ravill

My Feedback: (11)

Best.

News.

Ever.

Now we need the OK to run 2 stroke oil in all of our turbines and we'll be all set!!

So come on Redman, can we, huh? Huh?!

DiscoWings

My Feedback: (76)

[QUOTE=Dave Wilshere;11723045]That doesn't make sense, perhaps on a p-80 sized engine where the thrust is small, but on a large p-200 or larger you will see a difference, I see power improvements of 1-2 lbs on my 180 sized engines both KINGTECH an Behotec, I'm sure this will equate to a 2-3 lb on a jet cat p-240.

Henke Torphammar

Why do they gain power? If diesel holds more energy it would result inte less fuel needing to go in the engine. If the pump are kept at the same PW of course power will increase, but so will RPM.

I do not know how clever Xicoy are compared to Jetcat. I can however imagine if just switching fuel in the bench just reading the scale for thrust the engine would run at a higher rpm before ECU have adopted it self.

What do you guys think?

DiscoWings

My Feedback: (76)

jetcat ecu simply go up to the max rpm that is set, so whatever is needed fuel wise to get to the max rpm it doesn't matter what thrust is being produced.

Karsten022

We are flying our Frank-Turbines (www.frankturbine.com) with all sorts of fuel (Diesel or Jet A1 or a Mix of them) what we could get. Also Mr. Frank has made a lot of Testruns with DIesel or Jet A1. But what we found out is that the Thrust of the Turbines is about 0,4 KG less than with Jet A1. We didn`t find out that there is more Power with Diesel.

Karsten

husafreak

My Feedback: (3)

I just started out running diesel in my Cheetah with 2.5% two stroke racing oil. It is just so easy to get. I agree that it puts out more smoke on shutdown. I do not know if the different brands available here in the states run differently. I am using two different stations locally. I did not realize this was something new as I am new to jets with only 70 flights on the Cheetah. I like that diesel doesn't really smell bad. I know from work that Jet A is hands down the worst smelling stuff to get on hands or clothes. I thought owning jets would mean a stinky garage, van, etc. but with diesel it has not. I think it is great that JetCat will allow it. I look forward to my 25 hour service to find out if diesel is harder on the turbines or not.

mr_matt

My Feedback: (10)

I have run diesel in a P-60 for a long time. Maybe 2 years or more. It seems to have had no deleterious long term effects. It is SN 22 or something and I have had 1200+ flights and it has been in for work twice, new bearings only. Pretty reliable.

I will say however it runs_much_rougher on diesel (sometimes so rough on transition you think it might quit). On K-1 it is smooth as silk.

I would look at this decision (kerosene vs diesel) less as a long term reliability question and more on the operating stability of each turbine individually. Just my opinion.

dbsonic

My Feedback: (3)

Do we know if there is any greater chance to flameout with diesel? or is the probability about the same as that of kero. I supposed most flameouts are due to plumbing and filters more than fuel type?

Mi-25

Hi Dave,
I'm using Diesel in my Kingtech and apart from some popping during the fuel ramp phase and some smoke after shutdown it's fine. Best thing is that there is almost NO smell. If Kero leaks or gets on your hands one can really smell it! You can rest assured that the diesel (the type we get in Hong Kong anyway) does not smell.
cheers,
Leon

Mi-25

I use Diesel in my Kingtech...and the factory rep tells me that it produces slightly more power than Kero...no added risk of flameout...most of them are due plumbing/blockage/air bubble issues.

Henke Torphammar

It sort of shows you the true face of your engine. If it runs well on diesel it's a good design with proper evaporation etc. If it runs rough on diesel things can be made better which would benefit Jet A1 use too.

DiscoWings

My Feedback: (76)

the roughness can be smoothed out with tweeks to the ECU, in general, you need less diesel than kero to get your turbine started.

But for the most part yes, Diesel will be a little rougher than kero in acceleration and start up, and certain turbines like Behotec / Kingtech and YES Even Large Jet Cats will produce 3-4% more thrust at the same RPM. Just tested my

JetCat 240: 56.7 lbs K1 Kerosene
Jetcat 240: 58.5 lbs Shell V-power Diesel
40 degrees Fahrenheit outside temp, 300 ft sea level

paulhat

Thanks for taking the time out to do the tests Disco. Interesting results.

Hey did you have to change ECU settings to get your jetcat to run on Diesel?
With the Kingtech you certainly have to.


Paul.

DiscoWings

My Feedback: (76)

I haven't had time to change jetcat ESC settings, however, on both Behotec and Kingtech the 1 common is LOWER PUMP START voltage and Ramp Up voltage.
2ndly Increase glow power if possible for the ignitor. I will start tweeking the jetcat esc this weekend.

All thurst was measured using Medusa Tech e-reader with the thrust plate. turbine was on a ball bearing rail mounted wood block.

Henke Torphammar

Same actual RPM? not only same preset?

husafreak

My Feedback: (3)

On my Cheetah I ended up (following the directions) lowering the Pump PW Ign. K value from the default 031 value to 015. This is the start sequence fuel used to bring the turbine up to temperature for the pre heat cycle to start. So it is much lower than expected with diesel. Note that it started just fine at 031. Below 015 the starts got longer and below 013 it would not start.

mr_matt

My Feedback: (10)

What would those tweeks be?

DiscoWings

My Feedback: (76)

Full power RPM was the same, 110k for the 240 this is set by the ESC, it doesn't really care what fuel it uses as long as it can get to the MAX RPM that is defined in the ESC, it can be OVER CLOCKED/ Err Over Thurst to 112K RPM at which point the diesel should put about 60 lbs or so.

Henke Torphammar

I know the limits, but they not for a fixed pump value they are also adopted by the ECU hence asking if you read the GSU at the same time. The older fadec units can overshoot for a while before adpoting and the manual states you need to fly the plane a couple of times for a good adoptation. The jetcat ECU I do not know, so asking. So now the questions are answered

DiscoWings

My Feedback: (76)

I haven't messed with that, I'm using the V6 gsu, I talked with Bob regarding this and he said as long as the pump voltage doesn't go over 6.5 volts it the learning will be fine.

My max on diesel was the same as kero 6.03 volts.

mr_matt

My Feedback: (10)

So what are the ECU tweeks that smooth out the roughness?

stevekott

Hey Matt,

Is your roughness experienced just during start up or is it also on the 'transition' from idle to power-up?

mr_matt

My Feedback: (10)

Both. Disco said he has some ECU tweeks to smooth things out. I hope he shares them.

thespit

So happy to hear this ,local airport won't sell jet a1 to me, 240 klm round trip to get it.

pedro w rdz

My Feedback: (4)

What brand. Of 2 stroke oil are you guys using?

Thanks