I RECEIVED the first photos of the season from Jim Schneider (Livermore CA). His Profile F8F Bearcat is shown this month. Jim built the model from Brodak kit plans. Modifications include the line-slider and bellcrank on top of the wing. The model uses the Webra 32, which is a capable engine right out of the box. It is also very light, at only 7 3/4 ounces for the bare engine without the throttle. That's even lighter than the Nelson AAC (aluminum-aluminum chrome) Combat engine by approximately one-quarter ounce. In addition to the Bearcat. Jim flies a Sterling F4U Corsair and a Class II Guardian. He reports scores high enough to ensure a place in the top 10 nationally in each event. Jim flies with tongue-style mufflers and 15% fuel in all three classes, although he expected to remove the mufflers for the Northwest Regionals. There should be proposals this year for allowing mufflers in Carrier and for restricting fuel to relatively low nitromethane content—most likely 10%. Experience from Carrier modelers like Jim will be essential to arriving at appropriate rules for consideration and in the final decision on whether or not to adopt the rules. I hope that anyone with experience with low-nitro fuel and/or mufflers will share his or her experiences and performance data to help in the rule-making process. If you'd like to share your opinions and experiences, you may write or E-mail me at the addresses at the top of the column. In addition to sharing your experiences, 1 hope that contest data reports will include information about what nitro-content fuel is used by each contestant and whether or not a muffler is installed. If mufflers are used, a description of the muffler and a general impression of its effect would be helpful. Although mufflers are not allowed by the rules, it is possible to allow mufflers as an exception as long as the deviation is publicized adequately before the event. The only limitation if mufflers are used is that scores will not qualify for AMA records unless the muffler complies with the existing three-inch limit for exhaust extensions. Tongue mufflers that comply with the three-inch rule can be made or purchased. Please consider allowing mufflers if your club sponsors a Navy Carrier event. The principal reason cited by most Carrier modelers for considering the use of low-nitro fuel is the increasing problem of finding an appropriately fuelproof finish for our models. The high-nitro fuels are destructive to most finishes, except epoxy, and the hobby-specific epoxy paints are out of production. There are some clear epoxy paints available to use as topcoats, but you will have to confirm compatibility with your underlying color coats before using them on your models. David Ramsey reported in the January/February Stunt News (original article in the Exhibits newsletter) that The Home Depot® sells a clear epoxy under the brand name Evercoat®. It also sells thinner that is compatible. If you try it or any other potential solution to the high-nitro fuel-proofing dilemma, please let me know so I can share the information. Fred Cronenwett (Canoga Park CA) provided me with photos following the refurbishment of the Whittier Narrows deck in the Los Angeles. California, area. The deck is concrete on a grass circle, but the techniques are applicable to mounting lines on any paved surface. Putting a deck on a paved circle is relatively simple and offers the advantage of multiple uses for the circle without the requirement of building a plywood deck, as is necessary for flying from grass. Even a paved segment of a grass circle can be less expensive and easier than a plywood deck. A significant consideration for any deck is the arresting-line construction. The lines themselves are base made from parachute cord. The smooth nylon is relatively small in diameter, slides easily through the line guides, meets the minimum strength requirements, provides a little elasticity, and is usually relatively easy to obtain at large hardware stores. The bags are more challenging. If you have access to a heavy-duty sewing machine, or if you can substitute a larger needle in a standard machine to use heavy thread and penetrate the fabric without breaking, the best material is denim. The best source is legs cut from old blue jeans. Fred found an alternative that costs slightly more but avoids the construction aspect almost entirely. The photo shows a "utility pocket." which is one of many cloth accessories from the Camp Inn brand of camping products (Cerf Brothers Bag Company, Saint Louis MO). I have found them or similar items in many outdoor stores that cater to the camping or hiking enthusiast. The bags Fred used are 8x10 inches, and they will accommodate the sand inside a heavy-duty Ziploc® freezer bag. The zipper at the top allows a triangular wire harness to be inserted through the top of the bag before the zipper is closed. The wire is attached with plastic cable tics to a wooden stick the width of the bag. The wooden stick spreads the load on the bag and keeps the wire from deforming during arrested landings. The arresting cable is tied to the wire harness. The line supports used at Whittier Narrows are shown in the photos. They are screwed into expandable screw anchors which are inserted in holes drilled in the concrete. When the line supports are not installed, the holes are plugged with setscrews the same diameter and thread as the bolts used for the line supports. An alternative method, though there is a slight increase in the likelihood of snagging a control line on a missed landing, is to use threaded eye hooks. If you are not concerned about debris filling the holes or are willing to keep them clean with maintenance every few years, galvanized pipe large enough to accommodate the screw eyes without worrying about threading them has worked quite well. In asphalt, it might even be possible to drive them through the surface without the necessity of drilling holes. Be sure to try it before committing to that method. That's all for now. I hope your summer flying season has been going well.
Edition: Model Aviation - 2002/10
Page Numbers: 132, 133
Edition: Model Aviation - 2002/10
Page Numbers: 132, 133
I RECEIVED the first photos of the season from Jim Schneider (Livermore CA). His Profile F8F Bearcat is shown this month. Jim built the model from Brodak kit plans. Modifications include the line-slider and bellcrank on top of the wing. The model uses the Webra 32, which is a capable engine right out of the box. It is also very light, at only 7 3/4 ounces for the bare engine without the throttle. That's even lighter than the Nelson AAC (aluminum-aluminum chrome) Combat engine by approximately one-quarter ounce. In addition to the Bearcat. Jim flies a Sterling F4U Corsair and a Class II Guardian. He reports scores high enough to ensure a place in the top 10 nationally in each event. Jim flies with tongue-style mufflers and 15% fuel in all three classes, although he expected to remove the mufflers for the Northwest Regionals. There should be proposals this year for allowing mufflers in Carrier and for restricting fuel to relatively low nitromethane content—most likely 10%. Experience from Carrier modelers like Jim will be essential to arriving at appropriate rules for consideration and in the final decision on whether or not to adopt the rules. I hope that anyone with experience with low-nitro fuel and/or mufflers will share his or her experiences and performance data to help in the rule-making process. If you'd like to share your opinions and experiences, you may write or E-mail me at the addresses at the top of the column. In addition to sharing your experiences, 1 hope that contest data reports will include information about what nitro-content fuel is used by each contestant and whether or not a muffler is installed. If mufflers are used, a description of the muffler and a general impression of its effect would be helpful. Although mufflers are not allowed by the rules, it is possible to allow mufflers as an exception as long as the deviation is publicized adequately before the event. The only limitation if mufflers are used is that scores will not qualify for AMA records unless the muffler complies with the existing three-inch limit for exhaust extensions. Tongue mufflers that comply with the three-inch rule can be made or purchased. Please consider allowing mufflers if your club sponsors a Navy Carrier event. The principal reason cited by most Carrier modelers for considering the use of low-nitro fuel is the increasing problem of finding an appropriately fuelproof finish for our models. The high-nitro fuels are destructive to most finishes, except epoxy, and the hobby-specific epoxy paints are out of production. There are some clear epoxy paints available to use as topcoats, but you will have to confirm compatibility with your underlying color coats before using them on your models. David Ramsey reported in the January/February Stunt News (original article in the Exhibits newsletter) that The Home Depot® sells a clear epoxy under the brand name Evercoat®. It also sells thinner that is compatible. If you try it or any other potential solution to the high-nitro fuel-proofing dilemma, please let me know so I can share the information. Fred Cronenwett (Canoga Park CA) provided me with photos following the refurbishment of the Whittier Narrows deck in the Los Angeles. California, area. The deck is concrete on a grass circle, but the techniques are applicable to mounting lines on any paved surface. Putting a deck on a paved circle is relatively simple and offers the advantage of multiple uses for the circle without the requirement of building a plywood deck, as is necessary for flying from grass. Even a paved segment of a grass circle can be less expensive and easier than a plywood deck. A significant consideration for any deck is the arresting-line construction. The lines themselves are base made from parachute cord. The smooth nylon is relatively small in diameter, slides easily through the line guides, meets the minimum strength requirements, provides a little elasticity, and is usually relatively easy to obtain at large hardware stores. The bags are more challenging. If you have access to a heavy-duty sewing machine, or if you can substitute a larger needle in a standard machine to use heavy thread and penetrate the fabric without breaking, the best material is denim. The best source is legs cut from old blue jeans. Fred found an alternative that costs slightly more but avoids the construction aspect almost entirely. The photo shows a "utility pocket." which is one of many cloth accessories from the Camp Inn brand of camping products (Cerf Brothers Bag Company, Saint Louis MO). I have found them or similar items in many outdoor stores that cater to the camping or hiking enthusiast. The bags Fred used are 8x10 inches, and they will accommodate the sand inside a heavy-duty Ziploc® freezer bag. The zipper at the top allows a triangular wire harness to be inserted through the top of the bag before the zipper is closed. The wire is attached with plastic cable tics to a wooden stick the width of the bag. The wooden stick spreads the load on the bag and keeps the wire from deforming during arrested landings. The arresting cable is tied to the wire harness. The line supports used at Whittier Narrows are shown in the photos. They are screwed into expandable screw anchors which are inserted in holes drilled in the concrete. When the line supports are not installed, the holes are plugged with setscrews the same diameter and thread as the bolts used for the line supports. An alternative method, though there is a slight increase in the likelihood of snagging a control line on a missed landing, is to use threaded eye hooks. If you are not concerned about debris filling the holes or are willing to keep them clean with maintenance every few years, galvanized pipe large enough to accommodate the screw eyes without worrying about threading them has worked quite well. In asphalt, it might even be possible to drive them through the surface without the necessity of drilling holes. Be sure to try it before committing to that method. That's all for now. I hope your summer flying season has been going well.
