Taylorcraft air speed

[Scott]

Re: Taylorcraft air speed

You cannot do an out and back course into a headwind and with a tailwind to determine TAS from the GS. You spend too much time in the headwind and it reduces the average GS to become a lot less than TAS.

Scott this is what you stated earlier, but too much time going slow is the reason we cannot. It is why I said the headwind effect is greater.

All good calculations Mark, unfortunately, as I said above, they have little bearing on the exercise. It simply does not matter how much time you spend on any one leg (assuming we're talking minutes not hours). All we need to to is establish the heading and straight and level flight, then read the GS off the GPS. Repeat for the inbound leg (or other two legs if you're doing two 120 degree turns). The mean of the GPS ground speeds recorded equals TAS.
S

[N96337]

Re: Taylorcraft air speed

Not germane to this conversation. But on the first flight of my '46 BC12-D after a total restoration and a C85 with a Sensenich 72x50 wood, my test pilot texted me this picture of the ASI

I planned on, and got 115 with my 85, running a 71/46 prop. That's on a short mount.... I could run circles around the long mount that a friend had.
John

[flyguy]

Re: Taylorcraft air speed

Don't think I have asked this before: Does anyone have their static port located about a foot inside the wing from the fuselage mount? The 12D85 I have is that way. Is that stock?

John, I have pretty much the same setup as you do, including the prop. Where is your static source?

Darryl

[Hank Jarrett]

Re: Taylorcraft air speed

My static port is the back side of the ASI. No claims about accuracy!

Hank

[LostnSpace]

Re: Taylorcraft air speed

On my '46 BC12-D, the static line is in the leading edge of the left wing, has the end crimped shut and several small holes, about .040 inch dia. around the tube just above the crimp, Forst Barber told me long ago that was how they came from the factory, gary

[N96337]

Re: Taylorcraft air speed

My static source is like Lost in Space described.

[flyguy]

Re: Taylorcraft air speed

From doing a lot of checks I have found that airspeed on mine has a increasing error with increasing airspeed. It is a new certified airspeed indicator and what I think is happening is that the pressure in the wing is getting lower as the airspeed goes up because of the openings in the trailing edge of the wing. What I see is the indication is exactly on with the GPS average at or near stall and is high by 9 MPH at the top end. (the old airspeed indicator had the same error, but was the wrong range for the Tcraft).

Some numbers are: Stall is 42 to 44. Indicated top is 117.5 (Avg). GPS true is 108.5 top (Avg). It is a -85 but I still cruise it at 2150 which will give me 88 MPH GPS average. These are at 2500 ft. One check at 7500 full throttle GPS averaged 110.

At 8500 and full throttle the RPMs went from 2450 to 2500 when I adjusted the mixture for peak RPM. At 11,200 ft full throttle 2350 the GPS average was 95 with 90 indicated.

I have to say that I don't pay much attention to my airspeed indicator until it gets down to 70 or lower. This plane has 800 tires and no strut fairings. Edit: Somewhere in my pile of notes it says 2300 cruise gives me 94 GPS. And at 2150 it burns 4.7 GPH.

DC

[PA1195]

Re: Taylorcraft air speed

Mine's (1941) in the left wing taped to something outboard of the wing tank. I leak tested the speedo line and sealed it until the needle stayed put under light pressure. The static is open to air pressure applied at the instrument fittings. All I know about the system.

Gary