| Author |
Message
|
| hubb017 |
 Posted: 03/26/2008 20:40 PM Post subject: The Hubbrid |
 |
|
Sarcasmo
Joined: 28 May 2007
Posts: 1439
513.36 Spud Bux
|
Like the name?
This is my first hybrid launcher, thanks to this site. It's nothing fancy, but it is my first and I am proud of it.
I've not taken past 6x, due mainly because I only have a bike pump. I just got an air compressor, so we'll see where that leads.
It is made of 2" Sch40 galvanized pipe. The meter is comprised of 1/4" nipples and 1/4" ball valves. The frame is made of two 2x4s nailed together. This keeps it off the ground. I plan on building a tripod for it one day.
Here are the pics:
| Description: |
| This is it. It is secured to two 2x4s with hose clamps. |
|
| Filesize: |
128.11 KB |
| Viewed: |
31 Time(s) |
|
| Description: |
| This is the meter. Note the pop-off. It is there to regulate the propane, in case I add too much. It is there, also, in case the burst disk does not rupture so I can release the buildup without taking the union apart. |
|
| Filesize: |
94.26 KB |
| Viewed: |
29 Time(s) |
|
| Description: |
| My propane tank holder, mounted to the frame with connected hose clamps. It is made from 3" Sch40. |
|
| Filesize: |
90.22 KB |
| Viewed: |
28 Time(s) |
|
| Description: |
| My homemade spark plug, made from a coat hanger, and 1/2" galv pipe fittings. |
|
| Filesize: |
68.13 KB |
| Viewed: |
28 Time(s) |
|
| Description: |
| Nothing fancy. I JB Welded the wires to the electrodes and super glued a piece of pipe over them. |
|
| Filesize: |
89.74 KB |
| Viewed: |
31 Time(s) |
|
| Description: |
| These are the burst disks and rubber washer I use to make the seal. The disks are grinded down Gatorade tops and the rubber came from a radiator cap. |
|
| Filesize: |
70.03 KB |
| Viewed: |
28 Time(s) |
|
|
|
| Back to top |
|
 |
|
|
|
| bigbob12345 |
| Posted: 03/26/2008 20:47 PM Post subject: |
|
|
Experienced n00b
Joined: 01 Dec 2007
Posts: 1516
370.57 Spud Bux
|
Very nice job
there have been a lot of hybrids lately
and is that a 1in or 3/4in union?
eighther way I reccommend you switch it out with a 1.5in union to exploit the power potential of a larger bore barrel.
|
|
| Back to top |
|
|
| Maniac |
| Posted: 03/26/2008 20:50 PM Post subject: |
|
|
Lieutenant Colonel
Joined: 23 Oct 2007
Posts: 475
533.09 Spud Bux
|
| Great i cant wait to see it in action. Im sure it will be devastating. any chance of a vid. Also great name
|
|
| Back to top |
|
|
| markfh11q |
| Posted: 03/26/2008 21:02 PM Post subject: |
|
|
Donating Member
Joined: 06 May 2006
Posts: 1383
1463.71 Spud Bux
|
Very noice! (At the risk of sounding like pimpmann22)
Do you use the fill-from-meter method of air injection?
|
|
| Back to top |
|
|
| hubb017 |
| Posted: 03/26/2008 21:32 PM Post subject: |
|
|
Sarcasmo
Joined: 28 May 2007
Posts: 1439
513.36 Spud Bux
|
bigbob: I don't really have a desire to increase the union size (I just wanted my feet wet with a hybrid, plus, it ain't coming off anyway).
Maniac: I don't know about a video. Maybe.
Mark: In the meter pic, the schrader is on the left side, although it may be difficult to see. The schrader has seen better days.
The union is a 1". I already had a 1" x 30" barrel and I built the launcher around it (although some would argue with that). It has a ratio of about .8 to 1.
|
|
| Back to top |
|
|
| LikimysCrotchus5 |
| Posted: 03/26/2008 21:41 PM Post subject: |
|
|
Brigadier General
Joined: 04 Sep 2007
Posts: 974
2284.20 Spud Bux
|
I like the spark plug and i think its what im going to use on my hybrid (eventually  ) but also what is the insulation on the wires? Is that electrical tape? And if not, then would electrical tape be a good insulator?
But overall, its nice and i like it. How about ammo?
|
|
| Back to top |
|
|
| hubb017 |
| Posted: 03/26/2008 22:28 PM Post subject: |
|
|
Sarcasmo
Joined: 28 May 2007
Posts: 1439
513.36 Spud Bux
|
The insulation is heat shrink tubing. I drilled two holes in the cap just slightly bigger than the coat hangers. I measured them, sharpened on end and looped the other, then put the tubing over the hangers and shrank it. I double layered it to make sure it would not ground out against the chamber. To secure them, I filled the pipe cap with JB Weld, then tightened down the nipple.
I guess electrical tape could work.
Ammo? Whatever fits in the barrel. It's a 1" barrel, and it holds dirt, pecans, rocks, and whatever else. Nothing permanent yet. I haven't shot a potato out of the hybrid yet, but this barrel has seen some starch movement.
|
|
| Back to top |
|
|
| SpudFarm |
| Posted: 03/27/2008 12:31 PM Post subject: |
|
|
Hybrid Guy
Joined: 04 Nov 2006
Posts: 1991
961.85 Spud Bux
|
get a marble barrel..
i like it! what does evbec say?
|
|
| Back to top |
|
|
| sniperjosh |
| Posted: 03/27/2008 14:18 PM Post subject: |
|
|
Specialist
Joined: 11 Oct 2005
Posts: 58
181.49 Spud Bux
|
Nice hybrid, Definitely get a marble barrel 
|
|
| Back to top |
|
|
| hubb017 |
| Posted: 03/27/2008 16:50 PM Post subject: |
|
|
Sarcasmo
Joined: 28 May 2007
Posts: 1439
513.36 Spud Bux
|
A marble barrel sounds like a good idea. I like to break $#!+.
As far as EVBEC, I've never taken the time to learn the program so I wouldn't know. I get familiar with it and see what it says.
|
|
| Back to top |
|
|
| SpudBlaster15 |
| Posted: 03/27/2008 17:25 PM Post subject: |
|
|
Human blast shield
Joined: 18 Oct 2006
Posts: 1539
11.03 Spud Bux
|
 When I saw this thread in the recent topics list, I figured it was some moron who was asking a question about a hybrid launcher, but completely mutilated the spelling of the word due to stupidity.
Anyway, nice looking hybrid, but the pop off valve really isn't necessary, as the schrader valve can be used to bleed the chamber pressure after a misfire, and the extra fittings add additional meter volume, which will create a smaller error margin for the meter pressure.
Also, in my experience, EVBEC has proven to be notoriously inaccurate when dealing with burst disks that rupture near the peak chamber pressure. From my limited use of the program, it seems that when attempting to use hybrid parameters in the program, BLB has it programed to model such scenarios by simply multiplying the energy of the given chamber at atmospheric pressure by the corresponding mix value, and as such the pressure curve will scale linearly. The problem with this lies in the fact that the test data he used to create the program (Latke's 3/4" barrel data) assumes that the static friction of the projectile is about 5 psig, and so assumes that the projectile will begin to move long before maximum chamber pressure is reached. While this probably won't be a problem when modeling hybrids with perfect C:B ratios (based on maximum efficiency between potential energy in the chamber, and work done on the projectile), hybrids with less than ideal ratios (Which encompasses every hybrid I have seen on this forum) will likely be firing projectiles much faster than what EVBEC predicts if an ideal burst disk is used.
A more effective method for these circumstances would be to use GGDT. Input your theoretical maximum chamber pressure, use a gas temperature of about 1/2 of the theoretical maximum temperature of a propane/air flame to account for heat loss and expansive cooling, and go from there.
|
|
| Back to top |
|
|
| hubb017 |
| Posted: 03/27/2008 17:31 PM Post subject: |
|
|
Sarcasmo
Joined: 28 May 2007
Posts: 1439
513.36 Spud Bux
|
The biggest reason I put the pop off on the meter was because it was the only "plug" I had to put in the tee, which I already had. Make sense?
In other words, this is basically a spare parts gun and it costs me about $10 to build and get working. Almost every piece on here was used on another launcher.
And, Spudblaster, I told you it looked like yours.
As far as the name, it's original. I can't remember how I came up with it...
|
|
| Back to top |
|
|
| SpudFarm |
| Posted: 03/28/2008 5:36 AM Post subject: |
|
|
Hybrid Guy
Joined: 04 Nov 2006
Posts: 1991
961.85 Spud Bux
|
i will love if/when you come back with upgrades
like a damage video/pics and some other interesting stuff..
of some reason this is one of the nicest hybrids i have seen (other than the monsters like jaush and FEAR etc)
job REALLY well done. do you got a chrony?
|
|
| Back to top |
|
|
|
|
