Electronics Path

Taking some advice, I have done some soldering practice.

I purchased a new soldering iron to replace my 10yr old 15w iron, it is a Weller WLC100 soldering station. AMAZON Linkage - http://www.amazon.com/Weller-WLC100-Soldering-Hobbyist-Yourselfer/dp/B000AS28UC
I also picked up a couple of tips.

A trip to Radio Shack found me with a protoboard and a handful of IC sockets about 150 soldering points to practice with. A delivery from Sparkfun provided a “Simon” kit for soldering practice. The Simon kit went together without any problems in about 40 minutes while I was in a conference call. The practice was good. I don’t think I will have problems assembling the ArduMega.

A week ago I ordered a Skywalker, motor and ESC from BEVRC, as a bonus I added a Falcon EPO (Flying wing) to the order to get Free Shipping. It was a simple choice, $50 for shipping or add $50 to my order to get Free Shipping. The Skywalker arrived last Friday and the Falcon arrived yesterday. I will not complain about the shipping from BEVRC.

I am going to pick up the FrSky Module for my radio (Futaba 9C) with my next HK order along with a 5.8ghz transmitter/receiver combo.

Airframe Path

I am waiting on 10mm carbon fiber tubing for my tail booms. Yesterday 3mm and 6mm square carbon tubing arrived. The 6mm tubing will be used as the main wing spar and will be the step at the 50% mark for the KF3 airfoil.

I can start work on constructing Airframe #2 and should have the main wing done in a day or two.

Airframe #2 - Decisions and path options

I decided to follow parallel paths to my goal.

The first path is to continue development on my own airframe.

The second path is to use an off the shelf airframe to work on the electronics end of my goal.

Airframe Path:

As a part of my airframe development, I have decided to include my kids in the design and building process. They have an interest and I see it as a great learning opportunity.

I have drawn up Airframe #2, and made some design changes to make the design and build process easier. The main wing will have the ability to be removed to facilitate different wing layouts. I am also thinking about using a Carbon Fiber plate as a wing and tail boom mount.

Electronics path:

FPV will be 5.8ghz 200mw min.

I am debating about base airframes, Skywalker EPO or the Hobbyking EPP-FPV. Both have their strengths and weaknesses. Any comments about either are appreciated.

Another debate – Prebuilt Arduino Megapilot or build it myself. Price difference about $100, My soldering skills are decent but it has been years since I have worked at the level that the Megapilot needs.

One more debate - the FrSky DFT 2.4ghz Module for my Futaba 9C, I am currently using a Corona 2.4ghz Module.

Currently I am working on / waiting on the following items;

• 6mm x 6mm square carbon fiber tubing – To be used as a wing spar
• 3mm x 3mm square carbon fiber tubing – for various projects
• I have the plans for Airframe #2 plotted and Depron ready to be cut
• I am looking for a new source of Dow Fanfold, my local (50 miles) Lowes does not carry it any more
• Will be doing experiments with wing rigidity for various wing styles using 6mm Depron as a base, I see a few gliders in my kids future

Airframe #1 – Flight #1 – Who’s the U-boat Commander?

To make a long story short…Flew, crashed and ended up floating in the irrigation ditch.

After 2 weeks of 20 gusting to 50 winds I finally got a chance to fly… Winds were calm, a beautiful morning to fly.

The flight was airframe only, no payload.

I did a few “power assisted” glide tests to check trim and for surprises. The aircraft was a bit twitchy due to the enlarged control surfaces, I dialed in a bunch of expo to correct the problem.

The first part of the maiden flight held no surprises other than minor trim issues. ½ throttle provided more than enough power. The flight was going well, about 7minutes into the flight I got slightly bored…

Remember the wing strength concern? I did some medium power acrobatics, Loops and rolls and was having a bit of fun. I set up for a wide open throttle low pass and watched a rocket fly by. As I pulled into the climb out, I heard a popping sound as the wing buckled between the root and tail boom.

The next 30 seconds got quite “western” as I fought the flapping wing monster for a bit of control. I ended up bouncing off the bank of the irrigation ditch as a last resort to violating my hard boundary for the flight area. The aircraft ended up bouncing over the bank and ended up floating in the irrigation ditch.

Damage done:
Buckled wing due to high speed flight
Crushed nose due to ditch bank impact.
Broken wing tip due to recovery
Dead ESC due to water.

Things I learned:

It did fly and flew well when inside its airspeed envelope.

"Felt" very stable, makes for a good aerial photography platform

Very easy to build

Wing design has structural issues

Good payload bay volume

Did not do any payload capacity (weight) tests

The picture shows where the buckling occured.

Airframe #1 has been retired

Airframe #2 is on the drawing board

Design changes/additions for Airframe #2

Longer wing, 50 inches min.

KFM3 Wing

Better wing structure, 6mm x 6mm square carbon fiber tube as a full length spar

Strengthen or change materials for tail booms

 Strengthen the tailboom / wing interface

Airframe #1 - A starting point

I have spent some time looking at military and non-military “drones” and have determined a direction to move in for the airframe.

Currently, I am envisioning a twin tail boom airframe, a high mounted wing and a decent size fuselage.

As a starting point, I found the TiwnaxV2 http://www.rcgroups.com/forums/showthread.php?t=555476 of course I modified the design.

• I made the fuselage a bit “boxier” and left the nose and aft open for electronics cooling.
• I also laid out the fuselage so I could “score and fold” as part of the construction.
• I enlarged the control surfaces by 50%.

It took less than 2 hours from the time I printed the plans to a ready to fly airframe. Nothing like Depron and hot glue for rapid building.

Flight weight with no payload is 15oz, with payload 23oz. I did not calculate wing load, powered by a Grayson Microjet, 20a speed control and a 6x4 pusher – more than enough power for the aircraft. The airframe was setup with Throttle, Elevator and Aileron control without advanced electronics.

During the build I had concerns about wing strength, but ignored them as I have ideas for Airframe #2 to correct this issue.

 Airframe #1 Mocked up for final assembly.

My goals for airframe #1

• Potential structural issues
• Ease of assembly
• Weight and payload papacity
• Payload bay volume
• Will it fly

Once again Airframe #1 is the starting point and is no where near the end point.

As of this post Airframe #1 has been flown and retired. Results and observations in next Blog Post.

Once again, comments are welcome. 

I have been doing aerial photography with a variety of RC Helicopters for a few years. The biggest problem is short flight duration and pilot work load.

I have decided to design and build my own fixed wing aerial photography platform.

Here is my project goal; A fixed wing aerial photography platform with the ability to fly semi-autonomously (take off and landing pilot controlled). The camera will be mounted on a self-leveling mount to allow for photogrammetry and 3d point cloud generation, with a 10 minute minimum mission time.

A secondary goal is remotely operated camera mount that allows 360 degree pan and 90 degree tilt with a video downlink for camera aiming. FPV operation is also an option.

An ArduPilot Mega will be used as the autopilot. The ArduPilot does allow for self takeoffs and landings.

I have built, flown, crashed, and re-built RC Aircraft for many years and enjoy the hobby. This time I am designing my own airframe from the ground up. I will be honest I will borrow from other designs during the progression to my goal, in the end the airframe will be mine.

For the moment my my primary building materials will be Foam Core, Blue Core (Fan Fold) and Depron.

Comments and critisim are appreciated.

I hope you enjoy the trip

p.s. I am behind in posts here, and have flown airframe #1