(Contributed - by Frank G. Whitby - 05/17/05)
Geminee Thunder is an upscale version of the Edmonds Geminee twin glider.
As with other Edmonds gliders, the kit comes complete with detailed
instructions and well designed, precision cut balsa parts ready to be
assembled. All of the parts were in perfect condition and high quality balsa
was used throughout.
The assembly was very simple. Rob Edmonds justifiably prides himself on
producing kits comprising the minimum number of parts and requiring no
re-fitting of pieces prior to assembly. All pieces were dry fit and then glued
with very small amounts of 5-minute epoxy. The instructions suggested using
wood glue, but I did not have any on hand. I used epoxy sparingly so as to
prevent unnecessary addition of weight.
The motor mount and coupler that joins the two halves of the glider
required some careful adjustment during assembly. Alignment of the fin tips was
aided by laying out the pieces on wax paper for gluing. The instructions
recommend balancing the gliders with clay, but I could not lay my hands on any.
I used some lead shot and masking tape to weight the nose of each glider
instead. I did not measure the final constructed weight of the gliders.
The construction can be accomplished in an hour or so, but I spread out the
construction over a few days. Construction is well within the ability of novice
builders and the gliders have a very nice, stout feel to them. The biggest
problem I faced was transporting the gliders to the launch site without
inadvertently sitting on them in the car or other rough handling.
I did not paint the glider.
out of 5
The instructions suggest using a D12-3, so that is what I used. I made a small
thrust ring of masking tape and then taped the motor securely in place. The
glider boosted very nicely to 200 feet or so and separation was very near
apogee or just a bit past. The two gliders fell away from each other, began to
descend, turned gently away from each other and came back up wind in a
beautifully symmetric pair of spirals. The two gliders nearly met at the middle
of their long sloping turns and then touched down at almost exactly the same
moment about 100 feet apart traveling in opposite directions. The rear glider
snagged a 12 inch tall clump of weeds at the last moment, causing it to twist
as it hit the ground and caused the nose piece to break off. The front glider
landed gently with no damage.
The motor mount tube was badly scorched by the heat of the D motor. The tube is
crusty and slightly misshapen. I think I will have to replace it before the
next flight. The nose of the rear glider can be glued back on and should be
just fine. I think the noses of both gliders have slightly too much weight in
them, so I could probably achieve a slightly shallower and more stable glide
path if I removed a gram or so of nose weight from each glider.
½ out of 5
Construction and flight of all Edmonds kits that I have built to date have been
very satisfying. The Geminee Thunder is simple to build and would be an
excellent choice for a beginner modeler wanting to show off with a beefy
glider. It looks to me like the gliders should be able to withstand boost on an
E impulse motor, so I plan to try this next. Despite the damage to the motor
mount from the engine, the design appears to be flawless.
out of 5
(Contributed - by Hank Helmen - 01/29/06)
The Edmonds Geminee Thunder is a twin glider with a single 24mm rear engine.
The gliders are supposed to boost up on D12-3 and then separate using the
ejection charge. Glider should then circle slowly back to earth!
Included in the kit is one balsa nose cone, one balsa "plug" (to join
the glider body tubes), two 25mm body tubes, four sheets of 1/4" laser cut
balsa parts, a chunk of clay, and a 3/16" launch lug. The balsa is very
light weight (soft).
Geminee's instructions consist of two 8-1/2" X 11 notebook sized pages
black and white printed on both sides with good diagrams. I found the gliders
easy to build, but I have built many R/C airplanes and rockets before.
Instructions are OK but more information would really help this kit. The engine
mounting details and the glider testing department are lacking. There was no
instruction as to how to prepare the engine mount other than "use masking
tape to tape the engine in tightly". Also the instructions did not tell
that the engine stays in the second glider during the recovery glide, and
therefore should be test flown with a spent engine casing in place.
The instructions that are there are easy to follow. The fit of laser cut
parts is good. The only special tool that you need is a true flat surface large
enough to accommodate the 23 1/2 inch wing of this beast! I used a
vertical milling table and weighted the 1/4" balsa down to keep it
There is no guidance in the instructions as to how to paint or finish the
model. I assume this is because if you want maximum glide performance, you need
light weight. Testors spray paint or most any other typical paint will add a
whole lot of weight to these big wings and change the center of gravity
Competitive rocketeers know that painting boost gliders hinders performance so
they don't do it! I chose to give the Geminee two coats of Aerogloss clear dope
thinned 50% in order to give it more strength and help protect it from wet
grass, etc. I also used bright permanent markers to aid in tracking and
recovery. There are no decals in the kit. Titebond yellow carpenters glue was
used for wing and fin joining.
½ out of 5
The only recommended motor is the D12-3. Preparation is easy, just stick the
engine in and insert your igniter. No wadding is required.
On my first and only launch the gliders began straight on lift off but
after about 40 feet up began to arch over toward St. Louis! Under full engine
power the Geminee nosed straight down into terra firma! The engine then ejected
with a very sharp and loud "boom!" The engine casing may have flown
higher than the gliders! I used a 24mm C11-3 for the first flight. I'm not sure
if this affected the flight. Perhaps the D12 would have accelerated faster and
given a straight boost? I dunno. Once again there are no troubleshooting flight
tips in the instructions such as what type of launch rod to use or what size
engine not to use, etc.
There is no shock chord on this model. All of the balsa is very lightweight
Luckily the ground was soft from recent rain and the only damage was that
the nose cone was pushed in flush with the front body tube along with a lot of
thinking that I should have used a larger diameter and perhaps longer launch
rod. I used only a 36" long 1/8" diameter rod. I think this thing
needs to get some speed up for dynamic stability before letting it go free.
For some reason I took the upper glider and gave it a "test
glide" after pulling it out of the dirt. The forward part of the fuselage
snapped in two where it joins the body tube on landing again, right along the
grain. This was the second or third time this had happened. Repair was easy and
I plan to fly this thing again as soon as we get a calm day and I have the
out of 5
This is a pretty good kit but it needs some improvement in the instructions
department. The main PRO of the Geminee Thunder is of course its size and
excitement of twin gliders floating down.
The CONs are that the instructions should give more information on test
gliding in tall grass to verify center of gravity of each glider. They also
need more information on how the engine should be mounted and how the glider
uses the ejection charge to separate therefore the engine must remain in
place during the entire flight. The fuselage balsa should to be stronger, I
have used 1/2" Carbon Fiber Laminate "tape" from Hobby Lobby
International to reinforce my fuselage sides where they join the glider body
out of 5