SonexBuilders.net

Hi All,

So I've spent time noodling out the position of firewall items/accessories on Sonex #1339. After looking at many photos, I decided to follow Ryan Roth's example and make a cardboard mockup of my Firewall. I haven't built my AeroVee Turbo yet, so I'm relying on people's previous photos and posts to make sure I don't screw anything up. :P

Anyone have comments about the proposed layout I've pictured below? Note that I have a Filter Capacitor and Overvoltage Protection Circuit that I'm planning on mounting on one of the engine mount tubes (just to keep the wiring from getting too cluttered/crowded on the FW). The only big downside to this layout is that I have to take off the lower cowling to remove the battery - but I'm hoping that actually removing it will be a rare occurrence (since I plan to wire up a charging port).



Can you think of anything I'm forgetting to include? Is my layout going to be a problem for some reason I haven't anticipated? All critique is welcome!

--Noel
Sonex #1339
Center Stick, AeroVee Turbo, TD, Acro-Ailerons, Flush Pulled Rivets

You're not going to have room for the slobber pot (aka the "oil separator") up that high on the firewall. You'll probably have better luck mounting it on the engine mount tubes using Adel clamps. Other than that, it will probably work. Just make sure you can get the battery in and out easily, and can get at the connections without too much trouble.

Noel,

Your fuel fitting will likely not work where you show it due to the rudder pedals on the cabin side of the firewall. You will have to place it higher up on the firewall or place it in between the left and right pedals on one side or the other.

Jake

You may want to consider not mounting the firewall items until the engine is hung. When I upgrade to the turbo on a flying Sonex I had to move the battery box to the right side, the voltage regulator to the side of the fuel fill box, master contactor to the engine mount . If I was working from scratch I would have put everything in a different place from where it is now. Luckily when I removed the gascolator that made room for the spin on oil filter. The other items work where they are,(coils, oil separator, RDAC), but they are much harder to reach due to the turbo, oil lines and exhaust.

Sonerai13 wrote:You're not going to have room for the slobber pot (aka the "oil separator") up that high on the firewall. You'll probably have better luck mounting it on the engine mount tubes using Adel clamps. Other than that, it will probably work. Just make sure you can get the battery in and out easily, and can get at the connections without too much trouble.

Thanks, Joe - I trust your knowledge and opinions here more than just about anyone!

...But... :? I lined it up on the firewall and it seems like it'll fit OK. What am I missing?




OK, so the upper left engine bolt may only be able to go in from the front. But that's not a problem, right? I can't think of anything else that would interfere - I should be aft of the horizontal intake tubes, and above the Starter - right? Is the problem the turbo intake 90-degree bend / down-tube? I thought it would be below that interference area, based on Ryan Roth's images here:
http://www.rynoth.com/wordpress/wp-content/uploads/2015/03/Waiex-2086.jpg
http://www.rynoth.com/wordpress/wp-content/uploads/2015/03/Waiex-2097.jpg

Thanks again,

--Noel

P.S. Jake - Thanks I thought it would clear but upon careful measurement you're right; the position in my original image won't clear the rudder pedals when full left rudder is applied. I've bumped the location to just above the horizontal tube, and slightly repositioned the coils to compensate. I think I can run the line from the tank to the center of the firewall and then snake it past the vertical stiffener and through the firewall itself by using a 45-degree bulkhead fitting twisted to about the 10-o'clock position. I really don't like the idea of running the line in-between someone's feet (i.e. offset to the side of the fuselage like some people do). :P

Couple of thoughts:
1) be sure your fuel run is downhill the entire way. It appears low on the firewall in the pic and may end up running uphill between the firewall and the carb
2) are you installing a fuel flow transducer?
3) the master relay, battery, voltage regulator and starter all have large gauge wiring. Make sure you face them so you minimize the wiring and bends
4) I agree with Joe, mount the oil/air on the engine mount
5) consider mounting the relay on the battery box. I did and it saves a lot of space and wiring mess
6) consider mounting the oil filter on the engine mount. It significantly reduced hose and imop keeps hose away from the turbo exhaust pipe
7) remember that anything you mount on the upper firewall needs to be on with nut plates or you'll have to remove the tank to get to the nuts
8) am I missing your grounding block?

NWade wrote:Thanks, Joe - I trust your knowledge and opinions here more than just about anyone!

Thanks for the kind words. Remember that my opinions are worth exactly what you pay for them!! :)

NWade wrote:...But... :? I lined it up on the firewall and it seems like it'll fit OK. What am I missing?

As Josh mentioned, you have to remember that you can't get at the backside of the firewall up that high once the tank is installed (without removing the tank), so you need to be careful about what you put up there and how you mount it.

I'd echo the opinion not to drill any holes in the firewall until you have the engine hung on the mount with all accessories installed. That doesn't mean that you have to leave the engine on permanently, but you should hang it on there and make sure everything fits and that all your hoses and wires will route in a sensible manner. It wouldn't hurt to hang the engine and fit the cowl before making any final decisions. Don't get too far ahead of yourself.

Noel,
I mounted my oil separator "slobber pot", as Joe said, to the engine mount with two triangular shaped pieces. There is a picture on my photo album from Jan. 24, fwiw.

Sonerai13 wrote:Thanks for the kind words. Remember that my opinions are worth exactly what you pay for them!! :)

As Josh mentioned, you have to remember that you can't get at the backside of the firewall up that high once the tank is installed (without removing the tank), so you need to be careful about what you put up there and how you mount it.

I'd echo the opinion not to drill any holes in the firewall until you have the engine hung on the mount with all accessories installed. That doesn't mean that you have to leave the engine on permanently, but you should hang it on there and make sure everything fits and that all your hoses and wires will route in a sensible manner. It wouldn't hurt to hang the engine and fit the cowl before making any final decisions. Don't get too far ahead of yourself.

Thanks again, Joe.

FWIW, I'm planning on mounting everything on the firewall via Nutplate so I don't have to get at the back-side to hold a wrench for maintenance of any of those items. (I'm trying to steal the best ideas of previous Sonex builders, you see...) :D

The reason I was trying to mount everything now is that I'm a bit paranoid about making metal dust around a completed engine.
I was hoping to finish drilling all holes and cutting before I start doing engine assembly... Maybe I should just clean part of the workshop, focus on the engine enough to get her closed up, then cover her with tape & shop towels. :P

JJ - Yes I have an FT-60 ("Red Cube"). I know what the instructions say about its placement; but you can't have both the cube *and* the AeroInjector be the lowest spot in the system! :roll: My plan has been to ape one of the SonexFlight hosts and put my FT-60 on the fuel tank, just beyond the fuel shutoff valve. If it gives me trouble I'll move it to the firewall, but right now my attitude is that the more components of the fuel system I keep out of the heat & clutter of the engine-bay, the better. 8-)

Quick Q for those saying I should hang the engine first: With no wings on a (taildragger) Sonex, do I need to weigh the tail down to keep it from tipping onto the nose?

Thanks all,

--Noel
Sonex #1339

I mounted my engine while the project was at home before the wings were fitted and had no problem with the tail coming up.