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Jan 25, 2019, 02:52 PM
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Vintage Mini Mambo


Trying to put this in flying condition using original escapement and Futaba relayless receiver. The escarpment seems to work when I connect 3 volts. But, it needs new rubber. I am looking for help in determining a transmitter that will work. The receiver is on 27.145 . Any help or ideas woul be appreciated.

Thanks,
Bob
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Jan 25, 2019, 04:28 PM
B for Bruce
BMatthews's Avatar
You could simply daisy chain some #32 rubber bands together to make a new rubber motor. Plus you'll want to find an old hand crank hand drill to modify into a winder.

Can't help much with the Tx. But there are module and options for turning modern 2.4 rigs into systems that act like an escapement.

There are also "switch" modules for running lights or other things on model boats which you could plug into the landing gear channel and run from the landing gear switch on a modern Tx. Or in some cases you can program a channel in the Tx to any switch on the panel. If there's a push button you can use for that then you could set that up.

Outside of that you're going to be looking for a vintage Tx. that still functions. Or if you can find an old Controlaire Galloping Ghost transmitter there are switches on the board which switch off the pulsing and the high throttle button becomes a simple keying switch for this sort of use.... I only know that because I used to have one of those systems.
Jan 25, 2019, 04:38 PM
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Quote:
Originally Posted by BMatthews
You could simply daisy chain some #32 rubber bands together to make a new rubber motor. Plus you'll want to find an old hand crank hand drill to modify into a winder.

Can't help much with the Tx. But there are module and options for turning modern 2.4 rigs into systems that act like an escapement.

There are also "switch" modules for running lights or other things on model boats which you could plug into the landing gear channel and run from the landing gear switch on a modern Tx. Or in some cases you can program a channel in the Tx to any switch on the panel. If there's a push button you can use for that then you could set that up.

Outside of that you're going to be looking for a vintage Tx. that still functions. Or if you can find an old Controlaire Galloping Ghost transmitter there are switches on the board which switch off the pulsing and the high throttle button becomes a simple keying switch for this sort of use.... I only know that because I used to have one of those systems.
Thanks. I really would like to keep the vintage receiver and escapement. I know that some earlier rc toy boats and cars used 27.145 . Dont know if it might work here, but I long passed tossed out my old toy rc car stuff. Also thought about an old walkie talkie on CB band. But CB didnt use 27.145.
Jan 25, 2019, 07:57 PM
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Your radio looks like my old Futaba F-66 system. These show up occasionally on eBay but due to age they often don't work. Capacitors dry up and transistors can corrode and it's rarely worth the effort to replace them (IMO.) Using a modern Tx and Rx will improve your chances of success. The escapement may need cleaning and lube to function properly. The rubber must be the right size, 1/8 or 3/16" width. Too many turns will prevent the relay from releasing the pawl. Too few turns and the escapement won't move the rudder. You need to wind before each flight because many button presses will use up the rubber turns.

Steve

Single Channel Escapement RC Flying (3 min 13 sec)
Jan 25, 2019, 10:26 PM
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Quote:
Originally Posted by mlbco
Your radio looks like my old Futaba F-66 system. These show up occasionally on eBay but due to age they often don't work. Capacitors dry up and transistors can corrode and it's rarely worth the effort to replace them (IMO.) Using a modern Tx and Rx will improve your chances of success. The escapement may need cleaning and lube to function properly. The rubber must be the right size, 1/8 or 3/16" width. Too many turns will prevent the relay from releasing the pawl. Too few turns and the escapement won't move the rudder. You need to wind before each flight because many button presses will use up the rubber turns.

Steve

https://www.youtube.com/watch?v=FB4faISZJd8
Many Thanks Steve. My first RC, in 1963 or so, was a larger Mambo on a single channel escapement. I have too many planes with modern radio's. I have no desire to fly this little jewel unless it is era correct. Yes, my receiver looks like yours. Is yours on 27.145 ? Do you know if the transmitters of this era had changable crystals?
I assume that the receiver is triggered by a carrier on frequency. Could any transmitter , on frequency ,work in this application ?
Jan 26, 2019, 02:47 AM
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Quote:
Originally Posted by duradad
Many Thanks Steve. My first RC, in 1963 or so, was a larger Mambo on a single channel escapement. I have too many planes with modern radio's. I have no desire to fly this little jewel unless it is era correct. Yes, my receiver looks like yours. Is yours on 27.145 ? Do you know if the transmitters of this era had changable crystals?
I assume that the receiver is triggered by a carrier on frequency. Could any transmitter , on frequency ,work in this application ?
The transmitter uses a carrier with a superimposed tone when the button is pushed. The receiver is a superregenerative type and does not have a crystal. There is a tuning coil with a moveable slug that you adjust with a non-conductive screwdriver so that the indicator lamp achieves maximum brightness when the transmitter is keyed. I'm pretty sure you can tune this receiver to work with any tone transmitter in the 27MHz band.

I have an old Ceto transmitter that works with this radio.

A bit more info can be found here:
http://www.airplanesandrockets.com/e...969-aam-p2.htm

Steve
Jan 26, 2019, 03:37 AM
B for Bruce
BMatthews's Avatar
Quote:
Originally Posted by duradad
Many Thanks Steve. My first RC, in 1963 or so, was a larger Mambo on a single channel escapement. I have too many planes with modern radio's. I have no desire to fly this little jewel unless it is era correct. Yes, my receiver looks like yours. Is yours on 27.145 ? Do you know if the transmitters of this era had changable crystals?
I assume that the receiver is triggered by a carrier on frequency. Could any transmitter , on frequency ,work in this application ?
The TX's back then most certainly used crystals. They'd have been soldered in place to the board but can be replaced easily enough to switch frequencies. But if the Rx is an old superregenerative type then it should be tunable to any Tx in the old 27 band.
Jan 26, 2019, 11:12 AM
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Thread OP
Quote:
Originally Posted by mlbco
The transmitter uses a carrier with a superimposed tone when the button is pushed. The receiver is a superregenerative type and does not have a crystal. There is a tuning coil with a moveable slug that you adjust with a non-conductive screwdriver so that the indicator lamp achieves maximum brightness when the transmitter is keyed. I'm pretty sure you can tune this receiver to work with any tone transmitter in the 27MHz band.

I have an old Ceto transmitter that works with this radio.

A bit more info can be found here:
http://www.airplanesandrockets.com/e...969-aam-p2.htm

Steve
Thanks again Steve. Great link. Was fun to revisit all the old radio brands of the day. I remember well, getting my first citizenship proportional in 1970 ! If you are interested in selling your radio, pls PM me.
Thanks, Bob
Jan 26, 2019, 11:44 AM
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Thread OP
Quote:
Originally Posted by BMatthews
The TX's back then most certainly used crystals. They'd have been soldered in place to the board but can be replaced easily enough to switch frequencies. But if the Rx is an old superregenerative type then it should be tunable to any Tx in the old 27 band.
Thanks. The receiver does seem to have a pot open to the front case, which I presume is for tuning.
Bob
Jan 26, 2019, 01:01 PM
Registered User
Bob,
EBay often has suitable transmitters, usually with no guarantee that they will work. Here's a pricey one from the same vintage and manufacturer.
Steve
https://rover.ebay.com/rover/0/0/0?m...2F202573005908
Jan 26, 2019, 03:08 PM
B for Bruce
BMatthews's Avatar
Quote:
Originally Posted by duradad
Thanks. The receiver does seem to have a pot open to the front case, which I presume is for tuning.
Bob
Not a pot though. If you were to open up the case you'll find that it's a waxed paper or phenolic tube with a "set screw" made from ferrite that moves up and down in the tube to adjust the tuning. And I'm going to guess that the other hole is for the small light bulb that mlbco mentioned.

And if you missed it you cannot use regular steel screw drivers to adjust the tuning. They need to be non magnetic. So make a little screwdriver from plastic, brass or aluminium. Or even some good hard wood. But plastic is generally better.
Jan 26, 2019, 11:22 PM
Balsadustus Producerus
I just picked up a Citizen-Ship TTX transmitter off ebay for around $45 shipped. It's on 27.255 but can be changed to any of the other R/C 27mc band channels if you can source a crystal. Anything along those lines will be OK for your application. You can also use a transmitter from Controlaire, Orbit, F&M, C&S, ACE R/C, Kraft or similar if you can't find one by Futaba. If you go that route, don't worry about which 27mc channel it's on, as the receiver can be tuned to match if it's superregenerative, which it probably is. If it's a 'superhet', you'll need to match crystals to make it work. Most of those will be tone-type transmitters. Avoid carrier-only transmitters as the receiver will be better able to reject interference using a tone, and probably won't respond to a carrier-only anyway. Ask the seller before you buy. If he doesn't know, and more-n-likely won't, ask here for a recommendation. Also, I've seen a few vacuum-tube type single-channel transmitters show up for sale occasionally, but would recommend you don't get one of those; while the 'B' batteries needed to run the tube(s) are available if you search around, they are rather expensive and generally don't last very long. Alternate ways of driving a vacuum tube exist but you really need at least a 'tech' ham license or better to be successful.

As mentioned above, there are a few components that do not age well, were weak when new and the values should be off-spec. If you look around, you can get the contact info for Jay Mendoza here on RCG, and he can pretty much make any of the older single-channel systems work. His contact info is also listed 'bout halfway down in the 'Specific Links' section of the

http://www.vintagercsociety.org/cms3/index.php/links

Another consideration, also mentioned above, is go the 2.4g route, using current tech to run the rudder. I currently have a Mills 74 powered Smeed 'Chatterbox' airplane using Phil Green's S/C R/O emulator in a mid-fifties Ace R/C Commander transmitter box. That's what is in store for my newly-acquired Citizen-Ship TTX, along with a modern FrSky 2.4 RF deck with a matching receiver. He designed his system for use with 'most any current servo and emulating how an escapement works, but if you want to use the existing escapement, visit Phil and Shaun's site at:

http://www.singlechannel.co.uk/

and look at the bottom edge of the red and blue Sharkface model picture, move to the right and see the

Mode Zero

link and sign up with the linked forum. Looking around, you'll find these modellers are doing the same as you, some using newer radios, some older ones and some have found a way to use the modern radios with actual escapements and having a real blast doing it. While you're there, check out the videos showing flying single-channel rudder-only at the Pontefract and other sites. There's quite a popular following in England for rudder-only. By the way, as said above you can link a few #32 rubber bands to drive the escapement, but a better choice would be strip rubber from a free-flight supplier, such as

http://www.faimodelsupply.com/produc...-sport-rubber/

and that will be a far better grade of rubber for what you're doing. They also sell a lubricant especially made for rubber that will help it age slower and last longer.

This might seem a bit involved at first blush but is actually not difficult at all.

Finally, as the Southwestern U.S. Executive Council member of the Vintage Radio Control Society, I would be remiss not to plug membership of that AMA Special Interest Group, as more assistance will be available there as well. Please feel free to ask for any help you might need

Please do let us know how you get on with this project.

PS,

It occurred to me FAI Model Supply might sell you miles more rubber than you need. For a smaller amount, try Peck-Polymers' packages of 16 feet at:

www.peck-polymers.com/rubber
Last edited by Balsabird; Jan 27, 2019 at 12:39 AM. Reason: Added supplier option.:)
Jan 26, 2019, 11:31 PM
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Thread OP
Thanks Balsabird. You answered many of the questions I still needed to ask. Thanks also for the links. They will be very much appreciated.
Bob
Jan 26, 2019, 11:57 PM
Registered User
Dura-
Note that in the modern day rf environment, unless you are flying far away from urban areas, there will probably be so many stray signals on 27 mhz as to make a superregen receiver unuseable. Even in the country, someone a few miles away using a CB radio will knock you out of the sky.

A superhet receiver from the 60's in good shape can work fine, but I wouldn't trust anything other than a very small, light, and expendable model to that Futaba rx.

Just my .02.

Paul
Jan 28, 2019, 08:46 AM
Crash tests done dirt cheap!
Krumpel's Avatar
My first rc model was a Mini Mambo controlled by a Min-x transmitter and receiver on 27 mhz and a Bonner escapement. This was back in the 60s and I only got 3 or 4 flights on it before it flew away due to interference, likely from CB radios. I still have the transmitter due to its sentimental value, but as the previous poster advises, I would never consider using 27 mhz superregen gear in our current crowded rf environment.


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