Hi
Can someone explain to me why the Wren XL 200 has a bigger case diameter than its competitors yet puts out less max thrust at a higher RPM. My basic understanding of Turbine physics says that the bigger the mass flow of air then the more thrust. So the Wren with the bigger compressor should be out performing all of them. With the Wren competitors now pushing or exceeding 40lb thrust is the XL 200 in danger of being side lined?

M
( ps I am a big Wren fan I own one already and I will be purchasing another in the new year but the above question does bug me)

The XL200 has the bigger case diameter to allow for development. When we started to design the engine, several years ago, there was a reliability problem with some of the other 16kg engines and we were determined to make a reliable engine. We thought that perhaps the case size of some of the other engines was restrictive and was causing some of their problems, so we went for a larger diameter.

With regard to thrust, we were aiming at 16kg but we also wanted the engine to have good starting and throttle response, and although we could get the engine to give the required thrust it was not such a "happy engine" at 16 kg. So we settled for 15kg when we started selling the engines, and since we always try to tell the truth about thrust figures etc we didn't pretend it was doing 16kg.

The Wren team are constantly developing our engines, and all our engines have improved over the years. The 54 started out at 5kg, it has moved to 6.6kg for the standard 54 and 8kg for the SuperSport. The 44 started at 3.3 kg and is now 4.4 kg. Our expectation was that the XL would gradually become more powerful, in the same way. However, we've been very busy with other projects - notably the 44 Turboprop and helicopter - and so the expected development hasn't happened ... yet.

Certainly the engine has proved reliable, we haven't had any engine problems under warranty. There have been a couple of minor issues with pumps or ECUs which have been speedily replaced, but the XL200s have gone out to the customers and stayed there - as our engines usually do.

Sara Parish
Wren Turbines

On a previous thread someone felt it a shame that Wren, which he considered the small engine company, should bring out a bigger engine. Sara explained & I'm sure she will correct me if wrong, that lots of satisfied Wren owners (like yourself ) wanted to buy bigger engines but had no choice than to go elsewhere. Hence the XL 200.

I think we are obsesed by numbers but do not look at the overall picture. If those chinese turbines were the fabulous bargains they appear to be the flying fields would be over run with them. The low $ numbers say one thing, the reality, something completely different. Likewise with performance figures. What's more important is that the engine runs sweetly & is reliable. I'm sure the XL 200's put out AT LEAST the rated thrust all the time. The other manufacturer's quoted figures? - John.

Just wanted to put in my 2 cents. I have a dozen jet cat motors. I wanted to try a Wren on one of my euro sports.So I purchased a XL 200. I have been flying it a while. It has unlimited verticle thrust and has had no problems what so ever. Today at the field we down-loaded all the info from the motor to a lap top and reviewed. It is within all paramiters of operation. At this time the motor has 57 starts and 800 plus minutes on it with no troubles at all. I think this motor is every bit compairable to all the other motors of its class, and lets not forget reliable. My 2 Cents


Ronald R Long

You will see the XL 200 in action in Australia in September at Temora in my new Eurosport which is also being used as a test vehicle for some new avionics. It then goes back into my upgraded AW Hawk for the next JWM. Beautiful engine.

Regards, David Gladwin.

Mine is AWSOME I'm not sure on starts close to 100
and around 1300 mins on mine I had 3 flame outs
but it was because the deceleration rate was to low when the oat went up
now that i have change that I have had no problems what so ever

Hey Sara what will a 25hour inspection cost US please
I have Ron's number and will call I'm

Dose anyone have any experience with Rons turn around time
He is very helpful on the phone
but my 200 runs so well i hate to take it out

Ron is indeed vary helpful and you may be able to send your engine to him to get new bearings and have it returned fairly quick. My case, however it will take longer because of my wren 44. He said it because he has to send it to the factory to get rebalanced.

i will be in Midland somtime this week i would like to see you xl200 if posable and maybe fly!

You don't need to take it out. We don't have a 25 hour - or any other number - interval for service. We say "Listen to your engine and get used to how it usually sounds. The bearings will tell you when they are starting to wear, the sound changes and you will hear them grumble on spooldown." When the engine needs something, it will tell you. We firmly believe in the "if it ain't broke, don't fix it" philosophy.

Ron's here in the UK with us now, and has asked me to tell you that he has a spare XL200 which he will lend to good customers, if necessary, whilst their engine is with him. But he's not expecting to see your engine for a long time yet!

Sara Parish
Wren Turbines

I new there was a reason I bought a wren
Thats great thanks sara
Littlepiston
Come on down
I have to work saterday but Im free
all week call me
clint 432 528 9063

You might notice that the case is a little larger in diameter, but is shorter in length than some of the other turbines. It is similar in size to the AMT Pegasus, wider but shorter case, and this turbine has an excellent reputation for offering great thrust while putting little strain on the components. It is operating at lower speeds, temps, etc. The Wren XL appears to be designed to operate with the same theory, great output while almost loafing along, all the while being very dependable. It seems there is plenty of foom to grow.

Hi
Hopefully now that Wren have brought out there new 160 turbine then they may get round to developing it some.

M