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Trutrak T&B

szicree

Well Known Member
I hope this isn't a stupid question and that someone will know the answer. Does the horizon on the Trutrak turn and bank instrument actually give bank info, or is it indicating yawing motion like a turn indicator? Thanks in advance.

Steve Zicree
 
From their site...

"Pictorial Turn & Bank
In contrast to the turn coordinator, the Pictorial
Turn & Bank provides a display that agrees with
the artificial horizon, and likewise the real horizon."

http://www.trutrakflightsystems.com/ttfsinstruments.html

With the TS in the bottom it would give yaw information as well. Those TruTrak guys have some really cool instruments.

Rat
 
I think they mean that the horizon indicator moves correctly as opposed to the reverse direction on a traditional turn indicator. My question is still whether the internal gyro is sensing bank or yaw.

Steve Zicree
 
Trutrak Turn & Bank

Hi Steve,
Yes it will give you bank information. It has a couple of marks on each side of center; these are the constant rate of turn markings.
The ADI unit does give bank also, but with more detail that the Turn and bank only. The ADI displays bank information in 10 degrees increments up to 30 degrees.
Alex D
Trutrak Rep
www.aviationtechproducts.com

Any question let me know
 
Now I'm more confused than before. Traditional turn indicators sense actual rate of turn around the vertical axis. They do not sense bank angle. What exactly is the Trutrak T&B sensing? I can see that the instrument INDICATES bank, but is that really what it's measuring or is it deducing bank angle based on yaw data. As a similar example, the Trutrak ADI INDICATES pitch, but actually deduces pitch from vertical speed. I guess what I'm getting at is would the T&B indicate a roll if the plane was banked but not actually turning?

Steve Zicree
 
Last edited:
szicree said:
Now I'm more confused than before. Traditional turn indicators sense actual rate of turn around the vertical axis. They do not sense bank angle. What exactly is the Trutrak T&B sensing? I can see that the instrument INDICATES bank, but is that really what it's measuring or is it deducing bank angle based on yaw data. As a similar example, the Trutrak ADI INDICATES pitch, but actually deduces pitch from vertical speed. I guess what I'm getting at is would the T&B indicate a roll if the plane was banked but not actually turning?

Steve Zicree

Well, that was certainly an aviation "lesson" that I wasn't aware of.

I had a spare turn coordinator sitting in the box, that I replaced with an A/P. Still had the wiring in place and connected it up, seeing how I could freely roll it left and right, and yaw motions around the vertical axis.

Just as you've stated, it does not sense bank angles expect for a bit of yaw I might be inducing when I move it by hand. But it quickly neutralizes even in a steep bank angle.

Obviously, I havn't been paying attention to a turn coordinator during knife edge flight! :) , But what happens if cross-controlled forces are in effect, as with a knife edge?

L.Adamson
 
What T&B's sense

A "normal" gyro-based turn and bank instrument sense yaw rate. It does not sense bank angle. If you bank to the right, but give enough left rudder to maintain a constant heading, a traditional turn-and-bank will indicate zero turn rate.

A "normal" gyro-based turn coordinator indicates a combination of roll rate and yaw rate, mostly the latter. The idea is to help you fly partial panel by giving you a little lead indication of a turn that is commencing. As you roll into a right turn (intentionally or otherwise) it that roll rate causes it to indicate a right bank. Note that after the roll rate stops, it indicates just yaw rate. If you gave a lot of right rudder, and enough left aileron to keep the wings level, the airplane would turn to the right, and the T-C would indicate a right turn.

In other words, the T-C lies...it tells you the wings are banked whether they are or not.

I think, from reading the user's manual I got from the Trutrak Web site, that the Pictorial Pilot is a rate instrument. It "lies" just a spinning-wheel gyro-based turn coordinator. It has a horizon that it tilts, but it indicates turn rate, not bank angle. When it's deflected to its mark, it means "standard rate turn" not "your wings are tilted x degrees."
 
And that is why turn coordinators (And the trutrak) have the slip-skid indicator on them. If the airplane is coordianated, then yaw rate implies a bank. And it works great for IFR, as it's not terribly important how much the wings are banked, but which direction (and how to get to wings level and when you reach that point). And it's the same for pitch.. It doesn't matter if you're pitched up 5 or 10 degrees, you just need to know where level flight is.

So to answer the original question (from what I have found), the trutrak is a rate-of-turn and vertical-speed indicator, and it simply displays those quantities using an easier to interpret and more familiar artificial horizion-like display.
 
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