Hey guys,

I recently finished and flew my first scratch built twin EDF. It's a really big Concorde and flies pretty good. I had a question about thrust / throttle setting RPMs etc. Basically on straight and level flight I can't hear any difference in RPM's between about 80-100% throttle. Once my stick is at 80% anything further doesn't seem to effect the sound or speed of the jet. Here is a list of the parts I'm using.

Twin GWS 64mm EDF units with the stock black impellers.
Two 40 amp ESC from HobbyCity
Two Rhino 1250 11.1v 20C batteries

Any ideas? Is it really going faster or is it just my perception that it's not doing anything after 80% throttle.

Here is a link to a video of it flying.
http://www.youtube.com/watch?v=lQXlZfGaalE

"Mikey"
MikeysRC.com

<span style="font-size: larger;"><span style="font-family: Comic Sans MS;">Mike ... one way to know if you are getting more power is of course to use a watt meter, you can see the amp draw from 0%-100%. That is we assume that more amps means more thrust. But again if its about are you getting more 'thrust' you need to hook your plane up to some scales and run her up ... the scales will let you know how much thrust you are getting. It can be pulling or pushing against the scale.

I think you need better batts or actually bigger capacity if possible. The 64 mm EDFunits will pull about 20+A depending on the motor. Your batts are good for 25A max ... that means when pushed the their limit they will not hold the votage that well. If weight is as issue try at least 1,800 mAh 20C packs and you will see the difference in performance.
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tIANci, thanks for the help. Yeah I need to get a watt meter. I have been putting it off =). I'll try the scale idea for now. Yeah agreed Ineed bigger batteries. Those were pretty much the only matched pair I had. Well I did have (and try) a pair ot 2500mah 2OC batteries. Worked good but I thinik they were a bit heavy. I'll be placinf an order today for some 17-1800mah batts! Maybe a watt meter too!

Here is a better video of the Concorde in flight too. The first video hardly showed anything.


http://www.youtube.com/watch?v=nLEpLa-7aRA

"Mikey"
MikeysRC.com

Some pics.

I just saw this thread. What type of ESC do you use? I hope it's Turnigy because I know how to set up the throttle range on it and that it comes with detailed easy to read instructions. If so, it's very important to set the throttle range to have better authority over the throttle stick. I received mine and when tried it with Futaba 12FG the motor wasn't running before I move the throttle stick to 1/8 of the travel and was reaching max when the stick is just 1/2 the travel. If the ESC is not Turnigy, try to search the net for throttle range setting procedure and if you failed try the following (it might not work and might ruin your ESC/MOTOR, so do it at your own risk )

1. start your radio and make sure you are selecting the model correctly
2. move the throttle stick all the way up
3. connect your ESC
4. wait for couple of seconds and you'll hear the ESC beeps
5. move the throttle stick all the way down
6. you'll hear another confirmation (probably) long beep

Hope this helps. One more thing, if you are satisfied with your plane reaching maximum throttle with the stick only at 80% and don't know for sure how to set the throttle range, I advise you to keep it the way it is.

Azzam

Mikey ... the Concord looks great. I will try to scan something for you to use to measure thrust. Hope to do it tonight ...