Cowl / Firewall questions

[High Country 69]

So I'm working on fitting up my firewall and cowl and have come up with a few questions. First I see on Leni's pics the firewall is flat on mine it has several bends (see pics)I was thinking I could make the bottom bend be more forward giving more leg room but to do this I would have to cut out the bottom of the cowl to rotate the exhaust forward. I can't find anything that would be a problem doing this. I have a new sheet of stainless to make a new firewall with. next is where to put my radiator(s) I don't like the original design of hanging it out the side. Is it better to do the two side by side in front or single down low? any pics of both of these being mounted and plumbed in would be great. how exactly was the cowling different on the C vs B models. I have the two piece that splits L and R, I was thinking of attaching them together and cutting it in half on the sides so as to eliminate the ugly seam on top. what would be my best method of doing this, also would it be beneficial to cut the back off and make the back portion into a boot cowl? I'm not really sure why everyone has gone to the boot cowl design, seems to me that by removing it all in just two pieces gives you better access to behind the instrument panel. and lastly (for now) seeing as i have a very tight area to work with what would be the best master cylinders to use i was thinking the Matco MC-4D, yes-no?

-Robert-

-sorry for the big pics I can't seem to figure out how to make them smaller-

Edited 10 May 2012 by High Country

[efil 01 74]

hi robert,

what type of radiator do you want to use?

my plane is exactly the same as your and is in the same step of building process.

i keep original C cowl, better look for me and is more aerodynamic than MK4 cowl; then i go for belly mont of radiator.

about leg room, you will note by sitting in the plane on tubes that you can have plenty of leg room if you modify a bit the seat.

sorry i don't have pics of my mod and i'm not working on the plane those days; and my plane is 40km from home

manu.

[High Country 69]

hi robert,

what type of radiator do you want to use?

manu.

I think I would like to go with the belly radiator but was wondering what is the best set up. seems like its pretty tight space either way I go. I was hoping go see some pics of both and see what you guys think is best. what is the measurement from the bottom of the opening on the front (below the prop) down the seam to where it ends. I'm planning on cutting out a big chunk of the bottom to pull the exhaust forward and need to know how far to cut to. some pics of this area would be great especially if the exhaust and belly radiator are installed. I believe this is the same set up that Joey has.

-Robert-

[dholly 718]

- My Avid Mk-IV cowl was 2-pc, upper and lower.

- My KF III and KF IV-1200 cowls are 4-pc, upper and lower main body plus upper and lower ring cowl.

- My Aerotrek cowl is 2-pc, upper and lower plus fixed boot cowl.

- Mk-IV cowl easy on/off, great access to back of panel.

- KF cowls are P.I.T.A., ie. you must remove front ring cowl pcs before you can remove the main pcs. My KF III cowl had an oil check door, my IV-1200 does not (yet). For now, I must remove both top cowl pcs just to check oil level.

- Aerotrek boot cowl is a single fixed piece that includes top and both sides. Zero easy access behind the panel, seems like the stupidest thing ever to me.

- My Avid+ will have a 3-pc cowl set, one single lower cowl that extends to the door posts and a 2-pc top cowl, large main top plus small removable top boot cover for access to back of panel. Easier to do this now than trying to work up under the panel on your back in a cramped cabin. The small top boot also allows for better rain protection for your instruments when you top cowl is removed and may allow for a more effective or permanent weather-tight seal between windscreen and cowl. When it rained, my feet got wet in my KF III, lol.

[edit] I thought the B and C models both used the vertical split cowl?? Don't think you can fit the two internal radiators under that cowl, that's one reason the Mk-IV cowl was redesigned with front air openings. I know a few who fitted Mk-IV cowls to their C models to use the internal radiators and are happy with the result. No cooling issues whatsoever. Personally, I'm not a fan of the external radiators aesthetically but sometimes you just gotta do what you gotta do. External mounting is easy and very flexible re: forward/backward positioning. I have attached some instructions from my KF manual for positioning with a scoop, might be helpful.

Radiator 001.pdf

Edited 10 May 2012 by dholly

[Av8r3400 1179]

Doug - You can remove just the upper (back) cowl without removing the top of the ring on a 4-piece Kitfox cowl.

[dholly 718]

Hmm... Larry, now that I think about it a little bit, I'm sure you're correct. I admit to only trying it on my model 3 which had a panel tank with fuel filler through the upper cowl. I can see how the lack thereof on the model 4's would require significantly less finagling. I will give it try, thanks!

Still a fan of oil doors though!

[Av8r3400 1179]

Oil door is way much more gooder.