Easy to make "Internal" Grip Launcher

[Team DARTSKS]

I made a website about my other launcher a long time ago. Forgive the poor graphics, I'm not much of an artist. http://www.geocities.com/af_wr/. That's not my latest version, I now have one that's basically the same but with a copper pipe inside of the PVC pipe so it can handle higher pressures. It's quite a bit of work to make, but it can launch anything with a standard bottle neck and requires no release cord. You just take pressure off of the air line to launch.

SaskAlex, I tried to look up your other launcher on the Geocities website but it said it was closed. Any other way to see it? I wanted to compare it to one I am building. Thanks, Papa WRockit

[WRA2]

I made a website about my other launcher a long time ago. Forgive the poor graphics, I'm not much of an artist. http://www.geocities.com/af_wr/. That's not my latest version, I now have one that's basically the same but with a copper pipe inside of the PVC pipe so it can handle higher pressures. It's quite a bit of work to make, but it can launch anything with a standard bottle neck and requires no release cord. You just take pressure off of the air line to launch.

SaskAlex, I tried to look up your other launcher on the Geocities website but it said it was closed. Any other way to see it? I wanted to compare it to one I am building. Thanks, Papa WRockit

The link you provided gives the following error message.


Sorry, the GeoCities web site you were trying to reach is no longer available.

Please correct

[ninja_iga]

wow! this is truly revolutionary!

i think i just might make one!

[rockets-in-brighton]

I made a website about my other launcher a long time ago. Forgive the poor graphics, I'm not much of an artist. http://www.geocities.com/af_wr/. That's not my latest version, I now have one that's basically the same but with a copper pipe inside of the PVC pipe so it can handle higher pressures. It's quite a bit of work to make, but it can launch anything with a standard bottle neck and requires no release cord. You just take pressure off of the air line to launch.

SaskAlex, I tried to look up your other launcher on the Geocities website but it said it was closed. Any other way to see it? I wanted to compare it to one I am building. Thanks, Papa WRockit

The link you provided gives the following error message.

Sorry, the GeoCities web site you were trying to reach is no longer available.

Please correct

Geocities is closed. There is a partial archive (no images) here http://geocities.ws/af_wr/ that you could use for the moment.

[SaskAlex]

Sorry everyone. I'm pretty sure I still have all the pictures on my computer, so I'll try and hunt around for them and put them on here later tonight or tomorrow. Since it's a completely different launcher, I'll probably just start a new thread and call it "Another internal grip launcher" or something like that.

Alex

[SaskAlex]

Alright, here is the new thread:
http://www.wra2.org/forum/viewtopic.php?f=10&t=894

[tcarnahan]

Well, the reason I put "Internal" in quotation marks is that this isn't really an internal grip launcher. It's a no grip launcher. Nothing holds the bottle on the launch tube because there is nothing pushing it off. You have to use a spliced bottle, an FTC rocket, or something else that has an upper bulk head made from a bottle neck. The launcher seals on both the top and bottom bottle necks, so there is nothing pushing the rocket off as you pressurize. Check out the (quick) drawing below. Note that the main PVC pipe in the drawing is shown much shorter than it actually is. The rocket is placed over the launcher and the o-ring makes the seal with the upper bottle neck. Teflon tape must be used for the seal between the nozzle and the launcher, unless you wanted to put grooves for o-rings at a different spot for each rocket you use.

Pump air through the left schrader valve to pressurize the rocket, and then pump air through the right one to launch it. All this pressure has to overcome is the friction at the o-ring and teflon seals, and it only has to push the rocket up far enough that the top bottle neck no longer seals. From that point on, the internal pressure of the rocket will push it off the launcher like on any other launcher. With my pump and 25' air line this only takes two strokes.

This launcher certainly has some drawbacks- teflon seal instead of o-ring, can't launch a single bottle, etc., but it has some nice advantages. There is nothing gripping the nozzle, so you can put on any kind of fins or fairings that you want. Also, using a pump to launch instead of a pull string means you can't pull your launcher over.

This should also be very easy to make out of metal piping, which I plan on doing. So far, I've only had it up to about 100 psi since it's all PVC. One possible point of failure is the collapse of the 1/4" vinyl tubing under the external pressure in the launcher. I think it would take a lot of pressure to make that happen though. This is the stiffer white stuff, not the clear flexible tubing.

Let me know what you think,
Alex

This is a really cool concept. Maybe I am a little dense, but what seals the bottom of the rocket? I didn't think I saw a seal or o-ring there.

Also, the link you gave for the other diagrams ("geocities") no longer works. Could you post them at this site?

Thanks,

Tom

[WRA2]

Also, the link you gave for the other diagrams ("geocities") no longer works. Could you post them at this site?

Thanks,

Tom

You can view the text only from the original site at

http://geocities.ws/af_wr/

Too bad the images are lost

(this is the main reason we require attached images as opposed to the "img" tag)

You also can view the other pages of the site by copying the links from the page and inserting the .ws geocities.ws/******.

If anyone finds the images let me know so I can put them into attachments in this thread.

[U.S. Water Rockets1]

Didn't Geocities get bought out by another internet provider? Would it be possible that they could have relocated the sites to another domain?

[SaskAlex]

This is a really cool concept. Maybe I am a little dense, but what seals the bottom of the rocket? I didn't think I saw a seal or o-ring there.

Also, the link you gave for the other diagrams ("geocities") no longer works. Could you post them at this site?

Thanks,

Tom

Sorry everyone, haven't been around in a while. School and all that. I my thread for the other launcher a while ago. http://www.wra2.org/forum/viewtopic.php ... cher#p7179. I just forgot to update the link in this thread.

And no, there is no o-ring on the bottom. I've been using teflon tape wrapped around the launcher. If you do it right, it will hold considerable pressure. It's a bit of a pain, but it allows you to make a seal anywhere on the length of the launcher.

Alex

[WRA2]

Sorry everyone, haven't been around in a while. School and all that. I my thread for the other launcher a while ago. http://www.wra2.org/forum/viewtopic.php ... cher#p7179. I just forgot to update the link in this thread.

Alex

Welcome back Alex!

It has been a long winter for everyone in the northern hemisphere.

[Brian]

And no, there is no o-ring on the bottom. I've been using teflon tape wrapped around the launcher. If you do it right, it will hold considerable pressure. It's a bit of a pain, but it allows you to make a seal anywhere on the length of the launcher.

Alex

How do you get the teflon tape to stay on the launcher?

[Spaceman Spiff]

And no, there is no o-ring on the bottom. I've been using teflon tape wrapped around the launcher. If you do it right, it will hold considerable pressure. It's a bit of a pain, but it allows you to make a seal anywhere on the length of the launcher.

Alex

How do you get the teflon tape to stay on the launcher?

I don't know if this is the same thing or not but I use teflon tape to seal the threads of my fittings and if you pull it tight when you wrap it over something then the teflon conforms to the surface and it sticks to itself a bit forming a coating of teflon tape. It is fragile and will wear off if you mash on it, but I can see a setup where you apply the teflon to a launcher as a low friction seal and you replace it each time you load the rocket. Teflon tape is super cheap, so it would not be a big problem to replace it for every launch.

[SaskAlex]

Like Spaceman says, it's not that hard to make the teflon tape stay put when you wrap it around the launcher. It helps if you go upwards instead of downwards when you wrap- you want the outer layer of the wrap to be the highest.

And as it turns out, I already updated this thread about the outdated link- right above the recent post which asked about it, actually. I don't think I was able to edit my posts when I did that, so I couldn't remove the old link. I've now removed it from all of my previous posts, but I can't do anything about the endless posts that have quoted it.

[U.S. Water Rockets1]

Like Spaceman says, it's not that hard to make the teflon tape stay put when you wrap it around the launcher. It helps if you go upwards instead of downwards when you wrap- you want the outer layer of the wrap to be the highest.

And as it turns out, I already updated this thread about the outdated link- right above the recent post which asked about it, actually. I don't think I was able to edit my posts when I did that, so I couldn't remove the old link. I've now removed it from all of my previous posts, but I can't do anything about the endless posts that have quoted it.

The teflon tape will not make much difference in altitude if it is only on the tube to provide a seal, you can use electrical tape or a rubber sleeve. The ease which the rocket slips off the base of the launcher doesn't change the speed of the rocket in any measurable way.