The whole incident, from start to finish consumed about 3500 - 4000 feet
of
the 6000 foot runway. She was off the ground before the 2000 foot
marker.
And today was not a standard day -- DA this afternoon was about 8300
feet.
So yeah -- plenty of get up & go.
Agree on the slower warm-ups vs blasting down the runway at full
power...
Live & learn I suppose...
Mark
Mark,
You might not need to make any more high speed taxi tests, but a good
suggestion was made by a friend of mine. Run it without the wings on
until
you're ready to fly. You can go as fast as you want without unexpected
aviation.
Bill jEPSON
On a canard airplane, if you take the wings off, be
_sure_ to take the
canard off too. If not and you accelerate to near rotation speed, the
aircraft will likely flip over uncontrollably due the center of lift
being so far forward.. An early Varieze or Long EZ was significantly
damaged because of this.
Regards,
Matt-
Matt, et al,
Other than to test the engine, what is the purpose of the high speed taxis
sans wings? Do you have any concern about torque roll on the ground? You
should be able to get a good idea of tracking with slow taxi tests. Your
brakes will not be as effective at the weight which will be much liter
since
there will not be much weight on the wheels (skidding).
If your plane is ready to fly, do graduated speed runs aiming for a
particular target airspeed, chopping the throttle and bringing the stick
back. 5
mph (K) increments would be good. At a given point, the nose will raise
off
of the ground and allow you to gently put it back. (don't yank the stick
back, but give it just a little tug.) Because the thrust is now 0, the
nose
should settle back.
However, be prepared to fly the aircraft in case of a malfunction.
This will give you some numbers as well as confidence handling the
aircraft
at takeoff speeds.
If you use too much of the runway in this exercise, your runway is too
short.
Rich
I'm not a fan of high speed taxi without the complete control system
installed and functioning. I think it's generally a dumb idea.. I
was just making a comment about one of the (possibly not so obvious)
hazards of doing so..
I think ground running is a tough question.. You'd like to run the
engine enough to gain confidence that it will function well, but you
end up exploring areas of operation which are often irrelevant to how
an airplane will be used - high power with zero airspeed isn't
required of a normal airplane. On a reciprocating engine you may
cause a condition which makes it difficult to properly seat the rings
on the freshly honed bore. I don't know if that concern exists with a
rotary - do the apex and side seals "seat?"
Rather than extensive ground runs, I'd prefer that new engine installs
be tested at an airport where landing after an engine failure or burp
or hiccup is basically expected, and where damage because of such an
event is unlikely.. A big airport with runways crossed in a triangle
would be ideal.. Expecting a failure and being surprised by continued
operation will help you be in the right mental state for dealing with
whatever happens.
Rich, your suggestion for how to sneak up on a first flight seems like
a good one. It's essentially what Rutan suggests, and is the method I
used for checking myself out in my Varieze. Gaining recent experience
in the same type of airframe prior to first flight with a new engine
setup should be just about mandatory in my opinion. Or at least
recent experience in airframes of several different types will be
good. Go get some glider, some tailwheel, some retract, some Cessna,
and some RV time. Spend some time transitioning back and forth
between slow flight and cruise flight, both turning and level. If you
get glider time, practice rope-break exercises, and in a powered
airplane, practice engine failures. It will sharpen your flying
fundamentals and get you used to dealing with the variety of control
feel and responses you can encounter. It will make it less likely
that you will suffer PIO or porpoising.. Make sure the new airplane
has zero control slop and friction in the elevator (for the same
reason).
Regards,
Matt-
If one has great concern about handling the aircraft they just built on
initial flight testing, perhaps they should consider getting someone else,
who is very experienced, to perform these preliminary flights. Or, at
least, get experience in a similar plane so that you don't end up testing
your flying skills at the same time you're testing your aircraft!
Georg Lasik
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