Resistance to Turbulence

[tropical]

Sorry, no such thing as VG's making a plane "resistant to turbulence".

[CO_Skymaster]

Another case of wishful thinking.

Thanks for the information,

Karl

[Roger]

Every female in my family wears the electronic wrist, motion sickness devices, and they swear by them. Get your wife one, tell her you put VG's on the plane and it eliminates motion sickness, and see what happens A little placebo VG flying with the wristbands may do the job.

[jchronic]

On our marine mammal surveys, we frequently circle in place for 20-30 mins at a time at 30 degree bank angles, so in light/no wind situations we regularly encounter our own wake. Last year, using a 'straight' 337, we got some pretty good jolts after several circles. This year we've been using a 336 with a Robertson (Sierra) STOL kit and the whole crew seems to think the wake turbulence jolts are much milder than last year (in the 337).

Strictly anecdotal and I wouldn't attempt to explain it aerodynamically, but thought I'd offer the info. In any case, I seriously doubt it'd be worth the cost of a conversion for whatever improvement there might be in the ride.
Joe C.

[tropical]

Originally Posted by jchronic

On our marine mammal surveys, we frequently circle in place for 20-30 mins at a time at 30 degree bank angles, so in light/no wind situations we regularly encounter our own wake. Last year, using a 'straight' 337, we got some pretty good jolts after several circles. This year we've been using a 336 with a Robertson (Sierra) STOL kit and the whole crew seems to think the wake turbulence jolts are much milder than last year (in the 337).

Strictly anecdotal and I wouldn't attempt to explain it aerodynamically, but thought I'd offer the info. In any case, I seriously doubt it'd be worth the cost of a conversion for whatever improvement there might be in the ride.
Joe C.

While you are circling do you have any flaps down? Doesn't the Robertson kit droop the ailerons slightly when flaps are extended?

[jchronic]

Last year with the 337, I arbitrarily put down 1/3 flaps as soon as we started the circle. Depending on the wind and sun angle, the circles can become ellipses and the bank angles get up to 45 degrees to get the pictures that the scientists want, and the focus gets to be on tracking the surface 'targets' rather than fine-tuning the airplane configuration.

With the STOL 336, I've found I can delay or even omit the flap extension, depending on how aggressive the maneuvering needs to be to get the data and photos they want. One thing we did notice, in straight and level flight, the airplane flies in a pronounced nose-up attitude, to where vis over the nose is almost marginal. I should note that we fly the survey tracks at 100mph GS; obviously it's better at more normal cruise speeds - but not much.

As I noted before, I can't imagine the $$ involved in a conversion would be cost effective strictly for ride improvement, or even for what we do; this just happens to be the airplane we were able to lease this year.

I can't answer the question on whether the ailerons are supposed to droop with the Robertson kit. Ours don't, and the airplane logbook shows that it's a Robertson conversion.

Joe C.

[John Hoffman]

Yep - the Robertson is interconnected with the ailerons so that as you add flaps the ailerons come down a bit to increase lift. Robertson also includes stall fences, leading edge cuffs and drooped wing tip caps - at least on my plane. Guess all the reconfiguration gives the STOL performance your looking for, cant say what it does for turbulence other than allowing you to fly real slow.