Fuel drain holes
for fire prevention

It is a good safety practice to drill a series of 1/16" holes in the bottom of the fuse (or wings) wherever fuel spills or leaks from fuel tanks might accumulate.
Additionally drill a few 1/16" holes in the bottom of the engine bypass duct. A wet spot under your model may alert you to a leaking tank or an overfill condition. More importantly, eliminating any puddling of fuel in the model will reduce the risk of a serious fire during a bungled start-up.

Slightly Wrinkled Tailpipes O.K.

Wrinkles, ripples, dimples, etc. in a stainless steel tailpipe are caused by slightly "rich" (too much fuel) during engine start-ups. This is a common occurrence, especially with electric auto start systems.
Deformations of 1/8" to 3/16" depth are not serious and will not measurably affect the engine or flight performance. The spot welds on a .007" stainless steel pipe are extremely strong and we have not seen any that have seperated as a result of a flaming start.
Ideally, the parameters of the E.C.U. program and operator technique should produce a lean-as-possible start sequence, thus eliminating the flaming start.
A serious tailpipe fire that causes significant deformation of the tailpipe will require that it be replaced. The incidence of flaming starts reduces considerably with operator experience.

Turbine Trouble Shooting

Most engine flame-outs are caused by a fault in the fuel system. Many of the faults can be traced to a minuscule air leak in a flexible tubing-to-metal tubing or Festo connector. Loose fitting fuel tank caps are another popular source of problems, especially the plastic variety.
Part of your engine start and run-up procedure should include a visual check of the translucent fuel line (BVM stocks 6mm clear tubing #T625) exiting the tank that feeds the fuel pump. There should be no bubbles at full power.
Position this tank in your model such that it is visible and check that the fuel level in it does not diminish during the full power run-up. This will indicate the security of the tubes and fittings in the next tank down the line.
Be sure that placing a hatch on the model does not put pressure on a fuel line that might induce a leak at a fitting.
Drill small holes in the bottom of the model that would allow drainage of fuel from a leaking tank, thus facilitating a check on the condition of the remaining, and possibly hidden tanks.

Removing a fuel line

The polyurethane fuel line really takes a set, especially over machined or soldered on nipples and is very hard to remove.
If the tank is completely void of fuel and fumes, heating the tubing will help. If not (most cases) use a sharp X-acto #11 blade and cut partially through the tubing to allow it to be peeled away. Caution: A linear score of the knife on a brass fitting could be a source of an air leak when the new tubing is applied.
We hope these tips will help you improve the reliability of your turbine powered model.

Turbine Fuel

On two occasions we have had problems using pump kerosene. Depending on the supplier, K-1 may not be consistent in quality, water content, contamination, etc.
Our experience has shown that if you can get Jet-A fuel at your local airport you should not have any problems that can be attributed to fuel. Be sure to accurately measure the oil content as your engine manufacturer recommends and avoid skin contact (with the turbine oil) and breathing the fumes.
Common sense handling is all that is required.

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