Digester - plan thumbnail image

Digester - completed model photo more pics (5)

by Don Mathes
from RCMplans (ref:137)
December 1964 
72in span
Tags: IC R/C
all formers complete :)
got article :)

Submitted to Outerzone: 06/11/2014
Outerzone planID: oz6097 | Filesize: 396KB | Format: • PDFbitmap | Credit*: JeffMac


About this Plan

Digester - Digicon Tester - Radio control sport trainer model for Veco .45 power.

Quote: "The Digester is, in many ways, one of the most remarkable models we have ever had the pleasure of building and flying. The finest proportional trainer available today, it will perform the entire AMA pattern with ease. Although the construction is completely straightforward..."

72in span, 1000 sq. in., .45-.61, 4 channel radio. Model # pl-137. Designed by Don Mathes. Featured in RCM 12-64.

Direct submission to Outerzone.

Supplementary files

Article pages, text and pics.


Did we get something wrong with this plan? That happens sometimes. Help us make a correction


User comments

Don Mathes and Doug Spreng have the distinction of designing the very first digital proportional radio available. Big changes were taking place in the early sixties, old reliable tuned reed systems were on the way out and proportional control was taking its place. But none of them worked, that's why you needed a disposable test aircraft like Phil Kraft's Ugly Stik and Don's Digester. Doug Spreng designed the servo circuit for the Digicon system and it was a revolution, orders of magnitude better than anything else. He never patented the circuit and everybody else in the business immediately copied it. In fact, you can take one of his original servos, change the plug and it will work perfectly in a system made today, the basic principle has not changed in 50 years. But the Digicon had a fatal flaw, the trim would change when you got further away from the transmitter, not much but enough to discourage the pattern fliers who bought it. Somebody came up with a modification to cure the problem but it was too late and Digicon folded.
DougSmith - 30/05/2015
The Ugly Stick is probably the most famous radio control airplane in history. Phil Kraft designed it to build fast and be used as a test plane for his digital radio control systems. But this plane wasn't the first test plane for digital radios. This distinction falls to the Digester [more pics 005-007]. While the Ugly Stick appeared in Grid Leaks in May of 1966, The Digester had made its debut in R/C Modeler in December of 1964. Don Mathes designed the plane to test his own radio system, the Digicon, so the title Digicon Tester was shortened to Digester. The Digester is a three channel plane and the Ugly Stick uses four channels. The plane must have impressed Phil Kraft somewhat for he used the airfoil for his Ugly Stick.
JimHales - 08/05/2017
Add a comment



* Credit field

The Credit field in the Outerzone database is designed to recognise and credit the hard work done in scanning and digitally cleaning these vintage and old timer model aircraft plans to get them into a usable format. Currently, it is also used to credit people simply for uploading the plan to a forum on the internet. Which is not quite the same thing. This will change soon. Probably.


This model plan (like all plans on Outerzone) is supposedly scaled correctly and supposedly will print out nicely at the right size. But that doesn't always happen. If you are about to start building a model plane using this free plan, you are strongly advised to check the scaling very, very carefully before cutting any balsa wood.


Terms of Use

© Outerzone, 2011-2018.

All content is free to download for personal use.

For non-personal use and/or publication: plans, photos, excerpts, links etc may be used, provided that full and clear credit is given to Outerzone with appropriate and specific direction to the original content i.e. a direct hyperlink back to the Outerzone source page.

Unauthorized use and/or duplication of this material without express and written permission from this site's owner is strictly prohibited. If we discover that content is being stolen, we will consider filing a formal DMCA notice.