Primarily for general aviation discussion, but other aviation topics are also welcome.
By ozplane
FLYER Club Member  FLYER Club Member
#1612789
Bimbling along in the Wonderplane yesterday there seemed to be quite a lot of thermic activity. It has a fairly high wing loading of about 14 lbs/sq ft and does "punch" through the bumps quite well. However I know nothing of flex wing microlights and I wonder how they cope with these conditions with what I suppose are much lighter wing loadings?
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By defcribed
#1612816
I found Saturday much bumpier than Sunday.

Actually it wasn't 'bumpy' per se - nothing you could really describe as turbulence - just not smooth and more work to hold an accurate heading and altitude. Not conducive to trimming for hands-off flying, and the sort of conditions that make me wish the aeroplane had an autopilot.
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By Josh
#1612853
Thermals were pretty punchy on Sunday I thought - around 4-500 fpm in places below 2000 ft. Certainly no chance of hands-off flying and made accurate flying a bit of a challenge. Unlike defcribed though, it was a joy to have all the automatics off ;)
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By Genghis the Engineer
FLYER Club Member  FLYER Club Member
#1612913
ozplane wrote:Bimbling along in the Wonderplane yesterday there seemed to be quite a lot of thermic activity. It has a fairly high wing loading of about 14 lbs/sq ft and does "punch" through the bumps quite well. However I know nothing of flex wing microlights and I wonder how they cope with these conditions with what I suppose are much lighter wing loadings?


At first approximation gust response is a function of speed over wing loading. So the Flexwing loses on wing loading (low) but gains on speed (slow). However, they have an added achiles heel, which is that having no rudder they have to have high directional stability (provided primarily by wing sweep) that tends to cause significant yawing excursions in turbulence.

They compensate somewhat however by pendular stability - basically the CG is a long way below the wing, and pilots are trained to hold onto the bar and damp out the motion using the weight of the trike. It works, but you end up with somewhat tired arms (even more tired if you're daft enough to actually fight the motion, rather than gently easing it steadily back to wings level). But also anybody "in the know" never flies a flexwing lightweight in summer thermals - load the tank up full, put a big "boss bag" full of water in the back seat if you haven't got a passenger, and also trim fast - as whilst the "g" response to vertical gusts will go up a bit, faster reduces the directional stability and thus the yawing (and through secondary effect, rolling) excursions a bit and makes the flying experience rather less comfortable.

But, executive summary - yes, flying flexwings on thermic summer days is somewhat hard work compared to 3-axis microlights or light aeroplanes.

G
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By MichaelP
FLYER Club Member  FLYER Club Member
#1612919
It was really uncomfortable in G APNZ flying down the Lea Valley on my commute from Little Gransden back to Redhill.

Leather helmet, open cockpit, no radio, no transponder, the little aeroplane bounced over on one wing and then the other... A little scary as you can almost touch the wingtips.
Over the Isle of Dogs, and slide home between Biggin and Kenley.
I can still remember the turbulence in that Turbulent clearly. Not a pleasant flight.
By Stu B
#1613086
A British friend's wife refused ever to fly with him again after encountering turbulence flying in New Zealand during a holiday. They do seem prone to some pretty severe events down there.
A NZ pilot friend insists his Bolkow Junior was once flipped inverted in turbulence - IN PITCH!