My Stik 30
has been a simple model from its inception.
The model flew well but had some teething pains. Over the years since I've built the
model I've made various tweaks and modifications to it.
A lot of its history is detailed in the My Stik 30 article but the
article tends
to ramble and the chronology is hard to follow so I'll recap here as briefly as
possible.
The model was originally designed to fly using my OS Wankel 30 Rotary
glow engine. I
thought a small Stik model would be a good showcase for the
engine. I
made provisions to use other engines hoping that the Wankel would be a good,
reliable engine and the only engine the model would ever need.
Unfortunately, the Wankel used so much fuel that I installed a Webra Speed
.32 almost immediately. I could never get the Webra to run properly. The idle was simply too
rich — even when the idle needle was turned all
the way in. I could have been using the wrong fuel or who knows what.
A
week to the day after the plane was completed I was shooting touch-and-goes and rolled a wing tip into the
ground at high speed. The plane cart-wheeled across the
field. The fuselage was destroyed but the wing survived with very
minor damage.
When I built the new fuselage I didn't care for my engine choices: an
old, worn OS .28, several worn .40 size engines and a brand new OS .46 FX
which was what I chose. Any good .19 - .30 engine would be plenty of
power for the model.
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The model when it was first completed had an O.S. Wankel
Engine. |
After the fuselage was destroyed a new one was built and
an O.S. .46 FX engine was installed. Way too heavy! |
The .46 was way more
power than the model needed but the structure handled it just fine.
The downside was that I added about 6-8 ounces of lead to the tail to
balance the model. That kind of weight at the extreme ends of a model
aircraft creates very bad inertia.
The overall weight gain was fairly significant and other than screaming straight
up at an ungodly rate of climb, the model wasn't much fun to fly once I got
over the screaming straight up part.
I
put the wankel back on, chiseled out a bunch of lead, replaced some servos
with lighter ones and in general lowered the weight by a lot. The
model was flying very nicely again.
And that's the state the model was in when I began this rebuild.
The only really serious design flaw is that the model can't balance
properly with a .30 class engine due to the long nose. When I took the .46 off the
model and chiseled out the lead I also built a
plywood hatch in the aft fuselage to
mount the onboard battery. But then I was back to weight in the tail
again and the battery was much larger than necessary to achieve balance.
So my primary goal is to correct the moments (shorten the nose) which will also reduce the
overall weight. If successful the model will fly much better than it
does now.
What actually motivated me to do this rebuild was that the model was
getting really ugly in ways I really don't like.
Uglinesses
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The Wankel spews out more exhaust gunk than any
engine I've owned. The aft battery hatch was always covered with
fuel exhaust inside and out.
-
While I liked the fin/rudder shape on the
original fuselage, I (out of laziness) cut an ugly round one for the fuselage built after the
crack up. I used
Robart 1/2 hinge points for both
the elevator and rudder. These
hinges were too small and frail for a model of this type
and for the kind of abuse I subject it to. A few of the
hinges broke so I replaced all the hinges with flat hinges. That left more
ugliness in the tail where the original hinges were.
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I used
Oracover on the elevator and stabilizer and it liked to
turn into a balloon in the hot Florida sun. It didn't matter how
many times I ironed it down or what temperature, it just wouldn't stay
adhered to the wood. It was ugly and I hated it.
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One day my shop
foreman chased a bird through the house which landed on a shelf
and knocked a bunch of stuff down on the fuselage below. This left a
lot of ugly gouges in the upper decking that couldn't be repaired nicely with the natural
finish. I filled the gouges with
balsa
wood dough and
then sanded and fuel-proofed using more
epoxy.
I would also like to update the wing — particularly the color scheme but
it may be a while before that happens. First, I want to make sure the
primary modifications will make the plane better without giving myself
unnecessary work to do. Second, if the plane does fly as well as I
think it's going to I'll want to fly it for a while before I ground it for
as long as it will take to modify the wing.
I don't plan to rebuild the wing as I did with the fuselage because it
has nothing wrong with it. What I will probably do is add wing tips
and scallop the ailerons. I'm mulling over various finishes and color
schemes trying to decide what will look good with the rebuilt fuselage and
tail.
Getting started
This series of articles will proceed more or less with each portion of the
model that was rebuilt from the beginning through completion of that
particular portion.
The model was straight as built. I didn't want to do anything that might make
it crooked. I took a methodical approach to removing parts and
replacing them rather than removing everything at once. For example,
all the decks on the model were replaced. But I removed only one deck
at a time and built the new deck before removing and replacing the next
deck.
Before doing anything else I removed all the equipment from the model, cut
off the tail and sanded the fiberglass finish from the fuselage sides back
down to bare wood using 60 grit sandpaper.
In this series
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