[Courtesy of Russ Tront, tront "at" cs.sfu.ca, September 1999 - originally posted on EFlight]
Well after two years of trying, I finally can get some serious duration out of my Eco heli. I was getting almost 1 minute per cell in forward flight and almost .8 minutes per cell hovering. I use either 8 or 10 2000mah cells. Though this is good (and embarasses some of the fixed wing pilots), it is still well short of what a few others have managed, and below what Ikarus advertises for a ferrite motor.
I have tried different motors; I have searched for friction everywhere; I have changed to fiberglass rotor blades as several people suggested that would add a minute to my flight time. Nothing helped much. I thought about changing throttles but was using the Jeti 30H that was recommended by Hobby Lobby and that surely many others were using. Finally, a staff member who worked at RC-Direct (doesn't work there anymore), recommended using a Schultz slim-35be throttle. He had actually compared the two. (I was dubious as Eco pilots on the net also said they had compared the wood to glass blades too, yet that didn't seem to make any difference. The set-up on a heli is so messy, and easy to mistake changes to. For instance, changing throttles requires changing the throttle travel and curves, and if you don't do it right you won't get optimum performance, so I was dubious to believe anything until I tried it carefully.)
Also recently, I have been coaching over the net a new Eco pilot named Martin in Australia. And he began to get much better duration than I. Since I was the one who was actually coaching him, this was frustrating to say the least. We discussed this and he said he was using a very good Steve Neu throttle and a very cheap Kyosho Magnetic Mayhem Reverse motor (the MMR is also one of my favorite motors). So tonight I finally got around to sticking in my new Schultz slim-35be throttle. I immediately got over 8 minutes of hover on 8 somewhat average 2000mah cells (i.e. 1 minute hover per cell vs. the previous .8 minutes hover per cell: a 25% increase!). I know that nothing else has changed. My transmitter was previously set perfectly for the old throttle, and I have carefully set the throttle travel and curves to suit the new throttle. I was so amazed with this duration increase I charged the battery again, and after dark using only the powerful back porch lights on my house, repeated the flight! Same 8.5 minutes hover on 8 2000mah cells. By the way, I too was using a MMR motor (mine has been modified to add ball bearings to it).
Now helis spend most of their time at 90% throttle setting so if a speed controller is not good in this range it would seriously impact a heli, but not so an airplane which often flys at either 100% throttle or say 70% throttle. I do not know if all Jeti 30H throttles are poor, or just mine. I now hope to get 1.2 minutes per cell in forward flight (which uses less power than hovering). So I am hoping that with a bigger 10 cell pack I will get 11-12 minutes of forward flight. I will be trying that this weekend when I can get to a field bigger than my small back yard. I will report to the eflight maillist after the weekend!
By the way, the BEC in the Schulz slim-35be throttle should not be used to power the 4 servos and gyro. I did it on 8 cells but it was a cool night and the heli wasn't high in case it quit. I would never do it on 9 or 10. To use a receiver pack, or as I do a special powerful home-made auxiliary BEC, disconnect the 'positive' wire that runs from the throttle to the receiver throttle jack. I just remove the tiny socket from the JR connector that plugs into my receiver throttle jack; not hard if you have ever assembled a JR connector and understand how they snap in. Then plug receiver power from where ever you get it into the receiver's battery jack.
Sorry to, in addition to the eflight maillist, also mail so many of my local RC friends and any Eco pilots I have email addresses for. But I'm just so ecstatic to have found the secret to increasing my Eco's duration!
Russ Tront Coquitlam, B.C., Canada
Subsequent posting by tront "at" cs.sfu.ca Sun, 05 Sep 1999 21:18:21 -0700 This message from tront "at" cs.sfu.ca brought to you by EFLIGHT!
Last week I wrote that I had gotten a significant improvement in my Eco 8 heli duration by changing from a Jeti 30H throttle to a Schultz slim-35be.
Unfortunately, I have not been able to duplicate the two flights of 8.5 minutes hovering on 8x2000 cells using a Kyosho Magnetic Mayhem Reverse motor. And it upsets me that I can't figure out why; I have thought about everything. Nonetheless, I am still getting a 1 minute improvement with the Schultz to 7.5 minutes.
I promised to report to the list how long a flight I can get with 2 more cells and with forward flight (which uses less current than hovering in my back yard). I am pleased to report that yesterday I got an 11 minute duration! This involved high altitude circuits only (no aerobatics) and no approaches to hover except at the end where I hovered nearby for the last minute to listen for when the battery was about to die. Needless to say this impressed the gas heli guys and an Kyosho EP Concept pilot present.
By the way, I notice that JR is coming out with a brand new electric heli design. They are advertising 5-6 minutes.
Russ Tront, Coquitlam, B.C., Canada.