Turn and bank indicator

Hi Daz

If you were to fit it then you would also need an external venturi, or an engine driven vacuum pump and regulator, together with filters and hoses.
Chiron

Was having a look at the three-view of the aircraft this morning (for whatever reason), and there is a venturi on the underside of the fuselage. The photo is not too clear, but it is there.

The weight of this instrument is not so much the issue, ( 1.9 lb is still reasonable by today’s standards) it’s the weight of the vacuum system required to drive it. If you use an engine driven pump it will probably add a total of 5 to 6 lb. That may not seem much but every homebuilt I know of has finished up overweight, with the builder wracking their brain deciding what to leave out.
When you start building, step 1 should be to get a BIG sign for the wall that says “Simplicate, and add lightness”, then try and abide by it. I’ve seen this saying attributed to various people, usually Tommy Sopwith. (Historic forum connection there 😀 😀 😀 )
The pitot probe is not relevant to this instrument, but is used to drive the Airspeed Indicator, sometimes it’s also the place where static pressure is sensed, which is used by the Airspeed Indicator, the Altimeter and the Vertical Speed Indicator.

Chiron

Hi Daz

This type of instrument is used to indicate a standard turn rate, principally in IFR flying, for which I imagine your aircraft would not be eligible. (I’m not very familiar with your CAA reg’s.)
As to whether it needs overhauling, again it depends what the CAA and PFA say, but I would expect
that a functional check by an approved instrument repair facility may be sufficient.

The standard rate turn is 360 degrees in 2 minutes( hence the wording on the face) and is also sometimes called a rate one turn.
Here’s a link which explains what the indications mean:
http://www.allstar.fiu.edu/aero/turnandslipindicator.htm

Now the bad news.

‘Electrically powered’ versions often say as much on the front face, I’m guessing therefore that this one is vacuum driven. If you were to fit it then you would also need an external venturi, or an engine driven vacuum pump and regulator, together with filters and hoses. Finding a price for a pump (Part Number: 215CC) should help you decide – and this is the most common (cheapest) one!

Considering the added complication, expense, and most significantly weight, together with the limited panel space and usefulness I think you would regret installing it.
If you want more than the basic VFR instruments you may be better off with an electrically powered Artificial Horizon, which would give you bank and pitch information, but not turn rate?

Chiron

Thanks for that. I’m guessing, though, that since the aircraft was designed in the 1960s/70s, lighter instruments might not have been available.

The Isaacs Spit has just a basic VFR panel – including a turn and bank indicator, which is why I bought it.

It does have a wing-mounted pitot tube, if that helps?

(You can probably tell I know very little to sod-all about instruments!! 😮 )

This is still my favorite, vs. the newer style turn coordinator, for smaller VFR airplanes. And the slip-skid indicator is a must, until you have enough time where you can feel it in your @ss.

Hi Daz

This type of instrument is used to indicate a standard turn rate, principally in IFR flying, for which I imagine your aircraft would not be eligible. (I’m not very familiar with your CAA reg’s.)
As to whether it needs overhauling, again it depends what the CAA and PFA say, but I would expect
that a functional check by an approved instrument repair facility may be sufficient.

The standard rate turn is 360 degrees in 2 minutes( hence the wording on the face) and is also sometimes called a rate one turn.
Here’s a link which explains what the indications mean:
http://www.allstar.fiu.edu/aero/turnandslipindicator.htm

Now the bad news.

‘Electrically powered’ versions often say as much on the front face, I’m guessing therefore that this one is vacuum driven. If you were to fit it then you would also need an external venturi, or an engine driven vacuum pump and regulator, together with filters and hoses. Finding a price for a pump (Part Number: 215CC) should help you decide – and this is the most common (cheapest) one!

Considering the added complication, expense, and most significantly weight, together with the limited panel space and usefulness I think you would regret installing it.
If you want more than the basic VFR instruments you may be better off with an electrically powered Artificial Horizon, which would give you bank and pitch information, but not turn rate?

Chiron