Summary 
 
	The Universal Flight Controller/Datalogger (UFC) is a small light- 
weight computer designed for multiple applications in the field of  
advanced model rocketry. This NAR research & development report  
describes the project from initial conception, through the design and  
prototyping stages of both the computer hardware and software. In  
addition, several possible applications and experiments are described  
and one example is used to gather actual results. 
 
	The primary goal of this project is to build a multi-purpose  
system that is easy to program and operate by the average person without  
the need for a computer or electronics background. Another important  
requirement is a good cost/performance ratio compared to using several  
commercially available systems (timers, dataloggers, altitude payloads,  
etc.). Secondary goals include: small size, low mass, expandability and  
reliability. 
 
	The use of electronic payloads in model rocketry has become more  
popular over the years with the availability of higher power motors. An  
early idea was a transmitting beacons which uses a radio signal to  
locate a model rocket after landing; a similar device uses a loud  
audible "beeper". The small size of these "passive" electronic payloads  
makes them easy to lift using small motors and simple models. However,  
more complex designs are needed to control aspects of a flight or to  
record data during the flight.  
 
	Two popular uses of "active" electronic payloads are the staging  
timer and the ejection timer; they typically use low-cost timer chips  
but some are based on more accurate crystal clock designs. These timer  
applications are most useful in larger model rockets which use composite  
rocket motors. Unlike the "black power" motors, composite motors need an  
active ignition system to ignite an upper stage at a pre-set time. Also,  
most composite motors are available in just three widely spaced ejection  
delays that may not be accurate enough for a safe ejection near apogee.  
A timer circuit is often used to trigger an ejection charge at a pre-set  
time that is different than the motor's ejection delay. Often they are  
used as a redundant backup for models with a great deal of money and  
time invested in them. 
 
	As advanced high power rocketry is becoming more popular and  
reusable technology is bringing down the price of larger motors,  
rocketry experimenters are finding it easier to lift more complex  
payloads. Recently, altimeters and dataloggers have become popular,  
especially with hobbyists who have a background in electronics. However,  
the typical rocket flyer may find it too difficult to work with a  
computerized payload which requires custom computer programming. Other  
than the simple one-purpose payloads, a project which requires multiple  
inputs, multiple outputs and moderate data logging speed is beyond the  
scope of the rocketry hobbyist.  
 
	At the present time, someone interested in designing a data  
logging experiment would first locate a microcontroller capable of  
handling the number of inputs and the sampling rate needed. The board  
would have to be reasonably small and light-weight, and operate from  
low-power batteries for a period long enough to prepare, fly and recover  
the model, then retrieve the data and permanently store the results. The  
system would need to be low-cost (under $200) and further reduce the  
cost and complexity by incorporating other electronics (staging timers,  
ejection timers, etc.) into the main computer system. Then, most  
difficult of all, the system would require no computer programming  
beyond simple instructions and would require no special equipment (such  
as an EPROM programmer). Also, the experimenter would need a program  
capable of analyzing the raw data by converting it to an understandable  
format (graphs, charts, etc.).  
 
	 As the preceding paragraph describes, most rocketry enthusiasts  
quickly realize that computerized data logging and controlling is beyond  
their capabilities. Unfortunately, many are missing out on one of the  
most challenging aspects of advanced model rocketry.  
 
	This R&D project describes the design a universal computerized  
payload which makes it easier for the average person to experiment with  
active electronics in model rocketry. The result is a hardware and  
software prototype which could be further refined and offered as a low- 
cost kit.