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E-Starter prop and power question

Old 12-12-2005, 02:41 PM
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pox67
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Default E-Starter prop and power question

Hi all,

been going through the site getting tips for building an E-Starter. This will be my first plane since having 2 channel gliders as a kid.

Here is what I picked up at the hobby store:
- E-Starter (EM350 motor)
- Apogee 3S1P 830mah battery (plan on getting a higher rated battery when I can afford it)
- charger for 3 cell Li-Po
- ECS - Castle Creations Sprite-25 ( they are exchanging this for another ECS as they didn't know it doesn't have a cutoff for Li-Pos)
- Waiting for a Spektrum 6 channel radio to come in.

So after reading a lot of threads and getting a lot of build tips I am worried that the battery I have will be too strong for the 350 motor.

If I just run the motor at 1/2 speed will that be OK?
Or can I set the end point on the throttle through the radio to be 2/3? (That would be like a 2S 8.4v pack?)

If I can use the 3S 11.1v battery which prop should I use?
2 came with the kit, a 9070 and a 8060, if neither of these would be any good what can you suggest?

Thanks for any input!
Old 12-13-2005, 07:31 AM
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AJ1202
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Default RE: E-Starter prop and power question

Pox, I have a new E-Starter and I would say a 2s lipo would be OK, 3s would be too much, just make sure your ESC is lipo compatible and you have a cut out to prevent too low voltage drop on batt. I wouldn't think you will have to worry about going through all the settings if you went with 2s lipo, it's like using 7.4 V. I.m using 8.4 nimh and it's fine. I would NOT go to 11.1 V or you'll cook the motor. If your right there why not go ahead and go brushless, you can get a good motor for another $ 30.00 from Balsapr then you would be set. Either of the props that come with should be good, I flew mine with the smaller one and it can pull tight loops from level flight, I'm gonna try the larger prop next. I'm also most likely going to go brushless on mine
Your going to like this plane, it fly's great, very stable and forgiving.
Pox why don't you come on over to the backyard/parkflyers and join us on the Shun Da Cub thread
Good luck
Old 12-13-2005, 12:10 PM
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Default RE: E-Starter prop and power question

Thanks AJ1202,

problem is the battery is bought and the charger. I will have to find a way to keep the throttle reduced or set the rate with the transmitter. The website for the Spektrum 6 channel doesn't say anything about changing throttle rates though.
Old 12-13-2005, 01:19 PM
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Default RE: E-Starter prop and power question

OK I understand, I will get you an answer how to make it work but realy come on over to Shun Da thread, bunch of good guy's, some running brushless, some running lipo's, all kinds of planes, not just Cubs
See ya there and I'll get you an answer
Old 12-13-2005, 06:37 PM
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Default RE: E-Starter prop and power question

OK here's the skinny, if your carefull with the throttle and stay wit the smaller prop, maybe even smaller than the 2 you have it will work, it breaks down like this hte motor will turn so many revs for every volt you put to it, so higher voltage faster revs, brushed motors only run at about 65% efeciancy so the other 35% is lost in heat, so if you run faster revs you will generate more heat, hence frying the motor. There is a whole formula for amps and volts to determine what will work and what won't. I never asked, is this your first plane, if so good choice. I have to say with the other components your getting I would spring another 30 bucks and get a brushless motor and eleminate this potencial nightmare of figuring out how to control your voltage to not cook the brushed motor. A freind of mine fried a 400 direct drive with a 3s lipo and it is designed for higher rpm than the geared 350. One last thing, if you stay with the brushed motor you need to do a water breakin to it before you hook up the normal battery. If you need to know how just ask
Old 12-13-2005, 08:24 PM
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Default RE: E-Starter prop and power question

Thanks AJ1202, that is all the info I was looking for

I'll grab a smaller few smaller props next time I am up at the store.
I figure if I keep the throttle under 2/3s that will be equivalent to a 2s battery. If the Spektrum DX6 doesn't have a throttle rate change I'll just tape off the top portion of the range on the TX.

I'll go brushless when I burn out this motor. I don't want to go the custom route yet as this is my first plane so want the stock setup as much as possible to eliminate building errors.

The CC Sprite-25 ESC is going back to the store and I'll pick up the cheapest Li-Po compatible ESC they that can take about 10A.

I haven't heard anything about this "water break in", I think you better explain before I douse the motor in the sink!

Thanks for the info.
Old 12-13-2005, 09:55 PM
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Default RE: E-Starter prop and power question

OK don't do that
Also I found out if and or when you go brushless you have to change ESC again to be compatible with motor, brushed 2 wires, brushless 3 wires
OK for water break in, it's very simple but also important, explanation, when a motor is new the brushes are flat and the armiture is round, when the motor runs it generates sparks, it takes a while to wear the brushes down dry and that puts a lot od carbon in the motor armature.
OK get some distilled water(this is important) tap water contains iron and other bad things, then using a D cell batt hook up your wires using electric tape or duct tape, making sure the motor is turing in the right direction, in this case the red dot on the motor will indicate poss. hook the motor up and start it running then ease it into the glass of distilled water and let it run, now some say let it run untill the batt dies but I don't agree because I used a energizer and found it ran all night and was still running the next morning []. so now I time it for 1 hour, seems to do the trick. This method of break in allows the brushes to wear into a pattern gently so when you fire it up for the first time in the pane you are getting almost complete efficiancy from it.
be sure to dry it out good and put a drop of oil on the bushings at front and back
couple building tips, if your interested, set the ailerons for small amount of throw, this thing turns great with minimum amount. use sub micro servo's if you can, I used standard micro's but will most likely change them. the directions are not accurate about the front mount for the wing, or it just reads wrong or something, you want the plastic peice with the holes on the fuse and the pins on the wing, you'll see what I mean, it leads you to think the barbed part should bee ont the fuse to spur the wing to hold it on. I took one of the extra pushrod tubes and ran it on the opposite side of the fuse from the elevator tube and ran my antenna wire through it, keeps it out of the way and secure inside the fuse. Theres more but I don't know how far along you are so I'll stop here
Old 12-13-2005, 09:58 PM
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Default RE: E-Starter prop and power question

Oh yeah here's a pic of mine when I was finnished
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Old 12-14-2005, 08:55 AM
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pox67
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Default RE: E-Starter prop and power question

Thanks for the water break in info, if I can get the motor out of the front of the plane I will do that. Problem is it is already glued in!

Servos: I think the Spektrum DX6 comes with sub micro servos. They are S75 servos, 7.5grams
The wing attachment took me a while to work out and after reading a few posts I decided to go with the bamboo and rubber band setup. It seems screwing the wing down can rip out a lot of foam on a bad landing/crash.

I am almost finished, just got to add the landing gear and the radio equipment when I get it.

I did some strengthening by adding clear packing tape top and bottom of the wing and the fuselage. After reading the tail wheel can rip out the tail/rudder when landing I decided to go with a balsa tail skid instead until I am comfortable with landing. I strengthened the ailerons with tape as well as they seemed kind of flimsy, the elevator got a bot of tape as well.

Nice looking plane you made, mine won't look so good as I'll just put on some of the included decals...I fully expect it to look like frankenplane after a few flights

Thanks for the tips AJ1202.
Old 12-14-2005, 09:51 AM
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Default RE: E-Starter prop and power question

Idea on water break-in and one more caution on Shun Da thread
Old 12-17-2005, 04:24 PM
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Default RE: E-Starter prop and power question

AJ1202, In have uploaded a couple of photos of how I strengthened the landing gear and the tail skid I put on.

For the LG I just epoxied a spare piece of foam across it as I epoxied the base in.

For the tail skid I used some of the left over foam from the wing strut stuff and used the GWS glue to stick 2 pieces together then shaped it. I used the GWS glue to stick a strip of margarine container to the out side of the skid to make it slip better and strengthen it. Then epoxies the skid to the tail after sanding bothareas nice and flat. Seem pretty strong but the proof will come when it flies.

Took your suggestion and changed over to brushless. I exchanged the CC Sprite-25 ESC for a CC Thunderbird-18. Picked up a Hacker E3-49 which is a 4900kv inrunner...the guy in the store said it should make the E-Starter go vertical so I'll have to be easy on the throttle

Still waiting on the Spektrum radio system to come in so it will be a few weeks before maiden

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Old 12-17-2005, 09:31 PM
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Default RE: E-Starter prop and power question

Hi Pox, looks good. I like the tail skid, I might have to do something like that as mine has already come loose and wobbles with just a few landings on it, The only prob I see with the LG is I have to remove mine for traveling, I keep them in a container with the gear and wings off
I think I'm going to make a snap in lock like on my cub. Hey what are you doing back over hear
your part of the gang now, so go back.
Old 12-18-2005, 01:42 AM
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Default RE: E-Starter prop and power question

I see you've installed the stock battery hatch. Have you secured it in any way? Unless GWS has changed the design, there is a good chance you'll see your batteries leave the plane when the plane encounters some G's.

Never happened to me, but I've read about it and know it happened to a fellow I see at the field.

Not a pretty sight. [X(]
Old 12-18-2005, 02:40 AM
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Default RE: E-Starter prop and power question

ORIGINAL: Time Pilot
I see you've installed the stock battery hatch. Have you secured it in any way? Unless GWS has changed the design, there is a good chance you'll see your batteries leave the plane when the plane encounters some G's.
Uh yeah... I can vouch for that. I had my brand new 2100 3S lipo "exit" the plane on a hard bank. 200' drop does not do a lipo good (poof). Nor for the plane. It did a nose dive straight into the terf, and broke into 5 or 6 pieces. The lipo was done for. But I glued the E-Starter back together, and she still flies to this day! Her nickname is now Frankenplane though. And sponsored by Gorilla Glue!
Old 12-18-2005, 11:54 AM
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Default RE: E-Starter prop and power question

It is coming along nicely, can't wait for the radio to come in!

I was thinking about the battery plate as I had read a few posts about it coming out. Then when glueing it in I noticed that epoxy doesn't stick to the hatch plate plastic! Man that is just dumb...the epoxy peels right off it. I tested using a couple of the rubber bands going from the wing support struts on the fuselage, you can see what I mean from the pic. Seems to hold it in quite tightly, especially if I double over the rubber band. The supports are over epoxied in so shouldn't come lose either.

AJ1202, super long threads like the Shun Da Cub one drive me nuts as I can never find the info I want in them
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Old 12-18-2005, 01:56 PM
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Default RE: E-Starter prop and power question

pox67: That's similar to what I ended up with. Although I didn't think to use the wing strut supports to anchor the rubber bands. As long as those stay put, that was a good idea. What I did was to take a couple pieces of carbon rod about 1/2" long, and stab them into the fuse on either sides of the battery area, glued in with epoxy. Then I used those as anchors for my rubber bands. I ran two sets just to be sure, one in the front, one in the back.

Here's a pic when I had three carbon tubes. As mentioned before, I've since changed to four (two sets). You can also see my custom battery door, that was necessary for my 2000mah 3S lipo to fit. It failed by the way! lol Hence the need for the rubber bands. I think, as you mentioned, I had a problem with the epoxy not sticking to the plastic hinge lock (which I re-used) and it opened during flight.

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Old 12-18-2005, 03:36 PM
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Default RE: E-Starter prop and power question

twinturbostang, I might go that way with the battery door if my setup feels to weak. I could pull out the plastic door that is in their now and all the epoxy around it and save a few ounces! Then just make a flat battery cover which is held in by the rubber bands.

I am putting the Hacker E3-49 in the plane now. It seems I have one of the B gear boxes which is 1:4.43, Horizon Hobby is recommending a 6.61 gear box. Does any one know if the 4.43 gear box will be OK and what size prop would be best?
Old 12-19-2005, 02:00 AM
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Default RE: E-Starter prop and power question

I left the hatch off completely and have my batteries held in by a series of 4 rubber bands. It doesn't look very pretty, but it sure makes changing batteries a snap and offers a bit of give on a hard landing.

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