UH-13P Construction Log - Page 15

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 Sun April 10, 2005

 Second coat of light weight drywall spackle.  The seat still fits after the epoxy and fiberglassing!  I rounded the edges of the top of the foam at the sides in preparation for fiberglassing.

The seat is much stronger now and I think it should be able to support me and a passenger without breaking.

The lift duct was fairly hard to shape and I pretty much just eyeballed it.  The front of my duct is higher than on the normal 13P.  I am hoping this will help it eat water a little less.  I will sand out the spackle and then fiberglass it with strips of 6oz cloth.  Then I will put a layer of 6oz cloth on the top of the foam.  I'll use bondo if needed to smooth things out. 

Installed seven hard points for the lift duct safety grate.  I used 1" hardwood dowels and fixed them in the holes with a thin mix of epoxy and microballoons.

Tue Apr 12, 2005 

The first picture shows the fillets I put on the bottom of the seat to help strengthen it.  The top was covered with 6oz fiberglass.  It is really solid now.

The rest of the pictures show the duct after some more light weight spackle and sanding.  its just about  ready for fiberglassing.

Fri Apr 14, 2005

 I fiberglassed the top of the craft with 6oz fiberglass.  I used strips around the inlet radius .  The front has two layers on top of the triangle and about 4 layers right at the front around the nose.  I wrapped the cloth under the dash overhang.  I will need to coat it with a layer of epoxy and micro balloons.  I'll smooth the top out with either epoxy and micro balloons or some light weight bondo.  I don't know which is easier to work with.  The duct tape along the sides and inside of the duct is so I can cut clean lines and remove the excess cloth once the epoxy starts to setup.

Sat Apr 16, 2005

 Can you believe I spent the whole day putting this little bend in the rear idlers!  I had to go buy some roll pins.  Of course I couldn't find them individually but instead had to buy a 330 pin assortment for $20.  Oh well they worked perfectly.  I probably could have put a little more bend in it... But the belt alignment is close enough...much better anyhow than the bar without the bend.  I can probably bend this bar a little more.  I followed Marquis directions and welded a piece of 1" 1/8" angle iron on the 5/8" nut.  Then I used the drill press and copious amounts of drill lube to drill the hole for the roll pin.  The roll pin holds the nuts so they can't turn the idler bar.  Without the nuts secured in place the idler bar will turn once you start to tension the belt.

Sun Apr 17, 2005

 I painted the EMT control rods black.  I think the control stick looks good now all black.

I have 1 trim wing and 3 rudders.  I sanded the rudders smooth in preparation for fiberglassing.

I fiberglassed the thrust prop with 6oz fiberglass cloth.  When the epoxy starts to harden I take a razor knife and trim off the excess cloth and epoxy.

Wed Apr 20, 2005

 I started the  trim wing today.  I used an aluminum ruler clamped top and bottom of the wing at about 3" back from the leading edge to guide my hand held hot wire cutter.  I cut a 1"x3/4" piece of pine to fit between the trim wing mounts.  I am using 1"x1.5"x1.5" uhmw plastic and 1/4" stainless steel screws 3" with the heads cut off.  I drilled holes with my drill press in the uhmw and then used a jig to drill the holes in the trim wing spar ends.  The jig was a piece of 1" 1/8" steel tube with 1/4" holes drilled in it.  I clamped it to my table saw then used a square to line up the wood spar to it.  The uhmw blocks are going to be screwed to the end of the trim wing supports.  I epoxied the screw posts into the spar and held it in place.  You can see it in the picture with my tool boxes.

 

Thu Apr 21, 2005

 I used 5 minute epoxy and duct tape to join the leading and trailing edge pieces of the trim wing to the 3/4"x1" spar.  I cut the leading edge 3/4" shorter to leave room for the control arm.  The uhmw bearings and stainless steel 1/4" pivot points work great and are as smooth as silk.

Fri Apr 22, 2005

 I made the top rudder mounts out of uhmw and aluminum angle.  The uhmw is 3" x3/4"x3/4".  The aluminum angle is cut at 3/4" .  A 1/4" stainless bolt holds the angles to the uhmw. These 3 supports are screwed into the underside of the trim wing spar.

I used 3" deck screws to hold the trim wing uhmw mounts to the ends of the rudder trim wing arms.  Screws were countersunk and predrilled.

The last picture shows how I am thinking of building the mount for the rudder bottoms.  I will add the two additional arms to either side of the craft.

Sat Apr 23, 2005

 I started early this morning around 8am...Its now 3pm.  I have put the spars in all the rudders and drilled the holes for the 1/4" stainless steel pivots. I attached the top rudder mounts to the bottom of the trim wing.  I made the arms for the rudders and epoxied them into place.  I still need to cut the top of the rudders at an angle from the pivot point to the leading edge to allow the trim wing to go down more and not interfere with the rudders.  I am going to use an aluminum ruler to attach the rudders at the pivot points.  I got the idea from Dave builder of the Oblio among other hovers.  I am starting to get excited.  The rudders and the trim wing are the last major piece of the puzzle for fabrication.  The rest is cake.  At least I hope...

I cut the rudders at an angle to allow for more down elevator.  Probably way more than I need but better to be safe...

I am not having much luck with the controls... 

Sun Apr 24, 2005

 Drilled the bottom mount holes for the rudders.  I used 10-24 2" bolts.  I counter sunk the heads into the uhmw blocks.  I used an aluminum ruler for the pivot bar.  The rudders are exactly 40cm (15 3/4") apart.

Tue Apr 26, 2005

 I skinned the rudders and trim wing with a light coat of light weight spackle to fill all the imperfections

I cut the bottom rudder support down to its final size and used the trim router with a 3/8" round off bit to round off the edges.  Basically just did it to take the sharp edge off it.

Fri Apr 29, 2005

 I fiberglassed the trim wing with 1 layer of 6oz and a layer of 4oz tight weave over top of that.  I layed the two layers of glass on at the same time and used one single piece of 6oz and 4oz so there are no seams.  Actually I layed the 6oz on first then got the wrinkles bubbles out with the roller and then I put on the 4oz and did it again.   It was a pain laying the glass and getting out all the wrinkles/bubbles at first.  I just kept working it and eventually got them all out.  1 down 3 to go...

The last two pictures are just a couple of head shots with the fan in the duct.

Sat Apr 30, 2005

 The rudders and trim wing are fiberglassed.  I used a 6" wide 6oz piece of glass on the leading edge of the rudders then I used one piece of 4 ounce glass to cover the entire rudder. 

Sun May 1, 2005

 I trimmed the excess glass off around the edges of the rudders.  I used a light weight spackle on the edges to smooth out the foam.  I will coat with epoxy later.  I used the spackle on the trailing edge too.  I will coat it with some epoxy to harden it up.  

Thu May 5, 2005

 I have been working on the hovercraft the last few evenings. 

1st and 2nd Pictures -I used thin pieces of uhmw 1" rod to act as washers on the inside and outside of the control stick where it mounts to the under seat control rod.  This removes the metal on metal contact and smoothes out the stick.

3rd Picture - I used a stainless steel eye bolt at the end of the control stick to attach the trim wing cable to.

4th and 5th Pictures -  I used an old socket that I drilled out and cut short to act as a spacer to hold the fender washer so it wouldn't rattle.  It should also act as a solid slippery surface for the cables to ride on.

6th picture - The underside of the seat.

7th picture - I am going to end up using these pulleys I originally got from UH for my controls.  They are smooth and there is no gap between the pulley wheel and the case for the cable to get stuck in.  I am going to mount them level with where the cables attach to the control bar under the seat.

8th and 9th Pictures - I didn't like the angle aluminum control ends for the rudders that I fabricated earlier.  There was no way to prevent vertical play.  I picked up some 3/16" aluminum and fabricated these triangular shaped control ends. I will screw them to the bottom of the rudder pivot arms.  I am planning on cutting 1/4" slots in them to allow for the pivot point to be adjusted/fine tuned so I can dial in the right amount of rudder movement.

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Any Questions?  email brendin@hovercrafters.com