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It all began when I started to attach my engine mount. The project I
purchased (partially complete) had already been fitted with the "old style) engine
mount angles. As you can see here, there was some alignment problems.
After careful measurements, I determined that the original builder did nothing
wrong. The engine mount was built wrong. Go figure. A new engine mount was
in order, so I figured I might as well build the "new style". This
called for the removal of the old angles, and fitting new brackets. |
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I laid out and designed a new engine mount from the prescribed tubing.
I built a jig to hold all the parts in place while being welded. I spent a bunch
of time cutting and fitting the tubing together.
All went well at the welding shop.
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This image is mostly for orientation. Several of the following
photos were taken while the fuselage was on it's side like this, but it's hard to
tell. So I figured I'd show this shot to help with our understanding. A few mods
which are underway in this photo: The center spoke from the "roll bar" was
removed and the seat back was built thicker where the spoke attached, to make a more
comfortable hand hold while entering and exiting. The side sticks were moved
forward 3" and a bullseye level was installed on the passenger's arm rest, near
the seatback. |
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This bad photo shows the area prepped to receive the new aluminum angle.
Notice the half moon cut in the floor to allow for working. This cut will be
repaired later. |
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On my workbench (such as it is) I prepped the aluminum bracket for
bonding. This was accomplished by sanding it with the orbital sander you see in the
background, loaded with 80# sandpaper. This aluminum was an issue in
itself. I hunted all over the central valley for a source, and the least
amount I could buy was a quarter sheet. So I had 3 sets made and sold 2 of them to
other Dragonfly builders.
One thing to address if you are having them made for you is to have the shop bend
against the grain. |
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After the angle was sanded, I tapped up the inside to keep epoxy off
of it. I used some green masking tape. The plans call for somewhere around 7
layers of 10oz bid (cut on the bias) to form the pad in which the angle will be imbedded.
I laid up all 7 layers on wax paper on my bench before transferring the buildup to
the fuselage. The inside corner (formed by the firewall and the fuselage side) was
liberally filled with flox before clamping the angle to the layers of glass. |
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Here's the view from the bottom. There was a bunch of flipping the
fuselage around, making the clamping and other work a bit easier. |
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Here's the cured piece with the clamps and tape removed.
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I then sanded the angle and the surrounding area. Flox was added to
the edge shown, and one layer of 7oz bid as laid over the angle. All edges and
corners of the aluminum had been rounder over with a belt sander prior to attaching to the
fuselage. |
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After the 7oz was cured. it was lightly sanded and the area was
prepped for filling in the missing foam, at the half moon cut. |
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The cut was then patched with the same thickness of foam that the floor is
made from. |
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Here's the underside, showing the foam patches being glassed into
place. I glued the foam pieces in place with micro, prior to glassing. |
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After all the glassing was complete, I drilled the assembly for
through bolting to the longerons. The arrows show the counterbore for the bolt heads,
through the 1" foam, to be seated firmly against the wooden longeron. |
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The entire area was then primed. This shot also shows my sub-floor. With
the canard bolted in place, I covered the area (where your feet go) with duct tape,
and laid up several layers of 10oz. This produced a removable sub-floor,
which will support the rudder pedals.
This will allow me to have my pedals essentially mounted to the fuselage, making
the removal of the canard less of a hassle. Since I'm going hoop gear, I can
have my brakes installed and working before the canard is installed. |
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This bad photo shows the bolts with nuts installed on the underside. |
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The counterbored holes were then filled with flox, and the entire
firewall was glassed, wrapping the first few inches of the fuselage, covering
over the floxed holes. I then drilled the engine mount holes, and hung the HAPI
engine. |
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Here's another view of the engine installation. Notice the layout
lines drawn on the firewall. This engine has since been removed and sold, and I'll
be installing a Corvair engine in it's place.
The only lost work was the engine mount. But that's not so bad. I learned
how to build one anyway. |
