Test Period - Performance Limitations

[Tomfox]

I am confused about establishing performance limits in the test period. I am under the Amateur Built Experimental catagory.

Do I need to test the limits of everything, such as weight (1320 lbs) and CG limits and that serves as the limits on my aircraft, or can I use the established limits for an SS7 for CG? I find it difficult to load my plane to get to the negative 16.0 inch CG limit - too much load in the cargo bay.

For instance - I am now loaded with 60 lbs of cargo at the center of the cargo bay, full fuel and the remainder of the 1320 lbs in the passenger seat. This give me negative 14.5" of CG. What do i use in the limitations that I establish for the plane.

Thanks
Tom Livermore
N516DA SS7 Rotax 912ULS

[Flybyjim]

Hi Tom,

I have built 3 other planes before this Kitfox SS7 that I am building now and yes, you should test your plane in as many configurations as possible to know YOUR plane, not the spec's printed by someone else. Each plane comes out a bit different, just take your time with loading the plane to full aft weight. I fly my planes with a close to center CG as possible for the first 10 hours than start working with load going to the most forward and than work to the aft CG. I used 50 lb bags of horse feed to load up the plane as needed.
You need 40 hours anyway so make good use of the time. I added VG's on my Rans S-7 at 20 hours and was blown away by the results, stall went down into the low 30's with full flaps.

Have fun with the journey

[avidflyer]

The FAA has an advisory circular that makes for a good read and guide for flight testing. AC 90-89A Jim Chuk
https://www.faa.gov/documentlibrary/media/advisory_circular/ac%2090-89a.pdf

[jiott]

I also pretty much patterned my 40 hours testing after the FAA AC 90-89A.
Also, a personal opinion comment is that the Kitfox is a well engineered and proven design with thousands flying. If you build your kit by the book without any mods that affect the flying/control characteristics, then your airplane will fly like the factory specs say it will. IMHO the 40 hour test phase is more of a formality to get YOU familiar with your airplane performance envelope and to uncover any major errors you may have made in the build. I wouldn't sweat too much in trying to wring out every last extreme corner of the envelope if everything else is falling within expected parameters. I think its overstated to say that every kit built airplane is different and imply that it must be tested as if it were a new design. Sure there will be minor differences that require some tweaking with wing washout and trimming, etc. but this is not really what the 40 hour testing is for. I personally enjoyed being a "test pilot" and tried to do most of what is in the FAA 90-89A but really did not feel it was absolutely necessary. This is my own opinion to take for what it is worth, and I fully expect to get some disagreement.

[efwd]

Sport Aviation OCT 2016 article "Flight Test Safety on the Upswing" is a pretty good article to read regarding the EAA's efforts at addressing the 40hr flight test. In my head Ive been thinking of the day I begin that phase and am curious as to how I can do it as safely and professionally as possible. The careers of test pilots intrigues me. I look forward to EAAs development of the XP3 (Experimental Plane and Pilot Program) guidance. I doubt that its going to be established with the FAA by the time I am in phase one (my ambitious timeline to completion, power of positive thinking) and save me from the 40hr requirement but I am most excited for a test schedule that I can use that will establish data that is needed to know my aircraft totally.
Eddie

[n85ae]

If you build it to specs, then it will fly like all the rest. I'd suggest Fly most of
your test flights over airports, or big open fields. Your biggest concern with a
new Kitfox will be where to land if the engine quits.

Jeff