Wing drop

[Lister Noble]

Flying in the L4 Cub this morning near the East coast,around 600 ft passing over a friends farm then crossed over a small caravan park with a tarmac surface .
Sunny, 10-15 kt ENE wind but quite bumpy .
Everything as it should be re speed,attitude etc and then a massive wing drop on the port side,at least 45 degrees maybe more.
I immediately corrected with aileron and was OK, but quite a shock.

I am aware of thermals effects over plough,grass,estuary changes but this was something else.

Could this have been a thermal effect on one side of the aircraft?
Lister

[JP1]

Yes...

I remember when I used to glide from RAE Farnborough, over the diamonds (the concrete area around some of the hangers) I was almost thrown out of the cockpit of the K-8.

My hour was up so I pushed the nose down to lose height, probably was doing 65 Knots (that was fast for her), the thermal was so tight that I punched through it in a fraction of a second. Hence the rapid ascent followd by a rapid descend and my arse leaving the seat.

I guess either one wing hit a thermal or the other the sink from a thermal and hence your roll.

[BartV]

Yes, I had them also even correction input with aileron did not worked directly, it took another second or so, that was at least 45degrees while I was in level flight before, could be some wind shear created by the ground shape (roof of buildings etc...)

[Zulu Alpha]

Was a good day for thermals today. Even the Laser was buffeted by thermals at 600ft, so a Cub with low wing loading would be bounce about a lot.

ZA

[Them thar hills]

Lister
How do you know it wasn't the other wing that rose ??!
Thermals etc.
(just a thought)
Regards
tth

[Lister Noble]

Thanks for the replies.
I have been thinking,it was such a natural reaction to lift the wing with the stick and it was OK because the aircraft was not stalled.
Although if one was in a stall and the wing suddenly dropped,it could be natural in the event to use the stick rather than the rudder to lift the wing,which is where the danger of a spin lurks,often with no height to recover!
Maybe time for me to get some more stall/spin training?
Lister:)

[BartV]

Just make sure you got the ball centered, if I use ailerons, I always use rudder so should you!!!

[Gertrude the Wombat]

Could this have been a thermal effect on one side of the aircraft?

Yes.

One very sunny day the thermals from the tarmac runway upset me sufficiently that I landed on the parallel grass runway off the third approach.

[airborne_artist]

I remember quite a pronounced wing drop from the thermals rising off the roof of the Vauxhall works soon after taking off from Luton's 26. Probably August, so the sun would be about the same strength as now.

[Mariner9]

Loads of thermals yesterday en route to/from N Weald from Wales - we hit several at 500'/minute and 1 at 600'/minute. Put one wing in that and it'll rise 10' per second...

[Arclite01]

Hey Lister

I used to regularly use the thermals to help me climb the Cub on hot days - especially 2 up with full fuel - I was amazed just how effective they were in helping me climb away. And when you get near to cloudbase you can throttle right back (with carb heat out) and actually still seee the altimeter winding up the altitude.........

But I was a glider pilot before I was a PPL so that helped me................ :-)

A trip to Tibenham for a couple of trips in the motorglider will really open your eyes to the benefits of thermals in a safe environment............

With regard to your other question - the Cub out of balance, in a thermal will drop a wing and you need to have this demonstrated to you. A competant instructor will demo this at height and you will see that it can indeed be (I hesitate to use the word vicious but) pronounced or surprising............. if you are low the results are obvious, also be aware of the torque effect of the engine/prop, so...... nose high, light AUW, low power settings or high power settings (torque+direction), out of balance, plus thermic instability may well produce a pronounced wing drop. Recovery is standard but maybe get Linda or Gerry to demo it for you - once you've seen it - you'll recognise its onset and recovery is standard as you have been taught (power plus control column centrally forward and rudder neutral).

Nothing to be scared of but aware is good

Regards from NZ by the way, good to see you still enjoying yourself.

Arc

[Andy_RR]

...but did you know there was once a glider version of the Cub airframe? I didn't but according to the Evergreen Avaition museum in McMinnville, Oregon their Cub specimen was actually first built as a glider - i.e. sans engine! :eek:

[The Flying Pram]

This is why I don't fly my Flash II winged microlight during the day - not only would a substantial wing drop (or lift) be in order, but by the time it had sorted it self out I would probably be traveling on a reciprocal heading!!

[Lister Noble]

Hello Arc,
Good to hear from you,and yes I am using the Cub a lot.
Thanks for the advice,I know some bods at Tibbenham so will approach them after my hols.
We are taking the car by ferry up to the Russian border with Norway,then driving back through Norway to Bergen then home ,it should be an interesting trip.
Anyway enough of that,I'm so thankful I got your share in the Cub,it is very cost effective and most enjoyable flying, and there is quite a waiting list now!
Best wishes to you and family
Lister:)

[Arclite01]

Hi Lister

Depart NZ for Canada on 8th June (after the All Blacks game in Wellington on the 7th !!!)

So more adventures :-)

Thanks for the good wishes

Arc

[9v-SKA]

During my last solo cross country before my PPL flight test I had quite a bit of wing drop. But I was flying over a mountainous area. Quite scary being in the tiny Jabiru with everything going well, suddenly the right wing just dropped.

My first instincts were to correct with alieron. And I came out fine but quite shaken.