Lift charge in various sizes of shells! :)

[TheGandalf]

Hello.

I am looking for a form where you can see how many grams of lift charge to be used in the various sizes of shells.

Is there one?

//TheGandalf

[wizard7611]

This is not something that cannot be answered easily. There are a number of variables that are thrown into play. It's best to just go with an ounce per pound(16 grams per 453.592 grams).

Edited October 25, 2015 by wizard7611

[MadMat]

As Wizard said, there are a lot of variables. I have heard people on here say that a rule of thumb was 10% of the weight of the shell, rounding up for good measure. Your best bet is to make some dummy shells approximately the average weight of your shells and experiment. Start off with the 10% rule and go from there.

 

Actually, one of the first things I do with a new batch of BP is fire off a dummy shell. Since I have the advantage of a water tower nearby, I have a "gage" with which to judge the height of the dummy shell. If you aren't that lucky you can use a stop watch and the time the flight. Either way you know right away if your new batch of BP is up to snuff.

Edited October 25, 2015 by MadMat

[OblivionFall]

I think it's something like 1/8th of the shell's weight or 1/16th depending on how hot your BP is.

 

Try experimenting yourself. I think about 1/12th would be a good halfway point.

[Mumbles]

I think it's something like 1/8th of the shell's weight or 1/16th depending on how hot your BP is.

 

Try experimenting yourself. I think about 1/12th would be a good halfway point.

 

If you don't know and can't be bothered to look anything up, you probably shouldn't be giving advice. I do appreciate the rare departure from talking about flash and salutes though.

 

As others have alluded to, there really isn't a good hard and fast rule for amount of lift. Most rules of thumb are based upon commercial BP. If you use homemade BP, this may change things. How well the shell fits in the gun, as well as black powder grain size will also affect things.

 

Personally, I generally use 10% of the shell weight of 4FA black powder for shells under about 1lb. I use 6.25% (ounce per pound) of 2FA for shells over about 1lb. If you get into even heavier shells, I use 1oz per pound up to 10lbs, then 1/2oz per pound for every pound over 10lbs. IE a 20lb shell would have 15oz of lift.

 

There's a table here, about halfway down that shows some typical lift charges, which is transcribed from Pyrotechnica IX, more commonly known as the Fulcanelli Papers or Articles. http://bangkokpyro.com/shell-building.php

[Arthur]

The lift mass is a feature of your shell design, and therefore best determined by you!Take some good guesses and the best figures from the literature, then test it and alter it to suit. Ultimately the right lift is when things work with the burst at the right part of the ballistic trajectory, which is also defined by the break delay fusing.

 

The mass of the shell gives you a clue but very light Poka shells may need more lift that a normal warrimono.

[Ubehage]

I only make 2", 2.5" and 3" shells, and I usually use 10% of the shell weight.

For 3"-shells it's definitely overkill. But it gives a nice cannon boom

[psypuls]

my favorite lift charge weight for all shells is 7.5% hot bp granules

but I do change it a lot just for fun. 6%,9%,12%.. So keep to around that percentage if your bp is great.