Added lift experiments?

[tustinfarm]

With the 60g total composition limit for "proper" 1.4g consumer cans, I wonder if the manufacturers compromise on minimizing the lift charge, to allow for the maximum effects content in the breaks. I am curious of anyone has experimented by adding a gram or two of extra black powder to increase the height for the breaks. Seems like adding that externally to the bottom of the mortar would be all that is needed, i.e. no doctoring with the shell itself. From a science standpoint the limiting factor would be the extra pressure surge, and whether the shell can withstand that without damage that leads to a flower potting event, or worse (!).

[topshelfpyro]

It may get it out of the tube faster, which, similar to a longer tube, will get it a bit higher. the real issue is the time fuse which is about 1.5 seconds for cans. People like the low breaks because they look "big". Even 1.4 pro 62s are breaking significantly lower than before. At least in a comparison between 2018 production and 2022/2023 production. It's infuriating.

[BMoore]

Yeah, the time fuse would be your limiting factor. You might be able to get a little more height due to increased velocity, but it would probably be barely noticeable. A lot of work for minimal gain in my opinion. Some manufacturers seem to be skimping on lift, but there are still plenty of good consumer shells out there. Along those same lines, I wonder about the wasted space under the cap on most shells these days. Remove that black cap and there is usually a dead air space. That wasted cardboard is adding weight and probably affecting height due to to off-balancing. Would cutting down that top gain you anything? Again probably too much work for too little gain.

[RalphieJ]

I would not chance dropping loose BP in the bottom of the mortar due to the chance of having it firing sooner than the lift charge, causing a low or even a ground break. Just open the bottom of the lift cup and add more.......

[BMoore]

I would not chance dropping loose BP in the bottom of the mortar due to the chance of having it firing sooner than the lift charge, causing a low or even a ground break. Just open the bottom of the lift cup and add more.......

Agree! I missed that part of the original question. If you are going to experiment with adding BP, add it to the lift cup, not the bottom of the mortar.

[PyroFL]

I’ve experimented a bit with this under controlled conditions. You’re right that the 60g total composition cap means manufacturers often cut lift to maximize break content. That does affect height but the bigger issue tends to be timing vs. trajectory.

A couple things I’ve found:

- Adding lift inside the cup (as others said) is safer than loose BP under the shell. The risk of pre-ignition from a stray ember or residual spark in the tube isn’t theoretical it happens
- Even 1g of added lift can change the height slightly, but the delay fuse doesn’t adjust with it. If you’re gaining 15–20 feet in altitude, but still have a 1.5s fuse you’re just shifting the break point a bit, not really “fixing” anything. You’re still stuck with timing optimized for the original lift
- You can test timing height curves by taping delay fuses to dummy weights and lifting them to check break altitudes. But for real world use unless you’re custom fusing or making your own canister inserts, the gains don’t usually justify the risk or hassle
- On the point about the caps and dead air space that’s a real observation. Some caps add unnecessary weight and while it doesn’t dramatically lower height it does throw off balance and can affect flight path consistency, especially in lower quality shells

Bottom line modifying lift can teach you a lot, but the benefits are marginal unless you’re also adjusting delay or working with custom or homemade shells. For most consumer shells it’s probably not worth the added risk or time unless you’re doing a deeper study or working toward pro effects.

[tustinfarm]

All, I really appreciate all of the useful information in the replies...I hadn't thought about the stray spark issue hitting loose BP like that, as well as the fact that the timing fuse can't be altered. So my takeaway from this is to keep things simple and leave well enough alone. Besides, I'm too lazy to spend all that time slicing open the lift cups and then adding extra BP.