[photo not recovered: 29783.jpg]
I am extremely cautious about stooge restraint of my airplanes when flying alone, which is nearly always. The Snaggletooth and Cavalier Mustangs have Ro-Jett .76s. The Critical Mass and BBFB Bearcat both have Saito .91s. If any one of these carbon propped airplanes were to get loose from the stooge while I am kneeling in front of them there would be injuries, possibly so severe, that I might not be able to transport myself to a hospital. In short, there is a large element of unease and a very healthy respect for the damage possible when starting these monsters.
This is my system for tailwheel/stooge restraint. The photograph above shows most of the steps that I take to restrain stooge running airplanes.
First the tailwheel wire is .077" music wire. This is large enough for safe operation and thin enough to be flexible for shock absorption after the tail wheel touches on roll out.
The first add on is the stooge hook itself which I make from .047" music wire. It is laced to the tailwheel strut with copper serving wire. There is an extra precaution here. If you look close, you may see that the top of the stooge wire above the solder joint is bent to form a small "hook". The thrust of large engines and the day to day flexing of the stooge hook joint eventually breaks the solder joint between the stooge hook and the tailwheel strut. The soldered serving wire wrapping is unharmed but the joint is loosened enough that the stooge hook can rotate slightly around the tailwheel strut. The hook on the top of the stooge above the solder joint prevents the stooge wire from slipping down through the solder joint and getting loose. In practice, this happens with regularity and is considered safe for continued use to finish a flying session. The hook can rotate slightly but it can't possibly get loose. The repair is to simply reheat the solder joint when I get home.
The next addition to the tailwheel strut is a .035" braided safety wire (leadout cable) which is securely attached at it's top end to the tailwheel plywood mount inside the airplane. From the mount, the safety wire runs down the tailwheel strut, under the stooge hook soldered bindings, and is finally attached to the stooge hook itself behind the tailwheel axle. This safety wire is bound to the tailwheel strut at several places with a few wire wraps and soldered for appearance only. If the tailwheel wire were to break, this safety wire between the tailwheel mount and stooge hook would restrain the airplane. The tailwheel strut, stooge hook, and safety wire are all together in that main solder joint above the wheel axle. The safety wire and stooge hook are additionally soldered together behind the axle.
The safety device not shown is the tailwheel mount restraint which is part of the aircraft structure. Before the bottom sheeting is installed over the bottom of the fuselage, a foot long tow of Kevlar is wrapped several times around the tailwheel strut where it leaves the mount. The two 6" ends of this tow are run forward along the fuselage bottom longeron toward the wing and is glued to both the bottom longeron and sheeting. This is to insure that a structurally damaged tailwheel mount can not pull out of the fuselage. This feature weighs practically nothing as the sheeting has to be glued to the bottom longeron anyway, but add greatly to the ability of the tailwheel mount to resist the very strong thrust of large engines.
[photo not recovered: 29785.jpg]
LAST, AND MOST IMPORTANT! All of the safety devices in the world do absolutely no good if I fail to use them. The very first preflight step I take when arriving at the field, and between flights, is to attach the airplane to the stooge. Then the lines are attached and run out. The airplane fueled. Battery power is not applied to the plug until the stooge is visually checked while moving the airplane enough to insure that it is truly engaged. Then, and only then, power is applied to the plug and the starter picked up to begin another flight of a semi-scale stunt ship.
If your model flying is stooge based, appreciate that it is inherently dangerous, particularly with large, powerful models. Safe stooge operations can be routinely done with safety only when extreme care is used in installing a strong restraint system and adhering rigidly to safe operating practices at the circle.
When joined at my site by fellow stunt flying friends, I still prefer to stooge launch. My stooge has never failed, in many thousands of flights, to give safe and predictable launches. Launches by friends have not proven to be as reliable.
Al
I am extremely cautious about stooge restraint of my airplanes when flying alone, which is nearly always. The Snaggletooth and Cavalier Mustangs have Ro-Jett .76s. The Critical Mass and BBFB Bearcat both have Saito .91s. If any one of these carbon propped airplanes were to get loose from the stooge while I am kneeling in front of them there would be injuries, possibly so severe, that I might not be able to transport myself to a hospital. In short, there is a large element of unease and a very healthy respect for the damage possible when starting these monsters.
This is my system for tailwheel/stooge restraint. The photograph above shows most of the steps that I take to restrain stooge running airplanes.
First the tailwheel wire is .077" music wire. This is large enough for safe operation and thin enough to be flexible for shock absorption after the tail wheel touches on roll out.
The first add on is the stooge hook itself which I make from .047" music wire. It is laced to the tailwheel strut with copper serving wire. There is an extra precaution here. If you look close, you may see that the top of the stooge wire above the solder joint is bent to form a small "hook". The thrust of large engines and the day to day flexing of the stooge hook joint eventually breaks the solder joint between the stooge hook and the tailwheel strut. The soldered serving wire wrapping is unharmed but the joint is loosened enough that the stooge hook can rotate slightly around the tailwheel strut. The hook on the top of the stooge above the solder joint prevents the stooge wire from slipping down through the solder joint and getting loose. In practice, this happens with regularity and is considered safe for continued use to finish a flying session. The hook can rotate slightly but it can't possibly get loose. The repair is to simply reheat the solder joint when I get home.
The next addition to the tailwheel strut is a .035" braided safety wire (leadout cable) which is securely attached at it's top end to the tailwheel plywood mount inside the airplane. From the mount, the safety wire runs down the tailwheel strut, under the stooge hook soldered bindings, and is finally attached to the stooge hook itself behind the tailwheel axle. This safety wire is bound to the tailwheel strut at several places with a few wire wraps and soldered for appearance only. If the tailwheel wire were to break, this safety wire between the tailwheel mount and stooge hook would restrain the airplane. The tailwheel strut, stooge hook, and safety wire are all together in that main solder joint above the wheel axle. The safety wire and stooge hook are additionally soldered together behind the axle.
The safety device not shown is the tailwheel mount restraint which is part of the aircraft structure. Before the bottom sheeting is installed over the bottom of the fuselage, a foot long tow of Kevlar is wrapped several times around the tailwheel strut where it leaves the mount. The two 6" ends of this tow are run forward along the fuselage bottom longeron toward the wing and is glued to both the bottom longeron and sheeting. This is to insure that a structurally damaged tailwheel mount can not pull out of the fuselage. This feature weighs practically nothing as the sheeting has to be glued to the bottom longeron anyway, but add greatly to the ability of the tailwheel mount to resist the very strong thrust of large engines.
[photo not recovered: 29785.jpg]
LAST, AND MOST IMPORTANT! All of the safety devices in the world do absolutely no good if I fail to use them. The very first preflight step I take when arriving at the field, and between flights, is to attach the airplane to the stooge. Then the lines are attached and run out. The airplane fueled. Battery power is not applied to the plug until the stooge is visually checked while moving the airplane enough to insure that it is truly engaged. Then, and only then, power is applied to the plug and the starter picked up to begin another flight of a semi-scale stunt ship.
If your model flying is stooge based, appreciate that it is inherently dangerous, particularly with large, powerful models. Safe stooge operations can be routinely done with safety only when extreme care is used in installing a strong restraint system and adhering rigidly to safe operating practices at the circle.
When joined at my site by fellow stunt flying friends, I still prefer to stooge launch. My stooge has never failed, in many thousands of flights, to give safe and predictable launches. Launches by friends have not proven to be as reliable.
Al
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