Newbie First Flight - Nexus Legato

Newbie First Flight - Nexus Legato

Post by Rick Fadde » Thu, 09 Apr 1998 04:00:00



Yesterday I flew an RC Helicopter for the first time.  After all
the wondering - I was fairly surprised.  The Heli felt like it was on
"autopilot" (almost).  It was a day when everything was finally ready -
all sorts of preparations, and then as I finally get the Heli on the
training gear - I'm at the site used by the locals, and Way too much
Wind!  It was a strong afternoon Bay Breeze, and I thought - "cancel" -
go home - because the wind was very strong.
     Well I just couldn't resist trying to get the Heli to roll around
on the Wiffle Balls, or otherwise show me what it wanted to do as power
was increased...  Surpisingly the Heli got "light" and then would lift a
few of the balls very easily - with the lifting coming far sooner than I
thought.  I had spent the time breaking in the 4 cycle engine on a
stand, with a prop, and I had been running the thing at 12,000 RPM -
putting out quite a noise...  Having gotten used to this sound level I
was just surprised to see the Heli lifting off while putting out a very
mellow, mild burble.  It was like you could hear the blade and
mechanical noise more than anything else.
     I carefully increased throttle - the heli remained arrow straight
and it easily lifted up and remained mostly in one spot.  I'd get some
slight drift, but it wasn't requiring any sort of rapid response from
me.  I was mostly aware of the high wind wanting to transition the Heli
into clear forward flight.  I think the Heli was mostly clear of its
downwash, due to the strong breeze, and at times it would just start
sliding forward - like on rails - like it wanted to just go fly!  I
stopped the forward motion, and I practiced hovering - very steady at
about three or four feet off the ground.  My plan was to keep the wiffle
balls just 6 inches or so off the ground, but in the wind the Heli had a
tendency to "balloon" up a few feet, then as I adjusted throttle down
(very slightly and smoothly) it would pop out of the balloon and sort of
drop.  I would catch the throttle a bit - a few times the Heli would use
the training gear like springy landing gear to absorb just a little bit
of "down" motion.  So... I did do some slight altitude "bouncing" - very
very mild though, and I figured that was aggravated by the strong wind
blowing the rotorwash downwind.
     The amazing thing was - within a minute or so I was hovering
motionless - like on rails - while at the same time my two boys happened
to be screaming wildly like maniacs while they "wresled" in our car,
next to me.  They picked the absolute worst time to misbehave, and they
were absolutely "off the scale" in the car next to me while I was
hovering.  If I was going to be distracted, that was the kind of
behavior that would do it.  I gently set the Helicopter down, then dealt
(also gently) with the boys.
     My biggest shock was this amazing hovering helicopter wasn't enough
of a sight to keep the two boy's interest...  Oh well...  but back to
the Helicopter...

     After 1/2 tank of gas (I had not filled the tank all the way - due
to my previous problems with the high tank location) - and seeing the
fuel down to less than 1/2 inch in the bottom - I called it a day,
packed up and brought the boys and Heli home.  Now its the next day, and
I'm getting ready for some more hovering practice.

     I guess the Legato 4 cycle with O.S. Max .52 is not the best for a
first Heli...  since as reported here - I had problems with the
Heli/Engine combination.  Here's what I did before my first flight:
First, I've been practicing on my Tru-Flight simulator...  then, after
building the Heli, I ran it first on a home-made test stand (the stand
holds the Heli landing skids).  On the test stand I found the engine
flooding unmercilessly.  Suggestions from this news group helped me
solve the problem.
     Most informative was running the new engine on a break-in bench
with a prop which allows RPM to match the reported top RPM in the Heli.
I got to learn the effects of Needle Valve setting with hands-on
adjustments while at full throttle.  I got to hear the engine actually
running rather sweetly after a carefully controlled bench break-in
effort.  Then I got to experience the effects of low-speed jet settings
with the engine fully broken-in, and with it sitting on the bench - with
my hand directly controlling the throttle.
     In my opinion, the low speed jet setting would have been very
difficult with the engine in the Helicopter.  As you can tell, I
adjusted the engine on the bench, then put it back in the helicopter,
and then I attempted to get the fuel tank height to match what I had
been running on the bench.  Based upon a News reply, I installed a
"Header Tank" at the ideal height with respect to Carburetor height.  I
also installed a fuel line clamp to help in case I had a repeat of my
previous problem: fuel dribbling from the carburetor and flooding the
engine prior to starting.
     Well my remaining question, I posted here and got no reply...  One
Legato flyer had relocated the fuel tank to solve the problem of high
fuel tank location with respect to carburetor location.  I never did get
the relocation details clarified...  something about building a new
landing gear from rectangular bar stock...
There was also the suggestion of using the Header Tank.  I tried to get
someone to confirm that a Header Tank can not solve the problem of a
main tank located too high...  It seems to me that the pressure is
simply conducted through the Header Tank...  I installed the Header Tank
anyway, and the results were described above.  Without adjusting the
needle jets I was able to hover with a seeming "effortless" sound from
the engine.
     One other thing I did which I think helped with my first flight...
I put quite a bit of effort into getting the ball links to fit exactly
as described in various expert books on Helicopter setup.  I bought a
Ball Link "adjusting" tool from Helicopter World, and I transformed the
Heli setup from rediculously stiff to an apparent "just right" setup.

     By the way, "Helicopter World" has received a bit of bashing here
lately - I'm guessing this is well deserved bashing - but in my case
having them as my "local" store has been wonderful.  They had every
single "gizmo" that I needed.  Believe it or not, the guys there also
gave me some great expert advice.

     As the experts have advised here in this newsgroup - the Heli
simulator is an incredible training aid.  With it you are prepared for
hovering practice with a real R/C Helicopter.  The only "hands-on" help
from an expert was the Heli test stand running - where someone who flies
looked at the blade tracking and declared the Heli as "right on."  He
said "put the Heli on the training gear next time, and fly it."

     OK, after breaking in the engine on a stand, and adding the Header
Tank, I did fly it.  I suppose the fun really begins now...  I can't
wait to get out and hover again.  This time with less wind I should
learn quite a bit!