Pietenpol-List: Piet Component Weights

[matronics]

Original Posted By: Jack Phillips
The following may be of interest to the group. I found it in old files,Mike B Piet N687MB (Mr Sam)----------------Hello Gang,Quite a few years ago I prepared this for our EAA Chapter newsletter.It may be of interest to those who are building Pietenpols. All weightsare given to the nearest quarter pound. These figures apply to C-FARH,a Pietenpol built by a friend in 1975. He used my jigs and this a/c is asister to mine. It is powered by a Continental A65 - 8 and has a 3-piecewing.20COMPONENT UNCOVERED COVERED20-----------Wing panel (each) 50.5 63.5C/Section ------ 22.5Rudder 3.5 4.5Vert. fin 1.5 2.25Horiz. stab. 6.0 8.75Elevator (each) 3.0 4.5Aileron (each) 4.0 5.5------------The total weight of the doped polyester fabric cover for the above20components was 36.5 pounds. The estimated weight of the fuse-lage covering was about 8 pounds, giving the total weight of the20cover at about 45 pounds. This could have been reduced a bit byusing a lighter grade of fabric.The weight of the fuselage and main landing gear was not available.The combined weight of lift and jury struts, strut bracing wires,tail20bracing wires, hardware and fittings was about 30 pounds.The tailwheel assembly weighed 6.5 pounds and is the A-frame yoketype with a coiled compression spring. The tailwheel itself was some-what lighter than the Scott 6" tailwheel used on many lightplanes.-------------------------- SUGGESTIONS FOR REDUCING WEIGHT 1. Routed spars could save 13 -15 lbs. overall. This a/c used solid20 spars (Sitka spruce, unrouted).2. A single piece wing according to the plans would eliminate a lot20 of hardware and save about 15 lbs. (Ref. BHP himself).3. A minimum amount of dope and paint will save some weight, but20 not very much when the entire cover weighs only 45 pounds. Keep20 the cover light and flexible with the weave of the fabric still visible in the finish.4. Avoid heavy seat cushions, keep instruments small and few in num- ber. Use a lightweight fire extinguisher.5. Use a wooden propeller instead of a metal one and save about 10 lb. Avoid oversize tires (6.00 - 6 or 7.00 - 6, 4 ply rating, are OK).Old20 C-FARH uses 8.00 - 4 Cub wheels, brakes and tires.6. Do not use an electrical system with starter, etc. unless you are prepared to pay the penalty in performance.7. Use lightweight magnetos such as Slick and save several pounds.A- void fibreglas cowlings unless they are quite thin and well-made.Both20 C-FARH and CF-AUN (my a/c) use aluminum sheet cowlings. Very20 light and simple.8. Follow the plans! Pietenpols are perhaps overbuilt and careful engineer- ing could pare some weight from the structure, but this could compro- mise durability for pasture flying. The tail group is as light as itis pos- sible to make it. Some fittings should be redesigned to current engineer- ing standards, but that is about all one can recommend. This neednot add any appreciable amount of weight.The Pietenpol airplane, as designed, is a marvel of practicality and simp-licity that is difficult to improve upon. One can preserve this by keeping it20light. Watch the ounces and the pounds will be taken care of automatically. Bill Stout (who designed the Ford Trimotor) said itbest:20 "SIMPLICATE AND ADD LIGHTNESS!"Graham________________________________________________________________________________Date: Sun, 18 Mar 2001 19:43:59 -0500

[matronics]

Original Posted By: Don Mosher