Aces High Bulletin Board

General Forums => The O' Club => Topic started by: Tupac on October 25, 2011, 08:57:25 PM

Title: Wind shear
Post by: Tupac on October 25, 2011, 08:57:25 PM
My instructor and I took the cherokee for a spin last night

http://www.youtube.com/watch?v=8Vln7-XOHEQ&feature=player_embedded

We never did more than 100 knots indicated
Title: Re: Wind shear
Post by: oakranger on October 25, 2011, 10:02:34 PM
My instructor and I took the cherokee for a spin last night

http://www.youtube.com/watch?v=8Vln7-XOHEQ&feature=player_embedded

We never did more than 100 knots indicated

That is cool.  Sound like a little hard landing but what do i know.  As for the four lights on the left side of the runway.  I notice that the first one on the rigt turn red and then next and the next as you where over the runway.  I understand that the lights help you on your approched by seeing white but as you are making an approch to land.  When they turns red like that as you right about to land, is that a good approch?
Title: Re: Wind shear
Post by: MachFly on October 25, 2011, 10:08:24 PM
160GS for a Cherokee is really fast. How was the transition to though the wind shear back down?


First when I read your post I'm thinking "what does wind shear have to do with spins?".  :lol
Title: Re: Wind shear
Post by: MachFly on October 25, 2011, 10:11:25 PM
That is cool.  Sound like a little hard landing but what do i know.  As for the four lights on the left side of the runway.  I notice that the first one on the rigt turn red and then next and the next as you where over the runway.  I understand that the lights help you on your approched by seeing white but as you are making an approch to land.  When they turns red like that as you right about to land, is that a good approch?

Those are called PAPIs (Precision Approach Path Indicator), they guide you in on a 3° slope. They are made for IFR flight, when your VFR you generally want to descend a bit steeper (however this depends on the aircraft).

(http://www.navfltsm.addr.com/papi.gif)

What you don't want to see is 4 red.
Given that he was on a Cherokee 3 white is perfectly fine. I haven't really flown the Cherokee much but I think it would even be fine with 4 whites, it does not have the best glide ratio.
Title: Re: Wind shear
Post by: EskimoJoe on October 25, 2011, 10:18:31 PM
"If red, you're dead."
Title: Re: Wind shear
Post by: Tupac on October 25, 2011, 10:30:47 PM
Landing was rough - yes I got below the PAPI, when you have a 35 knot headwind it's easy to do. It was my first landing in a Cherokee in a couple months.


I'm just gonna wait until my plane is fixed - I don't much care for the Cherokee
Title: Re: Wind shear
Post by: MachFly on October 25, 2011, 10:58:56 PM
Landing was rough - yes I got below the PAPI, when you have a 35 knot headwind it's easy to do. It was my first landing in a Cherokee in a couple months.


I'm just gonna wait until my plane is fixed - I don't much care for the Cherokee

Did they give you a date when they are going to be done?
Title: Re: Wind shear
Post by: Tupac on October 25, 2011, 11:35:42 PM
Did they give you a date when they are going to be done?

I'll have a rough estimate tomorrow
Title: Re: Wind shear
Post by: MachFly on October 25, 2011, 11:52:08 PM
I'll have a rough estimate tomorrow

Good
Title: Re: Wind shear
Post by: icepac on October 26, 2011, 09:19:10 AM
I understand the shallow final that showed red on the papi would be because you had plenty of runway to work with and that you might encounter shear very low on final that might remove too much of your airspeed margin.
Title: Re: Wind shear
Post by: Tupac on October 26, 2011, 10:53:47 AM
My frame of thinking was that I was high, and that I needed to get down to land, so I took some power out and immediately got below the glideslope

Cherokee flies a little different than the Cessna.
Title: Re: Wind shear
Post by: Pigslilspaz on October 26, 2011, 07:32:52 PM
Tupac, what happened to your bird?
Title: Re: Wind shear
Post by: Tupac on October 26, 2011, 07:36:01 PM
Tupac, what happened to your bird?

Cylinder #4 needed to be replaced, I needed a new muffler, and the alternator mounting bracket needed replacing. I thought the plane was going to be down for awhile so we decided to continue in the cherokee, but my plane will hopefully be fixed next week. My friend said I could stay as long as I need to with him
Title: Re: Wind shear
Post by: Pigslilspaz on October 26, 2011, 09:28:53 PM
Yeah, you should get that spinny thing fixed, kind of important.
Title: Re: Wind shear
Post by: NatCigg on October 27, 2011, 06:08:19 PM
where was the wind shear?
Title: Re: Wind shear
Post by: 2ADoc on October 27, 2011, 09:30:03 PM
THe landing wasn't that rough, you did get a little low, and probably a little slow, bad deal there.  But my main question is why were you flying in the right seat?  Your instructor should have been there and you should have been in the left.
Title: Re: Wind shear
Post by: Tupac on October 27, 2011, 09:37:30 PM
THe landing wasn't that rough, you did get a little low, and probably a little slow, bad deal there.  But my main question is why were you flying in the right seat?  Your instructor should have been there and you should have been in the left.

I did get low, but I wasnt slow. My groundspeed was about 30 so it did give the illusion of me being very slow. I was in the left seat, my instructor was in the right seat filming.
Title: Re: Wind shear
Post by: 2ADoc on October 27, 2011, 09:54:22 PM
Ah ok I thought you might have a hat mounted cam or something like that.  A ground speed of 30 hell that means you were in 40-50 knot winds that is ridiculous,  glad you didn't have to land with a cross wind.
Title: Re: Wind shear
Post by: Dichotomy on October 27, 2011, 10:11:53 PM
so are ALL the girls in Nebraska fat?
Title: Re: Wind shear
Post by: WYOKIDIII on October 27, 2011, 10:32:10 PM
so are ALL the girls in Nebraska fat?

nope

http://frathousesports.com/nebraska-cheerleaders-pictures?pid=1462
Title: Re: Wind shear
Post by: Dichotomy on October 27, 2011, 10:56:02 PM
they're all imports  :devil
Title: Re: Wind shear
Post by: WYOKIDIII on October 27, 2011, 11:04:22 PM
you never specified origin...just location  :cool:
Title: Re: Wind shear
Post by: flight17 on October 27, 2011, 11:39:49 PM
We had Wind Shear yesterday from the surface to 2000ft up to 45kts.
Title: Re: Wind shear
Post by: NatCigg on October 28, 2011, 06:23:54 AM
by definition is that not a wind moving in opposite directions.  this being most severe for aviation when a plane is on landing.  so, 45 knots of headwind could become .. say 45 knots of tailwind, thus a 90 knt change in air flow over the wing.  for a plane flying a 80 knot approach this would surely send the pilot into a frenzy and possibly the ground. ?
Title: Re: Wind shear
Post by: MachFly on October 28, 2011, 06:40:47 AM
by definition is that not a wind moving in opposite directions.  this being most severe for aviation when a plane is on landing.  so, 45 knots of headwind could become .. say 45 knots of tailwind, thus a 90 knt change in air flow over the wing.  for a plane flying a 80 knot approach this would surely send the pilot into a frenzy and possibly the ground. ?

Technically yes. In reality the numbers are not that high, if the wind changes 180 degrees than the wind speed is probably not more than 10. If the wind is ~30kts than it will stay in the same general direction, might switch 30 degrees but not much more. Also you can have wind direction staying the same but speed changing 20kts in a few hundred feet.
For example your on a final approach at 85kts and as you descend from 300ft AGL to 200ft AGL you loose 15kts of heading therefore lowering your speed to 70kts. At this point you got to make sure that you don't stall out.
Gusts can have the same effect and are a lot more common.
Title: Re: Wind shear
Post by: icepac on October 28, 2011, 07:39:17 AM
If you have plenty of runway length, carrying extra speed is the ticket.

If you're landing on a runway such as Woodbridge in Virginia (now gone) that's 2000 feet with high trees on each end, best to announce on unicom you are shooting a missed approach drill and buzz the runway while watching the airspeed indicator for abrupt changes as you descend.

Then land with the information you just gathered.

Also.....don't trust the tetrahedron since I have seen many stuck by weeds growing up under them.

My first solo cross country to a uncontrolled field featured a tetrahedron that was stuck pointing the wrong way and I sweated out a longer landing on a short runway than was comfortable.

Yes, I walked out, cleared the weeds and complained to the guy fueling the plane.
Title: Re: Wind shear
Post by: MachFly on October 28, 2011, 07:49:02 AM
tetrahedron

 :headscratch:
Is that that old metal wind "sock"? 
Title: Re: Wind shear
Post by: Tupac on October 28, 2011, 11:43:46 AM
:headscratch:
Is that that old metal wind "sock"? 

Yes. I like da tetrahedron. We've got a couple of them around here.
Title: Re: Wind shear
Post by: WYOKIDIII on October 28, 2011, 08:40:21 PM
You mean like this ?

http://www.wrds.uwyo.edu/sco/climateatlas/wind.html
Title: Re: Wind shear
Post by: flight17 on October 28, 2011, 10:14:22 PM
Technically yes. In reality the numbers are not that high, if the wind changes 180 degrees than the wind speed is probably not more than 10. If the wind is ~30kts than it will stay in the same general direction, might switch 30 degrees but not much more. Also you can have wind direction staying the same but speed changing 20kts in a few hundred feet.
For example your on a final approach at 85kts and as you descend from 300ft AGL to 200ft AGL you loose 15kts of heading therefore lowering your speed to 70kts. At this point you got to make sure that you don't stall out.
Gusts can have the same effect and are a lot more common.

Our sustained wing speeds were about 20Kts with mid 20's gusts. We have hills all around the airport and there is a drop off on the end of runway 28 (if you were using 28 for t/o or landing) in which there is a vally about 2000ft wide that runs perpendicular to the runway. Plus we have small mounds that are all scattered around the airport grounds that cause some wierd wind patterns. I call them mounds because they arent really hills, but its just where you can see they have cut back the land to put the airport in.