Darth Freyr's Content

#264799 Puget Sound Nerf War

Posted by Darth Freyr on 09 February 2010 - 12:35 PM in Nerf Wars

I will probably be there. Is anyone willing give me a ride to the war, preferably from the Eastside? I would help pay for gas, ferry etc. I will probably need to borrow some of the community darts. Tantum, could you please bring two RF20 spacer plates for pickup. Thank you. If anyone wants to buy a +bow and save on shipping, the price is negotiable.

#259270 Nice Airgun Trigger Design

Posted by Darth Freyr on 17 December 2009 - 07:53 PM in Homemades

Having built one of these, I have a few pointers. A good combination for those of us not in Europe is 1/8" brass tubing and a brass 3/16" barb to 1/8" MPT, at least those from my ACE. I found that the bulk fittings were better than the ones in the small plastic containers. I believe I also used a #4 flat head sheet metal screw. When I say flat head, I mean the actual screw head type, not the driver shape.

#255029 Sano Halloween

Posted by Darth Freyr on 31 October 2009 - 09:27 PM in Nerf Wars

Don't let the rain stop anyone from coming. We can still nerf even if Disturbed isn't there. I don't think the war should be cancelled; I'll nerf with whoever shows up, regardless of the rain.

#254427 Heeelllp! Ignore-problem Solved

Posted by Darth Freyr on 24 October 2009 - 11:06 AM in Modifications

Check the seal everywhere between the plunger tuba and the turret. Make sure nothing is restricting airflow. You could also try rebarreling the turret.

#253982 Barrel Spacer Plate Dimensions

Posted by Darth Freyr on 19 October 2009 - 06:53 PM in General Nerf

Just Some Bob got 0.90" for the LB, and I believe his process was correct. The Berserker has an axis-barrel center measurement of 2.171875" or 139/64".

#253927 Barrel Spacer Plate Dimensions

Posted by Darth Freyr on 19 October 2009 - 09:29 AM in General Nerf

I did a bit of math. I got about 1.376*x. To verify, your measurement is around 0.654. For all interested, the coefficient is the cotangent of 36, or tan(36)^-1, not to be confused with tan^-1(36), the inverse tangent.
Ignore the above failure. My original calculation lacked both correctness and common sense. Don't do math when tired. The actual diameter is 0.851*x or x/(2*sin(36)). This is what Just Some Bob originally said he did and what he said he was using regardless of the math.

#253213 Puget Sound Nerf War

Posted by Darth Freyr on 10 October 2009 - 11:21 PM in Nerf Wars

I am posting to confirm that I will be there. I will have 2 +bows for sale for $110.

#252448 Regarding Barrel Replacements

Posted by Darth Freyr on 03 October 2009 - 09:23 AM in General Nerf

I see a few problems with your concept. First of all, vacuums don't "pull", but the accompanying high pressure pushes. Furthermore, your estimation of barrel length does not take into account friction or the possibly insignificant momentum of air. Not including friction leads to barrels that are entirely to long. Burning a hole in the back of a stefan would most likely increase the dart-barrel seal. Some people have actually had a increase in their real ranges using stefans with holes. Also, breaches can be very effective in placing stefans very close to the air source, also called reducing "dead space". Instead of making estimations with physics concepts, try making some actual calculations, using fluid dynamics modeling software, or getting some barrel material (you can use empty Crayola or Rose-Art marker cases) and doing a mod instead taking the time to write a huge post.

Beaten to it, thought I'd post anyway. Would an "anti-bow" be bending over backward?

#252174 Sano Halloween

Posted by Darth Freyr on 30 September 2009 - 08:58 AM in Nerf Wars

I will probably be there, but I am not sure yet.

#251779 Homemades Picture Thread

Posted by Darth Freyr on 26 September 2009 - 09:50 PM in Homemades

My Snap:

Normal Snap internals and a +bow spring. Close up on some parts.
The handle is hose clamped on. The trigger is "pulled" by pushing your finger upward.
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The stock is made of 3/4" PVC with pipe insulation padding.
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The priming handle is made of CPVC fittings and is attached with a 4-40 screw for removability.
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The triple RSCB rotates on a 1/4" rod. When the first tube is empty you pull it back, turn it 120 degrees, and let it go. The tee has some o-rings so the RSCB is sealed but still easy to pull out. Also, unseen in the tee is a piece of 5/8"*3/4" vinyl tubing to guide the darts into a 12" CPVC barrel with a hole in the bottom to allow air flow.
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Also, the breech to my +bow.
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It is a spring operated CS-style breech. The handle is screwed into the 1/2" CPVC and superglued on. At the rear of the assembly is a piece of 21/32" brass, which makes an airtight seal with the CPVC.
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#251361 Puget Sound Nerf War

Posted by Darth Freyr on 22 September 2009 - 10:11 PM in Nerf Wars

I will probably be there if I can get a ride. I live in the Rose Hill area of Kirkland.

#250745 W@c The Revival!

Posted by Darth Freyr on 17 September 2009 - 11:35 PM in Nerf Wars

I've just gotten everything figured out. I'm 90% sure I will be there.

#250726 Ss2 Leakage Problem

Posted by Darth Freyr on 17 September 2009 - 07:21 PM in Modifications

Check if there is something keeping the valve from fully closing. There may be something like a small piece of adhesive on the front of the sealing surface.

#249307 How Do Semi-auto Air Blasters Work?

Posted by Darth Freyr on 01 September 2009 - 11:12 AM in General Nerf

Hornet tanks and some others actually fire when the pressure in the tubes behind them is released, which is what the piston and blast button do. The piston like device functions like a blast button. As you pull the trigger, the head of the piston moves back, which causes one tank to release pressure to the atmosphere like a blast button would, which fires the tank. The blast buttons are connected to all the tanks, so when they are pressed all the tanks fire

#247581 Foam Backing Rod

Posted by Darth Freyr on 18 August 2009 - 11:19 PM in General Nerf

Are your darts too short for the breaching mechanism? I measured my foam to have a diameter of 12.5 millimeters, however it's relatively thin. Did you measure your foam as 13 millimeters or is that just what the package says? If not, the actual diameter may be much greater.

#246510 2k Pump Tube Replacement?

Posted by Darth Freyr on 10 August 2009 - 11:06 PM in Modifications

21/32" brass has an I.D. of 5/8", so if cpvc fits perfectly in at2k pump tubes that should work. You don't really need something with the exact same I.D. though; you could just get a different o-ring that fits your pump tube.

#246442 Berserker Internals

Posted by Darth Freyr on 10 August 2009 - 03:25 PM in General Nerf

Mine does real slam fire. It releases the catch when the handle is at the end of its forward stroke. However, slam fire only works consistently when I go slowly, it doesn't fire when I pump too quickly.

#246214 Inline Airtank

Posted by Darth Freyr on 08 August 2009 - 11:05 PM in Homemades

To reduce the large amount of dead space inside the large airtank, I think you should relocate the hose handle to the front of the tank.

#241372 Industrial Velcro

Posted by Darth Freyr on 10 July 2009 - 09:44 PM in Modifications

I don't see how velcro wouldn't work. If you used something like McMaster #95005k811 and had about 4 sq. inches, the shear strength would be about 58 lbs., much greater than the applied force, and the peel strength would be about 3.6 lbs., easy enough to remove. The cycle life on that velcro is 3500, which means you could remove and reattach the Gemini 3500 times before you got to half strength. Furthermore, to attach the velcro to the blaster, you could drill small (~1/16") holes in the shells of both blasters and feed thin wire through the holes and the velcro backing.

#235027 Finished Physics Project

Posted by Darth Freyr on 08 June 2009 - 06:08 PM in Off Topic

Star Wars blasters are not lasers. From Wookiepedia:

Blasters were a considerable improvement over the archaic laser design. Instead of a coherent beam of light and heat like a simple laser, the blaster fired a highly compressed, focused high-energy particle beam that was very deadly to most creatures. The energy that made up the blaster bolt depended on the type of blaster being used.

Whether or not lightsabers deflect lasers is a moot point. in response to your "circular blade" statement, how about a very long, thin ellipse, with the majority of the length outside the handle and a small section inside. Reacting at the speed of light is unneeded as the projectiles are flying at a fairly low speed, which you would have noticed if you actually watched the movie.

#234261 Recon Straw Breech Mod

Posted by Darth Freyr on 04 June 2009 - 12:31 PM in Modifications

It is the volume of the entire barrel. You're looking for the length of the barrel. The main section gives you the pressure in atmospheres. Convert this to a force / area pressure scale, e.g. pounds / sq. inch. Multiply this by the cross-sectional area of your barrel, probably around 0.2 sq. inches. This resulting number is the force acting on the dart at the end of your barrel. You can find the friction by putting the dart in the barrel, placing a short spacer in front, and pushing the barrel into an accurate scale.

Friction = ((1.7 + 0.3 + 0) / (0.3 + 0 + 0.2 * barrel_length)) * 14.6 * 0.2

Find your friction, plug it in, and solve some equations (or just let me do it).

#234240 Recon Straw Breech Mod

Posted by Darth Freyr on 04 June 2009 - 08:44 AM in Modifications

I stated the dead space and straw as two things because I thought it would be simpler that way, and I thought you may have some dead space in the barrel. Plunger_volume is the used volume of the outside part. Straw_volume is obvious. Dead_space is unused space behind the dart. Barrel_volume_behind_dart is the volume of the barrel the dart has already passed through, the length of which you are looking for. Use this big equation to find the pressure in the blaster, multiply by the area behind the dart, and you have the force behind the dart. When this force equals your friction, that is your barrel length. This approach uses only static pressure, not dynamic pressure, so you may find that the prediction is slightly lower.

#234209 Recon Straw Breech Mod

Posted by Darth Freyr on 03 June 2009 - 11:02 PM in Modifications

A 5" barrel may use all the air, but that air will not have enough force to continue to push the dart at the end. Try redoing the equations so the barrel ends when the force behind the dart is equal to the force of friction on the dart. The pressure behind the dart, in atmospheres, would be (plunger_volume + straw_volume + dead_space) / (straw_volume + dead_space + barrel_volume_behind_dart). The force would be pressure, in your preferred unit, times the cross-sectional area of your barrel. Friction can be found by placing the dart in your barrel, placing a short spacer in front, and pushing the assembly into an accurate scale. Use the highest reading as your friction. This approach, modified to fit your blaster, will work for optimum barrel length in any blaster.

#233713 +bow: Diy Thread

Posted by Darth Freyr on 31 May 2009 - 11:26 PM in Homemades

Lt. Stefan: I believe I have the same model as you and the manual specifically states to turn the lever one full rotation clockwise, especially if the blade is loose.

#231660 Nerf Nade

Posted by Darth Freyr on 21 May 2009 - 08:28 AM in Homemades

The only way you can use a spring powered launcher is with a quarter inch barrel or if you use a SNAP or a Big SNAP. To shorten the length you could use multiple plunger assemblies. You could also use a SNAP design without the plunger head to just push your grenade.

#231438 The Rogue "sereph"

Posted by Darth Freyr on 19 May 2009 - 11:11 PM in Modifications

A compromise for linked triggers would be to have the trigger linked to a keyring, small carabiner, etc., and connect that to the attachment's trigger. This would allow you to retain the modularity and have linked triggers.

#227397 Strange Bbb Occurrence...

Posted by Darth Freyr on 30 April 2009 - 10:24 PM in General Nerf

That wouldn't explain the fact that it just wasn't priming. No parts were damaged at all, and were hardly used beforehand.

Is the shell not staying back or is the plunger rod catch not re-engaging when you push it forward? If it's the shell, check the catch for the shell (it's the little orange pin that sticks out near the back of the front half) for wear and springs and check the catch face on the shell for wear. If it's the plunger rod catch, just replace the spring with one from a clicky pen.

#224656 Assistance Requested

Posted by Darth Freyr on 20 April 2009 - 10:05 PM in Modifications

Your rotation mech. is probably worn down. A nearly pristine mech. looks like this.
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You could take Draconis' offer or repair your using epoxy putty.

#223574 Compact Homemade

Posted by Darth Freyr on 14 April 2009 - 02:00 PM in Homemades

How about something like this.
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Instead of using a back-pressure system, just use a traditional tank and valve. I believe someone made a homemade tank, you could just us a longer pin. Pump back and forth to prime and pull all the way forward to fire.

#223390 Compact Homemade

Posted by Darth Freyr on 13 April 2009 - 02:20 PM in Homemades

I think it would work and I never said or "impiled" anything to the contrary.

#223387 Compact Homemade

Posted by Darth Freyr on 13 April 2009 - 02:04 PM in Homemades

It could be thought of as a check valve with a manual release.

#223366 Compact Homemade

Posted by Darth Freyr on 13 April 2009 - 09:11 AM in Homemades

My argument still holds. Tank pressure + cracking pressure = pressure in the pump. Can you see the pump, when fully compressed, has a greater pressure than the tank. The blast button has nowhere to release. Air would most likely flow in the opposite direction. Tantum's idea would work, but I don't believe it needs the gizmo on the bottom.

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