Clive,
1. It is never prudent to sideslip down to the stall as an obvious spin wi
ll result. Final approach for a fully flapped approach of 1.3 stall (nomin
ally 60 Knots IAS) would be the prudent limit of a side slip airspeed. In
flight testing of mono and trigear, I side slip at 60 knots with a great bo
ot of rudder, but there are limitations applicable to any aircraft. Operat
ionally there is no requirement to excessively side slip an aircraft below
final approach speed.
2. No figures have been published on the added rate of descent from a side
slip.
3. The Gotchas' are:
Side slips approaching the stall will cause the receding wi
ng to stall quickly leading to a rapid roll and if aft stick and rudder are
held as the aircraft departs, a spin will result. UNLOAD FOR CONTROL IMME
DIATELY ON DEPARTURE FROM CONTROLLED FLIGHT!
Most aircraft in level flight near approach speed can blank
the tail plane if full rudder is applied. Again, at a safe altitude (3 mi
stakes high) one can get the full effect by simply slowing to about 70 knot
s, maintain level flight and add rudder until the stop. Allow the
speed to bleed and as more up elevator/stabilator is added the rudder/fin a
nd fuselage blanks one of the stabs. The blanked stab will lose its downfo
rce causing a rapid unloading of the aircraft and nose down pitch atti
tude ensues. In some aircraft it is quite violent and unexpected (RV-8s wi
ll bounce your head off the canopy). In a side slip using full rudder the
aircraft is somewhat unloaded as level flight is not being maintained and l
arge amounts of up elevator/stab are not being used to maintain level
flight so this unloading due to stab blanking is not experienced.
(When talking airspeed control, one must have his airspeed indicating syste
m verified and calibrated. Flight test and corrections to the airspeed are
necessary or you are talking apples to oranges. The Europa pitot/static t
ube on the XS is quite accurate when coupled to a properly indicating airsp
eed indicator normally, but calibration is still required.)
In my experience, side slips are used to correct errors in judgement. Norm
ally due to my lax attention to airspeed sometimes I am forced to bleed off
the excess on final if I don't want to float excessively. If at 70 Knots
trying to get to 60, one must understand that the Europa is very clean and
additional side slip does not give me a gratifying immediate response to be
ing too fast while holding glide path. Also, if the pattern is tight, side
slipping while trying to maintain a steeper than normal (2.5-3 degree) gli
de path, I find speed and altitude reduction is not comfortably fast in a s
ideslip. When going into a field that is shorter and the approach is guard
ed by high trees, I do side slip as the Europa will build speed quickly if
quickly unloaded after crossing the trees to establish an aimpoint near the
threshold (especially with a course propeller pitch). I find a side slip
at 60 with about half rudder displacement gives a comfortable 5 degree glid
e slope if memory serves. It allows me to cross the threshold at a very co
ntrollable speed to allow me to establish the landing attitude with gratify
ing results.
The stabilized approach and adherence to airspeed control is a far better a
nswer than side slipping with reckless abandon ( as I am sometimes forced i
nto due to lack of attention). Personally, 80KIAS on downwind abeam touchd
own. Apply full flaps, maintain 75 KIAS during the base leg/turn to final.
Bleed off airspeed to 60KIAS during the rollout to final with pitch and p
ower set. Maintain 60 KIAS until passing the field boundary. Reduce power
, and adjust aimpoint and allow for a slight speed reduction to cross the t
hreshold a few feet high at 55KIAS and the float is easy to control while s
ettling into the ground effect area. Float is about 500 feet on a hot day
over a hard surface.
Power control is essential. I teach that if you lower the nose (push over
to shorten the aimpoint) one must pull the power back immediately or an ins
tant 5 knots is gained. "If you push over, pull the power" seems to work w
ell with my clients. On short field landings, I slow to cross the fence st
abilized at 55KIAS with power on and bleed the rate of descent and speed to
cross the threshold with a decreasing speed and a controllable rate of des
cent to a firm touchdown. I only float a couple hundred feet max past the
threshold and am stopping in 600 to a 1000 feet on a hard surface. If forc
ed to a steep approach over trees or dikes, to the landing zone, I find slo
wing a bit more to 55 gives a sink that is significantly greater than 60KIA
S, which allows me to concentrate on a wings level approach, but the 55 kno
t steep near idle power approach also limits the amount of time to arrest t
he sink rate, and establish the flare. On grass strips with trees or power
lines I tend to hold 60 until over the lines, then reduce power, lower the
nose, sideslip a bit to drop in a bit quicker and use the extra speed to a
rrest the steep descent which bleeds the speed to 55 knots anyway and then
go for the landing attitude.
When I really screw the approach I just go around and get my stuff together
. If I've never landed on a field before or the conditions are not favorab
le for mistakes, I tend to do a very low approach (drag the field in a slow
flight) sizing up the landing zone and wind conditions before making my ap
proach and landing for real. I look for a point where a safe go around can
be accomplished if I screw the approach to landing. That makes the final
a very comfortable skilled looking landing and uneventful roll out.
Best Regards,
Bud Yerly
-----Original Message-----
From: owner-europa-list-server@matronics.com <owner-europa-list-server@matr
onics.com> On Behalf Of clivesutton
Sent: Tuesday, February 16, 2021 4:18 AM
Subject: Europa-List: Side-slipping the Europa?
mailto:clive.maf@googlemail.com>>
I use side-slipping occasionally on final approaches/flapped. It can be a
very useful way to lose altitude more quickly than usual.
But I can't find anything in the Mono owners manual on best practice/limits
for side-slipping - can anyone enlighten me? Specifically:
1) Could/should one side-slip right down to stall+5kts?
2) Are there side-slip performance differences between Mono and Tri-Gear?
3) Are there any side-slipping 'gotchas' that i should be aware of?
Clive Sutton
G-YETI
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