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View Full Version : What BL and prop to replace slow stick brushed


chuckinnc
06-13-2012, 10:15 PM
I want to replace my stock brushed gearbox/prop with a non gearbox outrunner. I want to keep it light as possible and flying slow. I have seem
small bell type outrunners with stick mount built on from 1000 to 1800 kv, all are low current - around 10 amp. Would a 1000 - 1200kv still produce torque to swing a big prop & fly slow, or should I get a heavier 700 kv outrunner?

hayofstacks
06-13-2012, 11:44 PM
I have a 450 900kv and 450 1100kv.

If you do most of your flying low and slow, the lower kv is better.

What size prop and battery are you running now? I usually fly with a 10X5 or 10X4.7.

Sir Crash-A-Lot
06-14-2012, 02:03 AM
This is really not enough information to go on but here is what I would suggest for a 2 cell and 3 cell set up.

2 Cells I would use this motor:

http://www.bmkdesigns.net/emax-gt2215-9-1180kv-200-watt-brushless-motor.html

The Slow stick may be underpowered with a 2 cell set up for some peoples taste but I think that motor should be ok. If it seems underpowered to you I would use a 3 cell battery and drop the prop size to a 9x4.7 instead of the 10x4.7.

3 Cells I would use this motor. We have this one on a 3d foamy with a 10x4.7 prop and it flys very well.

http://www.bmkdesigns.net/emax-gt2215-12-905kv-200-watt-brushless-motor.html

Both will work with this esc:

http://www.bmkdesigns.net/emax-25-amp-brushless-speed-control.html

Mike

hayofstacks
06-14-2012, 04:21 AM
Another thing to think about, throwing a huge slow prop on a slow light airplane with make it torque badly. The stock brushed motor with gear box almost cancels out torque due to its counter-rotating design.

There are some brushless inrunners that will drop right in place of the stock 400 brushed motor and gear box, which might allow you good performance on a small 3 or even 2 cell battery. If you work it right, a smaller lighter motor with more power and less weight, depending on how heavy the esc is for the newer setup.

rcers
06-14-2012, 04:28 AM
Another thing to think about, throwing a huge slow prop on a slow light airplane with make it torque badly. The stock brushed motor with gear box almost cancels out torque due to its counter-rotating design.


Ummm what?

A single large spinning prop is what causes the "P" effect and torque. The tiny motor spinning the opposite direction does little to counter affect torque and nothing on "P" effect.

With the slow stick a lower kV motor work well. I used the Park 450 with a 10x6 GWS HD prop and loved it on my night flying slow stick.

Mike

hayofstacks
06-14-2012, 04:41 AM
I run a 900kv 450 sized motor on my slow stick too. With the 11" prop, gunning it quickly, it will lift a wheel off the ground and touch the wing tip. When I had the 1100kv motor with a 10X5 prop, it had very little torque roll, almost none at low throttle.

My dads stock 400 brushed slow stick with gear box, running the same sized 10X5 prop has virtually no torque roll at all. He is running a stock motor, stock gear box, stock esc, 800 mah 3 cell battery, stock gws servo's under the wing. We have even had an 11" prop on it.

rcers
06-14-2012, 02:53 PM
I run a 900kv 450 sized motor on my slow stick too. With the 11" prop, gunning it quickly, it will lift a wheel off the ground and touch the wing tip. When I had the 1100kv motor with a 10X5 prop, it had very little torque roll, almost none at low throttle.

My dads stock 400 brushed slow stick with gear box, running the same sized 10X5 prop has virtually no torque roll at all. He is running a stock motor, stock gear box, stock esc, 800 mah 3 cell battery, stock gws servo's under the wing. We have even had an 11" prop on it.

The cause is the power difference - not the gearbox. :)

Voltron
06-14-2012, 03:19 PM
I have this setup on my Stevens Aero Stik (Slow Stik with a balsa wing and tail surfaces). It works great.

http://www.headsuprc.com/servlet/the-1545/HURC-2410-dsh-09Y-Brushless-Motor/Detail

chuckinnc
06-14-2012, 04:36 PM
I looks like everything will be ok if the KV is around 1000, I plan on running 2s but may move up to 3s in a smaller ma pack. As a beginer I usually make short, slow flights and hope for no surprizes.

rcers
06-14-2012, 04:41 PM
You are right the slow stick will fly with MANY motors and setups - it is pretty non-critical.

You have to remember it is not a go fast airplane for sure. I like 3s on it as it gives you a good power margin for fun stuff and super windy day flying.

I use TP Lite 1320 3s packs on mine.

Beemerider
06-16-2012, 04:22 AM
I have the GWS brushless setup on mine. I'm not certain what the motor KV rating is. It flys very well on on a 2s 1200 mAh lipo and mine's a small red rocket on a 3s! I specifically bought the Stick to fly in the evenings here at a Jr High football field 3 minutes from the house.

I'm new to the Slo Stick and am still experimenting with props. Currently using a 10X4.7.

pizzano
06-16-2012, 08:43 AM
I use both the geared 400 brushed and the DST-1200 brushless outrunner.
Both fly great w/o issues....brushless has a little more top end speed.

Prop with brush motor & gear box = 10x5 & 10x6
Brushed ESC = 20amp
Battery = 7.4v 1200mah lipo

Prop with brushless outrunner = 9x6
Brushless ESC = 20amp
Battery = 11.1v 1200mah lipo

Specs on Brushless:
Kv (rpm/v)1200, Weight (g)57, Max Current (A)16, Resistance (mh)0, Max Voltage (V)11, Power(W)160, Shaft Width (mm)3, Can Length (mm)13, Total Length (mm)51

Rockin Robbins
06-21-2012, 06:46 PM
Mine has a Turnigy 2217-20 860kv turning an APC 11x4.5 SF prop. It's a monster with no bad torque effects habits. I run it at about 20 amps, motor is supposedly rated at 22A but I take it easy on the Chinese motors. But they're just about all Chinese motors nowdays.

The big prop gives me tremendous thrust at a low pitch speed. It accelerates straight up out of sight. You can hold it by the wingtip, point it at the sky, hit the throttle and be flying instantly, continuing straight up until you can't see it any more. Actually don't fly that high--bad stuff happens then.

I use a 40A Turnigy Super Brain data logging ESC but she's only pulling 18A wide open. You could get away with less. 1300mA Rhino battery gets me 20 minute flights with reserve to land safely.

mred
06-24-2012, 05:01 PM
I have an E-Max 2822 bell motor and it is fantastic. I can run a 2S or 3S battery and a 10X4.7 prop and there is plenty of power. I use a 1350MAh 3S battery and it has more then enough power to play around with. The motor cost me a whole $4.00 and I made my own motor mount for it. I made a few mods on the plane and am using ailerons on it. Flies fantastic, but you really need full aileron with rudder to turn it properly. I can fly around at half throttle and get a good 10 minuets of flight out of this setup.

Ed

flydiver
06-24-2012, 05:57 PM
2S vs 3S and prop sizes

Seems several people are advocating using EITHER/BOTH 2S and 3S on the same motor on their SS. Unless you are also changing props to suit the voltage change (33%...a LOT) this is a shortcut to burning out your motor and/or your ESC.

If you've been getting 'away with it', good for you, you're lucky. On the SS you tend to puddle around at very low throttle settings so that minimizes the impact on the motor (but not the ESC). On other setups with higher throttle settings it'll burn something up in no time.

I have a buddy that 'doesn't get it' with this issue. I've explained it numerous times. He flies the props he's got and if he breaks one he just throws in whatever is in the box. Then he wonders why his motors burn up.

Note on reply below - my buddy does have a wattmeter I talked him into. Can't figure out what to do with that either. Some folks just struggle with the electronic concepts.

Rockin Robbins
06-24-2012, 06:52 PM
<insert commercial for data logging ESC or watt meter here>

prefabu
06-24-2012, 11:40 PM
I'd try the HeadsUpRc suggestion above (the 2410-09Y). It's very cheap with the motor/ESC deal and $2 shipping. I have the same combo from a couple of years ago and it's still going strong. Like all cheap parts, quality control is marginal. Nothing serious, but you might have to resolder a bullet connector. The shafts on the the bell-style motors are sometimes *very* soft and tend to bend with any kind of impact, but they bend back just as easily. :)

You might also look at the Emax BL2220/10 on the same site (link (http://www.headsuprc.com/servlet/the-2071/Emax-BL2220-fdsh-10-Outrunner-Brushless/Detail)). It's just a bit heavier than a bell motor, but there are tons of prop options that would work well for a more performance-oriented Stick. Hmm, performance and Slow Stick? It's all relative!

mred
06-25-2012, 01:48 AM
Well now, I have a motor rated for 18 amps and a 25A ESC. My battery is a 1300 25C 3S and a 1320 15C 2S. I am drawing 18.5 amps with a 10X4.7 on 3S and 13 amps on same prop on 2S. Now would you like to tell me just what is going to burn up on this setup?? Except for take off when I use 100% throttle, I normally use about 60% and just cruse around. The last time I checked, none of these numbers gave me a concern about anything burning up................

Ed

flydiver
06-25-2012, 04:23 PM
For you, maybe nothing for the reason I stated, you are puddling around after take-off. You are also effectively propping down as you go to 2S.
Going the other direction, being propped properly for 2S and then putting on a 3S, (effectively over propping) is the issue folks often don't understand.
But....you do seem to be over propped (maybe-depending on your model), a pretty common problem.
Emax 2822 specs from HURC (http://www.headsuprc.com/servlet/the-1516/EMAX-CF2822-Outrunner-Brushless/Detail)

Motors at this level also are notorious for lack of quality assurance. Plus the Emax series is a confusing line (you do not offer us your motor specs). For example the specs may state it is a 1300kv motor but the reality can often be anything from 1200 > 1400 depending on how it was wound. I've heard of them coming with the wrong label with a completely different KV than specified [Emax 2822 conflicting specs] (http://www.wattflyer.com/forums/showthread.php?t=40363). That will make a prop difference. The low performance platform of the SS provides a lot of latitude so you get away with things you may not on another plane.
Rewind/Rebuild a Emax 2822 (http://www.rcgroups.com/forums/showthread.php?t=1462950)

I was trying to caution folks that didn't understand that dynamic.

Maybe you would care to explain it for them in greater detail, since I apparently am annoying?

mred
06-25-2012, 07:35 PM
Well, it would seem that Hobby King no longer carries this motor and the one you gave a reference to is not the one I have. Mine is a 1000KV motor marked for 9" and 10" props on 3S and can take 18 amps max. Using a 10X4.7 I pull 18.5A at full throttle and while I use full throttle at take off and climb, it may not last for more then 30 seconds and then I throttle back to somewhere around 10A to12A for cruse. I never put my Eagle Tree on it, so I am just guessing at that setting, but it is close I think. I can get you exact numbers if you like, as it is very easy to put the recorder on and fly it.

As for setting up my systems, I always use a watt meter and make sure that I am in the safe zone before even thinking of flying it. On most planes I use the recorder on the first few flights to get the best performance out of each plane, but on the SS I just let it go at the ground checks as I was not planning on flying it to the max and getting the best out of it. After all, it is a Slow Stick and they just sort of buzz around the sky at part throttle and I am not interested in getting the last little bit out of it like a pattern plane or 3D would.

I wasn't so much annoyed at what you said as I was disagreeing with your blanket statement. You need to be a little more specific in your statements. Just saying that you are over proped for 3S when coming from a 2S is not always correct.
"Seems several people are advocating using EITHER/BOTH 2S and 3S on the same motor on their SS. Unless you are also changing props to suit the voltage change (33%...a LOT) this is a shortcut to burning out your motor and/or your ESC. " There is nothing wrong with changing back and forth from a 2S to 3S if you are properly set up for 3S and just changing the battery and since my ESC is rated for 25A, I see no problem with that either. You assume I need to change props, but if it is already set up for 3S, then I don't need to change anything when using the two batteries. That sort of blanket statement is what I didn't care for. You assume I am set up for max current on 2S and changing to 3S will burn up my motor. You are correct IF I was set up for max current on 2S and I put a 3S battery on. However I am not and my motor always comes down cool to the touch. Even though I only paid $3.00 for the motor, I still try and take care of them and see no future in burning one up simply because they are cheap. I have 4 of these and they all are very happy on 3S pulling 18 amps. Never had one come down hot even flying at full throttle for the full flight. Normally though I just prop for about 16 or 17 amps if I plan to fly at full throttle all the time.

Ed