4Ghz radio is installed above and behind the wing.

The 1500mAh 3s is mounted on the cockpit floor.

This is actually a pretty big battery for the maximum motor current (just 6C) so it also has a significant 10 minute full power duration.
The wing is secured by 2 nylon bolts.
The Libelle Completed.

It weighs 13.5oz ready to fly - not bad for a 2.1m span motor glider.

The interesting bit will be to see just how badly it glides as the very narrow wing chord gives even lower Reynolds numbers and means a poorer lift to drag then might be expected from the wing section.

The maiden was always going to be a "this could all end badly" sort of thing as I had no idea if it would be controllable or even if the CofG was in the right place!
The only thing I did know was it pretty delicate with little crash resistance.
Well it does fly. The CofG was indeed too far back so the maiden was a series of stalls and wing drops as I struggled with holding the stick forward in conjunction with full elevator to manage the wing drop.
This was the first part of the actual maiden.

I did just manage to get it down in one piece
With the battery moved forward it was much better so I got a bit higher and started to throw it around a bit - and promptly lost the canopy - but just to convince myself the wing was actually strong enough I did a loop.

So far so good but these were only short 'proving' flights.
Full testing will have to wait for better and warmer weather.

nicely done sir.

She looks so graceful in the air, beautiful- well done Simon!!

For a minute on the vids thought you were going to try for between those rugby posts again

Back to the recalcitrant Frog Wren!
Rather too much wind this morning for such a slow flyer but I needed to test it so here is the video

The over size fin & rudder coupled with the wind made it a bit of a handful.
Much of the flight has had to be edited out as the tiny Wren was just to small for the camera.
Full power only used once and achieved a 45 degree climb.
I did manage a couple of loops and a completely unintentional 'flick' roll (0:54).

As it came back completely undamaged it goes down as a success.

Now to cut back the fin and rudder.

keep going sir.

she looks good.

That "untentional flick roll " would have had me throwing the Tx back at ya in a panic lol!!

Looks brill Simon..and back in one piece, bet you are chuffed

When the weather gets better I would like to find out how to do it on purpose!

It is supposed to be possible to roll a plane with only the rudder and elevator - although it is much easier if you have ailerons.

Now I know it flies my intention is eventually to get it back to the original twin fin configuration but the weather forecast in horrible - again!

Eric
I assume the flick (snap?) roll I achieved was caused by a pronounced one wing stall as a result of excessive AofA (too much up elevator) as I pulled out with some bank on (corrected with rudder) following an 'untidy' loop.

So I guess fairly slow, stick sharply back and a boot full of rudder as the nose begins to rise.

Quorneng wrote: Back to the recalcitrant Frog Wren!
Rather too much wind this morning for such a slow flyer but I needed to test it so here is the video

The over size fin & rudder coupled with the wind made it a bit of a handful.
Much of the flight has had to be edited out as the tiny Wren was just to small for the camera.
Full power only used once and achieved a 45 degree climb.
I did manage a couple of loops and a completely unintentional 'flick' roll (0:54).

As it came back completely undamaged it goes down as a success.

Now to cut back the fin and rudder.

Let's look back at that video, it's hard to make out anything except the landing & that was a nose dive into the deck.
I'm sorry if I sound condescending but that model should have come in on a glide path .... it damn near tent pegged.
I'm not going to pull punches here, this forum is not about that.... I'll probably get all the stick when I maiden this Nemesis, so I'm getting my punches in first..... you can beat me up later.

Pol

Thankyou Simon for a very interesting and informative double build thread.I enjoy the challenges you give yourself.