Smoke Tank

I'm pulling the smoke tank out of the top wing to clean it up and reduce a little drag from the fittings, cap and plumbing running down the cabanes. Since I already had the Smoking Airplanes system, I talked to John about adding one of his tanks. After trying out a cardboard mock-up and talking a bit on the phone, I ordered up the parts need to finish it up. The tank and parts look great and are well made. Everything is very complete which makes the job pretty easy.

This tank is 3.5 gallons and was designed to fit under the fuel tank in a Pitts S-1. It fits there easily and with a little bit of wiggle room for fine tuning the location and fit. The biggest task will be adding the hard points for mounting the tank. Once I decide where I want them, it shouldn't be too hard to get them installed.

UPDATE - Tank mount finished. Plumbing and electrical next. This is mostly done, but I still need to install the remote fill tube and cap. I also will need to re-route the pump power once the switches and breakers are moved up to the new panel.

  • New location with external fill hose sitting in place. The fill hose will run behind the center of the panel with plenty of room. The flush filler cap will be installed in the top piece of aluminum sheeting.
  • This shows the normal fill cap, the fitting for the flop tube, the location of the external fill fitting (not installed) and the bracket that holds the adjustment valve. The rudder pedal heel trays will go on each side of the tank.
  • Here is the pump mounted on the forward side of the tank towards the firewall. The bottom fitting on the pump is the outlet and still needs to be connected to the adjustment valve. A short piece of hose can be seen on the top of the tank that goes to the valve. This is the general direction the new hose will be routed from the pump output.
  • Here you can see the red vent line and the hose that will run to the check valve and firewall fitting. The vent fitting is the only interference with the tank. The tank is sitting about 1/4" - 3/8" lower than normal. There are a few washers missing under the bottom straps that raise the tank up to the correct height for the sheet metal on top.
  • This picture shows the slight interference with the vent fitting. This will not be a problem when everything is installed correctly. You can also see the output hose and check valve that go to the firewall fitting.
  • This shows the simple bracket I made to hold the adjustment valve. John added an insert on that corner so that I could secure the valve and still be able to reach it in flight.
  • New tubes for the hardpoints on the front of the smoke tank. The cross tube will get a couple bushings that will allow the mount flange to bolt down.
  • This should take most of the bending loads off the floorboard tubes that all all in the same plane.
  • Both of the reinforcement tubes are well inside of where the foot trays and rudder pedals mounts.
  • The front tank bracket had to be notched slightly to fit between the new diagonal tubes.
  • The rear bracket location with the new tabs. I didn't want the bracket to ride on the bushings for the front torque tube bearing block.
  • This shows the new gussets and mounting tabs for the rear smoke tank bracket. The thin gusset material was tough to weld with a couple blow outs on the left side. The other side went better (practice) and the tabs were much easier with the thicker steel.
  • The tank, now located correctly on the new hard points. Just lacking the front bushings and the holes in the rear tabs and brackets.
  • Bottom detail of the hard points.
  • These small triangle gussets are for mounting a nut plate to hold down the front inside corner of the heel trays. Still need to bend up a couple trays.
  • Yes, the bolts don't line up with each other. Comes from center punching the holes underneath and then missing one with the drill. The hole that is off, is fine structurally, but I'm sure it will get pointed out regularly.
  • This is a good view of where the heel tray will go on the right side. I still need to add tabs for the rear outside corners of the trays.