Thank you Bob for the detailed post. I am flying a Ventus C with airbrake and flap combination.
Dan G
On Saturday, October 12, 2013 10:19:29 PM UTC-4, Bob Whelan wrote:
On 10/12/2013 5:56 PM, wrote:

I wonder how other pilots of flapped ships are using their flaps. I don't

use any flap till I am aligned with the runway on final approach. Don't

like the sluggish aileron control and the forward stick pressure required

on the dreaded base to final turn. I switch to positive flap on final. Any

comments ? Dan G





Ummm...additional context would be helpful, he ship type; synopsis of your

experience (ships, hours), both overall and in the ship.



That said, I transitioned (1975) into a 15-meter glass, large deflection

landing flapped only (no spoilers) ship (Concept 70) with 128 prior total

hours, entirely in 2-33s, 2-22s and 1-26s; zero power experience.



I wanted a flatter gliding 1-26...as in I didn't want to give up the short

off-field-landing capabilities of a l-26, and considered large deflection

landing flaps just the ticket. Never saw reason to change my opinion in that

regard...flying the C-70 for 48 hours, an HP-14 for 196 hours and a Zuni for

2065 hours. Never had any 2-seat flap training (decades' later exposure to an

L-13 and an IS-28 were irrelevant in "flap use/training" terms in my opinion).



I considered myself a raw beginner, and, I considered the performance increase

step as significant as the change from spoilers to large deflection flaps. My

total knowledge of what to expect from flaps had come from reading ("Soaring"

magazine, various college textbooks).



My 1st-flight initial plan was to use no more than 30-degrees of landing flap,

in order to reduce exposure to "significant pitch changes", a plan based

entirely on book knowledge...and a plan discarded on final approach when it

became apparent an overshoot was in the cards if I didn't come up with lots

more drag, Real Soon Now. Eventually touched down about halfway down a 4,000'

strip, after using all 90-degrees of the flaps, and having zero practical

issues with so doing. I simply flew indicated airspeed (just like with

spoilers), and the pitch attitude fell out in the wash. Later - when I

eventually flew 1-34s and 2-32s (both ships with Vne-limiting dive brakes) -

it became apparent that Joe Pilot (i.e. me) couldn't tell the difference

between pitch changes due to flap pitching moment changes and (lots of) drag:

both require forward stick to maintain airspeed, and in the single-seat

gliders I've flown, stick pitch forces are minuscule...well except for

Schweizers at above trimmed speeds! :-)



As to your wondering "...how other pilots of flapped ships are using their

flaps," I generally used mine just like spoilers. Just as my goal - assuming I

wasn't practicing some specific landing technique - with spoilered ships was

to fly patterns allowing steady-state use of 50% of the spoilers, so it was

with landing flaps. By "50%" I mean I sought to fly my "routine patterns" in

the middle of my ship's descent cone (which isn't necessarily 50% flap

deflection. This conceptual goal was routinely modified for the HP-14, for

reasons noted 4 paragraphs below...but the modifications had zero to do with

flaps per-se, and 100% to do with how that ship's flaps were *actuated*.)



Coupla ship-specific notes here - since you note you're less than

happy/comfortable with the need for forward stick pressure and what seems to

you like sluggish aileron control with flap in...

- the C-70 had "PIK-20-like" rack and pinion actuated flaps, driven by a

multi-turn crank;

- my HP-14 had hydraulicly-actuated flaps, 5 pumps for full deflection;

- my Zuni has flaps actuated by pulling back on a pivoting handle (very little

mechanical advantage) through an arc of perhaps 45-degrees.



In none of those ships are stick pitch forces significant, flaps up or flaps

down. I never felt the C-70 or the Zuni sluggish in roll, regardless of flap

position. The HP *was* a slow roller, regardless of flap position (some HP-14s

have had the outer 3' of flaps turned into ailerons to address this

condition). Both HP and Zuni (side stick) have relatively high (in single-seat

glider terms) aileron forces, IMO, regardless of flap position.



Because my home field - shared with power traffic - has the glider pattern

inside the power pattern, enlarging the pattern to accommodate the HP-14's

slow-rolling, heavy-aileroned, tendencies wasn't an option, so I compensated

by flying a continuously turning pattern, varying the bank angle as required

while performing the 180 from downwind to final...it was a no-brainer and

physically-easier to do so than to horse on the stick for the sake of "a

pretty, textbook, rectangular pattern." Navy pilots do the same thing, though

for different reasons.



Because the HP's flaps were essentially a "one-shot" (a consequence of how its

hydraulic system functioned and was installed), I generally put in one pump on

downwind (to verify they were going to work), a 2nd pump "somewhere on base"

(to bring on sufficient drag to actually begin descending from flap drag), a

3rd pump on longish final, and the last two pumps on short final (the ship

landed most gracefully/easily/shortly with full flaps). With full flaps, that

ship's fuselage angle was ~45-degrees nose down at approach speed...great

view, trivially easy to spot your roundout point, rock stable.



The Zuni's flaps are weenie, compared to the HP-14's, and in it I fly a

rectangular pattern and I really do generally try for the center of the

descent cone all the way down (aka a stabilized descent path), though I

usually wind up biasing that toward the upper half of the cone, since its 50%

approach path is so shallow (compared to the HP's and my "comfort zone"). In

the absence of strong crosswinds, I usually have full flap in on that ship

several hundred horizontal yards short of my roundout point; its fuselage

angle at pattern speeds is probably less than 30-degrees nose down.



Based on your ship, YMMV, of course. FWIW, assuming your ship has sufficient

drag to get you down where you're aiming at when you delay putting in any flap

until final approach, "More power to you!" Do what works.



Personally, If I flew a glider that could land vertically, I wouldn't use my

drag device until I was overhead my intended touchdown point. Why would I want

to? That's by way of suggesting that - assuming so doing doesn't introduce any

site-specific safety issues - "doing what works for you and your ship" is a

perfectly valid methodology for Joe Pilot to adopt. The point, after all, is

to be able to land consistently and safely. "The textbook pattern" is simply a

means to that end. (Flame suit on...)



As to your comment "Don't like the sluggish aileron control (with large

deflection flaps)...", flying the HP-14 with full flaps involved an

interesting (to me) effect (several, actually, but this post is long enough

already!). I was used to, as a glider pilot, seeing and "rating" my aileron

effects with the fuselage more or less horizontal. Pitched significantly nose

low, the visual - and actual - aileron effect on your path over the ground

differs, simply due to geometry. (Imagine descending vertically, rolling

90-degrees, and your new path relative to the ground.) In broad brush terms,

*the horizontal change* induced by aileron input to your path over the ground

reduces as your pitch angle increases, and the effect Joe Pilot perceives is

that his ailerons are becoming less and less effective, since we usually use

aileron to change our path over the ground...or at least that's the way my

thermalling glider brain thinks of aileron use. Aerobatic-rated pilots

probably know well what I'm talking about...



Anyhow...enjoy your landing flaps!



Bob W.