Rubber Power Remote ControlInsane ideas seem to come naturally to Aeronutz.
NEW! Super Capacitors.
I have tested a 5 F super capacitor. It weighs 2.2g with 5mm long terminal. It is Dia 10mm x 20 mm long. I am not too sure what power and voltage these produce or what they can handle when charging. They are rated at 2.3v
I have been charging it with 800mA hr Ni CD AA size cells.
I figured they might need a bit of running in ? From new I charged it with one cell and discharged it using a KP00 without prop, then I did this again.
Then I did the same with two cells, twice but with a U80 prop fitted direct drive.
Then I charged the cap. from two cells and them three to get up to 3.65v ! This is well above the manufactures recommended 2.3v so if you do this it is at your won risk - they may blow up or catch fire?
At 3.65v I ran a KP00 with direct drive U80 to discharge it and repeat the charge and discharge again.Now I used some resistors and measure the following:
Charged to 3.65v and discharged with 8.5 Ohm resistor
Start = 312mA and 2.90v
15 seconds = 250mA and 2.40v
30 seconds = 193mA and 1.90v
45 seconds = 157mA and 1.60v
60 seconds = 113mA and lost interest by now.If you power a free flight 12g plane with a geared pager motor you would use about 200 to 250mA? The thrust would be about 8 to 10g? So your little plane would have a huge power to weight ratio!
If you wanted to use this cap for powering electronic control systems you would only use about 15mA for the Z Tron IR sytem with one 150 Ohm coil actuator (see lower down on thsi page)
If you wanted to fly R/C with Muscle Wire actuators you would use about 100mA for each rudder movement? so as a guess that would average out at about 60mA through a flight??
Most micro chips stop working at 2.7v so there does not seem much point going lower than that. I think the Albin 27 Mhz Rx will work from 1.25v?
Here is a test with a 47 Ohm resistor, 5 F cap charged to 3.65v.
Start = 68mA and 3.5v
15 seconds = 65mA and 3.0v
30 seconds = 60mA and 2.9v
45 seconds = 56mA and 2.7vSpeed controllers and proportional rudder systems pulse the power, this pulsing might be better for the cap? These tests are just directly connected to the cap.
Mark
12th Oct 2002New rubber power plane
Peter (indoor God) Frostick writes from Gordie land ...
Here's an early picture of my 15" clipped Piper-Cub used to test the system -total weight 12grams, and wing loading 1.3 oz --- this is a real "pussycat " to fly, and with more details now, looks very nice airborne. As you can see construction is mostly "Nutz" but with a bit of lightest balsa at key points --- The 0.8 gram flat radio is mounted between the U/C fairings.
"Eric Hook has come up with a super smooth non-flappy version of his famous indoor rubber powered single channel radio set -- 3.7 grms with 70Mah MiMH cell, or 2.8 with one Farad condenser. The great advantage is loads of actuator power, and range in or outdoors. The component count is a bit high, so not a job for everyone, but a lovely and super-reliable little outfit. It runs for 60 minutes on a single charge of the NiMH cell!!!
Peach Blush. Like a Tango but with longer nose and longer wings. Powered by a 70 to 85 thou. rubber depending on the hall size, with a Ikara white plastic prop, the middle of the three sizes available. It has bang bang rudder or proportional rudder control, the power for the control system is supplied from a one Farad capacitor. Wind up the motor, charge the cap. and away you go for 60 seconds - over there, back over here again, in that corner, over Bernard's head, left, right and straight ahead. If you get too high leave it in a turn to burn up some power, one the way back to your table go in a straight line as it's much more efficient to fly with the wings horizontal. The infra red receiver, sensor and capacitor are right up the front end to balance the weight of the long rubber motor and actuator at the back. Ideal for small school and village halls.
Uses a 150 Ohm coil and this one has the smaller magnet but you could use the larger magnet if you flew Co2 power.
Next up is a scale looking plane and maybe elevator too as we do have a huge power to weight ratio, SAAB Viggen, F18?
Bang Bang or proportional Rx with one sensor and 1 F cap. £13 2 grams
150 Ohm coil with either magnet £5 or £7.50 1g
Prop. £0.80
Rubber £1.50 for 30'
Plane, eh? £0.10
CapRx ActuatorWhy Peter Frostick put Eric Hook’s R/C LacyM10 and flew silently around sports halls using rubber power is a mystery to me. But with hindsight it is a very good idea. The name of the game in indoor flying is weight reduction and Peter had got rid of an electric motor, gearbox, heavy plastic prop and three or four 50mA NiCd cells all in one go. I had the great pleasure in seeing his silent flier visit all four corners of our large sports hall in Oadby before power gliding back to his outstretched hand, to be wound up ready for another spin.
I have had some watch batteries for about three years when Simon and I had hit the stone wall of the WES Technik servo’s 2.7v minimum voltage and had thought of ways around this.
I had played with them lighting up our mini LED’s and I can remember measuring the current at about 17mA for one LED.
Only a two weeks earlier I had measured the current used by our 200 Ohm coil and infra red receiver and that was using about 15mA!I weighed a Tango with it’s rubber and prop and it came out at 7g. The IR Rx without power transistor but including 200 Ohm coil and one magnet weighed in at 3.5g. So a flying weight of about 10g was a realistic target. I calculated the Tango was flying at 1 oz. Sq Ft and worked back to predict the size of a Super Tango at 9g. and about 14” span, I copied the planes and was horrified at such a huge machine !! It flies nice and slow though and you can just see the coil and sensor, better picture later !
Turing to our old favourite the trusty Jigglet I figured if I double the wing area by making it a biplane I could add another 3.5g to its usual 4g and all should be well. We now have our 200 Ohm coils across the fuselage with the magnet inside inline with the fuselage, so making the fuselage a little wider and sticking the coil on the end of it would look quite neat. I made the nose and rear end a little longer and glued the lot together. The coil turns out to be quiet heavy so I have located the two coin cells right up the front above the rubber motor.
I have used two CR1220 coin cells which are rated at 3v each as they are Lithium but cannot be recharged. They cost about £1.50 each and are readily available from high street shops or Farnells. You can also buy slightly larger ones for the same cost. Under a 15mA load they drop their combined voltage to about 4v. With the magnet inside the coil (BIRD style) the rudder has plenty of power at 15mA and I will try dropping that down to about 10mA by adding a SM resistor.
Dr Chris has found some rechargeable Lithium coin cells while Mike Watter’s used four smaller rechargeable Ni Cd ones in his Co2 powered IR machine.
I will try the IR Rubber Jigglet Bipe on Saturday 30th Dec 2000 at our Indoor Expo and hopefully it will do sixty second hops as a minimum as Jigglets have been clocked at over two minutes.
The total cost for the plane is about £18, I might make a Super Tango as well ....
Dec 31st 2000. Following our Indoor Fun Fly last night - the Super Tango weighs 9g with 85 thou rubber and two CR1620 cells while the biplane Jigglet weighs 8g with two CR1220 cells. The Tango flies at the same speed as the F/F version and responds well to rudder but did not climb and had an odd sit in the air ?!?! The Bipe Jigglet flies nice and slow too but had bent wings and would not turn, needed lots of nose weight to balance which was not helpful, but this can be corrected by moving the Rx and two sensors forwards. The Super Tango has just one sensor facing outwards and about 30 degrees downwards.
The 200 Ohm coil and magnet are making the plane tail heavy so you need the cells right up the front which is obviously in the way of the rubber motor. I think the best way to switch on/off the control system is to have the two cells help together with an ortho band and trap the wire connections with chunks of balsa. Solder all the joints and then slide a piece of very thin ply or balsa between the cells to switch the system off. Wire it all up with 38g enamelled wire from Maplins, the stuff that melts the enamel easily. Both planes use Ikara plastic props, the Super Tango uses the larger size (same as the Butterfly). Both machines had 200 Ohm coils and just one Maplins Dia 3mm x 2mm magnet inside the coil.Jan 18th 2001
Super Tango now has Panasonic pencil shaped cells (flitehook) in it on the inside right up at the nose, Rx is now inside too. Watch cells would be tricky to fit in the nose area, Looking into using a capacitor so we don't need a switch at all !Jan 28th 2001
Mark has tested the 2.5v Gold Cap 1.0F capacitor: charged from a 3.78v battery for about 30 seconds.
200 Ohm resistor, constant load.
15 seconds 16mA 3.25v
30 seconds 15mA 3.08v
45 seconds 14mA 2.91v
60 seconds 13mA 2.75v
So we should be OK to power a rubber powered plane with IR control system running from a 1F cap.
The Cap will be running beyond it's manufactured capability so make sure the ends are not pointing at anyone should
it go bang !
Mark also tested the IRRXFA with a 3.78v supply and the following resistors in place of a coil.
150 Ohms = 12 and 15mA
200 Ohms = 13 and 10mA
100 Ohms = 16 and 13mA
So you can use a lighter coil with more current for rubber powered or single cell machines at lower voltages.
I have tested the proportional IRRXFA and 200 Ohm coil powered by a 1F cap and found that the Rx does not work below 3.4v? I tried the bang bang IR Rx and it worked down to 2.5v ! (both Rx should die at at 2.7v) I will try and find out what is wrong. We might be able to use the new super capacitors, we are hoping for a samples soon, other than that I might bang bang Rx's for the rubber powered planes, which fly real slow anyway4th Feb. 2001
Mark tested the Z Tron "Bang bang" Rx with 150 Ohm coil and 1 F cap and flipping the rudder back an forwards constantly it runs for 4 minutes ! The first sixty seconds being pretty powerful - looks good2nd March 2001
Mark now has 10 Panasonic Gold Cap 1F capacitors for powering the AC3 (bang bang) infra red receiver, they are £3.00. The caps. weigh 1g and are Dia 8mm x 22mm long plus a bit for the terminal wires. To charge the cap up you use one cell for 10 seconds the two cells for another 10 seconds and then a three cells for 15 seconds. Then you disconnect the battery and the Rx works for about four minutes, the first 60 seconds the rudder is quiet powerful. Use a 150 Ohm coil and a Dia 3 x 2mm neodium magnet. This system with one sensor have been used on Mark's new 13" span Tango with an Ikara plastic prop and 80 thou. rubber, first flight will be at Cambridge on the 18th March .
The bang bang Rx is use instead of the proportional one as it seems to give more power and we don't really need it to be proportional for rubber power anyway. We have found that the latest sensors do not work on the capacitor so use an older one, with the single purple stripe on the back. Total flying weight of the system is about 3g. An AC3 Rx with one "old" sensor is £10, the 150 Ohm coil with Dia 3mm x 2mm neodium magnet is £7.50When you fly "Bang Bang" rudder using the Z Tron system you need the AC3 reciever. If you have a Z Tron transmitter you need to adjust the little DIP switches inside of the Tx. This is not difficult, just remove the four screws on the rear of the Tx and remove the back cover. The DIP switches are on the cicuit board, a black block with little white levers on the side. Gently press switch marked 2 down. Job done. If you want to use proportional control again the number two switch needs moving back up again.
If you like you can add a new switch on the outside of the Tx case so you dont have to keep taking the back off.
To do this all you do is take two wires from the new on/off switch terminals and solder them to switch two's connections on the underside of the circuit board. Now leave switch two in the up position and use the new switch.Nice little radio control, stick and tissue, rubber power bipe here
