ULF-1 Discussion Archive
Anonymous static archive of the former Mailman list
Anonymous static archive of the former Mailman list
Re: [ULF-1] florida or usa builders.
Hi Alex, We are using 1/2" and 3/4" STYROFOAM Brand Residential Sheathing made by DOW. It has a minimum density of 1.30 pounds per cubic foot (pcf). It is blue colored. We cut out parts using a computer controlled cnc milling machine after scanning and plotting the loft diagrams by computer. We did static load testing to destruction using a hydraulic jack and a bathroom scale as outlined in the the Jan.-Feb. and March-April 1999 articles in Sailplane Builder journal article by Ian Lea. (Google "foam aircraft rib" to find the article.) We cut out rib #2 from the wing loft drawings in both 1/2" and 3/4" blue foam (as above) and glued 3/32" spruce cap strips top and bottom, 1/2" and 3/4" wide respectively, with T-88 structural epoxy. We cut the cap srtips so they would overhang about 2" off the front edges and glued the ribs onto a mock-up spar glueing down the cap strips on the top and bottom of the spar to act like gussets. The 3/4" rib weighed 4.2 oz. and failed at 135 pounds pressure. The 1/2" rib weighed 3.4 oz. and failed at 120 pounds. We determined the foam ribs weighed less than the plans stick built ribs and were much stronger. So, based on these findings, we have decided to use 1/2" foam and 1/2" x 3/32" spruce cap strips on all ribs and stiffeners except wing ribs #1 and 2 where we will use 3/4" ribs and 3/4" x 3/32" cap strips. Doing this will provide a lighter and stronger airframe and really speed up construction--a win, win, win! Best regards, Member 72 Serial No. 343 E ---- Member 91 <[email]> wrote: > Hi! Nice to meet you! :) It is very interesting to use foam. Can I ask you about foam type what kind of test you did? is it static load or some dynamic tests? Thank you! --------------- Alex > Hi Paul, > We are a ULF-1 build group in Mooresville, NC. About a dozen > members of EAA Chapter 309 (Charlotte, NC) meet for 3 hours every > Tues. night to work on my ULF-1 in my hangar. I work on it every > day in between "Build Nights". We began construction with the long > work benches in January and have built all 6 tail spars. We are > currently framing up the fin and rudder. We did some engineering > tests and determined using 1/2" blue foam ribs capped with 3/23" > spruce cap strips would make ribs that are lighter and stronger than > those made out of spruce sticks and ply--and speed up construction > immensely. I hope you decide to build one. The build is a bit > tedious, much like a large model aircraft, but fun overall. > Best regards, > Member 72 > ---- Member 90 <[email]> wrote: >> hello; i am building a pietenpol aircraft (Member 60 and fabric two place tail dragger). having so much fun with it, thought it would be cool to also build a ulf-1. I also fly hang gliders. just wanted to hear what actual builders/flyers have to say about the aircraft. anyone in florida or USA? thanks; Paul >> >> Sent from my iPhone >> _______________________________________________ >> ULF-1 discussion list -- [email] >> >> Subscribe, Unsubscribe, Preferences, List information: >> http://lists.ulf-1.com/listinfo.cgi/ulf-1-ulf-1.com > _______________________________________________ > ULF-1 discussion list -- [email] > Subscribe, Unsubscribe, Preferences, List information: > http://lists.ulf-1.com/listinfo.cgi/ulf-1-ulf-1.com -- С уважением, Alex mailto:[redacted] _______________________________________________ ULF-1 discussion list -- [email] Subscribe, Unsubscribe, Preferences, List information: http://lists.ulf-1.com/listinfo.cgi/ulf-1-ulf-1.com