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  #1  
Old 05-26-2014, 09:19 PM
gear1 gear1 is offline
 
Join Date: Sep 2008
Location: Pagosa Springs CO
Posts: 257
Default Another home-made smoke system

A partially finished smoke tank for the front baggage well came with my RV8 when I purchased it, so I decided to make my own system by completing and painting the tank, installing a submerged pump in the tank, and doing all of the plumbing with stainless braided hose. The system weighs less than 5 pounds excluding the firewall forward plumbing. The tank, about to be installed is shown below:

[IMG][/IMG]

The pump system consists of an automotive in-tank pump from TRE Performance (thanks to the idea from Alan of Anti-Slat), a home-made pressure regulator, and a flow regulation valve obtained from McMaster-Carr and Marvin Helmsley’s injector nozzles. Standard aircraft hardware was used throughout.

[IMG][/IMG]

The pressure regulator was made from a bulkhead run “T”, with the side leg bored for a ¼” ball and a fine spring for pressure control. Bleed holes were drilled at the relief point. The pressure regulates to 32PSI.

[IMG][/IMG]

The tank fits into the drop area of the forward baggage compartment.

[IMG][/IMG]

The system is controlled by a relay, which is grounded through a switch on the throttle. Power is supplied through a 15 amp circuit breaker and a smoke "arm" switch on the instrument panel.

[IMG][/IMG]

This was the first test of the system

[IMG][/IMG]

Since the firewall forward line to the left side of the engine is longer than the line to the right side, a flow restrictor orifice was inserted in the bulkhead “T” outlet serving the right side of the engine. The outlet was drilled out to 3/16” to a depth of 1/4" and a number of restrictors were fabricated for test. We ended up using a restrictor with a 1/16” hole to get balanced flow to both nozzles.

So far, great smoke at 1/3 gallon per minute of smoke oil!
__________________
Craig Taylor
RV8 flying
2021 VAF dues paid with thanks
Navy A7E Vietnam era
Ret. Corporate Pilot: Gulfstream, IA Jet, Jetstar, Falcon 10, 20, 50, HS125

Last edited by gear1 : 05-26-2014 at 09:30 PM. Reason: Photos would not imbed
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  #2  
Old 05-27-2014, 12:00 AM
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Kahuna Kahuna is offline
 
Join Date: Dec 2004
Location: Gold Hill, NC25
Posts: 2,419
Default

Neat system. Especially the submerged pump. I think you will find the in tank pump will have difficulty making the flow rate you need for good smoke at speed. Your flow rate needs to be at least 1/2 gal/min. It takes a pretty big pump to do that with oil. Let us know how it compares with your other smoking friends in the sky.
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  #3  
Old 05-27-2014, 11:53 AM
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Low Pass Low Pass is offline
 
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Location: Houston
Posts: 2,121
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I think you're onto something with that submersible pump! Can you tell us the rated flow and pressure?
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  #4  
Old 05-27-2014, 01:59 PM
gear1 gear1 is offline
 
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Location: Pagosa Springs CO
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Default Submersible pump

The pump is from TRE performance (www.treperformance.com/fuel pumps $70.) and is rated at 255 liters/hour (67.5 Gph) at free flow and 210 L/hr (55.65 Gph) at 35 psi. Typical usage as pointed out by Kahuna is .5 G/min or 30 Gph. The pump is a positive displacement type, and is capable of 140 PSI at 5 Gph. Therefore a pressure regulator is required. At 35psi the pump pulls 10 amps, with the draw proportional to pressure. It might be possible to use a smaller version of this pump to cut power consumption

I am beginning to wonder if this type of pump could replace the Airflow Performance that is so common in RV aircraft.
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Craig Taylor
RV8 flying
2021 VAF dues paid with thanks
Navy A7E Vietnam era
Ret. Corporate Pilot: Gulfstream, IA Jet, Jetstar, Falcon 10, 20, 50, HS125
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  #5  
Old 05-28-2014, 09:21 AM
Tomcat RV4 Tomcat RV4 is offline
 
Join Date: Nov 2007
Location: Jacksonville,Fl. 32246
Posts: 281
Default Another home made smoke system

Don't know how many of you are aware, but ALL of todays (and last 10 yrs) autos use those type of in tank pumps for supplying fuel at high pressure at their fuel injection....I have considered using on fuel tanks in RV4 as will have fuel injected engine. Pumps are available with various pressures and wide range of prices.They also have a very great filter attached that in auto use lasts thousands of miles unless fed poor dirty fuel.....Tom
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  #6  
Old 05-28-2014, 09:31 AM
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Kahuna Kahuna is offline
 
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Location: Gold Hill, NC25
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Quote:
Originally Posted by gear1 View Post
The pump is from TRE performance (www.treperformance.com/fuel pumps $70.) and is rated at 255 liters/hour (67.5 Gph) at free flow and 210 L/hr (55.65 Gph) at 35 psi. Typical usage as pointed out by Kahuna is .5 G/min or 30 Gph. The pump is a positive displacement type, and is capable of 140 PSI at 5 Gph. Therefore a pressure regulator is required. At 35psi the pump pulls 10 amps, with the draw proportional to pressure. It might be possible to use a smaller version of this pump to cut power consumption

I am beginning to wonder if this type of pump could replace the Airflow Performance that is so common in RV aircraft.
Craig,
Have you tested the flow rate of the oil out of the pump? Looking at your picture (always hard to tell), Id say your rate is ~half of what it needs to be. Could have been just you testing. But Im interested in the rate out of the injectors. A catch can and watch is all that is required.
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  #7  
Old 05-28-2014, 05:11 PM
gear1 gear1 is offline
 
Join Date: Sep 2008
Location: Pagosa Springs CO
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Default Flow Rate Testing

Kahuna,

Good question. Yes we did test the flow rate through the injectors as you describe. At about 1 turn on the McMaster Carr needle valve we were getting more than 1 GPM flow from the exhaust pipes. The photo was taken at 1/2 turn of the needle valve, which yielded exactly .5 GPM flow from the pipes. The test RPM was 1800, and resulted in the belly of the aircraft being covered with oil. I think the limited smoke problem was the result of not enough exhaust flow relative to the smoke oil flow. We dialed it back to about 1/3 GPM for flight test, and the belly has remained oil-free. I will get some photos tomorrow showing the smoke. We did a 5-ship flyover over the Veterans Home in Monte Vista CO on Memorial Day, and my wingman and ground observers reported good smoke with a long hang time.

I will also try a ground test with the valve completely open to see what the maximum flow rate could be. Hopefully I can do this tomorrow, too.

Thanks, Kahuna for insisting that we document this experiment. One question for you, Kahuna: what would you use a substitute for good smoke oil? I am nearly out of the initial 5 gallon supply, and more is on order, but a couple of gallons of something will be required for the maximum flow test.

Thanks, everyone for your inputs. Nearly all of the ideas for my system came from the capable folks on Van's Airforce!
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Craig Taylor
RV8 flying
2021 VAF dues paid with thanks
Navy A7E Vietnam era
Ret. Corporate Pilot: Gulfstream, IA Jet, Jetstar, Falcon 10, 20, 50, HS125
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  #8  
Old 05-28-2014, 07:05 PM
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Kahuna Kahuna is offline
 
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Location: Gold Hill, NC25
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Default

Excellent report. You have proved me wrong on that pumps ability to flow the rate. And its doing it at twice the necessary rate. Well done. Pumps and related junk take up valuable baggage space. Love your solution.

As for an acceptable solution, a couple of us have used diesel in a pinch. It does stink and does not smoke as well, but its good for tossing overboard for testing, and is readily available.

Great project and thanks for sharing.
PS, now about its ability to smoke inverted A flop pump?
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  #9  
Old 05-28-2014, 09:29 PM
BillSchlatterer BillSchlatterer is offline
 
Join Date: Jan 2005
Location: Arkansas
Posts: 601
Default Source for Smoke Oil

Quote:
Originally Posted by gear1 View Post

One question for you, Kahuna: what would you use a substitute for good smoke oil? I am nearly out of the initial 5 gallon supply, and more is on order, but a couple of gallons of something will be required for the maximum flow test.

!
I did a little research and found that most smoke oil is a Parrafinic Type 1 oil which is usually White Mineral Oil. Oddly enough it is rated for contact with food and smokes well because of the high paraffin content. Call a local wholesale oil distributor and ask for Agricultural Smoke Oil. I am told they use it to check winds when dusting. I have been getting it in 5 gal buckets but you can get it in 55 gal as well. You will find it has a yellow tint but practically clear and works well in wick style lanterns as well. It burns very clean with a little clear residue and what is there comes off very easy with "Scubbing Bubbles". It may not be as good as the high dollar stuff but it looks the same coming out of an exhaust pipe.

Depending on the distributor, it will cost about $60-$70 a 5 gal bucket FOB. It doesn't stink and works well. I would guess it at about 10 weight. You can't light it with a match but put a paper towel in it and it will burn nicely. Send me a PM if you want the specs on it. Hard for me to justify diesel when this is readily available and seems a lot safer and cleaner than something like diesel or transmission fluid.

You can also order it from your local Bumper to Bumper Autoparts store in Ark, La, Mo, Ms, East Ok, Tn, and East Tx. Part number is 12805 LUB.

Hope that helps!
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Last edited by BillSchlatterer : 05-28-2014 at 09:41 PM.
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  #10  
Old 05-29-2014, 07:46 AM
gear1 gear1 is offline
 
Join Date: Sep 2008
Location: Pagosa Springs CO
Posts: 257
Default Smoke oil

Thanks, Bill and Kahuna
This is exactly what I needed!:
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Craig Taylor
RV8 flying
2021 VAF dues paid with thanks
Navy A7E Vietnam era
Ret. Corporate Pilot: Gulfstream, IA Jet, Jetstar, Falcon 10, 20, 50, HS125

Last edited by gear1 : 05-29-2014 at 07:49 AM. Reason: Add thanks to Kahuna
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