Introduction
The Stinger's 84" wingspan is 7 feet of flying fun!With its 84" wingspan, our super popular, IMAA-legal Stinger kit is built
for giant-scale fun. Super-strong "no-joint" plywood fuse is built-up on the
bottom and features an ABS turtledeck above the wing. The giant foam wing (nearly 1,600
square inches of wing area!) features a fully-symmetrical airfoil, full-length ailerons
for added maneuverability, and balsa spars for added strength. Complete plans,
instructions and preformed landing gear included; 4-channel radio and 1.2 - 4.2 cu. in.
engine required.

REVIEW:
Construction
The Stinger arrived in a LARGE box due to the foam wings.
The kit was well packaged with the foam wing cores still in the shroud that
they were cut from. The wood throughout the kit was acceptable and none had to be
replaced. The plastic (ABS) parts were accurately formed and, when cut on the scribed
lines, required almost no further trimming. The canopy was very clear and defect free. All
ABS parts are fiberglassed inside (I glassed the cowl inside AND out due to the
anticipated vibration from the Zenoah G-62 engine I used).
Assembly of the kit progressed rapidly, and the plans were followed with
only a few exceptions (noted below). The foam wing cores are covered with balsa sheeting
at both the leading and trailing edges. Between these sheetings are cap strips that serve
no purpose other then to support the wing covering (Monocote). The wing halves are joined
with a hefty plywood spar, balsa top and bottom, then fiberglassed over the center
section. I recommend putting more of a bull-nose on the leading edge of the wing than is
called for in the plans. Flying proved to be too sensitive in the pitch attitude until I
rounded the leading edge.
The tail grouping is made up of 3/8" square balsa sticks - no
sheeting. Hardwood dowels are used at all flying wire attach points and at the control
horn points. The plans call for using quick links, bending them at a 45 degree angle, then
enlarging the hole to fit 2-56 hardware. These are then soldered to piano wire. There are
a couple of tricks to making this happen. First, don't try to bend a sharp 45 degree
angle. Just make it a nice gradual bend, otherwise the tempered steel will break. To drill
the holes, use a sharp .085" drill bit and turn it slowly in your drill press, using
lots of oil. You'll only be able to drill a few at a time without resharpening the bit.
Also, instead of using the aluminum joiner under the fuselage to connect the flying wires
together, I made a joiner out of fiberglass. This breaks up the diamond shaped flying
wires electrically that can act as an RF shield to your radio antenna VERY
IMPORTANT!
NEWS FLASH!
I just changed the tail wires mentioned above. It worked fine, but seemed really
heavy compared to someone else's tails section at a scale meet I attended recently. I
replaced the piano wire with rigging wire. Much lighter, just as strong, and looks better.
The plans didnt call for any fiberglass in the firewall area. I
have heard from other Stinger builders that in some cases the engine actually departed
company from the fuselage! Not interested in this happening to mine, I glassed the nose
pretty well. I also had to make a slight modification to the firewall as I used the
pitts-style Slimline muffler. Overall, the G-62 fit very nicely on this plane.
I highly recommend the wheel pant modification
that was developed to insure a much more secure mounting of the wheel pants!
For the radio gear, I used my already proven JR XF-622. I put a ¼ scale
servo on each aileron as recommended in the plans, and a ¼ scale servo at each elevator
half. Another ¼ scale servo powered the rudder, and a standard servo for the throttle.
The rudder and elevator servos were mounted in the tail. All this was powered by two separate battery packs and two switches. Redundancy in this
area is a small price to pay for the added insurance. I also kept a 10" distance
between the engine and all radio gear to minimize interference, and used nyrod for the
throttle pushrod.
I found that the ailerons needed a 1/16" balsa sheet laminated to
them in order to get the same thickness as the wings trailing edge. This is no big
deal and Im sure has no actual affect on flying characteristics; I just like the
look of the ailerons matching the wing. I used the recommended Robart hinge points
throughout. I applied a bit of Vaseline to the hinge joint, then epoxied one end in and
let it set up. When cured, I applied 30 minute epoxy to the other ends and installed the
surfaces, taking care to remove all excess epoxy in the joint.
Since my color scheme was black with silver trim, I wanted to canopy to
blend in and used navy blue Rit dye. For those of you unfamiliar with this, just immerse
the canopy in the dye at a temperature of about 150 degrees F. until the desired tint is
achieved.
Flying
Well, it all comes down to this, doesnt it? A few days after my pride and joy was
finished, I carefully loaded it into the pickup and headed for the local flying field for
its maiden flight. After running it up and taxiing it out, I lined her up with the
runway and poured the coals to it. The tail lifted up nicely and executed a smooth,
straight climb out. The only surprise was that down elevator was a bit sensitive. All
other control responses were what was expected. I used the recommended control surface
throws as indicated on the plans.
This is a very smooth flying plane with no known bad habits. It is much
more graceful than the smaller birds I had been flying (this was my first stab at giant
scale). The G-62, as promised by other modelers, is extremely reliable and forgiving to
variables in carburetor settings, fuel tank location, etc.
All in all, this is a great plane to ease into giant scale modeling!
UPDATE - 10/2
After flying the Stinger for over a year, I decided to give it a 'lightening'
overhaul. This is amounting to a reduction of over FOUR POUNDS! Heres
how. I removed the following items permanently:
Spinner
Gas hatch cover
Canopy hatch
Turtle deck
Wheel pants
Cowl
Spring starter
Extra 5-cell battery
Giant scale servos
¼-20 steel wing hold down bolts
MISC
In addition, Ive always hated the flying wires on the tail! So, off with the tail
feathers. Theyll be replaced with foam/balsa. The top rear fuselage is now covered
with 3/32" balsa. Just a flat top no turtle deck look.
So, yes, the finished plane wont look as nice as the original Stinger, but this
is a test to compare performance and flight characteristics with a significant
weight reduction.
ENGINE MOD
I purchased a C&H Electronics Jump Start. This is an electronic device
that allows you to hand start the G-62 without the aid of a spring starter. It just
retards the spark for starting, then you disconnect the battery and go fly. The advantage
of this over true electronic ignition is that you dont have to carry the battery
weight. It all adds up! Bench tests show that itll be great. It's a $65 unit.
NEW WING
I'm building a whole new wing as the original wing had been through several mild crashes
and it was time to experiment. This now one is a honeycomb foam with 3/32"
solid balsa sheeting. The holes are 2 1/2" diameter - 99 holes per wing
panel. Yep, that's 198 holes in the wing!
Ill use ProBond Polyurethane for the adhesive. If youve ever
used this stuff, you know its the only way to sheet foam wings! No spars, no
dihedral brace, no nothing. This wing will not have the notch in the center leading edge.
Im expecting a much stronger wing at the same weight as the old one. See the
Wing Update below. Balsa was purchased from Dynamic Balsa and was of very high quality. Straight and
light. I didnt go with contest balsa, but what they sent me was fine for my
purposes.
Drilling the 2 ½" diameter holes in the wing cores resulted
in a weight reduction of 12 oz. Each wing core weighed 12 oz prior to coring and 6 oz
after. Not bad. Drilling was performed on a drill press with very nice results and a VERY
MESSY SHOP!
WING UPDATE 11/15
Man, is that thing STRONG! I glassed the center 10" with 4 oz. glass all the way
around. Supporting the wing tips on blocks of wood and pressing down hard on the center
results in zero flex. The old wing flexed maybe 3/4". Weight is the same as the
original - 60 oz. I like this new wing better because it is stronger, truer and fully
sheeted for better appearance and better integrity. Ailerons are now built-up and sheeted
with 3/32" balsa instead of the solid sticks that come with the kit. They are also a
little wider than the originals. It always seemed to me that I need a bit more aileron
authority. This should help.
TAIL FEATHERS UPDATE 11/29
The foam/balsa tail is finished and mounted on the fuselage. They are EXTREMELY strong!
Like the wing, they were sheeted using Probond Polyurethane. After they were mounted, I
glassed them to the fuse and to each other - top and bottom. This is a bullet-proof tail.
It's still very light.
COVERING IN PROGRESS 12/2
I'm in the process of covering the Stinger with Monokote. I'll be using Hitec 605 servos
on 6 volts on all surfaces - one on each elevator and one on each aileron. I'm starting
off with one on rudder, but will probably have to add another in pull/pull.
TEST FLIGHT 1/1/2000
I test flew the new Stinger for the first time today and it went real well. I could
definitely feel the difference between the 20 lb. version and this new one at 16 lbs.
Takeoff roll is practically nonexistent. It hovers at half throttle and
accelerates vertically from the hover. Landings are noticeably slower and more
gentle. It also likes to float, and float and float when coming in for a landing.
The only down side is that it isn't as stable in wind as it used to be. Wing
loading went from 29 to 23 oz/sq. ft.
The C&H Jump Start works GREAT on the G-62. It's so nice getting rid of that
heavy spring starter and crankshaft drag!
I'll probably throw in a B&B smoke system one of these days for something new to
try. This new plane certainly has the carrying capacity for the added weight now!
Review by:
Bill , Tucson, AZ |