Confusing Airspeed Indicator

kontiki

kontiki

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Kontiki
We have this Airspeed Indicator in a flying club T-34B Mentor. I'm not sure how to read it! There are copies of an old NAVAIR T-34B POH on the internet, the airspeed indicator shown in it looks entirely different.

Anybody know what it is or how to read it.
 

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Looks like glider ASIs. Indicator loops round more than once. My guess is you read outer speed first, then inner speeds.

(Disclaimer: no time in type)
 
Start on the outer ring, add a zero, 60, 80, 120, 140, 160, 180, then transition to the inner ring 200, 220, etc. Given red line is just beyond 200, you probably won't be using the inner ring much. The needle just goes beyond the full 360 degrees as speed increases, while maintaining a large enough scale at all speeds. It assumes you would know the difference between 0 and 200. Probably not original to the T-34B, as it probably will never go 400 kts!
 
Like midwestpa24 says. But just asking, do the markings match up with the flight manual? Is the green arc really 62-155 KTS? Vne really 210 KTS? Is that the same instrument that the plane was born with?
 
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kaiser said:
Looks like glider ASIs. Indicator loops round more than once. My guess is you read outer speed first, then inner speeds.

(Disclaimer: no time in type)
Click to expand...

My guess is you read the inner ring first (20 through 40 knots) then switch to the outer ring (60 through 180 knots).
 
Maxnr, We have a copy of Navair 01-90KDB-1, (POH available on the internet) with a couple typewritten sheets of data in front or ours that contains FAA approved info (with no signature). I checked the air speeds and limitations against the Type Certificate (5A3-Civilian Model D45) and it looks right. Navair 01-90KDB-1 does have a picture of a different original indicator. It's just another old different airplane.
 
sarangan said:
My guess is you read the inner ring first (20 through 40 knots) then switch to the outer ring (60 through 180 knots).
Click to expand...

I thought that at first, then changed my mind. Mainly because the top of the yellow and the red line are marked for the inner ring. I see no reason for 22 kts to be redlined, but 220 makes more sense.
 
kontiki said:
Maxnr, We have a copy of Navair 01-90KDB-1, (POH available on the internet) with a couple typewritten sheets of data in front or ours that contains FAA approved info (with no signature). I checked the air speeds and limitations against the Type Certificate (5A3-Civilian Model D45) and it looks right. Navair 01-90KDB-1 does have a picture of a different original indicator. It's just another old different airplane.
Click to expand...
Right on. I had an experience back in my 135 days when I was assigned an old A/C. I had a nagging feeling that something was not right. Couldn't nail it down. Three days with this A/C and I finally noticed the ASI on the pilot's side had the red line on the wrong A.S. I wrote it up and the Maint Mgr. faced off with me. He had the parts catalogue and I had the flight manual. Turned out they had replaced the ASI with one for the correct A/C type but wrong varient. Vne10 KTS too high. They stuck a Dymo label on the glass indicating the correct Vne and returned the A/C to service.
This complied with FAR 91.9 (b) 1 & 2. I have seen your querky double scale before on engine instruments.
 
Maxnr said:
Right on. I had an experience back in my 135 days when I was assigned an old A/C. I had a nagging feeling that something was not right. Couldn't nail it down. Three days with this A/C and I finally noticed the ASI on the pilot's side had the red line on the wrong A.S. I wrote it up and the Maint Mgr. faced off with me. He had the parts catalogue and I had the flight manual. Turned out they had replaced the ASI with one for the correct A/C type but wrong varient. Vne10 KTS too high. They stuck a Dymo label on the glass indicating the correct Vne and returned the A/C to service.
This complied with FAR 91.9 (b) 1 & 2. I have seen your querky double scale before on engine instruments.
Click to expand...
Amazing what you notice staring at an instrument panel for hours. :D

And how much maintenance likes to believe pilots know what they’re talking about. :rolleyes:
 
Where does one find a flying club with a T-34?
 
Auburn,

Memphis Navy Flying Club. I'm told the T-34 we have may be the last one owned by the Navy.

A few years ago they opened up membership to veterans that had an honorable discharge. I was renting to stay current, when they opened up the membership I jumped at the opportunity, I wanted to be part of a group with a good safety culture.

Rules for the club are tighter than the FAA rules. I got a good review with their CFI checkouts. It helped me address a few bad habits no one had called me out on before. Even now, I'm starting to address things no one pointed or really emphasized before on the basics. I know more than a few members from work so it's all good for me.
 
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It's this one.
 

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