F 16 - Fighting Falcon

Maßstab 1:8

Turbine - Installation

In the following essay, Michael Lieser describes the installation of a gas turbine into a F-16 from Gleichauf, which has similar dimensions as our F-16. He uses a FunSonic FS60 turbine with 12 pound thrust.

Installation space

Before starting work you should have a look at your model’s installation space. Generally you can say that where an ducted fan fits in there will also be space for a turbine in the size of a FS60.

In the following example, you can quickly see that concerning space there will be no problems.

Image1: Comparison of a .90 ducted fan with the FS60 turbine

Image2: FS60 turbine mounted directly into the rear of the F16

Thrust tube

Generally, a thrusttube has only disadvantages. It is heavy, it reduces power output, it costs quite a bit and additionally, it advoids the special jet noise.

In some cases, however, you need to install a „thrusttube“. Because of the turbine’s weight it cannot be installed at the rear end but has to be placed near the CG.

If you can omit the „thrusttube“, you will realize a weight reduction of ca. 200-300g. Furthermore, you will save 80-120$. This is only feasible if the turbine is small and does not weigh too much to be installed at the rear end.

Weight ratio and leverage in a fuelled F16 show a thrust/weight ratio of 1:1 and even better.

Bigger turbines, such as the class of 18lbs, are simply too large for backfitting a .90 ducted fan model. They have to be installed in the CG. Additionally, you have to place ca. 2-2.5 litre kerosine, and then things are getting tight.

Model data F16

The following weight data refers to a normally built ROJets F16 with 2C painted, pneumatic gear and built-in turbine and tank frame/former.

Weight
System weight for the turbine	1.300 with FS60-turbine, pump, accu, turbine electronics, fuel tank (empty) and houses
Model	4550 g with 5 normal servos, receiver accu, receiver and landing gear
Fuel	1350 g with 1,5liter
Total fleight weight (tank full)	7000 g *

*weight ratios are only valid if the especially small and light FS60 turbine by FunSonic is used.

Turbine data FS60

Lenght	240 mm (200mm until nozzel)
Diameter	83 mm
Weight	720g + 28g for clamp
Accu	236 g
Pump	68 g
ECU	136 g
System weight	1.178 g without fuel tank and tubing

Thrust (max)	60 N at 165.000 U/min
Thrust (min)	2,5N
Fuel consumtion	160 g/min
Fuel	Kerosin with 5% turbine oel

Installation of turbine frames/formers

The turbine frame/former should be as big as 4mm minimum. Two simple aluminum elbows connect the turbine clamping piece with the frame/former.

With 4 screws are the aluminum elbows fastened to the frame/former. If required you dismantle these 4 screws and the turbine can simply be removed backwards from the body.

The frame/former itself is resinated 150mm from the back into the rear.

By doing this, you can easily adjust the thrust axis.

Image3: Can a turbine frame/former be more simple

Fuel tank installation

Take a 1.5 liter coke bottle as a fuel tank that is held in the front and in the back of the body by 2 frames/formers.

This volume lasts for flight-times of 7-10 min.

The backward frame/former has an additional bore-hole in order to admit the pump and is simply screwed on the „old“ fan former/frame

Image4: And a tank frame can’t be simpler either

Fuel line installation

The main difference between the impeller-model and the jet-model is that you may not use silicone tubes.

In combination with turbine fuel silicone will dissolve and will clog the model’s lines.

Please always use the standard commercially available pneumatic tubes.

For safety reasons, a Hopper-tank and a large fuel filter should be installed as well.

Gas tank installation

You can install the gas tank at any place you chose. On their way to the turbine fuel lines and gas lines should always be neatly fixed and should be secured from slipping.

Installation of electronics

For safety reasons, you should install the ECU (turbine electronics) as far as possible from the receiver and the model’s antenna.

In order to increase receiving performance a probe antenna has been attached to the body.

Inlet air filter

For safety reasons, you should install a inlet air filter in front of the turbine’s inlet. This measure protects particularly jet-models with underlying air intake and it increases their durability. You can

First turbine running

It is quite impossible that the model might catch fire while operating.

For safety reasons, you should always keep a fire extinguisher ready.

First flight

Refuel and off you go!

Generally, I recommend an adequate 50% thrust during the flight. You need 100% only for the start or for flying particular vertical figures.

Full throttle

Take off after ca. 20m

Have Fun!

Conclusion

Turbine installation incorporates only a small amount of work.

Autor: Michael Lieser

with kind permission by FunSonic Turbines