My experience and available facts concur 100% with Ed's comments.
WRB
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On Mar 28, 2010, at 22:29, Ed Burkhead wrote:
Hartmut wrote:
> If Fred Weick expected half the fleet being sold with
> rudder pedals, why would a designer go through so
> much work and develop the complicated and then so
> easy mechanism for the two control plane?
> The twin rudders were a result of the developments for
> the two control, as is the canted engine mount. All to
> assure that the aircraft flies straight even without the
> input of the rudders. Really, if I expect half of my
> customers wanting to have a three control aircraft,
> why not stick with the single rudder tail of the prototype,
> the model 310 ?
Hartmut, I suspect that’s not quite right. Fred wanted to develop a
plane that was well behaved at all times.
Putting the vertical stabilizers outside the slipstream keeps the
slipstream from causing trim changes when going from idle to full
power. That’s because the slipstream spirals around the plane rather
than flowing back linearly. I don’t know how much spiraling effect
there is, but it’s enough, pushing on the side of a single vertical
stabilizer and rudder to require rudder input.
Whether there are rudder pedals or not, Fred didn’t want that change
in behavior.
Hartmut wrote:
> However, from what I read, the airplane was designed
> around eliminating pilot errors.
May I suggest that his concept was that the plane should not cause
problems due to its faulty or lazy design.
Hartmut wrote:
> One is the unintentional stall that is mitigated with the
> elevator limitation, the other is cross controlled stalls by
> making the plane a two control aircraft.
As far as I know, the certification against spinning was still in
effect when rudder pedals were installed. I tried stalls with my
rudders FULLY cross-controlled, with full right aileron and full left
rudder (the worse condition). It did make the gyrations more lively,
for sure. But it did not break into an uncontrollable regime. I
tested this up to just a smidgeon below full power, at about 1320
pounds albeit with elevator limited to 9˚ up travel (so I can’t
generalize too far).
Hartmut wrote:
> Rudder pedals are against this idea.
I only report what he said to me. My memory is not perfect, but that
conversation did tend to burn into my mind because of the surprise and
insight of what he said.
Hartmut wrote:
> I read that in the thirties most airfields were just that –
> fields. You could always land into the wind, thus
> eliminating the need for landing in cross winds and hence
> the need for rudder pedals.
There were plenty of runways around in the very late ‘30s. Any
designer who built a plane incapable of handling crosswinds on a
limited width runway would have been designing a very dangerous
aircraft. Not Fred Weick!
Hartmut wrote:
> Maybe it was the other way around. The marketing
> department pushing for rudder pedals to give the folks
> what they were used to.
No, that’s not what he said and the conversation was clear. The
marketing department pushed for their gimmick. Fred followed up by
saying he thought it was a mistake in marketing terms.
Hartmut wrote:
> My experience is that I rarely have to combat a strong
> cross wind. Runways are aligned with the prevailing wind
> directions and usually things work out just easy. I value
> the peace of mind of the two control airplane more than
> I would add rudder pedals for these rare occasions of
> cross wind landings.
Wow! Your years of flying in the U.S. seem to have been not,
primarily, in the American Midwest and Central States. We have lots
of airports with single runways and LOTS of days with strong winds
directly across those runways. Many runways are oriented N/S or E/W
because that’s the plot of land they could get (as the fields and
fence lines are primarily on the grid). The listed “most common” wind
is from the northwest at around 310˚ or so. We get lots of winds,
often strong, from all around the compass. Many’s the time I’ve gone
out and deliberately practiced in 20-30 mph direct crosswinds and I do
mean DIRECT. On quite a few cross country trips, I’ve found my fuel
stop or destination runway to be exactly crosswind. That’s life in
the center 2/3rds of the U.S.
Ed
