Saturday, December 9, 2017

Chapter 25 Finishing - Wings & Canard

I've been doing finishing work interspersed with other tasks.   My short term goal is to get the epoxy wipe done to protect the surfaces.  Then before priming, sand with 220.  I'm using West Systems and read several of their instruction manuals several times. I think a there's a few paint jobs that didn't last very well because bad advise was given.  West states that the last sanded epoxy coat over the filler makes an excellent substrate for polyurethane paint.   Logically, the sooner the surface can be made smooth, the better.   Primer is heavier than filler.  A smooth glass surface takes less filler.
I tried to do most of the sanding outside, but occasionally the wind would cause the air to flow out the large doors.  Applying the epoxy at night outside tends to draw bugs, so having the lights up high and working indoors reduces contamination.


Sanding outside at night has a benefit of making it easy to find the low spots by shining a shop light down the surface.   It also reduces the huge mess the dust makes.   The granularity of the dust from 36 grit isn't bad, but 80 and 120 grit starts to make really fine powdered sugar type dust.  Fans placed off to the side help keep the bugs and dust from being a nuisance. 
I applied a "cream coat" to sand off before doing the epoxy wipe.  Most of this gets sanded off but since it is epoxy rich, helps fill in any pin holes, drag marks and low spots.  Where the light is shining off the surface, you can see a smudge from my finger wiping on the surface.   This indicates amine blush.   If left on, it tends to load up the sandpaper, can cause problems with epoxy curing if applied over it and also cause yellowing.  It cleans off with a little soapy water.

Two padded saw horses, an output table and a shop light stand with a pad helped position the wing so the bottom could be sanded on without any rocking.
One of my Paulk work benches with 3/4" pegs works nice to hold the canard on the trailing edge so the leading edge can be worked on easily.   The shop light shining down the surface reveals some low spots that are probably only .004".   I'll do another fill/sand.
I watched a bunch of Eastwood videos on prepping and painting and decided to clean the dust and debris off with a mix of water and alcohol and let it dry.  Without doing this, when micro or epoxy is applied over a more dusty surface, the dust thickens up the micro as it is squeegeed and the excess is reapplied to bare areas.

Chapter 21 Strakes - Fuel caps

These are not the plans Usher fuel caps.  Several folks recommended the Newton caps because they don't leak and you can use just your fingers to remove them for fueling.  Locking versions are available.  The two hole saws (2 1/4 and 2 1/2) worked well.   Cut the 2 1/4 hole through the top layer first but not through the inside skin.   Then make a cut with the 2 1/2 hole saw just through the top skin and then clean the foam and micro off the glass where the flox needs to bond.  In retrospect, installing these caps before glassing the top skins on is probably better.   You can more easily decide where you want the caps to be.   Also you'll have less debris in your tanks.  I'm not sure how well the caps would hold pressure for the leak test.   
Don't try to clean the debris out with a vacuum.   The air rushing into the opening will scatter particles everywhere in the tank.   Vance recommended this duct tape trick.  I also used some wet paper towels to mop up the junk that fell in.  A long skinny dowel worked good for dabbing with duct tape and "mopping" with the damp paper towels. 


Flox filled in the gap between the skins for a glass to glass bond.  Then the neck was cleaned with alcohol and then buttered.   A short piece of pop sickle stick with electrical tape just long enough to catch the inside flange was wired to the longer stick.   The neck was buttered with flox and gently allowed to settle down through the flox.  The extra that squeezed through dropped onto a paper towel inside the tank.   Visible flox that was dripping was carefully extracted before it hardened.   The neck needs to be oriented properly.   The top surface of the cap will slightly higher than the strake surface when they're installed.

Saturday, November 25, 2017

Chapter 23 Engine Installation - prop, extension, cowl

Catto 68" diameter 78" pitch prop with nickel leading edges and erosion tape.  

Freeflight Composites cowl.   Did multiple test fits and the line that was marked looked like it was going to be pretty close so I trimmed outside of that line.   To match the plans, the cowl needs a lip along the front edge, so I trimmed off where the CF meets the lip at the turtle back and similarly, trimmed the bottom cowl.    Then used hot glue and pop sickle sticks to hold the trimmed section on as a form for the inside lip.

The blocks had to be moved in order to apply the BID that lays up in front of the cosmetic piece.  This particular area of the cowl lips were a little proud and met the wrath of the belt sander.
Pop sickle sticks and hot glue worked pretty well and was easier to remove than Bondo.
To install the Camlocs, drill 1/2" hole where the cleco holes are.   Then drill 1/8" holes for the rivets to hold the receptacle.   The bottom hole here has a Camloc receptacle riveted in.   I used a small drill bit to bevel the holes for the rivets so the heads are flush.  I made a simple jig to locate and drill the holes for the receptacles.
3 BID curing while the trailing edge is shimmed up to help correct a tendency to sag.
A layer of duct tape is on the bottom of the turtle back/spar lip.  Flox was applied and peel ply over that.  Nut plates were installed on the cowl and screws are holding the cowl in place for the flox to harden.   While the flox is still green, it's sliced with a box cutter along the seam.  Then after the flox cures a little more, the screws are removed and light pops with my hand broke the flox loose along the cut seam.


Chapter 23 Engine Installation - Aero Sport Power Build School - Superior XP-382 Wildcat

Parts painted and neatly laid out.  A 360 is on a cart in the queue behind mine.  Contact points were masked off and left unpainted where the case bolts tighten.  Heads are ported and polished.   I kind of wish I'd had the heads finished like the ones behind with black barrels and unpainted heads.

When I saw this I initially gasped, but you'll notice those are soft aluminum jaws in the vice and did not mark up the crank.  A plastic bag was put over the flange, greased up and then we heated the seal and slipped it over the flange and it popped right on.  This is a counter balanced crank.  The weights only go in one way.  

We installed the rod bearings.

The case accommodates roller lifters.  Also, the holes where the through bolts pass are machined to accommodate O-rings.   The case is also machined for the longer stroke.

Holes are drilled to accommodate oil flow back into the sump for inverted flight.  Nice to have if I swap the engine to something else some day.
The two additional drill holes are visible.


  Nozzles aka "squirters" will be installed that sprays oil into the bottom of the piston.

The crank, bearings, seals, silk thread, cam, roller lifters were installed.  Then some cardboard inserts held the upright rods in place when the other case half was put in place.    There are bolts installed and wired that keep the rollers in place.

The push rods are checked for straightness.

Sump and oil pump is installed.  Push rods, tubes, rockers are installed and valve lash is checked.  Only one push rod was one step to long (valve lash was under minimum clearance).   The shop has plenty of push rods in stock of various lengths.

Hall effect sensors installed.  Accessory case, oil pump, sump, coil mounts, various oil galley plugs and fittings are installed.  Install the alternator bracket before installing the Hall effect mount.

The SDS dual fuel pump assembly.


Ready to go onto the test stand after installing the injectors, fuel block, pipes.  The coils were strapped to the engine mount to avoid damage and make it easier to spot leaks.  They used their oil adapter instead of my 90 degree adapter.  The SDS system has a cold temp sensor in one of the cylinder intake ports.

"That's a lot of wires" was a common comment from the mechanics familiar with the traditional mags and Bendix systems.  It took a bit longer to connect everything but next time will go faster since they'll re-use some of the SDS harness.  Fuel pressure regulator was set to 40 .lbs with engine not running.   Post shut down has fewer steps than a bendix/mag system.  Don't have to re-check the mag timing, balance nozzles.

After getting the master ECU selected and electronic mixture set it started fine.  Pulp mill stack is in the background.

Test panel gauges.   The control box for my SDS system is setting on top of the panel.

Initially, WOT was around 2750 and after running for awhile consistently came up to 2800 RPM.  About 50-100 more RPM than the 200 HP engines with the same prop.

Temporary mount for the ECU.  A fuel pump is below it.
Cranked up after tweaking the electronic mixture knob a little richer.


Engine running at 2800 RPM and bypass fuel is visible going back into the fuel tank.  Fuel pressure was set to 40 .lbs without the engine running.  

Thursday, September 28, 2017

Chapter 23 Engine Installation - Aerosport Power built Superior XP-382

The engine should be here in December 2017 after the 3 day build school in Kamloops.

Wildcat XP-382

minus mags (10 lbs.)
minus mechanical fuel pump
minus carb or mechanical fuel injection


+electronic dual ignition (SDS)
+electronic fuel injection (SDS)
+pad mount & belt driven Planepower alternators
+cold air sump
+roller cam


Superior Millennium Steel Cylinders, SDS Electronic Fuel Injection and High Energy Ignition System with Dual ECU, Harness, Spark Plugs, Plane Power 60 Amp and 30 Amp Internally Regulated Alternators, Sky-Tec High Torque Inline Starter, Roller Camshaft and Lifters, Superior Cold Air Horizontal Induction Sump, Connecting Rods, Balanced Hollow Crankshaft, Dynafocal Type 1 or Conical Crankcase, Ring Gear, Inner Cylinder Baffles, Dipstick and Tube, 90 Degree Spin on Oil Filter Adapter, Prop Governor Adapter and Vacuum Pump Adapter Housing. Port and Polish of the Cylinders, Standard engine color choice


Tuesday, September 26, 2017

M Drawings

Originally, it appears there were 35 sheets but they were later formatted onto 18 sheets.  Additionally, the M Drawings are now posted on the Cozy Builder site.   There are updates to multiple templates. 

Links here:
Cozy Builder CAD files - updated M drawings

http://www.cozybuilders.org/cad_files/Cozy_MKIV_M-Sup_1.2_Draft.pdf

New Sheet      Contents
1   Right, Top Instrument Panel & Top Seatback
2   Left, Top Instrument Panel & Bottom Seatback
2   Right, Bottom Instrument Panel, & M-23 & M-24 Match Pieces
3   Right Bulkheads F-22 and F-28
4   Left Landing Gear 2

4   Left Landing Gear 1
5   Right, Top Firewall
5   Right, Bottom Firewall
8   Fuselage Cross Section - FS 105 to FS 124
6   Fuselage Cross Section - FS 2 to FS 20

6   Fuselage Cross Section - FS 20 to FS 35
7   Fuselage Cross Section - FS 35 to FS 52
7   Fuselage Cross Section - FS 52 to FS 69
7   Fuselage Cross Section - FS 69 to FS 86
8   Fuselage Cross Section - FS 86 to FS 105

9   NACA Templet, Top and Bottom Fuselage Contour Templets
10  Canard Templets
10  Canard Elevator Templets, Vortilon Templets
11  Nose Sections
12 Wing Jig Templets #3, #4, #5 Match Pieces, CS Spar Templets & Winglet Trim Templet

12  Wing Jig Templets #1, #2, #3 & #4 Match Pieces, Rudder Conduit Pattern, & Winglet Root Match Templet
12 Wing Jig Templets #1, #2, #3 & #4 Match Pieces, Rudder Conduit Pattern, Winglet root Match Templet & Winglet Tip Templet
13  Wing Templets BL 67.5, 118.25 & 169 Match Pieces & Straight Templet
13  Wing Templets BL 31, 67.5 & 118.25 Match Pieces & Aileron and Torque Tube Templets
14  Fuel Tank Rib R-33, R-57 Match Pieces & Winglet Bottom Tip Templet

15 Canopy Frame Templets FS 41, 50, 50 & 70 & Canopy Brace
11 Speed Brake Details
16 Engine Mount Front and Side Views
17 Engine Baffles
18 Engine Baffles
18 Carburetor Filter Box


Chapter 03 Education

Chapter 3 is 19 pages long.   It includes a list of basic required tools, recommended tools, items used occasionally & can be borrowed.

Some tools can be made such as sanding blocks, long straight edge, epoxy balance, hot wire cutter, and jig table.

Materials are covered.   The types of fiberglass (BID & UNI), epoxy, foam.

Construction, repair and inspection methods are explained.

Water lines and Butt lines are explained.


----------------------------

The epoxy to glass ratio by weight is typically 1:1.    Wetting multiple layers of glass between layers of plastic on your work bench is often better (quicker and easier to handle) than trying to do one layer at a time.   Exceptions might be for long/hard to handle thin layers of glass.

Typically EZPoxy is used by many builders for the tanks even if they're using MGS for the rest of the structure.

Working time/pot life is greatly affected by ambient temperature.   Warm epoxy has a lower viscosity and wets better.   Warm epoxy can/will exotherm if it's heat isn't dissipated by stirring or spreading out.   Fast hardener is more prone to exotherm than slow.   Several layups (such as the winglet attachment) in the project have many layers and can easily exotherm if the temperature is high and fast hardener is used. 

In cold temps when using epoxy, avoid using heat that produces CO2.  Keep parts above the dew point. Use peel ply to avoid amine blush or amine bloom.  Use heat (lamps or electric blankets) to help provide heat.   See Gary Hunter's presentation on Epoxy.

Wetting multiple layers of glass between plastic is probably faster and easier than doing one at a time and is easier to handle.  A strip of peel ply can be added to this to help provide some additional support to keep the glass from acting like a wet noodle.  This is a photo of 5 layers of 3" x 22" BID, weighs about 2.5 .oz and uses an equal amount of epoxy in weight.  A chart is handy with resin/hardener ratios.  MGS has a green tint.  EZPoxy has an amber tint.   West systems (not recommended for structural use) is clear.

Chapter 02 Section I - Bill of Materials

Chapter 2 is 5 pages long.   It lists the parts and main suppliers.   Below is a link to the ACS site's PDF formatted parts list.

The challenge here is with various modifications, some parts won't be needed.   Some parts may not be available but alternative or better parts are available.

It may make sense to purchase enough fiberglass to complete the project, but order epoxy as needed.   Occasionally there can be delivery issues with items such as MGS epoxy.  Despite expiration dates on some products, if properly stored will remain useable beyond the expiration dates.   See Gary Hunter's EAA presentation on Epoxy.

Shipping charges can become significant for large items.  Sometimes the shipping is more than the cost of the item.  It may be worthwhile to plan a trip to a distributor.   Aircraft Spruce owns Aeroperformance so items can be "store transfers" to those store locations to save on shipping.

Purchasing some components such as the wing core foam that is already CNC cut, adds minimal cost but is likely to improve the quality of the finished project.

Occasionally projects are orphaned/abandoned for a variety of reasons.   These provide an opportunity to pick up finished components for just the cost of materials.  Buyer beware though.


Kit list from Aircraft Spruce

Labeling the boxes of foam with part number, description, size, chapters and quantity needed was helpful.

Chapter 01 Description and Introduction

Chapter 1 is two pages long with a detailed description of the capacity, controls, flight characteristics, design and much other information.  Major sections are:

Description: There are 7 paragraphs describing the Cozy IV.

Introduction:  There are 8 paragraphs.

Building Sequence:  Advises that while waiting for parts, or epoxy to cure, other chapters can be worked on.

Building Time:  Estimate is 2500 hours total time.   (This was before the Internet and a bazillion mods that you'll want to implement).

Questions: Suggests resources if you have questions.

Perspective: "If you modify the airplane and then ask us if your modification will work, we cannot give you an answer without conducting the appropriate tests....."

FAA Licensing procedures:  (Note the procedures may change).

One paragraph advises that that the non-completion rate of homebuilt aircraft is 80%. 

Updates/corrections to plans can be found on Marc Zeitlan's site:

http://cozybuilders.org/newsletters/


Chapter 13 - access clearance for nose gear bolt

Vance suggested removing foam to make clearance if/when the nose gear pivot bolt needs to be removed.   Otherwise, will need to drill a hole in the side if this needs to be removed later.

No automatic alt text available.

Chapter 13 - Landing Brake hidden screw mod


The screw heads were ground flat, notched and recessed similar to the hinge and rudder screws replaced by click bonds.   The regular click bonds shafts weren't long enough.

Chapter 23 - Engine Selection - Prop strike engines - no bueno

In December 2015, flying back from Rusk over Joe Pool Lake at night, I was in the right seat in my friend Don's Comanche, the plane started shaking bad.   We were at 2500' and had just gotten clearance into Arlington's airspace moments before.  Don declared an emergency and the pattern was cleared.   We were SO lucky to be able to turn final and land.   This engine had about 250 hours SMOH from a prop strike/belly landing 10 years earlier.   It had been inspected and rebuilt by one of the largest, "most reputable" shops in the USA.   The crank, cam, 5 accessory gears and one jug had to be replaced on this O-540.  

Prop strike - "dials zero" engines listed for sale did not get my consideration after this event.       

Based on experiences of folks with years of good and bad experiences, and encouragement from some folks that seem to like me, decided to get a new engine.

 


Sunday, September 24, 2017

Chapter 21 - Fuel probes



I had some of Nick's earlier probes that required larger holes to be drilled at the top to help avoid getting clogged with flox.   Instructions are on his web site.  





Princeton modules interface with the probes.

Decided after cutting the first hole that it wasn't the best location.

I used a long skinny small drill bit to make the hole for the probe wire and used safety wire to pull the probe wire through.