Wake Turbulence

Frequently in central Washington we share the air with some pretty large aircraft. Military jets, Boeing out for a “test drive”, sailplanes, ultra-lights and so on. Of particular interest to me is the occasional “Heavy”. Boeing often test out variants of the 747 and in recent years The Boeing Dreamliner (787). On my last flight I had a 787 cross my course line and I was faced with trying to remember what a safe separation is for wake turbulence. (Been a very long time since I looked at my “From the Ground Up” training manual.

I found the following interesting training manual from the FAA:

http://www.faa.gov/training_testing/training/media/wake/04SEC2.PDF

In it I found the following:

“2.4.4 Vertical Motion of the Wake
The wake of an aircraft has behavioral characteristics which can help the pilot visualize the
wake location and thereby take avoidance
precautions.  The initial descent rate of the
wake is adequately described by classical
theory; the descent rate is determined by the
weight, flight speed and wingspan of the generating aircraft.  Generally, vortices descend
at the initial rate of about 300 to 500 feet per
minute for about 30 seconds.  The descent rate
decreases and eventually approaches zero at
between 500 and 900 feet below the flightpath.
Flying at or above the flightpath provides the
best method for avoidance.  Maintaining a
vertical separation of at least 1000 feet  when
crossing below the preceding aircraft may be
considered safe.”

Not a bad idea to glance through this article if you share the air with the big boys….

Icing on the Cake (season)…..

Overnight the NOAA Spokane soaring forecast perked right up (top of lift 10,000…. 500fpm climbs). The plans for a day at lake Chelan changed. My drooling over the soaring data caused Mia to give the old man one more opportunity to extract a few more K’ms out of the Columbia basin…. she agreed to run the rig! (I was wondering if this was going to cost me another bottle of Johnny Walker Blue?)

Like the “Flash” I had the glider loaded and by 11:30 we headed out (an early start). Along with a dramatically improved soaring forecast we saw cumulous development over the flats….. things where looking up!

It was NE at the tow site. Dang… a short low tow? To improve my odds, we moved the setup 2 miles further south to newly cut crop. Sure enough, 12:30,  2100ft agl tow, released into some nice smooth 200… then 300fpm up, let the games begin!

The first plan, establish wind direction. Looked to be a 6-12mph NW? … so it was a quick run to Wilson Creek, classic glides punctuated with well placed climbs between 8500 and 9500ft asl.  From Wilson creek I decided to tack on a little extra OLC distance by continuing on to the Hutterite community to the SE, climbed out and turn North East to Sherman (near Wilbur).

The run NE was also classic but the Q’s were not as well defined and would often just disappear… or appear randomly. East of Wilbur, I was having to work to find lift. Winds had switched more westerly and climbs stopped being reliable. I bailed on the Sherman turn-point and turned in the direction of L-Road.  At nearly 3 hours and 110kms into the flight, I knew this late season flight had potential to come of the rails… sure enough it did. 

NW of Wilbur I had one last climb that was the highest of the day just over 10,000ft asl (forecast was dead on!), after that everything ground to a crawl. Good dust devils no longer marked strong lift, short climbs, needed longer and longer glides. At this point, Mia joined up as my ground support (driving up from Almira , NE to the Highland silo landmark). From here she encouraged me to press on. The further west I pressed the lower the climbs topped out. By now it was a luxury to get over 7000ft. Once I was  as low as 3900ft asl (1500agl).  Looming ahead…Banks Lake.

Mia kept up the encouragement, I kept up digging up scraps to stay aloft, all while Mia waited at the exact field I had landed the day before.  One last climb to 6100ft asl, right near the edge of the lake. From here it would be at least a 12km glide  (and only 3500 agl to work with). This would of course not only include the lake crossing but to also reach a good LZ. Inspired by Mia’s previous day crossing of 5600ft asl (at the east side edge) and slender weak looking dust devil under the power lines on the West side SE of Mold cemetery, I went “for it”.

Of course I had to show off, I was even lower then Mia's flight, starting out on the east side at 5200ft asl (now only 2700ft over and still 10km’s to travel).  Fortunately, the tactic of getting to the West side of the lake paid off. With a very light NW surface the weak lift seemed to break with a little more strength over the cliffs on the west side of the lake and I was able to re-establish some improvement in my gains. One weak thermal on the edge to 6700ft agl let me push on NW, One more glass smooth 200fpm up allowed me to get over 7700 and suddenly, my glide to goal numbers turned in my favour! At 14km’s out I went on final glider to arrive at L+13 1800 ft agl. And that was it, not an inch of air was moving up, the day was done.

With a few tips about landing in the back of my head (from Andy Long, ATOS guru landing expert) and  Mia (the worlds best grounds crew and  a great pilot to boot) now at goal with a limp wind sock and kicking dust, stall alarm set,  I pulled off one of my nicest no wind landings ever (thanks to both Andy and Mia!)

6 hour, 180km FAI Triangle

Undoubtedly one of the nicest September long weekends in years. This last flight was the “Icing on the Cake” for this years season. In the distance we could hear the lonesome howl of some local coyote's, the sun was setting , Mia and I with bottles of Becks in hand took out the lawn chairs and enjoyed the last few moments of season (taking the glider down had to wait). This is a spectacular place to fly !

 

Cheers.

Just Another Day in Paradise

After Mike’s epic flight yesterday, he volunteered to drive the rig and Mia and I had the opportunity to get a little airtime. 

Soaring numbers where not bad, looked to be some west wind so I thought I would try and duplicate Mikes flight.  Lots of dust devils at the tow site with the winds switching from West to East and a little bit of North to allow a tow.

I was up first, Pinning off after a 1300ft agl north tow in some 500 up over L+13. The lift wandered off someplace (or I did) at around 3900ft asl. No panic as a good looking dust devil was brewing just SE of me. I did not quite take into account the heavy sink getting between A + B so I was happy to find some smooth lift at 1000ft agl and was able to work my way gently over to the real core as…. as “I got up to a good altitude to deploy?”. Truth is, dust devils at this time of year look much more intimidating then they truly are. Lots of bark but very little bite, guess it the fact the soil is as “dry” as it gets and sun is not quite as powerful as mid summer, this generates plenty of dust but not the power of the mid summer spectacles that deserve so much respect. Eventually I peaked out at 7500+ft asl and pushed south. In the meantime, winds delayed Mia getting on the tow rig (strong cross).  Mia was up and away (after a low save) as I reached Dry Falls heading to Wilson creek.

We had started off with a band of high cloud many miles to the NW but it soon became obvious that it was coming our way. By the time Mia had pushed a low easterly crossing of Banks Lake and I was heading north to Wilbur the high cloud started to become a factor. Mia managed to miss most of it by heading south toward Wilson Creek but I drove into the darkest of the shadow when I arrived in Wilbur. Soft lift was not going to be getting any better with high cloud cutting off the sun.

High cloud, taken by Mike in Hartline (note the Mammas cloud nested in the middle) :

Mia saw that things might get challenging and started working her way back to the lake and heading home. At one point as I struggled low near Almira I thought she had landed? Turns out she climbed out in a smooth 900 fpm having managed to escape the effects of the high cloud.  Eventually I cleared the shadowed area and was pushing NW but the ground was now being “scrubbed” by a stiff north breeze and only the strongest lift was breaking free.  Mia got one last gain and pressed west to Mold across Banks Lake. I on the other hand, could not find that last needed gain and landed in a nice smooth LZ picked out by our expert ground crew (wind sock, dirt kicking, cut field…. that Mike… what a pro….. what the hell he drank all the beer?)  In the mean time Mia had crossed but ran into the same decaying lift and was forced to land in a good Northerly breeze NW of Mold (perfect cut field).

Mia's 75km flat triangle, My 134km FAI (150 km attempt)

With a little bit of sadness our Mansfield season appears to have come to an end, soon it will be back to work and the grind of “life”. Mike, Mia and myself, tipped a couple Becks, chowed down on a big feed of pasta (boy can Mike put away the pasta!).

Till next year… maybe?

Guests…

Mia and I decided to sit out a day to accommodate some guests. Fiona Katay, a Canadian pilot visiting Chelan came out with our old friend Jeff Kohler (who live in McNeil Canyon near Chelan)  By rights, it would be completely unethical for us to tow Fiona as she had once flown for the enemy… the dreaded Alberta Rocky Mountain Hang Gliding League (nemesis of the West Coast Soaring Club)… she seemed nice enough… (besides Mia told me to be nice, so I did what I was told). Right away, like a typical Albertan, she pushed her way to the front of the line and took the first tow (just kidding… the men where too fat to stay up in the light air… so they made her go first). 

With plenty of dust devils and a light north wind, Fiona and her Light Speed S where up and away (she dug out a nice save near the start point on L-Road) 

 

Jeff soon followed on his 160 U2, by this time winds had shifted south so from the mid point setup we did a quick back track and set up for a south tow. Jeff got smacked a bit right on the end of the tow with good old flat land turbulence, but after a bit wandering about, caught a core and headed out.

Last, Mike yanked up south for a longer then normal and poor climbs just so he could perfect his low save technique (always the show off). Three tows, three away and the towline and chute recovered perfectly back to the rig each time = a good start to the day!

Towing, L-Road Mansfield WA, 09/02/2012

There didn’t seem to be any real set plan as our adventures head out into the wilds of central Washington. Nobody was really getting that high but a light westerly pushed everybody in the direction of Banks Lake , so Mike charged off with his VR in the direction of Wilson Creek. Fiona (with a vague understanding of the local landmarks) headed east with Jeff.  Jeff landed near Hartline,(30kms out)  Fiona made it to Creston but turn back to land near Wilbur (90km). With Mike still in the air after turning short of Wilson Creek and everybody else loaded in the Suzi we began to follow Mike slowly west. He was doing well after turning at Wilbur, but frankly I surprised he managed to stay up after 5pm! The little show off managed to not only make it back to the tow site he pushed on for a bit of tour and ended up Flying a 151km triangle.  We arrived back in Mansfield (after picking up groceries in Coulee City) Just a few moments after he landed. Unbelievably late for this time of year (near 7pm) leaving the boy breaking down in the dark on the front lawn.  He later hurt himself trying to fit his big fat head into the glider hanger (too big to get through the door?). Dinner feast and smiles all around. 

Still giving just a little more….

Ok, perhaps a little early for the demise of the season. Yesterday we did our first “Billy Burger Run”.  Our west tow road (School House) just north east of town was the start point with pretty good cycles from the west.  Mike was up first and I was blessed with Mia’s offer to test fly her VQ! (Mia decided to run the rig).

With a fresh west wind in both the forecast and reality we moved our towing operation to the seldom used School House Road, 2 miles ENE of town. Its a nice tow road but a little short (2 miles).

Devils were popping all around the area so I sent Mike to go find me some lift. He pinned off after a two mile tow and gradually climbed away and headed west (into a west wind!…. I’ve taught him well?) Not getting very high but encouraging for my flight.

Now… just a small list of challenges that started with my first flight on the VQ:

-broken shoelace (don’t you just hate that?) field mod and fixed.

-Radio not working (moved off frequency… and locked?) fixed.

-Lost my airspeed probe walking to the truck! (seems to be a problem with flying the VQ …. see previous posts )

-I then had to unclip to find my spare probe. (stashed in the nose) got my riser twisted when I clipped back in. fixed.

-Start the tow… Vario is awful quite…. sound is off. fixed in the air.

-Vario starts to fall down on its pivot… had to re-engineer the bracket after release. fixed

Top quality pre flight?

So, after all that… how does the VQ fly? I will write a full report later but for now it totally blew me away for how light and fast it rolled and handled. Once I got in the air I called Mike (who was struggling near Withrow) that it looked like a good day for a down wind dash to Wilbur airport and dinner at Billy Burgers (Ye old classic American dinning establishment…. a burger joint).  I came up 30 ft short of 10,000ft, just couldn’t get there. Both Mike and I had some challenging wild air landing at the airport but all ended well. (The VQ lands sweet… as Mia nervously watched me land in the bouncy air)

Billy Berger’s to Park Lake for a quick dip (just before the sun went down) and back to Mansfield. The season ain’t over yet! (looks like we are flying today again)

My 82km wanderings

Mikes 98km Race to Billy Burgers

XC season slides away….

(The Labour Day Long Weekend) We get accustom to how great the flats of central Washington can be, its sad when mother nature hangs up the “Closed for the Season” sign. I’m sure there will be plenty of days before the snow fly’s that will be wonderful for XC but loosing close to 4 minutes of daylight per day rapidly begins to suck the life out of the suns ability to produce the classic conditions that make this place perform.

Ok, The good… yesterday, got the lawns all trimmed up then off to a fantastic day at lake Chelan. Crystal blue water, perfect temperatures. The kind of stuff that regular “tourists” do.  The bad?… (the image above), The Jet stream is writhing around like a demented snake. Parked right overtop of us and dragging its winds into the lower atmosphere. Not so much that the wind is the issue, more the inability for the sun to heat the ground when it is being scrubbed by the cool breezes that are present when the Jet Stream comes to town. 

Looks like the trend will stay through the whole weekend. 

Randy and a crew of other Hang Glider pilots have headed up to Cache Creek / Savona and might fair better as they could get the chance to sit in the “eye” of the weather pattern. In Mansfield we will hope that the forecasts are wrong and the winds die down to let the sun do its job….. If not, It’s GREAT swimming weather!

Humming bird fuels up for the trip south?