A short update on what’s been going on

Windscreen

Windscreen 

A lot of thought and permutations have gone into the design of the windscreen frame.  Design was starting to get out of control with too many complicated curves, eventually I had to get a grip of myself and simplify it 😂

I have decided to use a combination of 18mm plywood and red pine. Mainly because that’s the materials I have at hand. As you all know by now, to build one of these is bloody expensive 😂 so you need to use what you’ve got.

I am going to bend a length of 20mm tube and attach this to the back side of the plywood hoop, it will also be attached to the side panels all the way down to the deck.

After a lot of time on youtube researching what to use for the screen I have settled on 3mm Acrylic. I’ve hade a bit of practice with the heat gun and the drilling machine and believe I can do this without too much fuss 😉

The way I’ve designed the screen,  I think the curves are quite slow so I’m not expecting too much stress on the Acrylic sheet.

I’m going to go for a fully enclosed cockpit.

Carving the propeller

Uh 18 propeller 

Building the prop for my uh 18. 

I was lucky enough to be able to borrow the prop from team hover members Chris and Ollie’s hoverwing ( their craft is almost ready) timing was good and I got a loan of it for a couple of weeks to take some measurements from and carve my own 😊

Firstly I made a router copier, using a frame I had from an old treadmill. I have to say, with all the cutting and grinding discs I used it wasn’t worth the bother using second hand material, I’d have been better off buying new steel and starting from scratch.

Anyway I made up the copier and it works a treat 😊 I set about trying to find a suitable lump of wood to practice on, timber merchants round these parts are not helpful, they don’t seem to able to think beyond stock levels on their computers 😂 I purchased a sleeper to practice on - wrong 😳 this was green timber, treated and soaking wet, not good.

Eventually I was able to purchase some suitable planks, I laminated them using epoxy resin and made up some clamps from 10mm screwed rod and 40x 20 box section. Again, like the copier, this worked a treat. 

I waited two days before nervously removing the clamps ... success! - everything held nicely.

Next job was to make the jig to take the template prop and the blank.

My first attempt at carving the prop wasn’t good and had to chuck that one away. I realised that I needed to take measurements from  the original prop and mark out grid references on the blank, then to make some saw cuts along the lines I had drawn for reference. 

A hammer and chisel was then used to rough out the basic shape, then to finish it off with the carver copier. I have to say I was fairly chuffed with the result.

Next I used a belt sander, an orbital sander, a sanding block and a fair amount of patience 😂

Finally a spray with some guide coat and a last rub down with the machine and the prop is done. All it needs now is to be glassed and balanced.

Thrust duct continued

The thrust duct continued

With the underside of the hull complete and the skirt on, the hover has been lifted off the trestles and is now sitting in pride of place in the centre of the workshop floor.

At last the thrust duct is in place 😊 I hooked the duct up to the hoist, manoeuvred it into position and spent a lot of time making sure it was level in every direction, and I mean a lot of time 😂 I had to get this right. It’s beginning to look like a hovercraft now and not an ironing board 😂

It took me a little time to work out where the flat spot was to be cut, then the penny dropped (clang) 😂😂

So that’s it glued and set in place, it still needs to be glassed to the hull.

It’s November here in Scotland and there’s a hard frost, I have five electric heaters in the workshop and can only get the temperature up to 12 degrees c today, so definitely no glueing happening anytime soon.

Uh 18 hoverwing skirt

The skirt

I’ve been making up the hover skirt, once you get into it, it’s not so complicated. I found the trickiest bit was to get it to hang right. So I’ll tell you how I have done mine.

When I first put mine on it was terrible, sagging in places and too tight in others. 

So what I did was sit the hover on trestles so it’s a good couple of feet off the ground, then start at the back of the craft by marking the centre of the skirt fabric top and bottom, use these marks to line up with the centre line on the hull top side and underside to help get it hanging right, connect up the inner and outer rear and the rear corners.

Next use drawing pins and pin the outer skirt to the outer attachment full length rear to front.

Next crawl underneath and start pinning it up on the inner attachment, working from the rear to the front. That way you can keep an eye on the bag remaining even all the way to the front - it should resemble a U shape. However as you approach the front of the craft about a foot or so before the lift duct, the skirt will begin to bunch up in places, apparently this is ok, you just add in an extra screw where needed. Just make sure you maintain an even U shape the whole way.  been making up the hover skirt, once you get into it, it’s not so complicated. I found the trickiest bit was to get it to hang right. So I’ll tell you how I have done mine.

When I first put mine on it was terrible, sagging in places and too tight in others. 

So what I did was sit the hover on trestles so it’s a good couple of feet off the ground, then start at the back of the craft by marking the centre of the skirt fabric top and bottom, use these marks to line up with the centre line on the hull top side and underside to help get it hanging right, connect up the inner and outer rear and the rear corners.

Next use drawing pins and pin the outer skirt to the outer attachment full length rear to front.

Next crawl underneath and start pinning it up on the inner attachment, working from the rear to the front. That way you can keep an eye on the bag remaining even all the way to the front - it should resemble a U shape. However as you approach the front of the craft about a foot or so before the lift duct, the skirt will begin to bunch up in places, apparently this is ok, you just add in an extra screw where needed. Just make sure you maintain an even U shape the whole way. 

Dynamite daisy preparing the vynil for glue

Uh18 hull vacuum bagging

The hull

We have finally reached the stage of building the hull.

I have built a table the same size as the Hoverwing to build it on so it is at a good working height. Experience over the years has taught me to make things simple and comfortable to work on; it makes life so much easier.

The foam sheets were laid out on the table and marked out according to the drawings, however I have opted to take 3 inches / 75mm off each side thus reducing the width of the craft by 6 inches. There are three reasons for doing this , the first is because the door width of my workshop is 8ft and this would make it difficult to get the craft out through the door. The second reason is there’s no need to build such a big trailer, the third  reason is because I can.

After marking out the foam sheets I then made up stringer guides for marking out the shape of the hull. This worked out perfectly, I then drew round the stringers with a marker pen giving me lines to work to when it came to glueing the foam together. 

I have opted for using the epoxy method and vacuum bagging, I note that other builders have on occasion gone for gorilla glue and have found it to be a powerful expanding glue that is perhaps wrong for this stage of the build and ended up having to use many heavy weights to hold it down. As it turns out vacuum bagging isn’t that difficult to do.

We made up a vacuum pump using an old vacuum pump from a refrigerator. First thing to do is identify that the pump actually works, then step two is to identify which pipe sucks in as that’s the one you want. We added in a distributor vacuum from an old MG car, these vacuums can be found very cheaply, and a micro switch so we were able to calibrate the pump to switch off at 144lbs. We also added in a one way check valve so that the bag would maintain the pressure until the pump kicked in again.

We did this by making up a trial bag for practice. 

4 screws in each top sheet to stop them from moving inside the bag during the vacuum process, polythene sheet down and blankets to cover the vacuum  pipe, bag sealed with duct tape, pump on and the job’s a good one.

Trimwing and stabiliser

Trim wing stabiliser 

We decided to go off plan with the trim wing and stabiliser, having previously built one following the Uh plan for another craft we found that whenever we handled the foam it would get bruised easily and leave dimples, which needed a lot of work to repair them. So by going off plan and building a wing that is more like an aircraft wing it would be lighter and stronger.

Thanks to Team hover members Chris and Oliver for doing the design.

I have built another bench 8ftx3ft in the workshop for this job

I had templates for the ribs laser cut in aluminium to help me get as an exact size and measurement as possible.

Once the ribs had been cut out with the hot wire cutter , they were set out on the bench.

I have made my wing 7ft long and not 8ft as stated on the Uh drawing , the reason for this is because the doors on my workshop are 8ft wide therefore I would not be able to get an 8ft wing through an 8ft door 😂

I don’t think this will make much difference to the handling of the craft.

I dragged the duct over to the bench and centred it with the centre rib on the bench, this method helped me to confirm that I had the boom ribs/ stabilisers in the correct place.

Although this would seem to be a lot of work and effort I think it will be worth it.

https://youtu.be/usiRmftapLkhttps://youtu.be/PBeCSVKFwVshttps://youtu.be/HDAyu5voP2Qhttps://youtu.be/