turbine boat question??

[Jesse James]

I have heard the turine boats around the docks make a noise like a am radio losing tune... it is in this video at around 2:40 and throughout the rest of the video

http://www.youtube.com/watch?v=KQdY_...eature=related


also in the powerboat article they were talking about the throttle set up in copelands phenomenon...and it lead me to believe they had to do some engineering to get it down from 12 levers, and they indicited a seperate throttle for n1 and n2......

what is n1 and n2 and do they require sperate throttles and if so why?

thanks...

[GENERAL LEE]

As little interest as I have in owning a turbine boat, I'll ALWAYS watch them run!

Was that Hellfire? It doesn't really look like I remember it, but it's been a few years since I've seen it.

[insanity]

As little interest as I have in owning a turbine boat, I'll ALWAYS watch them run!

Was that Hellfire? It doesn't really look like I remember it, but it's been a few years since I've seen it.

Nope not Hellfire, Hellfire's cockpit is a lot smaller and its exhaust is at the transom. But still sweet!

http://www.youtube.com/watch?v=j4Tr0syhIIo

[phragle]

this might help...

http://www.aircav.com/cobra/T53-703.html

[Chris]

N1 is the compressor stage. The turbine compresses air prior to combustion just as a piston engine does, but in a linear fashion using a multiple-stage turbine compressor. Each stage having a more aggressive blade pitch. The output of the compressor stage is ported into a combustion chamber, the fuel is injected and ignited and the output is ducted to the power turbine, N2.

Just like an engine there are RPM limitations. Both stages' RPM is a function of fuel input and load. The other limitation is exhaust gas temperature. Essentially, too much fuel and not enough load will overspeed the turbine- typically the N2 side first. Too much fuel and too much load will probably cause EGT related failure before the N1 overspeed issue occurs.

A gas turbine is in simple terms a jet engine blowing against a fan. The fan is connected to a shaft and then a gearbox that reduces output RPM and converts that speed into torque.

All you need to control a turbine engine is a single lever to either mechanically or electrically open the valve on the fuel metering system.

[boostbros]

the really loud screeching at idle is from the bleed band being wide openreducing the air into the combustion chamber so as to not blow the flame out the more power a turbine makes the quieter it gets as all the air is forced thru the engine... some of the sounds you hear docking are there is a large disk brake on the output shaft with often 2 calipers they use a trim pump for brake pressure and can stop the n2 or power turbine to shift when released it sounds like blowing compressed air on a bearing as the blades spin up to speed.....all the blades in a turbine are hollow and have air blowing thru them to cool them thats what a hot start is to big of fire with not enough cooling air inside the blades then they can melt or bend with not good results!

[KnotRight]

the really loud screeching at idle is from the bleed band being wide openreducing the air into the combustion chamber so as to not blow the flame out the more power a turbine makes the quieter it gets as all the air is forced thru the engine... some of the sounds you hear docking are there is a large disk brake on the output shaft with often 2 calipers they use a trim pump for brake pressure and can stop the n2 or power turbine to shift when released it sounds like blowing compressed air on a bearing as the blades spin up to speed.....all the blades in a turbine are hollow and have air blowing thru them to cool them thats what a hot start is to big of fire with not enough cooling air inside the blades then they can melt or bend with not good results!

Yes and no

The Bleed band closes at approx 85 percent n1.

Do you know what happens if it closes too late?

Here is the compressor section before balancing
also pictured is a set of Stainless compressor housings.
These were designed for salt water application for the navy.

[Brownie]

I wish I had a picture of the throttle for the 4,500 HP Lycoming turbine in the 110' "Genrty Eagle". It was a ten-cent knob, about 1/2" in diameter.

[tommymonza]

What does the starter sytem look like and how does it work?

[Rik]

What does the starter sytem look like and how does it work?

The starter is a generator as this is a DC motor. Simply put, the input shaft to the DC motor is splined and fits into a right angle gear box which in turn powers a gear (via a shaft) that is attached to the Compressor.

Being that on these engines (T53's and T55's) this is a purely "live" connection when the compressor is spinning it in turn rotates the DC motor.

When one closes the shunt field on a DC motor it becomes a DC generator.

[KnotRight]

What does the starter sytem look like and how does it work?

Here is the Starter/ Generator as Rik stated it doubles as a generator.

There are two versions of these a 200amp and a 300amp.

I paid 2500 each for these off a guy who bought 5000 of these off the
Army

The three polls fit a 00 lug one is ground, one is crank windings and the third
is Generator. Look closely you will see the exciter little #10 lugs.
When you put B+24 to this it will produce up to 300amps respectively.

This runs with the N1 system off a right angle drive and is always engaged.

[KnotRight]

Here is a picture out of my Student workbook that shows the
N1 and N2

N1= purple... Gas producer
N2= red .... Power Turbine


Note the bottom of the n1 with the studs on the right angle
that is where the Starter mounts.
SCS makes a right angle drive that will locate that above the engine for easy
Access.

[Rik]

Luckily, the Lycomings have a starter generator. The T-58's don't have this nor do some of the others other there. Try attaching a 400 amp alternator to an engine that has no pulleys

[nthdegree]

Luckily, the Lycomings have a starter generator. The T-58's don't have this nor do some of the others other there. Try attaching a 400 amp alternator to an engine that has no pulleys

we do it every day..it's called a gearbox....

[ZBODaytona]

didn't turbine marine say they have a 50'V NorTech that has turbines with sound output at 89db? I seem to remember a post about that one day, just don't remember which forum and when. Though there was never any video posted of the boat.

[GENERAL LEE]

According to Randy Sweers, Canada Thrust has the biggest turbines in a pleasure boat. He said it pulls like a solid rocket booster.

[Rik]

According to Randy Sweers, Canada Thrust has the biggest turbines in a pleasure boat. He said it pulls like a solid rocket booster.

Not even close.

[40FlatDeck]

Not even close.

I like that answer....

[Rik]

I like that answer....

Hell, I've got nearly 5,000 hp in one engine alone.

[Chris]

Geico just sold their BIG motors to Bill Tomlinson for his new Mystic.