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Old Jun 07, 2011, 02:05 PM
Flying Shoe
theleetbeagle's Avatar
Ohio
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How Do I Simulate Single Engine Failure On Two Engine Plane?

I have plans to build a two engine plane similar to...well...anything. Like the Dynam Grand Cruiser.

I would like to simulate a single engine failure with the flip of a switch on my TX. How might I do that? Are there any devices made that can open/close a circuit at will like that? Made especially for RC?

Thanks.
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Old Jun 07, 2011, 02:10 PM
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United States, AK, Fairbanks
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Might be able to accomplish it with some kind of mixing... It might be really dangerous to do it by actually cutting the power to the ESC/motor, but a servo-controlled switch could do that. You'd have to get the ESC armed to get power back to the motor, which may not work too well...

But maybe if you have one ESC connected to the flap or retract channel with a 100% mix, you could kill it be hitting the switch. Heck, you could even do BOTH if you had one on retracts and one on flaps, with both mixed straight to throttle
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Old Jun 07, 2011, 02:13 PM
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OH WAIT....

I actually had a throttle-cut switch programmed on one of my planes as an experiment. It was exactly what I just described, a -100% throttle/flap mix (or something close; I don't remember exactly what I used). It worked perfectly, but the switch HAD to be set right before powering up the ESC or it would do all kinds of weird stuff.

Hmmm... so THAT'S where that idea came from in my last post
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Old Jun 07, 2011, 04:12 PM
Flying Shoe
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Ohio
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Hrm. If I understand correctly, you had the throttle of one motor on a separate channel, but mixed into the normal throttle channel (ie, ch3), which of course controlled the OTHER motor. So under normal circumstances ch3 controlled one throttle plus the mixed-in other throttle. THEN, you had the non-ch3 throttle on an on/off switch.

I think I've got it. Even if that's NOT what you did, I think it will work in my situation.

Thanks!
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Old Jun 07, 2011, 07:15 PM
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I was only running one motor, but the mixing could be set up so that the "flap" channel is also controlling an ESC, but it's mixed linearly with throttle. So yes, you're absolutely correct (assuming we both know what we're talking about, which in my case is very unlikely... ).

Also, for the love of Pete, test these things with the props removed I ate a big hole through my mom's tablecloth while setting up that kill switch
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Old Jun 07, 2011, 07:45 PM
Fueled by Arabica Beans
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Put a switch (rated at the proper current limit) in the middle of one of the ESC to battery wires and attached to a servo on an auxillary channel.
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Old Jun 07, 2011, 07:49 PM
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Quote:
Put a switch (rated at the proper current limit) in the middle of one of the ESC to battery wires and attached to a servo on an auxillary channel.
When it's time to turn the motor back on, though, he'd have to re-arm the ESC. Depending on the unit itself, that might require some kind of arming sequence with the throttle stick. Keep in mind that the other motor would be functioning normally, so that motor would be responding if, for example, he had to cycle the throttle stick. Even if it was just a zero-throttle delay period like the HobbyKing SS ESCs, that still means the plane would have to glide for however long it takes for the ESC to be ready to go.

The extra servo and the switch would also add weight...
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Old Jun 07, 2011, 08:13 PM
Fueled by Arabica Beans
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Quote:
Originally Posted by TP16 View Post
When it's time to turn the motor back on, though, he'd have to re-arm the ESC. Depending on the unit itself, that might require some kind of arming sequence with the throttle stick. Keep in mind that the other motor would be functioning normally, so that motor would be responding if, for example, he had to cycle the throttle stick. Even if it was just a zero-throttle delay period like the HobbyKing SS ESCs, that still means the plane would have to glide for however long it takes for the ESC to be ready to go.

The extra servo and the switch would also add weight...
What good is simulating an engine out with the ability to turn it back on.
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Old Jun 07, 2011, 09:11 PM
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Quote:
What good is simulating an engine out with the ability to turn it back on.
What good is a simulation if it puts you in exactly the same situation as the real problem?
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Old Jun 08, 2011, 11:57 AM
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you could just use a simulator and practice a single engine flying so you dont smash your plane
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Old Jun 08, 2011, 12:01 PM
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Where's the fun in that? Besides, learning happens much quicker in the real world when you CAN smash the plane
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Old Jun 08, 2011, 12:13 PM
Fueled by Arabica Beans
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Quote:
Originally Posted by TP16 View Post
What good is a simulation if it puts you in exactly the same situation as the real problem?
It's a good realistic one, that's what it is.
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Old Jun 08, 2011, 04:37 PM
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Assemble a GWS ME-262 with two 2028 3900K GWS motors snd two T-Bird 36 speed controls, won't happen right away but it will happen!
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Old Jun 09, 2011, 04:14 AM
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Norway, Akershus, Frogner
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Get one angry farmer with a shotgun try to shoot at one of your engines?

In a serious note: Are you sure ... really sure you want to do this? RC planes have allot of power for their size. Wich would mean that if you turn off an engine at over lets say 20% throttle you run a high risk to pull the plane straight into a spin you can't just throttle yourself out of. Especialy since the blades won't feather and would increase drag even more.

Other then that i think you might want to try to set up a system that prevents the motor/ESC from losing power. As the ESC will need time to boot and count the cells. Also you need to keep 0 throttle when connecting the battery / re establish the power.

The easyest thing i think would be to put a switch between the engine and ESC with a servo. Thatw ay you keep power to the ESC but just take out the motor, that should work.
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Old Jun 09, 2011, 07:05 AM
jrb
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Edina, MN, USA
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Mixing can do it; similar to using mixing to get yaw from motors via rudder stick.

Use different chanel for on/off.
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