Hi all,

Will speak to wren on monday about this, but thought id pick others brains as i dont think this is a engine problem.

Ive got a brand new Wren SS. Ive had 7 flights now. First 4 were fine. But on the last three the spool up time in the air from idle to full is over 10s, sometimes 12s.

On the ground, its about 6s. But on take off today , just seemed a bit longer.

Ive noticed that the spool time is probably longer in turns than straight and level, but this pattern could not be consistently repeated.

My boomerang previously had a Wren 54 mk2, which would pull 2/3 of the fuel of the SS at full throtttle. There were no issues there with my fuel setup.

I do have the UAT at the front of the avionics bay in the boomerang, and the fuel pump at the rear. That 25cm ( or 8-9 inches ) from the Main tank to the UAT and then the same again back to the pump.

This arrangement worked with a less thirsty engine, but could this be unsuitable for the SS?

I have spoke to wren a few weeks ago after the 2 first odd flights and they suggested looking at where the rpm lead was going in case it was getting interference, distorting the rpm signal. Ill post pics of my setup tomorrow.
If that failed to help, the next suggestion was to return the ECU to get its data checked. Id obviously like to explore other options before grounding the airframe.


Could the distance from main tank to UAT, and back to pump be respnsible, especially with increased G forces in the air??
Seems strange it worked great first 4 flights, but now is misbehaving when i havent changed anything.



( Setup 2l main tank, large tygon tube, jetronic clunk and BVM UAT.)





It seems st