smoke oil

Talked with a bloke that does a bit of this with RC gear, and does a few
"shows". He uses diesel fuel and about 20% white oil like you would use on
your rose garden. The white oil makes the smoke much whiter than straight
diesel, but cannot be mixed to thick so it won't flow. He preheats the oil
mix in copper pipe that goes past the head before it goes into the exhaust
pipe at the hot end near the head.

This is on glow plug and whipper snipper two strokes, but may help.

Peter

Bushy wrote:

The white oil makes the smoke much

I actually wrote an article on smoke oil
which was published by IAC's Sport Aerobatics
magazine about a year ago.

Here's an online text version:

http://www.pittspecials.com/articles...il_article.txt

--
ATP http://www.pittspecials.com/images/oz_inv.jpg

Great work. Thanks.

How much volume are you trying to push through there. We are up to almost
1gal/minute and getting fair smoke, but with the rotor downwash, it defuses
too quickly. In forward speed, the smoke is OK, but below 40kts, it gets
beat up quickly. Looks more like we are on fire than that we are leaving
smoke trails!

"Andrew Boyd" wrote in message
om...
Bushy wrote:

The white oil makes the smoke much

I actually wrote an article on smoke oil
which was published by IAC's Sport Aerobatics
magazine about a year ago.

Here's an online text version:

http://www.pittspecials.com/articles...il_article.txt

--
ATP http://www.pittspecials.com/images/oz_inv.jpg

"nametab" wrote:

How much volume are you trying to push through there. We are up to almost
1gal/minute and getting fair smoke, but with the rotor downwash, it defuses

The volumn of smoke oil you can pump through depends upon the
volume of your exhaust gas. A bigger engine, or running at a
higher RPM (or both) will usefully allow a higher smoke oil
volume.

For a big piston engine (eg 540 cubic inches) 1 gal/min should
give very good smoke, with the right smoke oil. Check the
flashpoint of your oil - betcha it's up around 400F. You'll
get better smoke with a (CoC) flashpoint of 250F.

As far as dealing with rotor downwash, you're on your own! I
don't know nothin' 'bout fling wing :-)

--
ATP http://www.pittspecials.com/images/oz_down.jpg

It's a turbine, so can't change the RPM! The measured temperature at the
injection point is at least 450C and up to 600C, so I wonder what the flash
point difference between 250f and 400F would have. Will check the flash
point of the stuff I'm using. I'm also using quite a lot of diesel to make
it flow; about 1/3. It does make cool smoke when the flow goes through the
Fenestron... but in a hover it just gets defused by the rotor wash.

"Andrew Boyd" wrote in message
m...
"nametab" wrote:

How much volume are you trying to push through there. We are up to
almost
1gal/minute and getting fair smoke, but with the rotor downwash, it
defuses

The volumn of smoke oil you can pump through depends upon the
volume of your exhaust gas. A bigger engine, or running at a
higher RPM (or both) will usefully allow a higher smoke oil
volume.

For a big piston engine (eg 540 cubic inches) 1 gal/min should
give very good smoke, with the right smoke oil. Check the
flashpoint of your oil - betcha it's up around 400F. You'll
get better smoke with a (CoC) flashpoint of 250F.

As far as dealing with rotor downwash, you're on your own! I
don't know nothin' 'bout fling wing :-)

--
ATP http://www.pittspecials.com/images/oz_down.jpg

It's a turbine, so can't change the RPM! The measured temperature at the
injection point is at least 450C and up to 600C...

Temperature matters. For instance, the USAF and USN jet teams inject at the
aftmost plane of the exhaust nozzle. That's fine as long as the throttles are
at MIL or less, but if they go into burner, the smoke disappears.

BTW, the Thunderbirds use about one drum of smoke oil (1010) per jet per
half-hour performance.

I contacted NOCO about the oil you mentioned in your article and they
stated that they no longer produce that oil. Needless to say I was
not happy.

Gus Rasch
Pitts S1S
N21JF



(Andrew Boyd) wrote in message . com...
Bushy wrote:

The white oil makes the smoke much

I actually wrote an article on smoke oil
which was published by IAC's Sport Aerobatics
magazine about a year ago.

Here's an online text version:

http://www.pittspecials.com/articles...il_article.txt

(Gus Rasch) wrote:

I contacted NOCO about the oil you mentioned in your article and they
stated that they no longer produce that oil.

Someone emailed me and said that NOCO wanted a minimum
10 barrel order, which I intend to place in the near
future - I've got three thirsty S-2B's to keep smoking
and we can go through a barrel in one weekend - that's
only 3 flights :-)

--
ATP http://www.pittspecials.com/images/da2.jpg

What type of volume would you expect to use on a small piston engine.. say an
80 CID Harley Evo v-twin?

Harry

wrote:

What type of volume would you expect to use on a small piston engine
say an 80 CID Harley Evo v-twin?

Let's make some horrific assumptions about RPM
and volumetric efficiency. We know that 1 gallon
per minute works for 540 cubic inches. Therefore,
for a 80 cubic inch engine under the same conditions:

(80 cubes / 540 cubes) x 1 gal/min = 0.15 gal/min

Note that we run our direct-drive aircraft engines
at less than 3000 rpm, otherwise our prop tips go
supersonic, and that's a whole different world.

I suspect your RPM might be a bit higher than ours,
lets say 6,000 rpm or twice ours, so that would double
(maybe) your exhaust gas flow, therefore you might try
0.30 gal/min flow, which is a bit aggressive, but I
suspect might work quite well.

When running smoke, you need to have the throttle
open, making power and RPM. Smoke doesn't work
well at low power settings - no exhaust gas flow,
and the stacks are cold.

Hope this helps - I can guarantee it's worth what you
paid me for it! :-)

--
aboyd