Turnigy Spacewalker half scale 168" 4.3m electric

Hi Meme, excellent craftsmanship and quite inspirational.  I have a 1/3 scale spacewalker and that is big enough but 1/2 scale - you'll be needing a trailer!

Originally posted by Mustang Sally I would make a hub with a woodruf key and a plate. Something like this:

Thank you. That looks just the right sort of thing. I'll see if I can turn one up....the tricky part is the keyways!

Weight

I have weighed everything built so far, all the remianing wood to build the wing and fus and then all the motors, servos, esc's, batteries etc. Total weight 35kg.

However, this does not include the covering. I have calculated 8.5 yards of the 60" wide Diatex 1000. Does anyone have an idea of what weight this will add when doped and painted?

My initial target weight was between 30kg and 45kg (a wide range because I did not have any good idea of what it would be), so it looks like I am somewhere within this range.

Andy

Tail Group

I am making the tail-group removal for easy transport so the next few photos show how I am attaching everything. This plane has strut wires between the stab, fin and fus so I don't need to worry about anything 'waggling' around.
I have made the stab so it sits on the fus and is located by 2 dowels. You can also see a hole in the stab where the leading edge of the fin slots through. You can also see a slot at the rear of the fus where the trailing edge of the fin will slot in.....



To hold the fin in place (which in turn holds the stab in place) I have fitted a captive nut in the leading edge woodwork......


This nut is then used to pull the fin down onto a fixed cross-member, from under neath the finished fus. This photo shows the cross-member made up ready for fitting to the fus....


Today I have finished fitting the fin and then competed the upper part of the fus rear.
This photo shows the fin being slotted into place......



And this one shows it fully in place.....


The leading edge of the fin is slid in through a close fitting guide fixed in the fus to give it a solid vertical location. This photo shows this guide and at the bottom you can also see the fixed cross member through which the bolt is fitted to hold the fin in place.....


And here is the fus as it now stands.....


All 3.1m of it........

The Wing

Now to the wing. I have had quite some debate as to whether to make the wing 2 piece or 3 piece. A two piece wing would give 2 panels of 7 foot by 26" wide, and eliminate the need for the wing joining tubes. I think a 2 piece wing could be nearly 2 kg's lighter. However, fitting the wing would become rather arduous as the plane would likely have to be held upside down. So, 3 piece it is.

Todays task, to make the wing centre section joiner, that sets the dihedral angle. This joiner also take a huge loading, with a 5g loop putting some 150kg load through this! It is made of a box section with cyparis spars top and bottom and 2 sheets of ply either side. Here are the 4 sheets cut ready for assembly...

The pairs of ply are sheets are assembled thus....

i weighed the parts before and after cutting the holes and the result was nearly 30% off.
OK, now I have built the centre wing joiner...




And now I have started to build the wing centre section. This is about a metre wide and has wing tubes for the outer 2 panels to attach. Because I have used 2 wing tubes either side it is necessary to build the wing panels with the phenolic tube as complete lengths and then cut them later - if they do not end up completely paralell then they will not work!....


And at the front are the attachments that latch over a cross-spar built into the fus (and there will be wing bolts at the rear)...

Here is a closer view of the wing tube attachment, showing the reinforcing pieces next to the ribs....





Because of the 2 wing tubes I have now started to build the first part of the right-hand outer wing panel onto the protruding tubes from the centre section. I have put spacers in so I can cut the phenolic tubes later....



Now I have completed the basic structure of the wing centre section I have load tested it. I had aimed to measure the deflection for the load applied and hence be able to calculate the effective modulus and then be able to calculate its breaking load. However, with the method used to load it up I cannot measure deflection acurately enough as it appears to pretty much zero.

Load applied is 150kg at the wing centre rib, with the underneath supported across ribs 4 at either side....
This is the wood suppport underneath..



Here is the set-up on scales ready to load up..


And here it is with the first 60kg of weigths on, which was then followed by my 92kg standing on it


I chose 150kg as this 5 times the weight of the complete fuselage assembly in a 5g loop. Considering there is lot more structure around the centre as well (and the fact that we do not intend to pull 5g) then this looks fine.