Crosswind and 3 point takeoffs

[Bryan Cotton]

A while back I ran out of rudder when up on the mains during a takeoff roll. Quite the adventure. I've done some thinking and reading, and decided to try 3 point takeoffs with one notch of flaps. The airplane leaps off the ground pretty quickly and I didn't even get any shimmy. With the tailwheel planted, lots of directional control. With 55 hours of Waiex time under my belt the worse sight picture was not an issue.

So for you Sonex tailwheel guys who fly in crosswind, is this what you do? Or any techniques to share?

[GraemeSmith]

Legacy SONEX - I roll a LOT of aileron into wind on a X-Wind Take off to put weight on the upwind main and - if the toe in is set correctly - it helps track the nose downwind (though the plane stays on the centerline).

I've never run out of rudder on the take off - only the landing which I demonstrated up to 19 knots square - at which point the Sonex 6" hard rubber tailwheel started to lose adhesion on a dry pavement.

I don't routinely set any flaps on take off - you might pop off but then you don't accelerate so well - which might be important if there is an obstacle. I have however experimented with F E Pott's bush/rough field trick of getting rolling, pulling flaps 10 to get you out the dirt and then EASING it off to get the plane accelerating without sinking back onto the ground. It DOES work - but not something I would make a habit of doing in a big X-Wind.

I have no Waiex experience but I have heard that "real world" the Waiex is possibly slightly less crosswind capable than the T tail - despite the factory saying there is no difference.

[Bryan Cotton]

I don't routinely set and flaps on take off - you might pop off but then you don't accelerate so well - which might be important if there is an obstacle. I have however experimented with F E Pott's bush/rough field trick of getting rolling, pulling flaps 10 to get you out the dirt and then EASING it off to get the plane accelerating without sinking back onto the ground. It DOES work - but not something I would make a habit of doing in a big X-Wind.

Graeme,
I have the small flaps and with one notch it seems to climb pretty well. I have not done takeoff performance curves with flaps yet. Once I've popped off the ground I am nosing back over to keep it in ground effect, get it coordinated and crabbed into the wind, and then accelerate as normal. I think the key thing I like about it is the tailwheel is the last thing to leave the ground. Even if this technique compromises the performance to clear a 50' obstacle by some amount, the benefit of not running out of rudder and staying in control seems like a good tradeoff.

Next month I'm headed XC and I don't want to be hobbled by a low crosswind limit.

Thanks for the feedback!

[GordonTurner]

Gusts encountered on takeoff notwithstanding, the rudder and other controls become more effective as speed builds. Leaving the tailwheel grounded just a little bit longer, the little bit being defined by the strength of the crosswind, will allow the rudder to be effective when the tail comes up. If the crosswind is strong enough, the rudder effective speed may be higher than liftoff. The ailerons are also critical for strong crosswinds

[mike.smith]

99% of the time I take off 3-point, with 1 notch of flaps, whether there is a crosswind or not. Everything is a trade-off, but this works best for me in pretty much any situation you can think of. The exception is grass runways, where I start 3-point, but quickly try to get the tail wheel a few inches off the ground. After about 450 hours without a notch of flaps, the last 100+ hours have been with 1 notch, and there are, again, very few instances where I won't do that.

A Sonex with the wheel on the ground is in take-off attitude, so I get off the ground quickly. That's also what the factory taught when they were doing flight training. Taking off on the mains is not in take-off attitude, so it takes a couple of hundred feet more to get airborne. since you need more air over the wings.

YMMV...

[Bryan Cotton]

We had 8-9 kts more or less direct crosswind today. Much more control margins as compared to rolling on the mains.

[Bryan Cotton]

[MichaelFarley56]

We had 8-9 kts more or less direct crosswind today. Much more control margins as compared to rolling on the mains.

I have found some luck on crosswind landings by landing flaps up but still landing in a 3 point attitude. The only difference is you need to be below glide slope on final approach as you won’t have as much drag as normal.

[Bryan Cotton]

I have center (sport trainer) controls built to plans. The flap stop angle is built to let you pull smoothly from the first notch to full flap - but on the ground you can't select the first notch. Gravity pulls the flaps to full. For takeoffs, we had been using a leg to hold it in place during the takeoff roll. Works, but not the best. Also not possible when soloing from the right seat. So, I made a bungee to counteract the weight.

As you can see, it weighs nothing. I didn't weigh the hole I drilled in the flap stop.


The bungee is threaded through the hole and knotted. The loop around the flap handle is held by a couple of hog rings and covered with heat shrink.