Flex-Wing Glider Gallery

To round out John's Glider Galleries I'll start this one for Flex-wings.

Flex-wing gliders would be any glider that use a flexable material for the aero surface of the wings. this can be the entire glider portion as is usually the case with compeititon Flex-wings. or can be Just Flip out wings and internal ejectable pod like a couple Estes and Centuri offerings over the years.
Because flexies had such an incredible advantage over all other glider configurations they earned their own competition catagory and weighting factors.
I've been trying to set a new micro flex-wing national record for the last few years but I can't get one back to calm the record even with a tiny 3" flex-wing I've had time 8 minute flights before they disappear in the clouds.

Other larger 12" -14" Flex wings made from all sorts of very light shopping bags have 4 to 10 minute flights on 1/4 and 1/2A motors.
They are super fun to watch drift away on the slightest breeze once you get them "trimmed" LOL!
Flex-wings are Super fun! if you haven't tried one you really should.

Thanks for starting this thread. Always thought flex-wings were a great idea but had heard that deployment could be inconsistent. Any tips on ballast?

Pem Tech said:

Thanks for starting this thread. Always thought flex-wings were a great idea but had heard that deployment could be inconsistent. Any tips on ballast?

Click to expand...

Actually very little Ballast or clay is needed for trimming. instead a slight Up elevator on the center spar is usually enough to smooth out most flex-wing glides.
The biggest Challange is getting the Fabric attached to the spars with the right balance tightly forward with a bit of lax aft.
Narhams used to do an almost yearly club meeting building session where we would make flexies just to help new folks get the hang of it. I have my notes and some picture of the process.
I guess I could present it here and any with questions can ask away.
Making the Flexie Springs is also sort of a fun little project with a scrap piece of 1x board and 3 finishing nail pins.


Flex-wing Glider construction: To begin you'll need a pattern. Flexies can be built with 3- 1/8" or 3/32" square spruce spars and just about any very thin light weight fabric or plastic sheeting you can find.
Many of us use 1/4mil aluminum mylar competition chute material for competition flex-wings, while others use very thin 1/2mil to about 1 mil shopping bags, Dry cleaner bag or other plastic trash bag sheetings.
Spars are connected with CA and thread to a .020"-.022" dia. custom formed music wire spring.
Spring windings MUST HAVE TWO COMPLETE TURNS around the forward pins right and left for the spring to operate properly.
Our Skeleton is then Contact cemented to the fabric over our cutting pattern seen below. Flex-Wing gliders can have just about any size and shape but two patterns have proven over time to give the best glide time results. Choose either 90° or 110° wing spread, my personal preferrence for visual effect only is 110°.

Below are a couple photos showing the materials needed to construct a Flex-wing Glider. These do not include the Booster vehicle which are usually a 3 fin BT-5 body with a very small shockcord and streamer. More on these booster tubes later....just remember "ALWAYS Fly Flexies with ejection plugs".

Back to the flex-wing glider parts. 1/8" to 3/32" square Spruce spars 12"-16" long. 1mil or thinner flex fabric. .020" dia music wire or Stainless steel music are for springs. a Flex-wing spring jig. and some light weight kevlar, nylon or carpet thread.
The last two elements are a bit of medium CA for tacking the spring to the spars. and the Most important adhesive for building Flexies! Weldwood Contact cement.

After constructing the Flex-Frame spar/spring skeleton in the shape of a
"Y" you'll masking tape the fabric tighly over your building pattern.
Apply contact cement carefully to all three spars of the frame and as thin a line along the fabric as possible following the spar lines on the pattern under the fabric.
Once dry to the touch starting with the center spar, we carefully align and attach the spars. You only get one shot at this once, the first bit of either fabric or wood making contact with the other you are committed to that location, no adjustments are possible. SUPER Care must be followed during this process.
After the center spar is in place some "fluff" can be added to the rear of the fabric by laying a couple 35mm film canisters under and between the fabric and pattern on each side of the center spar.
Keeping the fabric very taught the left or right spar is lifted up and carefully positioned along the pattern line, starting from the spring nose to wing tip, pressing the wood down as you go in the contact cement. Again Utmost care must be observed as this process progresses.
Repeat with the other forward wing spar.

As the Name imples contact cement bonds for the most part instantanously. Their may be a little creep here and there but it will not be much.
For the Flex-wing to open properly it is also important that ALL exposed Contact Cement be bonded to something even if it is only baby powder.
This is particularly true for the center spar. Make sure ALL exposed cement is De-tacked completely with talc baby powder before cutting the glider from the overlapping scrap material with a shape hobby knife.
Use a straight edge metal ruler to help guide the knife blade between rear spar tips, leaving about 1/8" outside the edges all around. These edges can be attached later to the spar or trimmed off once we are sure all creep has compeletely set.

Last is the tail notch elevator split. With the flexie still laying up side down on the table using a shape #11 hobby knife & blade, carefully notch the center spar about 2" for the tip of the tail. carefully snap this notch and apply a drop or two of medium CA to the notch holding it at about 2 or 3 degrees of up elevator. When dry you can lightly toss from shoulder height indoors to see how your flex-wing with glide. if it stalls, lower the elevator slightly or add a tiny bit of clay to the center spar. Clay is generally not required. Now you can fold the outside spars into the center spar, fold the fabric in half and half again the ONE ROLL around the 3 spar bundle for inserting into your BT-5 body launch vehicle.

I usually make my 1/4A-A BT-5 launch bodies with a 12 to 16" piece of tubing, 3- 3/32" balsa fins max of 24" of 90lb kevlar shock line and a 1" x 4" streamer. Larger BT-20 bodies or BT-50 for D flexie with a 2" x 8" streamer but not much larger remember you Want the launch body to come back quick as it MUST be returned also. Ejection Plugs of SM styrofoam are a much to protect the flexie from the Hot gasses and to ensure the glider is ejected at apogee. I usually add a 1/4sheet of FP wadding under the plug just to be safe
Storing flexies is easy with a bit of bent coat hanger or wire