R

ron sterba

Well Known Member
Just ready to drill holes thru firewall for mixture and throttle cables. What did you find that would keep the fumes from entering the cabin as well as simplicity for angling. Where did you buy them? Whats a Fair price do you think.

Happy Thanksgiving everyone.
Ron in Oregon RV9A
 
ron sterba said:
Just ready to drill holes thru firewall for mixture and throttle cables. What did you find that would keep the fumes from entering the cabin as well as simplicity for angling. Where did you buy them? Whats a Fair price do you think.

Happy Thanksgiving everyone.
Ron in Oregon RV9A
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Either work. The cover plate is significantly less expensive.

I basically followed Van's plans with a bushing, then added a stainless cover on the firewall. I then used 3M Firewall 2000 Sealant to plug any open spaces or gaps to keep the CO out.

Make your decision before you drill the holes. You may want the holes further a part than the plans call for depending on the device you use. I learned that lesson the hard way.
 
I used these conduit pass through a from the hardware store, they make all sizes for less than $1 a piece. A doubler on the firewall, 3m fire sealant in the middle and wrapped with fire sleeve on the engine side. I couldn't get myself to spend the money on the aviation passthroughs, no test but its got to be better than just a plastic bushing and rtv. Easier than drilling a hole through a bolt as described in "firewall forward."
ED171650-672F-450D-AD41-69116DA94802-1105-00000076AA26C7A2_zps1aa97eda.jpg

Pic of a larger on for EI stuff prior to sealant in the tube and fire sleeve on the outside. Sorry no decent pics of throttle/mixture cables.
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On the Van's RV14 Walk Around Ken stated that Van's has some nice pass thru items for the RV14. Might check them out. :)
 
Avery offers some nice stainless steel firewall penetrations that reportedly have been backed up with testing. http://www.safeair1.com/averytools/firewallpassthrough.php

I've used these on several experimentals but no actual fire tests :D They aren't cheap but are quality products. The largest one will allow the D-sub connector for LSE's control box to just make it through the fitting.

McPherson_FPT_10.JPG
 
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crabandy said:
...but its got to be better than just a plastic bushing and rtv.
ED171650-672F-450D-AD41-69116DA94802-1105-00000076AA26C7A2_zps1aa97eda.jpg


I was going to let this go as 1) I'm new here and 2) haven't yet started my 14...but these ZA alloy pass throughs will melt at less than 800F. I personally wouldn't drill a big hole in my firewall for something that will become a puddle of molten metal in my lower cowling very quickly in a fire. I doubt if certified airplanes have zinc firewall fittings; why should we settle for less security?
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Cut a 2" x 2" steel plate, drill #30 holes in the corners. Drill the center for whatever size tube you want. Weld a 2" length of that tube into the plate. Smear a little FireBarrier 2000 on the back of the plate and attach to the firewall with SS rivets. Install whatever runs through them, then pump the core full FireBarrier.

Fireproof, waterproof, and gas tight....and they cost about 50 cents to make.

30t43n9.jpg


Tested? Start at post #38

http://www.vansairforce.com/community/showthread.php?t=72087&page=4
 
^^^^ This looks like a quality solution to me ^^^^; these are the essence of what Avery /Safeair1 are hawking.

I'm all for Lowes Aviation Department, but not using ZA fittings as a heat barrier.
 
Vlad,nice job,that's exactly what I wanted they have one for each cable. card heat spiralled & throttle/mixture cable. I'll drive up in the morning. Half hour drive..thanks,Have a nice Thanks giving Ron in Oregon
 
Go with the steel pass-throughs. They are expensive, but work great. I got these from Aircraft Spruce. They have different diameters that you can order, so make sure you get the right ones for your cables. I put the holes on the firewall recess instead of down low where Van's has them on the plans. This keeps them up above your feet in the cabin and works just fine.

IMG_3821-M.jpg
 
Order the correct size opening

Ron,

Yes, I think that is the same steel pass-through, but shows only one size which "can be drilled up to" whatever... I spoke with the man who makes these and he said to drill that steel ball would be very difficult. AircraftSpruce sells the variety of sizes to fit the different cables and even has a chart to show which ones to use with each cable.

Hope this helps!
 
Speaking from experience, the 'drill to size' option sucks. But I like the idea of steel much better than aluminum, so I was a little more diligent for the RV-10 and got the right eyeballs. I forget the source but someone was just recently asking about dimensions for a similar product that looks a little better than the ones I found.
 
The ones from ACS and Van's are the same make. ACS has multiple diameters listed that you can order. I got the .26 for the throttle, mixture and purge valve. I had to drill out ever slightly the hole for the purge valve cable and it was challenging enough. Had to clamp the thing down real well on the drill press and go at it gently to keep the bit from catching on the split halves. I broke the drill bit the first time I tried without clamping everything securely down.
 
ronschreck said:
I used to use these then found that they were very difficult to disassemble without ruining them when it came time to replace worn cables. I ended up with the steel SE961 (AC Spruce Part No.) pass throughs and will never go back.
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Amen, I loved these at first but learned to hate them later. I will never use those type again.
 
Hi Melinda, I followed Vlads lead too on the balls in the plate. I went to Vans this morning and bought one steel ball/plate that fits the spireled carb heat cable and two of the aluminum ball in the steel mounting plate. NONE of the twist on blue collar. I can drill the aluminum to my mixture and throttle cable. The aluminum balls are about 7/8" in diameter and have a 50 degree tilt up and that should work perfectly. I also like throwing money at Vans employees, they are all so dedicated folks, mean it!. I figure if there a fire up front i feel the sides of the aluminum fuselage will melt first before 7/8" ball of aluminum. Vans has a plastic bushing with RTV covering the cable and bushing. If that little RTV melts you had better be on the ground because theres a whole lot MORE going on up front. This has been a good thread.Happy Thanksgiving,Ron In Oregon
 
Firewall Pass Throughs

For throttle, mix, & gov control cables I tried Van's bushing method then rubber grommets with shields. The bushings did not give a tight fit to the cable and would need fire stop to seal them. The grommet for the gov cable also distorted badly because of the oblique angle the cable came out at and would. These would also need fire stop as rubber is still exposed. I considered Van's & ACS's eyeball penetrations, rejected anything aluminum as I believe Canadian MD-RA inspectors don't allow it, and the SE961-S because it only goes to .260" - the cables measured .335" max/.332" min. Also considered Dan Horton's method but don't have a welder. Ended up using Doubletee TTP 7100-333 eyeballs - $37.50 ea. Ted Teach already had 2 made up, bored one more and got three out the day after I called - great service. These sealed nice & clamped the cable well, and allowed for the oblique pass throughs.

For electrical I used SafeAir1 pass throughs. Nice but also expensive.

For Bowden cables I plan on using Bowden cable clamps - like a bulk head fitting on the firewall. Van's have not seen this & I haven't done it yet so can't comment on how good it works.

Picture below:
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Hey Melinda, I found a little trick to drilling those holes out larger. I think my hole in the ball came as a 1/8" (two halves put together drilled out 1/8") Using my drill press. I placed my CLAMP DOWN vise on the drill press table. Then I inserted 1/8th" drill into the chuck and tightened. I drew down the drill/chuck several inches. Then I slid my (assembled eyeball/frame together) eye ball up onto the drill so it went thru the ball. This gave me my drilling alignment. Brought my table up and CLAMPED my eyeball assembly into the vise.Then retracted my drill/chuck out of the ball. Then opened the chuck WIDE open to remove 1/8" drill bit and then using three larger size drill bits and cutting oil made the eyeball hole to fit my cable which was .265". Fit perfectly. I still haven't found a good way to cut a 1& 1/8" hole in the stainless. Any hints? I too bought the Doubletee brand from Vans, nice assembly plus its just a 30 min drive to Vans from my place.
 
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Step drill

Well, I drilled a small pilot hole (with cutting oil on the bit) and then step drills with my hubby holding a piece of fairly thick aluminum on the back along with a block of wood that had a hole already in it to stabilize the firewall... I'm sure others can chime in with perhaps better and easier ways to get big holes in the stainless!:D
 
I've used step drills and fly cutter with good results on the firewall, again well supported behind with a block of wood clamped on firmly.
 
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