Any views (anyone) of the differences of stall and/or spin behaviour in ground
effect (I.e. within one-wing span height of the ground)?
Either theoretical or actual.
Duncan McF
> On 16 February 2021 at 15:28 Bud Yerly <budyerly@msn.com> wrote:
>
>
> Clive,
>
> 1. It is never prudent to sideslip down to the stall as an obvious spin
will result. Final approach for a fully flapped approach of 1.3 stall
(nominally
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 boot of
rudder,
but there are limitations applicable to any aircraft. Operationally 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
> sideslip.
>
> 3. The Gotchas' are:
>
> Side slips approaching the stall will cause the receding
wing 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
IMMEDIATELY
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 mistakes
high) one can get the full effect by simply slowing to about 70 knots, 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 and fuselage
blanks one of the stabs. The blanked stab will lose its downforce causing a
rapid unloading of the aircraft and nose down pitch attitude ensues. In
some aircraft it is quite violent and unexpected (RV-8s will 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 large 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
> system
verified and calibrated. Flight test and corrections to the airspeed are
necessary or you are talking apples to oranges. The Europa pitot/static tube
on the XS is quite accurate when coupled to a properly indicating airspeed
indicator
normally, but calibration is still required.)
>
>
>
> In my experience, side slips are used to correct errors in judgement.
> Normally
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 being 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) glide path, I find
speed and altitude reduction is not comfortably fast in a sideslip. When going
into a field that is shorter and the approach is guarded 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 glide slope i
f memory serves. It allows me to cross the threshold at a very controllable
speed
to allow me to establish the landing attitude with gratifying results.
>
>
>
> The stabilized approach and adherence to airspeed control is a far better
answer than side slipping with reckless abandon ( as I am sometimes forced into
due to lack of attention). Personally, 80KIAS on downwind abeam touchdown.
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 power set.
Maintain 60 KIAS until passing the field boundary. Reduce power, and adjust
aimpoint and allow for a slight speed reduction to cross the threshold a few
feet
high at 55KIAS and the float is easy to control while settling 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 instant
5 knots is gained. "If you push over, pull the power" seems to work well
with my clients. On short field landings, I slow to cross the fence stabilized
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 descent 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 forced to a steep approach
over trees or dikes, to the landing zone, I find slowing a bit more to 55
gives a sink that is significantly greater than 60KIAS, which allows me to
concentrate
on a wings level approach, but the 55 knot steep near idle power approach
also limits the amount of time to arrest the 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 arrest 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 favorable
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 approach
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@matronics.com>
On Behalf Of clivesutton
> Sent: Tuesday, February 16, 2021 4:18 AM
> To: europa-list@matronics.com
> Subject: Europa-List: Side-slipping the Europa?
>
>
>
>
>
>
> 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
>
>
>
>
>
>
>
>
>
> Read this topic online here:
>
>
>
>
> https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fforums.matronics.com%2Fviewtopic.php%3Fp%3D500721%23500721&data=04%7C01%7C%7C84e533f065974e3931d708d8d25c4ccd%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637490641151030538%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=oBzCUM8Inbe%2BPC58uq%2B3jScWrfJoxLVufqk2wrgF0Rc%3D&reserved=0
https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fforums.matronics.com%2Fviewtopic.php%3Fp%3D500721%23500721&data=04%7C01%7C%7C84e533f065974e3931d708d8d25c4ccd%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637490641151030538%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=oBzCUM8Inbe%2BPC58uq%2B3jScWrfJoxLVufqk2wrgF0Rc%3D&reserved=0
>
>
>
>
>
>
>
>
>
>
>
>
>
> - The Europa-List Email Forum -
>
> -->
> https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.matronics.com%2FNavigator%3FEuropa-List&data=04%7C01%7C%7C84e533f065974e3931d708d8d25c4ccd%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637490641151030538%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=56a0uH04SXaCNvK6D8bFLd3Crg9fv%2BEOqg%2B9PM6n0PE%3D&reserved=0
>
> https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.matronics.com%2FNavigator%3FEuropa-List&data=04%7C01%7C%7C84e533f065974e3931d708d8d25c4ccd%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637490641151030538%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=56a0uH04SXaCNvK6D8bFLd3Crg9fv%2BEOqg%2B9PM6n0PE%3D&reserved=0
>
> - MATRONICS WEB FORUMS -
>
> -->
> https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fforums.matronics.com%2F&data=04%7C01%7C%7C84e533f065974e3931d708d8d25c4ccd%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637490641151030538%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=QxBCFyXSrAeiWkXLU81om5sHLz5o%2B4yxfBvkHoog3FE%3D&reserved=0
https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fforums.matronics.com%2F&data=04%7C01%7C%7C84e533f065974e3931d708d8d25c4ccd%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637490641151030538%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=QxBCFyXSrAeiWkXLU81om5sHLz5o%2B4yxfBvkHoog3FE%3D&reserved=0
>
> - NEW MATRONICS LIST WIKI -
>
> -->
> https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwiki.matronics.com%2F&data=04%7C01%7C%7C84e533f065974e3931d708d8d25c4ccd%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637490641151030538%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=wvvFgPj29ErlAi6y4i0rBkXjcLMHk9zLFbaWGWVR08g%3D&reserved=0
https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwiki.matronics.com%2F&data=04%7C01%7C%7C84e533f065974e3931d708d8d25c4ccd%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637490641151030538%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=wvvFgPj29ErlAi6y4i0rBkXjcLMHk9zLFbaWGWVR08g%3D&reserved=0
>
> - List Contribution Web Site -
>
>
> -Matt Dralle, List Admin.
>
> -->
> https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.matronics.com%2Fcontribution&data=04%7C01%7C%7C84e533f065974e3931d708d8d25c4ccd%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637490641151030538%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata37wiklW59FtG%2FKGHAeC2BFWk4k3KVN9K6gYbLvsfA%3D&reserved=0
>
> https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.matronics.com%2Fcontribution&data=04%7C01%7C%7C84e533f065974e3931d708d8d25c4ccd%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637490641151030538%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata37wiklW59FtG%2FKGHAeC2BFWk4k3KVN9K6gYbLvsfA%3D&reserved=0
>
>
>
>
>
>
>
|