Spacewalker half scale 168" electric

[Andy Boylett]

My apologies to anyone who thought some of the posts on this thread were out of hand. It was definately not my intention to offend anyone. From now on this build thread will concentrate on capturing the build and comments from those that wish to make them. There will not be any discussion regarding the inspection process or its requirements. With the agreement and help of our forum man (Dave) I am removing some previous discussions that distract from this build thread.

Thanks, Andy

[Andy Boylett]

Rudder control

This is a dry-run assembly of the rudder controls. Not all the bolts are added as they all have to be removed later for final assembly in the plane.

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The EMCOTEC device is a servo matching unit. The 2 rudder servos are controlled from 2 different recievers. One of them can be adjusted from the transmitter, the other is then adjusted using the EMCOTEC device that can adjust centre and end-points. It is set using the magnet attached to the ‘red flag’ in the photo.

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These are Turnigy HV servos in a HobbyKing rudder servo mounting system comes complete with the 5 inch arm).

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[Andy Boylett]

Stabiliser Fixings

After I calculated the real loads on the stabiliser – just 3.5kg each side it became apparant that the stabiliser wires don't carry much load. Also, I was already unhappy with the mounting system I had for the stabilaiser because when I assembled it I had to check it for square every time – the brace wires held it in place so any adjustment on them pulled it out of square. Every time I assembled it I found it out of square.

So, I have gone back to plan a) which was to bolt the stabiliser on, nice and rigid, then the bracing wires are just for show....or even better they are there as a back-up in case anything went wrong with the main fixings.

Here are the plywood mounting plates for the 2 bolts. This looking from under the stabiliser, inside the fuselage. Below is the stabiliser in place..

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And this is from above..

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I have tried putting a 3.5kg weight on the trailing edge of the stabiliser, on one side only, and the result looks good. There is some expected deflection of the spar, but not excessive. It is also unlikely to ever see this 100mph load on one side only as any possible high speed scenarios would apply the load to both sides and hence not even need the bolts!

I have also been modifying the mounting points for the bracing wires on the under side of the fus. A ss strap right through with no soldered joints will elimiante some possible failure points. I also realised that there should be 2 mounting points and nbto one! These straps would normally on a model be wrapped around the outside, but this would not look scale. I have therefore spent time with a milling bit machining a slot all the way through the fus so that the 2 straps can be made to look like their full size versions.

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The straps will be glued in place after covering and they are positively located by a screw in the middle of each they can be seen in th epictures).

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[Andy Boylett]

Covering Test

I have been having a go at covering using the Diatex 1000 nylon material I have. Some of the LMA members use glues and dope in a very diluted state - glue is 50/50 with thinners and dope also 50/50. Like this there has to be

- 2 costs of dope

- 2coats of glue

- 5 or 6 coats of dope to finish

So possibly 10 coats, with light sanding inbetween each. I also noted that the people doing this are trying to achieve a very smooth finish to replicate metal. I wnat to achieve a finish the same as on a full size plane using Diatex. Now, I ntoiced on the manufacturers site that they talk about using just 2 layers of ‘sealer’ diluted 90/10. I called them and they said their sealer was similar to dope.

Ah, ha. This is worth a try. It may also be that the reason people using the 50/50 mix have to be very careful not to get drips going through the fabric is because the surface tension of the dope is greatly reduced and it can easilly leak through. I decided it is worth a go with a less dilute process so set up a test piece…

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This is a 180mm square piece of very soft balsa – very soft so as to be as porous as possibe. It has had:

- 1 coat of 90/10 dope/thinner to seal the balsa

- 1 coat of glue 90/10 to stick the Diatex on

- Shrinking of the material with a hot iron

- 1 thin brushed coat of 90/10 dope in one direction

- one hour wait

- another 90/10 brushed dope at 90 degrees to the first.

The result looks good. The finish still looks just like the starting material, like it does on full size. There do not appear to be any holes. I can pour water on and nothing comes out the other side.

What do you all think? Am I trying to do it to quickyl? Should I do it with more thinner and more coats?

[Andy Boylett]

Finishing the Modifications

After the static show where I took this plane I decided to modify some parts to make it more transportable.

This is th ecompleted fron undercarriage mount, now fixed to th ewing and not the fus…and fully sheeted….

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I have also chnaged the trailing edges of the wing centre section from being sheeted, to being solid balsa….

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[david clarke]

Nice one Andy,i am so pleased your thread is back on it would be a shame not to see it through to the end.
By the way nice TX
Cheers,Dave.

[Andy Boylett]

Thanks Dave. The model had its first power trial all set up on your old tranny, which is why it was roaming around in the background there If my son Sam ever gets around to uploading the video I will put a link to it.

[Steve Rickett 2333]

"There do not appear to be any holes. I can pour water on and nothing comes out the other side."

Hi Andy,

I think your best bet to check if there are any holes in the surface is to spray a light coat of primer over the surface...It can be very annoying to think you got rid of all the pin holes only to paint the model and find it looks like a pin cushion!

When you come to paint the model, if you spray primer first, and find pin holes, these can be filled by brushing on a coat or two of primer over the affected area(s).

Cheers

Steve

[Andy Boylett]

Thanks Steve,
I'll have a go on that test piece tommorrow and see what it comes out like.

20 years ago I spray painted a mid engined car I scratch built, so I think I might be a little rusty at spraying! So, today me and Sam got the spray gun out and painted the whole of our shed and decking with a light brown stain!! A bit patchy to start with, but well worth doing

Cheers, Andy

[Dave Collis 2296]

Hmm! Never seen a brown Spacewalker. There's always a first time, I suppose

[Andy Boylett]

Yes Dave,
In theory the brown wood preservative would be good for the balsa but might not look too good

However, the jury is out though. Sam did the first coat on our patio decking and then last night my other son, 13 year old Tomson, did the second coat and he was pretty good

Cheers, Andy

[robbieskipton]

Really Impressed with the rudder servo tray...... .... Need to investigate these more

[Andy Boylett]

Really Impressed with the rudder servo tray...... .... Need to investigate these more

Hi Robbie,
All the rudder servo parts are here... http://www.hobbyking.com/hobbyking/store/uh_listCategoriesAndProducts.asp?idCategory=387

I bought mine when they were on offer at $35

However, have a look at the 4" ally arm at the top of that page.. http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=14849
This one is $4 I have bought some already
Cheers, Andy

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[Andy Boylett]

After doing the first few runs of the motor I had 24 batteries to charge. This prompted me to get our chargers set up in a very useable way.
Because I am disabled I use a trailer for my models and equipment when I go flying. One side of the trailer contains my 6 battery charges, all connected to two 12v 100amp.hr liesure batteries. What I needed was a way of moving the charges and equipment to where I am charging when not using the trailer. Here is the result below.......

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Each box contains 2 chargers and has a space for a big LiPo firesafe charging bag. Also, all the required leads are permanantly attached with long balance extensions so the batteries can easilly sit in the firesafe bag. You can see a 13amp plug in there. This is to plug into the 12v power supply. In the 13amp plug I attach the plus wire to the earth and the minus to the nuetral - thus eliminating the 13amp fuse and also preventing an accidental connection to 240v. The 12v liesure batteries I use have 13amp extension plugs attached to them. Here are the 3......

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[stewart clifford]

"now where did that bloomin cat go?" He must be in one of those boxes.

[Rob Buckley]

You'd have thought somebody would have noticed, really!

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[Andy Boylett]

nice one Rob

Here is Murphy, sat in the caravan !!

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[Aaron norman]

Looking good I have been watching this build and have to say you are very good at it keep up the good work can't wait to see it I'n the air . Btw is that cat lipo powered lol

[Sam Boylett]

Looking good I have been watching this build and have to say you are very good at it keep up the good work can't wait to see it I'n the air . Btw is that cat lipo powered lol

Much better than putting a noisy petrol engine in it

[Andy Boylett]

Looking good I have been watching this build and have to say you are very good at it keep up the good work can't wait to see it I'n the air . Btw is that cat lipo powered lol

Much better than putting a noisy petrol engine in it

There would be no problem getting that engine purring nicely then !!

Welcome to the forum Sam. You do realise you will be flying this.

Maybe you could recalculate the engine power. Instead of 20hp (horse power) it is probably 40,000cp (cat power) or 40Kcp (killo cat power)