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Electric Retracts - Modifying existing Air/Servo-operated Retracts

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Old 11-21-2009, 07:41 PM
  #1
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Default Electric Retracts - Modifying existing Air/Servo-operated Retracts

Well, after having given up on Lado... ([link]http://www.rcuniverse.com/forum/m_8425919/anchors_8425919/mpage_1/key_/anchor/tm.htm#8425919[/link]) ,the DIY guy that I am... I designed my own DIY version last night...

Here's a vid of the first prototype.... used a miniature 50:1 gear motor attached to a pc. of 4-40 threaded rod that pushes/pulls the existing mechanism of an older (Hobbico?) servo-operated retract mechanism. My next project will be retrofit actuators for my Robart 630 retracts (easier actually)... but still awaiting a few custom couplers my Dad is machining for me... Next task is to design the controlling electronics (will use a 8-pin PIC interfaced to an H-bridge with current sensing circuitry to sense end positions... no limit switches needed). Might soon be looking for a CNC manufacturer! [8D]

[youtube]http://www.youtube.com/watch?v=y1-hInYnsw0[/youtube]
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Old 11-21-2009, 08:15 PM
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Default RE: Electric Retracts - Modifying existing Air/Servo-operated Retracts

Hey... I'm curious.... how many of you would rather retrofit existing air/servo-controller retracts (i.e. Robart, Century, etc...) with an actuator replacement (remove air cylinder & replace with electric actuator).... rather than buying a complete set that is electrified? Just trying to see if there is a market/need for just the actuators.

If any one also has any comments/suggestions... please reply.
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Old 11-21-2009, 08:31 PM
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Default RE: Electric Retracts - Modifying existing Air/Servo-operated Retracts

I’m very interested in several sets of them, you better get to work and sort them out, just add customer service and you will have LADO beat hands down & customers will beat a path to your door
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Old 11-21-2009, 08:55 PM
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Default RE: Electric Retracts - Modifying existing Air/Servo-operated Retracts

I think there will be a large market Tom.

Go for it!
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Old 11-21-2009, 10:49 PM
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Default RE: Electric Retracts - Modifying existing Air/Servo-operated Retracts

Looks good so far...just don't forget to add a torque limiter or such so that if the gear do hang up somehow, they shut down rather than burn out...or is that what you mean when you mention a current sensing circuit?
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Old 11-21-2009, 11:20 PM
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Default RE: Electric Retracts - Modifying existing Air/Servo-operated Retracts

Breaking news from Doug at Lado's himself...

http://www.rcuniverse.com/forum/m_84...tm.htm#9269674

Not sure how this will ensure a reliable supply in the future....
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Old 11-22-2009, 12:03 AM
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Default RE: Electric Retracts - Modifying existing Air/Servo-operated Retracts


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ORIGINAL: jim pettis

Looks good so far...just don't forget to add a torque limiter or such so that if the gear do hang up somehow, they shut down rather than burn out...or is that what you mean when you mention a current sensing circuit?
Jim,
Yes.... my idea of a current sensor (built into H-bridge chip I plan to use) will hopefully allow me to sense increase current at both ends of throw... motor would hence stop automatically. It would also stop any time it senses an increase in current due to unexpected binding (i.e. obstacle). I ordered a sample chip ([link=http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=MC33887&fsrch=1]Freescale MC33887[/link]) and will experiment more when it comes in. Some PIC code will also have to be written but should not be all too difficult... so I hope!

Right now, I'm thinking of seperating the controller from the mechanism... not only to save space in/on the retract, but to also protect the controller from the elements, sheilding it inside the aircraft. Plus it probably wouldn't be too hard to have one servo controller board control MANY servos for various applications (maybe even with onboard options such as speed, stagger, delay, etc... functions). I also pondered the idea of auto retracts where when the aircraft (controller) senses altitude (via sensor) and when a preset altitude is reached, the retracts automatically are triggered, bringing up the gear.

I am more of a small DIY parts guy (supply small elec gadgets, kit parts, etc...) so if any one else is interested is a possible partnership of some type... please PM.
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Old 11-22-2009, 12:13 AM
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Default RE: Electric Retracts - Modifying existing Air/Servo-operated Retracts

Quote:
ORIGINAL: jim pettis

Breaking news from Doug at Lado's himself...

http://www.rcuniverse.com/forum/m_84...tm.htm#9269674

Not sure how this will ensure a reliable supply in the future....
Jim,
This is sooooo funny.....

Quote:
....

One other thing…. Who ever is calling and filling up my voicemail is really out of line. I have contacted my phone company and they will be tracing these callers.

Thanks,
Doug - LADO Tech

Now this is just a guess... It might in fact be his "customers" looking for the gear they paid for months ago...
Just a hunch....
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Old 11-22-2009, 07:39 AM
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Default RE: Electric Retracts - Modifying existing Air/Servo-operated Retracts



Quote:
....

One other thing…. Who ever is calling and filling up my voicemail is really out of line. I have contacted my phone company and they will be tracing these callers.

Thanks,
Doug - LADO Tech

Now this is just a guess... It might in fact be his ''customers'' looking for the gear they paid for months ago...
Just a hunch....
[/quote]


I had the same exact thoughts...hmm, wonder if he considers my daily calls for info harassing as well. Good thing I leave a call back number every time. Will save the "phone company" some time there.
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Old 11-22-2009, 01:20 PM
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Default RE: Electric Retracts - Modifying existing Air/Servo-operated Retracts

I love it! Now I have a use for all those old can electric motors I have about the shop!

Following this thread with a lot of interest. Lots of questions, but will hold them for now.

Love it!

Tommy D
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Old 11-22-2009, 03:25 PM
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Default RE: Electric Retracts - Modifying existing Air/Servo-operated Retracts

A replacement for the air cylinder sounds like the way to go.
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Old 11-22-2009, 08:01 PM
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Default RE: Electric Retracts - Modifying existing Air/Servo-operated Retracts

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ORIGINAL: kodi7

A replacement for the air cylinder sounds like the way to go.
Yeh, that's what I first thought... there really is nothing wrong with current retract manufacturing Co. out there... a simple air cylinder replacement sounds like the easiest and most economical solution. I'm really surprised ppl like Robart has not started selling their gear in electric versions... time will tell I guess.

I hope to find some time this week to tinker a bit with my 630 Robart air-retracts... have some ideas to prove out... and once I get these 630s mod'd, I'll try to post some details/pics.

Any one else looking to get involved in working out the CNC/manufacturing details?? [8D]
As a minimum, a clam-sheel style aluminum case for the motor would need to be designed... got some ideas to share but I'm not a big-time CAD guy...

p.s. I also need a little help with some other gear that is out there, which I don't have in hand to observe....
I'm curious in regards to the type of mechanics that is used which pulls/pushes the mechanism. My Robarts use a steel cylinder that rides along to CNC slots milled into the two sides of the mechanism, which in turn rotates/locks the gear up and down. The air cylinder's rod, that extends or retracts, is then attached to this steel cylinder (the rod threads into the steel cylinder... usually with red loctite to lock it in good). I'm curious is any one knows the thread/size of this controlling rod, as the electric retract mechanism will need to use the similar threaded rod (avoiding having to re-tap the steel control cylinder). If I have time,... I'll psot some oics of what I am talking about... The other option is to provide various cylinder of various sizes and various threaded holes for the threaded control rod... I'm certain these are probably model-specific...
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Old 11-23-2009, 12:56 AM
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Default RE: Electric Retracts - Modifying existing Air/Servo-operated Retracts


Quote:
ORIGINAL: _Tommy D

I love it! Now I have a use for all those old can electric motors I have about the shop!

Following this thread with a lot of interest. Lots of questions, but will hold them for now.

Love it!

Tommy D
Unfort, those old can motors might be a bit too large for this app...
These gear motors I'm using are built will all-metal gears... and tiny as heck (but alot of torque)

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Old 11-23-2009, 10:14 PM
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Default RE: Electric Retracts - Modifying existing Air/Servo-operated Retracts

They look a lot like the old, what we used to call J250s motors. Had a bucket full of them at one time =)
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Old 11-23-2009, 10:48 PM
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Default RE: Electric Retracts - Modifying existing Air/Servo-operated Retracts

So whats a motor gear box unit like that cost and where do you get one?

The key element here is going to be the electronics I think.

Lots of guys could do their own motor gear box mods - if they had a source for the parts.

The electronics will stump most of us though.

Probably the majority will want a plug-n-play setup though.
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Old 11-23-2009, 11:09 PM
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Default RE: Electric Retracts - Modifying existing Air/Servo-operated Retracts

$18.99 Robot Marketplace

http://www.robotmarketplace.com/products/IL-SAN50.html

There are cheaper suppliers if you want to buy in bulk. Its a fairly common antweight (combat robot class) drive motor. Different gear reductions are available.

For the electronics, just dismantle a standard size servo. Remove the motor and wire in the new gearhead motor. Remove the potentiometer and wire in a new 5k linear potentiometer that is attached to the nut of the retract mechanism. Seal the servo board with heatshrink and some hot glue. Instant proportional retract mechanism that can plug right into your receiver. You can program the endpoints with your transmitter.
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Old 11-23-2009, 11:13 PM
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Default RE: Electric Retracts - Modifying existing Air/Servo-operated Retracts

The gear motor is manufactured by Sanyo. Part number 12GN-0348. You may search for "12mm gear reduction motor" to find similar products.
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Old 11-23-2009, 11:28 PM
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Default RE: Electric Retracts - Modifying existing Air/Servo-operated Retracts

i would sure be interested if you make them for giant scale, got a couple sets of robarts that would be great electric
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Old 11-24-2009, 01:40 AM
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Default RE: Electric Retracts - Modifying existing Air/Servo-operated Retracts


Quote:
ORIGINAL: hands without shadows

$18.99 Robot Marketplace

http://www.robotmarketplace.com/products/IL-SAN50.html

There are cheaper suppliers if you want to buy in bulk. Its a fairly common antweight (combat robot class) drive motor. Different gear reductions are available.

For the electronics, just dismantle a standard size servo. Remove the motor and wire in the new gearhead motor. Remove the potentiometer and wire in a new 5k linear potentiometer that is attached to the nut of the retract mechanism. Seal the servo board with heatshrink and some hot glue. Instant proportional retract mechanism that can plug right into your receiver. You can program the endpoints with your transmitter.

Im not sure Im following you on the servo parts use. These are going to need to turn several full 360 degree revolutions to go from UP to DOWN.

Oh wait - thats what the linear pot is for?

If Im understanding you thats a cool suggestion!

That would work well for everything except the gear getting jammed. A current sensor would still be needed I think. Or at least a nice addition.
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Old 11-24-2009, 11:13 AM
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Default RE: Electric Retracts - Modifying existing Air/Servo-operated Retracts

Yup... you guys are right... Sanyo gear motors they are, with a 50:1 ratio. This allows me to spin my 4-40 rod (that drives the retract actuator) at such a speed that it takes roughly 4-5 seconds to retract or deploy... Many Robotics outfits sell them.... and the ones I have were purchased from Pololu.com

As for the electronics, you certainly could use scrap servo parts but there is really no reason to make these "proportional", using a feedback pot. To sense limits, I plan to use the increase in current when it reaches both ends, rather that limit switches and/or a feedback pot. Attaching a potentiometer to this mechanism is not all that easy either... look at my setup and you'll see what I mean... no easy way to connect to the nut being driven my the threaded rod.

Now,... the bad/good news, I recently got contacted by a few manufacturers/reps who are very interested in this idea (certainly can't say names) but I can tell you, there is definitely the possibility that these retrofit actuators could be on the market faster than some think. Some probably don't know this but some of the big-name retract Co. are also looking into selling their gear but with electric actuators... in fact some one mentioned that a few of them might had already contacted Lado re: supplying them the actuators for their use (possibly his new bussiness plan). The bad publicity Lado took the last 3-4 months might had ruined this coop... and it now appears they might be looking for other solutions... possibly purchasing the design and bringing the manufacturing in-house.

So... bottom line... If I decide to work with these fellas... you won't see any more posts here re: my DIY retracts effort unfort.
...time will tell...
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Old 11-24-2009, 12:05 PM
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Default RE: Electric Retracts - Modifying existing Air/Servo-operated Retracts

Good luck with it Tom!!

I would still like to see an offering of DIY components. I dont think that would cost much in the way of sales. There are not that many guys who would do the work on their own.

In particular, I would like to see a current sensing cut off device. I still think thats the key stumbling block to DIY'ers.
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Old 11-24-2009, 12:35 PM
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Default RE: Electric Retracts - Modifying existing Air/Servo-operated Retracts

Sure Larry... I'll certainly keep that in mind for the DIY'ers.
After I get some electronics working... I'll try to post some vids and some specs, etc...
Like you said, the electronics are quite an important part of these... it could make or break the idea actually...
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Old 11-25-2009, 08:22 PM
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Default RE: Electric Retracts - Modifying existing Air/Servo-operated Retracts

Well... I was able to easily modify one of my large-scale Robart retracts to operate electrically rather than via air....

Here's the first vid..... works amazingly well for a large/heavy gear mechanism... that's a 4" wheel there... (this was pulled from my 1/4 scale A6M5 Zero).... can't wait to start working the electronics....

[youtube]http://www.youtube.com/watch?v=pILrwAKbSIY[/youtube]

Cool or what? [8D][8D]
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Old 11-25-2009, 09:49 PM
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Default RE: Electric Retracts - Modifying existing Air/Servo-operated Retracts

That is super cool!
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Old 11-26-2009, 07:35 AM
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Default RE: Electric Retracts - Modifying existing Air/Servo-operated Retracts

I'll take 2 thank you. Looks like a ton of power, and I actually like the speed compared to the Lado. Nothing like a dead stick and your gear taking 10 seconds to drop.....

It would be great if these or something like it were READILY available. I'm getting ready to put together the Hangar 9 Spitfire, and will have to deal with undersized gear wire, servo set up, etc. Would be much happier tossing a pair of Robostruts and electric retracts in.

Good luck.
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