New TurboJet build

[tasjet]

G'day all,


First time poster looking for some advice.


I have 2 Cat diesel turbochargers that I am trying to work out which one will be the most suited to build with. I plan on using ATK or diesel for the fuel. I have access to some Herman nelson nozzles and nozzle holders that I will be experimenting with once I work out which turbo to use.


Turbo 1: 62mm compressor inducer, 75mm turbine Exducer.

Turbo 2: 55mm Compressor inducer, 57mm turbine Exducer.


I am lead to believe that Turbo 1 would be better suited to the application with the larger difference between the inducer and exducer dia. Would this be true?


Both turbos are not gated and the smaller turbo would be much more convenient to build with as it isnt as big and clunky as the bigger old school cat turbo.


I will disassemble the most suitable turbo and get some more dimensions once I work out which one to use.

Looking forward to your comments.

Cheers,
Sam

[enginewhisperer]

yep both should work, but #1 will probably be a better match for turbine engine use.

[racket]

Hi Sam

Yep , go with the bigger unit , it'll give you less problems

Cheers
John

[tasjet]

Thanks gentlemen,

I'll disassemble the big one tomorrow if i get a chance and work on setting up an oil system to make sure that everything is o.k.


Sam

[tasjet]

So it's been a bit longer than I though it would be but I have finally tested the oil system and got some more measurements as I said I would. I forgot to mention that my turbo is a twin scroll setup aswell.

Starting with the Compressor:

Inducer: 62mm

Exducer: 87mm

Turbine:

Inducer: 84mm

Exducer: 74mm

I have been looking into the fuel nozzle side of things and have found a 6GPH 80 degree semi hollow boiler nozzle. This flow is at 100PSI and is good for in excess of 300PSI. I have access to various different boiler pumps also. One of the smaller ones is rated to about 11GPH at 10 bar (145psi). I'm thinking this will be okay but what does everyone else think? Will this sort of flow work with my turbo?

Cheers,

Sam

[racket]

Hi Sam

Your airflow will be ~1 lb/sec , so fuel flow ~1 lb/min or 60 lbs/hr or ~8 USGPH .

Assume you run a max P2 of 35 psi , leaving a 65 psi pressure drop across the nozzle at the rated 100psi , square root 65 is ~8 , so 8 GPH divided by 0.8 =10 GPH nozzle if only 100 psi , but if using your 145 psi potential then theres a 110 psi drop , sq root 110 = 10.5 , so 8 div by 1.05 = 7.6 USGPH nozzle.

Yep , your fuel bits should be OK , theres always going to be some fine tuning once the engine is operational , as long as its ballpark to start with you'll be right :-)

The stainless Steinen nozzles www.steinen.com/nozzle-information/ I used were taken up to ~1300 psi at one stage of the Garrett TV84 engine development ,but reduced to ~750 psi in its final form with a larger nozzle.

Cheers
John

[tasjet]

Perfect thanks John.

I have found a couple of the steinen nozzles but they are both 60 degree patterns and one is 6GPH SS and the other is 4GPH S. I'm thinking that the Monarch 6GPH 80 degree one that I mentioned before would be better suited. I'm not in a position to purchase anything so i'm just using what I can find. Luckily I have access to a lot of good stuff to make it work. I might be able to experiment with the different nozzles once I get it up and running anyway.

Time to start with the flametube this week.

What I've worked out so far is that the minimum size would be approx. 107mm dia and jetspecs calls for 131mm. I think I have some 5" stainless tube that would work, if not then I will roll to a dia of approx. 130mm. I will drill 10 holes in one row for the primary to the same area as jetspecs and place them at the point that the fuel will contact the tube. I will then do everything else as per jetspecs.

Cheers,

Sam

[tasjet]

G'day All,

I have finally been making some progress with the turbojet build.

I have tried to attach some pics but the application is blocked on the network i am using unfortunately. I will sort something out when I have some more time.

I have a couple of questions aswell. I used a large fire extinguisher for the outer body as it was all that I could find that was relatively close. It has left me with approx 1" gap between the flame tube and outer body. Will this be fine?

Secondly, I am looking into the ignition system. Will two large electrodes like what are used in industrial boilers be enough to ignite the diesel/ATK? I'm looking for a simple setup and would prefer not to use a built in lpg starting system. If I had a small port for a butane torch that i could get ignition with and then remove the torch and block the port would that be ok?

Thanks,
Sam

[turboron]

Sam, I think the most straight forward approach is to use a Bosch relay, a spark plug, a 12 volt automobile coil, condenser etc. Youtube has howto videos.

Thanks, Ron

[racket]

Hi Sam

1 inch gap will be fine .

Initially I'd be looking at adding a LPG pilot light system to make those first few starts easier , theres nothing worse that not being able to get the fire alight on a new build , it can always be removed at a latter date.

A very simple and crude bit of plumbing to get the gas flowing past the spark plug is all thats required

Cheers
John