Getting started with Propellers

[Kryten 2X4B 523P]

Hi folks

 

Ive been tinkering with props and think I have enough info to get folks started on building a single engine light aircraft, as in the picture below.

 

Here's a pic in the assembly building with some pertinent info:

First up, engine:

These are massively overpowered for the application at hand. 

Under "Motor Size and Output" drop this down from 100 to 1. Yes, seriously. This will allow you to run the engine at max torque & RPM without it twisting the plane over. It should go without saying, but the more powerful the engine, the more torque it has.

Once set, disengege the motor, and set action group1 to toggle motor enagagement it, followed by action group Main Throttle with both Torque & RPM bound to it.

 

Prop Blades

Ive set these as static pitch, so it gives you an idea of how things work.

First off attach the blades to the engine and adjust so theyre flat faced when looking at them. 

Now set them to "Deployed" and the authority limit to -35.

At the bottom of the prop PAW window youll see theres two variants based on rotation. Pick the relevant one for the rotation of your engine - ie if the engine is going clockwise, set it as clockwise as above.

Edit / Update : with experimentation Ive found that you only need 2 blades on an engine when its power is set to between 1 - 4% of the original, max power output. Any more than that and the drag from extra blades means you get less power.  3 blades seem to operate in the 5 - 12% band (roughly). All testing done with the Type B prop. 

 

Youll still get some torque induced rotation when in flight.  To counter this I added a set of elevons, removed one from symmetry and set it to deployed at -9 on the authority limiter.

To start  going, reduce throttle to zero, engage motor with your action group binding, then throttle up. 

This little set up is slow, will take off around 45ms with a little encouragement from pitch control, and top speed is about 55ms. You will probably have to trim it out or set wings with a slight AOA depending on your build, but I took this over to the island runway fairly easily. 

 

Should be enough to get you all started, hope its helpful.

Edited July 27, 2019 by Kryten 2X4B 523P

[Kimera Industries]

Nice plane! Interesting choice to go with only one motor, I would've put two spinning opposite directions, but that's probably just the Kerbal in me saying moar thrust...

[Augo12]

I followed every step but I can't break 6m/s? What am I doing wrong?

Screenshot of my setup: https://prnt.sc/jdafIEM5eGHq