Jim.Thompson's blog View Details
Archive for December, 2011
Posted by Jim.Thompson | Dec 10, 2011 @ 09:53 PM | 7,171 Views
The wipers are formed with the mylar tucked under the wing skin. Curing as I write. All surfaces are bottom hinged.
Posted by Jim.Thompson | Dec 10, 2011 @ 05:46 PM | 5,741 Views
The wipers are being made using Joe Manor's description on his thread.
I have hung the plane like shown in the picture to ensure the "Q" cells splooge slumps onto the mylar to form the wiper surface but not onto the hinge line.
When the epoxy starts to kick and become jelly like consistency, I will slide the mylar strips under the wing top skin to form the required curve.
Posted by Jim.Thompson | Dec 09, 2011 @ 03:09 PM | 5,256 Views
I have glued in pine servo mounting blocks front and back of the servo position. These also bridge the top and bottom skins, so provide a bit of support for them in a vulnerable area.
The servos will be slid in between these blocks and then hot glued to the blocks. For subsequent removal if necessary, a piece of wire is heated and used to melt the hot glue.
I just need to monitor just how soft the hot glue becomes in when the plane is in the hot summer sun!
This is another reason for painting composite planes light colours. Apart from the HTD (high temperature distortion) concern.

Posted by Jim.Thompson | Dec 08, 2011 @ 06:28 AM | 5,415 Views
I cut a template for the control surface cut outs. This is to minimise mistakes and ensure both wings are cut the same!
Posted by Jim.Thompson | Dec 07, 2011 @ 06:35 PM | 5,196 Views
I fitted the wing/joiner/pin set to a previous fuselage. I used an aluminium root rib as a template to locate and cut the holes in the fuse. It all fits well, especially considering this was "reversed engineered". The original plug and mould was not meant to be for a moulded, two part wing aeroplane.
It started life as the simplest fuselage shape I could imagine to learn how to do fuse moulding with and inflation bladder. It progressed to included fin and fillets. And finally, this moulded version. So the alignment had to be done after the fact, which is not to be recommended for obvious reasons.

Posted by Jim.Thompson | Dec 06, 2011 @ 11:29 PM | 5,155 Views
These are the wings trimmed and fitted together with the joiner and pin. Alignment is correct! I will now make a root alignment rib out of 2 mm aluminium to act as set out guide for cutting the holes in the fuselage. Then I can do a full test assembly!
Posted by Jim.Thompson | Dec 06, 2011 @ 03:50 PM | 4,973 Views
I pulled both wings from the moulds this morning, and they are successful! There is a slight blemish on one in the form of small bubbles too small to show up in the pictures. It will be quite repairable and is only about 10mm or so diameter. I am suspecting that it is my old blue foam offgassing come back to haunt me again! I had many vac bagged wings form bubbles when heated either in the hot box or in the sun when using this same foam. These moulded wings have foam cores aft of the spar.
And the only thing that I had forgotten to install were the servo cover spacers in the top skins! Not a major problem, but will have to be done on the next ones.
The weights are 425gram and 440 grams untrimmed. The joiner will be around 70 grams trimmed. No lightweight, but I was very generous with the resin. No sign of any resin voids!
I will type up a list of process and build sequence, get it laminated and pin it on the wall of my shed before doing any more. Especially for moulded jobs. I often manage to forget some small (or large!) aspect of the job.

But I am really pleased, quite excited actually!


Posted by Jim.Thompson | Dec 05, 2011 @ 05:22 PM | 4,863 Views
The wings are glued and closed up in the moulds and in the hot box!

Is there anyone reading this blog?

Posted by Jim.Thompson | Dec 05, 2011 @ 03:58 AM | 4,790 Views
I have closure!
The first wing has been glued up and closed! The picture shows the servo wires in place and some small wooden blocks to act as cheek blocks to mount the servos.
I will glue up the second one tomorrow.

Posted by Jim.Thompson | Dec 04, 2011 @ 02:48 PM | 4,848 Views
The Drag spars are being glued into the bottom skins along with the control surface LE spars.
The drag spars were pre made by winding 30mm wide strips of 100gsm glass on plastic covered carbon rod for a mandrel. Then wrapped with more plastic and allowed to cure. The spiral wound plastic pulled out of the cured tube easily.
The LE spar was made using the drinking straw method. The straws were threaded onto a mandrel and taped together. Then they were spiral wound with glass as above. Wet out, slipped off the mandrel and cut to length before gluing into the lower skins.
Drop sheet plastic was placed on top and the top skins and moulds where then clamped onto them for curing.

Posted by Jim.Thompson | Dec 04, 2011 @ 01:30 AM | 4,661 Views
The main spar has been glued into the lower skins and sanded to clearance fit under the top skin.
I'm now working on the drag spar and the LE of the control surface spar.
I have made up some 7mm dia glass tube which I will use for the drag spar. That is ready to glue into a dremelled trench. Why the trench? Because I mistakenly continued the foam core right past the hinge line etc. in my relative inexperience! I'll leave and appropriate space next wing.
The LE surface spar will be formed on drinking straws, glued in while still green and some drop sheet plastic placed over them before closing the moulds overnight for them to cure into correct depth. If I was more experienced and confident, I could do them last before gluing and closing the wing skins, but I want to see just how much they compact out of round on the first wings.

I've also created joining "lands" or shelves at the LE and tips. I used two rows of 50k tow and formed them up by clamping a waxed strip along the mould flange and pushing the tow into the LE. This will give me good surfaces to glue together.