900MM DLG glider at 182 grams with ailerons900MM DLG glider at 182 grams with ailerons
Aug 08 2012
Well this is version 5 of my DLG builds. You've only seen 2 other versions here on FaTedev as the 2 after failed so badly I didn't even bother to try fly them. However I decided to dump the solid balsa wing and go for a composite of depron and balsa and also increased my wingspan.
I used 3MM depron for the wing core, sanded as a round edge on the leading edge and a gradual slope off like a typical Clark profile.
Using 2MM balsa wood I used Velpron mount board spray to bond it on the bottom of the wing then used weights to hold it while drying.
The wing already is more rigid that just depron. It's exactly 10CM wide by 90CM span.
To make the wing even more rigid I added a 2MM carbon fibre rod across the entire span which also my throw peg will bond too.
Now the top balsa is also bonded using the same method, except because of the shape I used a towel between weights and wing top.
54 grams and the wing is not sanded or treated yet.
I used thin epoxy to coat the wing and tail and wiped off all excess.
Now all the surfaces are sanded they weigh in at 76 grams but I'm super happy with how strong they are.
The wing mount has 2 nuts inside for nylon bolts. I embedded them inside a hardwood core then used regular balsa on top and bottom. Over that goes fibre glass epoxied.
Can see how the bolt fits in, note the cut out in corner for aileron servo.
A better view of how the aileron servo fits in.
The wing bolted onto the fuselage and it's totally secure and rock solid. I am not worried about transfer stress on the fuselage from throwing at all.
Like DLG version 3 I decided to direct solder all components direct to the RfSky FRF4 RX unit. Saves space and weight having no plugs.
I used a piece of 2MM ply wood to make the base of the nose then epoxied another piece to sandwich the carbon rod.
Now I can start to get a feel for a final weight but still not finished. 139 grams so far.
I used a block of balsa on the nose and sanded it too shape then used 2MM balsa to make sides.
Mock up of the lipo fitting it's quite snug but it does have a velcro patch also.
I skipped how I did control lines as I repeat the same process using carbon fibre rods and heat-shrink pipe in every project.
Seeing as most of the parts are Chinese I dubbed it fate but in Chinese, along side is the Netherlands flag.
Opposite wing side is the English tag and FrSky-RC decals which show up really nice on balsa.
Now to re-enforce the nose with fibre glass wrapped around it. I used CA glue to bond it, was smelly but it's like a rock.
The sides also are covered from the same piece of cloth to make them very solid for only being 2MM thick.
Now all sanded down and smooth I got a first look of the whole balsa looking model and I like it.
I required 21 grams of lead to balance COG so I put them under the nose and left it bare for it's maiden so I can tweak.
Finally on the scales with lipo so All Up Weight (AUW) showing 182 grams. My limit I set myself was 250<>300 grams so I am well below that. Overall it took about (EXCLUDING epoxy dry time) 8 hours to build this model in total which I think is pretty good for the result. Now for the maiden!

It was getting really dark before the wind complied so did a few throws and found it does fly but needs trimming and maybe a little more nose weight for launching.
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