Clustering Redline and Mojave Green

[AlexBruccoleri]

Does anyone have any tips for clustering Redline propellant or Mojave Green? I find Blue Thunder lights easily but I wanted to give other propellants a try. Thanks, Alex

 

[rharshberger]

BKNO3-V igniter pyrogen (available from Quickburst as ProCast), paint a little at the top of the topmost grain, then use a igniter made with same pyrogen. The stuff will light dirt if given half a chance, and lighting greens and older reds can be a bit harder.

ProCast Order Page – QuickBurst

 

[jimzcatz]

Pyrodex pellet in the top grain, light with any low current ematch.

 

[AlexBruccoleri]

Pyrodex pellet in the top grain, light with any low current ematch.

I should add some details. This is a cluster of DMS G motors. I cannot paint the grains.

 

[dhbarr]

When you do this, make sure a) your igniters all have similar resistance, b) your launch system can provide plenty of amps, and c) your pyrogen is consistent and even.

Longer leads draped from above and away from the fins can be useful for allowing unlit igniters a little extra time to get things going.

 

[jimzcatz]

Then you need to change your plans. Use reloads or DMS blues. A single ematch alone won't light most motors

 

[AlexBruccoleri]

When you do this, make sure a) your igniters all have similar resistance, b) your launch system can provide plenty of amps, and c) your pyrogen is consistent and even.

Longer leads draped from above and away from the fins can be useful for allowing unlit igniters a little extra time to get things going.

That is a good idea!

 

[jimzcatz]

Plus don't try 6 at once first time. Build up to it. Just friendly advice.

 

[AlexBruccoleri]

Then you need to change your plans. Use reloads or DMS blues. A single ematch alone won't light most motors

I was planning on using a standard first fire igniter junior and maybe add some pyrogen above or below. An ematch seems precarious.

If my approach sounds dubious, I will definitely change plans.

 

[Banzai88]

Yeah, I've flown mostly reds and greens for the last year and a half from 29 hobbyline up to 54s. Greens take a lot of heat to get lit off reliably, and reds (even brand new just assembled within half an hour of launch) have a tendency to chuff (even if only a little bit).

Oddly enough, the little green AT 29mm hobbyline is a VERY consistent green that lights easily every time. Other than that, not so much! I've had greens eat some of the best starters and STILL take time to come up to pressure and make you wonder if you pressed the button or if the igniter even worked.

Reds tend to light, pop, chuff, build pressure.....THEN go ZOOM. Inconsistent as heck. Given any 3 of the SAME reload on the SAME day, they'll each light slightly differently. I've done it several times and have enough video of my launches with reds to know that the only real consistency with them with lighting is inconsistency.

Based on my experience, I would never try to cluster reds and greens together, of any nature, even with igniter enhancement.

Maybe you can find something that works, but work up with doubles first until you find that approach.

 

[AlexBruccoleri]

Yeah, I've flown mostly reds and greens for the last year and a half from 29 hobbyline up to 54s. Greens take a lot of heat to get lit off reliably, and reds (even brand new just assembled within half an hour of launch) have a tendency to chuff (even if only a little bit).

Oddly enough, the little green AT 29mm hobbyline is a VERY consistent green that lights easily every time. Other than that, not so much! I've had greens eat some of the best starters and STILL take time to come up to pressure and make you wonder if you pressed the button or if the igniter even worked.

Reds tend to light, pop, chuff, build pressure.....THEN go ZOOM. Inconsistent as heck. Given any 3 of the SAME reload on the SAME day, they'll each light slightly differently. I've done it several times and have enough video of my launches with reds to know that the only real consistency with them with lighting is inconsistency.

Based on my experience, I would never try to cluster reds and greens together, of any nature, even with igniter enhancement.

Maybe you can find something that works, but work up with doubles first until you find that approach.

Okay this is what I was looking for. I will cancel my plans and just stick with blue thunder for now. One clarification, I was not planning to light both greens and reds in the same flight. This is for a 3-engine cluster.

 

[jimzcatz]

3 motor cluster should be doable on the ignitors included with the motors. Just use a good relay launch system, which most clubs will have.

 

[AlexBruccoleri]

3 motor cluster should be doable on the ignitors included with the motors. Just use a good relay launch system, which most clubs will have.

Do you mean with red and green or blue thunder?

 

[jimzcatz]

I wouldn't mix them, but 3 motors of red or green should light OK

 

[Banzai88]

Ok, I mis understood and thought you were mixing in the cluster.

I agree with Jim, clusters of LIKE motors should be OK, but launch a few singles first to get a 'feel for how they light so you get some idea for the cluster light off event.

 

[dhbarr]

If you ever feel real froggy, six-around-one with a blue in the center and whites, greens, and reds opposed should in theory be doable.

 

[heada]

If you ever feel real froggy, six-around-one with a blue in the center and whites, greens, and reds opposed should in theory be doable.

I did the opposite. 6 blues with a central white. 6x F42T 1x H180W in a LOC Ultimate. The blues come up to pressure and get everything going immediately and the white comes up to pressure about 50 ft above the ground. LONG leads (6ft) on hand dipped Magnelite igniters with a freshly charged battery on a relay box.

For red/green clusters, I'd consider clusters of the same type (all red or all green) but not mixing the types on the same rocket.

 

[ZEDL1]

I'd be relatively comfortable with either all green or all red ground started, with the alternate colour being airstarted.
That said, either colour may exhibit differing ignition behaviour on any given day, as was mentioned. I'm Canadian, hence the "u" usage.

 

[StreuB1]

I use ematches with a small sliver of BT propellant taped to the match.

I bought a D21T reload kit (2 grains) and carve slivers off of those. Lasts a long time.

Lights (7) Dark Matter / Metalstorm motors (H115's and J430) all at once with no issues.

Will be trying the same rocket on a J570W central and (6) radial G74W Economax's this spring.

 

[heada]

I use ematches with a small sliver of BT propellant taped to the match.

I bought a D21T reload kit (2 grains) and carve slivers off of those. Lasts a long time.

Lights (7) Dark Matter / Metalstorm motors (H115's and J430) all at once with no issues.

Will be trying the same rocket on a J570W central and (6) radial G74W Economax's this spring.

Check to see if the ematch heads will fit into the G74W nozzle before the launch. Some of the nozzle openings on the smaller motors aren't big enough for the head of an ematch.

 

[StreuB1]

Check to see if the ematch heads will fit into the G74W nozzle before the launch. Some of the nozzle openings on the smaller motors aren't big enough for the head of an ematch.

Good call! Will check tonight.

 

[fyrwrxz]

When you do this, make sure a) your igniters all have similar resistance, b) your launch system can provide plenty of amps, and c) your pyrogen is consistent and even.

Longer leads draped from above and away from the fins can be useful for allowing unlit igniters a little extra time to get things going.

^This! You've got the length of the rail (at least) to get everybody playing well with each other.