See update below
One of those things I always wanted in a plane since I was a kid was smoke. Nearly all of my R/C models have it. Just makes life a little more fun. This is going to be a great addition to Team RV at the shows. The basics are this; Pump as much oil into a hot exhaust and watch the smoke pour out.
First, I checked out several airshow performers and their smoke systems in detail. All had about 4-7 gal alum. tanks, high volume pumps with #6 lines into a solenoid valve, that split into #4 lines to the exhaust stack. Why the valve? To make the smoke go on and off instantaneously with out dribbling. Instant on and off.
First I picked up a Holley pump, model 12-208. 110gph at 14psi. Then I purchased a roll of aluminum .035 sheet, and some alum angle for the tank, various fittings, washers and so forth.
One key ingredient is the nozzle. Here is a #4 SS 90deg. fitting. I welded a washer that is bent to the curve of the exhaust. I also welded closed one end and drilled an 1/8" hole as a starter for the spray size. I made 2 of these.
I picked up a fuel cap assembly from ACS and began fabricating a tank to fit behind the passenger seat. Just alum angle, sheeting, rivets and proseal. I designed the sides on poster board, then cut out the sheets.
The pump is mounted to the tank, and the tank is easily removable with quick disconnects. Oh and removal is made easy with my tip up mod on my slider.
Mounted the solenoid to the firewall. Had to tap one end to 1/8" NPT.
The lines strap on to the exhausts with SS straps. You need to be able to clean out the holes in the spray nozzles about every 6 months or so or they get clogged up. SS flex lines will keep things from cracking from the heat and vibration here.
Here is the tank mounted inside the baggage compartment, behind the passenger seat
And here is Smoke On!
Update 10/7/2004
After using this for a while here are a couple things to consider:
1. On the SbyS models, I do think a homebuilt model tank like this can be made to fit and take up less room for more oil in the baggage as I have done. In the tandems, the off the shelf smoke tank is fine.
2. Make sure you can remove your exhaust fittings for cleaning. They do get clogged with carbon as does the line attaching to that fitting. Make sure you can run a drill bit through it for cleaning.
3. I am very glad I put the quick release fittings in to remove the tank. I take it in and out all the time.
4. Use a NOS fuel solenoid instead of the diesel fuel solenoid. It is an NOS fuel solenoid(used on nitrous systems) used in racing applications. It is lighter, cheaper and better than the solenoid I bought for the 6. Hollor if you want the part number