Trustline offest in TS?


Platinum Member
I think is looking to see if indeed the twinstar is consider CTL.

Tim In the manual I send I have cg claculated and hang. I beleived that in the hosfra document(sorry if I mispelled) there is the definition of where the trust should be to be consider CTL.

I would sit a person in the front seat take a picture and drw a line from the center of the engine fowrad then see hwre I cut the pilot and then measure how for is our belly buttom from the line.



Platinum Member
Data: "Main axle height above floor"

Ahh.. my axels measured where they meet the wheel or frame or?
This question refers to your gyro pivot point, Tim. i.e. the center of your main wheels.


Vert CG

And I get thrustline offset from??

Do I measure the height of the probeller hub and subtract from the intersection of Vert CG and Horz CG?
The thrustline offset is the vertical distance between the location of the vertical CG and the imaginary extension of the prop thrust line - i.e. the line extending from the center of your prop and normal to the prop plane.

For example, if your horz. CG is 6 inches in front of the mast and the vertical CG is 40" above the floor, find the distance between that point and the imaginary prop thrust line.



Platinum Member
First Try a no-go

First Try a no-go

Went to the hangar today with scales, lazer levels and measuring tapes.

However, the proceedure outlined in the spreadsheet will not work for the Twinstarr.

Regular bathroom scales maxout at 300 lbs and even with boards under the tyres the scales stuck at 275.

I will have to find, borrow or rent scales that can read up to 400 or 500lbs to do this.


Any suggestions on scale sources?


Platinum Member
Scrap Iron buyers

Scrap Iron buyers

You can go to a scrap Iron deal and they have drive on scales that are very accurate. pull your gyro on the scales and they will give you a digital read out. Also state police weight stations. hey, its your tax money, might as well get something for it . They would probably like to see a gyro on the scales. Take a picture and give them one.


Platinum Member
Thanks guys!

Dean I followed your lead and found some 550lb scales on ebay for a little over $50 each (need 2 for the job).

So it looks like it might cost me $110 bucks to get my Thrust Line measured.

Anyone want to buy 2 bathroom scales that read up 550lbs each? Only used once!


Good thinking. Those scales could give me an all-up weight but if I could trailer by gyro I could do a double-hang test.


Gyro Blacksheep
Shoot Tim... if ya get them off ebay; use them once and resell them on ebay. Who knows, you may make money off the deal :)
I made 20 bucks off a graphics card that wouldn't work in my PC... almost bought 10 more but then thought about the idiot that started the pet rock and changed my mind :)
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