Scale Wendell Hostetler 30% Piper Cherokee Glass Fuselage Build.
- Thread starter TonyHallo
- Start date
TonyHallo
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The sensor hub is completed. The right pins are Sport serial and the six temperature sensors. The accuracy is 5 f from pin to pin. Close enough for monitoring engine temps. The left side top pin is 0 to 10 volt analog measurement, second pin down is the tach input, bottom is 5 volt in and ground, blue pin is the 3.3 reference voltage for future use, two spare pins. All tested and ready to go.
Snoopy1
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How is the temperature done or should say measured. Is some sort of thermistor used ?
dhal22
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TonyHallo
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Snoop,
A voltage divider circuit using a 100K thermistor in series with a 100K resistor supplied with 3.3 volts. The code uses the Stein-Hart equation to calculate the temperature based of the voltage measured at the junction of the thermistor and resistor. Found the code online and modified it for my use.
The analog voltage measurement is done in the same manner only using 3 to 1 voltage divider circuit.
RPM is measured using a library found online called Tachometer, I think I just copied the code from example and works. Put in a 60hz signal in and the rpm reads 3598, close enough for me.
I'm kinda getting the Arduino, looking for an air flow sensor to use with electronic carb. Also thinking about a throttle position sensor rather than using the throttle stick position as an input.
A voltage divider circuit using a 100K thermistor in series with a 100K resistor supplied with 3.3 volts. The code uses the Stein-Hart equation to calculate the temperature based of the voltage measured at the junction of the thermistor and resistor. Found the code online and modified it for my use.
The analog voltage measurement is done in the same manner only using 3 to 1 voltage divider circuit.
RPM is measured using a library found online called Tachometer, I think I just copied the code from example and works. Put in a 60hz signal in and the rpm reads 3598, close enough for me.
I'm kinda getting the Arduino, looking for an air flow sensor to use with electronic carb. Also thinking about a throttle position sensor rather than using the throttle stick position as an input.
TonyHallo
640cc Uber Pimp
Yesterday's update;
Block sanded the fuselage with 220 wet and filled the low spots, these were sanded as well, ready for primer today.
Started looking at the starter conversion on Saito. The Ephil engine and the Saito are both 10 mm shafts. The prop hub on the Saito is mounted to the shaft with a tapered collet while the Ephil clutch hub is a straight 10 MM bore with a key slot, The clutch hub has the magnet installed for the ignition however it is too small for the Saito pickup. Measured the taper of the collet and found it to be .113 mm/mm. Found this a little odd, was expecting a whole number like 1 to 8. Set up the clutch hub and cut off the aluminum ignition magnet ring. Starting setting up compound slide but decided it has too much slop and needs reworked.
The slide is attached to the degree dial with 3 - 5 mm screws, the screws are phillips head with what I assume to be a #3 JIC phillips, it's all but impossible to tighten these screws up. A trip to Ace hardware yielded 3 - 5 mm socket head screws, took a little grinding to make the screws work but the screws are now tighten with a 4 mm allen key with an 8" cheater bar, tight now.
Today I need to come with a way to mount a dial indicator on the slide feed to set up to the exact measured taper. When I looked at the Saito parts breakdown, the collet and hub are sold as a set, possibly lapped during manufacture.
The collet brought back some old memories of the power plant, can't tell how many vertical turbine pumps we had. There were well over thirty different model pumps.
Block sanded the fuselage with 220 wet and filled the low spots, these were sanded as well, ready for primer today.
Started looking at the starter conversion on Saito. The Ephil engine and the Saito are both 10 mm shafts. The prop hub on the Saito is mounted to the shaft with a tapered collet while the Ephil clutch hub is a straight 10 MM bore with a key slot, The clutch hub has the magnet installed for the ignition however it is too small for the Saito pickup. Measured the taper of the collet and found it to be .113 mm/mm. Found this a little odd, was expecting a whole number like 1 to 8. Set up the clutch hub and cut off the aluminum ignition magnet ring. Starting setting up compound slide but decided it has too much slop and needs reworked.
The slide is attached to the degree dial with 3 - 5 mm screws, the screws are phillips head with what I assume to be a #3 JIC phillips, it's all but impossible to tighten these screws up. A trip to Ace hardware yielded 3 - 5 mm socket head screws, took a little grinding to make the screws work but the screws are now tighten with a 4 mm allen key with an 8" cheater bar, tight now.
Today I need to come with a way to mount a dial indicator on the slide feed to set up to the exact measured taper. When I looked at the Saito parts breakdown, the collet and hub are sold as a set, possibly lapped during manufacture.
The collet brought back some old memories of the power plant, can't tell how many vertical turbine pumps we had. There were well over thirty different model pumps.
Snoopy1
640cc Uber Pimp
Remember using thermistors at work but all we did was use a known thermistor and set the voltmeter to Ohms and reading you got was the temperature, neat device but have never seen them on the open market. Should have asked the instrumentation department at the time for some info
Snoopy1
640cc Uber Pimp
A lot of work for a starter but if you need the weight nice thing to have. A lot more fun than dead weight.
TonyHallo
640cc Uber Pimp
I bought the thermistors on Amazon, $2 each, they are used in a 3d printing machine.
Yes but I'm loving it!
TonyHallo
640cc Uber Pimp
Drilled and tapped a 1/4"-20 hole in the cross slide to mount the dial indicator for the longitudinal travel the cross feed was measured with the dial indicator set up in the QCTP holder. Was luckly to get .069" feed and .611" travel.
The clutch hus bored to the taper and the collet fits in nice, no rocking. Blue checked the fit and have contact across the bore. I was planning to lap the bore but have no need to do so.
Need to put more threads on the shaft for the retaining nut.
Put the second coat of primer on the fuselage and calling it quits until it's time to paint, I'm sure it will get a few dings over the winter while completing the work.
The clutch hus bored to the taper and the collet fits in nice, no rocking. Blue checked the fit and have contact across the bore. I was planning to lap the bore but have no need to do so.
Need to put more threads on the shaft for the retaining nut.
Put the second coat of primer on the fuselage and calling it quits until it's time to paint, I'm sure it will get a few dings over the winter while completing the work.