flight Instruments on the Cheap

"Dick" wrote in message
news:fevPj.5393$Ux4.1316@trnddc07...
Thanks. Interesting and I've asked manufacturer if a higher mph range
might be made available.

I wonder what the downside of such an instrument is??

The up side (besides cost) is extremely good resolution at slow air speeds.
Especially 0 to 30, where conventional ASIs are usually less reliable, if
even calibrated in that range. I bought one from AS&S years ago calibrated
for a helo that wasn't bad, but not nearly as repeatable as a Hall in the
low speed range.

The only down side I recall is their reliance on gravity to oppose their
reading. They bump around a little bit on bumpy days, and of coarse are
useless when inverted. I don't recall much change on positive G's. They
seemed accurate in 2 or three G turns because the indicating disk is very
light weight. Just the zero and half G's loads were a problem.

It might be realistic to look at Dwyer Instruments; there are many
offerings. In particular, the $50 unit
http://www.dwyer-inst.com/htdocs/air...riesMWSpec.CFM is 0-55
kt, resolution of 0.2 kt. Accuracy is about 5% of reading. There are
mini-pitot based models, rising vane (as used on some ultralight type
craft I've seen) and these rotating units.

On Tue, 22 Apr 2008 20:23:30 -0500, "Maxwell" luv2^fly99@cox.^net
wrote:


"Dick" wrote in message
news:fevPj.5393$Ux4.1316@trnddc07...
Thanks. Interesting and I've asked manufacturer if a higher mph range
might be made available.

I wonder what the downside of such an instrument is??

The up side (besides cost) is extremely good resolution at slow air speeds.
Especially 0 to 30, where conventional ASIs are usually less reliable, if
even calibrated in that range. I bought one from AS&S years ago calibrated
for a helo that wasn't bad, but not nearly as repeatable as a Hall in the
low speed range.

The only down side I recall is their reliance on gravity to oppose their
reading. They bump around a little bit on bumpy days, and of coarse are
useless when inverted. I don't recall much change on positive G's. They
seemed accurate in 2 or three G turns because the indicating disk is very
light weight. Just the zero and half G's loads were a problem.

"GeorgeB" wrote in message
...
It might be realistic to look at Dwyer Instruments; there are many
offerings. In particular, the $50 unit
http://www.dwyer-inst.com/htdocs/air...riesMWSpec.CFM is 0-55
kt, resolution of 0.2 kt. Accuracy is about 5% of reading. There are
mini-pitot based models, rising vane (as used on some ultralight type
craft I've seen) and these rotating units.


That would certainly address the bumpy conditions issue. But the bumpy
conditions really aren't a problem even on approach. It doesn't actually
bump very much.

What kind of aircraft are you flying?

I don't fly, but enjoy reading and learning; unlike others, I TRY to
not do anything that even smells like trolling.

On Wed, 23 Apr 2008 11:54:34 -0500, "Maxwell" luv2^fly99@cox.^net
wrote:


"GeorgeB" wrote in message
.. .
It might be realistic to look at Dwyer Instruments; there are many
offerings. In particular, the $50 unit
http://www.dwyer-inst.com/htdocs/air...riesMWSpec.CFM is 0-55
kt, resolution of 0.2 kt. Accuracy is about 5% of reading. There are
mini-pitot based models, rising vane (as used on some ultralight type
craft I've seen) and these rotating units.


That would certainly address the bumpy conditions issue. But the bumpy
conditions really aren't a problem even on approach. It doesn't actually
bump very much.

What kind of aircraft are you flying?

Nothing wrong with that.

"GeorgeB" wrote in message
...
I don't fly, but enjoy reading and learning; unlike others, I TRY to
not do anything that even smells like trolling.

On Wed, 23 Apr 2008 11:54:34 -0500, "Maxwell" luv2^fly99@cox.^net
wrote:


"GeorgeB" wrote in message
. ..
It might be realistic to look at Dwyer Instruments; there are many
offerings. In particular, the $50 unit
http://www.dwyer-inst.com/htdocs/air...riesMWSpec.CFM is 0-55
kt, resolution of 0.2 kt. Accuracy is about 5% of reading. There are
mini-pitot based models, rising vane (as used on some ultralight type
craft I've seen) and these rotating units.


That would certainly address the bumpy conditions issue. But the bumpy
conditions really aren't a problem even on approach. It doesn't actually
bump very much.

What kind of aircraft are you flying?