Brief:

RocketCalc v1.43 for PalmOS is an eight-function calculator for the PalmOS device. It uses commonly accepted formulae for delivering accurate calculations on your Palm-powered device. It is donationware, meaning you should be honest and send money to the developer in proportion to the going PalmOS utility market prices based on the application's usefulness to you.

Construction:
The software requires MathLib (if you don't already have it) and pRASP (a RASP file converted to PalmOS file format). It works on all PalmOS devices including the Treo 600. There are no warranties expressed or implied. Source code is not available.

There are eight programs with the utility:

1. The Altitude Calculator uses data from either one or two tracking states to calculate the altitude reached by a rocket. Three different methods of calculation are available: geodesic, vertical midpoint, and single station (elevation only).
2. The Ejection Calculator can tell you how much FFFFg black powder you need to pressure a cylinder, how much pressure a given FFFFg BP charge will result in, and how much force it will exert on the bottom of the nose cone (piston).
3. The Wind Drift Calculator calculates how far downwind you can expect a rocket to drift as it comes down on its parachute.
4. The Motor Info Calculator calculates the maximum weight a given motor can lift at any thrust-to-weight ratio between 2:1 and 7:1. It also allows you to beam the entire motor database, or an individual motor, to another PDA.
5. The Static Port Calculator calculates the required size of static air pressure ports for altimeter pressure sensors (using the 'one 1/4" hole for every 100 cubic inches of bay space' rule).
6. The Standard Atmosphere Calculator calculates the pressure, temperature, density, speed of sound, and equivalent air speed at any altitude up to 86km, using the US Standard Atmosphere (1976) model.
7. The Parachute Calculator can calculate parachute size, descent speed, or rocket weight given the other two variables. Cd is customizable too.
8. The Delay Calculator will tell you how much time will pass between motor burnout and apogee for a given rocket and engine combination, allowing you to figure out in an instant which delay you need. (pRASP will give you the same information, and also allows you to simulate up to two stages. The RocketCalc Delay Calculator is a simplified version that only allows one stage and uses simplified calculations to give you an instant answer.)

All eight calculators allow you to use just about any combination of units you like: inches, feet, meters, centimeters, miles, kilometers, pounds, ounces, grams or kilograms.

Not all the programs are useful to me--at least not yet. For example, I can't think of when I might use the Atmospheric calculator since I don't yet use altimeter-based deployments. But some of you who are serious about altimeter-based deployment will be glad you have this capability. A program I really like is the Ejection application. I found this software when I was trying to figure out by how much I needed to reduce the internal volume of a 4" rocket to get the NC to pop based on a fixed amount of FFFFg BP from an AeroTech G80-4T.

I found the loading and setup to be typical simple and reliable PalmOS fare. The pRASP database is big and you can use a custom version if you prefer as you make it and convert it yourself.

The developer put a lot of thought into the basics of the application and it shows. Instructions to install and how to use are clear and concise.

I use RockSim v7+, but I don't bring my laptop to the launch with me. I do bring my Treo 600 with me though and having it loaded with the RocketCalc package is very helpful and useful. It is a must have for PalmOS users! If you have a PC running RockSim and you want to bring an excellent calculator with you then get a new or used (Palm V or better) Palm and load it up.

Summary:
PROs: Good user interface with well placed pick boxes and use of stylus is required. The Treo 600 users will not be able to use the multi-directional navigation button but everything else works great.

CONs: None.

There are other calculators that are available from this developer including: pRASP (can be used standalone) for up to 2 stages, CPcalc which is a Barrowman Center of Pressure calculator, Motor database (for pRASP) and a Neutral Point calculator for boosted gliders.

Overall Rating: 4 out of 5