An "R"-powered rocket build

Was also given a recommendation for this switch which I also like.

However the simplicity of the robotic switch along with it being bulletproof should make it perfect for this rocket.

Chuck C.

I’ve had one of these rotary switches fail during ground testing. And have heard of other reliability issues for this switch on this forum.

If you decide on this switch, solder the battery + lead to terminals 2 AND 3. And solder the load to terminals 1 AND 4. That way, you have a redundant contact. You can even put a dab of black epoxy over part of the numbers to get ‘0’ for off and ‘1’ for on.

Rail Dawg said:

Was also given a recommendation for this switch which I also like.

However the simplicity of the robotic switch along with it being bulletproof should make it perfect for this rocket.

Chuck C. View attachment 381370

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I’ve had two of these fail just from cycling them while bench testing.

Rotary switches are famous for failing under high Gs (rocketry) as that's not what they were designed for. I am using the PCB screw switches on my L3 build and I'm confident that they will hold up even if things don't go as planned. People swear by them and I see why - simple, cheap, and reliable. Love the build so far, keep up the great work and wonderful updates!

That rotary switch for this project....NO! for too many reasons.

What CJ said!

Rotary switches are fine for slower flights but I would avoid them near or above Mach.

https://www.rocketryforum.com/threads/rotary-switch-failures.138371/

There are better more hardy switches out there:
https://www.fingertechrobotics.com/proddetail.php?prod=ft-mini-switch

I have abandoned those plastic rotary switches altogether. Seems like even the smallest bit of overtorquing with the screwdriver cracks them. I have at least one where I have to wiggle the screwdriver to find the on position. As soon as time permits, that is getting replaced by a metal key switch.

I will add to the chorus advising against the rotary switch. I had the most issues with the leads being fragile and breaking off, particularly if the switch was mounted in the switch band and then led to wires on a sled that slid in and out of the AV bay. I have only been successful with that switch by mounting it to the sled so the wiring all stays in one place and jumpering the leads as recommended by NickG above. If you've gone that far, you may as well just install a Missileworks or equal screw switch or the combat robotics switch as recommended by Crazy Jim.

I use the missileworks altimeters and screw switches, never had any issues, but I have not gone over mach yet
I 3D print my sleds

I don't know of anything bad that mach could do to a screw switch. They are probably the best bet just for switch reliability. The only downside is that once you are out of audio range of the altimeters, you can't visually tell if the altimeter is on.

Bat-mite said:

I don't know of anything bad that mach could do to a screw switch. They are probably the best bet just for switch reliability. The only downside is that once you are out of audio range of the altimeters, you can't visually tell if the altimeter is on.

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Someone needs to build an amplified beeper that takes the output from the various avionics and sends it to a loud speaker set in the body tube.

Rail Dawg said:

Ok I like this “combat robotic switch”.

Looks like it can take a beating and those wire connectors are solid. I’m going to order these and see how they work.

Thanks for this and to the others with their good ideas.

Chuck C.

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Chuck,

That Combat Robotic Switch looks like it will fit the bill, nicely !

https://www.fingertechrobotics.com/prodimages/connswitches/Servo 2013-04 Mini Switch Review.pdf

Any motor static test data yet ?

Dave F.

How does a switch know how fast it's going?

jderimig said:

How does a switch know how fast it's going?

Click to expand...

How does a plastic nose cone know how fast it's going when it starts to melt at Mach 3?

jderimig said:

How does a switch know how fast it's going?

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Rocksim, of course . . . LOL !

Dave F.

Ez2cDave said:

Chuck,

That Combat Robotic Switch looks like it will fit the bill, nicely !

https://www.fingertechrobotics.com/prodimages/connswitches/Servo 2013-04 Mini Switch Review.pdf

Any motor static test data yet ?

Dave F.

View attachment 381445

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This one has been flight tested on some wicked fast projects. It also fits in a 24mm MD rocket lol. It was recommended to me by Crazy Jim and others. I value flight tested.

Steve Shannon said:

Someone needs to build an amplified beeper that takes the output from the various avionics and sends it to a loud speaker set in the body tube.

Click to expand...

Why not just transmit it to a cell phone ?

If you want "bleeding ears" these buzzers are LOUD !









Dave F.

Only 2 grains of the Q motor have been made so far Dave. Going to make 3 more next week and the other 10 in the couple months ahead.

Will test one of the Q's on a test cell.

Chuck C.

These switches were part of a lawn dart project that made it about 20" subsurface with a 4" diameter flat bulkhead as a boring bit, falling from about 8000'. The char on them is from a fire that burned the remaining bits and pieces inside the AV bay, a lithium fire. All of the surface mount pieces on the boards were torn loose from the impact. Nothing was left intact inside. Except these switches. If it did not feel like bad ju-ju, I might re-use them. They still work fine. Still smooth action, and with clear continuity.

These switches are great. Other screw type switches might be reliable in their contacts, but would they survive impact and fire? Seeing what happened to the pc boards after this event, the board based switches would not likely survive.

The fire from the batteries was an eye opener. The potential is there for an ignition source when fire danger is moderate to high.

Rail Dawg said:

Only 2 grains of the Q motor have been made so far Dave. Going to make 3 more next week and the other 10 in the couple months ahead.

Will test one of the Q's on a test cell.

Chuck C.

Click to expand...

Chuck,

Excellent . . . Looking forward to "real world data" on motor performance !

The motor is going to be 5 grains ?

How is the rest of the rocket coming along ? Pics ?

Have you received the Fin Can yet ?

Dave F.

Chris_H said:

These switches were part of a lawn dart project that made it about 20" subsurface with a 4" diameter flat bulkhead as a boring bit, falling from about 8000'. The char on them is from a fire that burned the remaining bits and pieces inside the AV bay, a lithium fire. All of the surface mount pieces on the boards were torn loose from the impact. Nothing was left intact inside. Except these switches. If it did not feel like bad ju-ju, I might re-use them. They still work fine. Still smooth action, and with clear continuity.

These switches are great. Other screw type switches might be reliable in their contacts, but would they survive impact and fire? Seeing what happened to the pc boards after this event, the board based switches would not likely survive.

The fire from the batteries was an eye opener. The potential is there for an ignition source when fire danger is moderate to high.

Click to expand...

The screw switches can take the G's of a high speed launch.
They just can't take that sudden stop at the end of a lawn dart flight. Yours did

Ez2cDave said:

Chuck,

Excellent . . . Looking forward to "real world data" on motor performance !

The motor is going to be 5 grains ?

How is the rest of the rocket coming along ? Pics ?

Have you received the Fin Can yet ?

Dave F.

View attachment 381493

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Yep 5 grains for both the Q and R.

Fin Can should be arriving this month. That thing is going to look awesome!

Am submitting the application to the C3RC (TRA Class 3 Review Committee) today for both LDRS 38 and BALLS 28.

Building a rocket is one thing another side is ensuring the paperwork is in order. Also that safety is kept as the #1 priority. Thanks to the good work of the C3RC the FAA Certificate of Authorization (COA) application is assessed for completeness. The C3RC also uses RockSim Pro to analyze the flights to ensure they comply with the FAR's (Federal Air Regulations).

Here's FAR 101.29(b) Class 3 rockets are rockets powered by "P" motors and higher.

Sec. 101.29(b) Class 3—Advanced High-Power Rockets.

When a Class 3—Advanced High-Power Rocket requires a certificate of waiver or authorization the person planning the operation must provide the information below for each type of rocket to the FAA at least 45 days before the proposed operation. The FAA may request additional information if necessary to ensure the proposed operations can be safely conducted. The information shall include for each type of Class 3 rocket expected to be flown:

(1) The information requirements of paragraph (a) of this section,
(2) Maximum possible range,
(3) The dynamic stability characteristics for the entire flight profile,
(4) A description of all major rocket systems, including structural, pneumatic, propellant, propulsion, ignition, electrical, avionics, recovery, wind-weighting, flight control, and tracking,
(5) A description of other support equipment necessary for a safe operation,
(6) The planned flight profile and sequence of events,
(7) All nominal impact areas, including those for any spent motors and other discarded hardware, within three standard deviations of the mean impact point,
(8) Launch commit criteria,
(9) Countdown procedures, and
(10) Mishap procedures.

Again thanks to the C3RC all of this is reviewed and suggestions made to ensure everything is in order.

Thanks!

Chuck C.

Chuck, do you mind starting a thread in the research section for the motor? I ask because I am curious of how its being made and what the process looks like. I've seen the Q motor that lifted the 3/4 Mercury Redstone but would like to see your R motor being made.

Hmmm, RockSim Pro is $1000 with yearly license fees

Rail Dawg said:

Only 2 grains of the Q motor have been made so far Dave. Going to make 3 more next week and the other 10 in the couple months ahead.

Will test one of the Q's on a test cell.

Chuck C.

Click to expand...

Q and R motor? think I missed something

jbr said:

Hmmm, RockSim Pro is $1000 with yearly license fees

Click to expand...

The TRA C3RC as part of their good work have that program. It's what they use to do the flight analysis.

Chuck C.

jbr said:

Q and R motor? think I missed something

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If all goes well the Q for LDRS 38 and the R for BALLS 28.

Chuck C.

0011001100 said:

Chuck, do you mind starting a thread in the research section for the motor? I ask because I am curious of how its being made and what the process looks like. I've seen the Q motor that lifted the 3/4 Mercury Redstone but would like to see your R motor being made.

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Give me some time if that’s ok. This thread keeps me busy but can at some point get a discussion going.

Thanks!

Chuck C.

Rail Dawg said:

Give me some time if that’s ok. This thread keeps me busy but can at some point get a discussion going.

Thanks!

Chuck C.

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Don't worry no rush. Was just curious as I've gotten into making my own (much) smaller motors and am always open to learning.