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I would use the motor with the delay that has the lowest velocity at ejection. Failing that, I would probably use the +2 seconds delay after apogee. Alternatively, you could adjust the rocket mass to better suit one of the motors ejection delay.

If you wish to take OpenRocket to the next level, you could employ the Multilevel Wind add on. This allows you to enter in the wind direction and speed at the multiple altitudes which will (hopefully) help improve the accuracy of the sims. Not quite as graphically satisfying as RockSim Pro, but...

I would use an altimeter sled that is wide enough to slide into your payload bay with a light friction fit. The sled would preferably have bulkheads at each end so you can use plastic rivets through the body tube to secure the sled in place. Sampling ports can be drilled into the volume...

Without a relay driver circuit at the pad end, you will need to confirm what the minimum relay activation voltage is. If the voltage drop over the long switch cable is such that it reduces the relay switch voltage to below its threshold voltage, then this simple technique might be unreliable...

A battery is not required at the wired launch controller if your pad relays are activated by a suitable line driver circuit. You can feed your pad battery voltage back down a third conductor to your launch switch box. Yes, you do have a voltage drop over the low current switch circuit, but that...

If it is normal DD, then it's either NC shear pins shearing due to vigorous drogue deployment, altimeter fault or deployment charge wiring.

You do need to separate them physically and preferably use a nomex blanket or heat proof barrier between the packed glove tips to reduce the discharge from one igniting the other. Preferably, you would use charge canisters (vials or charge wells) to provide better isolation.

If you have OpenRocket, RockSim, or any other simulation software you can try using different chute diameters to achieve a descent rate of about 5-6 m/s. This will only provide a very rough estimate depending on the particular profile (flat, hemispherical, elliptical, etc) you chose and the...

I think there might have been an earlier thread about these fireworks controllers. I'm sure they would be fine, but I can't recall whether there are issues for rocket launching.

This was my first computer! Built from a kit. http://www.oldcomputermuseum.com/mini_scamp.html

This could be a very slippery slope! Arduinos can be very addictive. There are some very good Arduino reference texts and web resources with lots of interesting circuit and coding examples. Good luck and have fun.

Please provide a circuit diagram. Your description is a little ambiguous.

Yes, there is a reason to use a relay-based system. If you’re using a long field cable to control your pad box, particularly for a hybrid, and you have high currents flowing to igniters and solenoids, you can waste a significant amount of your battery power over the long field cable. Using...

I agree with both these recommendations. I’ve been using Teflon tape for several years on my Nitrous plumbing since I started with hybrids; as Norm suggested, just use it without any loose bits over the front of the connectors. I’m always using solenoid savers these days. I started with simple...

To answer your previous question: the CG will be closer to 3" from the leading edge of the fin root. Remember that 1 caliber for the Big Daddy is 3" (it has a body diameter of 3"). So, from my simulation of you modded BD, the CP is just behind the fin root. So your CG is 3" forward of that...

I do have the electronic schematics of the designs for the launch controller, pad boxes and the wireless adapter. I will dig into my design file archive and send them to you later when I get back down to my office. I might also have some spare silkscreened panels that I used for the front...

Most added masses will affect the CG, and consequently the stability margin. With the additional mass of a motor retainer and an adapter, you will likely move the CG closer to the CP. So, you will need to add the appropriate amount of mass to the NC to bring the CG back to a point where the...

Advanced recovery systems using electronics for single or dual deployment can easily be used with smaller mid-powered rockets. In fact, it's a good place to start this journey. There's no need to wait for HPR flights to get the experience.

I simmed the stock BD with the OP’s 29mm MMT, ply fins and an F20-4W motor added. It still had a cal of <<1.0, but with 110g mass added to the NC, it had a cal > 1.0.

Sim it in OpenRocket. Change the standard Big Daddy sim model to reflect your material mods and check its CG and CP. The Big Daddy is susceptible to added masses, particularly if they shift the CG further aft. Changing to a 29mm MMT and ply fins will most likely affect the stability. You can...