# eCalc - the most reliable RC Calculators on the Web for electric Motors

Multi Rotor Fans Club Lithium-Polymer Peak Charger Circuit Diagram - Nightly This circuit was developed to charge the Lithium-Polymer cells used in a model aircraft. Lithium-Polymer cells are incredibly lightweight compared to Ni-cad battery packs of the same voltage and amp-hour rating. Their only drawback is that they require a rigid charge and discharge regime to achieve maximum life. Circuit diagram: They should be charged using a constant-current, constant-voltage method, which stops the charge once the current has dropped to about the C/10 rate. REG1 and transistor Q2 form a current-limited voltage regulator. When the battery voltage reaches about 8.4V, the regulator limits any further voltage increase, as set by VR2. The charger is set up as follows: It to 12V DC and place a digital voltmeter between the output of REG1 and the negative output for the battery pack. The circuit should now charge your battery packs to within 97% of their rated capacity. Finally, note that in most cases, REG1 will need to be fitted with a heatsink.

Mon Drone | Tout savoir sur la fabrication d'un drone DIY FPV Monkey - Nightly Spherical Parachute Patterns - Nightly This web page will produce patterns for hemisphere parachutes for model rockets. Instructions for constructing the parachutes can be found in the May/June 2000 newsletter of the Northern Illinois Rocketry Association. The article describes the construction of 12 inch diameter parachute with 8 gores and a 2 inch diameter spill hole. This web page will produce patterns for other sizes of parachutes. As you are considering the size of your parachute, keep in mind that a spherical parachute has twice the drag coefficient of a comparable sized parasheet style parachute that comes with most model rocket kits. Parachute shroud lines should be 1 1/2 times the diameter of the parachute. Patterns include a 1/4 inch seam allowance. Please check your print settings before printing the pattern.

Richard Nakka's Experimental Rocketry Site - Nightly Solid Rocket Motor Design SRM.xls is an MS EXCEL spreadsheet that takes user-inputted motor and grain geometry data and computes Kn over the duration of the motor burn, generates a pressure-time curve, a thrust-time curve, as well as performance parameters such as total impulse and delivered specific impulse. Motor performance data is also summarized for easy input into a trajectory simulation software, such as SOAR. Although primarily intended for designing motors using KN-Dextrose or KN-Sorbitol propellant, other propellants may be specified with user inputted propellant properties. Dec.21/13 716 kbytes Zipped EXCEL 2000 spreadsheet Freeware SRM.ZIP Version: 1.00 536 kbytes Zipped EXCEL 2000 spreadsheet Freeware SRM_RU.ZIP Russian Language Version 1.08 Mbytes Zipped EXCEL 97/2000 SRM-CASTELLANO.ZIP Spanish Language Version 550 kbytes Zipped EXCEL Motor Casing Design CASING.XLS Version 1.03 61kbytes EXCEL 5.0 spreadsheet Freeware Rocket Motor Igniter Design Units Converter EzAlt PDFCreator