Smoke system smoke off

Ron Lee · #1 03-22-2011, 09:18 PM

I installed my Smoking Airplanes systems with two injectors last year. Once I started using it in the pattern for test purposes, another RV pilot was motivated to install his own homemade system. That produced smoke and his hangar buddy installed a similar system. So now there are three RVs on the airport with smoke.

Last week I saw both of them on an overhead approach using smoke and it looked fine. One appeared slightly less dense but still adequate. So they ask me for a smoke off to see who has the best smoke.

Last Saturday we did it. On the first pass another RV pilot stated that the person on the right (me) had better smoke. We made another pass for good measure. On the ground, I walked up to one of the other pilots and a ground-based observer. They stated that mine was inferior to their homemade systems. Of course you can be assured that an RV pilot (at least here) is one to kid, use disinformation, etc...so I just agreed.

Turns out that my system was significantly better in terms of smoke quantity and whiteness of smoke. The smoke quantity can be assumed to be tied to oil used. Theirs uses about 0.25 gallon/minute...mine 0.8-1.0 gallon/minute (not measured).

So based upon this, I suspect that the pump needs to output more than 0.25 gallons/minute.

As far as smoke color, I am using Conosol 260. Their oil was not specified but I would note that the Conosol 260 is the better of the two.

On this flight, my metering valve was set to 1.25 turns open. I will probably drop that to 0.75 turns to minimize oil consumption and hopefully still output adequate smoke.

When I talked about it to the second RV pilot, his comment was that "I smoked them."

Christopher Murphy · #2 03-22-2011, 09:55 PM

Its amazing how many variables there are in making good smoke. Below is a video of my RV-4 homemade smoke system using canopus 13. It used 3 gallons in 8 minutes.

http://www.youtube.com/watch?v=F3P5LMtBuwY

CM

WillyEyeBall · #3 03-23-2011, 05:55 AM

I added a fancy electronic box to my smoke system that dashes the smoke with negative Gs. I still have some problems with the nozzle clogging. Just goofing off with this video: http://www.youtube.com/watch?v=YVMRCWuzuf4
Will be competiting at the IAC competition this weekend at Keystone, FL, and will most likely be the only RV again.
Bill McLean
RV-4 Slider

Ron Lee · #4 03-23-2011, 08:45 AM

CM, you may be right about other variables. I can't judge their importance but the nozzle and nozzle placement may also be important. I am on dialup so may or may not be able to see your video.

At this time, I do suspect that smoke oil quantity pumped may be the largest factor.

If you produce comparable smoke to my last test using half the oil, then you are doing something very good and I prefer that oil consumption to what mine may be. Obviously, I need to check the flow rate.

Kahuna · #5 03-23-2011, 09:07 AM

Injector placement not a factor.
Rate is. Expect ~.5gpm in the typical 4cyl operation.

Christopher Murphy · #6 03-23-2011, 12:45 PM

More oil ,more smoke as long as you are converting it. Things like having 2 injectors in each of two pipes, or one injector in one collector pipe, make a difference. I am sure you have seen the "little puffer" smoke trail or the system that comes unported, or the one that leaves half the smoke oil on the belly. I have a 4 pipe system and each pipe has a small injector. The type of oil you use makes a big difference too, of course. The problem I have with my system is that occassionally the injectors will get plugged up.

CM

Ron Lee · #7 03-23-2011, 05:13 PM

I just got 0.7 gallons in one minute with the metering valve open 1.25 turns. Looks like I can lower that to 1.0 turns, reduce the oil consumption and still put out good smoke.

Kahuna · #8 03-23-2011, 06:20 PM

Quote:

Originally Posted by Ron Lee

I just got 0.7 gallons in one minute with the metering valve open 1.25 turns. Looks like I can lower that to 1.0 turns, reduce the oil consumption and still put out good smoke.

The number of turns is not relevant.
One mans 1 turn is another mans 2.
All installs of this same system have differnt turn outcomes.

Ron Lee · #9 03-24-2011, 05:31 AM

Kahuna, while you are correct, more info is better to quantify my flow rate. My recollection is that the Smoking Airplanes recommendation for initial testing is 1.25 turns. I suspect that if the systems are uniform with the same components, there should be reasonable uniformity.

More important is that it shows that for this system, your 0.5 GPM value may be close.

Kahuna · #10 03-24-2011, 06:03 AM

Quote:

Originally Posted by Ron Lee

Kahuna, while you are correct, more info is better to quantify my flow rate. My recollection is that the Smoking Airplanes recommendation for initial testing is 1.25 turns. I suspect that if the systems are uniform with the same components, there should be reasonable uniformity.

More important is that it shows that for this system, your 0.5 GPM value may be close.

For any ~180 hp engine (4cly or 12), that value will be close. Its not about your system, its about the amout of power and heat you are producing, and the oil flow you can deliver for the desired outcome. The valve turn tolerance is small. Meaning 1/8 turns make large flow rate changes. So it doesnt matter at all what yours is. The only thing that matters is the flow rate as measured by capturing the output. And Im afraid there is not reasonable uniformity in installs of the same system in the same planes for various reasons. I work with this issue regularly with a large # of different planes. Ive installed more of these than I care to admit.