Phil_G wrote: ↑06 Nov 2020, 22:04
Nick, if its not too late, can you continue the build photos with the ZG wing construction please?
I'm intrigued as to how you build them so quickly and accurately with next to zero weight
Eg do you pre-curve the top sheet? how? L/E and T/E? Root joining?
Ta
Phil
These the parts for the wing - though haven't quite decided how to do it yet...
Phil asked about the build process..
This picture is a Wizard of Oz tailplane 14 inches - and is the simplest form of wing / tailplane ie ribs, no spars
This works fine - but you need to have fairly frequent ribs - and for them to have a reasonable camber. It's the camber that stops the wing folding - if the depron is just flat it bends easily
This is (half) a depron wing - 18 inches
I covered it in A3 doculam (laminating plastic) which explains the shine - tips not covered
This the original and a higher aspect ratio version - 21 inches
I use a small piece of an aluminium arrow as a tube and carbon fibre arrow repair tubes as a wing joiner - not a good photo but usually 1/3 back from L/E
On larger wings I use two joiners. If I use two joiners I make one longer so that if I feel like it it can become a wingeron wing
The underside can be made in different ways - mostly depending on how strong you want it to be
This has 6mm ribs (which go in first) - then longitudinal spacers. I tried some cross bracing with dental floss - didn't seem to make much difference but strong stuff.
Doculam on root half of the wing+ on top and bottom - which makes things very strong.
One wing half is 22gm
This the higher aspect version - 6mm ribs at root and 2mm outboard. Doculam on top and bottom which makes it really pretty strong. Not had a wing fold and have flown these a lot
One wing half is 22 gm (remember it's the hot glue that is heavy, not the depron. This wing bigger than the other wing which also weighs 22gm
On my 50 in Zeitgeists one has 2mm depron top and bottom and no spars - very strong if ribs are properly spaced - and really quick to build.
The other 50 in wing I made out of 6mm depron instead of balsa / covered in Solarfilm. I don't recommend it - no real advantage and
really hard to avoiding melting the hot glue and building in unwanted warps when you shrink the Solarfilm
The video of the Zeitgeist earlier is also a top and bottom sheet / 6mm fuz - I often make 2mm - but again the hot glue is the real weight
Build order is counterintuitive!
Mark out the rib position on the UPPER wing - biro is good
Put depron on rounded edge of a table and place two open hands. Roll the depron forwards and back - a combination of hand heat and rounded edge of table works fine. You can steam over a kettle / bind and pour boiling water but I can't be bothered.
You may get some longitudinal crinkles on the concave surface and this makes no difference - avoid rib-wise crinkles - you set yourself up for a 'hand clap' wing
Now glue / spot glue ribs in place taking care that the L/E lines up accurately, T/E not the issue
You can add a carbon fibre leading edge but not actually necessary. Sometimes it's helpful for the profile at the L/E but remember to cut an appropriate hole when you make the ribs (much quicker)
Now add the bottom surface - spot tacking is the way to go, starting in the middle lengthwise and spanwise.
Work your way along the span tacking at front / back of each rib - don't glue L/E at this stage
You would think it's easy to build in a twist at this stage but because of the top surface is cambered this doesn't happen
The last stage needs some (but not a lot) of care!
Makes sure the glue gun is really hot - the joining of tom and bottom surfaces is helped by thermoforming with the hot glue.
Start in the middle and only glue the LE between two ribs at a time
Work your way to root / tip alternately
The hot glue is extremely strong and you will end up with a surprisingly strong LE - if you don't believe me make a line of hot glue, let it solidify and then try to break it....
Key idea is that if you have no bottom surface make sure there is a reasonable camber. Doculam is cheap and very strong but don't overdo the heat or you will remelt the hot glue and at that stage you can build in a warp
2mm depron now hard to come by - 3mm is fine
I've been making 2mm correx wings as well (see Wizard of Oz) and might try a Zeitgeist one - black Correx with 'Jewson' repeated at intervals....
I have just made a jedelsky-winged power glider out of an estate agent board and it's a 20 second speeded up video if you are really bored. Haven't flown it yet but previous versions have worked well
Centre sections are better with a lower depron surface so it sits on the fuz, add c/f at L/E and T/E to avoid rubber band damage
Tailplanes are an easy build - either 2mm c/f on L/E but better inset 1/3 back and 2/3 span seems to work fine
A short novel more than a build log...