Jetstream A1 Towline Glider Build Report

Admittedly I did not give the selection of the Jetstream towline glider too much thought when picking this project to build. I was ordering from Jim O’Reilly Plans and decided after selecting the Wilbur Old Time rubber model to order another plan and short-kit. The Jetstream was a name I had heard of and I wanted to give the towline event a try. 

Jetstream Test Glide

The Jetstream was designed by Warren Kurth back in the late 1950’s and won the Nats 1959, 1960, and 1961 as well as setting a record for A1 towline glider. It was originally kitted by Ambroid the glue maker but was later kitted by Midwest and more recently by BMJR. The short-kit of the Bob Holman laser-cut parts even included the fuselage sides, the short kit you can purchase along with the plans from Jim O’Reilly plans.

Before Covering

Starting Construction

Construction was very straightforward and the glider framed up pretty fast. I had some decisions to make before completing the model such as covering material, DT system and how to setup up the autorudder. From opinions I received, Esaki tissue appeared the preferred covering, I did use a ribbon of double thickness covering in the wing to try to increase the stiffness.   For DT I originally was going to use a fuse but after seeing a picture of the Jetstream Rudy Kluiber had built I decided to use a mechanical timer, I selected the Micro DT from Texas Timers which I had also used in my Retro Gnome hi-start glider. For the autorudder I purchased  ASTOP rudder adjuster from Larry Davidson and allowed for adjustment in the tension of the line by using a tiny micro RC clevis. Tension in the opposite direction is with a tiny rubber band.

Line Tension and ASTOP Rudder Adjuster

Adjustable Towhook

Before building the Jetstream I built a Retro Gnome hi-start glider which uses a small rubber strand and a length of Dacron line to pull up the glider. Like the Jetstream towline the Retro Gnome also used autorudder to start the glider flying in a circular pattern while flying straight on tow. My thought was to learn how to get this adjusted with the smaller Retro Gnome before attempting the larger Jetstream and having to run while towing. On the Retro Gnome I had some trouble with the autorudder pin coming out so I changed it to be like the method used on the Jetstream which is a pin with a washer with line fastened to it. 

Retro Gnome Hi-start Glider

I did get some test glides of Jetstream this spring and the glide looks pretty good. One nose weight compartment has not been covered over yet so I can tweak the CG for glide. This coming weekend I hope to try the Retro Gnome again.  There is so much to experiment with when you build free flight model airplanes.



Bill Kuhl
http://www.ideas-inspire.com


Related Links

Jim O’Reilly Model Plans - http://www.jimoreillymodelplans.com/prodserve.htm
ASTOP Rudder Adjuster -  http://www.modelflight.com/larrydavidson.html
Texas Timers Micro DT - http://www.texastimers.com/
Warren Knuth Biography - https://www.modelaircraft.org/files/KurthWarren.pdf
Retro Gnome Build Report - http://scienceguyorg.blogspot.com/2016/12/building-retro-gnome-ff-hi-start-glider.html