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chiloschista

Trisel - tailles, heavy, heavier, eco, volcanic ...

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chiloschista

Probably a sensible idea. But that means you will have to build it strong with strong spars and such. :)

Nothing wrong with old school really. :D

 

I'm just following the state of the art: top and bottom pinewood spars, joined by a single vertical grain 3mm balsa sheet.

Because of the high sweep and elliptical geometry I had to build it around three spars (watch the drawing).

Right now with only top balsa sheet, the wing is really stiff already. A little less on torsion side, but that will come with full sheeting.

 

No need to overdo; if I only think at combat planes: the have a hard life and a glow engine on board. They last so long ...

On a bigger glider things changes obviously, e.g. the 3.88m Habicht laying around.

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Graham_C

I would choose basalt over carbon for most purposes. Except perhaps if weight is the absolute primary aspect.

Light weaves of basalt are still hard to find and they are not quite as strong as carbon so you need to lay them on a bit heavier.

 

Weight shouldn't be a problem - everyone fills them with ballast ayway :lol:

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chiloschista

Hello,

 

top covering is done and servos mount also glued.

 

P1030753.JPG

 

P1030756.JPG

 

P1030759.JPG

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chiloschista

Just for fun here are few pictures from aerodynamics study.

Results are well confusing me :huh: but I guess software wind tunnels really reaches their limits here.

Maybe I will try to simulate it with other softwares.

 

The first one is the planform I'm building, the second one is a swept forward simulation of the same surface and third one is Trisel #4.

I know for sure that the squared planform creates a lot of drag, especially on Trisel #3: it does not pick up the speed it should.

From this study it seems they are almost the same with the #4 winning and that could not be true, even with its smaller surface.

 

Not to mention coefficient moment, which should end with an unstable plane, when Trisel #4 flies like on rails...

 

XFLR5%2B05.01.2015%2B012212.jpg

 

XFLR5%2B05.01.2015%2B012345.jpg

 

XFLR5%2B05.01.2015%2B012438.jpg

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chiloschista

Hello,

I was starting to think that the Trisel #3, with 1kg weight and a 7.5% airfoil, could not work well...

... well, I doscovered that it's just a matter of right conditions B) (should really relocate near Rhossili).

Ric

 

 

Just a bit difficult to land, with that weight and without any help to slow it down.
Ric

Edited by chiloschista

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chiloschista

Well, it's time to resurrect this thread, just to say that the Trisel #5, aka volcanic, now renamed "The sole", went finally in flight: ouff!

 

Improvements over the previous versions are elliptical planform, which decrease a lot drag, especially at wing tips, better joints wing - fuselage, weight as it's the lightest.

It was meant for light to very light conditions and I guess I reached the goal. It let fly slowly, but it get speed very well. No bad behaviours, no tip stalls. Maybe a little responsive on pitch despite a computed static margin of 5%.

Anyway PredimRC did very well the job of CG computation. It was not as well for the Trisel #3 and that is strange because the planform of the #3 is simpler. I got 112mm from leading edge, with a static margin of 6%, and the test flight was a nightmare. It is flying well now at 93mm. The #5 was computed at 92, I set it at 90 and it went out of hands just straight.

Best regards,

Ric

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oipigface
9 minutes ago, chiloschista said:

Well, it's time to resurrect this thread, just to say that the Trisel #5, aka volcanic, now renamed "The sole", went finally in flight: ouff!

 

Flies like a flounder?

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chiloschista
1 minute ago, oipigface said:

Flies like a flounder?

Ouff, John! Please stop to force me all the time to use translators ...

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oipigface
3 minutes ago, chiloschista said:

Ouff, John! Please stop to force me all the time to use translators ...

Sorry, Ric! Couldn't resist that one.

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chiloschista
1 minute ago, oipigface said:

Sorry, Ric! Couldn't resist that one.

You are always so funny = : D

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martynk

Could be a Plaice..

 

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oipigface

Looks as if it could do with a Dab of paint, though.

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martynk

You have no sole...

 

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oipigface

...but at least I know my Plaice.

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evad
4 hours ago, martynk said:

You have no sole...

 

lemon receiver ........ 

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Jef Ott

It's not a scale model though

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oipigface
7 hours ago, Jef said:

It's not a scale model though

Neverltheless, the design is Brill.

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mikef

Oh my cod!  I can't believe what I'm herring here.

I'd like to sea this model skating about in wave lift under a mackerel sky - you could have a whale of a time.

(Can't kelp feeling all this fishy stuff and is a bit unfair when Ric's first language isn't English.)

In the CFD pictures above  (Jan 5th) I noticed how the swept back planform gave a greater effective span (between the tip vortices) compared to the same shape reversed to swept forward.  Is the line on the wing upper surface a turbotlator?

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Jef Ott

I'm sick to the gills with all this pollocks. 

 

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oipigface
8 hours ago, Jef said:

I'm sick to the gills with all this pollocks. 

 

Me grim too.

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