Quick Tip: Shaping Curves Into Longerons

Many fuselage plans call for bends in the longerons, particularly around the nose area. If the curve is very slight, we can usually just flex the longeron into shape and pin it until the glue dries. But trying to do this with sharper curves puts stress on the airframe, and the fuselage may distort as the longerons strain to return to their natural shape. This week’s tip presents three ways to pre-shape curves into longerons permanently, to help you achieve tight bends without stressing your structures.

Setting a Curve With Steam

Gently bend the longeron while holding it over the spout of a steaming kettle, and it will hold the shape once removed. Check the curved piece against the plans and steam again as necessary.

Setting a Curve With Hot Water

Soak your longerons in hot water for a few hours and then pin them to the correct shape. When dry, they’ll be warped to the curve you desire.

Setting a Curve by Laminating

Carefully slice part of the longeron in half lengthwise. Start from the nearest end of the longeron and cut to the point where the curve will end (you’ll need a balsa stripper or a steady hand for this). Apply your favorite glue between the laminations, and pin the longeron to the correct shape.

Got a tip you would like to share? We could use your input! Learn how to contribute.

June 20, 2010 in Free Plans by Arjun

R1 Chambermaid – by Bernard Guest

FAC legal pseudo-dimescale. 16 inch wingspan. based on Bill Henn’s Chambermaid, includes printed tissue patterns. Download the plans.

June 19, 2010 in Articles, Model Showcase by SFA

Bob Isaack’s Warbirds

Bob Isaack's Model P-51B Warbird

In this issue of Spotlight we present the handsome free-flight models born of Bob Isaack’s talent. Here, Bob describes how he created his outstanding detail work. This P-51B was scratch-built from Mike Midkiff plans. The details were rendered with fairly simple techniques, as follows:

This model was covered with JCI tissue (olive drab) and doped with nitrate dope. The white letters were cut from Coverite “Coverlite” synthetic tissue, and applied with nitrate thinner. The thinner must be used very sparingly to prevent the dark color from shining thru the light colored tissue.

Bob Isaack's Model P-51B Warbird

Control surface markings (white) were added using a Pentel “Milky” gel roller pen acquired from an art supply store. This was also the technique used to add panel markings; this system looks good on aircraft covered with “dark” tissue.

The windows to the rear of the cockpit are glued to the inside of a piece of 1/64 plywood wrapped over the front and rear formers. This gives a realistic “lip” or edge to those windows.

Bob Isaack's Model P-51B Warbird

The inside rear of the cockpit was painted with Modelmaster zinc chromate green. The German “Kill” markings came off the internet – I simply printed the page, cut the markings out, and glued them on white glue. The antenna at the rear of the cabin was made with .006″ monofilament fishing line.

The Mustang does 90 seconds on 5 loops of 1/8” supersport, and will be flown in the FAC Scale event at Geneseo.

Here are a few more models Bob built, using the same detailing techniques:

This Swiss EKW-3603 WWII fighter was scratchbuilt from a Bill Henns plan. It regularly does 2 minutes on three loops of 1/8” supersport rubber, and is being saved for WWII mass launch at Geneseo this year.