After my last to planes I still had some depron left. I decided to build myself another plane instead of throwing it away or keeping it for repair scrap.
I had already came across a free pdf version of F-117 and the choice were easy. After transforming the pdf manual into paper with a little printer help, I realised the plane were to advanced. Which is not really necessary in my opinion. This resulted in what I would call a 50/50 build. I started the nose as it should be, but shorted the back down quite allot. I ended up only using the paper as line-up before adapting the pieces were I wanted them, using eye sight.
This article will have an overview of our school project (term 2/6). There are three heads on my group. Our goal with this project is to make a mechanical hand which can move it fingers like a real human hand, electronically controlled. Even point at, pick and crush things!
Before we decided what project we wanted to do, we had several ideas. A sensor based 4wd vehicle to mention one of them. After setting our goal on making a mechanical hand we did our research on google search/images. We only found a single hand (image below) which seemed something we could do in our time, among many other professional vendors.
It is required by us to setup a budget and plans for the rest of the project. All groups in my class needs to be finish by week 21 when the presentation is.
Me and my group are finish developing the hand and making it. We also got our plans for each week ready. Luckily, we reached our milestone for this week, were we wanted to figure out signal’s need for the RC-servos.
The hand is going to be drifted with five Futaba 148S servos, they cost about $19 each and provide 4.1KG of torque with 6.0v and a twist time of 0.19sec/60 degrees. So far, our budget is on $94, but it may increase by a few bucks due to some small components we might need.
We are still working on the sinew/rod’s before installing servos. We might just clean it for all welding points as well.
Update #1 We have now figured out the servo signals and created a physical servo controller. We are using the 555 timer, two actually, because we had an issue with only using one. It didn’t create a stable output before 30 seconds after start. The
surrounding components, capacitors and resistors are our variables, changing the signal length.
We also did make a counter using two J/K FlipFlops and a dmux to convert the signals.
The circuit’s for this hand is so complex, that we decided to program it all into a Altera card. Logic scheme will be available later when we have completed the project.
I’ve have been building this plane in parallel with the F22. Extra 300 is a free PDF-plane from rcpowers.com
The idea with this plane is to use a motor with variable pitch. These setups are rare and a bit more expensive than other powers systems. I will also have to install another servo to be able to change the pitch rate on the prop. 4D motor features a hollow motor shaft and I bought a set from hobby-lobby.com some weeks ago. The motor mount coming with this motor is designed for 3mm depron and I’m using 6mm depron. This is my first real problem on this plane so far. Will probably grind the front down to 3mm to be able to mouting the motor.
Update: the 4D motor were to weak for this plane and failed pretty quick. It`s now run as a pure 3D plane, even as this it`s way to flexible. I should have stiffened it of with more carbon.
Another mistake I did was making the plane in 105% size, 5% bigger than the orginal. If I were to build this again it would be 80%.
Two days ago, I managed to get my hands on 800×1200x6mm depron sheets locally. I only had to pay 207NOK or $30, if you wish. These sheets are god for 3-4 planes. I almost got two planes in one sheet where the Raptor was cut in one piece.
Yesterday I received my package from readyheli where there was two receivers and four 11.1v 850mAh kongpower batteries I tend to use on these planes. More on my second plane in another post.
Specifications for this plane will be updated when I deside the electronics for it.
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