Status Change

[Dorsal]

Went up, came down, everything is good.
Only concern is that after about 20min the fuel pressure drifted up to ~5.5-6 psi, any thoughts?
Other than that the first flight was uneventfull and the plane flew beautifully.
Thanks to Mo for showing me his project 2.5 years ago, Andrew for helping me with the brown gunk, CDE2Fly for getting me some stick time and of course Deb and John and all of you who help with advice along the way.

[Dick B in KY]

Congrats Dorsal, You have crossed over to the other side, building is behind you and fun and adventure are ahead. Hope all goes well with your phase 1.
Again congratulations!!!!

Dick B

[akarmy]

Congrats! That's great news!

As for fuel pressure, I don't have any direct experience. I actually removed the pressure gauge from mine as it was always fluxing up and down, high and low while the engine continues to run smooth hour after hour. In a basic gravity feed system it should be mostly self managing.

[Dave S]

Dorsal,

Congrats on the first flight! Actually "status change" cannot do justice to that kitfox grin! You did it!.

Anyway - a couple ideas on the fuel pressure deal.

1) I do not know what kind of fuel pressure gauge you have; but, it is a classical deal with any gauge system that the system is going to give you a number - unless the gauge has been calibrated - remember that the number it is displaying may or may not be right. There are always manufacturing and installation variations, and, murphy's ghost guarantees that the errors will stack, not cancel.

2) Might be a good thing to record your engine serial number - and the fuel pump part number and cross check it with the Rotax advisories - I do recall that there was a group of roptax roduction fuel pumps that had high pressure issues - if your pump is one of them - that might be the answer.

3) If your gauge is any kind of resistance/electric type and not a direct reading gauge - temperature can play a role in the indicated reading compared to the calibrated reading. (or words to that effect)

4) If your gauge is any kind of resistance/electric type and not a direct reading gauge- there is potential for resistance points at connectors which can bias the reading.

5) If your gauge is a direct reading type - any error, if it exists, will likely be a percentage of scale

6) In any case - if the high reading is associated with rough running (like rich mixture) - I'd tend to believe the gauge.

BTW - are you going to get your plane on John's website under completions????

Sincerely,

Dave S
Kitfox 7 Trigear
912ULS warp

[Dorsal]

This is a Pic of my fuel distribution setup, it gets quite toasty so I have wrapped the block, the pressure sender and the flow meter in some heat shield silver coated fabric stuff. Will let you know if this helps, won't fly again till Tuesday (good name for a band). As with Andy my engine ran fine, not sure if this is the sender getting hot or actual hight pressure because the block is getting hot (or other). This may be a classic case of the Heisenberg principal where I am causing a problem by my attempt to observe if there is a problem.

[DesertFox4]

Dorsal, first off Congrats! Building is fun but flying is always better.

Just thinking about your high fuel pressure numbers.

I'll assume you did a fuel flow test before first flight and found fuel quantity delivery to both carbs exceeding maximum demand at full power setting by a good percentage.

My understanding is the Bing carbs will flood and not operate properly if hit with too much fuel pressure. I'm also thinking you have a error in the information from your sensor. The carbs will let you know with out doubt when they receive too much fuel. 5.5 to 6 psi should make the carbs flood and the engine to stumble or worse. We've always been told not to run an additional fuel pump if it delivers at a pressure over 4 psi. Some have tried with less than enjoyable results. If the engine is operating well and for extended periods throughout it's full rpm range and throughout all attitudes, you may be chasing phantoms.

Lots of information in the cockpit is at first glance logical and desirable to most pilots. However if a not so necessary information provider is untrustworthy it will do nothing but cause distraction and create anxiety. I'm not saying ignorance is bliss but I'll bet many of us have spent nervous time in flight, monitoring a gauge intently that was sending false information.

Our once simple little airplanes are evolving into complicated creatures. Unfortunately consequences come with complication.

What ever indications you get Dorsal from whatever instruments please remember to fly the airplane above all else. You are officially a test pilot. Enjoy the process.
Congrats. again.

[Maurice]

Dorsal, congratulations. I can't wait to see your writeup and photos as KOTM. I enjoyed your visit with your two sons 2 1/2 years ago, my visit to you and your airplane to get some measurements to reassure myself, your offer to lend me your hingemate, and your many thoughtful posts.
Maurice

[Andrew G]

I missed this post... as the title was way too humble a title for the accomplishment....

Great work Dorsal. I don't know the break-in rules re distance from the FBO, but I hope that soon you can fly over my house

Congratulations...

Andrew

[cap01]

dorsal ,congrats , certainly is a big event , now the fun begins . how did your inspection go ?

[Dorsal]

Inspection? what inspection ........
It went very well, couple of hours of poking and questions but all in all the DAR was quite satisfied with the work. The difficult part was getting agreement with the FSDO on the flight test are and ops limits, took 2-3 weeks of challenging communication trying to figure what they wanted. My DAR is accountable to one FSDO but my flight test area is in another, good times