Difference between revisions of "Mini Talon X-UAV from FPV Model"

Latest revision as of 13:41, 29 May 2017

January 2016

Contents 1 Introduction 2 General Specifications 2.1 Airframe and Controls 2.2 Power System 2.3 Build/Layout 2.3.1 A Few Last Views 2.4 Maiden 2.5 Mods 2.5.1 3D Print - FPV Cam Mount 2.5.2 3D Print - Skids! 2.6 Mods back towards stock 3 See Also 3.1 Project 3D Print Files 3.2 Vendors to use for this project 3.3 Comments? Questions?
	Ready for fun!

Introduction

Decided to try the Mini Talon as a way to get a medium range plane I could easily throw in my car. I looked at the Twin Star and the Floater Jet but finally decided on the Mini Talon because my large Talon is such a great flyer and it is relativley inexpensive.

General Specifications

Distributor - BangGood USA
Aircraft - X-UAV Mini Talon
Build Date - January, 2016

Airframe and Controls

I did decide to try a set of Digital servos mainly because I had them already. The linkage was changed to small Dubro 2-56 ball-ends on the Elevons because of the high miss-allignment btween the controll surface and the sevo arm travel.

Update: THe MKS digital servos were replaced because they were passing RF to the APM. I replaced them with Corona DS929MG's which seem to work very well.

Ball-end linkage on the elevons

For this build, I decided to try an RTFQ ReadyToFly 2.8 flight controller to save a few bucks and check out if they are reliable and as easy to set-up as my APM. I am using APMPlane 3.3 firmware.

For an OSD, I am running an RTFQ Micro MiniumOSD with my own character set.

For radio gear I am using a Taranis X9D+ with DragonLink V2 and a lightweight MicroRX Copter receiver.

Power System

For this build I chose a motor slightly larger than the favorite Sunnysky 2216/1250. Most who run the Sunnysky, overprop (9x6) it to the point of being dangerously un-reliable. I wanted to run a higher speed-efficient prop so a lower Kv motor was necessary and to get this all reliable I needed to go to a bigger stator size, 2221. The weight penalty for the larger motor is only 15g.

• Motor - Cobra 2221/16-940kv
• ESC - Cobra 33A Auto mode with brake set 'Hard'
• Propeller - Aeronaut Cam Carbon Folder - 9x7 on an Aeronaut 38mm/0 degree yoke
  
  

Prop Test Results

You can see by the test results, the 9x7 folder is almost a perfect match for the Cobra. Wide open throttle results in a static current draw of ~21A which leaves 4A of headroom with respect to the motors design capability. The maximum thrust is more than adequate and the prop speed is 15% higher than the maximum desired plane speed in level flight.

Update: In flight I am seeing a maximum current draw of 23A at 100% throttle during launch and a level flight cruise of ~3.5A @ 30mph.

Comparitive test with the chosen prop

Build/Layout

I won't spend anytime on pictures of assembling/gluing the foam bits together. I'll just show any mods and/or custom setups I did for this build. This starts with a simple layout with the Flight controller mounted on a plywood plate with rubber dampers attached between the wing support plates.

Flight Controller mounted on plywood plate with Micro MinimOSD servo-taped to the top of the case

Layout showing the Flight Controller, Micro MinimOSD, FPV power module and GPS

On the front I built an "FPV" module which includes the VTx, DL 1.3G Dipole antenna, a Storm32 brushless gimbal control board, an Effio camera, a two or three axis gimbal with Mobius camera and a two way camera switch.

FPV module showing the DragonLink 1.3G Dipole antenna and a Low Pass filter which will not be used

FPV module - Bottom view with VTx aluminum shield and heatsink

To power the FPV module I printed a mount plate for a 12v regulator, a 5v regulator and an RMRC LC power filter. All three components are mounted on foam tape with wire ties to hold them down.

FPV Power Module

Power module schematic

A Few Last Views

Side view with VTx antenna

To install the VTx Dipole I had to design a simple 3D printed thumb wrench which would fit through the hole in the fuselage.

DragonLink dipole and wrench

Using a process I detail in "How To - Create a Kevlar Skid Shield", I added 1.7oz Kevlar to the landing skid areas and over the battery strap.

It's all about Kevlar!

Front view showing smaller 2 axis Gimbal and VTx cooling ports - Ready for Maiden!

Maiden

The maiden went very well! After all the anticipation, the initial launch was as uneventful as its bigger brother, my full size Talon. It literally just floated out of my hand without any drama or surprises what so ever. Unfortunately I had to keep it LOS as the MinimOSD decided to not work. I'll get it all sorted out along with some initial PID tuning hopefully on a day with sunshine and no wind :).

Here's a video of the maiden flight. Because I had to wait till after sundown for the wind to get reasonable, I was running out of light pretty quickly. Enjoy...

Mods

3D Print - FPV Cam Mount

I decided to copy an RCG poster by mounting the FPV camera in the nose and below the deck. I am using a Seawolf Pixm board cam that is 38mm square with mount holes at 33.5mm. With that, I came up with this print for a mount:

Rear view of FPV cam mount

FPV Cam Mount Assembly

The rectangular hole above the camera is to direct some airflow down the back of the FPV camera for cooling as the Seawolf gets quite warm. It took a bit of creative foam carving considering there was some minor damage from earlier landings but it came out OK. I then added some PLA skids (next section) to better protect the camera.

3D Print - Skids!

After much destructive landing on rocky roads and general desert areas I decided to do away with the Kevlar and print up some "Bash Guards". The Kevlar did its job just fine but my conditions are extreme and my ability to land smoothly is, well, lacking...:D

So on my present MT which has the front hump cut down, I made a flattened version of a printable skid plate:

Flat bash plate

For my newly received $49 BangGood special (AKA: MT#2), I printed up what would fit without modification. The front skid weighs 23.5g (@ 40% infill for you 3D printer guys) the rear skid weighs 8.5g. Both conform almost exactly to the rounded shape of the Talon fuse so gluing will be easy enough (White tube, Zap Goo or Contact cement, etc.). Here are a pile of pics:

Off the printer (after clean-up)

It fits!

...and it conforms!

Rear skid right off the printer

After some Dremel clean-up and pushed onto the fin

The front skids are 2.8mm thick on the flat section and 2-2.5mm for the rest. The rear skid is 1.8mm thick along the center tapering down to 0.5mm on the edges.

Mods back towards stock

After more than 80 flights and many "Nose Jobs" I have decided to convert this mostly back to stock and make it a "Guest Plane" for when friends come to visit and fly with me. So, I have gone to a cheap NTM3530-1400kv motor, 30A ESC and 3S for the power set-up. I'll run it with either a 9x6 or 9x7.5 APCe prop depending on the efficiency or power needed. I've also put the stock deck back together with a printed flat cover, new Mobius mount and a $12 version of the HS1177 FPV camera. I also swapped out the DragonLink RX with a FrSky L9R 2.4 unit and the 1.2VTx with a 5.8. Here are some pictures:

New flat hatch cover, camera mounts and Eachine 5.8VTx

Went to an old M6n GPS and a printed antenna mount for the FrSky L9R

Replaced the old battery strap and toe hook with newer versions

Larger NTM motor and 9x6 prop

See Also

Mini-Talon on RC Groups

Mini Talon X-UAV Build Number 2

Mini Talon Noses

Project 3D Print Files

FPV Nose Cam Mount

Front and rear printed skids

Antenna Wrench

Vendors to use for this project

Ready To Fly Quads

R/C Dude Hobbies

Hobby King

Comments? Questions?

email me!