This step by step pictorial tutorial is intended to be a guide and point of reference for customers looking to build up a Stigg 195 FPV racer. This tutorial is designed to be supplemental to our assembly manual. Please read through the assembly manual FIRST. As with any build there are multiple ways to accomplish the same thing. One method may not necessarily be wrong, it may just be 'different'. Feel free to alter your own build procedure to whatever is best for your needs.
1. Motor installation - To save weight you can choose to use only 2 screws per motor.
2. ESC Preparation - It is important to protect the base of each ESC power wire set with shrink tubing. This portion of the wiring will pass through the arms into the center fuselage box.
3. ESC Installation - The ESC is installed to the side of the arm centered between the 4 socket head screws at the center fuselage box. Smaller ESC's can fit between the screws, but larger ESC's such as the Littlebee 30 AMP pictured below must be mounted on top of the screws. In order to make this possible you must double up or even triple up stick tape between the ESC and the arm. Use isopropyl alcohol on the surfaces prior to install. Pass the power, ground, and signal wires through the large circular hole in the arm at installation.
4. ESC to Motor Wiring - To get the maximum performance out of the Stigg its important to keep the amount of material in the line of thrust to a minimum. We suggest to run the wires which travel from the motor to the ESC under the arm. There are a few ways to accomplish this. A method which has worked well for us is to use 3 strips of shrink tubing spaced along the length of the arm. Motor wires should be twisted tight and fed through the shrink tubing strips. Once everything is in place heat the shrink tube strips to hold the wire bundle to the bottom of the arm and then use a strip of vinyl electrical tape near the ESC and the base of the arm to secure the wiring as it enters into the ESC.
5. PDB Prep - For this build we chose the Red Rotor RROSD. This is a PDB and OSD in one. Your specific wiring install requirements will be different if you choose a different PDB, however the general principles involved are the same for other PDB types.
First tin the various pads and pin header holes you are going to use. For this particular PDB its best to direct solder the Vtx and FPV camera wiring (+/- and signal) to the board. The fuselage box inner walls sit very close to the PDB edges and make using pin headers here impossible. Its smart to use a bit of hot glue at the base of your FPV camera wires to provide stress relief to them. The wire diameter on these is very small and repeated bending over time can cause them to break. Next solder your main lipo pigtail to the underside of the PDB. Use 14 gage wiring and use shrink tubing around the entire length of the wires. This protects the soft silicone insulation from damage. We cut our pigtail wires to 35mm in length. The length of these wires is personal preference.
6. PDB Install and Wiring - Install the PDB per the assembly manual. Temporarily use some M3 X 6mm long socket head screws to hold the PDB in place for the following steps. Cut the ESC power wires down and route them keeping in mind your RC RX must be mounted to the bottom of the PDB. Leave room for it! Keep in mind there isn't much space between the FC and the PDB so keep the wiring at the top of your PDB to a minimum. Make it easy on yourself and solder all ESC power wires to the bottom of the PDB. This will allow more space when the FC is pressed down onto the electronics stack. For our build we chose the Seriously Dodo FC which accepts up to 22 VDC. For this reason we soldered the power cable to the main lipo input pads on the top of the PDB.
7. Flight Controller, FPV Cam, Vtx, FPV Antenna installation - The flight controller needs to have right angle pin headers soldered to the bottom of the board into ESC input positions 1 - 4. Cut down the ESC signal wires to make a clean install and provide less excess wiring. Keep in mind you need to mount the FC down over the PDB so excessively long ESC signal wiring won't fit in this tight space!
There are a number of ways to get power to the FC. You can direct solder or use header pins. We chose to use header pins and a plug. The plug is soldered directly to the top of the PDB on the main lipo pads. The pin headers are soldered to the bottom of the FC.
We are running wiring from the XSR receiver to the top of the FC using pin headers, for ease of assembly / disassembly. However, you can also choose to direct solder if you like.
The Vtx and FPV camera wiring runs up the sides of the PDB/FC stack next to the fuselage box inner walls and connects into those components after everything is in place. Use double sized stick tape to mount the Vtx to the inner wall of the rollbar upright as shown below. Also use a single zip tie to lock it in place.
It is VERY important to use a zip tie around the FPV antenna and the rear rollbar standoff. This will relieve the antenna from taking crash loading. Loading is redirected to the rollbar instead.
8. Fuselage Box Bottom Plate / Velcro Strap installation - Make sure to bind your transmitter to your receiver BEFORE installing the bottom plate. The bottom plate is installed per the picture below. Run the main lipo pigtail out of the two slots at the corner of the plate. It is of vital importance you use a file on these slots and smooth the sharp corners down. Additionally, you should use shrink tubing along the entire length of both the positive and negative wires on the pigtail to protect them. Use velcro on the fuselage box bottom plate. All your lipos should have velcro on them. Velcro is important to help hold the lipo in place during flight.
The velcro strap can be mounted in one of two ways:
Option 1) Strap run through the two slots in the bottom of the arms, then through the slots in the bottom plate (as shown below). This is a very robust scenario. In this configuration any impact to the lipo is transferred into the arms and will mostly bypass the bottom plate. The downside of this configuration is over time the lipo strap will wear out faster due to the way it is mounted. Lipo straps are an inexpensive 'wear' item and cheap to replace!
Option 2) Strap run through the two slots in the bottom of the plate. This is a less durable scenario for your frame. In this configuration any impact to the lipo is transferred directly into the bottom plate, transferred to the 4 screws holding the plate to the standoffs, and then finally ending at the threaded interface of the screws into the nylon standoffs. If the force is high enough those nylon threads will strip. It not, they will hold. The advantage of this configuration is your lipo straps last longer due to the way they are mounted.
When the time comes to remove the bottom plate you may need to hold the 10mm long nylon standoffs (which separate the PDB from the FC) with small needle nose pliers. This will resist the standoff set from spinning.
Update 7-19-16: After further testing and tinkering we have determined a better way to run the motor - ESC wiring under the arm. Using one piece of shrink tubing is preferred. See pictures below...