Is your Guillotine Firewall Slide completely CLOSED

How to keep the Cessna 170 flying and airworthy.

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MoonlightVFR
Posts: 624
Joined: Sun Jan 02, 2005 5:55 pm

Is your Guillotine Firewall Slide completely CLOSED

Post by MoonlightVFR »

I think there is an ongoing story.

A picture of the the slide door assembly was posted. Thank you Bruce.

I noticed a residual deposit "dark" at top of door in Bruce picture - appears about 5/8" stripe.

Now I am concerned that many owner operators of C 170 /172 /182s are flying with slide door not COMPLETED Closed. Thus subjecting the Cabin Occupants to immediate CO poisoning IF a muffler or various exhaust items suddenly crack.

When Slide door is closed sealing off the firewall the bowden cable really looks strange with such a Big protusion from the dash.

What is this? the normal position extending nearly 4 inches from the dash? Really?
gradyb, '54 B N2890C
hilltop170
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Re: Is your Guillotine Firewall Slide completely CLOSED

Post by hilltop170 »

That dark stripe is where dirt and other stuff collects because the slide valve is not fully open. It's not an indicator of whether the slide will fully close.

I fly with my slide door completely open. I think fresh air/air changes coming into the cabin all the time is important. The slide valve to me is to be used only in an emergency when it needs to be closed for some reason. I check the operation on a regular basis and insure it closes off the air flow completely by checking air flow from the discharge vents. Mine seals completely. The control knob does look very strange when pulled completely out/closed. Another reason I keep it pushed in, if that control is accidentally bent while out/closed it won't operate at all.

When my A-Model 170 heater was converted over to the later style, the slide door was not installed for some reason. Thanks to Del Lehmann at Mountain Airframe, LLC, who installed it later, I finally feel much better in case it is ever needed.
Last edited by hilltop170 on Sat Feb 23, 2019 3:33 am, edited 1 time in total.
Richard Pulley
2014-2016 TIC170A Past President
1951 170A, N1715D, s/n 20158, O-300D
Owned from 1973 to 1984.
Bought again in 2006 after 22 years.
It's not for sale!
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GAHorn
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Re: Is your Guillotine Firewall Slide completely CLOSED

Post by GAHorn »

hilltop170 wrote:.... That's another reason I keep it closed, if that control is accidentally bent while out/closed it won't operate at all.....
Didn't you mean "open"?

When I told the story of last year when I picked up a New Training Plane … the 172C that I flew out ahead of a storm to my place in order to inspect it... Taking off into storms and feeling cabin heat and smelling exhaust gave me the Decision to make.... (Immediate return and live in an arriving hurricane? or go somewhere else with it)…
... the prudent decision to return was complicated by the TRWs in the immediate area and clearer wx a few miles away... So I tried to shut off the cabin heat.

No can do.... the knob was all the way "in" and cabin heat was not closing. 8O

The often-ignored/rarely-checked cabin air Shut-Off (Guillotine) was tried...and THANKFULLY it worked! Otherwise I'd be dealing with exhaust fumes and cabin heat entering the cabin and disallowing any options to me. While desireable, that spring is not as important as the condition of the bowden cable and valve-sealing and the ability to SHUT that guillotine valve in flight.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
Hineywheel Bill
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Joined: Fri Feb 17, 2006 8:55 pm

Re: Is your Guillotine Firewall Slide completely CLOSED

Post by Hineywheel Bill »

While doing the annual inspection last month, it occurred to me that I had never operated that air door since buying the airplane last year. It worked as advertised but I took that as a reminder to check it's operation occasionally. That was also a good time to lubricate the spring (for corrosion control) and all the cables.
Owner of:
1954 C170B N1921C S/N 26066
Former owner of:
1948 C170 N3815V
1951 C170A N1490D
1946 C140 N76447
hilltop170
Posts: 3481
Joined: Sat May 06, 2006 6:05 pm

Re: Is your Guillotine Firewall Slide completely CLOSED

Post by hilltop170 »

gahorn wrote:
hilltop170 wrote:.... That's another reason I keep it closed, if that control is accidentally bent while out/closed it won't operate at all.....
Didn't you mean "open"?
Yes, I corrected the original post.

As far as closing the slide valve with the heater on, I seem to remember the Owner’s Manual specifically warning not to do that.
Richard Pulley
2014-2016 TIC170A Past President
1951 170A, N1715D, s/n 20158, O-300D
Owned from 1973 to 1984.
Bought again in 2006 after 22 years.
It's not for sale!
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GAHorn
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Re: Is your Guillotine Firewall Slide completely CLOSED

Post by GAHorn »

hilltop170 wrote:
gahorn wrote:
hilltop170 wrote:.... That's another reason I keep it closed, if that control is accidentally bent while out/closed it won't operate at all.....
Didn't you mean "open"?
Yes, I corrected the original post.

As far as closing the slide valve with the heater on, I seem to remember the Owner’s Manual specifically warning not to do that.
The heater wasn't on. But heat/exhaust fumes were entering the cabin. However, if the heater were on...and exhaust were entering the cabin and the heat could not be turned off.... I'd still pull the air shut off regardless of what that Owner Manual said as their concern over hose-damage would be the least concern. :lol:
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
hilltop170
Posts: 3481
Joined: Sat May 06, 2006 6:05 pm

Re: Is your Guillotine Firewall Slide completely CLOSED

Post by hilltop170 »

Agreed, I was just pointing out that heater-on, slide valve-closed is not recommended.
Richard Pulley
2014-2016 TIC170A Past President
1951 170A, N1715D, s/n 20158, O-300D
Owned from 1973 to 1984.
Bought again in 2006 after 22 years.
It's not for sale!
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