What are these markers on the IAS Gauge?

[BTTW-DratsaB]

I was wondering what these three markers indicate on the IAS gauge:

 

I think they could be useful if I knew what they where. Manual doesn't seem to have them. They might be a new addition with the new cockpit?

 

I guess it is min speed(1), max speed(3), cruise speed(2)?

[lxsapper]

I also don't know, but 3 is likely to be Max speed it's just after plane starts shaking. 2 might be cruise. Stall speed is way below 1, so it can't be that, maybe best climb?

[Spetz]

Maybe in this order:

 

Best maneuver speed

Best cruise speed

Max speed

[Lizzard]

I would guess

 

minimum speed for safe flight

best turning/corner speed

max speed

Edited October 8, 2013 by Lizzard

[26-J39]

My guess :D

 

Minimum cruise speed.

Best/nominal cruise speed

Max speed

[Britchot]

No one mentioned flap extension speed. Perhaps #1 is the max speed for landing flap deployment and #2 is for combat flaps without the risk of damage. The landing flap sounds reasonable but I'm skeptical of the combat flap theory. If I have a chance to test it out later, I will.

[LeVince]

In FC2 the 3 markers are are between 600 and 650 this weird

[Mechanist]

Actually you can set these needles to anywhere you want in the real Su-25.

 

One common use is to set these needles to match waypoint speed. Mostly because waypoint flying in ground attack planes requires to TAS and not IAS. As you can set the needles in the around the IAS ring (and do the math before take off) it is easy to check if you're going with the required speed in the predefined altitude. The needles are colored for a reason, so you can easily remember what you set on them.

 

Also you can set it to any desired speed like, economy cruise, max combat speed (depend on you loadout) etc.

 

It is strongly advised that you set these needles before takeoff, due to these needles are hard to set when you have your flight gloves on, usually set with finger nails.

 

Su-25A is fitted with KUS-2 (Кус-2) or KUS-3 (Кус-3) combined IAS/TAS gauge. The two versions have more or less the same front panel.

 

Here are some pictures to explain this better. KUS-3 (Кус-3):

 

[BTTW-DratsaB]

That pretty interesting, thanks,

 

Maybe if we get click able Frog pit we can set them our selves!

[whitehot]

nice pics. I thought this kind of gauges had a glass or something over them

[Bucic]

nice pics. I thought this kind of gauges had a glass or something over them

There are glass panes for sure. It's just the markers are outside.

 

On the OP question - I'm sure the guy who builds Su-25 sim pit using real gauges knows the answer :) What's his name?

 

From me:

Airspeed indicators* are often scaled and oriented in such a way that certain important airspeed values come out in some characteristic manner, e.g. minimum speed is when the pointer is horizontal, right, corner speed - pointer vertical, pointing downward etc.

 

As indicated airspeed varies with altitude it may be impractical to have e.g. a rotatable airspeed indicator :) The markers are probably used by pilots to set more precise values based on their intended mission profile (e.g. mountainous region) and pre-flight performance chart analysis.

 

*other indicators as well. A matter of ergonomy.

[Suchacz]

Let me guess that the #1 mark is the optimal climbing speed... :huh: