First Flight of N25SX

[Dwbbrown]

I flew my Sonex B Model serial#016 on 5th of May 2022. First few flights the left wing was heavy, took several adjustments of left flap to get it close.
UL Power 350i. Sensenich wood prop gives amazing performance.

[BRS]

Congratulations!

Can you tell us what you think about the UL engine?

[Bryan Cotton]

Congrats! Welcome to the forum! Where are you?

[Dwbbrown]

My home town is Ozark, Arkansas, but I live South of there and have my hangar located about 5 miles from home at a grass strip, ETNA 2AR1. I now have 20 hours on the airplane and it flies like a dream. The UL engine performs really well, but I did have some cooling issues with the fuel pumps resulting in a vapor lock and and a force landing on the 4th flight. I was at the airport and the landing was uneventful. I have worked on a cooling duct with forced air over the fuel pumps and now have temperature monitoring and everything is normal, but will do more testing when the weather gets warmer.

[WaiexN143NM]

Hi d brown,
Your plane looks excellent , have fun! be safe! keep us updated.


Cheers!

WaiexN143NM
Michael


also tell us about your little cowl flaps ahead of the B side vents.

[Dwbbrown]

When the engine was breaking in it seemed to produce a lot more heat under the cowl and the CHTs were running high and I had the fuel pump problem, so I added the the louver and riveted on both sides. This helped with all problems. I also added two smaller ones on the bottom of the cowl near the hinge pin. I don't think the fuel pumps were generating the heat that caused the problem but the high temps under the cowl. UL's instructions for mounting the fuel pumps have prefuel pump filters and an after fuel pump filter. The Prefilter is gravity feed which I believe the excess heat caused the vapor lock.