Smoke in cockpit from smoke system..

Ok, the smokmesystem works really well and even fills the cockpit with lots of smoke!!! I guess that it's time to seal every nook and cranny coming into the fuselage......aileron pusrod booties, space around the spar, pitot line holes, cap the rear vent or get a better one, etc.

The smoke comes up around the rear stick area so it must be travelling from the above mentioned areas and under the floor. Funny that I never smell any exhaust ! Has anyone else with a smoke system noticed this problem and what were there solutions?

Cheers!

Same thing here.

Reminded me of the Cheech and Chong era.

Wanted to take pic of it but haven't yet.

Open up the vents will help alot.

Don't know where it is coming from but think it is coming
in the back with the amount of smoke oil on the floor
behind the back wall in my 7.

Would carbon monoxide come in via the same path even with the smoke system off? I've never flown an airplane with a smoke system, but I'd think the answer would be YES.

Yep, it sure would! I knew that there was a little bit of air getting in, but until I turned the smoke on, I would have never guessed how much!

longranger said:

Would carbon monoxide come in via the same path even with the smoke system off? I've never flown an airplane with a smoke system, but I'd think the answer would be YES.

Click to expand...

The answer is no.... Its called coefficient of thermal expansion related to volumetric thermal expansivity.

I never had that problem with my smoke system.
Could it be that the rear air vent is open and it is coming in the under wing NACA vent?

Rear vent was closed but the one in the back is the cheap black one included in the kit. I am going to tape over the NACA vent on the lower right wing and test. If it makes a difference, I will have to order another nice eyeball vent like the ones that I put up front

Errr, yes you do get a potential for CO in the cockpit.

When you are at flaps full, approach speed, exhaust fumes enter the cockpit - I guess through the flap drive holes which are normally blanked in cruise flight.

Kahuna said:

The answer is no.... Its called coefficient of thermal expansion related to volumetric thermal expansivity.

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Wait, I thought that's what happens when the Ghostbusters crossed the streams!

Concur though...the primary CO threat is from firewall leaks, methinks.

For cockpit smoke infusion (which I get too) I've been told that the flap rod holes are the major culprit (unsubstantiated, so that's a FWIW statement). Since smoke does not envelope the canopy (normally), it seems its coming in from somewhere below, and I always notice it moving forward in my -6, so those openings may very well be the point of entry (even in cruise, there may be leakage). I need to bring an observer to see if they can see the path and/or entry point. Mike's point about flaps down, approach speed CO entry may be related...though I haven't experienced any exhaust smell in the pattern (but I know, CO is odorless!).

Just thinking about it, the tailspring gets pretty oily from smoke, and perhaps its even getting in way back there, where the spring enters the fuse, or via the bottom rudder hinge gap, then meandering all the way forward.

Kahuna, have any Team RV members solved the issue? Perhaps its just a part of the smokin' game we deal with, and open the vents to keep the air moving.

Cheers,
Bob

I respectfully disagree with the comment about Carbon Monoxide NOT getting in the cockpit the same way. It does, actually, and especially on climb out. For those who happen to have one of the CO Guardians and have it wired via the serial port to one of the supported devices (G-430, AFS-4500, etc), it will actually read out the ppm. On climbout in the 10 and the 7 I have seen the numbers reach 20-23, and as soon as I get into cruise flight it immediately goes to zero. I always make certain I have the vent cracked a little, but in all of the years of flying without the CO Guardian never knew this was happening.

Vic

Vic,

That is interesting (and good) info. What type of monitor do you have, and where do you mount it? Also, what types of components can they be connected to (I don't have a USB port in my panel gear, but would be interested in an alternate scheme...have been looking at some small portable CO units, but your set up sounds pretty sensitive). Finally, what ppm become worriesome? It's be interesting to see what the meter reads when smoke is getting in (I've seen that happen slow and fast, maneuvering and straight and level). Thanks again...good info.

Cheers,
Bob

As a data point. I also have an electronic CO monitor, no digitial read out, and with the cockpit filled with smoke oil IMC, it has never gone off. I use this device on test flying planes to make sure I know what the CO is doing.

There are other conditions where it will go off, tail slides & spins as an example. Reminds me it is still working.

Well, I taped over the NACA vent on the right wing as I thought that it may be a contributor to the cockpit smoke ingestion. It really did not make much of a difference.

The smoke, from what I can see, comes up around the rear stick. Just waiting on my aileron pushrod tube booties before I haul the floor and start the sealing process.

After laying on my back for awhile staring at the bottom of the fuse, I am beginning to believe that the majority of smoke is probably coming in around the flap pushrods. I cannot think of a way to seal those suckers...any thoughts??

Experienced it. Not solved it.

rvmills said:

Wait, I thought that's what happens when the Ghostbusters crossed the streams!

<<<SNIP>>>

Kahuna, have any Team RV members solved the issue? Perhaps its just a part of the smokin' game we deal with, and open the vents to keep the air moving.

Cheers,
Bob

Click to expand...

During one of our (Team RV) Airshow performances, I experienced smoke in the cockpit.
1. I fly an RV6
2. The smoke seemed to come from **AFT**
3. It was relatively cold outside so my vents were closed but I quickly exchanged warm and cozy for better visibility!!
4. That was the only time it happened
5. And oh, we were not straight and level!

So ... I suspect there is a slight low pressure in the cabin and that the smoke was being sucked in (hole for flap extension arm?) as it "billowed" outward.

If I would have had cabin heat on, I suspect there would have been a slight positive pressure and it would not have happened. With the vents blowing just cool air it has not happened.

James

On my rocket I covered up the lightening holes in the aft bulkhead just before the tail, and put a boot for the elevator pushrod just like the ones commonly used for sealing the aileron pushrods. I did this for two reasons: 1. keep smoke from rolling in and 2. to eliminate cold drafts which come from the tail.

In a friends T-6 any time the smoke is used it just comes rolling into the cockpit like a fog bank. My wife doesn't like it when I fly in the T-6 because I come home smelling like "old airplane"

"If I would have had cabin heat on, I suspect there would have been a slight positive pressure and it would not have happened. With the vents blowing just cool air it has not happened'


In the last test, both panel vents were open and the cabin heat was on. The rear vent NACA scoop on the inboard right wing was taped over .

Maybe I need more positive pressure, but that would entail building another fuse and prosealing all joints and installing a compressor on the engine....hey Vans, how about a pressurized RV ?

I have the CO Guardian (model 352c I think). It has a serial out line, and it is wired into the serial port 4 on my second AFS screen (4500). I have it mounted right under the panel above my feet in the RV-10. My thoughts were that it would be in a good place there to pick up any CO from the heat.

Vic

smoke

Ever since I installed my smoke system about a year ago, I have noticed the same thing. Smoke fills the cockpit, especially if I keep the smoke on for more than about 20 or 30 seconds. It was disconcerting the first couple of times, especially when it begins at the top of the loop. Now it doesn't bother me as much; I just let off the button at some point before I can no longer see out of the airplane.