Saturday, 20 August 2011

Lets make a simple air-frame from polyester resin

I've been experimenting with plastic for radio controlled air-frames and they've been quite good, save for when you crash it and have to rework an entire section. So I decided to look around and see what composite materials are available to me. It was interesting to find fiberglass and more importantly polyester resign. So I decided to get the resign and skip the fiberglass for cost optimization reasons (I know,I know a euphemism). For the material to be hardened I went for good old fabric! But I need a frame to support the fabric, so once more I made a plastic air-frame and covered it with the fabric. Then I applied the fiber glass and, well, lets see...
First, I needed a set of wings and a fuselage. Using light enough plastic, I whipped up some wings and a simple fuselage using soda bottles and flexible plastic sheet. Below I am also making provisions for the brusjless outrunner that will propel the RC plane.

To make things interesting, I decided to make the wings delta, and use a front canard, like on Burt Rutan's design (the man's a genius)

Crude as it looks above, it worked out well in the end

Here's a better pic at the delta wing

Now I added the front canard and were ready for the canvas

Doesn't look too promising, but give it a chance....

On the next blog, the resign application, sanding, and spray painting, then attach the rudder. Stay tuned

Tuesday, 14 June 2011

Planes that Fly Themselves!

I am fortunate to have received an ArduPilot Mega from Metanomy (!

I gently (yeah right!) opened it and revealed.....
...and quickly went to work to assemble it....


...yeah yeah, female headers instead of male headers!! Not to worry, potato tomato

then programming! And its all good. Later, a little show and tell on how it works!

Thursday, 9 June 2011

Clutter or research? You decide!

I'm still battling with making a good Electronic Speed Control for my three brushless motors! My main issue is the transistors I am using, and my microcontroller! I am using a good trusty and reliable MSP 430 LaunchPad I got from Dan, who also gave me the three brushless motors as well as other goodies! So the micro-controller is a low power device (good for battery life, hard for switching power transistors), and I therefore need a pull-up transistor... So ....

I am using as usual the power supply from an old computer, and some power transistors. I am using a smaller 2N5551 trusty transistor to pull up the 3V source from the MSP430 to 12V for the power TIP142 transistors (feel free to stop me anytime, I'm a novice at electronics!)

In the picture you can also see one of the brushless motors!

Through this research, I am learning a lot of lessons in electronics and how better I can integrate my lessons to the Flying Thing! Eventually I will get an ESC for my purpose, but there are no lessons learnt from getting one right away! Not to mention the cost of acquiring one!

More clutter later!

Wednesday, 8 June 2011

Airplane design

When designing the Flying Thing, I did a quick and dirty whip-up of what I thought would fly, hence the name Flying Thing! This is undesirable, and you don't need an aeronautical engineer to spell looming doom somewhere along the corner!

My next design is well researched, and I am still in the process of identifying suitable airframe based on the characteristics I seek: Endurance, payload, service, speed, you name it!

Obviously the key is always cost: Keeping it low that is!!

From above you can see (not the clutter I hope!) the Flying Thing's general design, initially had a t-tail. This is the conventional tail most aircraft have, though of late I've come to realise there's nothing conventional where aircraft are concerned!

I've now fitted the flying thing with a v-tail, after a crash left the t-tail smashed and badly damaged!

Now you can see clearing I was following no design, just experimenting! You will have a lot more fun if you just have it without formalising your fun! Of course observe general laws of physics where you fun's concerned!

Have a safe flight!

Make do with the electronics available to you

I am learning new things everytime I work on the Flying Thing prototype. Though scarce are the necessary electronics, I am making do with what is available, so as to prove concepts early enough prior to development of a stable and working monitoring aircraft.

 I received three brushless motors from Dan, and I've no way of making them work: I have no Electronic Speed Control (ESC). So I've embarked to built one using transistors. photos below.
The photo above.... I am using an old laptop's parallel port to fire transistors: Three half bridges (six transistors) to generate the required 3 phase signal....

Friday, 27 May 2011

Monitoring Wildlife using Unmanned Aerial Vehicles to boost conservation efforts in Kenya

In the beginning: what started out as an investigation into "Flying Things" leads to conservation efforts...

 project boilerplate

I started out to see if using locally (Nairobi) available materials it was possible to develop an Unmanned Aerial Vehicle (UAV). As it turned out, it is quite possible to do so, but the challenges are countless: Electronics, programmable logic, you name it!
UAVs are not that common in Africa, though their application in Africa would be crucial for our development. When developing the Flying Thing, I've had several applications in mind, but the most important has been boosting Wildlife Conservation efforts in Kenya.

Tourism is key in Kenya, and accounts for the largest share in the GDP (I stand corrected! :) ). There are numerous wild animals in large reserves and parks that need protection from threats ranging from poaching to wild bush fires. Wildlife Conservation is therefore necessary to ensure continued survival of various species, some endangered, through provision of a monitoring platform at an affordable cost.
Using a UAV designed and developed for Wildlife conservation will see an enhancement on monitoring and control of the threats mentioned, leaving happy animals (and tourists :) )

I started by using plastic sheets and PVC pipes and whipped up this....

Its a simple but practical design. The yellow tube is the kind used for drainage water. I used my daughters stroller wheels for landing gear, and I am using side mirror motors as servo motor to actuate the control surfaces: Flaps, radarvators. Initially the Flying Thing had a conventional t-tail, but a crash lead to adopting a different tail. More on that later.

Usually to test I tow the Flying Thing. I use a van to do so, and usually use a road section currently under construction on Thika Road to avoid any traffic disruptions. When towed it unfortunately swerves from left to right owing to no steering and I have to move the van accordingly to compensate! You can imagine how dangerous that is!! Its all worth it when it glides though! I am looking to fit an engine to stop the towing.

 Here are some more pics...

...notice the nose of the Flying Thing. Someone on diydrones suggested I put a soda bottle :). Great idea! I am planning to fix a gasoline engine for more power and to enhance endurance: Gasoline is better than electric where endurance is concerned, as a lipo battery lasts about 10 minutes!!

...early construction showing the frame. Notice bottles holding it in place to allow PVC bonding agent to congeal!

.... trying out the electronics... I am powering it using PC power supply, bottom left on image!