VISIT THE GLIDER WORKSHOP COMPANY STORE TO PURCHASE YOUR CHUCK GULLS
Arguably one of the most beautiful aircraft ever built is the gull-wing glider. During the 1930's gull-wing gliders were the state of the art, with Germany leading their development. Due to provisions resulting from WW1, Germany was unable for many years to design and manufacture powered aircraft - hence their focus on gliders and sailplanes.
We've selected three vintage gulls from this golden period of design and experimentation for our Chuck Gulls Kit; two American designed gliders - the Lawrence Tech LT-IV and the Ross Stephens RS-1, and a German gull, the DFS Reiher III. These are a great father/son/daughter build project and they fly quite nicely. Due to the gull construction of the wings - this kit is probably a little advanced for unsupervised kids. We recommend that dad build the first one with the kids watching, the kids help build the next one and then let the kids build the last one.
Follow the instructions below to build your gulls. Each photo can be clicked upon and opened for an enlarged view and make sure you download the PDF of the Gull Build Tips. Have fun!
LAWRENCE TECH LT-IV
TIPS FOR BUILDING THE CHUCK GULLS
The first thing to do is download and read the "tips" file below and familiarize yourself with the build photos and instructions.
Click the image above to open up a larger version of the "Tips".
Click Download Chuck gull plans_tips to download a PDF version of "Tips"
THE FINISHED DFS REIHER III
BUILDING THE CHUCK GULLS
All three Chuck Gulls build the same way so this build log will demonstrate a build of the DFS Reiher III. The only tricky part in building the gulls are the wings due to the breaks in the wing (called dihedral) that gives it it's distinctive gull shape. Use the "Build Tips" mentioned above along with the build photos and narrative below to build your Chuck Gulls.
Step 1. Arrange all the parts by gull. You will notice that each part has a letter and a number etched into it. The Reiher is "R", Ross Stephens is "RS" and the LT-IV is "L". The numbers identify each individual part in relation to the total number of parts for the glider. So R-O1-14 means Reiher part number 1 of 14 total parts. Make sure you have all the parts for your gliders.
Step 2. Select the glider you'd like to build first. They all build the same way so it doesn't matter which you select first. Lay out the parts as indicated below to get a feel for how everything goes together.
Step 3. Collect your tools.
- Glue, most any type of wood glue will work.
- Sharp modeling knife such as an Xacto knife.
- Ruler that can measure down to 1/16”.
- Medium to fine sandpaper, about 220 grit.
- Wax paper or Saran
- Building surface - anything flat and that can be cut on, magazine, cork board, etc...
Step 4. Locate the dihedral tenons. Carefully remove them using an Xacto blade to cut them out. Notice that there are two different tenon sets. The set of two are for the fuselage the set of four are for the wing panels. Do not get these mixed up.
Step 5. Locate the wing panels. There is an inner and outer panel for each wing. The inner panel connects to the fuselage. Make sure you orient the panels as shown below with the bottom of the wing panels on top of your work surface. You will be doing all of the wing joining on the bottom surface of the panels. The photo below shows the inner and outer panels, bottom side up, with two tenons located at the point at which they will join the two panels.
Step 6. Using an Xacto blade and sandpaper carefully make a channels for the tenons. There are marks laser etched into the wing panels showing where the channels should be made. The wing panels are 1/8" thick, the tenons are 1/16" thick. Make sure your channel is 1/16" of deep. Be careful not to breakthrough the top side of the wing panels. The easiest way to do this is to use your blade to make cuts that are the length of the channel and make each cut as close as you can to the other. So you end up with many slivers that you can then use the end of your blade to to remove. Alternativle use a small file to carefully sand the channel. Use your sand paper to clean up the channel.
Step 7. The photo below shows how the tenons should fit into the channels. Click the photo for a close-up view.
Step 8. Repeat the channeling process on all the wing panels
Step 9. With the channels cut in the wing panels the next step is to rough sand all of the glider parts. You want to create the shapes and airfoils shown in the build tips. We do the rough sand prior to gluing the parts together.
Step 10. Now we will sand in the correct dihedral angle or bevel into the wing panel edges. This is a bevel that allows the two panel surfaces to mate at the seam not leaving any gap. This is the most complicated part of the build in that you have to visualize how the wing panels will go together in order to make sure you sand the correct angle in the panel edge. The easiest way to do this is to tilt the outboard tip of the outboard wing panel up 3/4". The blue tape role is 3/4" thick. Then GENTLY sand in a bevel at the root edge of the outer wing panel using a block of wood in order to make sure you get a bevel that is perpindicular to the build service. Do not bevel the outboard edge of the inner wing panel. Only bevel one edge of the two edges that will be glued together. Repeat this for the other outer wing panel.
Step 11. We will now repeat the beveling process for the inboard edge of the inner wing panel. Once again tilt the outboard edge up on a 3/4" block and lightly sand the bevel using a block to maintain a perpindicular edge to your build surface. This is the edge that will mate to the fuselage side. It is critical that you visualize this first in order to properly orient the edge for beveling. If you make a mistake don't worry, you can always sand in a new bevel. Just make sure to you keep the wing panels the same lengths if you do need to resand a bevel.
Step 12. Now we will begin gluing the parts together. We use Titebond III but any good wood glue will do. We don't recommend using CA or other super glue because it does not give you the chance to fiddle with the parts as they dry. You're going to start by gluing the wing panels together observing that you have the bevel/dihedral angle correct before joining the two parts.
Step 13. Coat the edge of one wing panel with wood glue.
Step 14. Once you have applied glue to the edge of the wing panel then pin it in place on your building board at the correct dihedral angle. Make sure the wing panel joint is tight. Next you're going to place glue in the channels and lay in the tenons, gently pressing them into place.
Step 15. When the wing panel joint and tenons are dry you are now going to glue in the tenons that will pass through the fuselage and connect the two wings. Once again pay very close attention to the orientation of the wing and the tenons relative to the fuselage.
Closer view of the fuselage tenons
Step 16. Prep the fuselage openings for the fuselage tenons. Carefully shape the holes to the tenon shape so they fit snugly.
Detail of fuselage tenon holes.
Detail of tenons.
Detail of tenons.
Detail of tenons.
Step 17. Glue the wing assembly to the fuselage. The easiest way to do this is to coat the edge of the inboard wing panel and half of the tenon that sits inside the fuselage with glue. Then hold it whil it sets making sure that you maintain the proper dihedral.
Detail of tenons after gluing the first wing assembly in place..
Step 18. Gluing the two wings to the fuselage is next. This is the most difficult part of the build. Take the remaining wing assembly and fit the channels you created previously onto the tenons that are projecting from the fuselage. The tenons will provide a close fit for dihedral and orientation. When satisfied with the fit then apply glue to the edge of the wing panel and the tenons extending from the fuselage. Then press the assembly with your thumbs making sure you maintain proper orientation and dihedral. You will want to check the orientation from head-on a few times while the glue is drying making sure nothing has moved. Wait for the glue to set.
Detail of wing assembly.
Detail of wing assembly.
Step 19. Root fairing fillets. There are four 1/16" pieces which "sandwich" the wing assemblies at the fuselage. Two on top two on the bottom. These are called fillets and their purpose is to provide for a stronger and more durable mating surface between wing and fuselage. Apply glue to the bottom and the edge which mates with the fuselage then press into place. Note the proper oreintation of the fairing as far as its contour.
Wing fairing fillet detail.
Wing root fairing detail
Step 20. There are 4 small 1/8" fillet that fit between the fairings. Glue these in place once the root fairings are in place. These small fillets will project out the end of the wings. You will be sanding these down to contour the wing once you start final sanding.
Detail of the wing root fairings and fillets.
Step 21. The last few steps are simple. Glue the elevator and rudder parts into place making sure that these parts are horizontally and vertically aligned with the fuselage. Use wood glue again for these parts so that you can fiddle with them as they dry should the move out of alignment.
Tail group detail.
Step 22. Final sanding. All the parts have been glued together. It is now time for final sanding. Use the suggestions in the "build tips" to help guide your sanding. Pay close attention to the wing tips and trailing edges. You want the wing tips to be as thin as possible and the trailing edges should be as thin as possible. The thickest part of the wing is at the fuselage - the wing profile feathers out to the wing tip. The less weight you have in the wing tips the better the glider will fly. Also the leading edge of the wings are rounded while the trailing edges should have a "knife point". The wings are 1/8" balsa so you can remove a lot of balsa in order to get the proper profile.
Sanding the wing root fairings and fillets should be done carefully. You want the wing root to blend in to the fuselage. Consider masking the sides of the fuselage and and the wings with tape in order to prevent gouging or denting as you sand the fairings and fillets. Take your time with this.
The fuselage and and tail parts just need to be gently sanded with the edges rounded.
This is what you're shooting for:
Trimming and flying the Chuck Gulls
Read the "Build Tips" for suggestions on how to best trim your gulls for flying. I have had several nice flights with my prototypes. You can trim the gulls for two types of flights - first, just a straight glide, and second, you can "warp" the tail sections to create an upward spiral that will allow you to catch a thermal. I have even used very light guage wire like the kind in a bread "twisty" to fashion hinges for the rudder and elevator.
The best conditions to fly your gulls in are a gentle breeze and slight downward slope. Gently toss your gull into the breeze and watch it take off. It is also fun to find a slope or a hill and toss it off - again into a slight breeeze. This is where the young'uns come in handy so they can run down and fetch the gulls back up to the top of the hill.
I hope you enjoy building and flying the gulls. Please send a picture of your completed gulls and we'll post it here on the build log.