71 replies to this topic

[Arthur Brown]

Sorry but that design demands a perfectly flat floor to stand upright and there is no way to tip it slightly into wind to keep the breaks away from the crowd. Would work well on a concrete base but not so sure about real conditions in a rough and tussocky meadow.

[digger]

6ft by 6ft rack that's got to be heavy once loaded with mortars.


here's my design so far for my 4" mortars, i could put more mortars in it but at least it makes it very portable and easy to store.



can anyone see any big problems with this design before i get a load made up.

I would tend to go for racks with a single row of tubes at 4", you can then use an end plate/bars to lock several of them together. This will allow you to put some angle between the racks of tubes so that you are not just firing all of your shells into the same ish location in the sky.

P.S. One thing to remember is that if you are using fiberglass mortars then they are wider at the base than they are at the top.

Edited by digger, 24 May 2009 - 07:56 PM.

[Mixologist]

I would be more inclined to have a couple made up to destruction test... rather than a load.... then if there is a failiure that renders them useless you havent lost as much money.

[Mixologist]

Are the tubes flush with the floor there? They look like the racks are on legs.....

Starting to look better though....

[Mixologist]

Plus i`ll just add that any type of adjustable feet you may have will possibly be ok on hard standing but on anything soft,,,, even dry hard grass,,, will sink in as soon as the first mortar fires and could make your rack take a new angle and possible a dangerous one. I would abandon this idea all together if i were you!

[Mixologist]

Firstly in my opinion...

All tubes should sit as close tot he floor as possible, if they are suspended in the air they will only try and punch through the rack to get to the floor.... for every force there is an equal an opposite and all that so if needs something hard to punch against.

The feet, yes if you had wider ones would help but the base of the rack if you best `plate` you could have, try getting that to tilt instead maybe....

[digger]

ok added a wide bar on bottom to support mortars and as close to the floor. also added wider feet. anything else i could improve on.

Why the need for feet at all? Every rack I have seen hasn't had them, just a simple plate right across the bottom would suffice (no more than 2mm for a 100mm ish span).

When you bolt a couple of racks together it will become a very strong structure. If you are only using one rack then simply knock in a few stakes to support it.

Have a think about how many mortars you put in each rack. You may have to carry them by yourself (my wooden racks with 6 mortars are pretty heavy). It is easy to work out the projected weight before construction from your cutting/material list.

[Mixologist]

As i`ve said before and Digger has said now, just loose the feet unless you really really want them, i can only see them getting in the way when stacking/transporting etc....

As for how many per rack... I can carry mine on my own without much problem (constructed from wood and thick walled cardboard tubes) and they are as follows:

2.5`` 10 tubes per rack
3`` 5 tubes per rack
4`` 4 tubes per rack / 3 tubes with fan racks / some wide 2 fanned racks
5`` 3 tubes per rack
6`` 1 tube in a rack vertical with 2 x 5`` fanned each side

These are luggable, wou could reduce the weight with thin walled tubes, but adds to the risk in my opinion.

[pyrotrev]

That's looking better. It's worth pointing out that in the event of a tube blowing, it generally goes wrong somewhere in the middle of the tube, so it's worth not putting too many cross bars there, as they will get more force on them.