Zeitgeist - s/c and galloping ghost

They stay up by magic!
MJF
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Joined: 12 Jun 2018, 15:22
Location: Ontario Canada

Re: Zeitgeist - s/c and galloping ghost

Post by MJF »

It is not the medium that matters it is the skill and creativity and your glider construction shows both.
Very nice.
Nick M
Posts: 92
Joined: 19 Dec 2018, 20:39
Location: Camberwell london

Re: Zeitgeist - s/c and galloping ghost

Post by Nick M »

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 :D
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...
zeit wing parts.jpg
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
WoZ tail.jpg
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
wing 1.jpg
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
wing 2.jpg
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

wing 3.jpg
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
wing 4.jpg
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
wing 5.jpg

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...
Martin
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Joined: 16 Feb 2018, 14:11
Location: Warwickshire

Re: Zeitgeist - s/c and galloping ghost

Post by Martin »

A friend, Tony, forms the curves in his depron wings, and other depron parts, using the top rounded edge of a central heating radiator. He says the heat of the radiator makes forming the curves easier.
I've never seen him do it - I would have thought the wall would get in the way - but perhaps he has a radiator next to a window, or something.
Nick M
Posts: 92
Joined: 19 Dec 2018, 20:39
Location: Camberwell london

Re: Zeitgeist - s/c and galloping ghost

Post by Nick M »

Genius idea about the radiators - I'll try and find a convenient one with a bit of space

Built the wing this morning - but didn't have enough ribs so used some wrong sized ones as building time on the kitchen table is limited...

This one underside
wing.jpg

This topside
wing both.jpg

I'll sheet undersides where meets the fuz and add some c/f to avoid rubber bands cutting through the depron

I'll cover with doculam - which will be up to a full width rib - might need reinforcing as the doculam will shrink
Nick M
Posts: 92
Joined: 19 Dec 2018, 20:39
Location: Camberwell london

Re: Zeitgeist - s/c and galloping ghost

Post by Nick M »

These three existing fuselages - radio going in the current build next w/e + tailplane / rudder
fuz.jpg
All fuz are +/- 31 inches

The lightest fuz is 44g with radio and no lipo - rudder is using dental floss lines

Next one is 59g

One without prop has a carbon strip on the underside - 60g without prop

Props can come off and a nose cone taped on - doesn't seem to make much difference but looks better...

I usually use a 200 m/a lipo

Wing is 31g but will cover in doculam

Various rx but using Radiomaster with Pascal Langer's s/ channel compound

Zeitgeist flies very well as motorised glider or slope soarer - seems to dampen out pitch variations quickly (not quite the case in the earlier video as not enough rudder trim made life a little harder
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Wayne_H
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Re: Zeitgeist - s/c and galloping ghost

Post by Wayne_H »

Nick M wrote: 30 Oct 2020, 19:55 2mm depron (with apologies) - laser cut

some edges dodgy... had to run it through twice
Thanks for sharing info on your build process Nick ;)

I've had good success with depron & find it great to work with. I avoid hotmelt glue because of the weight & temperatures we can reach in my part of the world - 45c ambient & >55c inside a parked vehicle - have had the glue soften, not good :o I use slow set foam safe CA or the chinese "goop in a tube" glue from HK. For trim or full colour I use 1" & 2" coloured tape also from HK - sticks well and wrinkles can be removed with a covering iron on low heat (doesn't distort the foam). I also seal all the edges/joins with the iron.

Any chance of some info on your laser cutting setup pls - laser power, head travel speed, controller, software, etc. TIA
Cheers,

Wayne
Once a Retrobate, always a Retrobate............ ;)
Nick M
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Joined: 19 Dec 2018, 20:39
Location: Camberwell london

Re: Zeitgeist - s/c and galloping ghost

Post by Nick M »

That's probably why you planes are lighter than mine!

I'm a teacher with access to a laser cutter - we use 2D design - https://www.techsoft.co.uk/Products/Software/2DDesignV2

Unfortunately can only use the program in the department - which given I'm a language teacher is less than ideal...

It needs a vector file - I made a bmp and imported it - and then converted it in 2D to a vector file - with not that much success

In the end I imported the bmp and just traced a vector line over the plan

If I had done that at the start I would have saved the a huge amount of time. Each attempt to vectorize the plan almost worked and so I kept at it - to no avail. I have taken that route in the past with plans that are just an outline - but OZ plan had all sorts of extra details / shaded ply etc

You are very welcome to the 2D file if that helps - but the 2D doesn't allow you to do anything useful except in 2D design

When I'm next in I'll just check that it can't be exported as a vector file - if so I'll send it

I cut depron at 100% speed and 20% power

Machine on its last legs but they are getting a new one
Spike S
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Joined: 16 Feb 2018, 14:59
Location: Salisbury UK

Re: Zeitgeist - s/c and galloping ghost

Post by Spike S »

Employed as Specialist Technician RESMAT (sounds grand but really "Woodwork Master's Assistant") I spent about 6 years in a post-retirement hobby job using a school laser cutter/engraver with Techsoft 2D. Lots of 'homers' allowed with the excuse of becoming/staying fluent with the equipment and software. So lots of Balsa got cut.
Test cut always needed but 100% speed and 20% power (maybe less) sounds similar to what I used for 1mm to 2mm Depron with a 30W laser.
"Vectorise" also found to be a timewasting problem for converting shaded drawings but the ability to import raw .jpg or .bmp files as a second layer lends itself to easy tracing once you are fluent with the basic tools. Must save often as that simple, but effective, CAD programme only allows deleting the single last action.

Techsoft 2D files can be exported as .dxf files that should be usable in most other CAD programmes.
You may also be able to "print" to a .pdf file.

"Machine on its last legs but they are getting a new one"
Suggest you make them a silly offer and take it home for yourself ! ;)
Spike S
(Tune for maximum smoke)
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Wayne_H
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Re: Zeitgeist - s/c and galloping ghost

Post by Wayne_H »

Thanks guys, much appreciated. One of my many ( :roll: ) bucket list items is a laser cutter and/or router, for which I've been slowly collecting the bits n pieces. Consequently, always interested in what people have found successful. :geek:
Cheers,

Wayne
Once a Retrobate, always a Retrobate............ ;)
Nick M
Posts: 92
Joined: 19 Dec 2018, 20:39
Location: Camberwell london

Re: Zeitgeist - s/c and galloping ghost

Post by Nick M »

Good thinking re 'sensible offer - but when I say the laser cutter is on it's last legs - it really is

The LCD panel is pretty poor - and only hardened users know from memory what the options are!

Biggest problem is that it keeps not being recognised by the USB port - you set it all up then file doesn't go across

Live in London so no space...

Bah humbug!

On the bright side great to know that files can be exported as something sensible - my knowledge is on a 'get something printed' level - you know!
Last edited by Nick M on 14 Nov 2020, 13:13, edited 1 time in total.
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