Mark H

I did write a responce to the above but i feel this is going no where and reliability in my humble opinion is every thing. Far more important than a few onces of Kerosine.

Mark Hinton. (Team Hammer)

WrenTurbines

Mark,

I have said nothing discourteous about anyone, I have continually repeated that we are not bashing anyone and all the information I have given is in the public domain.
This information about fuel consumption matters to me because I know we are losing sales unfairly, so despite being a very busy person I have taken the time to post.

Sara Parish
Wren Turbines

Edit:This was written in response to Mark's original post which he has now edited.

jason

My Feedback: (1)

Hello Mark,

so do you agree that it is important for manufacturer to give honest figures for thrust and fuel consumption?


Jason
Team Caravanland

jonkoppisch

My Feedback: (162)

If i bought a p120 to put on a boomerang XL and only received a p80, I wouldn't be happy. If i purchased a DA 150 for a 40% yak and only got a DA 100...... Maybe it would be good if the turbines were not rated at the max thrust but guaranteed minimum thrust.... I would much rather know the definate thrust than a maybe, especially when trying to choose an airframe/turbine combo that would give me the performance that i want. I can't afford to buy multiple turbines to get the power that i should have....

Gary Arthur

My Feedback: (29)

I am sure everyone wants a reliable engine. There would be no benefit to having more thrust if you loose reliabilty. What is wrong with having a reliable engine that puts out the advertised thrust and has the advertised fuel economy? Is that asking too much? Is that not what we expect when we buy an engine?


For example
If someone was looking to buy an engine. They look at the specs. They find two suppliers with very similar specs. You would think that it would be a matter of choice. Either way you should end up with an engine that puts out XX amount of thrust with XX amount of fuel. Now after you buy your engine and a friend buys the other, you have a chance to compare. You even put them in the same airframe. Now one aircraft ends up having superior performance that is blatently obvious. Would you not feel cheated?

patf

My Feedback: (4)

i agree with what Sara is saying. One thing to remember, these engines are not like IC or other engines. you can take the same parts bolt them together and you will get different results. there are assembly tweaks and other reasons why, essentially each engine has a personality. perhaps manufacturers ought to give a guaranteed minimum thrust as jon suggests... perhaps even defined at a 90% or some standard power rating so that it is considered a "reliable" setting. but to get a motor home, test it in an airframe on a far from "standard" day and it be off power 10% and go ballistic because you were cheated out of a few pounds is just silly. if you find an issue take it up with the manufacturer, if it is a problem that is "product" wide they will have to deal with that issue as well.

WrenTurbines

Pat is right that all engines are slightly different, but since manufacturers presumably test all the engines they should be able to hold back any which don't meet the spec. The only engine to which this doesn't apply is our MW54 kit. We can't test the engines because they go out in bits, so we give the 14 pound figure which should be acheivable no matter who has built the engine. MW54s built here usually give almost 15 pounds.

There are calculations available to compensate for ambient temperature and height above sea level. We have a barometer and thermometer on the wall here and know what an engine needs to be giving in different weather conditions for it to be correct on a "Standard Day".

Sara Parish
Wren Turbines

ravill

My Feedback: (11)

I'm of the opinion of exactly how I voted.

Engine manufactures probably should give accurate numbers. Its the "right" thing to do.

Raf

ghost_rider

My Feedback: (20)

PMFJI but I know how to resolve this problem and give you guys an independent and unbiased opinion.

How about you guys send every turbine engine you make to the ghost, I will test them and post my findings provided that I will keep all the engines after the test for my hard work. How about that gentlemen and ladies.... (lol)

Anybody out there willing to help me test the engines?.......For your hard work you might get a freebie

On a serious note, what is important to me is that my engine comes close to the expected specs in terms of power output. A deviation of +- 3 lbs would not bother me. When it comes to fuel consumption, it is all relative. The fuel consumption that the ghost would get flying an airplane would not be the same as Woj flying the same airplane. Why because Woj is young and would like to fly the airplane as hard as the airplane would handle so fuel consumption is relative.

The most crucial point for me when I select an engine is longevity and support. I will only fly a turbine engine with full support facility in US only. Not that I’m biased about turbines with support facility outside US but when in a pinch and I have to reach out and find somebody to talk to around 6 PM when I’m out flying after work, it becomes critical.

Few months ago at Spiderman, there was a friend flying a turbine without support facility here in US and his engine kept flaming out at every landing. He was unable to reach anybody to help him. We also had an engine without support facility here in US locally and the guy was trying to set it up and ran into minor problems. Because of the difference in time zone, he has to wait till the following week to get his answer.

We have a limited flying season here in the corn fields of Indiana and longevity and local support (US Support) of my engines is a serious contributing factor when I chose the turbine engines I installed in my airplanes.

FWIW, K-1 kerosene and turbine oil are very cheap. I drive big gas guzzling SUV and I wish my vehicles would get 1/10 of the gas mileage I get on my turbine airplanes.

One final note, when I select an engine, I would prefer to go with the type that most of my friends and the majority of the people at the events I attend flies. Reason being that when I need help, help would be few feet away from me.

My name is THE GHOST and I approve the message.

Ray Davis

My Feedback: (1)

As posted, this is kinda a dumb thread, isn't it......"Should manufacturers meet their (advertised) thrust/fuel specs". Duh....retorical isn't it.....is anyone really defending false advertising here ?!

To say, "Gee, my engine is down on thrust but I still like it...", as in earlier posts above....excuses nothing and is irrelevant and hardly pertinent, here....or, "but it's so reliable", which is strictly anecdotal....haven't seen THAT spec anywhere yet except an occasional unsupported TBO number! Manufactureers do know exactly what their individual engines put out (they certainly oughta!) and should enclose the test data sheet stating the test conditions...with a listing of measurements corrected to a Standard Day. Or, as Wren does, so conservatively advertise, that all their engines can easily meet the stated values. W/o that, or STD corrections noted, the info is almost worthless to buyers!

Manufacturers: If it doesn't measure up...don't ship it until it does...period! Or get real w/ the specs/advertising.....there is just no excuse.

Ray

Doctor J.

Sara,
It has been my experience that most buyers buy because of what they hear. Not always because of the facts. There are certain manufacturers that seem to be untouchable. Be very careful. If you expose them their groupies will descend upon you like rabid dogs. So don't mention flame-outs, Electrical problems, or things like ESD because there will be a slew of them to come to their defense and say that all problems are self induced by the pilot. I agree that manufactures should be honest. I will also agree that some are not or just plain lie.If there is ever a standard established we at AMT USA, LLC. will be happy to have our product tested. Another way that a manufacturer can inform the public is to send a report with the new engine stating the ambient temperature and barometer reading when the engine was tested. I met some of the Wren guys at Toledo last year and found them to be a great group. There are lots of choices out there and some good products. I believe we have a great product also as do most others. I would just like to see the truth told in these forums. There are lots of things said in these forums and in print that are not true, which you have discovered. Sometimes it can be down right brutal and hard to stomach. They cost you and I sales. I would also like to see an honesty meter on the individuals that post such things. The one problem that I see with these forums is that people can say what ever they want, even if it is not true and there is no way to control that. I would also like to see the real names of individuals on the forums along with call signs so that we will know who they really are and to whom we send the letter sewing them for slander or liable.
Good luck and have a happy holiday!

John Ligons
AMT USA, LLC.

Ray Davis

My Feedback: (1)

Shoulda included the following, I guess, which I posted on another thread re figuring the trust correction:

"Sure, performance can be different in the air"....but it's damn difficult to tell...and if yer making an apple-to-apples comparison between engines, then you start w/ known and like conditions: A test stand. And those numbers (e.g. static thrust) will be a very good indicator of airbourne performance...which is much harder to quantify even in the same exact installation.

Re test conditions (ambient temperature and pressure the most important), for every 1000' increase in altitude, figure on losing as much as 3-4% thrust...same for every 10-degrees F increase (other factors involved, but 3-4% is conservative and fine for these purposes). The 'Standard Day' is sea level and 59F...the conditions to which manufacturers (should!) correct their engine performance. Same percentage the other way....i.e., on a 50F day, you should see a 3-4% thrust INCREASE. So, if a manufacturer says 10-pounds is max thrust under standard conditions (and it certainly implies it's no less than that at the stated RPM!), you might expect a total loss of 10-12% at 70F and 2000' ASL...and actually measure around 9-pound thrust. You can see that flying in Denver on an 80F day can significantly degrade performance....perhaps as much as 25%!

I can tell you that Wren is VERY conservative....a 44-Gold I tested at sea level and 40F measured 11.8-pounds, which is still around 11-pounds corrected. So, even on an 80F day, sea level, that 44 will still be exceding the Wren-advertised 10-pounds!

ghost_rider

My Feedback: (20)

Hmmmmmmmmm!!!!!!!!!!!

John

Anything mechanical and manufactured by a human is bound to have flaws. Even the space shuttle with billions of $$ invested in it had it own share of problems.

I’m an old timer in this hobby and I’ve seem them all. I’ve seen Ram engines shade blades. I’ve seen the early P-160 seize up, I’ve seen AMT USA engines seize up, I’ve seen Wren engines with serious flame out problems, I’ve seen Artes, Simjet and other turbine engines with some problems. The bottom line is when you have those problems, how long does it take to get it resolved and is it done to the customer’s satisfactions.

The problem I frequently see here is that some people would rather come in here in the open forum and complain about their engine instead of giving the manufacturer an opportunity to fix their problem. When the dust settles, they will go back to the manufacturer to get the issue resolved which to me is called “medicine after death�

Should the specs published by manufacturer come close to what they send to their customer?, Yes.
Should little % deviation from published spec be the determining factor when choosing an engine? No

You can get any engine that meets all the specs but if you can not reach tech support when you need it is like dressing up with no place to go.

JMOHO and please take it FWIW.



How many attorneys do you have on retainer? (lol)

Doctor J.

The Ghost_Rider is wise beyond his years. Thanks for the job that you do on the forums. You are a better man and have a better stomach than I do. I guess that what makes you "The Man".

John Ligons
AMT USA, LLC.

afterburner

My Feedback: (18)

Yeah, and the next time you are going to "sew" someone, make sure to use a strong thread.

Marty

Doctor J.

Hey Marty,
It would be good if all that was said on these forums was true! The fact is, it is not. If it would stop people from posting things false, we would sew. That fact is that in this type of environment it is hard to win even when the truth is on your side. By the way, by that time the damage is done and can not be measured.

Truth, I think the people on these forums deserve the truth and nothing but the truth.
Have a great day!

John Ligons
AMT USA, LLC.

Stallman

On the internet I see a couple of turbine brands, pushing either their thrust or their fuel economy (eassy to measure) over reliability (very difficult to measure) After seeing real world flying I can see why they do that!
Reliability meaning over the time you have the jet, how often can you fly it (or not), for any reason, be it breaking, blowing up shedding blades, burning up, seizing, unable to start it, unable to tweak the ECU, waiting for the turbine to get back from repairs etc. Last year I went to watch a lot of events to (try) to make buying decisions for my building partner and I, and I keep telling him I see a couple of brands mentioned here that burn (in the air or on the ground….or burn in the air then on the ground!) blow their blades off, have a gang of people trying to get them to start…then I see another brand flying all of the time and everyone with big smiles on their face.
Any time I ask about these other brands and their failures everyone is quick to say that all turbines have problems. Yeah, so how does that help? All car brands can break down but everyone knows some are much better than others.
Never seem to see reliability/availability discussed online.

J.F

C'mon then all the other manufacturers. Stand up and be counted. Lets see all manufacturers supplying standardised comparable figures to ensure customers receive exactly what is says on the tin...or better.

rhklenke

My Feedback: (24)

I have a Toyota Prius that is EPA rated at 60 MPG in the city. I have NEVER gotten even close to that. I do, however, consistently get better than the 44 MPG average that Consumer Reports rated the car at. Do I believe the EPA rating? Probably not - I have no idea how that was arrived at but I'm sure it involved a PERFECTLY tuned vehicle operated in a VERY specific way. I do know that I can get just about 50 MPG on the highway if I keep my foot out of it and I average 45 MPG on every tank.

Do I feel ripped off? NO! So far, its just like my JetCats - "tight" and well executed, dead nuts reliable, and I love filling the tank up with all of 8 gallons of gas every week and a half.

Go to any category of machinery you want to buy and there is some "standard" specification that is measured by each manufacturer in such a way that you really can't compare a number provided by a manufacturer against a number provided by another. If you could, then publications like Consumer Reports wouldn't exist (and that magazine does a booming business comparing across ranges of products). As Gordon aluded to, our comsumer reports are the guys in the tents next to us at the flyins.

I understand the desire for a "standard" rating system across turbines, but it ain't never going to happen - if it did, it would be the first time in recorded history - IMHO. Anybody who buys an engine solely on the manufacturer's numbers should read up on P.T. Barnum...

Bob

grbaker

My Feedback: (29)

But all cars are rated using the same testing process, which changes in the next year or so, to allow for more accurate results.

Turbine manufacturers can claim what ever they want to.

rhklenke

My Feedback: (24)

Which is again administered by the manufacturer's themselves and thus is always going to be suspect. The manufacturers also conduct government developed and specified crash testing and yet the Insurance Institute for Highway Safety, located right down the road, conducts its own version of those same tests and others to obtain what they consider a more reliable indication of a vehicle's crash worthness.

Independent testing and evaluation is the only way to get meaning full results for comparison. Its always been true and probably always will be IMHO.

Bob

Edgar Perez

My Feedback: (13)

The thread is about the importance of manufacturer meeting their claimed thrust/fuel specification, NOT what should be the driver for turbine brand selection
Claiming to be reliable or having good support is not an excuse for claiming false figures.

I think I will pay more attention to the GTBA competition results

wojtek

My Feedback: (73)

i thought the idea would be to have "unbiased" testing performed ??


Voy

jetpilot

My Feedback: (48)

It might not be a good idea for Ghost rider to test the turbines because he would just post the test results , and then outta habit just close the thread. J.K
Not but seriously its time for manufacturers to start making accurate thrust and fuel claims, include the engine test results with each turbine, and then have some third party test results like the GTBA. This would be so easy to set up at a jet event.
Its really hard to sift through the politcally correct post to determine any real data about an engine. It would also be REALLY nice if we were able to track and count flameouts and turbine failures of all brands.
Its also time for us end users to quit pretending like we never have any problems with the current turbines we are flying. I cant tell u how many times I have heard how awesome an engine brand is til after brands are switched and then you hear the real story. You ask anyone how they like their turbine they are currently using and they always tell you how much they love it, then you ask someone how they liked the same turbine they used to fly and they tell you how much of a piece of crap it was. Also people get their favorite brand turbine for the time being and seem to get amnesia about all the flameouts they have and all the money they've spent maintaining their turbine. People always say "go to the meets and see what people are flying and ask them for advise". All your going to get is very bias opinions, no real factual data.
Its really hard to come to any conclusions about any brand of turbines because the manufacturers arent accurate and the users are very bias. The only way to know currently how a turbine performs is to become the test dummy.
Now there are more choices then ever for turbine purchases, its time for factual data to be included when purchasing a new turbine.
There are alot of manufacturers claiming some very high thrust ratings and im curious how long these turbines last producing these thrust figures. I dont want a high performance turbine that blows up in 49 flights, just as much as I dont want an overated thrust turbine.
BLAH, BLAH, BLAH
Scott

Ehab

My Feedback: (44)

We get similar problems with sport bike data. Most companies "cherry pick" the newest and the latest bike and they give it to the mags for reviews. Sure enough, it scores very high in HP at the rear wheel. Few months later, riders have spent their $15,000 plus on these bikes to find out they are 10-14 hp DOWN from the mags...As a result I always dyno my bikes just to know what the real numbers are and guess what? it is always lower. So we go ahead and spend few hundred more $$ to increase the power back to advertised specs.

It may be a good idea to send a "dyno sheet" with every turbine sold. It is very easy to show thrust vs rpm, temp, humidity, and elevation...

By the way, I like all of my different turbines. They all have their pros and cons[8D]