737 T/Q

[johncor]

Hi there,am building a t/q but have no idea how to connect the potetiometer to the throttle levers because the lever travel on the boeing t/q is only 60 degrees and all I can find for sale are pots with around 300 degrees of travel which when connected would give me only 1/5 of the power setting when the throttle levers are at full forward position.how do builders get around this problem? any help please ,john

[Jan737]

Hi Johncor,

We using gears, a big one (70 teeth) on the lever and a small one(20 teeth) on the pot.
That will give you a good ratio.

Best regards

Jan Geurtsen

[Goldmember]

For gears, get an old laser printer and disassemble it. Loads of neat parts to use for tq or other moving things

[AirFan]

Hi John,



as already described you need to use gears.



To use the complete range you need to find a gear with the correct ratio. Here an example:

Lets assume you have a 280 deg pot and 60 deg lever travel.

the ratio would be 60/280 = 0.214. That is your target ratio. Lets assume you want to use a gear at the lever with 50 teeth.

Then you need a smaller gear for the pot (50t*0.214=10.7t). Since you wont find a gear with 10.7 teeth you could use one with 10 but that would exceed the travel of your pot since

your actual ratio would be 10/50=0.2. That means your pot would use 300 deg (60/0.2) for a lever travel of 60 deg. Thats to much since you have only 280 deg.

So you have to use a bigger gear for the pot. Lets try 12 teeth. 12/50=0.24 --> Now your pot would use 250 deg (60/0.24) for a lever travel of 60 deg. Which is close to your target.

I hope that helps you abit.



keep in mind that the travel of the pot has a tolerance. You should find it in the datasheet. For the max travel of the pot you should subtract the tolerance from the max travel value.



Cheers,

Rob

[johncor]

Thank's guys for the help,since i'm building the tq from scratch it would not make such a difference if the lever travel is a couple of degrees either side of 60 degrees.thank's again, john