Tuesday, March 08, 2011

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.

Tuesday, February 08, 2011

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...

Sunday, January 16, 2011

Boot Cowl and Instrument Panel Final Install

After numerous fitup iterations (trim, retrim), the boot cowling was painted.  Here is the cowling in the paint booth before priming.

Here is the primed and painted cowl with fine line tape demarcating where the stripe will be located.


Here is masking in preparation of the gray stripe.


Here is the boot cowl painted and riveted to the fuselage.  Overall, pretty happy with the painting results.  Had some run issues on the bottom when it was hanging vertical.  Runs seem more prevalent on second pass.  Seems like 25% reducing of topcoat is optimum.  I applied high temp RTV silicone at the flange forward of the firewall to seal off engine fluid and fume leakage.



The instrument panel is fastened to the boot cowl through a dozen screws with rubber grommets to insulate instruments from vibration.


Sunday, January 02, 2011

Avionics and Electrical Wiring Completion and Startup

I can't believe I've finally got a fully functional avionics instrument panel.  I put the juice to the system recently and, instead of sparks flying, all of the components operated beautifully without a hitch.  The biggest surprise was that the combination VHF radio, stick mounted controls and microphone/headphone jacks worked flawlessly: voice-activated intercom, stick-mounted PTT, frequency flip-flop and streaming music from a jack I wired in to play Pandora through my Iphone.  Still need to verify transmission quality.  Lots of micro-soldering work from a complete novice.  The Dynon Skyview required a little configuration identifying the engine sensors and took a little research to get the Garmin 496 to talk to the Skyview, but all works great.  The synthetic vision PFD is awesome.  It is with great relief that this phase of the project is done.  There was no Rans guidance to follow, therefore, independent consultation with component vendors was required.  Following are a collection of install pics over last few months, first off the as-built functioning panel.


Here is the firewall, which shows a blue capacitor I installed to filter engine electrical noise and hence reduce radio noise.  Buss bars nearly full.


I really like the DB connectors, as the crimped pins result in a really solid connection on the wire and snap into the connectors firmly and stay put.  I have used them exclusively in constructing wiring harnesses and in places where quick disconnects are required like near the wing roots where the strobe/nav lights connect.


Front headphone jack and wiring from stick harnessed into DB9 connectors; soldering jacks.  





Music jack


ELT-function tested

Dynon remote compass installed in battery compartment for primary flight display on Skyview


Radio wiring diagram


Constructing radio wiring harness with shielded wire




Transponder wiring diagram


Constructing transponder wiring harness with pins, wire and crimper






Soft start module for ease of starting in cold weather and reduce of strain on Rotax

Thursday, October 21, 2010

Electrical Wiring

Been quite awhile since my last post.  I heard a rumor that the electrical part of the project can take the longest, and I'm a believer.  Seems like every operation requires a phone call, as this stuff is just so new.  I started with the battery and worked downstream from there to the starter solenoid.  The engine compartment is completely wired.  I've got the Dynon Skyview engine monitoring module installed and all of the engine sensors wired to the wiring harness provided.  I'm currently working on wiring the gps and transponder to the Dynon display.  Here are some pics of the mess of wiring...





Sunday, September 19, 2010

Rotax Carb Mechanical Synch

I adjusted each carb so that each has the same power setting at high and low throttle.  This is important because each carb independently operates 2 cylinders and, if not in synch, excessive vibration will occur.  Procedure:  Advance throttle levers to full, then back off so that you can insert a snug feeler gage into one, then adjust ferrule on the other throttle cable such that the same feeler gage is snug.  Next pull throttle all the way back to idle.  Ensure that at the idle stop, no gap exists between carbs.  If so, adjust idle screw so that they are the same with no gap. 

I've got them set and will go with these settings at start up.  If excessive idle, I will back off each idle screw same amount, e.g. 1/4 turn.  If vibration still occurs, there is a way to synch carbs pneumatically by hooking up pressure gage and making sure differential pressures in intake manifolds are the same.