Old Escapement Radio System

Hmmm..well, if the transmitter has a tube in it, it would require a 1

1/2 volt battery for the filaments and most likely one 67 1/2 volt battery, or possibly 2 of them in series for the power. On the other hand, if it does NOT have a tube in it, it would most likely require a 9 volt battery for the transistor circuitry. The receiver, assuming it has a tube and transistors in it, would then require a 1 1/2 volt battery for the filament and usually a 22 1/2 volt battery for the power. Escapements usually run on 3 volts and that power would be separate, controlled most likely by a relay in the receiver. However...if there is some who knows exactly what this unit requires..please sign in with the info....I am just going on what I remember. Frank Schwartz

The transmitter does have two tubes. No tubes in the receiver. Earl

Look at the tube types and I'll tell you their filament requirements. If they're 2 volt tubes then a 6V filament battery with a rheostat to adjust current would be more or less standard -- 1.5V tubes would be connected directly to a dry cell.

One Tx tube is "3A4" Tung-Sol 3226178-1 Other is "1L4" Tung-Sol 3226112-1 (guessing at the last 3 digits, almost erased) Earl

3A4 is a 'power' pentode, good for 2 watts at 10MHz, certainly at least 500mW at 27MHz. Max plate voltage 150V. Has a 3V, center-tapped filament that will go right onto a 1.5V dry cell.

1L4 is a regular ol' pentode, max 90V on the plate, 1.5V filament.

The filaments almost certainly go to a single dry cell.

Frank's comment about a 67.5V plate supply is almost certainly correct (certainly he has more direct experience than me!).

Or a 90v single.

>

As much fun as it would be to fly RO again with tubes, let me suggest that if the thing will operate, you shouldn't. My logic is that it is valuable and will become more so if it is in operable condition.

A crash was common back when we were using those things and the air was a heck of a lot cleaner then than now. There are all sorts of frequencies out there and there is wide-band splattering everywhere.

I would encourage you to clean it up and enjoy it on a shelf.

If you would like to fly RO again, there are ways to rig current, clean, legal, xmitters and transmitters.

I would enjoy rigging a cheap receiver and servo in a common plastic box to make me a brick. This would be proportional RO. Anything that would carry the rig you are talking about would easily handle a servo arm pushing a microswitch and a coil/magnet, bang-bang control system if that is what you want...and that would satisfy the tinkering urges without risking nice old gear.

It would be easy to rig a "ratcheting" binary stage to the switch so you would have "tap" for right and the next "tap" would give you left and so on. This would safely mime non-neutralizing escapements.

All the things that frustrated us and cost us money back then, got in the way of some really neat RO aerobatics.

Ken

Can someone explain in layman's terms what a tube does, and how? I'm just curious, but if it's a long explanation and you don't feel like typing, don't!

Good flying, desmobob

Tubes were what we used for amplifying and oscillating before there were transistors (and for some time afterward). In the most common application, a small voltage applied to the grid of a tube controls a larger voltage applied to the plate.

Tube theory 001 (for tube theory 101 you'll need to search the web).

Cathode gets hot, electrons boil off.

When the plate is more positive than the cathode, electrons flow to plate; when the plate is more negative than the cathode, electrons stay close to the cathode. If that's all there is you have a diode (never mind the heater connections).

Heater? Oh yea -- to get the cathode hot you either use the filament or you put a heater behind a cathode. So a vacuum tube diode has at least three (two filament, plate), maybe four (two heater, cathode, plate) connections. That's right. Di = 2, so you need three or four wires. Who said times have changed?

If you put a grid between the cathode and plate, and make the grid negative, the cathode thinks the plate is more negative than it is. With cathode-grid-plate you can control the current between cathode and plate with the grid. Furthermore you can get _big_ changes in plate current for _little_ changes in grid voltage. This is a Good Thing.

A tube with cathode, grid and plate is called a Triode. In the nomenclature of vacuum tubes a triode will come with four or five contacts.

You can get better performance in many ways by adding one or two more grids. With three grids (the 'control' grid from a triode, a 'screen' grid and a 'suppressor' grid) you get a pentode (pent = 5, which is why you need six or seven wires -- clear?). These have lots of advantages over triodes, mostly because the screen grid electrically isolates the plate from the cathode, and the suppressor grid fixes a problem with electrons bouncing off the plate and getting swept up by the screen grid.

Compared to transistors vacuum tubes are big, expensive, slow and energy inefficient (transistors don't need heaters). The very first transistors were fragile, more expensive and slower than vacuum tubes, yet they were so incredibly small (for the time) and energy efficient that they rapidly started making inroads on vacuum tubes.

While there are still some areas of technology where vacuum tubes are holding their own (CRTs are vacuum tubes, and some microwave transmitting equipment is best implemented with vacuum tubes) solid-state electronics have eaten the vacuum tubes' lunch, then made themselves dinner and desert and have eaten that, too.

I am pretty sure the transmitter used a Flashlight battery C or D for the filament and a pair of 67.5 V batteries in series for the B+

I don't know what the receiver used.

Another good reason to not fly with the old receiver is that the old recievers that I am familiar with were all super-regenerative type receivers. Super-regen recievers gave good sensitivity (for their time) but had very poor selectivity. They were marginal in the 60's when there was a lot less RF stuff running around. These days I think it would be a disaster.

Good Luck, Bob

Some of the modern micro R/C systems use magnetic actuators instead of servos. They provide a "bang-bang" type action (full left or right rudder and neutral). This mimics R/O type action of the escapements fairly close.

When Ace R/C popularised the Adams actuator for R/O, we now had proportional rudder with the wagging tail that was a vast improvement over escapements.

I don't know why one would want to go backwards. To fly R/O stunt using only rudder and motor control would be practical with a modern R/C radio system and modern engines/motors. There are many R/O plans available for scratch building.

This would mimic the essence of early radio flying. Few know how to do it effectively, we did it all the time.

It is amasing how much one could do with R/O. Adding throttle control just expanded it so much more.

-- HPT

I came into the hobby at the very end of the life of the ACE R/O system. I think the most fun I ever had was with a model that was essentially a slightly beefed-up P-30 rubber model with a reed valve 020 in the nose, and adjusted for a floating glide. With careful rudder control you could barrel roll indefinitely without losing altitude -- the only limit was when you ran out of field or eyesight.

Boy was that a fun plane. The radio stopped working one day right after the engine cut out, and it serenely glided out of sight, never to be seen again.

P.S. I haven't used the magnetic actuator systems, but I understand that they can be somewhat proportional with careful magnet placement.

So why not just buy a cheap two-channel proportional rig for $50 and pretend it is single channel? Same effect, better reliability and infinitely safer.

Ed Cregger

I "learned to fly R/C" with a Testor's Skyhawk. Anyone remember those RTF models?

To be honest with everyone, it took two of them. The first one I was nearly finished the first flight with the Testor's .049 still screaming when I jammed the stick the wrong way for a turn and spiraled it right into the concrete.

The wife and I hopped in the car and went back and bought a second one. I was okay after that and learned to loop and roll my single channel pulse proportional model with no throttle control. When I bought my first multi rig, I taught myself how to fly it also, with no problems. The Skyhawk had trained me well.

Ed Cregger

I have a 1937 QST (from the Amateur Radio Relay League) which features an article on RC. It used a two- or three-tube superregenerative on 5 meters (they changed the bands after WWII). The aircraft is a glider with what looks like a 10 or 12 foot wingspan. It looks like they chucked it from the top of a big hill then drove down to retrieve it. Control was by relay then escapement, with a hand made escapement, no less.

Aesthetically it's a disaster -- the styling is your basic blob with wings -- but hey, it was 1937, and it flew.

I've considered building a replica of it, but sneaking a mixer and IF filter before the superregen to make it survive the current RF environment, and using octal base tubes (the original type 30, 32 and

1F4 tubes are _way_ expensive these days). I suspect I'll still be thinking about it on my deathbed, but it's fun when I'm away from my workbench.

I'd _love_ to find an article on the same craft in a modeling magazine.

Ed, the first r/c model I launched was a Fox-powered something with tubes and push for turn. You had to remember which direction you turned last because the next time it would be the other way.

I only launched them, I couldn't really say I flew them. I might get a minute or two of near controlled flight and then something froward would happen and we would go look for the model. I was not flying for a hobby as much as I was hiking.

I finally scratch built a high-wing V-tail with .02 on a pylon at the nose.

Now I had moved up to a self-neutralizing escapement. I had more fun with that thing. I still have the wing. The others on the field were moving into three-channel simultaneous (remember that term) and proportional...and I was still winding up a rubber band before each flight. The more the made fun of me, the more I flew.

My little RO outlasted many of their models.

Then I moved up to Rand two-channel pulse actuators, then Rand three-channel pulse.

Every flight was an adventure.

Ken

By the way...they were invented by a British guy, Dr. Lee DeForest, and they were called "valves" there because that is exactly how they behaved. They would control how many electrons flowed through the wires just like a valve controlling water going through a pipe.

In the early transistor days, I was working on a nuclear test aircraft. It carried a reactor for a variable radiation source. This was in 1955. Because of the radiation environment, we couldn't even use simple hard diodes. We had to use all vacuum tubes and this included small vacuum tubes that were just diodes.

Ken, who is older than some dirt.

From desmobob:

There've been some excellent replies here to your question. The Brits call a tube a "valve" for obvious reasons. If you're familiar with a transistor, think of it as an analog of a triode tube. A transistor has 3 elements which correspond to elements in a tube =96 emitter('cathode'), collector('plate'), and base('control grid'). A transistor can operate at far lower supply voltage than a tube requires, and doesn't need a hot cathode either. The analogy breaks down a bit in that a transistor has a low input impedance (i.e., it loads the signal source down). Whereas a tube has a very high input impedance (it puts no load on the signal source). Enter the FET (or field effect transistor), which has a high input impedance just like a tube, and puts no load on the signal source. Thus the FET is a true triode analog, with the corresponding elements designated =96 Source('cathode'), drain ('plate'), and gate('control grid').

From the OP (Earl Partridge):

Small point, but it's actually termed a 'B' battery. From the earliest days of tube radio, the filament supply was termed the 'A' battery, and the plate supply the 'B' battery. The term 'B plus' (or B+) was thus adopted signifying the plate supply in all tube equipment, whether battery operated or AC line-operated. A third battery called the 'C' battery was used in some early sets. Its sole function was to supply a few volts to bias the tube grids. 'Bias' refers to a small, fixed negative voltage which sets the tube's 'idle current' under no-signal conditions. But no current is drawn from the C battery, so it lasts virtually for its shelf life.

Bill(oc)