The Hater Cannon :: My First Spud Gun

Boom! The classic potato gun harnesses the combustion of flammable vapor. Show us your combustion spud gun and discuss fuels, ratios, safety, ignition systems, tools, and more.
User avatar
th3p0p0
Specialist
Specialist
Posts: 194
Joined: Tue Oct 31, 2006 12:34 pm

Thu Aug 13, 2009 1:44 pm

Are you using a burst disc??? with just a tater, how are you not launching with 55psi of MAPP??
55 in the meter not the gun it self. do you know how a combustion works?

not trying to be a ass just saying.
User avatar
Ragnarok
Captain
Captain
Posts: 5401
Joined: Tue Dec 19, 2006 8:23 am
Location: The UK

Thu Aug 13, 2009 1:50 pm

Chalk up another person who's not believing those ranges.

I don't know whether you've mis-measured, or aren't being truthful with us, but potatoes aren't even close to being ballistically efficient enough to be launched those distances at any velocity within that cannon's limits.

It's a nice cannon, but it's not a half mile cannon. I could believe a quarter mile from the right cannons, but I'd still raise an eyebrow at that number from this one.
Does that thing kinda look like a big cat to you?
User avatar
jackssmirkingrevenge
Five Star General
Five Star General
Posts: 26203
Joined: Thu Mar 15, 2007 11:28 pm
Has thanked: 569 times
Been thanked: 344 times

Donating Members

Thu Aug 13, 2009 1:52 pm

You could always put a frozen spud over a chrony and let the range boffins here crunch the numbers ;)
User avatar
th3p0p0
Specialist
Specialist
Posts: 194
Joined: Tue Oct 31, 2006 12:34 pm

Thu Aug 13, 2009 1:58 pm

I don't know whether you've mis-measured, or aren't being truthful with us, but potatoes aren't even close to being ballistically efficient enough to be launched those distances at any velocity within that cannon's limits.


well i was there when the "half mile shot" was taken it we saw the potato hit the embankment on the other side of the river sooo were not bullshitting you and as far as measuring programs we used google earth no ggdt or any of that.
User avatar
jackssmirkingrevenge
Five Star General
Five Star General
Posts: 26203
Joined: Thu Mar 15, 2007 11:28 pm
Has thanked: 569 times
Been thanked: 344 times

Donating Members

Thu Aug 13, 2009 2:14 pm

By way of comparison, the M79 grenade launcherfires a rifled 40mm grenade - with presumably a better ballistic coefficient than a potato that's less dense and tumbling in flight - but at a relatively low velocity of around 250 feet per second, and can "only" manage 440 yards, that's 1/4 of a mile and half the distance you're claiming.

Your shots are doubtless leaving the muzzle faster than with but when it comes to range, aerodynamic drag and sectional density is a big factor and using a potato as a projectile is well... using a potato as a projectile ;)
User avatar
MrCrowley
Moderator
Moderator
Posts: 10078
Joined: Fri Jun 23, 2006 10:42 pm
Location: Auckland, New Zealand
Been thanked: 3 times

Thu Aug 13, 2009 2:31 pm

th3p0p0 wrote:
I don't know whether you've mis-measured, or aren't being truthful with us, but potatoes aren't even close to being ballistically efficient enough to be launched those distances at any velocity within that cannon's limits.


well i was there when the "half mile shot" was taken it we saw the potato hit the embankment on the other side of the river sooo were not bullshitting you and as far as measuring programs we used google earth no ggdt or any of that.
Can you give us the coordinates of this river in Google Earth? Just for the sake of it.

Wait a tick, how can you even see it hit the other side? I can't even see a golfball land 450 yards away. And it's not like a potato stands out more than a golf ball would (in the air a potato probably would though).
jeepkahn
Corporal 3
Corporal 3
Posts: 747
Joined: Fri Jan 09, 2009 1:11 pm
Location: Triad, NC, USA

Thu Aug 13, 2009 2:32 pm

th3p0p0 wrote:
Are you using a burst disc??? with just a tater, how are you not launching with 55psi of MAPP??
55 in the meter not the gun it self. do you know how a combustion works?

not trying to be a ass just saying.
The way it was listed in the specs made it sound as though your were pressurizing to 55psi in the chamber, otherwise it's a pointless referance.

Yes, I know how a combustion works... Do you know how small a 1.5" tater is at 800yds???(saw it land)edit:Mr.C beat me to the post putton.

We're not trying to bust bubbles on the performance, just questioning the accuracy of your measurments...

and if there was a 25mph tailwind above 300ft elevation then a tater can carry an extra coupla hundred yards.... I know from shooting glowmissiles straight up they'll be directly overhead at apogee, but will fall about 200yds downwind, but that is also from a confirmed 1/2mile capable cannon...

You really need to lighten up, not many get the compliments on a first build that this one did...
My Cannons can be found by clicking the following link.
http://www.spudfiles.com/forums/viewtop ... tml#256896
User avatar
Ragnarok
Captain
Captain
Posts: 5401
Joined: Tue Dec 19, 2006 8:23 am
Location: The UK

Thu Aug 13, 2009 3:42 pm

th3p0p0 wrote:Well I was there when the "half mile shot" was taken it we saw the potato hit the embankment on the other side of the river.
I always immediately doubt anyone who says they can see anything that small at those distances - and determine how far away they thought it was.
MrCrowley wrote:Wait a tick, how can you even see it hit the other side?
You could claim that you didn't see a splash from it hitting the water, but I wouldn't take that as any kind of proof.
Does that thing kinda look like a big cat to you?
User avatar
adrak
Private
Private
Posts: 10
Joined: Wed Aug 12, 2009 10:44 pm

Thu Aug 13, 2009 3:59 pm

Ragnarok wrote:You could claim that you didn't see a splash from it hitting the water, but I wouldn't take that as any kind of proof.
The shot didn't land in the water, it landed in the tree cover which we saw take the hit. The local avian are incapable of expelling 1.5" x 3" solid feces and there was nothing on the other side for us to mistake for the potato. Even if they were I'm sure we would notice a goose take a sudden vertical climb from the force of the poo and I'm sure we'd hear it's report of anger, suffering, and relief.
Last edited by adrak on Thu Aug 13, 2009 4:00 pm, edited 1 time in total.
User avatar
th3p0p0
Specialist
Specialist
Posts: 194
Joined: Tue Oct 31, 2006 12:34 pm

Thu Aug 13, 2009 3:59 pm

well in all truthfulness idc what you guys say we saw it it happened whether you believe us could not matter less to me. lighten up? i said i wasn't trying to be a ass. once again i am am not trying to offend any one.
User avatar
jackssmirkingrevenge
Five Star General
Five Star General
Posts: 26203
Joined: Thu Mar 15, 2007 11:28 pm
Has thanked: 569 times
Been thanked: 344 times

Donating Members

Thu Aug 13, 2009 4:20 pm

th3p0p0 wrote:Once again I am not trying to offend any one.
No one's trying to offend you or the OP either, no one is claiming that you are deliberately exagerating the range - but as with anything else (fishing, religions etc.) extraordinary claims require extraordinary proof.

I would accept the claim if you actually found the projectile where it landed then measured the distance from the launcher, but otherwise it's only natural to be met with scepticism, particularly from those who have built similar launchers.
User avatar
Ragnarok
Captain
Captain
Posts: 5401
Joined: Tue Dec 19, 2006 8:23 am
Location: The UK

Thu Aug 13, 2009 4:54 pm

@adrak: Amazing! Your sarcastic response has done absolutely nothing to change my evaluation of the situation!

You've provided nothing but your unprovable assertions you've genuinely achieved a range that is in excess of double what similar cannons are capable of - nor have you made mention of conditions that might make it more feasible, such as a strong tail wind.
jackssmirkingrevenge wrote:I would accept the claim if you actually found the projectile where it landed then measured the distance from the launcher.
Not really. They can't exactly provide proof that they did actually find the projectile there, then make an accurate measurement.
Even on video, there's nothing to stop dodgy measurement nor "planted" projectiles.

With reasonable evidence of velocity and projectile mass/dimensions, it's possible to do trajectory modelling, but I can't see that the end result will get close to the claimed one.
Does that thing kinda look like a big cat to you?
User avatar
Hotwired
First Sergeant 3
First Sergeant 3
Posts: 2599
Joined: Fri Oct 13, 2006 5:51 am
Location: UK

Thu Aug 13, 2009 5:03 pm

~450m is about where my launcher (theoretically) caps out and at that range, you'd need to be a hawk to see a 1/2" dart come down. Which is one reason why I don't bother with it much, never seen any of them again, coming down at a fair few knots they just dive into the ground... and become invisible.

Some fiddling with GGDT would suggest that for a 300g 1.5" mass screaming out of a 5'/~153cm barrel, to get 800m it would have to be banging along at about 140m/s with about 3000J of muzzle energy.

Might be being a bit generous on the weight there but if it was 200g of mass it would be 190m/s and 3600J of muzzle energy.

Quite high pressure was required.

Any claim of a half mile shot from a handheld cannon will get funny looks simply because it doesn't tend to happen. If you make the claim and the reply is "yeah right", just leaving it at that undermines your credibility and it won't be accepted.

I'm not taking a side, I'm just scribbling some thoughts.

On a lighter note it's a dam good first try cannon ^_^
User avatar
jackssmirkingrevenge
Five Star General
Five Star General
Posts: 26203
Joined: Thu Mar 15, 2007 11:28 pm
Has thanked: 569 times
Been thanked: 344 times

Donating Members

Thu Aug 13, 2009 5:10 pm

Ragnarok wrote:They can't exactly provide proof that they did actually find the projectile there, then make an accurate measurement.
Even on video, there's nothing to stop dodgy measurement nor "planted" projectiles.
I'm not saying it's not falsifiable, but I'm assuming in this case that those putting forward the claim are under a misapprehension and not actively trying to demonstrate false results.
User avatar
Hubb
First Sergeant 2
First Sergeant 2
Posts: 2390
Joined: Mon May 28, 2007 8:39 am
Location: South Georgia
Contact:

Thu Aug 13, 2009 5:31 pm

Reading through this topic explains why it is called the Hater Cannon.....

With that said, I'm neither going to confirm nor deny my belief in the distance claim. I will say, as do most everyone else in this topic, that this is a very well put together launcher. Oh, and welcome to Spudfiles.
Post Reply