Tampereen suihkuvoimatekniikan klubi

Tampere Jet Propulsion Laboratory

We have also managed to take some videoclips from our videotapes. We must apologize for the poor image quality. The video camera that we used was malfunctioning and so some of the images are too blue. The audio is only on one channel so please turn your player to mono playback. Some clips have the audio on very low volume level and some on normal level, so you must adjust your audio card accordingly. If you don't have a mpeg viewer yet you can download one from here.

The increase from 120 N to 200 N was achieved by changing a larger diameter compressor wheel to the turbo and adjusting the end cone to a smaller diameter. The compressor housing required some machining in a lathe to be able to house the bigger wheel. The optimal opening of the end cone was found experimemtally by changing the size with a moveable nozzle and measuring the thrust several times with different nozzle positions. When we found the right size a new cone was made to that size. This videoclip (3.6MB/19s) shows the measurement setup. There is a pneumatic cylinder connected to a pressure gauge which shows how much force is subjected to the cylinder. The jet bike is on a plate that has sliding ball bearing tracks under it so the bike can easilly move. The bike is tied on the cylinder and the cylinder is tied to a steel lamp post. At the beginning of the clip there is the startup sequence and at the middle you can see the gauge, the cylinder and the lamp post hose at lower left corner. You can hear how silent our new starter is. The starter consists still of the leaf blower but we have changed the 2-stroke engine to a electric motor that is made of the DC generator of a Volkswagen Beetle. At the startup, Mr. Ahola starts the leaf blower , Mr. Pietarinen starts the fuel and Mr. Kiiskilä holds the box that has the ignition spark high voltage generator.

In this video we are conducting some test drivings on the parking lot with "eunuch 2". videoclip (11.2MB/61s)

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The turbine housing inlet. Melted turbine housing.

Turbojet meltdown. There are some risks when using a turbocharger as a jet engine because it is not actually designed for that. One of those risks emerged itself a few weeks ago. We were having an exhibition where all clubs of our university tell about themself and what they do. "suihkuvoimatekniikan kerho" was there also and we had several runs of our jet on the parking lot. The audience seemed quite pleased at least those ones that were allowed to ride on Eunuch II. The startup with the new electric start was a little slow. We had to heat up the engine a few times by running it on the starter and not spooling it up to self sustain. After heat up the engine did started well. We did noticed some sparks coming out of the jetpipe but it didn't seemed too bad. After starting and driving Eunuch II several times during the day we noticed at the evening that the thrust of the engine had dropped down to about 70% of maximum. After opening the turbine casing the reason of power loss became clear. The tips of the turbine wheel had melted off. That is about 0.5x0.5cm from every wheel tip. But the turbine casing had lost even more metal. About 0.5kg of cast iron had literally burned off! The wall that divides the turbine housing in two parts has almost gone and big chunk of metal is missing on the housing's inner surface also.

Turbine wheel, top view.	Turbine and shaft.	Turbine wheel, side view.

The leaf blower with tuned 2-stroke engine Mr.Ahola building the leaf blower.

Building the new engine. That was a reminder for us that the temperature in the turbine housing may not get too high. So we consulted our pile of turbocharger parts that is got from our sponsors and from local junkyards and built a new engine. ( Eunuch Ballbreaker Mark IV or EBM IV for short). We also added a temperature sensor in the jetpipe just after the turbine. The measurements showed that the temperature got up to 700 C at the startup but dropped to about 400 C when the engine was running low power and got back up to 500 C at full power. We had changed the electric motor from the starter back to the original two-stroke gasoline engine to get more air and to achieve a startup without preheat. The starter engine was also tuned for even more power. So we don't know how hot the engine got with the electric starter but with this one it seems to operate well below it's melting point. We tested the thrust from EBM IV and it might be even more than from the previous melted one. The compressor inlet is bigger and we had to open up the jetpipe too to avoid compressor surge. So in theory the thrust should be bigger too and we will measure it later when we have time for that.

Mr.Pietarinen welding the EBM IV.	The pile of turbocharger parts. Notice the afterburning jetpipe in the blue plastic basket.

Eunuch2 at the center of Tampere.

Eunuch2 meets the Capital of Finland. The new engine had very promising first appearance. There were a campaign against "cough potatoes" arranged by the technical universities of Finland. We were with the campaign and run Eunuch II at the center of Tampere. The place was just aside with the local bus station and the noise and smoke from the jet did got a good audience. The main happening of the campaign was on Senaatintori which is in the heart of the Finnish capital Helsinki. At this place the Eunuch II got the attention of even more people. Next day we were back in Tampere and Mr. Ahola drove the speed record for Eunuch II - 87.5 km/h !!!

Eunuch2 on the Senaatintori in the center of Helsinki.	Riding Eunuch2 on the Senaatintori.

The quest for more thrust will continue. We have built a new rig for that has a personal scale fitted on it. This scale will work as a thrust gauge. The system has also two ball beared sliding tracks that will allow the turbojet to move against the scale. Our new RPM counter will also be ready soon since I ordered the required components today. The rig will work as a test platform for different turbojets we will build and test. When the system is finished we will have an easy way to change the configuration of the turbojets and instantly measure the changes in RPM, temperature and most important in thrust.

Some pictures taken during the building of Eunuch2.

Eunuch2 without engine and paint.	Eunuch2 getting a new paintjob.	Getting the pieces of Eunuch2 together.	Mr.Ahola building a thermal cover.	The combustion chamber and turbine housing painted with thermal paint.	Constructing the glass fiber fuel tank.

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Last update 24.11.2005 S.K.