i have a question !

[flightland]

hi
my name is reza
im student pilot
now
i styding at ground school of ppl
my structor asked this qestuon but unfortunately i coudnt find the answer
his question is :
why in some airspeed indicator of some airplane the beginning of white arc and green arc is the same and in some other airplane is not the same (why some times the Vso & Vs1 is the same and in some other airplane is not the same )
in the ppm book there is these diffrence between definitions of these tow speeds :
1-Vso is for dirty configuration
but
Vs1 is for
specified configuration

2-the frst one is for max landing weigh
and the second one is for max take of weigh
:rolleyes:i dont know
if you know my answer plzzzzzzzzzzzzz ...
thx a lottttttttttt

[john_tullamarine]

One can only apologise for the unhelpful comments of those who have little interest in helping the newfolk in our Industry.

First, current definitions are at FAR 1.2 (http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&sid=53663c98faf38aee58254dbed30ca10e&rgn=div8&view=text&node=14:1.0.1.1.1.0.1.2&idno=14)

Second, current ASI marking requirements are specified in FAR 23.1545 (http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&sid=53663c98faf38aee58254dbed30ca10e&rgn=div8&view=text&node=14:1.0.1.3.10.7.105.16&idno=14)

(For both references, the usual caveat applies - when talking specific Types, the relevant frozen rules relevant to the design need to be looked at).

In respect of your specific questions, presuming that the instrument has been marked correctly - there are aircraft out there with instruments swapped from other aircraft without the markings being corrected and, no doubt, those with just normally occuring errors.

why in some airspeed indicator of some airplane the beginning of white arc and green arc is the same and in some other airplane is not the same (why some times the Vso & Vs1 is the same and in some other airplane is not the same )

If the thrust of the question is "why is Vs0 not the same as Vs1" then

(a) generally, the two values relate to stalls in two quite different configurations so it would be quite unusual to find that they ARE the same.

(b) .. unless, of course, we are talking about a simple small aeroplane without flaps, with fixed undercarriage, and for which MTOW = MLW .. for which the two stall speeds WOULD be the same.

[mattyj]

..yes but why would there be a white arc if there were no flaps?:confused:

[john_tullamarine]

..yes but why would there be a white arc if there were no flaps?http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/confused.gif

Now, what a good point ... obviously, I opened my mouth prior to making sure that my brain was engaged :ugh::ugh::ugh::sad:

Reminds me of an occasion decades ago when Julius Sumner Miller posed a question over coffee to the assembled academic staff at Sydney Uni .. would a cutout in a steel plate get bigger/smaller when the whole was heated ? .. legend has it that Harry Messel, with a throw away answer lacking consideration, opined "smaller" .. from which we should all take the lesson that one should ensure the brain really is in gear prior to opening one's mouth ...

The references are still useful for the OP so they can stay there.

However, we will all need to wait for someone brighter than I to come up with a better answer, I guess....

DJPil should be able to offer a comment, I'm sure.

[Frank Arouet]

flightland;

If Pilko can't answer your question, ask Jabawocky who has a mate flies a big biplane that has a taxi, take off, stall, approach and cruise speed all the same.

But otherwise remember ignorance is bliss. Just strive to be the happiest man on Earth.

Where do you fly, by the way?

[tail wheel]

Where do you fly, by the way?

flightland is located in Iran.

[Ascend Charlie]

Hey, Tulla

The majority of folks here wouldn't have a clue who JSM or Hairy Missile are/were, and would like to have it explained that the hole behaves exactly as if it were still filled with metal, and would expand.

Ohh... I already explained it, Corcoran. Why is it so???:8

[djpil]

DJPil should be able to offer a comment, I'm sure.
As some-one said, I was waiting to see what particular aircraft types raised the issue. Even CAR 3 had the white arc down to Vso. Perhaps JT has a copy of BCAR Sect K or ANO 101.22?

The ASI in this Airtourer (http://www.victa.accesspoint.net.au/index_files/airtourervhmufcockpit.htm)seems to have the bottom of the green at the top of the white?

I get confused by the those American aeroplanes with the ASI marked with speeds in CAS per the early FAR 23 (http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgFinalRule.nsf/0/1918F11D69D6C14D86256BBC0053CC3D?OpenDocument).

[john_tullamarine]

Reza,

If djpil and I are confused with a combined total of lots of years in certification .. perhaps you could go back and check with your instructor that you had the question correctly noted down ?

[flightland]

thx foe your answers
i found very good firends at this forum
like you
yeah
im confused too
yeah
that is the correct qouestion
i need a reson for this diffrence

[Enema Bandit's Dad]

Flightland, how regulated is aviation in Iran? I gather that they probably don't have an aeroclub scene? How do you go about learning to fly over there other than joining the airforce? What do you learn in and how much does it cost? Thanks. :)

[john_tullamarine]

yeah that is the correct qouestion i need a reson for this diffrence

maybe you could ask your instructor for his answer and then post it for consideration ?