Will it burn?
 

Hi

I have been reading several instructions manuals from turbine electronics (Jetcat, Projet...) and still don't know if it will burn....the gas that is.

I am planning to put the gas tank inside the airplane (that as not yet arrived[:@]), but I would not like to take off with a small gas bomb inside the airplane. Do these modern ECUs allow to burn all the gas contained in the tank in the start-up procedure?

Thanks

Nuno

RE: Will it burn?
 

No

RE: Will it burn?
 

i think jetcat ECU from V5 yes..you can set somewhere to dump onborad gas.

RE: Will it burn?
 

Jetcat does give you that option, or simply start with the gas container outside the aircraft and disconnect. Bob

RE: Will it burn?
 

Nuno, usually the small internal gas tank will allow to perform 3 starts. So to answer your question, NO, the ecu will not burn all the gas from the small gas tank. If you don't want to have the internal tank in the airframe for saftey purpose is ok. Just use external source to ingest the propane for the start up. Don't forget that you still have to install the gas selenoid, it will regulate the pressure in the start up secuence. A lot of us don't like the internal tank for the same reason.

Good luck
Alejandro

RE: Will it burn?
 

I don't even use the gas solenoid . I regulate the gas by sound and EGT . It's actually very easy and I can furher simplify the installation.

Marc

RE: Will it burn?
 

Hi Nuno,

The JetCat ECU will allow the burning of all of the gas. I cannot speak about any other brands.

Hope that helps,

RE: Will it burn?
 

I bought a regulator value for the Coleman propane tank:

http://s43500.sites99.storefront-hos...ail.aspx?ID=50

You can just plug in the gas line to the turbine and open the value one click when the turbine first spins up. It works great and doesn't require an onboard tank or ECU valve...

RE: Will it burn?
 

Odd question based on the fact you are worried about a potential 'bomb'. This is such a small quantity of gas it is nothing in relation the the real 'bomb' - your 3 odd litres of kerosene if you hit the deck and the turbine goes through it! Don't worry about it, there are thousands of gas start turbines flying, this is not a common problem. Buy a kerosene start Jetcat of you are that worried.

:eek:

RE: Will it burn?
 

Seconded plus nothing like looking on the bright side ayy.

RE: Will it burn?
 

FWIW, the link above is what I personally recommend to all Turbine jet guys that are interested in off board starting methods. It is the smoothest valve I've used and or seen for this purpose.

RE: Will it burn?
 

Here is mine from a portable gas stove. I found it in the junk parts bin at the hardware store and added the fitting.

RE: Will it burn?
 

Sean or Marc,

What is the indicator on the JetCat GSU that tells you to turn the propane feed off using your described method? Is it when UAccel 2 shows, or the Temp or by sound??? I would think that when the turbine begins to ramp up past 24,000 RPM would be the time to switch off the propane feed.

Can you provide some details how you guys go about using this method? I like this idea of not having the extra valve and tubing in the jet. I suppose the ECU just goes through the motions whether the valve is connected or not.

Also, Do you plug the one-touch fitting on the turbine after the start sequence?

Thanks, Ken

RE: Will it burn?
 

I used it for a manual start engine. For the JetCat I would leave the gas solenoid in place and turn the gas on at the start. Let the ECU take care of opening and closing the gas valve. When startup is complete just turn off the gas and disconnect. I'm not sure if the ECU looks for an operating valve or not as I haven't tried it on my JetCat.

RE: Will it burn?
 

Ken, you need to put a check valve on the 4mm line that goes direct to the turbine (of course you will need to come down from 4mm to 3mm for jetcat). The check valve is paramount cause gases will come back up the line if you don't have it and will melt a festo fitting inside the engine (ask me how I know).

Then hook up the regulated propane, put a click of propane as the start sequence starts.

I don't even look at the GSU anymore, but I think I did when I first started.

You can hear it light off, and start up, when you think you are at sufficient speed and temp (I go by how it sounds, and I'm way accurate), shut it off, and pull the 4mm line off the check.

If you have any probs or questions, pm me for phone number, I'll walk you through it. It's easy, and IMO the best way to do this. I've turned over at least a dozen guys to this.

RE: Will it burn?
 

Yep, the check valve is needed even if you use the gas valve in case it sticks open.
The nice thing about using the off board propane is that you don't even have to change any plumbing and can leave the onboard tank in place if you like. To save space take it out.

RE: Will it burn?
 

Sean,

Thanks for the tip. I wouldn't do this in my Rookie as the engine is not very accessible. However, in my X-tremejet Rafale I might try this. The turbine Festo fitting for propane is right there easily accessible.

Before you mentioned this starting technique in this thread, I came up with my own way to remove the propane tank and associated fittings from the Rafale. What I did was I made the tank, 4mm OD tubing, check valve and manual shutoff valve all one assembly via a 3-way SMC one-touch fitting. I then plug in this assembly to an onboard inline SMC 1-touch fitting, which goes directly to the solenoid valve. I go through the start sequence and then remove the assembly once the manual shutoff valve is closed to keep the reserve propane in the tank from escaping. I save a little room in the nose section by doing this as well has keep the install clean.

Ken

RE: Will it burn?
 

Accessing the engine has nothing to do with this. You run the line from the engine all the way up to where your fuel fill line is. When you fill the airplane with fuel, you have a 4mm dingly there with a check on it, ready to go.

RE: Will it burn?
 

Hi Sean

What do you mean by paramount? Do not understand how can the Festo fitting melt. Do you mean if it is near by the turbine?

I probably go with an outboard gas installation, but anyway what is the Jetcat menu where you can burn all the gas in the start-up procedure?
Regds

RE: Will it burn?
 

Inside the turbine, just underneath the cap on the front of the turbine, are a couple of Festo Fittings!

One of them is the propane entry to the turbine.

If there is not a check valve on the propane line, hot gasses when the turbine is running, will run up that line and melt the festo fitting inside the turbine cap.

This will cause no issues for you until you land, refuel, and go to start your engine again.

Propane will leak at that melted festo fitting, and you will come close to blowing yourself up, if you ever do get the engine to light off!

One day, while learning this, I shot liquid propane down the light trying to figure out what the hell was going on.

When that kicked off, oh boy, was it hot in my garage!

Thought I was a contender for the Darwin awards that day. I was on the phone with a buddy, dropped the phone while I was jumping to the fire ext and compressed air hose! :D

RE: Will it burn?
 

under LIMITs, Drain GasTank enabled. If enabled, after turbine is started and throttled up, the starting gas valve will open, draining the tank.

kc

RE: Will it burn?
 

Thanks guys

So does this means that when I got my 160, I should take the front cover and install a check valve on the gas line? Shouldn't the Festo fitting in the turbine be a check valve itself?

Nuno

RE: Will it burn?
 

You could do that, but then when you gas the airplane and pull the source off, you'll get more wasted gas, and It till be tight in there for a check valve.

RE: Will it burn?
 

A check valve ANYWHERE in the gas system will do the job, at the turbine or at the fill point.

RE: Will it burn?
 

Seanreit,

I am so totally new to all of this (just got my first turbine two days ago) and I am installing in my Baby Boomer...could you post a drawing of the gas start system and where you recommend the check valve? I have a propane valve, if I use that do I need the check as well? I intend to keep starting gas off-board if possible.

Please Advise....

Thanks!