Belly Pods and CO levels

[Dan L]

How did you add an extension? Pictures?

680EDD07-614B-4AB0-A6A5-D3A97785C5F4.jpg

Vetterman exhaust system. Clint made the extensions.

[N867SP]

So I hand fit the pod to the belly of my aircraft to remove any fitment issues. Then proceeded to tape up any gaps on the belly of the plane and test fly while taking readings. No difference. Readings only change when you change the pressure in the cabin. Go negative and the CO rises 300-400PPM at the openings at the seat base. Go positive and you can drop readings down to 10-40PPM. Remove pod and readings are 0PPM.

Something is going on with the way the air is moving in front of the pod and driving the exhaust into the belly of the aircraft. I taped all openings, gaps, seams, joints, etc.

With factory exhaust being tapered and flares at the end, extensions like Dan’s are not as easy.

Will spend some more time this winter working they solutions.

Pete


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[Dan L]

Readings in the hundreds is dangerously high. In my recent flying mine are now sub-ten.

I'm wondering what openings in the seat base you’re referring too? Where the battery cables penetrate?

Could the Heat valve box be the source? They’re not sealed real tight and I know from tracking oil stains my pod causes oil to flow into the direction of flight in that general area. The pod does strange things to the flow. A friend put a pod on his Citabria this spring and had a lot of weird airflow issues too, mostly with cylinder cooling.

It looks like your blue tape should have covered the openings Bob mentioned where the gear attaches. Those are source of flow too.

[hawgdrvr]

So I hand fit the pod to the belly of my aircraft to remove any fitment issues. Then proceeded to tape up any gaps on the belly of the plane and test fly while taking readings. No difference. Readings only change when you change the pressure in the cabin. Go negative and the CO rises 300-400PPM at the openings at the seat base. Go positive and you can drop readings down to 10-40PPM. Remove pod and readings are 0PPM.

Something is going on with the way the air is moving in front of the pod and driving the exhaust into the belly of the aircraft. I taped all openings, gaps, seams, joints, etc.

With factory exhaust being tapered and flares at the end, extensions like Dan’s are not as easy.

Will spend some more time this winter working they solutions.

Pete


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Great info! Giving me second thoughts on buying a pod. What are you using for a CO detector as I need to get one.

[N867SP]

Readings in the hundreds is dangerously high. In my recent flying mine are now sub-ten.

I'm wondering what openings in the seat base you’re referring too? Where the battery cables penetrate?

Could the Heat valve box be the source? They’re not sealed real tight and I know from tracking oil stains my pod causes oil to flow into the direction of flight in that general area. The pod does strange things to the flow. A friend put a pod on his Citabria this spring and had a lot of weird airflow issues too, mostly with cylinder cooling.

It looks like your blue tape should have covered the openings Bob mentioned where the gear attaches. Those are source of flow too.

Yeah, the blue tape did cover the openings at the cabane vee to fuselage.

The openings would be where to torque tube passes thru seat base at front and rear. That’s where I had the highest readings. Other openings are grommeted and sealed pretty tight.

If you keep the sky light vents pointed forward and cockpit pressurized numbers are low. If you open cabin heat and pressurize cabin numbers are low. If you turn skylight vents around to vent cabin into negative, numbers climb. As you lean the mixture numbers drop. Straight and level numbers. We’re higher than climb or decent numbers.

Just did 15hrs to and from WAD and we’re always able to keep numbers <50PPM but took some work in proper venting, luckily we had mild temps.


Pete Meyer
Severna Park, MD
CCK-1865-0078
N9PW

[N867SP]

Great info! Giving me second thoughts on buying a pod. What are you using for a CO detector as I need to get one.

Ive been using the Fluke co-220, it’s what I carried on my service truck doing HVAC service.


https://www.grainger.com/product/4TP...9F1R6:20501231


Pete Meyer
Severna Park, MD
CCK-1865-0078
N9PW

[turbopilot]

Ive been using the Fluke co-220, it’s what I carried on my service truck doing HVAC service.


https://www.grainger.com/product/4TP...9F1R6:20501231


Pete Meyer
Severna Park, MD
CCK-1865-0078
N9PW

That looks like a professional device. For now I am using my Sentry working through ForeFlight. Sentry will alarm (with yellow light on device and popup on IOS ForeFlight) when CO goes above 30 ppm. It will then alarm with red light, audible alarm and IOS notification when CO ppm is above 50.

The Sentry will not give direct PPM readings just threshold alarms. For grins I just ordered a $24 CO meter from Amazon with direct digital read out.

With or without a belly pod, CO in the cockpit is a big deal. As I posted earlier just leaving a belly access plate off my CC raised CO above 50 ppm with a Sentry alarm. I suppose the same thing could happen if a stone put a hole in the belly fabric in the right place. One way or another, with or without a belly pod every airplane should have a CO monitor.

[N867SP]

That looks like a professional device. For now I am using my Sentry working through ForeFlight. Sentry will alarm (with yellow light on device and popup on IOS ForeFlight) when CO goes above 30 ppm. It will then alarm with red light, audible alarm and IOS notification when CO ppm is above 50.

The Sentry will not give direct PPM readings just threshold alarms. For grins I just ordered a $24 CO meter from Amazon with direct digital read out.

With or without a belly pod, CO in the cockpit is a big deal. As I posted earlier just leaving a belly access plate off my CC raised CO above 50 ppm with a Sentry alarm. I suppose the same thing could happen if a stone put a hole in the belly fabric in the right place. One way or another, with or without a belly pod every airplane should have a CO monitor.

Couldn’t agree more. Placement of the device is important too. The levels of CO vary depending on the source and entry point. CO does not sink or rise but mixes. I take readings at waist level so I have a margin of safety from low entry point of CO to mouth and nose. Keep in mind that if you fly with pets as they tend to lay down and sleep in flight.


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[Dan L]

This is what I’m using.

F756209D-FDA1-4DA4-BA21-ED0E4EA5612A.jpg

85F17773-71FA-429D-A4E0-899068B99875.jpg

[hawgdrvr]

This was in my aircraft spruce email today. Any opinions? I like that it's something always monitoring and can alert vs. me having to take readings or just use a cheap card attached to the dash that may not catch my attention when there is a problem.

https://www.aircraftspruce.com/catal...es/co_w500.php