I just order the Wren 44 Gold! Should I cancell the order and order the Wren 54? It seems nothing but problems with the Wren44. Its going in a Yellow Aircraft Stringray.
Thanks!

Moe , get the "44" if that size suits your needs. The problems we are having are caused by specific items within each installation. The Little "44" is an engineering marvel and allows you to keep overall weight down in the smaller airframes. Mine was operating perfectly untill I switched it into another plane. That tells you something. Back to the post, I tried Chas's suggestion and backflushed the filter.It seems to have worked. My accel delay is 25, deaccel delay 25, Stabilty delay @ 50. Ran the engine up very slowly to 190,000 and kept it there. It hovers around 190,500 and 189,500 but now it will hold at it's top speed rating. I throttled down and it runs above idle for a while before settling down to 56,000 were I have it set. Here's the problem, I still have some throttle travel left on the stick and when I push full up it goes beyond 190,000 and starts to power down. The ecu is trying to control the top speed. It looks like a calibration problem at this point. Will talk to Wren to see what they recommend. Doug

Hello Gaspar

Is this correct for the bypass? I just thought a diagram might help everone. I remember these from when my friend Larry was helping me build my kit KJ-66.

Great. I will get the 44! Does it come with everything to start it? (I know I will have to buy the Kerosene) And do I use propane/butane mix? I heard something about Powermax. Where can I get Powermax? thanks all!

I've had a number of potential customers speak to me because they think that there are problems with the 44s. I'd like to put it into perspective: there appear to be 3 people on this thread with problems and that is less than 1% of MW44 owners, so to the best of my knowledge 99% of MW44 owners are NOT having problems! The problems are all slightly different too, but I think it is worth re-posting some information from Mike Murphy which is already on the "Summertime Blues" thread.

"There is a definite link between climate and problems with the MW44s flaming out on acceleration. This is due to surge which is made worse by high ambient temperatures. Mike Murphy says that the remedy is to increase the acceleration delay to slow the rate of acceleration slightly. Without having a climatic test cell (and only Rolls Royce have one of those!) we can't anticipate what settings are going to be needed. We have had engines tested in warmer climates and David Gladwin has had no problems in Australia at 40 degrees C, but all engines are different and the smaller ones are more sensitive, so some will be affected more than others. All engines are tested thoroughly before they leave here and only the ones which perform well are sold, but we cannot tell how an individual engine will react to high ambient temperatures.

We have recently discovered that another cause of flameouts can be the position of the tailpipe. Two years ago we recommended 10mm from the end of the exhaust, but have discovered that with the higher-power 44s a larger gap of 25-30mm is needed. "

If you have problems, PLEASE speak directly to us straight away. I love the way that people on RCU help each other out, but the MW44 is different from the larger engines and solutions which apply to them don't always work on this tiny engine, so well-meant suggestions can sometimes make things worse. We are the experts - Mike designed the 44 and the team here are working with the engines all the time. We know it well enough to have been able to increase the thrust by an amazing 25% in the last few months ... please trust us to help you!

Sara Parish
Wren Turbines

wow rolls royce
but a small engine needs a really tiny little testcell
and a old choar fire to make heat and some steam for the moisture in the air (tea pot)
i bet it is cheaper then the RR one......[8D]

one thing is for sure you never here anyone from denmark or norway or sweden complain about thrust or problems
they are freezing there! good for thrust

Regards "master cookie eater" Sandor

high ambient temperatures + humidity

Alabama (Arm pit of the world)

Johnny

Posted on the L39 thread, thought I'd copy across here- just in case someone actually uses the search function!