Big fast planes
are okay, but I prefer small, slow, quiet
planes. Planes that can fly anywhere, and don't require
travelling to a big field. After all, that's why I quit flying
alcohol fuel planes and got into electric this time around.
I have a couple of small-field planes -- the Edge
and the Triangle -- but they're both quite
fragile, and difficult to transport since neither one
disassembles. I wanted something I could toss into the car (or a
suitcase) and take with me without having to worry about it.
I had been eyeing the Mini
IFO for quite a while. IFO stands for Indoor Flying Object,
but you can't take the word "indoor" too seriously in this hobby; lots
of things say "indoor" and what they really mean is "indoor, if you're
allowed to fly in the Moffet Blimp Hangar."
Lots of people around here have Mini IFOs, and carry them around when
they go flying. Nobody ever flies them. The couple
of people I've asked say they like it, but also say that it flies fast,
that the Lazy
Moth is much slower and more appropriate for indoor and small space
flying. The Lazy Moth also intrigues me (I've seen them fly a
number of times, and they're very cool), but it's a lot bigger, and
being a rudder plane with no ailerons, it's not very aerobatic, while
the Mini IFO claims to be.
So I finally broke down and bought one.
The Mini IFO is a bit tricky to build, but doesn't take very
long. The box said "build in an evening", Perry at Aeromicro
predicted two, and Perry was right (as usual). Construction
involves holding carbon fiber rods together while wrapping kevlar
thread around them, then soaking the thread with CA glue and spraying
with accelerator. This works well and is fairly easy, except for
the handful of steps where you have to hold tension on the carbon fiber
rod somehow with one hand while doing all of the above with the other
hand. For those steps, it usually took me three or four tries
before I got all the thread wrapped enough to soak 'n' spray without
releasing my one-handed tension on the assembly too early.
I was disappointed that the photo on the kit shows a contrasting tail
color, but doesn't actually provide more than one color of ripstop
nylon covering. If you've ever tried to fly a plane that's all
one color, you probably know that it's very difficult to keep track of
which direction it's going. In fact, I crashed the Mini-IFO the
first couple of times I flew it because it went inverted and I didn't
know it and couldn't tell from looking. I ended up using yellow
Zagi tape as a temporary measure, because I couldn't find any ripstop
nylon at the local fabric
Micro carries it (from the same
company that makes the IFOs), but $10 for enough to cover a
whole IFO when all I need is 6" square for the tail?
The battery holder and servo mount designs are just plain
inadequate. I can't believe that the builder actually flies this
way (maybe he never, ever, has a hard landing). I lost the
battery on the first flight, the servos on
the second, the fixed battery on the third, and finally ended up
completely redesigning both systems by making sandwiches of three
layers of (non balsa) wood with a slot for the fuselage rod to pass
through. That's held up for several flights so far; maybe it'll
keep holding. The IFOs are billed as being fairly rugged (the
larger T-IFO trumpets "Learn to fly by flying, not repairing!") and
they may be, but not with the equipment mounts built as designed.
(See below, Reconstruction,
for some other tips I learned later.)
The instructions for making the one wheel say to rough up the wire with
sandpaper before thread-wrapping and CAing it to the long carbon
rod. I skipped that part, which was a big mistake. I ended
up with a wheel that could freely rotate -- the glue didn't hold it --
so it was useless for rolling. Don't skip this part. (But
consider leaving the gear off entirely: see below.)
Aside from that, the instructions were pretty good and it wasn't nearly
as hard to build as I first feared when taking it out of the box.
I powered it with a GWS IPS-A motor (the gearbox gets glued in as part
of the build, so changing it isn't a casual thing) and I've used either
a 9x7 or 10x47 prop. The 10x47 gives it a bit more thrust at low
speeds, which is good, but it also has more torque effect, which makes
it a little harder to catch.
I couldn't wait. I have no patience, and besides, time was short
as I was leaving on a trip in a few days. So my Mini IFO had its
maiden flight on my street corner, at night under the
streetlights. I know that's stupid with a new plane, but hey,
flying in small spaces was why I bought this beast, no?
set it down on the street, pointed into the wind, gave it a tentative
bit of throttle ... and it launched promptly into the air. It's
quite impressive how little throttle this kite needs to take off --
less than any of my other IPS planes, even though it's not all that
much lighter and it just has a flat wing with no airfoil.
Unfortunately, something confusing happened that I couldn't quite see,
and it ended up bonked on its nose in the middle of the street.
"That was pretty gutsy, trying it inverted like that right away," said
husband from across the street. "Uh, inverted?", said I. I
had no idea I'd been flying around inverted prior to augering in.
Turns out the IFO flies great inverted, and in fact loves to flip
inverted at the slightest provocation, and if you don't have a
contrasting colored tail, it's very difficult to tell. (This
wasn't just a night/streetlight issue; the same thing happened again
the next day, flying at a park on a sunny day.)
Once I got past flipping inverted, I experienced another weirdness: I'd
fly around for a while just fine, then go into a shallow dive (perhaps
preparing for a loop) and the IFO would just nose down, refuse to come
out of the dive, and crash. This happened twice. My theory is
that my control wires were too small. I didn't use the pull/pull
system recommended in the plans (though in retrospect, I probably
should have), but rather a normal system of control
wires from the servos to the underside of the elevons. This
can work, but use thick, beefy wire: it has a long way to travel and no
support along the way. Once I switched to thicker wires, this
problem went away, and the IFO started flying much better.
And it does fly! I don't know why everyone says it's too fast; it's
probably the slowest flier I have. It can fly nicely at 1/4 thottle of
IPS, and can hover or land gently straight down in only a slight
breeze. As mentioned previously, it flies great inverted; it
loops and rolls okay, but it needs an amazing amount of elevon throw
(even more than the recommended 2") and I'm having trouble getting that
much even using micro control horns and my longest GWS servo arms, and
overcranking the servos at the transmitter. With a little over 2"
throw (that's each direction, believe it or not) it does quite
competent if not spectacular loops, both inside and outside, and
slowish rolls (not the 2-per-second mentioned on the box).
The battery and servo mount frailty were discussed before, under Building.
Otherwise, it might actually be reasonably rugged ... time will
tell. I like the way the front carbon rod protects the motor at
least to some extent; you can still bend or break props, but any
serious motor damage is unlikely.
The pivot for the landing gear (a fairly cute and ingenious setup,
incidentally) also seems to be working loose; I needed to brace it with
an extra kevlar line running from the top of the
stick running backward (because it can't run from underneath forward --
the motor is in the way).
Mini IFO Version 2
I finally saw someone else with a Mini IFO, at a local indoor flying
group. Lots of people here own them -- I see them on tables, or
people carrying the boxed kits, all the time. But you hardly ever
see anyone fly one, which is one reason I hesitated so long before
This fellow obviously knew what he was doing, accomplishing aerobatics
in the tiny half-gym where I was wobbling around trying not to hit the
wall, so I took a close look
at his plane, and learned something interesting: he had built it upside
down. All the gear was on the same side as the tail. Also,
his IFO didn't have the landing gear.
The more I thought about it, the more sense it made. If the
battery and servos aren't hanging down, then they're less likely to rip
off in a hard landing. The wheel never worked well for me anyway,
because it wouldn't stay pointed straight (perhaps my fault for not
sandpapering the wire first), and it adds weight. So I rebuilt my
IFO: I removed the landing gear, removed the tail attachments, then
re-glued the tail attachments at angles which would work for the tail
on the other side. (I used CA debonder, wire cutters, and an
x-acto knife to remove the existing pieces.) I also moved the
tail forward slightly, since my IFO tends to be fairly tail heavy, and
for the vertical piece I used a much longer piece of carbon fiber rod,
compared with the short plastic rod the original design used, to keep
the tail in place better -- it's rather floppy as originally designed.
I'm quite happy with the result. It flies much better with the
de-flopped tail (which still flops, but far less than it used to) -- I
definitely recommend using a longer vertical tail support than the
design calls for. The
electronics are better protected on the top side and less likely to
detach on landing, and the lighter weight (about 4.6 oz including a
500mAh 2-cell lipo battery) means it can fly
even more slowly than before (good for indoor and small-field
Rolls are much more controllable (I'm sure that's the improved
tail) and it's fun to practice flying between trees in parks. I
only hit the trees now and then. Of course, landings are an issue
now, since it now has no
protection from scraping the ground; but the wheel didn't protect it
much, and it's pretty rugged anyway. And now that it flies so
slowly and controllably, it's surprisingly easy to catch: even a klutz
like myself can catch it most of the time.
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