Original Posted By: grhans(at)freenet.edmonton.ab.ca
The following is an excerpt from "EAA Aircraft Building Techniques": "If your spruce ship weighs, say 800 lbs. empty you have probablyaround 100-150 lbs. of wood in it. With fir your ship would pick up25-35 lbs more, which isn't very much, all things considered." (Not mywords - just a quote). However, based on the information contained in this excellent guide, I have substituted fir in the seat framing, ailerons and a few other bits and pieces here and there. I do not remember the prices I paid at the time, but definitely cheaper than spruce and due to the smaller individual sizes I was able to cut out excellent pieces as required. By smaller I don't mean reduced dimensions I left everything sized as per plan. Working with fir is a bit more difficult, but when I "cut off one piece twice to find it still an inch too short" it was relatively painless ($). (By the way I'm sure that was the only "errant" cut I madeduring process Need any fir toothpicks? Gary________________________________________________________________________________
Original Posted By: jimvan1(at)juno.com
Hello Gary,I have been following the discussion regarding spruce versus fir in thePietenpol airplanes. For what it is worth, I recorded the weights ofvarious components of two Pietenpols: my own (CF- AUN built in 1970) and my friend, Roy Wadson's (C-FARH built in 1975). I shall place AUN'sweights in brackets and ARH's without brackets.* NOTE: Covered weight of wing panel for CF-AUN includes aileron, also covered.CF-AUN was covered with Grade A cotton which was heavier than the poly-ester fabric used on C-FARH.AUN'S spars are of laminated fir to form an I-Beam section identical tothe routed section shown in the Pietenpol plans. ARH's spars are of Sitkaspruce, unrouted (4 3/4 inches by 1 inch...the basic unrouted dimension).The rest of AUN's structure is mainly of spruce while ARH employs spruceexclusively. AUN is the the lighter of the two and originally had an empty weight of645 lbs with a Continental A65 and a 6 foot wooden propeller and Grade Acotton cover, hand- rubbed. It has since been recovered with polyesterfabric and has a "utility" finish using less dope. This, together with thesubstitution of an ultra light tailwheel in place of the old 6 inch Scott,has resulted in a weight saving of 15 lbs.! I now weighs 630 lbs dry witha C85-8 engine.Icannot recall ARH's weight, but think it is in the neighbourhood of 665lbs. dry. Frankly, I cannot account for the difference between the twobecause they were built from the same jigs and are very similar. ARH'slanding gear may be a bit heavier and there must be a few extra poundslurking here and there...but I don't know where.If I were to build another Pietenpol, it would be under 600 lbs drybecause I would use aluminum ribs, leading edge and trailing edge, lightercovering and could save some weight in fittings, struts, etc. A one-piecewing would save close to 15 lbs. alsoBill Stout, designer of the Ford Trimotor, is reported to have said:"Simplicate and add Lightness!"Cheers to all, Graham Hansen________________________________________________________________________________
Original Posted By: "Cy Galley"
All, Thanks for the responses. This list is still the best piet building resource. Also, I'm glad that Ken brought up the article in Experimenter. Really enjoyed reading about Steve's build! I understand there are more Piet articles to come in either Experimenter or SA.Joe________________________________________________________________________________
Need any fir toothpicks? Gary________________________________________________________________________________