Vertical Power is featured in the March 2009 issue of KITPLANES magazine. Stein writes about engine monitors, and VP is included because it can display engine gauges and alarms. But its real power is in power switching and pilot workload reduction! Click here to read the article.

 
When Mark Castle-Smith decided it was time to redo his older panel, he wanted the latest avionics suite in his RV-7. Mark's plane includes a Vertical Power VP-100, Fadec controlled engine, and three AFS EFIS/engine monitor screens.



The center console houses a Garmin 530 and a few backup switches.
 
The engine is fitted with two alternators and two batteries for power redundancy, particularly as the engine and whole aircraft are electrically dependant. Mark said, "I wanted a simple way to manage both alternators, simplify wiring, provide integrated backup circuits and automatically provide power monitoring and alarms. The VP100 fitted the bill!"

The trim is controlled by Vertical Power from switches on each of the sticks.

The VP Control Unit has eight inputs that are active when grounded, and two inputs that are active when at bus voltage. These inputs can be use to trigger annunciators, run the trim or flaps, start the engine, and other functions.

 

The bus voltage inputs are useful for:
- monitoring aux battery voltage
- external starter switch input
- starter engaged annunciator

That's three functions but there are only two inputs. The first two must be wired to the bus voltage inputs, but we can use a logic inverter to generate a ground signal when the starter is engaged. This can be wired to any of the eight ground inputs. For pictures and info, click here.

Many experimental aircraft today use electric trim motors from the Ray Allen Company. Along with the seemingly simple task of installing the trim motor comes more complexity and questions.

 

How do I show trim position?

How do I make the trim less sensitive at speed?

How do I wire it for the co-pilot and pilot?

What about runaway trim? 

How do I run them in a 28v system?

 

 

 
The Ray Allen trim servo (models T2-7A-TS, T2-10A-TS, or T3-12A-TS) has five 26ga wires, as shown in the diagram below:
 

 
The trim motor itself is driven by the two white wires. It does not matter how they are connected, as the polarity can be changed in the setup menus. The direction of travel is controlled by reversing the positive and negative connections to the trim motor. This is done conventionally using switches or mechanical relays, but is done in the Control Unit with solid-state circuitry. Therefore, no external relays or switches are required between the trim servo and the Control Unit
 
The position sensor uses three wires to determine the position of the sensor within the servo:
white/ orange - connect to ground.
white/blue - connect to a steady reference voltage.
white/green - the voltage on this wire changes as the servo moves.

The three wires are connected within the servo to a potentiometer. You can simply run all five wires from a servo directly to the VP Control Unit.
 
Then, you run wires from the pilot's and co-pilot's trim switch (typically a coolie hat on the control stick) directly to the Control Unit. No external relays, black boxes, or indicator lights are required for trim wiring.
 
These servos are designed to run at 14 volts, and the VP Control Unit provides regulated 12v power to the trim motors so they can operate safely in 14v or 28v systems.
 
The VP Control Unit now knows the trim input commands from the pilot and co-pilot, trim position, and has the ability to drive the trim motor. From that, it provides runaway trim protection, variable speed trim, trim position display, "trim running" indicator, management of conflicting inputs from the pilot and co-pilot, and backup trim controls.
 
That's one example of what we mean when we say "simpler wiring, more features."

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