rdemy

Hi All,

I'm building a .25 Seamaster this winter, and I was thinking...

Wouldn't it be nice if when flying off the lake on a calm evening I had a way to make some smoke and do a few minutes of aerobatics...

So - I know absolutely nothing about smoke systems and I'm looking for all the advice I can get...

Remember this is a .25 size plane - so nothing overly heavy...

I thank you all in advance...

RD

MinnFlyer

My Feedback: (4)

Good luck! There are some systems out there that work strictly off the muffler pressure, but I have no experience with them. I am, however very familiar with the TME simple smoke pump. It is a good system, but will add considerable weight to your small plane.

Mendes

My Feedback: (1)

Unless you plan on using a small four stroke, forget about it. A .25 two stroke won't put out enough heat to make good smoke. The weight will also be a problem. Maybe you could put some lights on it instead, they look great late in the evening.

MHawker

My Feedback: (16)

What about that "smoke stick" I saw in the latest Tower catalog. It looks like a firecracker. It says it provides smoke for about 3 minutes.

Anyone use one of those?

Dauntae

I keep seeing posts about smoke on small engines and there not being enough heat, What would be the smallest you could go to get enough heat. The largest plane I have room for is a 40 size plane so would a 40-46 be enough.

Dauntae

Mendes

My Feedback: (1)

I have tried to get smoke on a .90 two stroke, it wasn't worth the effort. On the ground there is alot of smoke, but put it in the air and it looks like a slightly heavy exhaust trail. My next attempt is with a 1.8, we shall see.

That being said I have seen .52 four strokes pumping out tons of smoke, really good results. They had preheating coils wrapped around the outside of the muffler to get the smoke oil just a bit hotter before it actually gets injected into the muffler. I had a preheater on my .90 too but it didn't help much at all.

MHawker

My Feedback: (16)

Here's another thought... why not run a separate glow plug on the muffler? You could set it to light with a switch and it would burn the smoke oil.

Or would it cause some sort of spectacular explosion which at first would be cool until you saw you plane raining down in pieces.

Mike

Nuker

G'Day Rdemy, hope to see you at the field one of these days

Dubro has a smoke valve system that works off muffler pressure.

Instructions are at this location Cost is about $30-$40 Cdn for the components.

Both Alphonse and myself have installed this system in our bigger planes. Both are using a Saito .91 and we get ample smoke. What has been mentioned here is true in that a .25 2 stroke would probably not generate enough heat to "cook" the smoke oil enough. You would just end up spitting raw smoke oil into your lake where you fly.

I tried some preheating smoke manualy in my Saito .56 but didn't get as much smoke as the .91. Worth trying but I'm not sure if your .25 can pull it off.

If you want to see how it's setup, I'll have the Hog at the field on Saturday, stop on by and see.

Nuker

JohnW

My Feedback: (6)

I'm with nuker, you will have to preheat the smoke oil for your best chance of getting good smoke. However, I too am not sure if it is worth the effort. I've seen .40 size models with smoke... could hardly tell the diff between smoke on/off.

I have a YS140L wit a slimline smoke muffler with preheat chamber. It smokes, and you can tell the smoke is on, but it isn;t very dense. Now my DA100 on the other hand will smoke pretty good, but that's a big engine. Even better, a 3W240 will really pump out some serious smoke.

The key to good (dense) smoke is heat. A 2 cycle .25 will not deliver much heat. I don't think a extra glow plug in the exhaust will come anywhere close to adding enough heat... couldn't tell if that was a serious suggestion or a joke.

Good luck anyway.

Derrick-RCU

My Feedback: (1)

Hey Rdemy!

As a couple of others have mentioned the 2 stroke .25 just won't cut it. Even if it did the Seamaster II is a little on the small side and you would probably end up with a heavy plane from the extra gear smoke requires. You will definitely need a pumped system unless you want to make the pod behind the engine way too long!

rdemy

Oh well,

Sounds like from experience a .25 is just too small for the heat and weight...

Maybe I'll build it to the plans and just enjoy the beautiful flight's I'll get off the water...

Smoke will have to wait for a bigger plane.

Thanks all for the advice...

RD

MinnFlyer

My Feedback: (4)

I have a YS91 with a TME Simple Smoke Pump. It puts out the most amazing smoke you ever want to see. And there's no pre-heating.

It took me about a year of messing with it before I got it right, but believe me... I got it RIGHT!

There are a few things that you need to get good smoke. It's like when you want to make fire, you need heat, fuel, and oxygen. To make smoke, you just need heat and fuel, BUT... they need to be the right amount of BOTH!

First of all, I would be very hesitant to use a system that works off of muffler pressure. Even the TME system leaves something to be desired as there are times when it will stop working, (usually if it has been off for a minute or two) and I have to fly at idle for a while before it kicks in again. The B&B system is the best, but it only works on BIG engines.

So, you want a good pump to be sure that you are delivering a good, constant flow of oil to the muffler.

Next, you need heat. I don't pre-heat the oil, but I did wrap my muffler with a few layers of fiberglass cloth, wrapped that with aluminum tape, and then wrapped it with some thin copper wire to keep the tape from vibrating off.

My next consideration was fuel. I'm a cheapskate, so I looked into home-brews. But everyone had a different recipe, and most of them used things like fuel oil, diesel fuel, kerosene, etc. All these petroleum products will leave a residue on your plane that can attack the coverings adhesive. I didn't want that, plus several people mentioned how those mixtures stink up your car, and workshop, etc. So, after doing some extensive on-line searching, I found Ultrasmoke. Now there may be others, but this is what i use and it is fabulous! It's not a petroleum product, so it won't attack your covering, and you can use ANY kind of fuel line. It also doesn't stink, in fact I can't smell anything. it costs $10 a gallon from these guys:

http://www.aircapitalhobbies.com/

10 buck is a lot of money, but for the smoke I get, it's worth it!

The next (and one of the most important) thing is a flow control device. Too much oil is as bad as too little heat. There's a picture of the one I made. It's very simple to make. you just run the oil line through the hole and pinch it with the screw. With the engine running at full throttle, and the pump on, you just tighten the screw until the muffler is getting the right amount of oil. You'll know when that happens, because your neighborhood will disappear in a cloud of smoke.

One of these days, when I have nothing to do, I'm going to try it out on a 40 (and maybe even a 25) engine. I think it might work, although you would still have the weight problem to deal with.

MinnFlyer

My Feedback: (4)

And here's the smoke!

Nuker

G'Day MinnFlyer

actually the pressure system described in that link I posted seems to work quite fine. The main issue was with the pressure valve. The standard plastic one tends to get clogged and you lose tank pressure after a few flights. There is a metal version, more $$$ but it retains the pressure in the tank. A simple 6 oz tank gives about 5-6 minutes of smoke.

The smoke oil is controled via the dubro valve and that is connected to a dial knob on the transmitter so you can control the flow.

Pre-wrapping a copper coil around the muffler header is a must for this system.

Different things work for different folks I guess but I know the system works great and real inexpensive to boot. (I'm cheap too )

Nuker

GoNavy

My Feedback: (15)

Okay, what do we use for the preheater?

I find that 1/8 inch K & S copper tubing will work if you anneal it first. The trouble is it's hard to bend to small diameters, for example, around the exhaust tube of a 4 stroker, before the muffler.

The next smaller size, 3/32, is too constricted, and doesn't permit sufficient flow. Tough to construct headers or junctions for multiple 3/32 tubes.

Does anyone have a source for good preheater coil tube?

Does anyone drill holes in their 4 stroke mufflers and run in the smoke tubing?

Mendes

My Feedback: (1)

I have only made one preheater coil. I filled 1/8" brass tubing with salt and then bent it into a coil. It worked pretty well, the tubing didn't collapse at all. I have also heard of sticking braided cable into the tube before bending and then pulling it out after, I didn't have any cable when I made my coil so the salt had to do.

Nuker

Or you can pack with sandbox sand, fill with water and freeze. I ended up with the water method and it worked for me.

Bob aka Nuker

GoNavy

My Feedback: (15)

You know, I've been thinking about MHawakers idea,
post #7....wouldn't that be the reciprocating engine equivalent of afterburning?

MHawker

My Feedback: (16)

I've been thinking about my idea too. I've got a Cap 20L that is desparately in need of smoke.

I always thought that you could run tubing out through the wings and use a glow plug on the end to burn the oil.

hmmmmm. It would need a pretty strong pump. Maybe I could set up a test system first, off an airplane.

to be continued.........

Mike

MinnFlyer

My Feedback: (4)

MHawker, that better be one HOT F#@&ING glow plug! LOL

As to the preheater... Go to an Auto Parts store. They have 1/8" copper tubing that bends like a dream. I just picked some more up yesterday at a whopping 68 cents a foot. I have had NO trouble wrapping it aroung things as small as a pencil.

DENNIS C

My Feedback: (99)

hi guys i have a os 1.60 in a h9 540 with a jett muffler on it how can i hook it up with out changing muffler theres no pressure fitting on the jett i also have a cline on it also.
any info would be appericated

thanks dennis

MinnFlyer

My Feedback: (4)

All you need to do is to tap a hole for a pressure fitting right where the exhaust enters the muffler. Then you could use the TME smoke pump to pump the oil.

DENNIS C

My Feedback: (99)

thanks minnflyer i'll try that

Gbee

I've been using 2 "Don Harris" smoke mufflers and pumps on my Enya 1.20 4-strokes for over 10 years now. They work great. Anyone know if Don Harris (California) is still making smoke systems?

Swift071

My Feedback: (14)

Been working on this smoke thing for the past few months. Got it resolved using a .40 engine and got very impressive smoke. Kept the weight to an absolute minimum also.

The whole process can be seen here:
http://www.rcuniverse.com/showthread...r=2&forumid=58

The attached photo shows the results.

Bob J..