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  #11  
Old 01-23-2007, 07:53 PM
WannaBRV WannaBRV is offline
 
Join Date: Sep 2006
Location: clovis
Posts: 18
Default Interesting picture

Haven't flown through any of it but here is a picture from the ground. I loved it but didn't have the camera to take a high quality picture. I really liked all the layers that were formed I love lenticular clouds (From the ground that is )

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  #12  
Old 01-23-2007, 08:28 PM
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RV6_flyer RV6_flyer is offline
 
Join Date: Jan 2005
Location: NC25
Posts: 3,507
Default

CAT at 8,500. "G" meter recoreded +5.5. I forget what negative was but my head hit the canopy kind of hard as I remember my head hurt.

I was using Flight Following With Joshia Approach and was North Nortwest of PMD VORTAC heading toward KTSP in cruise flight at WOT and 2,500 RPM. Was somewere between 163 and 166 KTAS.

When it hit, I pulled the throttle and remember going up 1,500' above my crusing altitude. When it was all over, I was doing about 90 KIAS and was 1,000' below the altitude that I started at. I notified Joshia Approach what happened.

I now slow down more than a lot of others in turbulance because of this experience. Yes Tehachapi is known for turbulance, updafts, mountain waves, and great sailplane flying.
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  #13  
Old 01-23-2007, 10:46 PM
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az_gila az_gila is offline
 
Join Date: Jan 2005
Location: 57AZ - NW Tucson area
Posts: 10,011
Smile 17,500 ft over Wrightwood...

How about flying with 4 or 5 other sailplanes at 15,000 to 17,500 ft over Wrightwood, just 10 miles or so outside the Los Angeles Class B Mode C veil area watching jets below you go into Ontario airport...

No transponders, and knowing we don't show up even as secondary radar returns since we have zero ground speed (Moving Target Discrimination is standard) .... I tried calling LA Center on the frequency shown on the sectional, and they wouldn't answer or acknowledge - perhaps because of the "glider" in the call sign....

I called FSS, and they said they would pass a warning on to the Center, but I've always wondered if anyone knew we were there....

A rare Mojave wave flying day in summer with a SSW wind high over the San Bernadino mountains, but easy thermals to climb on the desert side.

The usual Mojave wave is created by the Tehachapis and Sierras like Gary S. mentioned, with spring being the best time.... I got my Diamond Altitude soaring badge directly over the Mojave airport with a gain of 16,600+ ft from a 1800 ft tow to the rotor... blowing like h^&* on Hiway 395 at Mojave and calm at California City for landing... just perfect...

Gil in Tucson... but flew sailplanes a lot in the Mojave desert...

Forgot to mention the near mid-air with a large bundle of toy balloons at 16,000 ft... they must have been blown out of a vendor's hand at Disneyland or somewhere, but it really surprised me...
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Last edited by az_gila : 01-23-2007 at 10:54 PM.
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  #14  
Old 01-24-2007, 12:24 AM
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osxuser osxuser is offline
 
Join Date: Aug 2005
Location: Pasadena CA
Posts: 2,484
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Not a great place to be.... I'll keep an eye out for you glider types around there.

My worst was coming out of north vegas in a Glasair IRG. Headed up toward red rock paralleling the peaks. Mistake #1: Go for the penetration, not the parallel, got +-3G's, airplane mostly out of control until we headed back away and re-evaluated options...
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  #15  
Old 01-24-2007, 12:41 PM
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rv8ch rv8ch is offline
 
Join Date: Feb 2005
Location: LSGY
Posts: 3,198
Default Wind and mountains - scary stuff

Standard practice here for VFR flying is to check the wind reports. It's a small country, so the reports are quite accurate for all of the Swiss alps. Flying when the reports recommend against it is about as dumb as flying into known ice without proper equipment. It doesn't take but one encounter with either to make a believer out you.
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  #16  
Old 01-24-2007, 09:28 PM
glider4 glider4 is offline
 
Join Date: Sep 2005
Posts: 136
Default Wave issues

Like Alex, I'm a former CFIG with about 2,600 hours in gliders. Been to 27,000 in wave over Mojave and Reno. Has a TWA 747 vectored around me at Reno at FL250 by ATC. OAT was -50 degrees F. FUN!

There are four primary indicators of mountain wave. Waves
typically begin to form when :
1) winds across mountain peaks exceed 25 knots,
2) the wind direction is within 30 degrees of
perpendicular to the line of the mountain ridge,
3) wind velocity increases uniformly with altitude, and
4) wind direction is relatively constant with altitude.

A couple of recommendations from our friends at TRACON on managing mountain wave conditions:
If flying into a headwind & you're at best rate of climb (Vy), & YOU ARE
GOING DOWN FASTER THAN YOU SHOULD BE GOING UP, SPEED UP
TO CRUISE SPEED.

If flying with a tailwind and you're at Vy, AND YOU ARE
GOING DOWN THREE TIMES AS FAST AS YOU SHOULD BE GOING UP,
SPEED UP TO CRUISE SPEED.

THE GREATER THE HEAD WIND, THE SOONER YOU SHOULD INCREASE
TO CRUISE SPEED.

All else being equal, IT'S BETTER TO FLY DOWNWIND AND
FAST.

I would add to the above that if you are flying parallel to the ridge, downwind of it, and in sink, you should move either upwind or downwind to get to the neutral or up side of the wave. Be sure to avoid entering a lenticular if you are VFR. Crossing ridges should be done perpindicluar to the ridge line to minimize time spent passing through the wave and the associated sink areas.

All this assumes you are not in rotor. Rotor typically extends as high as ridge altitude but I have seen it up to a couple of thousand feet above ridge height. If you are in the rotor you need to slow down below maneuvering speed. Rotors can and will flip you upside down or worse... Slow down in rotor! The good news is that the wave's area of lift is usually found just upwind of the rotor.

Fly safe!

Al Thomas
N880AT (reserved)
RV-8A (fuselage)
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  #17  
Old 01-24-2007, 10:30 PM
BruceW BruceW is offline
 
Join Date: Aug 2005
Location: Elk Grove, CA
Posts: 122
Default Wishing for Wave

Last Sunday (1/21/07) was a great wave day in the SF Bay Area.
I was towing out of Byron to the lee side of Mt. Diablo. The northerly
winds were perfect. I'd drop the gliders at about 6K and they would
ride the elevator on up in 2-3 knots lift. One glider made it to over 20K
on a 3849' peak. Not bad. Nother x-country addic flew south to Loma
Prieta near Santa Cruz, rode the wave up, flew over to Half Moon Bay,
hit another wave and made it back to Byron by nightfall.

As a former glider pilot, I really wish I had the long white wings instead
of the noisy engine up front. It was one of those days with perfect
conditions. I was just glad to be part of the action. BTW, the tug is
a Scout.

Bruce W.
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  #18  
Old 01-25-2007, 07:11 AM
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Nuisance Nuisance is offline
 
Join Date: Feb 2006
Location: Pagosa Springs, CO
Posts: 130
Default careful!

You guys are making me nervous with the advice to dive through the downdraft. Mountain waves are often smooth, but they can get real turbulent in an instant. You really should be at manuvering speed or turbulent air penetration speed (usually about the same). And so, if you are going to slow down, you might as well leave the power on and climb when you can.

John
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  #19  
Old 01-25-2007, 10:07 AM
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mike newall mike newall is offline
 
Join Date: Jan 2005
Location: Yorkshire, England
Posts: 2,052
Default

2 stories, one good, one interesting.

Before I flew Airbusses for a living, I hauled skydivers in a Cessna 206 in the UK.

We had a range of hills (no mountains in the UK really) to the west and when the wind was steady and strong, we used to get cracking wave of the hills. I used to hook into this and the old 206 went from a plodding 500fpm to an awesome 1200fpm when I got it right.

To watch their faces when I called running in after 10 mnutes airbourne was great !

Now, go on a few years and I am sat fat, dumb and happy reading the paper in my A320 going to Palma Majorca in the Med. We are crossing the Pyrenees mountains and it is windy but we don't care, it's a tailwind. We are at FL370 and .78 Mach. The speed vector starts to fall, we slow down, the thrust comes up, we slow down some more, we get to green dot, our min clean speed, then leave FL370 !

Yep, caught in the lee wave and nothing was stopping us from going down, we lost nearly a thousand feet before it stabilised, I called ATC to warn them and fortunately no one was around.

In the same wave as in the Cessna case, I also rode my Aeronca Champ up to 11,000 feet one day, took 10 minutes to get up and 30 to get down !
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  #20  
Old 01-25-2007, 11:19 AM
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rv6ejguy rv6ejguy is offline
 
Join Date: Mar 2005
Location: Calgary, Canada
Posts: 5,766
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I've got a couple more for you:

A friend with a Citabria got caught in a downer just in the foothills near the Rockies here. He was solo, light on fuel and for a good 15 minutes descended under full power from about 10,000 down to the highway, looking at semi trailer tops and resigned to putting it down there, hoping to dodge traffic. At about 150 feet, he was able to maintain altitude and finally get out of it. Again, the descending air can't go below ground level but he had to get fresh underwear afterwards.

I was cruising at 9500 in a Tiger. Two on board 3/4 fuel, 100 miles from the mountains and started to lose altitude, kept advancing the throttle and pulling back to maintain. Finally had full power and best climb and still going down at 300 fpm. Smooth as glass. 5-6 minutes later, we were out of it and back up to 9500, reduced power and continued on our way. Weird.
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