Left Wing Construction: Attach Flaps/Ailerons, Wing Tip Fit-up

I got the control surfaces attached to the left wing.



Here is a closeup of one of the hinge points.

Next, I needed to fit-up the wing tip assembly.  The wing tip inside edge overlaps the rivet centerline by 5/16" so need to have a way to transfer hole locations onto wing tip.  I drew 2" line segments from hole locations to transfer to wing tip when put on wing.

Here is the final trimmed wing tip with minimum edge distance maintained from aileron.

Here is a rib section riveted to the aft end of the wing tip.  The aft end of wing tip is set flush with aileron aft edge in aileron neutral position.

The aileron neutral position is established by placing the wing spars on a linear piece of wood with shims of similar thickness.  A shim is also place under the aileron aft edge.  This results in the bottom of wing spars and bottom of aileron aft edge all in same plane or neutral position.

Here you can see trailing edges of tip and aileron matchup in neutral position.

I located holes for the nav/strobe lights.  I will utilize a single bolt, nylock nut and larger washer to fasten to wing tip later.

Cowling Fit-up and Final Install

The fiberglass cowling consists of upper and lower pieces that need to be trimmed to fit. Both pieces need to be centered and set 1/2" behind the spinner dome backing plate.  I used scrap wood as spacers seen here.

First off, I needed to trim the aft edges of the upper and lower cowls to fit and match the boot cowl joggle.

I used a Dremel cutoff wheel for a lot of the trimming and drum sander for edge contouring.

Here the lower cowl is trimmed to match the boot cowl and spinner dome plate.  For the latter, I wanted a  smooth drag-free contour transition.

Here is the oil check/fill access door installed.  It is recessed into the cowl.

Once the cowl pieces are trimmed, everything is taped together and holes are drilled and clecoed where the 1/4 turn fasteners and receptacles will be located.  Note the smooth transition from spinner dome backing plate to upper cowl.

Both cowl pieces were PPG epoxy primed in the paint the booth.

Here are completed pics of the cowl assembly with Superflite urethane top coat paint and quarter turn fasteners installed. 

One modification I did was obtain a tubing bender and bend/realign aluminum carb. overflow drain tubes so that they would daylight through the bottom cowl opening, as opposed to drilling holes for their exit.  This way, lower cowl slips on and off with ease.

Aileron and Flaps Final Construction

Hardware was installed on the covered and painted flaps and ailerons.  Shown here is a flap and aileron with attached horns.

Next up is assembly of the aileron spade assembly.  This feature is used to reduce stick forces and create something similar to "power steering".

The aileron must be balanced in the static position, so a counterweight is fastened to the aileron spade.  I'm told the weight also dampens out oscillations in the aileron.  Two aileron hinge points are placed on the sharp edge of two pieces of horizontal angle iron.   Weight is added or subtracted until the aileron is parallel with the angle.

I obtained lead shot from a local gunsmith and used it as raw stock for forming the counterweight.  I wanted to over-cast material rather than the alternative.

This pic shows one of the balance points.

I melted down the shot and used Altoid cans as a form.  This was much more cost-effective then obtaining lead sheet or plate, which Rans suggested.

Here is my smelting setup in my paint booth.  Lead fumes were exhausted by fan and I wore a supplied-air mask.  Lead fumes are extremely toxic. 

Here are the two resulting lead ingots.  I spooned off a lot of impurities resulting in these 100% beauties.

Here is the first balance trial, which was way too heavy.

Realized after the fact that I casted them way too thick so used a block plane to mill off material.  After many iterations here is a perfectly balanced aileron.  When I got close to balancing, I filed and sanded each ingot with successively finer grits.  I then dimpled the bottom side with large drill bits to remove material and nail the balance point.

Final counterweight attached to spade.

Engine Oil Pre-Heater Install

Since I've learned that it's not advisable to start the Rotax engine at temps below 50 deg. F without preheat, I installed a Reiff oil heating system.  I'll plug in this unit the night before any cold morning flights.  The first heating element was epoxied to the bottom of the engine block.

The second heating element is formed into a large clamp which attaches to near the bottom of the oil storage bottle, seen below.

The thermostat is epoxied to the bottom of the oil bottle.  Barely viewable below.

The plug-in cord was routed up to the top of the engine for access through the oil access door.  The cord was also grounded to the engine block.

Prop Spinner Fit-Up

The propellor spinner dome and backing plate have been fabricated to permit the 3 Kiev propellor blades to fit.  First off, the backing plate needed new holes transfer drilled to match the hole pattern on a 1" thick spacer which mounts to the engine propellor flange.  

Here is the new bolt pattern, with one bolt present...

Here is a side-view.  From left to right: engine propellor flange, backing plate, ring insert (not shown) and propellor hub.  Note: bolts through flange are too long and hit the gear case; vendor has since supplied shorter ones.

Next, I temporarily mounted the propellor blades to construct a poster board cut-out template.  This will allow me to transfer a  cut-out onto the spinner dome. 

Here is a tool supplied with the prop which allows me to set the pitch of each blade.  I needed to get the blades pitched properly so the cut-outs in the spinner will be accurate.

So here is the first of three cut-outs to be made at each blade centerline.

I started with a Dremel cut-off wheel and then "snuck up" on the actual line with a Dremel sanding drum and then smoothed up the opening by hand with 400 grit sandpaper.

Multiple fits were required to match the the contour of the blade and leave a specified annular space around the blade.

Once the cut-outs were completed, I needed to drill holes for fasteners which attach the backing plate to the spinner dome.  In order to end up with a spinner that spins "true" and not wobble, the propellor was assembled horizontally, pitched and laid on a flat surface.  The spinner dome was then placed over it which resulted in the backing plate and dome resting on the same plane.  At this point holes were drilled.

Next, nut plates were installed at all of the hole locations.

The rivets were countersunk, so flush with the plate.

Now ready for paint...