Waiex cross-wind component comments [Waiexplans, 2.8.13]

[sonexpilot]

Subject: Sonex factory Waiex cross-wind component comments
[Waiexplans, 2.8.13] [Waiex]

Hello again Sonextalk and Waiexplans groups-

Sonex has been following the discussion on the cross-wind capabilities of
the Tail Dragger Waiex and know it's again time to provide some comments.

The Sonex factory experience and opinion is almost identical to the
experience posted recently by Waiex builder and pilot Bill Hebestreit:
--------------------------------------------------------------
Re: cross wind component
Wed Jan 23, 2013 12:33 pm
Posted By: dogmop2

I guess it is time to put my oar in the water on this subject. I have the
drum brakes and the basic problem is that the wheel flange that locates the
drum is not concentric with the bearing bore. I made up a lathe fixture and
turned the wheels so that the drums were centered and have loaned the
fixture to several other Sonex builders. I agree with Kerry that
differential brakes are not necessary. My field is in a narrow valley at
2600 feet altitude surrounded by 6000 foot mountains. We have three
windsocks. One at each end and one in the middle. On summer afternoons all
three windsocks will be pointing in different directions.

I have not had any problems with the Waiex but I always make 3 point
landings so the airplane has really stopped flying when I touch down. I made
a wheel landing once and did not feel comfortable. I normally use full flaps
and have a sink rate of 700 FPM. There is plenty of pitch control available
to flare and I add about 100 RPM when I am about 5 feet high to feather out
the flare. At this point you are in ground effect and the plane is very
stable because cross winds do not seem to come that close to the ground. The
first turn off is about 800 feet down the runway and I usually make it
without using brakes because my airspeed is close to stall at touchdown.

For takeoff I start with full down trim. My weight is usually about 1000
pounds and I am near the aft CG. This probably keeps the tail on the ground
because steering is OK. I do not hold any stick pressure. I just open the
throttle and wait until it flies and then start adding up trim when I have
accelerated to about 80MPH. Right after liftoff I aim my heading about 30
degrees to the right of the runway. There is a lake in front of me so by
operating offside I can turn and land downwind if there is a problem.

I helped build and have flown a Thorp. It has differential brakes. Due to
the wide canopy and fairly short coupled tail there is a unique
characteristic with this design. There is a 5 knot window on takeoff and
landing where the tail wheel is off the ground but the rudder is not
effective because the airflow is blocked by the canopy. In this case the
differential braking is a must have item. But I don't see that the Waiex
would have this condition. The only concern
I have with hydraulic brakes is the difficult accessibility to the lower
cockpit after the plane is finished.

Bill Hebestreit N33YX AeroVee
==========================
This topic comes up every now and then and seems to be fed by the same
people, one of whom we just found has installed differential brakes and a
full swivel tailwheel. This is counter to the Sonex philosophy of a simple,
light-weight system and at the end of the day can wreak havoc on the ground
handling qualities of a Sonex Aircraft by introducing the vagaries of a
full-swivel, brake-and-spring-steered tailwheel system and all the piloting
challenges those systems present.

There are a number of factors here that must be considered, and only one is
the aircraft design. As designed, the Waiex has the same cross-wind
capability as the Sonex. That is as far as a direct comparisons as we can
go, as each airplane is hand built by a wide variety of builders with
varying skills, levels of workmanship, and attention to detail. If an
aircraft is built which isn’t rigged properly, doesn’t have the correct gear
geometry, doesn’t have the tailwheel properly aligned with the rudder, has
an offset thrust angle, has an incorrect tail incidence, or any combination
of the above, you can have an aircraft that does not handle as designed. To
what degree it does not handle correctly is hard to say, but certainly these
items individually or any combination of them can impact handling.

The next unknown is pilot skill. The Sonex factory taildragger aircraft
family is exclusively landed by our pilots in a full stall configuration.
Our approach feels like you can get out and walk next to the airplane.
Entering ground effect feels like hitting a pillow of air with full flaps
and the aircraft belly exposed. There is very little to no energy left as
the aircraft touches down and stops.

There will always be people with differing results. We ask that you have
your own experience, and try not to anticipate problems based on the
experiences of others. We also ask respectfully that all seek flying
guidance from the experts at the factory who regularly fly and maintain a
version of every airframe we sell.

As always, please feel free to contact any member of the Sonex Team at the
numbers or e-mail below with any questions or Comments.

Regards,
-Sonex Aircraft, LLC
--
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