Since I figured
out the Pico Stick, I've been searching for
a good aerobatic trainer -- something smallish (mostly for aesthetic
reasons -- I like small planes), medium speed (faster than the Pico
Stick or Tiger Moth and fast enough to do aerobatics, but not a pylon
racer), with full controls and predictable flying characteristics.
The Formosa might have worked, but in its
current state it's frightfully underpowered with the stock motor, and
really doesn't fly well enough that I want to invest in a bigger
motor. Besides, it's big and heavy. The Sporty
was cool looking, but it can only fly fast -- try to slow it down and
it tip-stalls and spins, too unpredictable for aerobatics.
On a tip from Perry at Aeromicro,
I took a chance on a Lil Hornet kit. (Actually, Perry recommended
a Crazy Max, but Dave had a bad experience with the Mini Blue Max
fuselage breaking -- other Crazy Max owners have had the same problem
with that silly triangular flexy foam Wattage fuselage -- though since
then we've found the perfect solution to the Max
fuselage problem. What Perry said was that he had one he'd
put some incredible number of flights on, and loved it.) It
claims to be a cross between big aerobatic planes, and small slow park
fliers. Sounds like just what I needed!
Opening the box was a disappointment.
I'm spoiled, I guess; I'm
used to ARF planes that are mostly assembled already (though they
always require more assembly than you expect, somehow). The Lil'
Hornet was a pile of wing skins (needing to be glued together -- the
Lil' Hornet's wings are skins around a balsa spar, so you get a very
thick symmetrical wing with most of the center being air), some balsa
pieces, a bag of motor parts, some photocopied instructions with no
illustrations, and the blueprints (in lieu of illustrated
instructions). Looking through the instructions, I was tempted to
take it back. But I didn't have any other likely aerobat in the
pipeline, and I'm tired of just the slow-fliers, so I dived in.
I could see right off that I'd need to make changes. The fuselage
is a stick of ... balsa! Everyone says that breaks right away,
and you have to reinforce it ... no surprise! Instead, I bought a
stick of hardwood the same size.
The motor is a "Johnson motor" which everyone says is (a) underpowered
and (b) amazingly short-lived. I was going to try it anyway,
until I saw the instructions and discovered that you have to basically
build your own gearbox by soldering and glueing a bunch of metal and
wood rods and tubes. Sheesh, that's too much work for a motor that
everybody says I'm going to replace right away anyway. So I
decided on a GWS 350C (that's what Perry said he used until he upgraded
to a brushless), one advantage being that we had several of them
sitting around from other airplane projects, so it was no risk to try
Perry said the rudder was way too small and I should make a bigger
one. I actually did cut a bigger rudder, but then at the last
minute I didn't use it: Perry flies 3-D and I don't, and I had too much
tail weight as it is (due to the hardwood spar) so I decided to try the
original, and switch later.
Finally, Perry said to reinforce the wings with tape -- the plane is
fragile without that. Fragile is not a good thing for me, so I
took that as gospel. Besides, the center wing spar looks fairly
feeble (the plastic center section is really what holds the wings
together) so I wanted to help that a bit.
The building actually went pretty smoothly, despite my initial
dismay. It took about three evenings. Setting up the jig
for assembling the wing skins was tricky, but everything glued together
fairly well (the tape didn't stick -- very little sticks to this foam
-- but that didn't seem to matter). I'm a bit dubious about
EZ-Hinges on the outside of balsa -- it was tricky to get those to
stick, and I had CA on my fingers for days afterward (I didn't have any
CA debonder; now I do). Besides, they're ugly. But once I
finally got them to stick, they seem to work fine.
instructions seem to assume you're going to set it up with no
rudder, even though it's billed as a fully aerobatic plane. The
servos are all crowded together and it's not at all obvious where the
rudder pushrod should go so its servo wheel doesn't collide with the
one from the elevator, nor where to put the guide for elevator and
rudder. I winged it, building a sort of fin that sticks up from
the fuse halfway between the wing and tail.
I used wood glue for building the wings, because I didn't have
Elmers. I used CA glue almost exclusively for everything else
(foam-safe CA for anything near the wings). It isn't as strong as
epoxy or wood glue, and that turned out to be a good idea (see below,
I wasn't going to use their weird "glue together the two halves"
wheels, but I glued the halves together just to see what they were like
-- and suddenly I liked them, and kept them.
The engine had to wait until last, because I had no idea where it
have to sit on the stick (which I left quite long in front) in order
for the balance to work out right. Ironically, it ended up right
at the end of the stick I had left, a couple of inches forward of where
the original design put it -- good thing I didn't leave the stick any
shorter! Then I had to shave down the top and bottom of the
stick, and add some balsa on either side, to get the square profile
needed to stick into a GWS 350 engine mount. The motor looks
kinda strange sticking way out there ... oh, well!
I used Zagi tape to reinforce the wings -- it's thin and light, and
comes in nice decorative colors. Dave said to spray Super-77 on
them first, since tape didn't stick well. I tried that on a scrap
piece first. Good thing! It melted the foam, then stuck
well to the stuff under what melted. I elected to just use the
tape alone and hope it stuck well enough.
It came in at 9.5oz without battery, just under 11 oz with a 1300mAh
Li-po; quite a bit more than
I'd hoped. Probably all that tape, not to mention the hardwood
stick. But it's still a lot lighter than the Formosa, with the
Flying and Aerobatics
was pretty windy at Baylands for the test
flight. Oh, wait,
it's always windy. Never mind.
The way-too-brief instructions didn't say anything about recommended
control throws, so I just guessed.
I gave it about 2/3 throttle, figuring that it should be way
overpowered, pointed it into the wind and tossed. (Baylands has
tall grass, so rolling takeoffs are difficult.) The plane just
floated off, kinda like tossing a Zagi-type wings, leaving me plenty of
time to get to the controls.
The Lil' Hornet flew wonderfully! It flies slowly due to that
thick wing, even with the big engine; but it doesn't have the
susceptibility to gusts that the super-lightweight slow fliers like the
Pico Stick have, and that engine gives it reasonable wind penetration
(though later in the afternoon when the wind picked up, I had trouble
I had what I thought might be too much aileron throw with those great
big ailerons, but the roll rate was actually quite slow. I had no
trouble making as sharp a turn as I wanted, but it doesn't have that
instant-roll that the Sporty had. That made me nervous about
trying an axial roll, but it turned out the symmetrical wing makes it
easy to feed in a little down-elevator in the middle of the roll to
stay on axis. (I still don't get it right most of the time, but
I'll learn.) I bet it'll do lovely inverted flight, once I work
up the nerve. Loops are easy -- none of the going-off-center that
I saw in the Sporty or the Tiger Moth -- as are Immelmans and
split-esses. It spins and snaps very gently, needing some effort
to stall that big thick wing (moving the CG aft may change that).
Cut the engine, and the plane floats slowly back to earth, with plenty
of control. It does become more susceptible to wind gusts when
flying slowly, but otherwise it glides just fine.
Unfortunately, on the third day out while I was enjoying the Hornet's
aerobatic capabilities, it was t-boned by a high-speed ducted fan
fighter. :-( It was a spectacular crash, if you weren't one of
the two pilots involved, with both planes exploding in midair and
pieces flying everywhere. But Lil' Hornet II is flying now, and
it flies just as well as the first one.
Lil' Hornet II has crashed once too, mildly. The engine gearbox
broke, the tail came off (intact, horizontal+vertical stabs came
cleanly off the main spar) and a piece of aileron broke off.
Repairs were easy (except for nobody having replacement gearboxes,
apparently GWS is backordered). I highly recommend using only CA
to glue the tail to the main spar, so the joint is a little weak and
will separate cleanly.
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