Introduction To Indoor Towline Gliders
By Kurt Krempetz


The September 2006 issue of the Bong Eagles (indoor freeflight club in Milwaukee, Wisconsin) newsletter announced that they were sponsoring a new indoor towline glider event at their fall contest. The simple rules were designed to spur interest in the contest by creating a fun event where you can use old parts from a Limited Penny plane to participate.

The Rules

The rules are as follows:

  1. Limited Penny Plane wing and stab-rules/restrictions.
  2. Fuselage: 24" Maximum Length.
  3. Minimum weight: 3.1 grams.

The October Thursday Fun-Fly Night

Starting in October 2006 and ending in April 2007, the Bong Eagles sponsor a monthly fun-fly at Memorial Hall in Racine, Wisconsin, on the first Thursday of every month. The hall has a 41" ceiling. It is a good Category II site. In October, three individuals had already assembled an indoor towline glider for the event. I assembled one, build from Lew Gitlow's Novice Class Penny Plane parts. The model towed up well, after some adjustment, and also glided nicely. I was able to turn around 50 seconds.

New Design - ToFu

Plans for the TuFo are available on this website. After three flying sessions, I designed this indoor towline glider, which follows the Bong Eagles' current rules. The changes I made from my first plane were that I strengthened the model and reduced the stab area. I am sure this design will be improved in the future. As a starting point, I decided to publish the plans.

Bong Eagles Annual Fall Contest

The results of the Bong Eagles Annual Fall Contest for 2006 can be found at There were eight contestants entered in the event. I believe all had a great time. IT was clear that towing the glider was not a simple task, and many had problems. On the other hand, an experienced Chuck Markos didn't have any problems towing his glider, and actually circle towed it, until he was at the very top of the ceiling, before releasing the model off the towline. In the ToFu plans, I have added a modified tow hook, similar to Chuck's, that will allow you to circle-tow it.

Happy flying!

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