Update Available

The App Store approved my latest update yesterday. This adds a motor look-up option to the Altitude Prediction->Data Assistant screen. It also fixes a minor issue on the Static Pressure Port calculator screen.

Here’s a screen shot from the motor look-up screen.

App Update – Body Tube Lookup for Altitude Prediction

I added a body tube look-up feature to the Altitude Prediction calculator. There is a new button on the Data Assistant screen which will provide a list of tubes to pick from. After selecting a body tube, the tube’s diameter and area will be populated back to the Data Assistant screen. I’m currently working on motor selection option, which should be finished soon.

Update Available

This update adds a few new features to the altitude prediction calculator. It will display the motor class percentage and thrust to weight ratio once a calculation is made. If the thrust to weight ratio is more than five the display is green. If less than five it is red. It will warn if the thrust ratio is less than five.

Since this calculator assumes a static drag coefficient, it will warn the user if the flight is transonic. Once a flight becomes transonic, the drag coefficient increases rapidly. For transonic flights, a static Cd could result in less accurate results.

The two warnings can be enabled or disabled by the user from the app settings.

Update is Available

The update containing the altitude prediction calculator is available. Enjoy.

Update re-submitted

I just discovered a bug in the ejection charge calculator. If you change the pressure to something other than psi, the initial calculation of force and bp amount will be wrong. Subsequent calculations will be correct. I fixed this and re-submitted the binary. Sorry for the delay.

Update coming soon

I submitted the update last night. It’ll probably be available within the next five days. This update contains the new altitude prediction calculator, as well as a few usability improvements.

Here is a screen shot.

Future Update Plans

I’m currently working on an altitude calculator based on the Fehskens-Malewicki solution for model rocket motion equations. This will show burnout velocity, burnout altitude, coast altitude, and coast time. One of the challenges is figuring the best way to put so much stuff on one tiny screen. Another is deciding a good way to select rocket motors and/or manually enter motor information. I’m ‘hoping’ to have this out to the App Store within a couple weeks.

A few other updates in the queue are:

• I plan to update the thrust to weight calculator allowing reverse calculation to show the ratio based on a given weight and thrust.
• Tint required fields to improve usability.
• Add more commonly used units for wind speed for the Drift Distance calculator.
• Update information on the Parachute calculator.

Update is now available

The update was approved and made available in the App Store. Below are screen shots the parachute and ejection charge calculators.

Feature Update Submitted

I just submitted a new update to Rocket Calculator. It should appear on the App Store within the next week.

What’s new:

• Added option to print or email calculation results.
• Added a spill hole option and Cd override to the parachute/descent rate calculator.
• Added amount of force produced and number of shear pins needed to the ejection charge calculator. You can also override the force value, and it will re-calculate the pressure and BP amount.
• Add references to the individual calculator info pages. These were in the ‘Sources of Research’ section already, but this makes it easier to match up the references to each calculator.
• Usability improvements.
• Fixed chute diameter rounding issue on parachute calculator.

Here are a couple screen shots of the updated calculators:

Holiday Sale!

I’m running a holiday sale from today to the 1st of January.