This thread is privately moderated by jjmouris, who may elect to delete unwanted replies.
Jun 03, 2012, 03:47 PM
Needs to do 52 legs !!
Verenigd Koninkrijk, Fareham
Joined Aug 2008
7,467 Posts
Here are some plots pulled from a very nice piece of software / programming made by Mr Magic. If you also want to be able to do the same and nicely overlap each climb of your flight then i suggest you get in contact with him.

You will notice in these graphs we are looking at the RX signal and the Power.

In this case the motor OFF signal from the RX is about 1230 us and full power is at about 1800 us. The signal is already rising a little before the ESC responds.

In this example the power is ramping up to just over 3000W before it then ramps a little slower up to 5000W when full power is reached and subsequently the power collapses further as the speed of the plane continues to increase and unloads the prop.

When looking at both sets of lines in the same graph, be sure not to get confused between the units given on the left and the right hand side. The RX signal is on the right hand side and given as A2 from the Unilog.

# Images

Jun 03, 2012, 03:48 PM
Needs to do 52 legs !!
Verenigd Koninkrijk, Fareham
Joined Aug 2008
7,467 Posts

# Images

Jun 03, 2012, 03:49 PM
Needs to do 52 legs !!
Verenigd Koninkrijk, Fareham
Joined Aug 2008
7,467 Posts
Effectively we have cut the RED triangle away. This is where the prop would likely have been partly stalled and the energy that you would have put in would have just gone to waste.

# Images

Jun 03, 2012, 03:54 PM
Needs to do 52 legs !!
Verenigd Koninkrijk, Fareham
Joined Aug 2008
7,467 Posts
The Futaba 12FG motor menu gives you several options to play with. I have highlighted in the respective colour what does what.

The first part of the ramp is called SPEED 1 and the second half is called SPEED 2. The number ranges from 0 to 27 where 27 is really slow and 0 is instantanious. Sensible numbers are between 10 and 24. I always use 10 for speed 1 and something around 22 for speed 2.

Then there is the switchover point. This is called (SPEED 1 > 2 ) and can be adjust from -100 to +100. Sensible numbers are around -25 to +10 and you should adjust in steps of 5 or 10% at a time.

Note that there is an IN and OUT speed given. You want to add a delay on the ON side only and not when switching OFF the motor.

Note that in some cases things may be reversed, it may also depend on if you use a throttle stick or a switch. Try the manual for the TX you have and/or experiment a little with a servo plugged into the throttle channel.

Page 103 of the 12FG manual reads MOTOR;
http://manuals.hobbico.com/fut/12fg-manual.pdf

# Images

Last edited by jjmouris; Jun 04, 2012 at 02:19 AM.
Jun 03, 2012, 04:21 PM
Needs to do 52 legs !!
Verenigd Koninkrijk, Fareham
Joined Aug 2008
7,467 Posts
The YELLOW lines is the first part of the ramp and is what keeps your prop from blowing up due to excess acceleration forces.

Be aware of WIDE BLADE RFM PROPS, these blades need a soft power up.

A slower ramp gives a smoother initial power delivery but wastes more time.

# Images

Last edited by jjmouris; Jun 03, 2012 at 05:01 PM.
Jun 03, 2012, 04:24 PM
Needs to do 52 legs !!
Verenigd Koninkrijk, Fareham
Joined Aug 2008
7,467 Posts
The second part of the ramp is the BLUE line and this is how long you want to take to feed the rest of the available power in.

A slower ramp means better prop efficiency and reaching max power further on in the climb.

It does however mean more work for the ESC.

# Images

Jun 03, 2012, 04:28 PM
Needs to do 52 legs !!
Verenigd Koninkrijk, Fareham
Joined Aug 2008
7,467 Posts
The switchover point is perhaps the most critical number of them all. It will raise or lower the GREEN line as shown.

A little adjustment on the switchover time will make a lot of difference as it will change the power at the start of the climb as well as effect how long the second ramp will last for. This is perhaps not what you would expect.

Different brands of TX/RX might make a difference here, so please keep in mind that my experiance has only been with Futaba.

# Images

Jun 03, 2012, 04:35 PM
Needs to do 52 legs !!
Verenigd Koninkrijk, Fareham
Joined Aug 2008
7,467 Posts
Here is one from a duration run.

You can see the switchover point is much lower and the result is a power curve that starts from about 1500W and goes up to 4900W over about 1.5 seconds. The power is cut shortly after reaching full power.

At no point during this motor run was the prop stalled.

The RX signal is about 1500us at the time of switchover between the ramps.

# Images

Last edited by jjmouris; Jun 03, 2012 at 04:59 PM.
Jun 19, 2012, 04:56 PM
Needs to do 52 legs !!
Verenigd Koninkrijk, Fareham
Joined Aug 2008
7,467 Posts
Here's one from todays results. Sergey Anashin's old plane back from 2009 with a new fuselage.

The graph also shows a free climb (ends short) and a huge duration climb, climb 1 is not shown.