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AUDAX

Publié : 12 nov. 2013, 13:13
par claudecuinet
Bonjour

Le dernier d'Alexandre Voicu

https://www.facebook.com/alexandru.voicu.754?fref=ts

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Re: AUDAX

Publié : 12 nov. 2013, 13:49
par Voldos
on voit peu d'articles sur les systèmes contra-rotatifs
Mis à part en F3P, est-ce que des compétiteurs français l'utilisent en F3A ?

Re: AUDAX

Publié : 12 nov. 2013, 14:09
par claudecuinet
Bonjour Christian

En France, il y en a au moins un. Il a fait un championnat de France avec.
Aux US, comme le système est conçu et vendu par Brenner qui est américain; il y en beaucoup qui l'utilisent malgré le poids supplémentaire et le coût.

http://www.rcuniverse.com/forum/electri ... es-42.html

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Re: AUDAX

Publié : 13 nov. 2013, 20:37
par Cedric Carayon
Voldos a écrit :on voit peu d'articles sur les systèmes contra-rotatifs
Mis à part en F3P, est-ce que des compétiteurs français l'utilisent en F3A ?
Je connais un pilote inter qui vient de recevoir ce système là, et si les essais sont concluant on le verra tout au long de la saison prochaine

Re: AUDAX

Publié : 13 nov. 2013, 22:23
par nonoleptitrobot
Cedric Carayon a écrit :
Voldos a écrit :on voit peu d'articles sur les systèmes contra-rotatifs
Mis à part en F3P, est-ce que des compétiteurs français l'utilisent en F3A ?
Je connais un pilote inter qui vient de recevoir ce système là, et si les essais sont concluant on le verra tout au long de la saison prochaine

Peux -t-on avoir ses initiales ?!

Re: AUDAX

Publié : 14 nov. 2013, 09:01
par Roland
JCLH

Re: AUDAX

Publié : 31 juil. 2014, 16:36
par Bloodhound
Thank you Claude for starting the Audax thread. It's been a while, but we made some progress on the model so i will post some updates here.

The model will be full composite, so this means we had to manufacture molds for fuselage,canopy,wings, stabs and rudder. All the mold plugs were machined on a CNC router, here are a few pictures of the stab mold plugs during machining process:

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Re: AUDAX

Publié : 31 juil. 2014, 16:38
par Bloodhound
Pictures of the finished stab molds:

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Re: AUDAX

Publié : 31 juil. 2014, 16:55
par Bloodhound
The stab layup consists of a sheet of 1.2mm Airex as core material, sandwiched between 2 layers of 25g/m2 fiberglass. The internal structure looks like this:

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It's maybe a little stronger than needed, so it will be simplified in the future to make it lighter.

Re: AUDAX

Publié : 04 août 2014, 19:14
par Bloodhound
CNC machining the wing mold plugs:

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Re: AUDAX

Publié : 11 août 2014, 20:34
par Bloodhound
Finished wing mold:

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Re: AUDAX

Publié : 18 août 2014, 08:38
par Bloodhound
We built a few composite fuselages in the past but composite wings are a new experience for us. We only found very limited online material about this subject, so the only way to get it right was to build a pair of wings, see what comes out and adjust the manufacturing process accordingly.

The composite skins are made of 2mm Airex sandwiched between 2 layers of 50g/m2 fiberglass, with a strip of peel ply for the hinge line. Everything was vacuum bagged and put in the oven for curing at 60 deg C.

All the parts for the internal structure were laser cut; we used 3mm liteply for the ribs supporting the wingtube and 6mm balsa for the main spar. These parts were considered critical so they were carbon laminated, which added quite a bit of weight. We also added a few strips of unidirectional carbon between the main spar and the wing skins. All the other parts were made of 2.5mm balsa.

The internal structure alone was 140g, which made it clear from the start that this pair of wings were going to be heavy, but we decided to build them anyway and use them for testing.

A few images of the wing internal structure:

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Re: AUDAX

Publié : 24 août 2014, 16:11
par jclaude
Waouh! Very interesting subject!

I'm not a great fan of full composite structure, but, I'm very interested to follow, and learn, the latest technology.

Regards.

Re: AUDAX

Publié : 24 août 2014, 16:45
par fabien drouet
Par curiosité, pourquoi cet a priori sur le full composite ?

Re: AUDAX

Publié : 24 août 2014, 17:13
par Bloodhound
Fabien,

The foam and balsa wings have the advantage of being very light, but because of the hot wire cutting technique for the wing core, as a designer you are limited to a polygonal shape for the wing. Since i wanted my wings to have curved tips, i had to choose between built-up, balsa structure wings or composite construction wings. At that time i was quite busy with traning and contests so i had no time for designing a balsa structure wing; i also had a good offer from a friend for CNC cutting the mold plugs so i thought why not...

The stabs came out at 104g which is a pretty good weight for composite construction. As expected, wings are quite heavy (~496g) but i can use them for flight testing and we have plenty of ideas where we can save weight, so i'm sure we can achieve the target weight with the next pair of wings. The elevator is already cut and the peel-ply hinge seems very good.

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