RE: E-Starter woes. Short flight time, battery barbecue, etc.

RE: E-Starter woes. Short flight time, battery barbecue, etc.
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RE: E-Starter woes. Short flight time, battery barb... - 9/21/2005 5:02:02 PM

twinturbostang

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Joined: 8/29/2005
From: Germantown, MD, USA
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Checking some other resources to see if I can get a 3 mm shaft. If I can find one, I might be able to press it in myself. I actually found a drill bit that might have worked (it was the same diameter), but not long enough. I wonder if I can find one long enough, then cut it to the right length before the flutes. And a drill bit is made from tool steel and made to spin at high rpm. Should work great! Hmm...

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RE: E-Starter woes. Short flight time, battery barb... - 9/21/2005 5:05:39 PM

TManiaci

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'stang,

Isn't there a snap-ring on the prop-end of that shaft?

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RE: E-Starter woes. Short flight time, battery barb... - 9/21/2005 8:25:14 PM

twinturbostang

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Nope. The shaft is pressed into the can, and then the can/shaft is inserted into the stator from the back of the motor. Forward pull from the prop holds it all together.

I'm all set though. I called McMaster and they have 3mm shafts that are 2 3/4" long. I can press the old one out, cut the new one to length (40mm), and then presses it in and I'm golden. I ordered 3 (@ $2.22 each)... just in case.

AND it should be here tomorrow!

I've already pressed out the broken shaft. Just waiting on the new one. Here's a pic...

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< Message edited by twinturbostang -- 9/21/2005 8:26:19 PM >

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RE: E-Starter woes. Short flight time, battery barb... - 9/21/2005 8:28:07 PM

TManiaci

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'stang,

That shaft looks like it has a step-down diameter where it broke. Are you sure it's all the same diameter full length?

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RE: E-Starter woes. Short flight time, battery bar... - 9/21/2005 9:01:02 PM

twinturbostang

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Yes it does have a step down. Good eye. 3mm down to 2.3mm. I'm just going to do a 3mm shaft, and then drill out my prop adapter to 3mm so it will still work. Should be stronger too that way. The step down is exactly where it broke, so that's a weak point.

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RE: E-Starter woes. Short flight time, battery bar... - 9/23/2005 7:28:42 PM

twinturbostang

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From: Germantown, MD, USA
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Humpty Dumpty lives again!!

I decided ...what the hell... and glued the E-Starter back together again. Sure doesn't look pretty now! But it flew. Was downright scary though. I had a bit of wind today, and there were some very strange wind gusts and swirls. I definitely need to find another field to fly at, because this one is becoming VERY unpredictable. Flew it for about 7-8 minutes, with a couple of landings inbetween for trim adjustments and stuff. And I'd had enough at that point. Was not a relaxing flight at all. I've got several issues remaing....

Tail dragging: I put the CG right where GWS recommends this time, and it's awful in turns. Feels like there's a lead weight attached to the tail. Would moving the cg forward help this condition? It seems rather severe.

Power: WAY TOO MUCH POWER FOR ME RIGHT NOW!!! Good grief! I barely made it to half throttle and that was ENOUGH for me! LOL Do you think I could play with the ATV (Adjustable Travel Volume) for throttle channel to make it a little easier on me? I'm trying to get more stick motion so I'm not concentrated at the bottom. I wasn't sure if you can do that on the throttle channel with an ESC.

Oh, I've got the battery in there good now. After gluing it all back together, the battery door fit a lot more snug with the latch mechanism. BUT, I also added an extra measure of safety just to make sure it doesn't go anywhere (see pic below). Rubber bands securely held in place by three pieces of carbon rod stabbed into the fuse and epoxied in place.

I also got my motor back together. I pressed the broken shaft out of the can. Ordered a new 3mm tool steel shaft from McMaster wed. and it arrived yesterday! Pressed the new shaft in with my drill press (using the chuck to hold the shaft perfectly square with the can). And then cut the shaft down to the length I needed with my Dremel w/ a cutoff wheel. See pics below of the shaft installed (before cut to length).

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< Message edited by twinturbostang -- 9/23/2005 7:31:08 PM >

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RE: E-Starter woes. Short flight time, battery bar... - 9/23/2005 9:01:41 PM

TManiaci

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'stang,

Nice job!

Tail dragging.... forward CG will help, but some planes just do that. Forward CG will always make a plane more stable, so don't be afraid to experiment. Our Nexstar 46 Trainer (e-conversion) does it real bad, hate it. Gotta put in backwards rudder to make it turn properly. Thinking I will try a Aileron-Rudder mix to automatically compensate. Left turn should require right rudder to keep the nose up, and carry altitude. Our trouble is the opposite, tail drops and nose goes up in the turn. Left turn requires left rudder to carry the tail thru the turn.

Best way to widen power band without compromising is to downsize the prop. Most ESC's auto-detect throttle for full throw, so I don't think you can limit the span with programming (never tried). Less prop equals more throttle throw, longer flight times, less loading the motor and esc... all good.

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RE: E-Starter woes. Short flight time, battery bar... - 9/23/2005 10:26:42 PM

twinturbostang

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From: Germantown, MD, USA
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quote:

ORIGINAL: TManiaci

'stang,

Nice job!

Thanks!

Worked out really well. Got back up in the air sooner and for less money than if I had shipped it out to California (I'm on the East Coast here).

quote:

Tail dragging.... forward CG will help, but some planes just do that. Forward CG will always make a plane more stable, so don't be afraid to experiment. Our Nexstar 46 Trainer (e-conversion) does it real bad, hate it. Gotta put in backwards rudder to make it turn properly. Thinking I will try a Aileron-Rudder mix to automatically compensate. Left turn should require right rudder to keep the nose up, and carry altitude. Our trouble is the opposite, tail drops and nose goes up in the turn. Left turn requires left rudder to carry the tail thru the turn.

That's EXACTLY what my plane is doing. And it's VERY aggravating! I can move the battery forward some. I will try that and see if it improves. It seems GWS did not label the CG in the right spot though.

quote:

Best way to widen power band without compromising is to downsize the prop. Most ESC's auto-detect throttle for full throw, so I don't think you can limit the span with programming (never tried). Less prop equals more throttle throw, longer flight times, less loading the motor and esc... all good.

Ok, I could do that. That won't over-rev the motor will it? Oh, I tried it with adjusted travel in the Tx. Didn't seem to help. I couldn't really tell if it was doing anything or not. I held it at WOT, and adjusted the % on the Tx, and I couldn't really hear a difference in pitch of the motor. Maybe just slightly, but definitely not enough.

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RE: E-Starter woes. Short flight time, battery bar... - 9/23/2005 10:37:52 PM

TManiaci

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Don't worry about over-revving. The battery voltage limits the rpm, and the motors can run safely without a prop at all without damage because there is no "load" on it.

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RE: E-Starter woes. Short flight time, battery bar... - 9/24/2005 3:30:03 AM

twinturbostang

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Now THAT WAS FUN!!! Took it back up after work, and had a blast! Things that changed...

Less wind this time.
CG move forward by relocating the battery.

Man, what a difference changing the CG made! Probably moved it forward 1/4" to 3/8" or so. Plane behaves totally different now. Turns are much improved. No more tail dragging, or very little at the worst. A lot more stable too. Part of that could have been from less wind. But I have a feeling a large part of it was from the CG move. I finally got to open 'er up this time! Spent a considerable amount of time at 1/2 to full throttle. Did loops, rolls, Split S's, Stall turns, etc. Now keep in mind, my maneuvers would probably make an IMAC judge throw up. haha But I'm having a lot of fun though.

What was really fun was coming down the line, pulling vertical right in front of me, and just hanging on until I chopped the throttle. Cool!

It would go vertical for as long as I pointed it at the sky. Hmm... this doesn't sound too much like an E-Starter anymore! haha

So with all that, I got about 12-13 minute flight time. I guess I was hoping for longer than that. But geez, twice the flight time and twice the power as the stock setup. Not too shabby I guess. I'm assuming that translates into a discharge rate of about 5C right? Oh, and the pack definitely got warm, but not scalding hot like the Ni-MH pack used to do. How warm can the lipo packs be allowed to get before you have problems?

I'm getting better at throttle management too. So I might just leave the 7x4 prop on there.

< Message edited by twinturbostang -- 9/24/2005 3:33:01 AM >

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RE: E-Starter woes. Short flight time, battery bar... - 9/24/2005 5:22:47 AM

TManiaci

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Move that CG further forward, until the turns become self-coordinated. You'll love it there, and it will probably fly inverted neutral too. Also should make rolls better as well.

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RE: E-Starter woes. Short flight time, battery bar... - 9/24/2005 5:26:44 AM

twinturbostang

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Battery is as far forward as I can get it. Unless I do some more hacking on the foam. lol

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RE: E-Starter woes. Short flight time, battery bar... - 9/25/2005 4:49:00 AM

twinturbostang

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Sweet. Got a 15 minute flight in today. Flew at a park down the street from my house. Little bit smaller than the fi