Designing a Thrust Test Bench

One of my "Buyer Remorse" concerns is that the ESCs I ordered (Turnigy Plush 18A) won't have enough capacity for the combination of motor (NTM 28-26 1200Kv) and prop (8X4.5) that I also ordered.
I have searched the Internet for others using similar configurations but found in almost all cases they used a larger ESC (usually 30A).  When checking the specs provided with the motor it would appear that the motor/prop combo will draw no more than 10 amps at full throttle, so my 18A ESC should be plenty big enough...  or will it???

So, the only way to know for sure, short of building the Quad and seeing if it fails, is to test the components and develop some data.  To do that the motor has to be running with the prop on.  You also need some way of determining how much current the ESC is being asked to control.  In addition, it would be nice to measure the thrust provided by the motor/prop combo to see if it (with it other three brother motors) will have enough thrust to fly the Quad.  Most Quad gurus say that you need twice as much thrust as the Quad weighs for successful flight.  Based on my calculation my Quad should weigh about 1,000 grams (about 2.2 lbs) AUW (All Up Weight, the weight of the craft with everything installed, including the battery).  So, if my Quad weighs 1,000 grams I would need thrust of about 2,000 grams for good flight.  Since I have four motors, each one needs to generate at least 500 grams of thrust.  Based on info I have found I am expecting my motors to generate about 700 grams - but until I can test it, I won't know for sure.

Based on the info above, my test bench needs to be able to meaure the following:

• Motor Thrust at full throttle
• Maximum Current consummed at full throttle
• Voltage at full throttle (to calculate watts)
• Temperature of ESC and Motor during and after run

The bench also need to be able to support the motor as it runs and allow unrestricted airflow both in front and in back of the prop as it runs.  In addition, the bench should allow easy connection of motor, ESC and battery.  The bench also needs some way to control the speed of the motor (a throttle).

I found a great video on YouTube from the boys at FliteTest. They build exactly the Thrust Test Bench I think I need.  I will be stealing their design, with a few changes of my own...

To build the Thrust Test Bench I will need the following:

• 2X2 and 2X4 lumber
• A Hinge
• Corner Brackets
• Scale that reads in grams
• Watt Meter
• Terminal Block (to make connecting the ESC easy)
• Battery Connector
• Motor wire connector (3) (short wires with 3.5mm barrel connectors for easy motor connection to Terminal Block
• Servo Tester (to act as throttle - won't need to use transmitter)

Good news is I have everything I need other than the Hinge.

Here is my CAD drawing:

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