Original Posted By: "Charles N. Campbell"
Sorry, I was having trouble interacting with the Matronics site last night. Here'sthe original message that the photos above are a follow-up to:I have a new movie up in which I'm testing a trim system comprised of a bungeecord and a clothesline tightener:
https://www.youtube.com/watch?v=xfUMSuEMEwc The movie doesn't show the trim system (I will post pictures later if it reallyworks out). What the movie shows is that the system will hold my Piet right at55 mph from abeam the numbers to roll out, with no input from me (other thana short shot of throttle to clear the fence!). This was a good thing becausethe sun was in my eyes and I had very little sight down the runway. The trim systemwas sort of "land-o-matic" So, my Piet is fairly easily trimmed for downwind-base-final-landing. I played around with it at altitude, and even if I don't use the tightener "valve"to release the bungee, I can still power up as though to do a go round. Itdoes require a hefty amount of forward pressure to overcome the bungee, though.Obviously the idea is to pull the tightener valve to relieve bungee tensionwhen it's not needed. I also used the system to play around in slow flight, and spent some time doing30 degree banked lazy eights and 360s at 45-50 mph. Rock steady (though thiswas in the evening, so there were no up/downdrafts and little wind). The tightener was cheap (under $5 from Ace Hardware) and looks like this:
http://farm8.staticflickr.com/7131/7559 ... 1e5594.jpg Imagine the line on the left being a bungee cord hooking to the rear of the controlstick torque tube. On the right, the tightener U-ring is attached to thecontrol stick just below the control stick hand grip instead of to the eyeboltin the photo. If you want to trim for "up", pull the bungee cord that sticksout of the tightener valve. This stretches the bungee and locks it into that length.The bungee tension holds the stick back. If you want to release that trim,pull on the valve (it's mouth is shaped like a trumpet or trombone bell).It's clunky to use right now, so I may optimize it a bit. However, even as it is,it's meets my main goal of trimming for the pattern.Read this topic online here:
http://forums.matronics.com/viewtopic.p ... ______Date: Sun, 9 Nov 2014 18:30:17 -0500Subject: Re: Pietenpol-List: A Great Film Showing Grassroots Aviation
