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  #21  
Old 11-29-2018, 09:44 AM
rongawer rongawer is offline
 
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Location: Brentwood, CA
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Quote:
Originally Posted by AirHound View Post
.....the Van's POH that states 12 KT max crosswind and 35 max total wind.

I understand Cross Wind, Demonstrated Cross Wind, etc.....

What is maximum total wind? Does that mean ' max surface wind conditions' ...therefore, it better be tied down and secured or in the hanger?....OR?
I take that to mean the maximum wind in any direction. I took off this morning with a 17KT direct XW from the right, gusting to 20KT without issue. Based on that, I'd say 20KT XW is quite doable.

I just passed my first 100 hours in the RV12, but I'm going to limit my operation to 35KT maximum wind from any direction until I get another 100 hours or so. My opinion is that landing and taking off in XW is very controllable with plenty of authority (great rudder), but steering after landing and taxiing are a bigger challenge, IMHO.
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  #22  
Old 11-29-2018, 12:45 PM
pilotyoung pilotyoung is offline
 
Join Date: Jan 2018
Location: Birmingham, AL
Posts: 124
Default Maximum Direct Crosswind Component

I appreciate all the comments in this thread and in another one that I started. I still have one question.

Does any know, and maybe someone from Van's can chime in here, did Van's intend the "Maximum Direct Crosswind Component" to be a limitation? As has been discussed, all other POH's that I have read have "Maximum Demonstrated Crosswind Component", and that is not a limitation. Van's left our the word demonstrated.

So I presume that Van's considers this a limitation. But I am still wondering why. Is it the light weight? Light wing loading? Is it mandated by the Light Sport regulations or certification requirements?

It does not matter for flying. I am going to fly conservatively but I would just like to know the reason.

Thanks.

John
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John D. Young, RV-12 Owner
Serial Number 120022, N6812Y
Bought it as a flying airplane in Feb. 2018
Just passed 140 hours flight time in RV-12, and 10,000 hours mostly in corporate jets. I am a CFI; CFII; MEI; and a advancd Ground Instructor, CFIG; and hoping to be able to help new RV-12 owners by doing some transition training for new builders and owners in RV-12's.
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  #23  
Old 11-29-2018, 12:56 PM
rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
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Quote:
Originally Posted by rongawer View Post
I take that to mean the maximum wind in any direction. I took off this morning with a 17KT direct XW from the right, gusting to 20KT without issue. Based on that, I'd say 20KT XW is quite doable.
Just keep in mind that a left cross wind is the direction with the most influence on controlability during a take-off or go around because it turns the airplane to the left along with engine torque and p factor.

I right crosswind is helping to counter the torque.
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  #24  
Old 11-29-2018, 01:53 PM
AirHound AirHound is offline
 
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Location: OFallon IL now, everywhere before
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Originally Posted by rvbuilder2002 View Post
Just keep in mind that a left cross wind is the direction with the most influence on controlability during a take-off or go around because it turns the airplane to the left along with engine torque and p factor.

I right crosswind is helping to counter the torque.
.................................................. ............
Hey Scott!

Are we close with our interpretations of POH.. 'Max Total Wind'?

The word 'Total' is an interesting description...Doug in IL
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  #25  
Old 11-29-2018, 03:14 PM
rvbuilder2002 rvbuilder2002 is offline
 
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Originally Posted by AirHound View Post
.................................................. ............
Hey Scott!

Are we close with our interpretations of POH.. 'Max Total Wind'?

The word 'Total' is an interesting description...Doug in IL
Think of it as max in any condition.... steady state or gust.
Examples -

If the steady state wind is 35 with no gust value, and the calculated cross wind component is 11 Kts or less, you are good.

If the steady state is 25 with gusts no higher than 35, and the calculated cross wind component is during a 35 Kt gust is 11 Kts or less, you are good.
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  #26  
Old 11-29-2018, 03:15 PM
rgmwa rgmwa is offline
 
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Originally Posted by rvbuilder2002 View Post
If you get out your wiz wheel and calculate the actual cross wind component for a condition where the wind is 15 Kts directing perpendicular to the runway, because of fwd movement aligned with the runway heading, the crosswind component wont actually be 15 Kts. It is 9 Kts
That is why you have seen me post here that I have made landings in conditions where the wind was at 15 Kts, perpendicular to the runway.

To reach the published maximum of 11 Kts, the perpendicular steady state wind would have to be 18 Kts.
This might be a dumb question but I'm struggling to see this. If the steady state wind is blowing 10 knots directly perpendicular to the runway and the plane is moving at 10 kts down the runway, the relative airflow over the plane will be about 14 kts at 45 degrees to the direction of movement. However the crosswind component that the plane sees will still be 10 kts. Am I missing something? What is the speed of the fwd movement in the two examples above?
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  #27  
Old 11-29-2018, 03:27 PM
rvbuilder2002 rvbuilder2002 is offline
 
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Quote:
Originally Posted by rgmwa View Post
This might be a dumb question but I'm struggling to see this. If the steady state wind is blowing 10 knots directly perpendicular to the runway and the plane is moving at 10 kts down the runway, the relative airflow over the plane will be about 14 kts at 45 degrees to the direction of movement. However the crosswind component that the plane sees will still be 10 kts. Am I missing something? What is the speed of the fwd movement in the two examples above?
Aircraft speed doesn't matter.

Look at any calculator (even an old E6B) there is no input for aircraft velocity.

BTW I corrected the calculated crosswind component in my other post..... I had fat fingered the wrong runway heading in the calculator.
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Last edited by rvbuilder2002 : 11-29-2018 at 03:31 PM.
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  #28  
Old 11-29-2018, 03:38 PM
rgmwa rgmwa is offline
 
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Quote:
Originally Posted by rvbuilder2002 View Post
Aircraft speed doesn't matter.

Look at any calculator (even an old E6B) there is no input for aircraft velocity.

BTW I corrected the calculated crosswind component in my other post..... I had fat fingered the wrong runway heading in the calculator.
OK. I still don't get it. Back to the drawing board.
So what was your runway heading in the above examples?
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  #29  
Old 11-29-2018, 05:02 PM
rvbuilder2002 rvbuilder2002 is offline
 
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Originally Posted by rgmwa View Post
OK. I still don't get it. Back to the drawing board.
So what was your runway heading in the above examples?
360

Wind from 270
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  #30  
Old 11-29-2018, 05:16 PM
rgmwa rgmwa is offline
 
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Originally Posted by rvbuilder2002 View Post
360

Wind from 270
Well, thatís a crosswind alright. Thanks!
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