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Torque Meter for very light helicopters - Printable Version

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Torque Meter for very light helicopters - bryancobb - 10-07-2012


Everyone, including me, has been trying to come-up with a super-simple TORQUE METER for Helicycle, Mosquito, Mini-500, etc.

Some of the logic we have discussed is measuring twist in the mast...stretch in the belts...deflection of the transmission case...and even miniaturizing the HUEY "2-washers with steel balls" torque meter.

Another thread got me thinking about it this morning.

WELL...I'VE GOT I!!! Cost? Less than $20. Weight? Less than 1/2 pound.

Background: I learned to fly helicopters in Army Primary, in the TH-55 (269).
The manifold pressure gauge was color coded and it had nothing to do with limitations. The green / yellow / red arcs corresponded with a 1" wide color strip on 1 antitorque pedal, and a pointer on the other pedal. As pedal position changed (torque varied) the pointer gave an indication on the color strip.

This was for students that didn't have a good feel. They could look at the manifold pressure color arcs and PUT THE PEDALS in the same color zone.
This was a "Forest Gump" way of teaching students to apply the right amount of pedal for the amount of torque being used.

Now see the next post for a P E R F E C T torque gauge for little helicopters.
Gimme about 30 minutes to do an AutoCAD sketch.


RE: Torque Meter for very light helicopters - bryancobb - 10-07-2012

If you have flown R/C airplanes, you will be very familiar with NyRod by DU-Bro. I once used this stuff for a elevator trim indicator on an ultralight had. It works great.

By using pedal position as the input for a TORQUE METER, you are automatically correcting for changing weight as fuel burns, changes in density altitude, and decreased power requirements due to wind.

The bright yellow, 1/8 diameter inner NyRod is highly visible through a 3/16" wide slot that is cut in the panel.




RE: Torque Meter for very light helicopters - bryancobb - 10-07-2012

More in-depth discussion here...

http://www.rotaryforum.com/forum/show...


RE: Torque Meter for very light helicopters - UH-60Pilot - 10-09-2012

That is brilliantly simple! Very cool.


RE: Torque Meter for very light helicopters - rsm - 10-09-2012

I like it. Simple yet effective


RE: Torque Meter for very light helicopters - bryancobb - 10-09-2012

UH-60Pilot - 10/9/2012 6:55 AM

That is brilliantly simple! Very cool.

Dang! Mark. THAT made me smile! For someone that's seen and experienced what you have, that complement FROM YOU is appreciated.



RE: Torque Meter for very light helicopters - UH-60Pilot - 10-09-2012

Yeah Bryan! I was talking to dwight on the phone about exactly this yesteray and then I saw that you had posted this so I emailed him the link last night. This demonstrates a real understanding of what actually needs to be measured. I guess the instalation goes in first and then all that has to be done is to accurately mark the indicator slot on the panel which is probably the hard part. I guess the best way to do it would be to tape a ruler along the slot and then go out and fly for measurements. Calm conditions would be a must for accuracy. First, enter a hovering auto (no airspeed) from very high and look at the measurement required to hold the nose straight at 100% main rotor rpm with the clutch disengaged (probably full right pedal). Second enter a hover at a known weight and measure against the ruler. Third, start adding weight externally until rotor droop occurrs or until there is no longer enough left pedal to maintain heading and make the final measurement. Lastly, set the low and high pedal settings and then measure the angle of incidence of the tail rotor blades. I think that if this was done once it could be duplicated on every helicopter (of the same power plant) with pretty good accuracy. Does that make sense?


RE: Torque Meter for very light helicopters - bryancobb - 10-09-2012

UH-60Pilot - 10/9/2012 9:19 PM

Yeah Bryan! I was talking to dwight on the phone about exactly this yesteray and then I saw that you had posted this so I emailed him the link last night. This demonstrates a real understanding of what actually needs to be measured. I guess the instalation goes in first and then all that has to be done is to accurately mark the indicator slot on the panel which is probably the hard part. I guess the best way to do it would be to tape a ruler along the slot and then go out and fly for measurements. Calm conditions would be a must for accuracy. First, enter a hovering auto (no airspeed) from very high and look at the measurement required to hold the nose straight at 100% main rotor rpm with the clutch disengaged (probably full right pedal). Second enter a hover at a known weight and measure against the ruler. Third, start adding weight externally until rotor droop occurrs or until there is no longer enough left pedal to maintain heading and make the final measurement. Lastly, set the low and high pedal settings and then measure the angle of incidence of the tail rotor blades. I think that if this was done once it could be duplicated on every helicopter (of the same power plant) with pretty good accuracy. Does that make sense?

Sure Does Mark! This would give the Mosquito pilot another outlook on life... Now for $10 and a day of your time, you could have a torque indicator / power instrument.
I tried to present a Brantly-Style 100% simple fail-safe and accurate low fuel warning system, a year or so ago but no-one paid any attention.
******************************************************************************************************************************
Posted 5/27/2011 12:30 PM
Subject: 1/2 Pound Low Fuel Warning System

Here is a cartoon of the Brantly's Low Fuel Warning System. This system is "Butt-Simple" and a Mosquito could be equipped this way, very easily. It is reliable, positively calibrated, and almost 100% reliable.
The positive pressure inside the MZ-202 shroud at operating RPM is more than adequate to make the system operate.

On my helicopter, TEE "B" was at the 2 gallon level or about 11 minutes flight time. At the 18 minute level, the red light would come on occasionally as I maneuvered normally. At the 14 minute level, the light would be illuminated about 50% of the time unless it was dead calm and I was straight and level. As I approached 11 minutes the ratio of time ON vs. OFF would increase until at 2 gallons the light would remain on constantly.



RE: Torque Meter for very light helicopters - tomo - 10-09-2012

Bryan, do you have a part number for the switch?

Tom


RE: Torque Meter for very light helicopters - bryancobb - 10-09-2012

My Brantly used THIS one but Dwyer has several for 1/5 that price that would probably work.
You would need to know how much pressure the cooling shroud has at full RPM and the get a Dwyer switch with the equivalent WATER COLUMN WC range.