New to hybrids

[mark.f]

With the right jellybean parts a maybe one or two specialized ones, you could use DTMF over radio...

[Juggernaut12121]

I'm pretty bad with circuitry, otherwise DTMF sounds preferable. I finally found a small rf transmitter that has pretty good reports and is cheap. I actually went to menards and practically built the thing XD
I wish I had taken a few pictures so that you all could critique the design. Anyhow I wanted to know what a few things mainly about the pilot area. What's a good bumper to use? I saw a few pictures of this sort of rubber thing but I never got a name. Also what's a good length to use on the housing/how far should the piston open? I've heard 1.5" was supposed to be a good distance but I'm not too sure how much the backstop will compress. And finally, what's a good way/length to select for the nipple to be used as the barrel seal? I've played with it a little and it seems like you could ground out the back end of the flat area in a 2"x1 1/2" bushing so that you could thread it in from that opposite end, and then full the area with epoxy, but I'm not sure this will work.

[mark.f]

It's mainly just for range and flexibility that I suggested DTMF, being that you can use FRS transceivers (20-30 for a pair) and get very respectable range... however, being that you obviously want to be able to see your cannon and what's downrange before you shoot it, not that much is required in the first place.

[Juggernaut12121]

More completely noobish stupid questions, is it fine to drill and tap galvanized pipe? It seems like the stuff is too thin for the threads to take root very well. Should I try and tap into a coupling or a fitting rather than the actual pipe? And I've seen these rubber gasket type things that people have been using for bumpers (MrC, Spudblaster) (and I think I might've asked this already) but I never caught a name for them or seen them in the store.

[noname]

I had a hybrid firing a 6x with two badly tapped 1/4" NPT holes in the main part of the chamber. .One was a mistake hole which had a plug in it and the other had my spark plug in it. Neither hole ever had any problems, which was pretty surprising to me. If I ever had to it again I'd figure out some kind of 1/4" NPT nut to put on the inside of the fitting to help ensure it wouldn't get shot out.

[Juggernaut12121]

Thanks, I'll probably just place it in a fitting.
Another question I found, in dealing with piston bounce, I thought of having a piece of pipe or something attached to the back of the where the spool unseats, the pipe would have a rut cut into it for a bolt that's perpendicular and attached to the spool. Once the spool retracts far enough back the bolt (which will be connected by a spring to another bolt) will snap into a second section of the same pipe where the groove widens, this will catch the bolt and keep the piston held back until it's pushed back into place. Any thoughts?

[MrCrowley]

Nifty idea, would like to see you give it a go. As long as the mechanism is strong, I think it would work.

[Juggernaut12121]

Would aluminum be alright? I've got it all on paper and the housing itself would be about 3/16'' thick, also, I'll need a machined piece to go on the back of the piston housing for the housing to thread onto (also made out of aluminum, the thinnest wall being the part threading onto the 2'' housing at 3/16'' as well). Would there be any problem trying it this way?
I cannot find that gasket type thing often used for the backstop as well.
Additionally, what would be a good ignition? I've got all the parts ordered and I was going to implement a tee halfway in the chamber to pop a spark plug in but I found a way I that I think might be better, it calls for the leads to be fed in from a tee on the crossbar but one side of the of the chamber will be about 8 inches longer than the piston side so I'm not sure how much that will effect performance.

Even newer update: Screw the locking mechanism, it just added complexity and expense, and allowing the piston to go forward any amount (I designed it to close a half inch) would kinda crap on performance. I figure I'll focus on making a more effective pilot exhaust. Additionally, where's a good place to learn/read up on fueling with oxygen and fuel? I heard it gave a more impressive report and kind of wanted to experiment with it.