Fuselage mould milling

Yep, it just started we are about to finally get our mould to laminate a fuselage structure.

But first we had to:

Design in a Catia V5, how to arrange material for milling, to avoid too much waste....

Then we cut a prolab into small pieces according to design above and stick them together in a proper way.

 

And finally we could move to workshop with milling machine. Of course on the way there we generated a CNC code for the machine....

So that's a result of 8 hours of constant milling and days spent over computer, in a workshop with hands on job... in dust and sweat :P Well we reckon that's impressive :)

Wings are alomst ready to fly!

We've just equipped the wings with servo actuators. It means more less that they are ready to FLY :D

 Now we need to wait until a fuselage will be ready...

Angle of attack and side-slip sensor

We managed to get into work a angle of attack and side-slip sensor, which we designed and build on our own. It sends first signals and processor is working fine, so check out very first screen of what it shows....

Video range test 1

We continued with test of video data transmission range. Here are some pics taken during a in-field work :)

First we made on our own, circular pattern vertically polarized antennas, adjusted to WiFi frequency, since that's interface we use to send video image.

First antennas to test (later we have plans to test a directional antenna and compare results)

Get ready and go!

In a car receiving video image. As you can see we used a standard WiFi router as a receiver. We have a preview of video trough web-browser. 

 

And a car sending a video signal, as a  transmitter we use video-server, like one that you will find here http://www.geovision.com.tw/english/Prod_GVVS12.asp

We connected a camera to that magic box, then putted a USB WiFi transmitter into it and it worked pretty well :) We hope for better range results with new directional antenna ;)

Tests of video cameras

We integrated whole system of video cameras and we started with test for obtainning a data transfer range and overall power consumption of whole observation system. 

Tests of parachute

We made first tests of a parachute to confirm results of a series of CFD simulations. It will help us to choose the best shape.

Fuselage

We are about to build moulds for fuselage. We decided to use a sandwich composite with aramid honeycomb core and of course vacuum technology.

That's how mould look like:

 Fig. 1 3D model of moulds

 Fig.2 Prolab

At figure 2 you can see a prolab material used for milling on CNC machine to obtain female moulds. It has many advantages, the most important one is that the surface of mould is ready to use right after milling, so it saves a lot of time, unfortunately it is one of the most expensive materials available.

Propulsion System

On 2nd of August we get equipment for propulsion system: propellers and engine. We decided to conduct wind tunnel tests to select best propeller for optimal energy consumption.

We chose Dualsky XM5060EA-8 engine. Which provides around 900 [W] of constant power.

Parachute Rescue System

Since our uav is going to land on a parachute, we started with PRS design. For the very beginning we used FloWizard software (from Fluent) to simulate flow around different shapes of parachute.

Few results:

Fig. 3 Flowpath

Fig.2 Vortexes 

Fig.3 Velocity distribution

Video cameras

Hi!

That's our concept for cameras arrangement:

One for observation of targets during the mission and one for pilot with on-screen-vision for presentation of navigational and attitude data

We get our video cameras. Both of them are standard analogue CCTV cameras. We chose them because of good quality/price ratio, which is quite essential in a student's project :)

Camera 1 (bigger one):

Sensor: 1/4" Sony CCD

Lens: MOTOZOOM, 3.9 ... 105.3 mm

Sensibility: 0.5 Lux

Resolution: 520 TVL

Angle range: 50° ... 2°

Optical zoom: x27

Functions: OSD menu, Autofocus

Camera 2:

 Sensor: 1/3’’ SONY SUPER HAD CCD II

Resolution: 600 TVL

Sensibility: 0,001 Lux

Lens:  3.6mm/F2.0

Angle range: 70° 

Stage 3 - composite laminating

In that stage, 2 weeks after we started so around 30th of July, we started with laminating of wings surface. We applied 0,8 [atm] vacuum to obtain perfect surface and results are seen at pictures below:

Stage 2 - strucutural elements

In next stage we used CNC milling machine to cut plywood ribs, which we glued into the core of the wing.

 Next step were wing spars. We used carbon fibres roving and pine wood. At photos below you can see how we did it.

We also added "shelfs" for servo mounting and sockets for pivots, to connect wings to each other

Stage 1 - Hot-wire cutting

On 10th of July 2012 we started with hot-wire cutting of a styrofoam  cores of wing.

Have a look: