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by Glen Peden
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by Glen Peden
Introduction:
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When LA Heli showed photos of their new auto-gyro park flier named the RotorShape, I had to have one. What a fun toy to bring out at fun fly's, I figured. I saw a video of it flying and it looked like it might be like flying a 3 channel high--wing aircraft. I wrote this review before the successful flights happened and wrote about my misadventures while I progressed towards success. At this time I've decided to leave them in the review, hopefully to inform or entertain. The kit for this review was provided by Glen's Little Heli Shop (me). Hey, it's better than wondering how some other guy is doing with the kit and letting him have all the fun:) |
photo by Martin Hunter |
Photos: Please click on the photos to see a higher-res
enlargement
Kit Specs (actual/used):
Rotor Span: 680 mm Length: 540 mm RTF weight: 300 - 400 g (350
g) Motor: MPJ AC22/7 -60D Battery: LiPO 3S 1000-1500,
must weigh around 130 g (Etec 1700 ) Rotor blades: LAHeli
wooden Servos: two HS-55 (a
must) Controls: aileron and elevator
(cyclic), configured as elevon in the transmitter,
throtle Speed control: TMM easy 12 (used
for review), CC-Phoenix 10, Jeti 8, etc. Prop: APC 7 x 4 Slow
Flyer
Rotorshape Kit Requirements:
The Rotorshape will fly with basic
airplane controls in a DELTA WING configuration. Two servos
are required. Apparently the balance of this model is very
important, as specific weights and locations of equipment is
shown on the plans. I went along with Icare's
recommendations for motor, an MP Jet 22/7-60D outrunner and
an APC 7 x 4 prop. A TMM Easy12 ESC and a Berg Microstamp 4L
receiver were used in the finished model, although a CC10
ESC was installed during construction. I purchased a prop
collet to fit the shaft of the motor, but then discovered
that one was included in the kit! GWS HS-55 servos are
recommended and one needs to be careful when substituting
for these because there's a molded plastic frame piece that
supports each servo on the ends of two plastic posts. Exact
mounting hole spacing and a maximum servo length are
required. The plans also specify a 130 gram 11.1 volt
battery.
Rotorshape Kit Contents:
There is a lot to this kit, more than I
expected, with lots of tiny nuts and bolts and pieces. The
body consists of fiberglass sheet plates joined to a molded
plastic firewall and a molded plastic rear piece which
serves to join the tail boom, rotor mast and body as well as
having the previously described servo mounts - all in one
molded piece. The boom and mast are carbon tube. The blades
are made from dense balsa with a hardwood leading edge (I
think), shaped and drilled for the mounts, ready for sanding
and covering. The tail feathers are depron pieces cut to
shape, with a hardwood leading edge to be glued to the
horizontal stab. Pre-formed landing gear legs and very light
wheels are supplied. One thing that is lacking is a detailed
set of instructions - six steps / eight sentences for
assembly and roughly the same for each of setup and flight.
Adequate drawings are supplied though, and after handling
all the pieces for a few minutes, confidence was
high. On the left is shown the rotor head components at the top
of the photo and the molded pastic pieces in the lower half
of the photo. On the lbottom eft is shown the tail pieces.
Rotorshape Body Assembly:
The first assembly I examined was the fit
of the fiberglas (G-10) body pieces. There's a series of
slots in the vertical sides into which nubs on the
horizontal "floor" are supposed to fit. The nubs are too big
and at first glance one might think that a lot of work will
be required to fit these pieces together. A technique was
quickly found where an Xacto blade was inserted towards the
rounded ends of the slots. A couple of side-to-side scrapes
of the blade to square off the rounded ends of the little
slots was all that was needed. The inside faces of the two plastic
firewall halves were given a quick swipe with a sanding
block to take down any high spots. The nuts that are
captured inside the two halves were given a drop of CA to
hopefully pin them from breaking loose inside their hex
shaped pockets. The landing gear was placed in the channels
inside the firewall halves and the assembly held in perfect
alignment with pinched fingers. The edges of the pieces were
pulled away a bit as CA was wicked in, one section at a
time. I figured that the best way to get the
frame straight was to assemble all the pieces and wick in CA
in several sections, while holding things tight. As the
frame was assembled, all joints were inspected for a tight
fit. Accelerator was applied in some areas as the CA flowed
into the joints. Those darn slots were a conduit for CA into
my fingers and much of my fingertip skin had to be scraped
off the frame sides later. The molded plastic piece at the
rear of the frame is the component around which everything
else is assembled. At this time the carbon tubes for the
mast and tail boom were trial fit. The plastic rear bulkhead
which pins it all together seemed very flimsy and I wondered
how there'd be any rigidity of the mast. Of course once the
carbon boom and mast were CA'd into place, it was very
rigid. Also the servos themselves serve as structural
members. The assembled structure seems quite strong and I
hope that it is very resilient because I thought that the
days of having to debond CA joints were gone as long as the
Piccolo and Hornet heli's remains stay stashed in a
box:)
Rotorshape Rotor Head:
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The rotor head looked like a neat puzzle to solve as I stared at the exploded view. The plastic and fiberglas sheet parts that make up the blade attachment area can be assembled separately from the lower mechanical part of the head. Note that the fiber sheet with the smaller center hole (and a V etched in it) goes on top. The clear plastic piece is sandwiched between the two fiber sheets. I started by inserting the 4 longer screws in the center - the ones that eventually go in the hub. Then the 3 shorter screws and nuts were inserted and tightened. The two bearings were inserted into the hub and the smaller one needed some persuasion with a socket driver that fit nicely on the outer race. |
Assembly is begun |
The head assembly is shown in the photos with elevator and aileron input. The yoke (piece in which the head pivots) seemed somewhat malformed in that the side plates slanted inward. The fit of the inner plastic piece seemed a little tight, so it's sides were filed down a bit to make the fit not so tight. Once the grub screws (with plain shoulders) were inserted and tightened up, the sides bent out a bit from the tension. The alu rotor hub was removed from the demonstration mockup and assembled to the plastic & fiber pieces in the upper head assembly. The carbon control arm was centered in the aluminum post and secured with a couple of drops of CA. |
Elevator cyclic movement |
 Basic layout of the head assembly. The clear plastic is a single flexible piece that allows the blades to flap and is their only attachment to the head. |
Aileron cyclic movement. |
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The assembled head is shown on the right. The black plastic pieces clamp on either side of the clear plastic piece and because they butt close to the inner structure, limit how much flapping can occur. |
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Rotorshape Equipment installation:
Motor installation The MP Jet AC 22/7-60D out-runner motor
has a 3-hole, 120 degree motor mount, so two holes were
marked ad drilled to suit the 2 hole, 180 degree mounting
that the firewall provides. I decided not to put the
receiver right behind the battery as suggested in the
manual. Instead, the tiny Berg 4 "Stamp" receiver was
attached to the inside wall of the body, below the battery
platform. The speed control was positioned just behind the
firewall, hanging by its wires. Electronic gear stashed here Perhaps I'll shorten them later, but the
HS-55's long leads were bundled up and ty-rap'd to the boom,
under the battery platform. The "stock" HS-55's mounted
nicely on the posts provided for them, except the leads were
bent and pinched tightly against those posts. So, a bit of
the post was whittled away to relieve the pressure on the
wires Making up the long push-rods for the
mechanics was fairly painless. The longer servo arms had
been used, the radio already setup for the Delta
configuration, and the arms made to be level at neutral
stick. The ball links were fitted to the balls on the end of
the control arm. They were quite tight, so a good set of
needle-nose pliers was used to squeeze the links in a couple
of places (while still installed on the ball, of course) to
loosen them up. A 1 mm bit in a pin-vise was used to open up
the servo arm holes to the correct size for the pins used
with the servo arm forks and the servo arm forks were
fitted. The photo on the box clearly showed the middle hole
of the servo arm being used on the model, so I started with
that. In fact I lopped off the end of the servo arm because
I'd found that it hit the frame side. Testing showed that
the shortened arm just cleared the side. The plan was to
install the carbon push-rods loose in the links and get the
head tilted to the prescribed 6 degree rearward tilt and
freeze the pushrods in the links with CA when the proper
length was determined. I dug out a Hobbico "Builder's
Protractor", which I'd bought years ago and never really
used. This was perfect for setting up the mechanics! The
correct angle was set on the protractor and then it was
"read" by lining up one rule parallel to the edge of the
main shaft and the other one used to set the angle on the
control arm (part #G0302) while keeping the left/right tilt
at neutral . However you do it, the head must have a 6
degree rearward tilt at neutral stick. After this was
achieved, I checked the throw on the mechanics and found
that there was a fore-aft tilt of +/- 9 degrees and if I
understood the instructions correctly, +/- 8 degrees was
required. Good enough! It can always be reduced a bit with
the radio. The supplied motor collet did not fit the shaft
of the motor I purchased, so it's just as well that I
purchased one at the hobby shop and the APC 7 x 4 prop was
installed. The very light wheels supplied with the kit were
easily installed with the metal keepers. one of these
keepers flew off in a crash, so I recommend installing a
piece of heatshrink and CA to keep the keepers:) Setup with protractor
Rotorshape Tail Assembly:
The tail fin construction was started by
gluing the wooden leading edge to the horizontal fin. Waxed
paper was laid down to protect the table. A bead of
foam-safe CA was run along the wooden leading edge and the
two parts pressed together while laying flat on the bench. I
ended up using my long sanding block to press against the
flexible wood while the glue set. The wood was a tad thicker
than the foam, so the high side was carefully sanded flush
with the foam surface. I meant to round off the leading edge
but forgot. An angle of 145 degrees (i.e. 35 degrees off
horizontal) was specified for the tips of the horizontal
stab, so a 35 degree wedge shaped template was cut from
heavy cardboard. These tips were held at the proper angle at
the edge of the workbench by these templates so the foam
could be sanded at the correct angle for joining to the
stab. Template for shaping and gluing Finished tail assembly Then the templates were used to determine
the proper angle as foam-safe CA was used to glue the tips
to the horizontal stab, which was laid flat on a piece of
wax paper. I confess that my second favorite CA accelerator
(saliva) was used to help set the joint. The vertical fin
was glued in place using a small plastic square as a guide.
The plastic mounting clips were glued in place easily, but
their fit on the tail boom was rather loose. Rather than gob
on a bunch of black CA and be stuck trying to hold the
assembly in perfect alignment while the glue dried, I
decided to wrap the boom with clear plastic tape in a spiral
to help fill out the gap. Also, I figured that this might
make disassembly in the event of a crash a little easier.
This made aligning the stab a very relaxing task because it
stayed put while the positioning was tweaked.
Rotorshape Rotor Blades:
The manual suggests using lacquer, thin
adhesive tape, or heat shrink as finishing means. I was
thinking about using packing tape or Monokote trim, but was
advised on RC Groups to try lacquer first, followed by the
Monokote trim. The harder wood in the leading edge of the
blades was rounded and the whole blades' surface smoothed
with some fine sandpaper on a long block of wood. Some
attention was paid to the weight of the blades as I sanded,
trying to make up for the fact that I'd lost track of how
much I'd already done on which blade, hehe. A few light
coats of lacquer followed up with sanding were done to
smooth and fill the blades' surface. After seeing the
imperfections showing after the covering was applied, I wish
I'd done more to make it smooth, but it seemed OK. I decided
to make each blade a different colour to give the auto-gyro
a more "festive" appearance:) The trim tape was applied in
one piece, with the overlap just under the trailing
edge. A piece of trim about 2-1/2 times the
width of the blade was cut and slightly over half of the
backing removed by sliding a pair of small scissors between
the covering and backing as the backing was cut. This was
done to help prevent the material from curling back and
sticking on itself. The trailing edge was positioned a
quarter inch from the edge as the top of the blade was laid
down on the exposed sticky part. It the tape was kept pretty
flat, the material went on pretty smoothly as the blade was
rocked along it's curved airfoil. If all looked well, the
quarter inch overlap was wrapped around the trailing edge
and pressed flat. Then the material was started around the
leading edge and the rest of the backing removed.
Once the bottom of the blade was covered,
the excess was trimmed off with a sharp Xacto knife. the
ends were finished by making slices here and there to allow
for fitting around the edges. A bit of CA was applied to
these ends to help seal the tape in place. The plastic grip
pieces were installed and the knife used to scribe around
them so that the material underneath could be removed for
gluing direct to the wood. The blades were balanced using a
K&S blade balancer and the following method. The
heaviest blade (balance-wise) was found and then the other
two blades were weighed to match it by applying strips of
the same colour trim tape towards the tip.
A peek at the rotor head and shear pins:
Wooden shear pin is revealed The photo on the left shows how the
Rotorshape's shear pins work. The yellow blade's shear pin
has been installed with the blade pivoted off it's position.
This shows how the scissoring action occurs. The black
circles visible and also hidden under the head of the
blades' bolts are the parts of the blade's grip mount that
poke through from below. They are seen as the pieces
sandwiched closest to the blade surface in the photo on the
right. They are shown in the bottom of this
photo in the kit contents section
and they serve the important function of setting the fixed
negative pitch in the blades. Underside of rotor head
C/G balancing of the Rotorshape, an important issue:
Teetering on the steel rule The prescribed distance back from the
front for the balance point was marked on the body sides.
Since it was quite hard to balance in that location, I cut a
couple of small notches in those locations to balance on the
edge of a steel rule without slipping. A WAY bigger battery
than necessary is used for ballast, and an Etec 1700 HP was
my choice. While I thought I had it close, the balance
wasn't quite forward enough as evidenced by the first
flights. After the second flight I found an more accurate
way to balance. A steel rule was held level in a vise and
the model placed on that. A bubble level was placed against
the boom to determine precisely when it was level. Weight
was added to the nose until the teetering balance was found:
when the boom was level and the slightest movement in either
direction causes the model to keep moving away from level.
Approximately 3/8 oz. of weight was added to the firewall to
make it balance. The photo on the right shows the
sticky-backed weights ty-rapped as for security.
First Flights of the Rotorshape:
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Flight #1 Like they say, take the photo before you maiden it! It was cold, with (ironically) very little winds at first. Proper technique involves spinning up the blades by hand and getting the wind to sustain rotor movement by angling the model back a bit. At first it just wasn't working well at all and I discovered that the rotor head had gotten very tight, due to temperature differential I guess. After fixing that, I was able to get the little wind there was to sustain some rpm and then my foolish self decided that this was probably enough and I gave it a run and a heave. There was a slow roll to 90 degrees right just before it hit. The prop was sheared off and one rotor blade was removed from the head because the inner flexible plate that allows movement/dampening broke. This part costs only $2.00 fortunately. Just as I was picking up the wreck, the winds came up very nicely, Thank you. So the moral of the story is to pull out the auto-gyro for the first flights only when it is windy. |
 All it took to recover from the first flight attempt/crash was that 2 dollar part and and re-doing some CA joints that popped, so I'm definitely impressed. That part, the inner flexible core of the rotor head, probably snapped because I'm using round toothpicks (perfect fit, hehe) for the shear pins instead of so-called "balsa slivers" that were suggested by LAHeli, but missing from early kits. |
Flight #2 For the second flight there as nice
winds, but they were a little gusty. I got the blades
revving up very nicely and tossed it into the wind. It
zoomed up and peeled off downwind. Hey, the silly thing was
flying! It took a few seconds to get a feel for it and
assess what was going on. It seemed to ballooning in the
wind, even with full down cyclic. I kept it flying for a
couple minutes, but it was pretty tough to be precise with
it and the flight path resembled a series of stalls with a
forgiving aircraft. I recall being quite amused and laughing
out loud at this contraption. One of the stalls was a little
close to the ground and in she went. This time all 3 shear
pins did their job and everything was fine except for one of
the "rudders" breaking free and the mandatory prop break.
It's surprisingly tough! Balance is apparently very critical
with this model (think about it - no moving control
surfaces) and I'll be adding 1/4 oz. weights to the nose for
the next session.
Flight #3 Well, I wanted winds and I got
winds, hehe. They were a little strong when I pulled into
one of my flying spots, but I figured that the Rotorshape
could still have positive ground speed:) My wife Laura was
getting the camera ready and I figured that she would have
turned it on just before the launch. Basically we were in
the middle of a small field, flying "any which way' because
that's what I was expecting. The launch went well and the
autogyro seemed to have decent balance due to the fact that
it didn't baloon or dive. Controlling it in the strong winds
was a little tough, with me deciding which way to turn based
partly on which way it was insisting on going. At one point
I had it approaching along the side of the van, crosswind.
Laura was standing right beside the van ("good girl") as we
had discussed, but not watching the gyro-copter as we'd also
discussed (bad girl"), with an advisory to the effect that
"this is like an out of control heli going any which way, so
watch it at all times". As it approached I said "Laura, watch it"
Look out! Laura!, etc., three times that I'm aware of. As
this "crosswind in a gale" flight path approached the
turbulance that our van was causing by blocking the wind, I
tried steering it away from us and downwind, because my wife
was not responding or moving!. I'd already reduced throttle
(forgot) and now the poor thing peeled over and piled in on
it's side. You know what she was doing? Staring at the
camera, because it was seemingly not working :) Man, those crashes look horrible! The
plastic piece that the mast is glued into broke as did a
piece of the firewall, where the landing gear was forced
back. But you know what? The shear pins all sheared and the
rotor head popped off the mast yoke. Except for some
creative gluing, nothing broke! Oh, and the new flexible prop mount saved
the prop :) As I pieced the mast support piece back
together, I added some aircraft ply backing. The same thing
was done for the bottom half of the firewall. It's all ready
to go again! At Last! Well,,,, at last I can say that this
thing is a riot! I flew it successfully for the first time
at the Chilliwack funfly two weeks ago. We'd all watched me
make a few feeble launch attempts in light winds. Finally we
decided to have a buddy hold it like a pinwheel and run with
it to wind it up, then level it, and launch it. Is it ever
neat! I flew it lots (the most of any model I flew during
the event) and it actually won the host's trophy called
"Ron's choice". It flies pretty quickly if needed to
penetrate high winds (they eventually did come and allow
easy hand launches). At one point I sorta accidentally did
what looked like a loop. photo by Laura Peden Photo by Martin
Hunter Later on I tried another one and as it
went over the top, I exclaimed "look, a loop!", but as I
tried to pull out it just augered in straight down from
about 100 feet. Hardly any damage - BTW, it is pretty
tough..... We figured that it was rolling as I tried to pull
it out of the dive, which sorta locked it in the death
plunge. The battery was a little dented, and the shear pins
sheared and the tail needed some gluing, but that's it.
Later on I broke a two buck part that I didn't have with me
and had to stop flying it for the wseekend. I love this
silly thing!
Hand Launching:
Photo by Martin
Hunter Photo by Martin
Hunter The photos on the left show a successful
hand launch into a breeze. The blades are given a good spin
by hand and presented to the wind as shown in the first
photo. With a certain amount of wind, the blades accelerate
nicely to a speed where one can hear the pleasing blade
sound that this model has. Once that now-familiar speed of
the rotor head occurs, a hand lauch is easily done followed
by a brisk climbout. In the case of low or no winds, a
friend can be enlisted to run with it holding it like the
photo on the left. As the blades wind up and that familiar
sound is heard, the pilot can start the motor as a signal to
the helper to rotate the model level and launch it. We were
doing this in the width of the runway shown on the left.
Again, once accelerating, the blades wind right up to flying
speed.
Notes about flight performance:
The Rotorshape flies like a high wing 3
channel trainer, except for one or two things. While being
pretty fast at full throttle, it acts like a draggy aircraft
when power is reduced. Directional control is no problem,
giving precise control once you get used to it. I recall how
at first the Rotorshape was diving out of turns and then I
started giving pretty well full aft cyclic (up elevator) to
hold it level through a turn. Autorotations were tried with
mid-air restarts easily done. I turned over the sticks to
two people resulting in one pilot nervously giving the
transmitter back to me and another one letting it get away
from him and puting it into the dirt (I should have
mentioned the thing about lots of aft cyclic, hehe). I was
laughing all the way to pick it up because I knew that it
would just be a matter of replacing some shear pins. While
flying crosswind there is noticable crabbing (more than an aircraft) and of course
this isn't a problem. A touch and go can be carefully done
on short grass. However, one must not lose focus on landings
because tipovers can occur fairly easily. To land, merely
reduce throttle from the usual full-on and get a good
descent rate. Bump up the throttle a bit just before it
touches down. Dead-on into the wind is pretty well a
necessity in stiff winds. The descending glide angle is
fairly steep and there's no roll-out to speak of, so cross
runway approaches aren't too much a conern on those
high-wind days. The good news is that replacing a shear pin
or two is a minor chore easily done after having just had a
barrrel of fun! In the future I will experiment a bit with
balance to see how small changes affect flight performance.
A heavier motor could certainly be tried, allowing a ligher
battery pack to be used. A pass down the runway during those happy first flights
at Chilliwack.
Conclusion:
If you are looking for something a little
different, this rotor-winged aircraft with very simple
mechanics, and without a huge investment to complete, might
be worth adding to your stable. I was very rude to the poor
Rotorshape in the first flights and it's proven to be a lot
more durable than one might think. It builds very quickly,
with the only slightly tedious part being finishing the
blades. It's sure a head-turner and it's sure a lot of
fun! Photo by Martin
Hunter
