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Wake turbulence...am I too cautious.
Posted: Sun Dec 18, 2011 6:00 am
by Bundy
Morning my fellow triking crusaders
I will admit to being highly cautious on take off with aircraft in front of me at the holding point. Once the aerie in front is rolling I immediately line up and wait. Depending on the wind I normally wait a lot longer than some of our collegues do before I start my take off roll due to my fear of the wake affecting my climbout especially just after rotation. I have noticed that I may be "irritating" the guys behind me
Am I waiting too long? It is in
still conditions that I really seem to be "wasting time"... even the PAX sometimes ask me "why are we waiting?"

The aircraft in front of me is ussually on downwind before I even start my roll. The reason why Im asking is that for a long time I was based at a very quiet airfield with little to no traffic at all.... now that Im at a busy strip... I dont want to take more time than is necessary to take off safely. Am I being too "anal" here?
How do you guys approach these situations?
Re: Wake turbulence...am I too cautious.
Posted: Sun Dec 18, 2011 6:43 am
by cornell
What are the size of the aircraft that you are waiting for
Edit:
Do what ever you comfortable with don't worry what the other guys think.
Re: Wake turbulence...am I too cautious.
Posted: Sun Dec 18, 2011 7:05 am
by Bundy
Have never taken off behind anything other than another trike Cornell... if it was any bigger than that then the guys behind me may as well get out... order a cup of coffee....
Perhaps I should add that I have not had a bad experience yet on TO due to "wake" issues..... thus my concern about shortening the length of time I am currently waiting in still conditions. With a breeze blowing across the runway the wake clears quickly and thus no real problem, its when there is
no wind that I seem to be hesitant. No one has ever "chirped" me but I also do not want to be holding things up more than I have to... dont know if Im making any sense here?
Its just that I have seen some nasty video clips on the effect of wake turbulence when close to the ground

Re: Wake turbulence...am I too cautious.
Posted: Sun Dec 18, 2011 10:13 am
by DarkHelmet
AFAIK Wake turbulence only appears once the aircraft in front of you starts flying. I always know where I expect to start flying and judge accordingly.
In the old days, when Propwash-Dave was still Big-D - I always rolled moments behind his take-off coz he would have a long roll and I would be airborne in a shorter space than he would. I would climb out above his prop wash
That is my rule of thumb...
Re: Wake turbulence...am I too cautious.
Posted: Sun Dec 18, 2011 10:20 am
by vernon11
Bundy.
What I did when flying trikes, and even now with fixed wing. I would give it about 45sec or there abouts. Take off and imidiatly turn out. I have never had any problems.

Re: Wake turbulence...am I too cautious.
Posted: Sun Dec 18, 2011 12:19 pm
by Dobbs
Hi Bundy, it is in the still conditions that the wake turbulence waits aroubd the longest, so if anything you are advised to wait longer under still conditions.
Secondly, Dark Helmet is spot on, wake turbulence is only generated when the wing is producing lift, so if you can get airborne before the trike in front of you, and climb at no less than his climb rate, you will be OK.
A rule of thumb is that wake tubulence settles at around 500 feet per minute, so waiting for the trike ahead of you to be on downwind before taking off is probably a bit conservative. Similarly, if there is a bit of a cross wind component, keep to the upwind side of the aircraft ahead of you, and again you will add in further cushion of safety.
Re: Wake turbulence...am I too cautious.
Posted: Sun Dec 18, 2011 12:50 pm
by Tailspin
Bundy
What i do is normally wait for the plane in front of me to turn X-wind and then i roll. Yea so what if the Dude behind you gets a bit

but it is how you feel comfortable. Rather be comfortable then have that shitty Sponge taste in my mouth.
Re: Wake turbulence...am I too cautious.
Posted: Sun Dec 18, 2011 2:11 pm
by Gyronaut
My 2c is that you can never be "too cautious" Bundy. Good for you.
Tell the guys behind you why you are waiting and let them go ahead of you if they want to. I agree with you that in still air the turbulence will hang around from the point of rotation, from the departing aircraft, for longer. a slight crosswind will move it out of your path qiuckly.
I have not experienced it on the ground yet but have felt the bump after flying past behind and below other machines. My wife and I were given a real scare at New Tempe once. We were taking off on 28 when a dust devil approached from the right, directly next to the runway and it was moving into our take-off path. I was committed and could never stop before getting into it. Fortunately I could see it! When we hit it I was expecting all hell to break loose - and it did. Another fortunate thing is that generally dust devils are thermals and therefore take you away from the ground rather than the other way round. It was an ugly take-off but we were soon through it and everything returned to normal. I suspect if the whirlwind cannot be seen it could easily cause an accident on take-off or landing.
This picture shows wake turbulence vortices behind a landing airbus.
I too am a little lighter than the guys I generally fly with so I get in the air before their point of rotation if I can.
Good topic Bundy, allways worth considering.
Re: Wake turbulence...am I too cautious.
Posted: Sun Dec 18, 2011 8:19 pm
by ZS-NEL
Bundy, stuff them,- they must wait for you. You can always let them pass to take off first. If no wind wait longer to take off behind someone. Strong or moderate crosswind you can GO on their ARS.

Re: Wake turbulence...am I too cautious.
Posted: Mon Dec 19, 2011 9:30 am
by Blue Max
If you want to get airbourne in quicker succession, than the pilot infront of you should take of on a track more to the left of the runway and you follow on a track more to the right of the runway.( with consideration of a crosswind factor)
Re: Wake turbulence...am I too cautious.
Posted: Mon Dec 19, 2011 9:48 am
by Dish
Whats the hurry Bunds,,, wait until your comfortable, (should all have dissapated within two minutes) and then begin your take off roll... the oke behind you can wait, its that simple.... your lined up on the threshold, its your runway, you make the decision best for you, if you wait two mins so what. I may get a little miff if the oke in front of me is waiting for his temps to be correct or do run ups, (do that before you enter the runway) BUT if you have entered and are waiting for the "dust to settle" thats your perrogative. Perhaps make a radio call and just announce your intention to hold back a minute, but NEVER feel pressurised to roll before your comfy....
I remember once at CC Pococks in Barberton a Microlight called finals from a fair distance out and waiting on the threshold was a big beech 18 with two HUGE Radials burning fuel at a massive rate... the beech pilot was accomodating and even though burning S****loads of fuel waited for the Microlight to land and vacate...
In my eyes thats good airmanship, so long as your not messing around the lad behind you can hang on a little, goodness knows hes going to hang on behind you till hes comfortable??
Re: Wake turbulence...am I too cautious.
Posted: Mon Dec 19, 2011 5:24 pm
by Amick
I know there are guidelines based on waiting times for heavy, medium and light aircraft departing ahead of you but a common misconception is that flex's are 'light' in terms of wake turbulence. Because of the high angle of attack and low airspeed they produce a large amount of WT so you need to be careful.
Just my 2p worth.
Andrew
Re: Wake turbulence...am I too cautious.
Posted: Tue Dec 20, 2011 8:55 am
by Dobbs
Amick, totally agree, but also, because they have a low wing loading, they also feel the wake turbulence, or any other turbulence much more than say a rotor craft with it's very high wing loading.