Thorp Air Command - T18.net

I'm using the 1" scat hose from the leading edge of the wing to eyeball vents instrument panel mounted. In flight, you have to turn them off to open a chart. Deb and I turn them down at altitude because there to cold.

I was hoping for an easier solution than putting vents in the wing as a retrofit to a flying aircraft. Gaining access to the inside of the wing and cutting holes to route scat tubes seems like a pretty big project to me. The bottom of the cowl may be a better solution in my case.

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Thorp T18
O-320-B3B (160 HP)
68x74 Sterba Propeller

"The joke in aviation is, 'If you want to make a million, you'd better start with £10m.' " -Bruce Dickinson

I think Unclerap has a T18 with vents cut out on each side of his sliding canopy. I know the cowl exits are just in front of that area, but I wonder if you get hot or cold air into these canopy vents? Maybe send him a direct message to find out.

I put my NACA scoop on the bottom cowl (per an OLD NL write up) scat tube to a diverter box on the firewall and then from the inside a single hose to a "Y" splitter fitting , then via scat tubes to 2 eyeball vents on the dash .

RB

The wing vents can be cut in the wing gap covers. No need to demount wing.

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Bob Highley
N711SH
SN 835
KLAL

I don't see how it could be done without pulling the wing and/or installing some access panels. I have no lightening holes in the ribs in front or behind the spar and only one recently installed access panel in the entire wing. Kinda makes it a challenge to route the scat tubing.

The cowling option seems a lot more friendly to install.

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Thorp T18
O-320-B3B (160 HP)
68x74 Sterba Propeller

"The joke in aviation is, 'If you want to make a million, you'd better start with £10m.' " -Bruce Dickinson

If I had it to do over I would not have installed the air diverter/mixing box on the firewall . The fresh air would have been piped directly to the eyeball outlets with a shutoff valve on the cockpit side . My engine plenum is so efficient it pumps a lot of hot air thru the heat exchanger and the metal to metal contact inside of the mixing/diverter box does not make for very effective sealing off of the hot air , so some bleeds thru even when I select full cold . I still get cool air , but not as cold as I would like it . I know it's not Burger King !

RB

If you don't want to mess with cutting holes in multiple ribs, why not cut a hole in the leading edge inboard of the first rib (between the first rib and the fuselage)?? That area will then be pressurized forward of the main spar and inboard of the first rib. Cut a hole in the fuselage forward of the main spar and you will have good airflow coming in below your knees on the lower sides of the fuselage. You can install a small rotating door to shut off the airflow and it is all doable without butchering an existing paint job. The most you will have to touch up is the paint around the perimeter of the leading edge hole, which will be minimal if you are careful . It works great on my installation!

That is another option worth looking into. There is a picture of a vent installed next to the fuselage on the first page of this thread but I had dismissed it because it was with pictures showing a rib in the way. I should have studied those pictures a little more. Looking at them now I realize the pictures showing the inside are for a different location.

As far as the cowl option, I have 2 cabin heat boxes on my firewall. Both come through at the rudder pedals. Only one is connected so I could use the other one for cool air.

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Thorp T18
O-320-B3B (160 HP)
68x74 Sterba Propeller

"The joke in aviation is, 'If you want to make a million, you'd better start with £10m.' " -Bruce Dickinson

I have a scoop similar but shorter than the Cessna 150 carb heat air inlet on the right inlet of the cowl. I have a 1 1/2" or 1 1/4" hose going through the lower firewall and then up to two eyeball vents on the panel. I have lots of cold air with this set up.

Jim

I was wondering how well a 150 style scoop would work.

Everyone, Thanks for all the input. I got a lot of good ideas for both retrofitting the aircraft I have and what to do for the one I hope to build.

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Thorp T18
O-320-B3B (160 HP)
68x74 Sterba Propeller

"The joke in aviation is, 'If you want to make a million, you'd better start with £10m.' " -Bruce Dickinson