Höhenmesser Fl 22320

[Rodolphe]

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Dear Komrades,

 

Following a thread on the Bf109 F-4 instruments on another section of this forum, I'm searching for some information on the two index "E" and "F" fitted on certain types of altimeter used by the Luftwaffe as the model Fl 22320 (see hereunder).

What are the purposes and utility on those movable bugs ?

Your help will be greatly appreciated.

 

Best regards,

 

Rodolphe

 

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[JtD]

The altimeter has a small adjustment wheel on the bottom of the instrument. This is used to adjust the indicators according to atmospheric pressure variations. Procedure was to adjust it for airfield altitude (zero altimeter on the runway) and then for sea level 0m (set altimeter to known airfield altitude). You see the little white triangle in the middle between E and F? This is an indicator you move while setting the altimeter up. The position of this indicator was marked for the runway set-up with the red E-triangle, and for the 0m set-up with the red F-triangle. In flight, you could then switch back and forth between a display of altitude above 0m and altitude above airfield by moving the white triangle back and forth between the F and E settings.

 

Naturally, altitude above 0m would be more interesting in normal flight, so usually you'd use the F setting, but for landing altitude above the airfield was more interesting, so you'd use the E setting.

 

As has been mentioned in the French forum, the letters E and F are used because it is short for QFE and QFF, official abbreviations for current air pressure at the airfield and at sea level.

[Rodolphe]

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Thanks for the explanations.

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[Flyingpencil]

That is an amazing bit of technology!

 

Why this is not standard in GA aircraft is beyond me!

I want to get me on to install in my Cessna 172!  (when I get one, LOL!)

[Crump]

It is called an altitude bug. You can get them at Sporty's for your C172.

[BlitzvogelMcpeek78]

Why get a c172 they are awfully expensive. How about a CH 200 250 300 or 350. Got my CH 200 for $7000. It's powered by an O-300. Say why not an tennie two. Yeah I know everyone thinks one searter sucks because you cant take anyone with you, but take my advise YOU WILL DO MOST OF YOU FLYING ALONE! Most pilots will tell you this

[Flyingpencil]

It is called an altitude bug. You can get them at Sporty's for your C172.

 

Oh, sure, I can get suction cup with hook and use that, but that device lets you easily switch between 2 settings.

 

But these days glass screens do that for you.

[Flyingpencil]

Why get a c172 they are awfully expensive. How about a CH 200 250 300 or 350. Got my CH 200 for $7000. It's powered by an O-300. Say why not an tennie two. Yeah I know everyone thinks one searter sucks because you cant take anyone with you, but take my advise YOU WILL DO MOST OF YOU FLYING ALONE! Most pilots will tell you this

 

I usually manage a passenger most of time.