Two-Line Speed Plane: The 160.5 mph "Monitor" National Record Holder

1955 Air Trails Hobbies for Young Men Annual Edition

Annual Edition 1955 Air Trails

Table of Contents These pages from vintage modeling magazines like Flying Aces, Air Trails, American Modeler, American Aircraft Modeler, Young Men, Flying Models, Model Airplane News, R/C Modeler, captured the era. All copyrights acknowledged.

Control Line Speed always seemed like a great aspect of competition to get involved in, but like so many others, I just never made time for it. There are some really cool videos on YouTube of C/L Speed models being flown. On a properly adjusted engine, you can hear the engine break into a screaming 2-cycle mode after the airplane picks up some speed and the propeller unloads a bit from the pilot whipping it. It is like seeing / watching the afterburner kick in on a jet engine! A major change in the design of Speed models from the 1955 vintage of this "Monitor" is the use of a wing only on the inside. Rules require a minimum span and projected area, so putting the wing on the "slow" side achieves the goal. I would love to have witnessed the first time some guy presented his model to a judge with the wing only on the inside and smiling as he challenged said judge to show where the rule book says the wing must be on both sides of the fuselage.

This video is Paul Eisner, from Surrey, United Kingdom, showing the setting of an F2A 2.5 cc world record for Control Line Speed. Listen to that engine!

Two-Line Speed Plane: The 160.5 mph "Monitor" National Record Holder

By Leland S. Morton, Jr.

My modeling career started at an early age with rubber power models; I started flying free flight gas models in 1939. Then when U-control came along I learned how to fly an original speed ship with an Ohlsson .23 engine with a top speed of 60 miles an hour. Later, finding Fireballs and my own designs more enjoyable to fly, I learned stunt and precision while working in a hobby shop. As contests became more numerous I flew stunt at most of them, winning a few trophies and engines. Then combat became the thing. I did very well in combat but lost too many airplanes.

What led me to building the "Speed Monitor" was my last combat ship. Considerable design and construction hours were put into it and at its first contest it was completely destroyed - unnecessarily. I was very discouraged, so I built speed ship #13 using some original ideas that didn't jibe with the experts.

This is the plane that "Doesn't Have It!" By that I mean as far as possible anything that would tend to hold it back was eliminated.

It features a "pressure ease" cowl based on a theory that if properly channeled there is enough ram air to cool the engine, eliminate hot spots and prevent air from stacking up in front of the cowl. The engine is a stock engine and the fuel was stock fuel ("This-Is-It" hopped up). The prop was a stock 9/12 Tornado. The engine was Liqua-Moly treated before it was run. First flight right out of the box was 155.11, which broke the national record. Second flight was 153 at the first record trials held in Dallas. It wasn't flown at the second record trials because of the weather. At the third trials held February 21, it turned 156.32 first flight and 160.51 second flight with a stock 9/12 Tornado and stock fuel pepped up a bit.

The construction method is not new inasmuch as crutch types have been used some 15 years or more. It is, however, entirely hard wood except the channeling inside the cowl which is balsa. You start by grinding the fins off on each side of your engine until they are flush with the outer screws in the head, covering up and protecting the engine where necessary. This is done to reduce frontal area.

A Hell Razor pan was used, and modified by cutting rear skid off and filing all excess metal off. The engine was then mounted. A 1-3/4 Froom spinner was used with a 1/8 back plate turned on a lathe to keep it from binding on the fuselage when you tighten the prop. The fuselage top was sawed out to the shape of the pan, using a piece of basswood 3/4" x 2 1/2" X 18"; then sawed to take engine.

Next the wing the wing was laid out; the dihedral was cut with a hand saw before laying out the outline. The airfoil is a perfectly symmetrical section which according to theory flies at a slight positive angle of attack. I couldn't find anyone who could measure it while it was flying 155.11 or 160.51, so theoretically it's inefficient, but there was no "lift" holding it back.

The rudder was made of 1/8" plywood and offset 3 degrees to help follow the circle. Fuselage top was planked with 1/8" plywood extending from the two-thirds point on the wing to about midway of the rudder. The remaining distance was filled in with scrap balsa because of working ease. The elevator was 1/8" plywood; both elevator and rudder are symmetrically shaped. The cowl sides of 1/32" plywood are glued to the top of the fuselage and wing. The balsa channeling was put in before the top (which is recessed) was glued in place. Be sure and tape your cylinder head with about a 1/64" layer of masking tape to give side clearance when fitting. After the cowl is finished carve the front of the fuselage to fit the spinner, tapering up into the cowl.

Plastic Wood was employed to make fillets on cowl and wing. Cover all fillets with raw silk.

Finish as desired.

Monitor Plans

Full- size plans for Speed Monitor are part of Group Plan #55 A from Hobby Helpers, 770 Hunts Point, New York 59, N. Y. (50¢)

Posted March 8, 2014