RE: Jet Central Flea??
 

Is 195K RPM, six pound thrust? Will like to have an apples-to-apples comparison, as you can always throttle down in the wren.

RE: Jet Central Flea??
 

WREN WM44 Gold Full autostart:
195,000 MAX RPM
4.3oz/min
8+ pounds of thrust

I know...I have one!

Dave Rigotti

RE: Jet Central Flea??
 

The flea looks promising!!!

...........................flea................... .......wren
weight..................340g...................... ..468g
diameter...............60mm......................7 5mm
length...................136mm.................... 135mm
fuel consumption....2oz/min...................4.3oz/min
Thrust...................6lbs..................... ....8
price/manual.........$2?00?....................$2295
***Added....Price still being determined on the Flea****

Between fuel and turbine weight the flea looks pretty good. Price?

RE: Jet Central Flea??
 

The turbo prop system is flying now for over eight months. R and D are complete with many hours being put on test flying. Our unique (do not ask) gear box system is turning the prop at 8000 rpm producing in excess of 50 lb of thrust.

We have flown this system on the Graupner Raven as well as other airframes. Currently flying in the Ultimate biplane, we are very pleased.

Production will begin very soon with release later this year. The package will be a complete autostart system ready to mount in the airframe of your choice. Additional turbine exhaust preformed will be included for those who have the need to go further out away from the cowl. With the exception of the ECU, this package is engineered,manufactured and assembled in-house. The sound of this turbo prop will simply astound you!

We will be competatively priced with warranty and service second to none. Stay tuned for information as it becomes available.

Last, for those who want to get on the list, send me an email and you will be added. Please be sure to include a phone number where you may be reached.

Thank you to all for your continued interest and support. You are clearly sending a message that our product is without question a superior product and our service is second to none.

Thank you,
Eric Clapp
Distributor
Jet Central manufactured Turbines
jetArtes Gulf Coast
www.jetartes.com

RE: Jet Central Flea??
 

how about a one minute Wav file in Windows Media Player to give us a TASTE of the sound? possible? i m willing to bet if it sounds as good as you say ( which im SURE IT does) then you ll only create more pre orders on noise factor alone.....

Tim

RE: Jet Central Flea??
 

the suspense!!!!!!!!!!!!!!![X(]

RE: Jet Central Flea??
 

With all due respect and speaking personally I think it is unfair to both companies comparing these 2 engines,....2 completely different size/thrust classes.

Both companies have worked extremely hard at creating their own distinctive brands and both engines have/will have their own place in the market.

Rob.

RE: Jet Central Flea??
 

i agree[:-]

RE: Jet Central Flea??
 

the comparison was on much fuel was consumed/min between the Wren and the Flea... though they are a bit different, the size of each seem relatively close for end use.... you may get a bit more of the wren but in a smaller jet, it may be a bit much. and vise versa. i dont think the comparison is ment to degrade either product, just show the unknown differances between them... which for me personally, could help determin which is a better fit for a build/conversion.
after all, this is what free trade is all about... design it, build it. market it, sell it. fly it, crash it, rebuild it, start all over...... you ll still end up with as much time and money ivested into either.... no bashing here. just cold hard facts.

no offense intended.
Tim

RE: Jet Central Flea??
 

I AGREE:D

RE: Jet Central Flea??
 

What I want to undertand is how much fuel is the wren consuming when it's pushing 6 pound of thrust. Is it more than 2oz/min?

RE: Jet Central Flea??
 

if i read what rc guy is saying the Wren is eating 4.2 oz fuel per minute giving 8 lbs thrust, if its a simple math product (which i doubt) it sould eat 3.1/oz of fuel per min at 6lbs thrust, but i KNOW its not that simple of a calculation... i would assume there are other factors to weigh in. like load/rpms at 6lbs. fuel/ set up. how efficent the bur is, ect... will all effect fuel per min consumption.....
but i have NO turbine experience, im gettin learnd! lol. but the logistics are there, i just dont know how to arrange them to get the numbers your seeking.
Tim

RE: Jet Central Flea??
 

What makes you believe that 2ozs at 6 pounds is correct?

Dave

RE: Jet Central Flea??
 

for the Flea? thats what was stated by the manufacturer.....see begging of thread.
Tim

RE: Jet Central Flea??
 

*

Dave

RE: Jet Central Flea??
 

The comparison wasn't meant to be 'this one is better than this one'. It was to show usable applications between the 2. The flea could be used to keep a jet very light with the low fuel consumption and the lighter weight of the turbine but has less thrust. It also has a slightly smaller diameter which could fit a little easier in some jets. The wren is a proven design, weighs just a little more, uses a little more fuel which translates to a little heavier airframe but puts out more power so you could also go with a little larger jet... The price could be a major factor in determining which way to go...

Turbines develop a majority of their power/thrust in the last, lets say, 1/4 of the throttle range. I'm not sure if the fuel consumption is exactly porportionate to that. The wren could probably be rpm limited easily enough to only put out the 6lbs though...

RE: Jet Central Flea??
 

The Flea fuel consumption is an average 'real world' figure that flight time/fuel capacity/weight/wing loading calculations can be made from. As Eric said..in the test airframe with a 20oz tank the Flea has a duration of 9 mins + take off + gear check circuit & landing.

I think the design philosophy behind the 2 engines are further apart than it might appear, the Flea should appeal to those minimalists seeking nano turbine low installed size/weight, this does require more user involvement during the start process.

Hope that helps, Rob.

RE: Jet Central Flea??
 

In reply to your question, Edgar, we don't have a fuel consumption figure for the MW44 when producing 6 pounds of thrust. We have the latest figure for full thrust for the MW44 Gold - 145 ml/min (5 oz) and the figure for idle - 26ml/min (0.9 oz) but not the ones between. The figure is higher than the original MW44 (122 ml/min 4.3oz) but that is because the engine is producing more thrust. The amount of fuel used relative to thrust produced remains the same.

There is a formula which can be used for checking fuel consumption figures. The Gas Turbine Builders Association have been running an annual Engine Efficiency Competition for about 7 years, where a number of different engines are run on the same test equipment, giving an independent, accurate comparision. Over the years, the statistics show that no matter what the size of engine, it will use between 30 and 50 ml/min of fuel for each kilo of thrust produced. The lower the number, the better the engine efficiency. The best figures acheived have been in the low 30s - last year the Merlin won with a figure around 34. The previous year we acheived 35 with the MW54.

I have checked the figures given for the Flea using this formula. 6 pounds of thrust is 2.72 kilo, and 2 oz of fuel is about 60 ml. Dividing the amount of fuel by the thrust produced (60 divided by 2.72) we get 22. So it appears that the Flea is not only smaller than other engines but that the Jet Artes team have made some sort of technological breakthrough, as no engine before has come anywhere close to this figure, according to the independent tests.

We look forward to seeing this amazing feat repeated by the Flea when it is entered in the GTBA efficiency competition this year. Unfortunately, not many manufacturers submit their engines for the competition - only JetsMunt (Merlin), Wren, Behotec and Phil Heward. It is surprising that neither JetArtes nor JetCat submit engines, as according to the published thrust and fuel consumption figures on their websites their engines are acheiving an efficiency far beyond any others. On this basis they would be sure to win by a huge margin if they entered the GTBA competition. So why don't they?

Sara Parish
Wren Turbines

RE: Jet Central Flea??
 

O.K....:eek:.. How much fuel per min does this little gem use at full power...

RE: Jet Central Flea??
 

I don't know what the figure is for full power, certainly it will be more than 2oz/min. Hopefully as soon as I have mine I'll let you know. All I can go on for now is the 'average' figure from Felipe in that particular airframe.

Rob.

RE: Jet Central Flea??
 

During these R and D...Errrr.... tests... what did the fuel consumption at full throttle /speed prove to be ...?

or... what figure was quoted for the fuel consumption on the four sold /10 signed up for.... lets face it no one buys a turbine not knowing what the fuel consumption is at the stated max power...do they..?...[:-]

Brg ..Dave.

RE: Jet Central Flea??
 

Ah.. . very clear and easy to understand answer... Thanks..

RE: Jet Central Flea??
 

Hello Sara, hope everything is well, hello everybody,

No Sara we have not made any technological breakthrough so far.
As Rob said, the only fuel consumption figure ever stated by me is that I'm able to fly my Flea converted Rapier for 9 minutes on a 20 oz. fuel tank on a "normal" flight. What is "normal" flight ? well, it is difficult to say, not all the time at full throttle but not all the time at half throttle. This information is useful for people trying to decide which airframe with which fuel tank, and only for that, it is not intended to be for your efficiency contest.

The estimated full throttle fuel consumption, and I want to underline ESTIMATED, is going to be around 3.4 - 3.5 oz. per minute. Final number will be given only when the engines are ready for production because we are still running tests and fine tuning. Hope this helps

Best regards
Felipe

RE: Jet Central Flea??
 

Dave:

Please review the beginning of this thread. You will see several (3) pictures posted by my colleague in the UK. One is of Felipe Nieto holding the delta wing test bed for the Flea. The Flea has been and continues to fly using this airframe. As previously stated by myself, a new airframe is about to take flight as well; L-59 Albatros from Hobby Lobby International.

Reviewing basic mathematics, we fill a 20 ounce tank, taxi out, take off and fly. We land within the time frame of 9 to ten minutes and taxi back. Not only is there fuel (small amount) remaining in the 20 ounce tank, but the UAT remains full as it should. That my astute readers and friends is 2 ounces (or even slightly less) per minute. You must interpolate into this basic mathematic calculation, that the nine minutes flown is not WOT. Few if any pilots I know of fly WOT from take off to landing. There is little or no logic in this type of flying. What is important here is you can fly nine minutes on 20 ounces of fuel enjoying this little gem while it pushes the airframe of choice through the flight routine you have chosen to fly.

For those of you seriously interested in WOT fuel consumption figures, we will test this and post it. The value of this figure is not as important as the value of normal flight / fuel consumption.

Our Rhino @ 36 lb of thrust consumes at WOT 17 ounces which is about the same as the Titan. However, take into fact that those who have purchased and flown the Rhino report less fuel consumption because they now can fly the throttle stick due to the Rhino's very fast throttle response. No longer a need to worry about spool up times. Fuel consumption feedback from our customers is in the 14 ounce per minute range. The point? Customers are happy getting better results than WOT consumption. Customer satisfaction is what is number one on our list of priorities.

Rob is totally correct when he states this is not a comparison between Wren and the Jet-Central Flea. Both companies produce fine turbines each having their own niche in the market place. Each with their customer being the most important factor in their business.

Sincerely,
Eric Clapp
Distributor North America
Jet-Central Turbines
www.jetArtes.com
jetArtes Gulf Coast

RE: Jet Central Flea??
 

I think the problem is just that what is "normal" for one pilot or aircraft is frequently different than what is normal for another pilot or aircraft.

I'm sure others may have different approaches, but for me it's kinda useful to know maximum fuel consumption figures of any engine I'm using so that I can set my timer initially to the duration indicated by maximum burn, then fly several flights checking how much fuel I come back with each time - that lets me fine tune my timer based on *MY* normal flying for the given airframe, rather than on someone else's (or even on mine for a different airframe that may be more or less draggy).

Good luck with the engine - it looks quite impressive.

Gordon