Common troubles
Take off
Climb pattern
Distance task
How to turn
Model setting
Duration & Landing
How to use 1750w/min
Common troubles
F5B Aerodynamics and force analysis
Motor & Propeller
How to judge and it's equipment
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All the trouble I had and how could have avoided


What happened???? Just before the start, I turned on the switch and no ailerons and flaps were moving.
Why? The servo connector was disconnected from the receiver. Maybe accidentally disconnected when putting the battery in.
The wing servo connecter was connected upside down.
How to avoid the same problem. Connect all servos to the receiver, then cover it with a heat shrink tube.
Connectors should be clearly marked.

What happened???When I turn off the motor it made a big noise and the motor wouldn’t run afterwards.
Why? From impact of the brake, the motor mount came off.
The impact from many landings made the motor mount lose.
How to avoid same problem
Check motor mount after each flight.
You should insert a hard form block under the motor or ESC.
This will prevent movement of the motor at the landing.

What happened? No down elevator but everything else works.
Why? Elevator horn came loose. Damages from past landings
How to avoid same problem
Check all linkages and servos after each flight.
Similar problems happen with loose elevator servos.

What happened? Propeller flew away
Why? Didn't tighten spinner screw enough.

What happened? MY THUMB flew away
Why? Didn't connect battery in right direction, plane flew backwards when I threw the plane, and I lost my finger.
Go look for finger in the grass
Sew it back on.
This is no joke. In 92 WC at Holland I was helping our team mates start. Those day we were still useing brushed motor.
He didn't notice he connected plus and minus wrong way!!!
I asked him to turn for a second before start but he didn't want waste good enegy. This won't happen in todays ESC which has many safty program built into it, but be careful those 7000rpm carbon blade can do big harm to you or your friends

What happened? I noticed a very slow aileron response during the power climb stage. I turned off the motor immediately and aileron response got a little better but it still feels like something is wrong so I decided to land. It fell out of the sky when I pulled the crow brake on the final.
Why? One of the aileron connector was accidentally disconnected from receiver. The other aileron was working so it explains there were still some role controls. There is no hope for control when you pull the crow brake with one aileron.

What happened? Motor will not turn on at the start.
Why? Opto cuplers chip from limiter was damaged by pressing between fuselage wall and battery.
How to avoid same problem Relocate opto cupler to a safer place.

What happened? Motor will not turn at the start.
Why? Connector from ESC to limiter was upside down or in the wrong place.

What happened? Motor will not turn at the start.
Why? Motor channel’s servo range was too short. Increase it to 125%

What happened? Propeller didn't stop in flight, and all control failed.
Why? ESC was burned by overload and at the same time, it burned the wire to the receiver and made a short circuit.
How to avoid same problem Use opto cupler cable between ESC and receiver.


Always check all the connectors and linkages before the flight.

Way to Crash

What happened: Receiver battery only took 40mAh of charge and pilot thought it had
"false peaked", so hit charge again.  Receiver pack only takes 14mAh, so pilot decides that the pack is already charged.
Model stopped responding after 10 minutes into flight and goes into vertical dive from 150m to the ground.
- one propeller blade, the tailplane and the Unilogger survive the crash - all else is damaged beyond repair except hopefully the motor.
Why: Receiver pack is old (5 years) small in capacity (350nAH) and has developed high internal resistance, so does not accept a full automatic charge.
How to avoid same problem: Either:  1) replace Rx cells regularly, 2) give older packs a regular full cycle to test capacity or 3) go to a 2S LiPo Rx pack with a linear regulator.
by Raymond Pike