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Old Oct 25, 2012, 01:20 AM
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New Zealand, Auckland
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Hmmn. Me & my friend never had issues with our completely stock Atom. We could loop , had no troubles gaining altitude & rudder didnt seem an issue.Perhaps they now use a stock weaker motor ?? Mine is no longer stock of course.
The stock batt isnt very good admitedly.

What we did do was separate & secure the pushrod tubes :cut the plasitic fig 8 thing & glue the tubes down securely at the front, with a bit of foam underneath. Stock, the servo pushrods & tubes bend at the front, maybe thats the cause of rudder issues??

Personaly, I run the 2900Kv motor. Possibly no faster than the 2000kv in the Atom ??
Id llike to see some pics of aileron conversions, thats 1 mod I have considered.
Ive just ordered one of these, hopefully a bit like a Atom with alerons,
http://www.hobbyking.com/hobbyking/s...dProduct=16023

I think we need more Atoms on youtube.
Heres 2 days ago, in wind , stock motor with bigger prop.Too windy for loops
HK Atom RC plane (0 min 57 sec)
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Old Oct 25, 2012, 11:04 AM
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United States, KS, Potwin
Joined Mar 2012
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Quote:
Originally Posted by 1101 View Post
Hmmn. Me & my friend never had issues with our completely stock Atom. We could loop , had no troubles gaining altitude & rudder didnt seem an issue.Perhaps they now use a stock weaker motor ?? Mine is no longer stock of course.
The stock batt isnt very good admitedly.

What we did do was separate & secure the pushrod tubes :cut the plasitic fig 8 thing & glue the tubes down securely at the front, with a bit of foam underneath. Stock, the servo pushrods & tubes bend at the front, maybe thats the cause of rudder issues??

Personaly, I run the 2900Kv motor. Possibly no faster than the 2000kv in the Atom ??
Id llike to see some pics of aileron conversions, thats 1 mod I have considered.
Ive just ordered one of these, hopefully a bit like a Atom with alerons,
http://www.hobbyking.com/hobbyking/s...dProduct=16023

I think we need more Atoms on youtube.
Heres 2 days ago, in wind , stock motor with bigger prop.Too windy for loops
http://youtu.be/15IZ6STAcpY
What size props and how do you mount them to the brushed motor?
Thanks
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Old Oct 25, 2012, 05:51 PM
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United States, WI, Muskego
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Killing time waiting for the brushless motors/props/ESC to arrive I figured I'd see how much room I'm able to save by switching over to the OrangeRx R410 receiver. Until now I've used the R610 6 channel receiver in the plastic case. I wasn't out of room, but why not save some space and weight if I can?

The pics show the size difference, which is considerable (in a small plane, at least). Even if you take the R610 out of the case it's still a bit larger.

On both receivers I secured the antenna with a dab of hot glue, but it was only the R410 that I was worried about as the antenna is smaller and feels kind of weak.

The new R410 was attached with Velcro back inside the open space behind the servos. Once the brushless ESC arrives I will try and fit that back there as well. I'm running a 500mAh battery and if I can push even a few grams farther back I should be better off.

Since I had the room I dropped in a battery monitor. I haven't flown with one of these yet, but I'll give it a shot with this plane to see if it keeps me honest on my flight time.
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Old Oct 25, 2012, 06:24 PM
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Originally Posted by 1101 View Post
Stock, the servo pushrods & tubes bend at the front, maybe thats the cause of rudder issues??
The bend in the servo pushrods and tubes is probably due to glue on the wire just before it enters the tube. The wire can't enter the tube so everything goes back. See if you can remove that glue from the wire. I did it the hard way by removing the wire.
http://www.rcgroups.com/forums/showp...4&postcount=46
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Old Oct 25, 2012, 09:19 PM
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I noticed some excess flex in the wire at the tail end, between the sleeve and the rudder. I've got an idea to fix this and take out some of the slop, I just need a few minutes to try it out.

Incidently, the slop is only when the pushrod is pushing. When it's pulling (right turn) it's fine.
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Old Oct 26, 2012, 07:42 PM
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New Zealand, Auckland
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Originally Posted by Joker 53150 View Post
Killing time waiting for the brushless motors/props/ESC to arrive I figured I'd see how much room I'm able to save by switching over to the OrangeRx R410 receiver.
Save even more room
Hot glue the receiver to the underside of the canopy. Free's up alot of room .
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Old Oct 26, 2012, 08:26 PM
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Originally Posted by Joker 53150 View Post
I noticed some excess flex in the wire at the tail end, between the sleeve and the rudder. I've got an idea to fix this and take out some of the slop, I just need a few minutes to try it out.

Incidently, the slop is only when the pushrod is pushing. When it's pulling (right turn) it's fine.
Look for glue on the wire between the servo and the tube. Probably just before it enters the tube. It only takes a very little bit to keep it from sliding into the tube.
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Old Oct 26, 2012, 09:34 PM
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Here's what I did to fix the slop I had in the rudder (see the pictures, they pretty much explain it all).

After testing I don't see any difference now between left and right rudder slop. Previously the pushrod flexed quite a bit when giving left rudder command. The way the plane is designed there is a long unsupported and thin pushrod which works, but not as well as it can.

The last picture is where I had issues with sticking pushrods, at the elevator where the pushrod exists the tube. It was binding on up elevator command, but down elevator was fine. I pulled the servo out along with the pushrod wire and cleaned the wire off. I also trimmed about 1/16" off the end of the pushrod tube since it was a little gummed up. After that the travel was fine.
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Old Oct 26, 2012, 10:47 PM
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Can someone please link me to what props and adapters I need for the stock motor? What have people been using?
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Old Oct 27, 2012, 04:25 PM
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It's too windy (again) to fly the Atom so I broke out the Super Cub and ran a couple batteries through it. It was too windy to have much fun so I came home to find a new box of toys from Hong Kong arrived. On a Saturday! With my wife gone all day! I assume this is Karma catching up with me finally.

So as I've said before, I find the Atom woefully underpowered for any real excitement and I'm upgrading to brushless goodness. Today's delivery included two motors and four prop choices. The motors are the Turnigy 1800 2000kv and the C10 Micro 2900kv. Props include 5x3, 4x2.5, 4.5x4, and 4x4. I went with these choices to try and get a good feel for what each change in length and pitch would really give me. Plus they were in stock and cheap...

I tried each prop with both motors (and I have another motor - the C1822 2100kv - due to arrive in a few days as well) and checked the watts, amps, and grams of thrust to compare against the stock brushed motor. I'm not looking for unlimited vertical to the sun, just a respectable increase in the "fun factor".

Measuring the watts and amps is easily done with the watt meter in the picture. To measure thrust I got a little creative as shown in that same picture. To be honest I'm not sure if it's an accurate way to do it, so feel free to provide constructive comments. The way I see it, if the scale is zero'd out between runs and the only variable that changes is the prop I should be somewhat close to an accurate measurement. The wood the motor is mounted to is only touching the scale on the right and a spacer on the far left end.

To start I put the Atom nose straight down on the scale and zero'd it out with the motor off. I ran it up to full speed pointing directly down at the scale three times and averaged:
106 grams of thrust on the scale, 3.6A and 26 watts, stock prop.

Next up was the Turnigy 1811 2000kv motor.
84 grams of thrust on the scale, 2.5A and 19 watts, 4x4 prop.
91 grams of thrust on the scale, 1.8A and 14 watts, 4x2.5 prop.
115 grams of thrust on the scale, 2.6A and 21 watts, 4.5x4 prop.
128 grams of thrust on the scale, 2.4A and 19 watts, 5x3 prop.

The 4x4 and the 4x2.5 are immediately out of the running as they both provide less push than the stock prop/motor combination.

Changing over to the C10 motor:
128 grams of thrust on the scale, 4.3A and 31 watts, 4.5x4 prop.
164 grams of thrust on the scale, 4A and 28 watts, 5x3 prop.
(I didn't test the 4x4 or 4x2.5 props with the C10.)

So the big power winner is the C10 with the 5x3. HOWEVER, that 5" prop won't clear the tail boom unless I mount the motor higher than the stock location while the 4.5x4 will clear it (barely). With that in mind, I'm not sure which way I'm leaning. Regarding the motor height I don't know if pushing it up 1/4" or so would really change the flight characteristics or not (probably not much, if at all). Either way, I'll use the C10 for the Atom.

All tests were done using a Turnigy 500mAh 2 cell 20-30C battery. The C10 is rated to handle up to a 3 cell battery which could really make it rock! The C1822 which I've got coming was purchased with a different plane in mind, but I'll probably test it with all these props as well just to see what it can do.

What are the thoughts on how the tests were done, what changing the motor height will do, props used, etc?
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Old Oct 27, 2012, 04:35 PM
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Originally Posted by WhiteGoldSlugga View Post
Can someone please link me to what props and adapters I need for the stock motor? What have people been using?
You could use a few of the props I listed above, but you'll need a prop adapter. The closest size I had was for a 2mm prop shaft, but that was just slightly too small to fit on the stock motor's prop shaft. I think the next size up is 2.3mm http://www.hobbyking.com/hobbyking/s...0pcs_bag_.html. 3mm is way too big. Prop length would be 4" maximum, but slightly shorter would be safer so you don't accidently slice your boom. For the stock motor you may need to try a few different options for the pitch.
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Old Oct 28, 2012, 05:08 PM
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Thanks for the numbers Joker, it does seem to be that the 5x3 route is the way to go. I plugged the numbers into http://adamone.rchomepage.com/calc_motor.htm and got similar (if a bit larger results).

Finding this thread has inspired me to dust off my battered Atom. I've extended the rudder full length and added ailerons with 2 3.7g servos (might play with flaperons later!).

The C10 looks interesting but I'm waiting for HK to get the Turnigy 1811 2900kv back in stock. I like that it comes with a prop adaptor and takes 5.8A

Mark
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Old Oct 28, 2012, 06:57 PM
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Cool program, I hadn't seen that before, thanks!

I weighed the options and decided to go with a setup that would allow me to run the 5" prop if wanted. Instead of doing what others have done and create a new taller firewall for the motor I raised the entire pod 3/8" with a wood spacer. Prop clearace to the boom is about 1/8" and I gave the boom two layers of packing tape to protect it in case of accidental strike by the prop. Additionally, a 3/16" carbon fiber tube was epoxied from the bottom of the wing, through the wood spacer, and into the pod for a little extra strength. If I had any quality foam laying around I'd have used that instead of the wood, but then I'd have gone with two carbon fiber tubes to be safe since I'm not sure how much extra torque I'm getting now.

One thing I really don't like about this motor is that you can't easily remove it from the mounting plate. It's nowhere near as easy to remove as the generic "X" style mounting plate. Hopefully I never have to remove this one, as it will result in a fair amount of damage and re-building.

Winds today were calmer than yesterday so I decided to give the updated Atom a test-flight with the 5" prop. Upon launch it was a little less "smooth" compared to the stock setup. Possibly due to the extra height of the pod, maybe a different thrust angle, could be the extra thrust of the motor, torque of the bigger prop, etc. But it wasn't bad and I got two good flights out of the 500mAh battery before throwing the Super Cub into the air. Checking the battery after I got home showed I could have easily gotten another 3-4 minutes of flight out of that battery.

The flight of the Atom was vastly improved over stock once the launch was done and the plane was cruising and trimmed out. The climb rate was much better and I never got the feeling it was going to stall on me like I did with the stock motor. I forgot to bring the other prop along to try. When my son flies the Atom he'll use the 4.5x4 until he's comfortable with it, and then he can try the 5x3.

I was using a Spektrum 4 channel radio (that came with my Super Cub) and tried high and low rates. High rate was nice once everything was underway, and when it was time to land I switched over to low rates to avoid dipping a wing due to too much input.

As mentioned, I tossed the Super Cub in the air after running a battery through the Atom. Before doing so I put in a battery alarm which I just received with a recent delivery from Hong Kong. I hadn't used one before and wanted to see how well it worked. I was flying for much longer than I ever dared on a 1500mAh Zippy. Multiple landings and approaches before finally hearing the beeps telling me at least one cell was getting low. Giddy with excitement I did something supid and flew the plane directly between me and the setting sun. The wind was blowing a bit and I completely lost orientation on the plane. It started getting farther and farther away, but at least there were no trees near it. Instead there was a corn field, which is better than a tree any day of the week. Until you need to search for your missing plane 100 yards into the field...

The ground was dry-ish, the corn wasn't too tall, and I was able to make the alarm beep by running all servos at the same time which guided me to the plane in quick order. Without the alarm I'd have eventually found the plane, but it certainly would have taken a LOT longer!

I seem to recall another type of alarm that goes off only when the RX loses signal from the TX. That would have been useful as well, and I might look into that for my next order. When the plane is missing just turn off the transmitter and listen for the alarm.

I haven't weighed the Atom now to compare against it's advertised stock weight, but I'm sure it is slightly heavier (bigger battery and wood spacer to increase weight, lighter motor, ESC, and RX to off-set it somewhat). After moving the ESC and micro RX directly under the wing I now have plenty of room to use a battery alarm - or to at least try it. The extra power I now have should handle the extra few grams of insurance.

When time/winds permit I'm going to try the 4.5x4 prop out. If it's still a good improvement over stock I'll probably NOT raise the pod for the Atom I ordered for my dad. Stock height, better prop, no extra weight, lots less work for me, etc. It'll be his first RC plane so he doesn't need tons of extra power - just enough to let him learn.

Back to the longer flight on the Super Cub... I've never flown it that long before without swapping the battery. After recovery and bringing it home I put the tester on the battery and found one cell about .15v lower than the other two. Not sure why this is, but I'll keep an eye on it as it cycles the next few flights.
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Old Oct 28, 2012, 07:56 PM
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Oh, and the current flying weight is 157 grams with the 500mAh battery. HK shows the stock flying weight as 145 grams. I could probably have saved a few grams with foam instead of wood for the spacer, but I can live with the 12 extra grams. The stock battery drops it back down to 147 grams, so evidently that stock motor and ESC were pretty heavy!
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Old Oct 28, 2012, 10:45 PM
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Somebody educate me a bit on motors, please, I'm trying to make sense of something.

Earlier I posted that the Turnigy 1811 2000kv motor read 2.4A and 19 watts when using a 5x3 prop. Looking at the stats for the motor on the HK website (which I know is probably hit or miss to begin with) it shows a max current for that motor of 4.1A.

Since I'm still well under their stated max rating, does that mean I could still go with a more aggressive prop which would draw more power, as long as I stay below 4.1A?

Same question for the C10 motor, although the HK website calls out the max current at 5A and I was running 4.3A on the 4.5x4 and 4A on the 5x3 so I may not have that much room to increase the pitch.

I like the mounting base of the 1811 more than the C10, so maybe a 4.5" prop with a more aggressive pitch would be the ticket - if I can get to around 130-140 grams of thrust without having to hack the motor pod I should be pretty happy. Not hacking the pod should mean a slightly lower weight as well.

Hmmm, now I'm confused and really looking forward to building the Atom for my dad!
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