Pictures of the Building of a Gulp


GULP Assembly
by Greg Smith

Here are some pix and descriptions of the building of the GULP. The instructions that came with the kit are complete enough that if you have built planes before you should have no problem. This was my first foamie so some of the techniques were a bit new but presented no problem.

This was the contents of my kit. Steve Drake offers a couple levels of completeness depending on what you have lying around the shop. I went for the middle kit that includes the carbon spars, elevons and a bit of glass. The rest of the supplies I either had or my trusty hobby shop, Greenfield News and Hobby had. Notice that beautifully shaped fuselage? It comes like that!

See that stringy stuff left over from the cut? Get rid of it!
After I did that I routed out the spar channels.
Update: The Gulp now comes with routed spar channels.

Per Steve’s plans I raised each tip panel 3/4″. I used the lower core beds to keep it level. I joined the two wing halves with epoxy. Then I joined the carbon spars to make a one piece top and one piece bottom spars and got the correct dihedral in them by laying them in the previously routed out channel. I wrapped a couple of layers of carbon cloth around the joint between the left and right sides and epoxied them together. I put a bit of Saran-Wrap where the epoxy joint is and pulled out the spar when the epoxy set up. I then glued the whole spar in with Goop. Makes a nice stiff wing.

Here is the bonding of the sub-trailing edge. I used Goop here too.

Here is the Carbon cloth I used to laminate to the elevons in a vacuum bag. If you don’t have a bag, Steve’s deluxe kit has all the materials and a way to do the laminating without using a vacuum bag.

Here they are fresh out of the bag. They are very stiff and look cool too. This is good because I plan to DS the heck out of this thing. I am also using strip aileron controls to keep all the moving bits inside the fuse.

Honey, what the heck is that in the oven. Well dear, you see, the ballast tube needed a bit of post curing for extra strength.

After I routed out the ballast area I Gooped in the ballast tube. I made the tube from some carbon fiber sleeve that I got from CST. I used a piece of 1/2″ PVC electrical conduit as a former, waxed the heck out of it, slathered on some epoxy, wrapped it with peel-ply and paper towel and stuck it in the vacuum bag. I took longer to write this than to do it and it is a super strong tube!

I cut this piece off so I can load it like a shot gun. I’ll put that cover on when it is loaded.

Here is a shot of the servo install. This is on the bottom of the wing. The center 2 inches is covered with glass and epoxy. The strip aileron controls are shown at the bottom of the picture.

Doing some taping. Pretty standard for EPP planes. Over the spar is 3M fiberglass reinforced strapping tape as well as the Sub trailing edge. The leading edge up to the spar tape is covered with a new 3M “Extreme Condition” reinforced tape.

Ready to join the parts. The battery and receiver are stuffed in a hole made by hogging out the area in the fuse in front of the wing. The lower part of the wing saddle area was relieved to accommodate the servo arms and the linkage to the strip aileron controls. I gooped the wing and fuse together. I also gooped the vertical fin on and then covered the fuse with 3M strapping tape from front to back. All that remained was to cover the bird in Ultracote and attach the elevons.
See the finished product on the main GULP page.

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