2024 AVC Race Prep

6/16/2024 - AVC race prep.

There's a bunch of administrative stuff to do such as provide a Certificate of Insurance, Log Book entries, copies of Airworthy Cert, Operating Limits, Registration, ELT Battery dates etc.  The planes don't fly unless the paperwork equals the weight of the aircraft!  

Technical items to address:

Leading edge tank drains - remove (I have lower sump drains that are less draggy).

Fuel vent lines are sticking down 1" on each side under the strakes.

Cowl and cover seams.

Winglet / wing fairing. - Notes from one of Mike Arnold's videos indicate a radius of 6% of the wing chord is optimal.   I've been referring to Berkut13's site:  https://www.berkut13.com/berkut61.htm#wfair

Wheel pants - need some finishing work to smooth/reduce drag.  

Top mounted oil cooler exhaust fairing.

2000/3000/polish on clear coat. 

Order and apply Race numbers.   - Found a supplier in Georgia via Amazon.  They were 1/3 what a local shop wanted.

Spinner - I have a "Hershey Kiss" spinner that needs finished.   After watching some of Catto's recent prop videos, am tempted to add some small fins to it.

Strake/wing fairing.

Canopy seam - see video below.  (V-seal and Tesa Tape). Looking for gap seal solutions, found this video:

Dave Anders has written several articles on drag reduction and other performance mods.  An article here has a few more items to consider:  https://www.kitplanes.com/so-youd-like-to-go-faster-2/

6/9/2024 Cozy time for a new owner. Miscellaneous squawks.

 A new Cozy owner needed some stick time for insurance purposes.  He's flown a variety of aircraft and is an ATP.  He used to own a T-18 which can be a handful to land, so the Cozy will be pretty easy for him.  We flew to three different airports and he did pretty well.  My neighbor is renting him temporary space for several months.  Hopefully, he'll retrieve his Cozy next week.

During the flights, a few gremlins popped up:

The canopy latch circuit was intermittently showing the canopy open.   Suspect the magnetic switch on the canopy is failing again.

On the last two landings, one of the main wheels had some shimmy, suspect the brake caliper was hanging up a bit.

The fuel levels displayed on the Dynon panel seem higher than what's in the site gauges.  Suspect adding MMO to the fuel has changed the dielectric constant.  May need to recalibrate the gauges. - Update - I think issue is that I had long beaded chain connected to the gas caps and it had slid under the probes.  The anchors were hanging down to far and would slide through the lower baffle holes.  I fished the chain and anchors out and shortened the chains and moved the anchors closer to the caps.   The probes seem to read correctly now.

The light colored Zolatone in the cockpit is making it difficult to read the adjacent panel due to shine/reflectivity.  Probably should get some "dash mat" and put in the strakes.

An email from the AVC (Airventure Cup Race) says I need to pick a new number, so replied with three choices that weren't already reserved.

My wife reminded me that the back windows still need tint.   

I need to work on my "speed list" for some small fiddly stuff that should be addressed to gain some micro-knots.

Upholstery

Seat foam (soft and medium soft remnants) was ordered from Dynamic Systems and arrived yesterday (Monday 4/8) .  I have some medium left over from a friend's project and will use some of that too.

 Remnants are available from Dynamic Systems (Sunmate):  https://www.sunmatecushions.com/

Video on shaping seat foam:

 https://www.youtube.com/live/dxDqKdkmGuk?si=Tg8sgZy9qLBDF_eI

My wife wasn't fond of me buying a sewing machine.  Youtube was feeding me video suggestions from https://www.youtube.com/@oldschoolautoupholstery  and he is located at Livingston TX.  The airport is 00R (Zero Zero Romeo).  Richard said he'd be available after April 14th to work on the seat covers.

Template for the back seat.

Passenger seat foam laid out on the wing.

Variation from plans on the thigh support is to cut a round or rectangular edge to make it easier to slide feet under the panel.

Front seat template. Thigh support is shortened and narrowed some.

Pilot seat foam and headrest pad.

Head rests for passengers will go on the battery cover.

Pilot and Copilot headrests will attach with Velcro or snaps.

Update 6/7/2024.  Richard Rudolph (Rudolph's Upholstery in Livingston TX) had the seats ready so I picked them up today.  He made a video here:  

The seats are comfortable and need some minor tweaking.   Now the old pads can go back on the patio furniture!  

Vance's Cowl Inlet Door and vented top cowl

 Vance Atkinson implemented an adjustable NACA inlet lip.   Also had vents above the #3 & #4 cylinders.  IIRC, he said the cylinders were about 15 F cooler by adding the vents.   The adjustable lip was only effective to a certain point but did help cooling on take off and reduced cooling drag in cruise.

Buss switch left on/voltage warning circuit.

A common method used to prevent a dead battery is to visually indicate that the master switch was left on by leaving the strobe switch turned on.  The shortcoming with this method in N724CZ is that the strobes and non-essential equipment is powered through the VPX and that gets it's power when the master switch is on.

The nose gear actuator gets its power from the essential buss, so when the nose needs to be raised or lowered on the ramp, the essential buss switch needs to be on.

I don't want the warning buzzer going off when I'm preparing to start or shut down the engine so my logic is:

If a fuel pump is running, don't buzz.  The pump makes enough sound, it's obvious a buss is energized.

If the fuel pump(s) aren't running and essential buss is energized then buzz.  Either we're preparing to start or momentarily lowering or raising the nose.

To simplify the logic, the buzzer will be powered by the essential buss.  Then two inputs are needed that sense if either fuel pump is energized.  

www.homemade-circuits.com/how-to-make-logic-gates-using-transistors/

The NOR gate in the article above  will work with the A & B inputs connected to the positive posts of each fuel pump.  The buzzer circuit's ground will connect to output "C" and the positive source for the buzzer will connect to the essential buss.

It might be nice to have a 15 second mute button.   The points where a battery charger are connected will need to be on the source side of the master or buss relays to avoid energizing the buzzer.