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And so it begins

For radio people like us there's no simple...just choices given the low power levels found in aircraft vs desired signals. So, yes is the Executive Summary. The aircraft tests are what's required for certification. RF power and location vs possible interference to other aircraft systems.

Gary
 
IMG_7316.jpegIMG_7314.jpegFinal fitting forward floor and kick panels. Riveted the fuel selector panel on. Welded up an aluminum heat duct. It Y’s down under the floor to connect to a duct that pops back up under the pilot seat and then connects to an eyeball vent for the rear seat heat. The Y diverts about 1/3 of the airflow.
 
Installed Vista vents in both swing up windows and finally got my throttle cable hooked up. Been spending most of my time on fuel/oil lines forward of the firewall and brake lines stubbed out the belly. The little stuff takes way too much time. Had to order a new mixture cable after I cut it about 1.5” short. If anybody needs a mixture cable that’s 46” long send me a PM.IMG_7319.jpegIMG_7318.jpeg
 
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Finished my firewall forward fuel & oil line installation. I changed a few things around from my original plan. Moved the gascolator and built a new mounting bracket which allowed more efficient fuel line routing. The engine was delivered set up for the fuel line from the front of the servo to the spider going up between the #1 & #3 cylinders. I put on a Vetterman exhaust and the crossover pipes clearance from the oil sump was a bit snug for fuel line clearance. Fortunately, the Silver Hawk servo has the option of moving the fuel output port to the rear. That allowed me room to mount the fuel flow cube and route the line around the back side and over the top of the engine. Oil cooler is mounted and plenum installed. I fabricated a pre-oiler and pumped in a gallon of heated oil and pressurized the oil system…no leaks.IMG_7372.jpegIMG_7372.jpegIMG_7360.jpegIMG_7348.jpeg
 
Just curious but is a fuel line that goes up and over the hump susceptible to vapor lock?

Glenn
Yup, unless there is enough head pressure to maintain the flow. Had this issue in a T-craft wing tank with a slight rise in the fuel line. Gravity couldn't overcome the air bubble unless the wing was raised and a slip forced the flow to start again.
 
Vapor lock is a concern. Considering the line was delivered going between 1 & 3 cylinders I would assume there is a significant amount of heat generated in that small space. Here are a couple shots of the routing now. There are no high spots in the line for air to trap. It’s sloped up all the way to the spider. Granted, the slope is shallow from the baffle to the spider. Im told there are other certified aircraft that route the fuel line above the engine to the spider. All things considered, this was the best routing I could come up with to avoid the original problem of fuel line and exhaust pipe in close proximity.

The brown line is an Aeroquip that has an integrated fire sleeve. That’s the line that was supposed to go straight down from the spider between the jugs.
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Awesome build. You are a very talented builder. A lot of things in front of that firewall.

I suggest cutting all to zip tip tails with a flush cutter.
And changing those exhaust bracket steel clamps for shorter ones.
Those can do some unwanted skin cuts.


Do you have reinforcement doublers behind the firewall cowling mounting brackets?
I had added those on my plane because the firewall flange has developed a small crack...

pic from this forum:
20190819_163531.jpg
 
Awesome build. You are a very talented builder. A lot of things in front of that firewall.

I suggest cutting all to zip tip tails with a flush cutter.
And changing those exhaust bracket steel clamps for shorter ones.
Those can do some unwanted skin cuts.


Do you have reinforcement doublers behind the firewall cowling mounting brackets?
I had added those on my plane because the firewall flange has developed a small crack...

pic from this forum:
Oli,
Thanks for the suggestions. I've been eyeing those clamps thinking I need to cut the extra material off. My hands and arms look like they've been through a meat grinder from all the stuff that catches on you in tight spots. I've been cutting the zip ties with a side cutter, didn't know they make a flush cutter. I'll have to do a search on the internet.

I do have the half moon shaped doublers on my firewall cowl mounting points. What I did differently is I left off the angle that mounts to the back side of the firewall and rivets to the boot cowl. My boot cowl is in three sections and I wanted to be able to pull off each section with screws. I could have put nut plates in those L brackets but instead fabricated diagonal braces from the same points the L brackets bolt to that anchor at the other end to the aircraft tubing. I've seen other cub types that cracks in the boot cowl around where the L brackets are riveted. Hopefully my method will eliminate that issue and not create other problems. That firewall flange was a booger to make, took 5 attempts, so I'm hoping I didn't move the stress points to that flange.
 
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Plugging along. Installed the D window trim and a valve for the belly pod. I put a check valve in the line after the shut-off valve to prevent and flow back to the pod. Reinstalled the forward floor, hopefully for the last time, as well as the rudder/brake pedals. Hooked up the park brake but my planned routing of brake lines is not going to work out. So I’m still scratching my head on that.
 
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Plugging along. Installed the D window trim and a valve for the belly pod. I put a check valve in the line after the shut-off valve to prevent and flow back to the pod. Reinstalled the forward floor, hopefully for the last time, as well as the rudder/brake pedals. Hooked up the park brake but my planned routing of brake lines is not going to work out. So I’m still scratching my head on that.
where did you get he carbon fiber window trim?
 
where did you get he carbon fiber window trim?
I made it. I traced the profile onto poster board then used that as a pattern to cut a thick piece of plywood to use as a mold attached to a melamine table. Vacuum bag and presto, you have a part that you’ve spent 8 hours building and trimming that you should be able to buy for $20.
 
Are the carbon fiber fairings over the elevator pulleys just screwed into the carbon fiber floor? I'm trying to figure out a way to attach covers to the floor - thought I might have to bond something to the floor to attach them.
I used Clickbond floating nut fasteners. They use adhesive to bond to the underside of the floor. Work great but make sure you run a tap through them before bonding to the surface. Same with riveted nut plates.
 
I used Clickbond floating nut fasteners. They use adhesive to bond to the underside of the floor. Work great but make sure you run a tap through them before bonding to the surface. Same with riveted nut plates.
Nice, thanks for the info!
 
keep weight in mind, it adds up quick. Sheet metal screw into the floor holds the pulleys on fine. If the hole gets too big you can dab in some jb weld or something of the like and re screw. these airplanes are simple, keep them that way
 
keep weight in mind, it adds up quick. Sheet metal screw into the floor holds the pulleys on fine. If the hole gets too big you can dab in some jb weld or something of the like and re screw. these airplanes are simple, keep them that way
You're saying sheet metal screws in a carbon fiber floor have been no problem? I would like to keep it simple - I didn't try just assumed it would be weak since it's just that thin layer on top of the core foam.
 
You're saying sheet metal screws in a carbon fiber floor have been no problem? I would like to keep it simple - I didn't try just assumed it would be weak since it's just that thin layer on top of the core foam.
1000 hrs or so in and take them off during the annual. You can use 4x6 stainless they will grab into the foam
 
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Big event today…A buddy helped me get the main gear under the project. Might not look like a major accomplishment but it feels like one. I have 31’s for it but it won’t fit through the shop door with those on so 8.50’s for now. The plan is to build covers, aluminum or carbon fiber, for the gear legs but that’s for a later date.
 
Made some progress over the last couple days, after a week on the road. I made my safety cables, fabricated a long step and modified a motorcycle foot peg for a step at axle height. That will be handy when it goes on the 31’s.IMG_7485.jpegIMG_7481.jpegIMG_7479.jpeg
 
Can you reach over the leading edge of the wing when on that step? It looks tight/short.

It sticks forward of the gear tube 7”. I’ll let you know if that’s enough when I get the wings on. I assumed it would be adequate since the fueling step on my left gear is welded on the gear tube as others have done.
 
When you are in 3 point attitude the leading edge is back quite a bit depending on gear length and tires. I have no problems with mine.
DENNY
 
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