Author: Mike Garton

Edition: Model Aviation - 2000/10
Page Numbers: 87, 88, 91
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RC Soaring

Mike Garton, 506 NE 6th St., Ankeny IA 50021; E-mail: [email protected]

Overview

This month I'll review a new video: The 3 R's of Thermal Soaring. I'll provide brief highlights of the Midwest Slope Challenge 2000. Then I'll include information about a rocket glider demonstrated at Lake Wilson, Kansas, and radio control (RC) rocket gliders in general.

The 3 R's of Thermal Soaring (video)

John Roe and Joe Wurts put together an instructional video about thermal flying. Joe is a World Champion pilot, and Joe and John are on the 2000 US F3J Team. They made the video to raise funds to help the team. Joe reconfirmed his dominance by winning the International Hand Launch Glider Festival a week before my deadline. It's widely regarded as the most competitive HLG contest in the world.

The 3 R's of Thermal Soaring is not a professional, glitzy video. It is very useful for learning how to locate, core, and ride thermals. The Rs in the title are:

  • reading the air and the thermals,
  • riding the thermals up and out,
  • recording lost thermals.

The tape is one hour and 20 minutes long.

Much of the footage is of Joe hand-launching. He describes techniques for using ground signs to locate thermals. Before each throw, he points out the clues that show him where a thermal is likely to be. Joe repeatedly throws the glider, flies his model to the likely area, and finds the thermal.

In the interest of time, the video has been edited so that Joe finds the thermal with each toss. He said he was actually successful in finding the thermal approximately 80% of the time. Wouldn't it be nice to know roughly where the thermal is before you launch 80% of the time?

Joe's comments on coring and riding the thermals were particularly interesting. He illustrates the concepts in a classroom setting, then demonstrates them with flights. There is a detailed discussion on interpreting the winds near the ground. Joe also describes the most effective search patterns for winch-launched airplanes.

Ignore the rough edges in this video; it is the content that counts. Beginners and intermediate pilots will learn a lot. Even expert pilots will probably gain new tidbits of strategy from Joe's teaching.

The video is $20, and the money goes to a good cause. John Roe takes cash, check, and credit cards. His contact information is given at the end of the column.

Midwest Slope Challenge 2000

The Midwest Slope Challenge is held each May at Lake Wilson, Kansas. It is the largest slope event in the Midwest.

This year, Loren Blinde and his crew from the Lincoln Area Soaring Society (LASS) ran four classes of competition:

  • Foamie Combat,
  • 60-inch One-Design Racing (ODR),
  • Unlimited racing,
  • Foamy Warbird Racing.

Forty-nine pilots showed up to compete. Dave Sanders won the Combat event; Charlie Richardson won the ODR race; and Paul Wright came all the way from England to win the Unlimited race. The warbird race was canceled because of the lack of suitable wind.

Paul Wright flew what he called a "10-year-old refugee" from the US F3B Team. He explained that it was an F3B Eagle that was crashed, discarded, salvaged, then rebuilt. Paul was given a Lifetime Achievement award at the banquet. He ran the Midwest Slope Challenge for six years, prior to moving to England two years ago.

Each year, the LASS crew plans to run the contest Friday and Saturday. This leaves Sunday as a fallback in case the weather does not cooperate.

The wind cooperated partially this year. Saturday was the only day with winds strong enough for the contest classes. Sunny conditions with 0–5 mph winds prevailed Friday and Sunday. The contestants entertained themselves with light-air slope airplanes, thermal flights, bungee launching, electrics, and a rocket glider.

At the end of this column is a link to a more-complete write-up, with all the placings.

Bungee Launching

In glider vocabulary, a bungee is a length of large-diameter surgical tubing used like a single-strand glider slingshot.

Unlike a hi-start, little or no string is used and the launch path is horizontal. The rapid acceleration during a bungee launch puts extreme stresses on the airframe; this method should only be attempted with very strong and relatively clean airplanes. The glider also needs to be built straight and trimmed out perfectly.

A helper releases the airplane. Before you can count to two, the glider is off the bungee and traveling at high speed. The amount of stored energy is huge. The pilot can pull up after leaving the bungee and zoom a few hundred feet upward.

Multiplex and Northeast Sailplane Products sell bungees. If you buy one, it is vital that you read the instructions and follow them to the letter. Bungee launching can be hazardous if proper safety procedures are not followed.

Rocket Gliders and the AeroTech Phoenix

Steve Rohman demonstrated his AeroTech Phoenix rocket glider at Lake Wilson. Bob Parks designed the Phoenix and its airfoil. It has a 47-inch span and has rudder, elevator, and aileron controls.

Steve’s airplane weighs 23 ounces dry, and 27–28 ounces fully loaded. Steve sets the elevator approximately 5% downward on launch to keep the airplane from flying back over his head.

The Phoenix uses an AeroTech Reloadable Motor System. AeroTech has been selling this patented system for approximately 10 years. The machined-aluminum rocket-motor casing is reusable. Steve reports that this solid-propellant system is similar to the Space Shuttle, and yes, it does have an O-ring. Reloading the motor cartridge is fast and easy; it can be done at the field.

The AeroTech rocket motors are much stronger than the disposable rocket motors commonly seen in hobby stores. The AeroTech propellant (ammonium perchlorate) has two to three times the power for the same weight of black-powder motors.

Rocket motors use a naming convention related to their impulse strength:

  • A C motor is twice as strong as a B motor.
  • A D motor is twice as strong as a C motor.

The reloadable motors for the Phoenix go up to G; this is eight times stronger than the biggest motors (D) common in hobby stores. Reloads for these larger motors run $5–6. AeroTech sells single-use disposable motors of the same size in the S10-20 range.

Some bad news: the Phoenix kit has been discontinued. Some good news: there are higher-performance gliders available.

Kevin McKiou of Vectoraroe, Inc. sells rocket-glider kits. Kevin’s designs have consistently won S&B competitions for years. These higher-performance rocket gliders weigh approximately eight ounces during the glide. With their maximum engine size (E6), they reach 1,000 feet in 10 seconds. Dead-air times of six to seven minutes are typical.

In addition to kits, Kevin has the plans on his web site. The plans can be downloaded for personal use only.

The AMA Safety Code states that models propelled by rockets are limited to 3.3 pounds and a maximum G-size motor. They should be flown in accordance with the National Model Rocketry Safety Code.

I have included links to other rocket-glider sources. MA

Sources

The 3 R’s of Thermal Soaring video:

Multiplex USA (bungee):

Northeast Sailplane Products (bungee):

  • 140 Kirby Ln.
  • Williston VT 05495
  • (802) 658-9482

SR Hobbies (MiG-3):

Dave’s Aircraft Works, or DAW (foam warbirds):

C.R. High Performance Aircraft (Fun One):

  • 205 Camille Way
  • Vista CA 92083
  • (760) 630-8775

AeroTech Consumer Aerospace (manufacturer of reloadable rocket motors):

National Association of Rocketry (NAR):

Vectoraroe, Inc. (high-performance rocket gliders, free "Cuda" plans):

More-detailed information on rockets and rocket gliders:

Official Midwest Slope Challenge results:

Transcribed from original scans by AI. Minor OCR errors may remain.