LEG Guppy Review
Jack Cooper of Lead Edge Gliders has introduced a new kit, a 48” wingspan acrobatic glider called the Guppy. This little guy is a scaled down version of “Le Fish” a VTPR style acrobatic glider designed by Steve Lange (AKA Surfimp) and also kitted by LEG.
The Guppy kit I received was very nice. The EPP wings and fuse were beautifully cut, as were the balsa parts. The hardware package is complete and of good quality.
As typical of Jack’s kits, the the two piece “profile cut”
fuse is shaped and then split open to install the electronics and carbon tube
longerons. I used a small AAA receiver pack and two HS85MG’s in the fuse (rudder
and elevator). The Golden Rods were inlayed into the surface to the fuse (instead
of inside as per the usual LEG build). The wing uses a ribbon spar. A nice slot
has already been cut (in the bottom of the wing?). The wing uses a spruce drag
spar but no additional balsa TE pieces. I used the Chris Klick “No Tape”
method to reinforce the fuse and wing (Roofing tape and 3-M 90) but the standard
fiberglass tape would work well too.
I covered the plane with Ultracote. The ailerons and tail control surfaces
are taped on… like a combat wing.
The CG was balanced to 1 7/8 inches back from the LE (currently at 2”).
My flying weight is 21 ounces. I set the radio up for 4-axis flying (snap flaps
and flaperons on the throttle stick). A more complete build thread with additional
photos can be found here: http://www.rcgroups.com/forums/showthread.php?t=670371
Flying the Guppy
My first flight was in windy gusty conditions. However the Guppy flew straight
and level right out of my hand. I had to work a little to get her out of the
horizontal wind and turbulence close to the cliff edge, but she penetrated very
well for a 21 oz plane. Once I was into the lift… Woo Hoo! She showed good
speed, tracked very well, flew inverted great and had a fast roll rate. She
felt a lot like a combat wing… light and maneuverable. She did everything
I would want in an acrobatic glider… similar to Le Fish, just at a faster
My second flight with the Guppy was in lighter “slermal” conditions
on low angle site (cinder cone). I enjoyed making low speed runs and doing loops
and hammerheads that pulled out close to the ground. I had quite a few light
crashes with little damage. I was able to catch thermals and ride them way up.
I soon learned that the Guppy will get into a spin easily (both positive and
negative) that will flatten out nicely in a couple turns. Recovery was simple.
Let go of the sticks, and in a half a turn or so you were in a nice down line.
In soft conditions or during lulls, it is easy to over control this plane
and get the Guppy to fall out of the sky (typical of small high performance
gliders). Dual rates are a good idea. I have set up a “thermal” flight
phase so I can hit a switch and instantly have reduced throws, aileron/rudder
coupling, and optimal wing camber set, making it easy to float around and wait
for the lift to pick up.
The third flight was in moderate wind on a steep slope. I am starting to be
convinced that little guy does not want to go slow. It would much rather be
in good lift, flying fast, cranking turns and doing tight acrobatic maneuvers
(see altitude note below). I am also noticing that I am not using the “flapperons
on the throttle” much. “Snap flaps” is all I need (and they work
very well). This glider turns, point rolls and knife edge with little or no
rudder. The rudder is useful of course at slower speeds and for nice hammerheads,
“shark” turns, snap rolls, spins etc.
Many folks will want to know how the Guppy compares to its bigger brother
The Guppy looks faster and more “frantic” in flight. It has a
quicker roll rate and it likes to loop tighter. It does not fly as smooth and
gets bounced around more in turbulent air. It flew outside maneuvers slightly
less well as Le Fish (I need to check the tail incidence and tune the snap flap
setting more carefully to make sure I have everything set up correctly.) The
snap rolls are more violent and quicker to recover (deep snaps looked like tumbles).
Spins are quicker to enter and spin faster… but still get nice and flat. “Blender”
style spins (vertical roll on the downline to a outside snap/spin) are particularly
quick and dramatic. Point rolls and knife edge is easier with the Guppy, needing
less rudder to compensate. My Le Fish tends to pull a bit to the belly on knife
edge, Le Gup pulls slightly to the canopy. The Guppy did not have as much momentum
to play with. However it will do nice pumps and can get a couple rolls on the
way up. The Guppy gets smaller quicker… and as a result is harder to see at
a distance. For either plane, I think you should try to build light. My Le Guppy
weighs 21 ounces– similar to my combat wings. My Le Fish is 37 oz.
So the bottom line? The Guppy is an easy to build, durable, highly acrobatic
glider. It is not a beginner plane, but if you have some flying skills and like
to get crazy, the Guppy will do all the acro your thumbs can handle. For folks
that have access to a slope with decent lift, I think the Guppy may be the ideal
“in your face” plane. It has a high “fun factor” like
a Weasel with much better outside ability (though not nearly as good in light
air). It will “crank and bank” like a combat wing with the added
fun of being able to do “real” acrobatics… including crisp snap
rolls, spins, knife edge and more (durable, but not as “crash-able”).
I love this little guy. I won’t leave home without it.
Congratulations to Jack for another great kit.
* Please note that I fly at altitude, mostly 6000-9000 feet.
In our thin (low lift/drag air) planes need to fly a bit
faster and/or need a bit more lift. The Guppy’s light air
and slow speed performance may be better at sea level.