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rahulsarchive committed Dec 3, 2018
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Expand Up @@ -2,7 +2,7 @@

The aim of this project is to develop an open source aerial mapping platform using standard hardware and to develop a workflow from data acquisition to data processing.

![open uav](Images/ICFOSS.png)
![open uav](../../Images/ICFOSS.png)

FOS UAV is part of the Drone Research Program by [ICFOSS](https://icfoss.in/) (International Center for Free and Open Source Software)

Expand All @@ -12,7 +12,7 @@ Most UAV's today are multirotors, they have the advantage of being able to hover

Fixed winged aircrafts fly on the principle of aerodynamic lift and are far more efficient at covering ground than multirotors. Even though they are considerably harder to design and build, they make up for with efficiency.

Our goal is to build a suitable fixed wing platform that can carry the necessary payload and provide usable data for arieal mapping. The craft needs to carry a good GPS system, a downward facing camera for taking images, and be able to fly missions autonomysly.
Our goal is to build a suitable fixed wing platform that can carry the necessary payload and provide usable data for arieal mapping. The craft needs to carry a good GPS system, a downward facing camera for taking ../Images, and be able to fly missions autonomysly.

Our constrains being, it must be simple to make, and easy to use. All the hardware and software are low cost and open-source, without sacrificing saftey and usability.

Expand All @@ -30,30 +30,30 @@ AUW: 870g
Power plant: 2212 1000kv motor (10x4.7 prop)

This is our first attempt at making a flying wing. This wing will be made from styrofoam and since a hot wire cutter is the most efficient way to cut foam, we decided to built a [4-axis CNC hotwire cutter](https://github.com/rahulsarchive/4AxisFoamCutter) to help us make the wing cores. Its been a blast making it, see the repo for the documentation.
![open uav](Images/V1.0/dw1.png)
![open uav](../Images/V1.0/dw1.png)

After a bit of reasearch on fying wings, we settled on the parameters and started working on the design.The wing will have a wingspan of 800mm, swept back at and angle of 30deg and have a blunt nose fuselange in between to carry all the payload. The hot wire cutter helped us tremendousely in cutting out the wing cores.

![open uav](Images/V1.0/hw1.jpg)
![open uav](../Images/V1.0/hw1.jpg)

![open uav](Images/V1.0/hw3.jpg)
![open uav](../Images/V1.0/hw3.jpg)

![open uav](Images/V1.0/asm1.jpg)
![open uav](../Images/V1.0/asm1.jpg)
For additional strenght we decided to do a composite on the wing cores with wood glue and paper towels. This gave us a hard and rigid outer shell which can take the impact of landings. This shell was coverd with a layer of packing tape to seal all the rough edges and then a layer of vinyl tape to provide some colour.

![open uav](Images/V1.0/asm2.jpg)
![open uav](../Images/V1.0/asm2.jpg)

![open uav](Images/V1.0/asm3.jpg)
![open uav](../Images/V1.0/asm3.jpg)
The wing is very light weight with the foam cores and has a tough shell to protect it in impacts. The motor mounts were laser cut on 3mm birch wood and joined to the wing with glue. Though originally desinged for a 2205 2600kv motor. In the end we had to go with a 2212 1000kv motor running a 10x4.7 prop.

We realized one problem when tried to balance the CG of the wing. There was not enough weight on the front to get the CG where we wanted, even with the bigger batttery the plane was still tail heavy. For the intial maiden we added bit of nose weight to bring the CG forward.

The maiden did not go successfully. It was very difficult to control and came down nose first. The wing was very heavy and barely had enough thrust to get it flying. Especially with all the drag from the large front bumpers. We realized that even though we designed for a 30deg sweep angle, after construction, the sweep was around 24deg. This pused the CG point forward and there was not enough weight in the front to balance it.

![open uav](Images/V1.0/asm4.jpg)
![open uav](../Images/V1.0/asm4.jpg)

we tried putting a flight controller in it to help in stablizing the craft. We were able to fly with the help of flight controller. The model is still too tail heavy and the plane does not have enough thrust to carry the extra nose weight.
![open uav](Images/V1.0/ph1.jpg)
![open uav](../Images/V1.0/ph1.jpg)

### Note

Expand All @@ -68,9 +68,9 @@ we tried putting a flight controller in it to help in stablizing the craft. We w

This is our first version of our wing using a KFm6 airfoil. The center fuselage is designed to carry a camera, two 2500mah lipo, the flight controller and the motor. It needs to be strong to survive impacts and protect the electronics.

![open uav](Images/V1.5/dw2.png)
![open uav](../Images/V1.5/dw2.png)

![open uav](Images/V1.5/dw3.png)
![open uav](../Images/V1.5/dw3.png)

We decided to keep this on hold until we test out the KFm airfoils on more simpler airframes.

Expand All @@ -86,32 +86,32 @@ Power plant: 2826 1500kv motor (9X6 prop)

Learning from our previous wing build, we decided to increase the sweep angle to 35 deg to push the COG backwards, so the wing would balace with less weight upfront. This wing will be an all foam construction and will accomodate a battery plate to house all the electronics.

![open uav](Images/V2.0/nw0.png)
![open uav](../Images/V2.0/nw0.png)

The wing will have six layers in total, two base layers and two KFm steps on top and bottom. With all the extra foam, the construction will be heavy.

![open uav](Images/V2.0/nw01.png)
![open uav](../Images/V2.0/nw01.png)

The motor mount is designed to sequrely hold on to the layers of foam. Its a minimal design and provides resonable sturdiness when attached to the foam.

![open uav](Images/V2.0/mm1.png)
![open uav](../Images/V2.0/mm1.png)

The two locking clips on the top and bottom, provides assurance that the motor plate won't come loose from the assembly. The entire part is covered in a syntetic resin to provide strength and resist vibration.

The 3D model is converted into **DXF** format and made sutitable for CNC cutting. The design is cut on **Shopbot PRS alpha 3-axis CNC mill** using the [CNC Drag knife](https://github.com/rahulsarchive/cncdragknife) we designed.


![open uav](Images/V2.0/cut1.png)
![open uav](../Images/V2.0/cut1.png)

We did not have depron foam available with us, so we decided to use **Coroplast** for the construction. It's heavier than depron but is also much stronger, it can take impact well and binds well with hotglue and syntetic rubber adhesives.

![open uav](Images/V2.0/nw1.jpg)
![open uav](../Images/V2.0/nw1.jpg)

The final assembly with all the layers stuck together.

![open uav](Images/V2.0/mw3.jpg)
![open uav](../Images/V2.0/mw3.jpg)

![open uav](Images/V2.0/nw2.jpg)
![open uav](../Images/V2.0/nw2.jpg)

The maiden went beautifully, the KFm performed well, the wing resisted tip stalling and glides like its on rails.Because of the sweep, the COG balances prefectly with a 3800mah 3S lipo. Takes off at about 70% throttle and cruises at 50%. Since we used coroplast, the wing is a bit heavy for a 1m wing span model, as such needs to fly a bit faster to maintain altitude.

Expand All @@ -136,22 +136,22 @@ Power plant: 2826 1500kv motor (9X6 prop)

We decided to built a bigger and lighter version of the wing, it will have lighter wing loading and can fly more slowly.

![open uav](Images/V2.1/v21b.png)
![open uav](../Images/V2.1/v21b.png)

The wing is made from **5mm depron** sheets, depron is much more easier to work with than coroplast. It is lighter and can be bend when heated. The wing is made by stacking 4 layers of depron sheets to from the KFm4 airfoil.
![open uav](Images/V2.1/tm1.jpg)
![open uav](../Images/V2.1/tm1.jpg)

The layers are stuck together with hotglue and syntetic resin. There is thin laminating layer on the depron which provides strength, if you remove the layer by sanding, it will weaken the structure.

![open uav](Images/V2.1/tm2.jpg)
![open uav](../Images/V2.1/tm2.jpg)

We laminated the wing with black packing tape. The tape provides the strenght for the model, we used a thicker tape and the weight of the model increased by 100g. Light weight packing tape would be a better choice.

![open uav](Images/V2.1/tm4.jpg)
![open uav](../Images/V2.1/tm4.jpg)

The stripes are added for effect. It does make the wing look cool.

![open uav](Images/V2.1/tm5.jpg)
![open uav](../Images/V2.1/tm5.jpg)


The wing flies beautifully, it glides forever. Very good slow flying characteristics and controllability. When flying slow wind does push the craft around, buut once you get some speed it flies like an arrow. Very little relex on the elevons was need to keep it level.
Expand All @@ -176,33 +176,33 @@ Power plant: 3530 1400kv motor (9X6 prop)

This will be a slightly bigger wing than the previous one, we want it to carry a downward facing camera for arieal mapping purposes.

![open uav](Images/V3.0/1.png)
![open uav](../Images/V3.0/1.png)

![open uav](Images/V3.0/2.png)
![open uav](../Images/V3.0/2.png)

It will be a heavier version witha slighly longer wingspan and reduced sweep angle to bring the CG forward as we will be putting a 6000mah (2X3S) battery and Gopro in the front.

![open uav](Images/V3.0/5.png)
![open uav](../Images/V3.0/5.png)

The battery plate with the provisons for attaching two Gopro cameras, one facing downwards and other facing forwards. It will support 2X 2600 mah batteries, a flght controller and receiver.

![open uav](Images/V3.0/3.png)
![open uav](../Images/V3.0/3.png)

The design made ready for cutting in the CNC machine using a Drag Knife.

![open uav](Images/V3.0/4.png)
![open uav](../Images/V3.0/4.png)

The parts are split apart and arranged to provide the most economical use of material and provide strength where needed and reduce weight were not needed.

![open uav](Images/V3.0/6.png)
![open uav](../Images/V3.0/6.png)

The motor plate with the larger base and stronger supports for the bigger motor.

![open uav](Images/V3.0/v31.jpg)
![open uav](../Images/V3.0/v31.jpg)

The wing is fitted with the MatekF405 flight controller, an Frsky S8r radio, SIK radio telemetry, Skywalker 60A ESC, DYS 3536 1100Kv motor

![open uav](Images/V3.0/v311.jpeg)
![open uav](../Images/V3.0/v311.jpeg)

The wing was big and heavy, but the material choice was poor, the coroplast was sagging at the ends, the frame as a whole is not rigid enough and the flight chracteristics were not as good as expected, its a bit tail heavy.

Expand All @@ -225,31 +225,31 @@ Considering all the things we learned from the previous model we decided to buil

Cutting Depron in Shopbot CNC mill. The frame is made form multiple sheets stacked on top.

![open uav](Images/V4.0/02.jpeg)
![open uav](../Images/V4.0/02.jpeg)

The arrangement showing how the pieces fit together.

![open uav](Images/V4.0/1.jpeg)
![open uav](../Images/V4.0/1.jpeg)

The model after assembling.

![open uav](Images/V4.0/2.jpeg)
![open uav](../Images/V4.0/2.jpeg)

Finishes sticking all the parts together and made a fuselage out of depron for housing all the electronics.

![open uav](Images/V4.0/5.jpeg)
![open uav](../Images/V4.0/5.jpeg)

The Elevons sanded to give the airfoil shape. and attached to body uing Nylon hinges.

![open uav](Images/V4.0/6.jpeg)
![open uav](../Images/V4.0/6.jpeg)

The finished airframe with a painted body and tape covering to protect it from damage.

![open uav](Images/V4.0/v4.jpeg)
![open uav](../Images/V4.0/v4.jpeg)

The wing flies well, it needs a 5000mah battery and a Gopro in front to balance out the CG but once its balanced, it flies well, good glide slope and stall characteristics. The KFm6 seems to work well with this airframe.

![open uav](Images/V4.0/v41.jpeg)
![open uav](../Images/V4.0/v41.jpeg)



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