Author Topic: 1/2a size Electric System (Read 1923 times)

Ken Culbertson · « **on:** April 23, 2023, 09:24:22 AM »

Could someone direct me to the proper setup for a 1/2a electric. Motor, ESC, Battery, Timer. I have been exclusively in the .46 to .75 sizes since going electrics and I don't know squat about the smaller stuff. Cheap is OK for this project.

Ken

944_Jim · « **Reply #1 on:** April 23, 2023, 12:18:27 PM »

Mr. Ken,

I have no experience with electric either. I found two good references. RSM and Stevens offer packages. By reviewing the smaller Stevens wares, you can get an idea of appropriate parts/pieces and what size airframe they are specified to support.

https://www.stevensaero.com/
~~https://www.rsmdistribution.com/categorymenu.php?cat=28~~ bad link

Good luck...and please share what you find and what you think with respect to the little guys.

944_Jim · « **Reply #2 on:** April 23, 2023, 12:59:34 PM »

I just double-checked the RSM link. It doesn't break down into their electric stuff like it did a few years ago. You may need to pull down their PDF catalog, or contact them directly.

Steve Berry · « **Reply #3 on:** April 23, 2023, 02:00:46 PM »

On the RSM site:

Glow Equivalent .061 (1CC)

RSM 061 Competition Level System equal to .061 Glow Power. Includes RSM Black Tiger BK2836C Motor, 20 Amp Speed Controller, KR Flight Manager, 1300 mAh 3 cell Battery & 7x5 Pusher Prop. Comes with all programming installed. This power system is ready to be installed in your model. Just flip the switch and fly!

Part Number: RSM061SYSC
RSM Price $139.99

In stock, ready to go.

They do have the sport system version, but it out of stock / unavailable right now.

It's probably a good match to something along the lines of the Brodak Baby Pathfinder or similar sized plane.

For a smaller plane, such as most 1/2As that are out there, you would need to piecemeal it together, I'm afraid. I've been trying to figure that out as well.

Equivalents of a Baby Bee or Golden Bee or Black Widow....that would be helpful. Another aspect that could work are those little 18650 or 21700 batteries in a 2- or 3-cell holder. Wouldn't have to worry about a battery pack. Just mount the battery holder on the CG under the wing and you should be good to go. Use one of the little DIY timers and then you just need a small motor and appropriate ESC.

For nostalgia, go here: https://willynillies.com/buy-here/ols/categories/cox-motor-mounts

Steve

Paul Smith · « **Reply #4 on:** April 23, 2023, 04:06:55 PM »

A Cox 1/2A engine, the Black Widow weighs 2.4 ounces and will drive its propellor at 17,000 RPM.
A FORA .049 weighs 3.1 ounces and will drive its propellor at 29,000 RPM.
.

Tim Wescott · « **Reply #5 on:** April 23, 2023, 04:07:59 PM »

I think a 800-900mAh 3-cell pack should be a better match for the little Cox reedies. Build out from there with a motor that has a Kv rating of 1500-2200 and a 6" prop.

If you're not flying stunt -- and especially for a trainer -- using an 2.4GHz radio setup is nice. I use RC car radios and modify the throttle so it goes all the way to zero instead of having a neutral point at 40%. You can use a cheap airplane radio for much the same effect (and you can go fly RC with it, too, if you're of questionable tastes).

944_Jim · « **Reply #6 on:** April 23, 2023, 04:13:39 PM »

Thanks Mr.Steve,

I see I provided a broken link...jumping in from their homepage and re-redrilling through menus got me what I was trying to refer to.

Yes, the sport system is out of stock. However, It does provide a parts list with specs. A package can be assembled of like-equipment found through other vendors.

In short, this is still of value for learning/procurement...even if inconvenient

Ken Culbertson · « **Reply #7 on:** April 23, 2023, 04:48:01 PM »

Let me clarify a bit. I plan for this to go into a full body, full pattern stunt plane of 1/2a proportions that I will design around the power plant. I estimate a 30-32" span and as light as possible. It will need to fly for 5.5 min. I am guessing a 3s battery and a motor that will output the equivalent of a Norvel .061. I won't need a fancy esc/timer, just run time and RPM and none of it needs to be new if anybody has a set laying around.

Ken

john e. holliday · « **Reply #8 on:** April 23, 2023, 06:30:03 PM »

[
https://www.stevensaero.com/
~~https://www.rsmdistribution.com/categorymenu.php?cat=28~~ bad link

Good luck...and please share what you find and what you think with respect to the little guys.
[/quote]
Forget Stevens Aero. I have one of thir kits that I wanted for the grandkids to learn on. Half the power package is shown out of stock. Have sent messages to them and no response. I am about ready to put a Black Widow on the plane.

Brent Williams · « **Reply #9 on:** April 23, 2023, 06:36:15 PM »

Ken, for your application, I would look at what guys are using in the electric 1/2a pathfinder.

Paul Wescott · « **Reply #10 on:** April 23, 2023, 07:39:33 PM »

Quote from: Ken Culbertson on April 23, 2023, 04:48:01 PM

Let me clarify a bit. I plan for this to go into a full body, full pattern stunt plane of 1/2a proportions that I will design around the power plant. I estimate a 30-32" span and as light as possible. It will need to fly for 5.5 min. I am guessing a 3s battery and a motor that will output the equivalent of a Norvel .061. I won't need a fancy esc/timer, just run time and RPM and none of it needs to be new if anybody has a set laying around.

Ken

Ken - Larry Renger gave me the parts list below a while back. Larry and flying buddy Andy Borgogna flew an electrified 1/2A Pathfinder very successfully several times at Whittier Narrows and once inside the Tustin Calif blimp hangar (video has been linked several times before).

Larry has designed several large 1/2A airframes (Skyfire, Skysport {RSM}, etc) and demands stunt pattern performance of all of his planes.

Hacker A20-34 brushless motor (operational / prop data here: https://flybrushless.com/motor/view/261 )
850mah 3S (11.1 volts) LiPo battery (about $13 retail right now)
6x5.5 APC prop
12,500rpm
42’ lines

Hacker makes high-end long-lasting motors with pricing to match. I’m sure you can look up the specs and substitute a less expensive one, cross-reference chart attached below (see the very last line).

Timer: use the lightest one that has the features you want. RPM governor types probably not light enough.

Let me know if any of this helps…

Paul W.

Dave Rigotti · « **Reply #11 on:** April 24, 2023, 07:38:48 AM »

Here's MY 1/2A electric setup:
Cobra 2204/32 1960kv motor
Tempest 15A ESC
Thunder Power 3S 750mah lipo
APC 5.5 x 4.5 pusher prop
CircuitFlyer DIY timer (has a thread here on SH about it).

This give me @95 watts in a 7 1/2oz ready to launch airplane. OR @200 watts per pound......

For stunt you may want to try a 6x3 or something similar.

Ken Culbertson · « **Reply #12 on:** April 24, 2023, 10:49:00 AM »

Quote from: Dave Rigotti on April 24, 2023, 07:38:48 AM

Here's MY 1/2A electric setup:
Cobra 2204/32 1960kv motor
Tempest 15A ESC
Thunder Power 3S 750mah lipo
APC 5.5 x 4.5 pusher prop
CircuitFlyer DIY timer (has a thread here on SH about it).

This give me @95 watts in a 7 1/2oz ready to launch airplane. OR @200 watts per pound......

For stunt you may want to try a 6x3 or something similar.

Thanks Dave. I think that is what I will order. When you say 7 1/2 oz ready to fly that doesn't leave much for the airframe!

Ken

Dave Rigotti · « **Reply #13 on:** April 24, 2023, 01:19:10 PM »

About 50/50 split. 3.7 power, 3.8 airframe.

Quote from: Ken Culbertson on April 24, 2023, 10:49:00 AM

Thanks Dave. I think that is what I will order. When you say 7 1/2 oz ready to fly that doesn't leave much for the airframe!

Ken

Tim Wescott · « **Reply #14 on:** April 24, 2023, 01:30:06 PM »

Ken, you're already there but if you're designing the plane get the entire electronics bay built and tested out (including getting the batteries in and out) then build the rest of the plane around it.

Kind of like starting your slime-powered PA ship with the motor crutch, and working outwards from there.

Ken Culbertson · « **Reply #15 on:** April 24, 2023, 03:46:56 PM »

Quote from: Tim Wescott on April 24, 2023, 01:30:06 PM

Ken, you're already there but if you're designing the plane get the entire electronics bay built and tested out (including getting the batteries in and out) then build the rest of the plane around it.

Kind of like starting your slime-powered PA ship with the motor crutch, and working outwards from there.

I did that on Endgame III then I switched to some custom shaped Li-ion batteries that didn't fit, then I ran the Canard pushrod through the bay I had built for the ESC and when I repositioned it in the lower cowl I blocked off access to the timer which I had to move to where the Esc was. My point - planning ahead is not my strength!

Ken

Tim Wescott · « **Reply #16 on:** April 24, 2023, 06:38:14 PM »

Quote from: Ken Culbertson on April 24, 2023, 03:46:56 PM

I did that on Endgame III then I switched to some custom shaped Li-ion batteries that didn't fit, then I ran the Canard pushrod through the bay I had built for the ESC and when I repositioned it in the lower cowl I blocked off access to the timer which I had to move to where the Esc was. My point - planning ahead is not my strength!

Ken

Funny, we're having a discussion at work where one camp wants to build in features that we'll need "someday", and the other camp is taking the position that "by the time someday comes, everything will be different". The problem with being experienced is that I've been in each one of those camps before, and while in each one I've been stunningly right, and while in each one I've been stunningly wrong.

So when those discussions pop up I mostly cook up popcorn and try to get a ringside seat.

Leonard Duke · « **Reply #17 on:** April 28, 2023, 03:21:19 AM »

I flew last season on a Brodak system that came with the timer, esc, 6x4 prop and a battery. With the 2s battery it seemed a bit less powerful than a typical cox reed valve. Looking in their old print catalog I saw that they used to sell the same kit with a 3s motor, so I ordered 3s batteries and a lower pitch prop, now it is much faster. The 3s batteries get good and warm.

The Brodak kit doesn't regulate RPM, the RSM kit does. Brodak uses a 6" prop, RSM, 7". Makes me suspect the RSM 3s kit is more powerful than Brodak's.

The Brodak $110 system was out of stock last fall, so I ordered myself a second setup out of the separate parts.

John Skukalek · « **Reply #18 on:** April 28, 2023, 07:55:52 AM »

My experience with the Brodak 1/2a combo was very similar to Leonard's. Needed to replace the 2s battery with a 3s battery to have enough power.

Ken Culbertson · « **Reply #19 on:** April 29, 2023, 06:10:54 PM »

Has anybody used these? The price is almost too good to be true but I am not looking for a NATs quality PA system here, just a fun 1/2A Size. Coupled with a Huben FM9-0 this might be worth trying.

https://www.ebay.com/itm/404211855874?hash=item5e1ce77202%3Ag%3A5mQAAOSwzONkGcqu&amdata=enc%3AAQAIAAAA4G8pVZTnFdq%2FVtHeo7a3G9HedDNSTzb%2FG4jbd3yiiG8ZYtdm%2F0ilXhCbtrBkHq2r7%2BgCKP0mIF5jI2OwDdwGWHov7ZXfwNc4Ar2zjJTzgZLqswrS4aSRmGpk95TB97WD1QnNmaGmTWV%2Fzbpyi%2FERnxkfiCyYMSbTXITXhRgVCPeqdp88GKorNf9YNbhs0xG14pIkFBRSECdLp2oF1xknXmZeTtHSa%2Bv4OUFYpP8oTPv38MdQKVrjZMZVzGyVPLaPwTKqPspq%2FeI8uE5YFX5UQSji0fMDYeFr6k889PTFgvI7%7Ctkp%3ABFBM7qix9_lh&LH_ItemCondition=3

Ken

Dave Rigotti · « **Reply #20 on:** April 29, 2023, 06:55:45 PM »

30A ESC is unnecessary and just adds weight...just sayin'

Ken Culbertson · « **Reply #21 on:** April 29, 2023, 07:33:31 PM »

Quote from: Dave Rigotti on April 29, 2023, 06:55:45 PM

30A ESC is unnecessary and just adds weight...just sayin'

You are right. I found some 20a that only weighed 3.9g. Hard to believe. The one with this combo was 37g but basically free. Same motor w/0 the combo is the same price. One of those things that makes you what to say "Huh?"

Ken

Pat Johnston · « **Reply #22 on:** May 01, 2023, 09:18:16 AM »

Ken,
I have a few designs for 1/2A electric. The first is the Shark 202. Then came along the Ringmaster, Magician, and Epiphany. All are close to 200 squares. Very nice size for 1/2A’s. They have both IC and electric plan setups available. The Shark 202 weighs under 10 ounces RTF. I show all the parts needed on the plans. Any of these profiles would be an excellent way to easily get your feet wet in this way. See my thread on my 1/2A Airforce on this forum. 1/2A electrics can be a ball.
Pat Johnston
patsplans@yahoo.com