Fierce Arrow 400 (oz12067)

About this Plan

Fierce Arrow 400. Control line stunt model.

Quote: "Continued redesign and aerodynamic study of the original and famous Fierce Arrow permits this up-dating of the 1957 machine to 1968 standards and thus our latest version makes allowances for the building habits and techniques of the builders. Fierce Arrow 400, by Bill Netzeband.

As any other proud designer would never tell you, the Fierce Arrow '400' is not the ultimate precison aerobatic machine. It is a clean flying, easy to handle, tough, cheap to build and operate, fully aerobatic machine that doesn't look like all of those other airplanes. The original Fierce Arrow (oz5845) attracted a good deal of attention, particularly among hard-core procrastinators. The last of a number of requests for plans arrived in late 1964. Communications with many people who built the FA brought in mixed results. Apparently, the weight and balance of the individual airplanes varied over a wide enough range to cause some of them to be complete dogs (yours, maybe?). A complete aerodynamic study of the configuration, performed in 1965 after I dug out and developed enough information, bears out the scattered success pattern.

The flying wing configuration is critical; no doubt about it. The short length, and elevator hinged to the wing trailing edge, result in a low static margin; hence, marginal pitching stability. To obtain maneuverability with a stable CG location requires a relatively huge elevator surface (at least 20% of the wing area). We hinged the elevator of the '400' to obtain a slotting effect which increased the tolerance of CG location. A careful distribution of the lumber volume allows the FA 400 to be built with less variability in overall weight, with the CG falling within the acceptable range of locations.

The wing approach is ideal for .15 engines because the basic cleanliness allows the wing area to be large enough to achieve a decent wing loading. The minimum hardware weight forces the use of over 300 square inches, too much for a conventional layout. The real fun is steering through clean smooth maneuvers. You'll quickly see how much 'lead time' you've been giving that traditional acrobatic machine. The '400' reacts when you move, not tomorrow. Watch it, though, she may spoil you.

The world still isn't ready for a fifteen size flying wing competition stunt airplane even though we have a first place trophy from AAA Wichita, Kansas meet, in 1962. We turned the mill up for 65 mph and blazed through a full pattern in a wind that was keeping the good guys down under 45 degrees. You won't always get that chance. Besides, it was one of those wonderful days when I couldn't do anything wrong. In case you chuckled at 65 mph and 'blazed', get a stop watch. Everyone flys the pattern between 52 and 60 mph!

The side area distribution was derived from experiment and with the wing fences. She goes over the top light on tension, but solid. Flying speeds should be between 52 and 58 mph. Lines are either 60' x .010 dia or 55' x .012 dia with a .15 engine and 65' x .010 dia or 60' x .012 dia with a .19 mill. Props are 8-5 wide blade (Top Flite or Cox Nylon) for 15's and 9-5 wide blade with 19's. In general, fuels should be mild, such as K&B 100 and Cox Blue Can, or a 10% to 18% nitro home brew. The engines listed on the plans have been tried and worked OK. We must mention that the Fox 15X has to be a strong one, capable of turning the 8-5 prop over 13,000 rpm. Medallions are uniform in quality, and the Enya 15 III at $9.95 is the best bargain on the 1968 market. Don't bother with the Enya 15 I or II, however. The real beauty of the FA 400 is in its compactness and ability to do a lot of flying for less money. Your fuel (2 oz), engine costs, initial lumber, and finish costs are about half. So build two!

CONSTRUCTION: Recognizing that a straight true wing is 76% of the battle, we arranged thing to complete the wing structure while it is still pinned down to the work surface. After you pick up your stick of light (5 to 8 pounds density) balsa sheets and medium (8 to 12 pounds) spars and leading edge stock, spend a few relaxing hours cutting out all of the parts.

Your first assembly will build the nose section, firewalls, engine beams, etc, including the wing root ribs (W1) and W1A. Leave the 1/2 inch cowl block for later. Use white glue, aliphatic resin glue, epoxy or polyester resin for this job. Once it is square and set, pin the assembly down over the plan in the upright position with the bot-tom trailing edge in place. Pin and block the tip ribs in place and carefully square them. Pop the bottom spars into place, gluing all the way. Follow rapidly with the leading edges, the ribs and the top spar and top trailing edge piece..."

Direct submission to Outerzone.

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