kevinthoele

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Hey Guys and Gals,

Anyone know how to program for twin so you can start one then the other and finally switch over to both on throttle stick. Someone mentioned they saw this.

3 position switch first position let start number one engine number two in hold.
Middle position start second engine first engine at idle.
last position both engines working on throttle stick.

Sounds awesome if someone can help me with the mixes.
Thanks

Billy

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I used to start them manually through the gsu. That way I could restart one and not have to shut the other one down in the process

Billy

CraigG

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What brand of turbine? JetCats have a method of starting one at at time from the tx via the throttle trim/throttle position. It would be neat if there was a way to do it with mixes but I'm with Billy in that I prefer to start them manually with the GSU.

Craig

George

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I don't know if it would work EXACTLY as you described, but it would be possible to use the mixes if you use two separate channels for the engines. I'd love to give it shot if I had access to a 12X.

I have always started my twins (non-Jetcat) together with the ability to reset each engine individually in the case of a failed start on either engine.

kevinthoele

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The engines are 2 K80's. And yes would use 2 channels for throttle as mentioned earlier.

Thanks for any help.

CraigG

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Stan Caussel did something similar with his MIBO A-10. He describes it somewhat in this thread: http://www.rcuniverse.com/forum/m_69...17/key_/tm.htm

It's post #401 at the top of the page.

You might want to pm Stan (RCU name STAN-CAUSSEl) to ask him how he did it, although I think it was a radio other than a 12X.

PS: Kevin, are you going to MS Afterburner? If so, look me up at the Georgia Jets tent and we can talk twin engine operation.

Craig

Jgwright

Hi Kevin

I may be able to help you. You have engines with Fadec ecu's.

I have had several planes with twin installations, currently I have the Horten with 2 MW44 engines using Fadec ECU's.

I use 1 channel. The Rx signal to the engines are Y leaded together, this allows both to start together. If you want to be able to stop one engine and reset the ecu and start it separately then I suggest you install 2 switches one in each of the red wire of the servo lead to the Y from the ECUs. This allows the second ecu to be either shut down when starting the first engine or if you are unhappy with the start of one engine you can switch the ecu off and reset it. To start an engine that has a reset ecu is simply a matter of smartly raising the throttle and dropping it. This will initiate the start in the second engine. The first one will not have responded significantly to the throttle increase if you are fairly quick. If things really get out of control just drop the trim and both engines stop.

In practice this is a simple routine and allows you to have direct control of both engines during the start.

Now with the Arado 555 I am currently working on I have 6 ecus Y leaded together with 6 switches to allow me to isolate one engine and start it separately.

Hope this helps.

John

kevinthoele

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Craig


I will be at Mississippi. Look forward to meeting you. I have Century F4 and Skymaster T38 at the event. If you see me please touch base. I will be on lookout for GA jets.

Jack Diaz

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Hi Kevin, I did it with the 12X.
You need three channels and two mixes.
You will need to mix throttle to say channel A, and throttle to channel B.
A three position switch (like aux 2 switch, if I recall correctly) will activate both mixes at the center position, and deactivate each of the mixes at the end positions.
The deactivated mix will keep the throttle at idle.
This is sort of a trial and error programming regarding the values for maintaining the deactivated throttle at idle.

Honestly, I really don't know if this is whorthwhile.

I have them in one channel and just keep my ECU's to receiver connectors handy (and identified: L or R). I simply disconnect and reconnect the engine that failed to start . The quick "full throttle" command to start the engine that failed will not bother the running engine at all.

Regards
Jack

kevinthoele

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Jack,

So you have Y on throttle to ECU and just unplug the side that didn't start. Great Idea.

Thanks,
Kevin

Jack Diaz

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Yes Kevin, that's it.

I also found that the most common cause for one engine failing to start in a twin engine airplane, is using a single propane tank for both engines.
The high propane demand causes the temperature in the propane tank to drop so much (due to the evaporation) that the propane freezes and stops flowing.
I use one tank per engine now. Almost 100% start success afterwards !

Jack

kevinthoele

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Thanks Jack. Will give that a try.