On 1/5/2011 12:53 AM, Doug Greenwell wrote:
At 02:13 05 January 2011, AGL wrote:

Has anyone tried some flaps in an integrated flap machine (which
reduces stall speed) to see if the wallowing goes away?

Unfortunately, my trailer is in a snowbank.

That's a useful comment: the aerodynamic modelling I did suggests that
the lateral control problems on tow should be different (worse) than those
in a typical stall, because the wing is stalling at the tips rather than
the root.

No-one has yet admitted to actually stalling or dropping a wing on tow -
so the effect seems to be annoying rather than dangerous.

Flaps should (theoretically) improve matters by (a) reducing stall speed
and (b) shifting the spanwise lift distribution inboard and unloading the
tips. However, if the flaps are integrated with the ailerons then the
associated aileron droop would counteract (b).

My ASH 26E has the flaps and ailerons moving in unison in the 1,2, and 3
"cruise" positions; flap 4 (thermal) moves the flaps down a bit more
than the ailerons, so there is some washout in the wing. That might make
it handle better during a slow tow than it otherwise would. I've never
had a slow tow, so I can't say. If I ever take another tow, I'll compare
flap 3 and 4 with the tow plane going "slow".

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)
- "