Air starting 24mm composite motors off rrc3?

[Not Quite Nominal]

What’s a reliable way to start Aerotech 24mm motors off an RRC3?

I am thinking of either an E30 Blue Thunder or F39, at BT motors tend to light quickly.

Are there igniters that are sufficiently low current to fire off an RRC3/9V that are also hot enough to reliably light off a composite motor?

Will Firstfire Minis or Estes Sonic igniters light off the RRC3/9v, or even RRC3/1S Lipo?

 

[cerving]

I've airstarted 24mm AT motors, but not with a RRC3. My advice would be: 1) Yes, use the BT motors; 2) Don't use a 1S Lipo or (especially) a 9V, go with a 2S Lipo; 3) the FirstFires will work, but a bit of extra dip won't hurt.

 

[rharshberger]

I have used homemade igniters made from both 36 and 40 gauge nichrome wire from https://jacobs-online.biz/nichrome_wire.htm
and had success using both RRC3 (9V and 2sLipo) and Eggtimer Quantums. The dip for the igniter was a Firefox non-conductive pyrogen with an overdip of PyroMag (not sure if FireFox is even still in business as their website is unavailable), the other pyrogen I use straight is BKNO3-V, as its heat sensitive enough to light before the 40ga wire burns through.

 

[Not Quite Nominal]

I've airstarted 24mm AT motors, but not with a RRC3. My advice would be: 1) Yes, use the BT motors; 2) Don't use a 1S Lipo or (especially) a 9V, go with a 2S Lipo; 3) the FirstFires will work, but a bit of extra dip won't hurt.

Thanks! That's what I was wondering. A few questions:

Can you check my math? If (Battery Voltage)/(Igniter resistance + Battery Internal Resistance) > (Igniter all-fire current), it lights. In the case of an Estes Sonic off a 2S LiPo, that's 7.2V/(1.6 ohms + basically nothing) = 4.5A, which is greater than the all-fire current of 3.5A.

Battery selection:

• A 500mAh 20C battery theoretically can supply 10A, so it would be fine
• 9V is a bad idea because the internal resistance (1-2 Ohms) limits current output
• 1S Lipo is a bad idea because it doesn't have enough voltage.

Igniter selection:

• Estes Sonic is 3.5A all-fire, 1.6 ohms. Will it light an Aerotech BT motor?
  
• FirstFire Mini fits inside most 24/40 reloads and E30 single use. Will the 2S Lipo light it?

I have used homemade igniters made from both 36 and 40 gauge nichrome wire from https://jacobs-online.biz/nichrome_wire.htm
and had success using both RRC3 (9V and 2sLipo) and Eggtimer Quantums. The dip for the igniter was a Firefox non-conductive pyrogen with an overdip of PyroMag (not sure if FireFox is even still in business as their website is unavailable), the other pyrogen I use straight is BKNO3-V, as its heat sensitive enough to light before the 40ga wire burns through.

Dip: Totally unfamiliar with dipping. Of the various dips on the market, which ones would you use? Would you start with a bare wire, or augment an MJG Firewire?

 

[Nytrunner]

Estes Sonic is 3.5A all-fire, 1.6 ohms. Will it light an Aerotech BT motor?

Estes G80T used sonic igniters, and they were just rebranded Aerotech

 

[cerving]

Thanks! That's what I was wondering. A few questions:

Can you check my math? If (Battery Voltage)/(Igniter resistance + Battery Internal Resistance) > (Igniter all-fire current), it lights. In the case of an Estes Sonic off a 2S LiPo, that's 7.2V/(1.6 ohms + basically nothing) = 4.5A, which is greater than the all-fire current of 3.5A.

Battery selection:

• A 500mAh 20C battery theoretically can supply 10A, so it would be fine
• 9V is a bad idea because the internal resistance (1-2 Ohms) limits current output
• 1S Lipo is a bad idea because it doesn't have enough voltage.

Igniter selection:

• Estes Sonic is 3.5A all-fire, 1.6 ohms. Will it light an Aerotech BT motor?
  
• FirstFire Mini fits inside most 24/40 reloads and E30 single use. Will the 2S Lipo light it?

Dip: Totally unfamiliar with dipping. Of the various dips on the market, which ones would you use? Would you start with a bare wire, or augment an MJG Firewire?

Just about any 2S Lipo will light a FirstFire Mini. I don't think the Estes Sonic igniters will light an AP motor without being dipped, but one of the PS II igniters will easily light a 24mm motor and they're easy to fit in the little slots too. I've used both of them for airstarts, with one of the skinny 300 mAH 2S Lipo's that Hobby King sells.

Firefox has a good selection of dips, you can also search for "pyrogen" on the Forum and find a number of them if you feel like making your own.

 

[rharshberger]

Thanks! That's what I was wondering. A few questions:

Can you check my math? If (Battery Voltage)/(Igniter resistance + Battery Internal Resistance) > (Igniter all-fire current), it lights. In the case of an Estes Sonic off a 2S LiPo, that's 7.2V/(1.6 ohms + basically nothing) = 4.5A, which is greater than the all-fire current of 3.5A.

Battery selection:

• A 500mAh 20C battery theoretically can supply 10A, so it would be fine
• 9V is a bad idea because the internal resistance (1-2 Ohms) limits current output
• 1S Lipo is a bad idea because it doesn't have enough voltage.

Igniter selection:

• Estes Sonic is 3.5A all-fire, 1.6 ohms. Will it light an Aerotech BT motor?
  
• FirstFire Mini fits inside most 24/40 reloads and E30 single use. Will the 2S Lipo light it?

Dip: Totally unfamiliar with dipping. Of the various dips on the market, which ones would you use? Would you start with a bare wire, or augment an MJG Firewire?

As long as the Firewire will fit through the nozzle it can be augmented, if not its make your own using the wrap method. Quickburst, Magnalite, most igniter dips are sensitive enough, here lately BKNO3V has been my goto dip. I have been known to "paint" a bit of pyrogen in the top of the slot of the 24mm Hobbyline reloads to help increase odds of ignition (fact or my opinion not sure which but it has seemed to work).