Chapter 15 Firewall - cutting and fitting

A deviation from plans is to use Stainless Steel rather than Aluminum.   

Edit/update - drilling to fast will heat up and dull drill bits.  Go slow and apply pressure for better results.

Made a template from cardboard.   Cleared off one of my 4x8 workbenches, placed scrap board to put underneath while drilling.  Borrowed a set of knock outs from a neighbor to make clean hole cuts.  The electric shear cuts wider sheets well but didn't work very well for trimming edges.  An angle grinder with a cut off wheel works pretty well for trimming the edges, but have to be careful not to heat the metal up to much.  The shavings from this are like little razors.  

Stainless can be hard to work with.   The hole saw grabbed and tore the metal a little here.   This hole was just for the knock out bolt.  Fortunately, the knock out cut this part out.

The sheet is clamped in place.   The cardboard helps align the knock out.

A uni-bit seemed to drill holes pretty well without tearing.  A sharpie marked the stop depth on the bit.

Still needing a little trimming, but is lining up pretty well.

Holes not cut yet that are needed are for the EMS system's D37 and D25 cables, alternator wiring, SDS EI/EFI, AFR probe wires, cabin heat, throttle, fuel source and fuel bypass return.

Stainless Steel parts from Cozy Girrrls.  Not all holes are drilled.  

Saw this technique either on an EAA video or another metal builder's site.

Cleco clamps hold the paper to the pulley so the holes can be marked with a sharpie.   Small dots mark where the cotter pin holes need to be.

  Keep the drill bit cool (I used water) and take your time.  These little holes each took about 10 minutes.   Black carbide drills work.   The drill press doesn't go slow enough and heats the bit up.

The sections covering the spar were added and fastened using rivets.   Some of the holes needed to be elongated slightly and edges trimmed in a few spots.   I put electrical tape on the inside edge of the holes for the vent lines to try to protect the aluminum from scratches when putting the firewall on and taking it off.    There is still a protective plastic sheet on the stainless steel.   A few more holes need to be cut.   

Flight Testing

Links to FAA Flight Testing Advisories:
https://www.faa.gov/news/safety_briefing/2014/media/SE_Topic_11_2014.pdf
https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC%2090-89A.pdf
https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_90-116.pdf

EAA Webinar on the Flight Test Manual:
http://www.eaavideo.org/detail/videos/homebuilding/video/5993410710001/webinar--introducing-the-eaa-flight-test-manual

Here's a link to Kevin Walsh's "Experimental Aircraft Flight Test Protocol":

http://www.cozybuilders.org/docs/Cozy-MKIV_Flight_Test_Protocol.pdf

I'll need to do some editing for mine, but it is really thoughtful of others to share with the group.
I've been reading this and will plan on using the data recording of the Skyview system to help reduce work load.   Also think I may ensure the Auto Pilot is working earlier in the protocol to help reduce work load and improve the accuracy of the flight tests.

Adding some notes here that will be incorporated:

Fuel Injection /Electronic Injection - Dual ECU Switch

When running dual ECU boards, this toggle switch activates relays which switch operation of the injectors from one ECU board to the other. In normal operation, one board is always firing the top spark plugs, the other fires the bottom plugs. The ECU select switch only switches the injector connection over to the other board. If one ECU board fails, you’ll lose one set of plugs but the engine should continue to run.

The recommended ECU checking procedure is to start the check on the backup ECU. At idle, Switch the ECU selector switch from Backup to Primary. If the engine continues to run, both ECUs are working. Now you can switch coil power off on the #1 coil pack. Switch that one back on and then switch off #2 coil pack power. If the engine continues to run, both coil packs are working.

Be sure to check that both coil power switches are back on prior to takeoff.

Chapter 17 - Vance Atkinson's springboard and electric pitch trim systems

Updated 12/25/2019

Vance's canard is unique and shows a universal joint that isn't on the plans Cozy IV.   Rather than a manual rod, an actuator with feedback will be installed.  I don't think I'll need the component that mounts on the wheel well if the actuator has enough force.  It seems its purpose was to reduce the travel distance of the T-handle and to bias the trim so pulling the handled would provide up trim rather than down.  Update - several of us with Cozy IV's have had to add more layers to make this type of spring a bit stiffer in order to have adequate pitch down force at cruise speed.  Vance flew my plane and said that it handled well.  The pitch force was not to stiff.

Vance later updated to an electric trim system, but a downside was if there was run away trim, needed to be disconnected to allow full elevator travel.   He accomplished this with a quick disconnect pin through the Heim joint.  We tried different springs to allow full travel if there was run away trim, but Vance did not care for the resulting stiffer/softer forces.

Here's a link to a photo of the plans to make a Davenport spring