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Repairing Deteriorated Fabric With Fiberglass Cloth

Roy M. Prine At this stage of your planning it is important that you have a Early in 1955, a Kansas City, layout table to serve as a draw- Missouri Fixed Base Operator ing board. On your board you approached the C. A. A. with now can start actual design the intriguing idea of repairing work. The following steps are and reinforcing deteriorated air- recognized to be an excellent ap- craft fabric with Fiberglass proach in any design work, and cloth. The method to be used I would suggest that you plan was simply sheets of the glass your drawings according to the cloth on the fabric, then secure following method. or bond them to the underlying (A) Layout drawings. —This fabric with either a resin or air- is a general drawing of a section craft dope and in all probability of the airplane in which the lay- the aircraft would not have to be out of various parts is arranged disassembled, a distinct advan- clearly understood. If your and from which detail drawings tage. Design Preparation knowledge is limited somewhat of these parts can be made to Believing that the idea had in regard to the aforementioned fit the completed structure. merit and since it is recognized Stanley "Prop" Dzik (B) Installation drawing. -- questions, I would like to con- that the majority of the fabric This drawing shows groups of vey to you the avenues to follow covered small aircraft have fa- Designing an aircraft of your that will enable you to carry out parts or assemblies which com- bric that is marginal or even own concept, whether you in- your design work with less prise a major unit of an airplane sub-marginal in strength, and tend to use it for just plain plea- doubt. structure such as the realizing that within the next sure flying or acrobatic work, installation' drawing which two years the figure will rapidly First I would suggest that you shows the location of all fixed can relatively be a simple under- visit your local library, and ac- increase, the Operator was ad- taking, or it can ultimately re- points in the fuselage. vised to go ahead and every as- quire several basic aeronautical (C) Assembly drawings. —This sult in discouragement. books on aircraft engineering. sistance possible would be given I would like to aim this dis- drawing shows the assembly of him. If your local library 'does not two or more parts into a unit. cussion to those who contem- have the books you're interested Since there was no informa- plate designing their own air- (D) Detail drawings. —This tion or knowledge available on in, then ask the librarian for is a drawing of a separate part craft, and to those that gave up addresses of publishers or the the subject, it became necessary the idea. To these individuals which will later be assembled to set up an experimental pro- source that you can contact for to other parts. I would like to direct some per- a list of books you can pur- gram to determine methods of tinent advice regarding the pre- (E) Rework drawings. —When accomplishment, to evaluate the chase. I would also suggest that it is desirable to rework a part requisities of basic design, be- you write to the Superintendent practicability and airworthiness so that it may be used, this draw- fore attempting to build their of Documents, U.S. Government qualities of each method devel- aircraft. ing is prepared to show how such oped and to accomplish this cer- Printing Office, Washington 25, rework operations can be car- The first thought in mind D. C., and ask for a list of C.A.A. tain standards and criteria were would be to make a 3-view plan ried out. set up as follows: Technical Manuals on aircraft I have only highlighted and configuration drawing of the construction and maintenance, There should be no apparent touched on the most important type of aircraft to be desired. for example, C.A.M. #1, 8, and conflict with C.A.R. parts 3 and factors that are necessary to car- At this point you believe you 18. After you have obtained 4. All material, technique, pro- ry out a well planned project. really have accomplished some- these books and manuals, I sug- cesses, and workmanship must If you follow the suggestions as thing. All that you have now is gest that you study all phases be compatible with C.A.M. - 18 a "pretty" picture of an air- outlined in this discussion you requirements. There must be on aircraft design. I do not will realize that the end result plane, and in most cases you've mean that you glance or page no adverse effect upon the struc- will be most gratifying in respect done just that. How much do through the technical matter, tural integrity or flight charac- that you will save yourself con- I know about but apply some serious studying, teristics of the aircraft. siderable time, effort, expense (1) aircraft materials and their even if it means burning the During the next few months, and most of all "grief". application in aircraft design? midnight oil. many methods and processes (2) "An" aircraft hardware In conclusion may I remind Let's assume that now, after were tried and evaluated using specifications related to type, you that it takes a little mental and plastic resins you have devoted much time in size and quality? sweat to find the approved short- until one process appeared to (3) weight and balance? the course of study, some of the cut. puzzling questions you had prior meet the criteria and standards (4) aircraft standards and pro- Editors Note: —We are pleased set up. Also the process was to this time, are now answered. cedures? to have published "Prop" Dzik's easy to understand and use, no (5) C.A.A. rules and regula- If your design involves con- "Design Preparation". E.A.A. special equipment or tools would tions governing amateur built siderable (a) sheet metal work, Headquarters has a tremendous be necessary, and installations aircraft? (b) steel tubing, (c) or wood- flow? of correspondence from could be made by any certifi- The outlook now seems a trifle working design, it would be ad- members to answer relative cated mechanic if instructions complicated, but let me assure viseable for you to purchase a simple technical questions. An- were followed. you that is not the case at all. set of plans that are of compar- swers to those questions can be During the experimental pro- There is no mystery involved able design to your own from acquired by following the advice gram, invaluable assistance and in designing your own aircraft. a material standpoint. You will in the "Design Preparation" ar- advice was given by the person- With the proper approach in find that the plans will be an ticle, thus helping reduce the nel of Owens-Corning Fiber- planning, each step must be invaluable reference for gui- load on E.A.A.'s correspondence glass Corp., who manufacture carefully studied, analyzed, and dance. work. See Fiberglass on Page 13 13

Continued from Page 4 the basic glass material and Hess-Goldsmith and Co.. Inc., who manufacture the glass clo'h. Many types and grades of glas~ cloth and bonding agents were tried during the experimentrl trial until one type was found that had the desired qualities and most nearly approached grade A. aircraft fabric but was considerably stronger in both directions. The aircraft dope bonding process was approved in July 1955 and a few months la- ter the Epoxy resin bonding pro- cess was developed and approv- ed. Each process has distinct advantages and disadvantages but if both processes and meth- ods are combined at a slight in- it created too much turbulence. crease in labor and material, the industry. The Parasol Champ! A smaller windshield is being advantages of both methods can A few of the specific questions made, while it is presently being be had. for which specific answers must The July, 1955 issue featured flown without any windsheld The aircraft selected for the be obtained are as follows: an Aeronca "Champion" which at all. original experiment was an Aer- a. If aircraft dope, plastics or was modified to a parasol con- The wing tips were also re- onca 7 A C with deteriorated resins are used as a bonding figuration. The parasol effect moved, and tip plates were then fabric which strip tested be- agent, is the bond of sufficient was achieved by cutting the added. tween 35 - 38 lbs., the structure strength? fuselage back down, and remov- James E. Tyndall of 5606 being satisfactory and airwor- b. At what rate will this bond ing the cabin from the fuselage, Patterson Avenue in Richmond, thy. After completion of the ex- deteriorate? still retaining the wing support Virginia, did this modification periment, the reinforced fabric c. Does the Fiberglass cloth structure, rather than construct on his Aeronca, for the total was again strip tested and show- and aircraft laminate have suf- new cabane mounts. cost amounting to $550.00, which ed a tensile strength of 165 lbs. ficient tear resistance after being The standard "Champion" included the original airplane. in one direction and 125 in the finished? windshield was trimmed off a The rate of climb and speed are opposite direction. The estima- d. When applied over old fa- little, but had to be after the about the same as any other ted weight increase was approx- bric, can Fiberglass cloth be so first test flight last fall, because "Champion", but it handles imately 25-30 lbs. but should de- attached that after the under- much better, according to Tyn- crease as the wet dope dries. lying fabric has completely de- dall. He believes that it has Later experimental work using teriorated, a satisfactory attach- great possibilities as a crop-dust- an Epoxy resin indicated that the ment to the primary structure er or sprayer. Epoxy resin method may have and the wing ribs be retained? However, Tyndall isn't inter- many advantages over the air- e. Will the Fiberglass cloth ested in proving that possibility, craft dope as a bonding agent and fabric laminate have suf- but is looking forward to build- ing a "Honey Bee", as soon as and may likely replace the dope ficient structural integrity when Continued from Page 9 bonding method when the ma- operated in turbulent air or the opportunity presents itself. terial is more readily obtained acrobatically in or under ex- sturdy plaster and hemp fiber Leo J. Kohn and understood. treme temperature conditions feet on them. After these are The original experiment was and rapid temperature changes? set inspect the inside surfaces completed in July 1955 and con- To assist the industry in ob- and make any necessary repairs. News Note ditionally approved by the CAA taining basic information on When dry give it the dope treat- in the standard category, the these two processes, The Avia- ment then wax it, and you are Hal Sanders and Bill Roden- conditions being that evaluation tion Glass Cloth Services, 1421 all set to make as many cowlings berg are quite busy these days tests and their results to be re- E. 25th Avenue, North Kansas as you wish in these molds, wax- restoring a Heath Parasol. The ported each 90 days for approx- City, Missouri has prepared a ing between each set. After you ship has a Continental A-40 en- imately 1 year. This was due kit of instructions and informa- and an assistant have done the gine and prop taken from an old to the fact that it was recog- tion at a nominal charge which laminating, lay in a sheet of pol- Taylorcraft, as well as the wing nized from the results of the includes free consultation ser- yvinyl film, and sand bag it un- which were cut down. experiment that the problems vice on application problems. til it sets. The gear is from the T-craft also, of repairing and reinforcing de- Glass cloth covering of the Now break off the plaster but has been cut down 3 inches teriorated aircraft fabric had complete aircraft offers wonder- from the engine, and sweep all and the 6 x 6 wheels were retain- several aspects not fully resolv- ful possibilities to the experi- the plaster from the shop. ed. ed, and until such time as the menter as tremendous strength When you unwrap your engine More details on this ship will following questions were an- with extreme lightness can be it will look as good as ever. appear in a future issue. Mean- swered and the qualities of the readily obtained with only a Hard work? Yes, indeed. But while any members in the area Fiberglass cloth resin process fraction of the cost and no spe- no more than forming an alum- are invited to drop in for a visit. was proven by some closely ob- cial technique or special tools inum cowl and it requires less The ship is located in a quon- served tests, it would not be pos- are required. skill and equipment. If you re- set hut on the northwest corner sible for the CAA to grajnt blan- Editors note: The writer is a inforce it properly, it will last of Centinela and Major Streets, ket approval of any procesSf'pre- C.A.A. Aviation Safety longer, make a quieter plane, Culver City, Calif. Hal and Bill pare CAM material or issue Agent who has resigned to go hold paint better and will not are usually there on Monday any specific information to the into business. suffer from fatigue cracking. evenings. PAGE 10 EXPERIMENTER NOVEMBER, 1956 and after proper positioning through the fiberglas. Care must then. be used to produce a smooth Repairing Deteriorated Aircraft 6. Start about the center of the hole through the covering and panel, using a soft brush, brush the cord must be heavily waxed. on Butyrate thinner carefully 2. Secure the fiberglas to the Fabric With Fiberglas Cloth working outward from the cen- with a 4 PK screw and plas- ter. Extreme caution must be tic washer in lieu of additional produced by several companies used on the first brush applica- rib stitching. This method will PART 2 |i and sold under trade names, the tion at the center, as fiberglas require prior CAA approval, as (Continued from June, 1956) original experimental work was will slip readily, but after the the PK method of securing fa- performed using Shell Chemical thinner is applied, the drying ac- bric to ribs has not received Prepared by Roy M. Prine "Epon 815, catalyst DIETHY- tion is so rapid that the cloth blanket approval on all types cannot be repositioned. Apply of ribs or makes of aircraft. This Aviation Glass Cloth Services LENE TRIAMINE and on curv- ed surfaces to prevent runs and one full coat of Butyrate thin- method if approved by the CAA Procedure For Obtaining give a degree of hold, a small ner. Use care in positioning is the fastest, most economical amount of Godfrey L. Cabot Co., the laps to avoid any rough and practical. C.A.A. Approval Boston, Mass., "CABOSIL" is edges. The PK method approved by added. To apply, thoroughly 7. Position the next panel, use CAA for Piper J3 series aircraft 1. Execute Form A.C.A. 337 in a 3" lap over the first panel, duplicate in accordance with in- clean all surfaces with a strong is: Drill pilot hole with #50 structions on Page 7. Forward soapy solution and rinse. Brush start at center and brush Buty- drill slightly less than 3/16" these forms to your local Avi- on one coat "Epon 815", allow rate thinner on as explained in deep, use #4 PK screw with #6 above. Use same procedure plastic washer, use small star ation Safety District Office along to dry. Position glass cloth with a letter requesting appro- as previously explained. Brugh and technique for succeeding shaped patch doped on over panels. val and include in this letter a on and bond with second coat screw and plastic washer to pre- 8. Covering fuselage - use ex- vent screw shaking or backing statement as to the strip test and allow to dry. Add addition- strength of the aircraft fabric. al coats as desired for appear- actly the same method as ex- out, replacement screw size #5 if plained for wing cover applica- hole gets oversized. If the fabric is above 46 or 56 ance, although maximum tion. 3. Drill holes through outer edg- Ibs. tensile strength, additional strength is obtained with two ap- 9. After all fiberglas cloth has rib stitching through the glass plications. es of cap strips and use a Cess- been applied with thinner, pro- na rib clip or equivalent. When cloth is not required, but if the Factory instructions on "Epon ceed to follow up with a full using this method, it is recom- fabric is below 46 or 56 Ibs. ten- 815" are obtained from Shell strength application of Butyrate mended that holes be drilled on sile strength (according to the Chemical Co., 380 Madison, New York City, and are detailed for dope rejuvenator, one applica- opposite sides of the ribs and wing loading and placarded air tion only. Allow to dry approxi- the clips installed at an angle speed) it is necessary to state specific room temperatures, etc. NOTE: mately 24 hours. across the rib in order to take in the letter and on the form 10. Brush or spray on two full advantage of the rib reinforce- A.C.A. 337 that regulation rib Do not fail to use your free consultation service when assist- strength coats of Butyrate dope. ment tape. stitching or rib attachment will 11. Spray on two coats of alu- 4. There are other methods that be performed as follows: ance is needed. '_ minized pigmented Butyrate can be devised. (Reference: see "Sub Marginal Suggested Fiberglass dope. Note: If a smooth sur- Prior to installation of glass Fabric Application") face is desired the first silver cloth over sub-marginal fabric, 2. Upon receipt of your letter Cloth Application Method coat should be well sanded us- you should contact your local and forms A.C.A. 337, the lo- ing wet-or-dry paper. Aviation Safety Agent (Main- cal A.S.D.O. then forwards the 1. Thoroughly clean all fabric to be covered. Any non-waxy 12. Spray on a minimum of two tenance) and advise him of your file to their Regional Office color coats. Note: If color is proposed repair, for currently, where it will be monitored, ap- detergent or soap such as Tide, Perfect, etc., are ideal. Use a not desired, and the surface is to the CAA has indicated that such proved and returned to the local be left in aluminum color, then repairs are approvable, never- A.S.D.O. for return to you. rather strong solution. 2. Thoroughly rinse off the incorporate two extra dope ap- theless there is a possibility that Epoxy Resin As A cleaning solution with clear wa- plications in #10 above. due to conditions or circum- 13. Using the method outlined Bonding Agent ter and allow to dry. stances beyond their control, 3. (a) Full wing, or top and bot- produces a reasonably smooth it could become necessary to This process has several ad- tom cover. Cut fiberglas cloth surface. withdraw approval of sub-mar- vantages over the aircraft dope in lengths start at , 14. The best results will be ob- ginal fabric repairs. bonding method, the principal allow 2" lap, then over top of tained if the aircraft is stored Remember, always contact advantages being improved tear wing, around back for at least one full day to allow your local CAA agent before resistance (dope thinner removes to trailing edge and allow a 2" for drving out of the dope. starting any project, and don't a considerable amount of the lap. depend on the local aviation starch and oil binder, thus mak- (b) Top covering only: Cut Sub-Marginal Fabric personnel for important infor- mation. As one operator used ing the glass cloth somewhat fiberglas in lengths, starting at Applications : brittle), rapid application, the trailing edge; allow a 2" lap to say -"when you are sick you resin dries in approximately 1- under trailing edge. At leading For approval of fiberglas cloth certainly don't go to the local 2 hours and generally 3 coats edge allow a minimum of 3" be- over aircraft fabric with a strip apothecary, you go to the doc- are sufficient. No color need low center of leading edge, pre- test tensile strength below the tor". Why not let the regula- be added as the resin - glass ferably to center of front . CAR minimums of 46 and 56 tions work for you - why make cloth permits the original color This extra material will serve Ibs., see CAM 18, page 112, them work against you. to show through. The serious two useful purposes, first as an table 3-1, Texile fabric used in disadvantages are: Epoxy resins abrasion strip and second, to aircraft covering. Information To Be are not generally stocked lo- markedly reinforce the entire Aircraft covering that has a Included On cally and must be shipped in. A leading edge. tensile strength below the CAR Form ACA-337 " considerable degree of skill is 4. After all fiberglas panels have minimum can be reinforced required in mixing the resin been cut to proper length and with fiberglas HG-12 cloth and The following information and catalyst to obtain desired tailored to fit around all pro- is approvable by the CAA pro- should be included on the Form results. The factory instruc- jections and fittings, remove and viding a satisfactory attachment ACA-337 and submitted either tions must be carefully followed. store in a clean place until need- to the ribs is accomplished. to a CAA safety agent or to a Coloring is difficult to control ed. There are several methods of qualified DAMI fojr approval due to small quantities of resin 5. Start at the , care- doing this. prior to the aircraft being op- pixed. The Epoxy resins are fully place a panel in position 1. Conventional rib stitching erated. Your failure to do sp NOVEMBER, 1956 EXPERIMENTER PAGE 11 may result in a violation action Scott version had a three foot ing total is second only to the inasmuch as the application of The Standard high radiator mounted on top Jenny production record of over fiberglas cloth to aircraft is con- of the fuselage, right between 5,000 for the period. The plane's sidered to be a major repair. and forward of the cabane struts resemblance to the Jenny is 1. Complete the front side of Model "J" This gave the pilot as much for- more than visual. Some com- the Form ACA-337 as for any by Tom Henebry parison figures are shown be- regular major repair. It would take a real expert ward visibility as a sports car Standard Curtin "J" JN-4D 2. On the reverse side, at least to identify this old tinier. This driver following a moving van. Span (upper) 43' 43' 7%" the following data should be in- At 72 MPH top speed this was Span (lower) 31' 33' HVi" Standard "J" is another of Paul Length O.A. 27' 2" 27' 3" cluded: Mantz's fabulous airplanes. One not a tremendous handicap pro- Weight empty 1350 Ibs. 1430 Ibs. Top Speed 72 MPH 75 MPH Fiberglas cloth #HG-12 in- of two built for "The Lindberg vided the intrepid airman was Landing Speed 40 MPH 45 MPH stalled over original fabric as Story" and several other movies, not subject to neck disorders. Structurally the airplane is follows: Examples this plane was built from the Designed as a trainer, the plane typical of planes in the period Right wing - on upper surface ground up, it is not a restored must have been considered suc- preceding World War I. Ash only. antique. Guiding genius of cessful or someone would have and braces were used Left wing - on top and bottom Mantz's Air Force is Mr. Otto found out before they produced with cable in a Pratt surfaces. Timm, a pilot and plane builder 1600 of them. This astonish- truss pattern. Wing construc- Fueslage - entire fuselage - from way back. He is probably or top and left side only . best known for the aircraft his - both sides. own company produced a few - left side - top and years back. A real stickler bottom - right side bottom only. for authenticity, he insists on A. One (1) application of Bu- every detail being exactly as the tyrate thinner. original. This plane even has B. One (1) application of Bu- ash engine bearers to prove the tyrate rejuvenator. point. C Two (2) coats aluminized As far as the original Stan- Butyrate dope sprayed or brush- dard is concerned, it was pro- ed on. duced by the Standard Aircraft E. Two (2) coats Butyrate color Corp. of Elizabeth, N. J. 1916 dope sprayed or brushed on. production models were powered F. The above method of appli- by 90 H.P., four cylinder, water Tom Henebry cation is identical to the method cooled Hall-Scott engines but 1956 version of a 1916 Standard Model "J" all dressed up in approved 8-12-55 by KC-250 later versions sported OX-5's movie make-up for its role in a forthcoming movie. Built at Paul for Aeronca N81968. and like the one shown here, Mantz's shop, it is not a reconstructed job but a brand new air- G. Ribstitching - none - or as 150 H.P. Hisso's. The Hall- plane. explained in the body of the ex- planation portion of your kit. tion utilized routed spruce spars H. Fabric strip test tensile and a thin, undercambered air- strength prior to application of foil (RAF -6). The double glass cloth___ IDS., this figure bay biplane had on the must be 46 or 50 Ibs., or more, top wing only and 2 Vz ° incidence or handled in accordance with in both wings. One unusual the instructions in the body of feature is the swept back upper wing, definitely not for sonic the kit, relative to "Submar- ginal Fabric Repairs". barrier penetration, but a novel feature in 1916. I. Seyboth or Maule test prior t o application —————————. Messrs. Mantz, Timm and all of their staff should be con- J. Seyboth or Maule test af- gratulated on the beautiful job ter application —————————. they have done in recreating an K. Seyboth or Maule test re- airplane long forgotten. True, port dates. (Note: add 90 days it's for a very unromantic finan- to original approval date. If cial reason but I believe they approval date is 1-10-56, then Tom Henebry must get the same sort of kick test dates would be 4-10-56, 7- Close up of the business end of this 150 H.P. Hisso powered out of it as any EAA member 10-56, 10-10-56.) vintage type airplane. Swept back upper wing is evident in this gets out of seeing his own crea- L. Any other data you may de- view. tion ready for flight sire to include or the CAA may request. the operator reports that the co- End of Form ACA-337. ——— — vering is still in excellent con- dition. Fiberglas Cloth This information should be brought to the attention of all On Spray And spray operators using fabric cov- Industrial Aircraft ered aircraft. Note: It is not advisable or rec- Fabric deterioration has been ommended that you attempt to a real and serious problem to apply fiberglas cloth over fa- the spray operator especially bric that shows any consider- those dispensing chemicals us- able evidence of deterioration ing an oil base, and usually fa- due to chemical damage as sep- bric trouble develops in about aration may occur. 18 months. (For further details and prices, Tom Henebry The first known use of fiber- write to Plastic Sales and Manu- One of Paul Mantz's Jennys is shown here for comparison glas over fabric was on a spray facturing Co., 3023 McGee Traf- with one of its contemporaries, the Standard "J". At any distance plane about four years ago, and ficway, Kansas City, Missouri.) these planes would present a recognition problem.