Wing Painting

 I really enjoyed painting the wings.  The Stewarts Paint System is fantastic!  You just have to remember to etch the aluminum before priming and painting.  I painted some smaller AL parts and forgot to etch.  The paint does not stick as well.

Installing the Hoerner Wing Tips

 These carbon fiber Hoerner style wing tips increase the total wing span to over 36 feet!  The tips are 18" each, so I decided to install a rib for rigidity to each.

Wing Assembly

 The Bearhawk (Model B Ribblet Airfoil) is pre-assemled at the factory.  My job is to install the fuel tanks, ailerons, flaps, rigging, wing tips...  Prime and Paint!  It took me almost 3 months to assemble and paint both wings.  

Moving Day

 The day has finally arrived!  We are moving the fuselage to the Statesville airport where it will stay until I have completed assembling and painting the wings.  

Tail Feathers and Preparing for Moving Day!

 

Airbox - Multiple Iterations

I originally wanted a conical airbox from James Aircraft to sit in front of the Fuel Servo.  I just could not get it to fit.  So after multiple attempts, I ended up casting a square fiberglass box for a rectangular K&N filter.  That also had some fitment issues, so I reluctantly modified the bottom of the cowling with a fiberglass blister to accommodate the final version.  With this increased filtered surface area should give better flow, and maybe a little more HP?

Gull Wing Doors with Carbon Fiber Frames

 I really wanted a light weight CF door covered in Lexan.  I got what I wanted, but I'm not sure I would do it again.  It was quite a job fabricating the CF door frames.  I lined them with Kevlar to prevent galvanic corrosion and aluminum backers where there will be rivets.  The handle came from Hendrick Manufacturing and are typically used on RV's.  

Painted Engine Cowling Fitted and Installed

 Painted Engine Cowling Fitted and Installed

Installing the Windscreen / Windscreen Fairing (Challenges)

Whoops!  I trimmed the windscreen too short!

The Bearhawk 4 Place uses the Cessna 170 windscreen.  Only slight trimming is need to fit the windscreen to the boot cowl.  My trimming was not slight.  The fix is to enlarge the windscreen fairing and fabricate a piece coving piece for the inside of the windscreen. 

These pictures tell the story...

Fuel Lines ~ Firewall Forward

The firewall forward installation of the fuel lines was very straight forward.  No issues.  I optimized the routing by securing the lines to the engine case/sump with cushioned high temp adele clamps.  

Routing from the firewall goes like this:

1. Port side lower bulkhead fitting to mechanical (engine driven) fuel pump
2. Mechanical fuel pump to forward facing fuel controller
3. Fuel controller (metered fuel) to fuel flow transducer (top of the engine case)
4. Fuel flow transducer to fuel flow divider (spider)

The fuel lines I selected are not the typical fire sleeved lines from most aviation supply houses.  These lines are from TS Flightlines.  Tom Swearingen is the owner and takes great care in consulting with the home builder before assembling the lines.  Tom has purposely designed a better fuel line that is braided in stainless steel and covered (integrated) with teflon.  Just one example of why his lines are superior...  Standard lines are rated to 1,000psi.  TS FLightlines are rated to 3,000psi. 


SPECS....

TS Flightlines Integrated Teflon Firesleeve Fuel Lines

	NEW Integrated Teflon Firesleeve	Standard Teflon Firesleeve (Stratoflex 101)
Conductive Teflon Liner	.030 Wall	.020 Wall
304 Stainless Braid	.006 Wire	.002 Wire
Working Pressure	3000 PSI	1000 PSI
Temperature Rating	-76*/+500*	-65*/+450*
High Temp Silicone Outer Cover	*.060 - .090 Thick	AS1072 Firesleeve

SPECS:

·      Proprietary Design Based on MIL SPECS

·      -3 through -8

·      Made from 304 Stainless Bar Stock

·      Meets ASTM specifications with both MIL and Inspection Reports

·      CNC Machined

·      CNC Mandrel Bends

·      Increased ID past the normal ID average of Stratoflex, Aeroquip, Smiths Titeflex, Teleflex Aero for slightly increased flow.

·      Mandrel Bends maintain a consistent bend margin

·      OD of the body is not increased to achieve a consistent ID

·      Uses a certified nut (Preparing for FAA certification)

·      Proprietary stainless-steel crimp collars

·      Tested to 7500 PSI

(I am not getting paid, just impressed with the product...)

Installing the Hartzell Trailblazer 84" Propeller

I am using the Hartzell 83" Trailblazer composite propellor.  This was tested by Mark Goldberg of the Bearhawk factory (AviPro Aircraft).  Everyone I spoke that has flown behind this prop LOVES it!  Very lightweight and exceptional performance. 

Hanging the prop is fairly straight forward.  Hartzell technical service department was very helpful.  I confirmed a few things with them from the manual.  Prop governor installation and set up, prop hub orientation, safety wiring, etc.  The manual tightening the prop hub to 40 ft lbs each bolt.  There is a bolting sequence to be followed.  You can't do it without a propellor wrench.  Hartzell sells propellor wrenches, but the Ultimate Propellor Wrench works best!  https://antisplataero.com/products/ultimate-propeller-wrench

Detail Painting

 Paint Finishing & Details

New Fairlead for Rear Seat Bracket

 You can see in this picture after installing the rear seat, the left rudder cable rubs against the left rear seat bracket.  These pics demonstrate the fix.

Ignition System - The Magneto vs. Electronic Ignition Decision

If 100 aircraft owners read this blog, I’m certain there will be 100 different opinions on the following subject.  Based on my purpose, environment and mission, this is how I (eventually) came to the decision to use a traditional dual magneto ignition system for the Bearhawk 4 Place I am currently building. 

From the time I started considering the Bearhawk 4 Place quick build kit, I was determined to install a dual electronic ignition system on the IO-540.  I thought, why not?  All modern cars use electronic ignition systems.  Even the FAA has certified a few electronic ignition systems for certified built piston aircraft.  At least partially, with a mag on the other side.  So of course my engine should have EI.  Yes, I want better engine starts.  Yes, I want a smoother running (happier) engine.  Yes, I want the improved fuel burn.  After all, magnetos are ancient history!  Come on people, get with the times!

So I set out to learn more about the Light Speed Engineering solid state EI system (lightspeed-aero.com).  Klaus Savier, President, LSE, LLC, has done a phenomenal job designing and engineering his EI systems.  With 20+ years in service and a great track record, along with Lycoming’s tacit approval of the Light Speed EI on their Thunderbolt engine line (by factory pre-drilling the flywheel for the crank sensor) made for a convincing argument to use this EI system on my IO-540.  

Then, I took a harder look at both the P-Mag (Emagair.com) and SureFly (surefly.aero) magneto replacements.  P-Mag offers a full featured electronic ignition upgrade with a built in power back-up (alternator).  Simply swap out the existing traditional mag with the P-Mag. The SureFly magneto replacement is similar to the P-Mag, without back up power (uses ship power).  

With this information, I’m now leaning towards P-Mag or SureFly EI’s over the Light Speed, mostly because of the ease of installation and all in one units.  Unlike Light Speed that requires multiple satellite components; crank sensor, multiple coil packs, ignition modules with suggested mounting locations on the cabin side of the firewall and, recommended cooling fans.  Oh, and don’t forget the additional 12V back-up battery (another 10+ pounds).  P-Mag and SureFly require much less real estate, additional stuff and weigh less.  I liked that.

Drilling the Wings to the Fuselage

The following is my experience as I learned the process for attaching the wing (root) to the fuselage.  Both main and rear spars come predrilled with 3/16” holes at the root attach point.  The fuselage attachment fittings are predrilled with 1/4” holes.  The end result is to attach the wing root to the fuselage by match drilling the main spar to the front attachment fitting to 3/8” (AN-6), and the rear spar to the rear attachment fitting to 5/16” (AN-5), both left and right.  So we are enlarging existing smaller holes in both the spars and the fuselage to match the aforementioned sizes. 

But first, wings on all airplanes have a set Angle of Incidence.  And the Angle of Incidence for both wings must match each other when installed to the fuselage.  The Bearhawk factory does amazing work building their fuselages and wings.  Their pre-established attachment points are extremely accurate.  However, the wings Angle of Incidence is a fixed design feature that MUST be checked by the builder and can require some fine tuning. 

What is the Angle of Incidence?  On fixed-wing aircraft, the angle of incidence (sometimes referred to as the mounting angle) is the angle between the chord line of the wing where the wing is mounted to the fuselage, and a reference axis along the fuselage (often the direction of minimum drag, or where applicable, the longitudinal axis). The angle of incidence is fixed in the design of the aircraft, and with rare exceptions, cannot be varied in flight.

Wiring and Electrical System

Video from my YouTube Channel discussing the Wiring and Electrical System

I won't get into the specifics of the ignition system in this post, but I need to say what ignition system I am going with for the purpose of understanding what I am wiring.  Because, I previously stated that I would be using a Light Speed dual electronic ignition system.  But I changed my mind and decided I would go with a SureFly electronic ignition on the left side, with a Slick Magneto on the right side.  Then, I changed my mind again...  NOW, I am installing dual Slick Magnetos (6393 retard left, 6350 plain right).  Why?  Because Champion Aerospace offers the SureStart Ignition Booster for their dual Slick Magneto Systems.  They claim engine starts on the 2nd or 3rd blade every time, hot or cold.  I'll explain more when I post the Ignition System blog...

Ok, the Electrical and Wiring process went very well!  But I could not have done it without the help of Jason Smith at Aerotronics.  Aerotronics built my instrument panel and then shipped it to me.  After I mounted the panel and it was my job to bring all of the wires (fuel pump, lights, sensors, battery contactor, P-Leads, etc) through the firewall to panel.  This is accomplished with a 37 pin P1 Circular Connector Plug, a.k.a., the P1 Plug.  Aerotronics prewires the female end of the P1 Plug at the panel.   They map all of the pin locations and then send me the pin map for wiring the male end of the P1 Plug that I assemble.  In addition, based on my choice for a ignition system, Aerotronics also supplied me with a schematic for everything else to be brought through the firewall going to the circuit breaker panel.  It's a full diagram of the entire wiring system firewall forward.  I couldn't have done it without their help.  I read Bob Knuckles book, The Aeroelectric Connection as well as other related books and websites to help me understand the process, methods and technical aspects.

Some of the items that will be mounted to the firewall.