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Aug 08, 2019, 09:47 PM
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Discussion

New guy needs help with Sterling Corvette


Greetings all. Not new to hobbies (I have dabbled in everything from slot cars to electric trains to steam engines to pinball machines) however I am a novice when it comes to R/C . I had always wanted a vintage R/C wooden boat to play around with and now that I'm retired and living near the water I figured it's as good as time as any.
I spotted this vintage-built Sterling Corvette with old tube type radio gear and Pittman Panther motors and fell in love.

I am completely unfamiliar with the way these operated but it seems by studying the wiring that the receiver must have been 2-channel and controlled both the steering and throttle. The electric motor setup which controls the rudders is quite intriguing and seems to incorporate some type of ratchet mechanism. While I love the nostalgia associated with all this old equipment I'm guessing that it would be impractical to try and find a matching transmitter run it this way today.

If at all possible I would like to preserve the originality and leave all or most of the original running gear and radio gear intact while retrofitting a modern motor control and (1/4 scale?) servo for rudder control that will override it.

The Pittman Super Panther motors are designed to run on 3-6 volts. There are various old dry cell battery holders in place for the radio gear and lights as well as a wood framed pocket that used to hold some type of large battery approx 4" square and utilizing the 9-volt battery style clips.

What would be a suitable modern power supply/battery that could operate both the 3-6 volt Pittman motors as well as the receiver and servo ? What about the new radio and receiver. Seems maybe a single 1/4 scale servo would be good for rudder control. What about a motor controller? How many channels ? Do I control both motors in tandem or individually ? Is reverse necessary ?
Sorry for all the barrage of newb questions. My son is flying in next week, he's a little more knowledgeable than I am with electronics and I'd like to work on it with him and try to get it sorted out to the point where we can run it.

Thanks in advance for your patience and advice.

Gerry
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Aug 09, 2019, 02:17 AM
Me and a guy with a mustache
babblefish's Avatar
Great find! I love the vintage electronics inside. It looks a lot like a very early "galloping ghost" type system using a super regenerative receiver. Trying to find a transmitter and correct "B" battery for the tube's 67.5V plate voltage, "C" battery (usually 4.5V) for the tube's grid voltage, and 1.5V "A" battery for the tube's filament would not be too difficult. If it were my boat, I'd leave all the vintage electronics installed, just disconnect the rudder actuator from the rudder. Buy a modern 2-channel 2.4gHz radio system that comes with a servo. That's not a big boat so a "standard" size servo should have more than enough power for the rudders, no need for 1/4 scale stuff. I suspect those two motors won't draw very much power so get an electronic speed controller (ESC) meant for a 1/10 scale RC car (so you'll have forward and reverse speeds) and rated for use with brushed motors. Something that can handle around 20 amps or more should be adequate. Battery wise, a 6V gel cell rated for around 7Ah is a good place to start. You could even use a regular 6-cell NiMh battery pack meant for RC car use, but your run time will be shorter and you'd have to add static ballast. I'd install the modern electronics in such a way that they're hidden from view so onlookers will think the boat is still running with the vintage equipment.
Good luck with the resurrection and please keep us up to date on how you're coming along.

Just for fun: https://en.wikipedia.org/wiki/File:E...model_boat.jpg

And this might interest you: https://www.rcgroups.com/forums/show...n-2-4GHz-radio

And this:
Graupner Kinematic magnetic actuator (1 min 59 sec)


I feel old...
Last edited by babblefish; Aug 09, 2019 at 05:34 AM.
Aug 09, 2019, 07:50 PM
Registered User
Thread OP
Wow thanks so much for your detailed reply and associated links. I have a much better grasp now of how it worked and what I need to do. I am really fascinated by the fact that the Kinematic actuator is/was capable of operating both the rudder and the motor functions simply by finessing the way you "blipped" the single channel transmitter.. I say "simply" but it seems like it would take some amount of practice to toggle through the sequence and get the boat to go where you want it to go. Would not want to try that actuator in an airplane (or even a fast boat) !
I really like your idea of hiding the modern equipment so it appears to be running off the vintage gear. I think that will be my game plan moving forward. It kinda feels like "cheating" but until I educate myself further in the hobby I think it best for both man and boat if I run it with modern electronics.
That old Eveready "Nine Lives" battery is so cool. I saw where the builder had penciled "67.5" in the battery hold but thought to myself "that can't be the voltage". Would be cool to find one of those old battery boxes and fit the new power supply inside of it.

I've attached some additional pictures of the boat in case you're interested. Some of the detail is terrific like "planking" on the deck instead of just plain wood. Notice the small rods protruding from the side of the hull around mid-ship. They each operate a slide switch mounted to the inner bulkhead.

I acquired the boat from an antique dealer who bought it from the family of the original owner. This is was the history that accompanied the boat:

" I bought the boat from a lady whose dad built it in the late 50's - early 1960's. She remembers him and his love of this boat when she was a kid. He passed away in January and her and her husband drove from Cleveland to clean out his home on Lake Winnipesaukee in New Hampshire. She really liked the boat but told me she would end up just storing it away and she would rather it be in the hands of someone who loves it as much as her dad did.

We'll be working on it this coming week . I will keep you posted.
Thanks again !
Gerry
Aug 09, 2019, 09:40 PM
Me and a guy with a mustache
babblefish's Avatar
Thanks for the wonderful back story on your boat. The gentleman who originally built and owned it did a fantastic job. I'll bet he was proud of it, and rightly so.

Kinematic actuators were used in RC airplanes back in the day except those were smaller and lacked the motor function. RC airplanes back then were powered by either nitro or diesel fuel and sometimes regular gasoline.

So you want to use an Eveready battery to put the new electronics in, good idea. Here you go. Scale it to whatever size you want and print it out on heavy card stock with a color laser printer (not inkjet) and it'll look great.

Enjoy.

All images courtesy of: http://www.greenhillsgf.com/Project_63V_BatteryKit.htm
Last edited by babblefish; Aug 09, 2019 at 10:03 PM.
Aug 10, 2019, 11:54 AM
Registered User
Thread OP
Thank you for the compliments and thanks much for the vintage battery case printouts . As usual with all my good ideas, somebody else had it first !

Gerry

As an aside, some of the (pot metal? lead ?) fittings are coming loose from the hull. Before I lose one at sea, what it considered to be the superior adhesive for attaching metal to wood on these models ?
Aug 10, 2019, 09:54 PM
Me and a guy with a mustache
babblefish's Avatar
Hmm, since no one else is responding, guess I'll jump in again.
The first thing you'll want to do is to clean off all the old glue on both surfaces and any corrosion that might be on the fittings. I would then refinish the fittings in whatever way you like (paint, plating). If painting, it would be a good idea to use a self-etching primer first then the color coat and if it were me, a clear coat on top.
As far as reattaching the fittings, most would probably suggest a thick or medium CA glue and a spritz of accelerator. While this will work, I've found that in a wet environment along with lots of exposure to the sun, the CA glue may eventually break down and the fittings will pop off again. Of course there are those who will say that's never happened to them and that may be true, but I'm just speaking from my own personal experience. YMMV.
There are "rubberized" CA glues available that may survive better than regular CA because it will allow for a certain amount of thermo expansion and contraction without failing. This type of CA is available in either clear or black. I've used the Bob Smith brand for gluing RC tires to their rims and it works pretty well.
The second choice would be epoxy glue. A little more fiddly to use but strong.
Some people will drill small holes in the fittings in order to insert a small copper or brass pin which would then be inserted into matching holes in the wood structure for a more secure attachment.

-Wes
Aug 11, 2019, 04:46 AM
Registered User
For background reading you might want to look at this site - which, amongst other things, has a Kinematic actuator working, and a full description of how single-channel operates. The site also provides 'single channel emulators' - kit that turns a modern 2.4Ghz radio into a single channel more reliably than by using an old valve radio...

http://www.singlechannel.co.uk

Oh, and please don't throw the original electronics away. It's worth money to a collector...
Aug 11, 2019, 05:32 AM
Registered User
First choice glue would be EPOXY, ca is water soluble.

Regards Ian.
Aug 11, 2019, 08:17 AM
Me and a guy with a mustache
babblefish's Avatar
Quote:
Originally Posted by Circlip
First choice glue would be EPOXY, ca is water soluble.

Regards Ian.
Normally I would agree with you but there are many different formulations of CA glue these days. The type used in the medical profession is mostly water soluble as far as I know. As many of you are aware, CA type glues were first developed during war time for use on the battlefield as an emergency and quick suture so as such it had to be water soluble so that it could dissolve away as the wound healed. Nowadays, there are some highly water resistant CA glues available such as the Bob Smith Industries rubber toughened glues that I mentioned earlier. You can get more information here:

http://bsi-inc.com/hobby/insta_flex_plus.html
http://bsi-inc.com/hobby/ic_2000.html

I haven't used them yet on any of my boat models but I can tell you this, boiling water wouldn't remove tires off of plastic rims when I used these glues. I had been able to boil tires off when I used standard CA glues many years ago. I have a model boat that was commercially made overseas and the pot metal fittings were CA glued to the wooden hull. I'm not sure what kind of CA they used other than that it was clear. Anyway, most of the fittings over time have popped off the boat. Highly annoying. I'll probably try some of the rubberized CA to glue them back on.
Aug 11, 2019, 01:24 PM
Registered User
As many of you are aware, CA type glues were first developed during war time for use on the battlefield as an emergency and quick suture...

It was first created and examined as a plastic for gun sights during WW2, but rejected as it was too sticky. then later re-examined as a plastic for jet canopies in the 1950s, and at that point commercial possibilities were realised, and it was developed and marketed as a glue. From that commercial application came all the uses we know today, including the medical ones...
Aug 11, 2019, 06:16 PM
Registered User
Thread OP
Rest assured the vintage R/C gear is staying in the boat !

Anyone care to venture a guess what the full load current draw would be on the 6V Pittman Super Panther motors ?

Does the fact that the end of the prop shaft tube is above the waterline keep the water from coming in ? I'm thinking the spinning shaft could still scroll the water up the tube. Did they use some kind of waterproof grease inside the tube or did they run them dry ?

Thanks
Last edited by Seaview24; Aug 11, 2019 at 07:41 PM.
Aug 12, 2019, 12:46 PM
Registered User
Above the waterline is the crucial thing. A decent thrust washer at the prop would be fairly watertight when power was on.

Packing with grease will slow the boat an awful lot. A bit of oil on the bearings is fine. Some boats had an oil feeder spur for the prop tube....
Aug 12, 2019, 07:42 PM
Registered User
Thread OP
Thank you Dodgy, I'll see about fitting a proper thrust washer and adding a drop of oil to the tubes.
Aug 13, 2019, 06:02 AM
Registered User
And when you use Epoxy, use the slow setting one, NOT the five minute types.

Regards Ian.
Aug 13, 2019, 07:47 AM
Registered User
glgirvin's Avatar
Hi Guys, I have used one or two ways for attaching fittings. If the fitting has a good size surface area, I like to use clear silicone sealer. ( easy to remove if necessary, such as for changing light bulbs)On smaller fittings and attaching window panes, I have found that the Gorilla clear glue works well. I will probably use it for the stanchion post on my 63s for the railing. Thank you,Gary


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