Electric Stunt => ESC Settings => Topic started by: Motorman on April 24, 2016, 10:23:03 PM

Title: Launch
Post by: Motorman on April 24, 2016, 10:23:03 PM
Why do people have someone hold the plane until it spools up to full speed then release? Are they just use to that from the glow engine days?

My helper holds the plane until the prop starts to move then releases. The plane moves slow at first then speeds up and takes off.

I never used a helper until someone at a contest told me it's a rule or something so, I got use to taking off from a slow wind up. To me it's a waste of battery power to hold it back. Is there a down side or just personal preference?

Title: Re: Launch
Post by: Howard Rush on April 25, 2016, 03:22:30 AM
I think it's preference.  Some people have the helper go away as soon as they pick up the handle. It's legal as long as one person has ahold of either end of the lines.  I think folks wait for power to come up because then the takeoff thrust is always the same, making takeoffs more predictable than having RPM ramp up.  Because electrics reach full RPM on the ground, the torque can make takeoffs sporty with either prop rotation direction. I take off with constant, reduced RPM, then have it go to full power after a lap or so.     
Title: Re: Launch
Post by: Tim Wescott on April 25, 2016, 10:20:04 AM
I've also heard from folks who practice on grass that they prefer to have full power from the get-go because when the surface is not ideal a full-power launch is more predictable.

If you always launch off of decent pavement this wouldn't be an issue.
Title: Re: Launch
Post by: Joe Yau on April 25, 2016, 10:43:10 AM
I usually have someone hold on to it or use a stooge till the rpm is up when it is windy out..  its mainly to help the line tension on take-offs.  as sometimes the wind would shift directions during the launch and the line tension could get very light.. even free flight a little as I back up.  Otherwise I let it spool up by itself.
Title: Re: Launch
Post by: Igor Burger on April 25, 2016, 10:55:16 AM
Yes there is a safery rule for that as Howard mentioned.

However I found that since my helpers do not hold model with running motor, I have "magically" much less accidents on TO. The last I remember was TO in Poland WCh in deep grass ... and yes holder was present to "help" me :-P

So my way is to set my system for 4 or 5 seconds slow spin up and that gives smooth start and plenty of time react with handle (up/down as well as pull in case that model yaws or wheels "lock" somewhere berween rocks or in grass).

Holding running motor for full power on ground is not healthy for motor, battery, ESC and also abrupt strat can make troubles.
Title: Re: Launch
Post by: Howard Rush on April 25, 2016, 04:12:44 PM
There you have it from the Champion of the World.

A corollary is that many top stunt fliers forbid me to launch their airplanes