P2 combi spear

[Otto]

Hi,
I'm new here but have been checking the site for a couple of years. I have finally taken the plunge to start putting together a costume after buying some parts earlier this year. I now have almost everything for a P2 costume with the exception of the P2 upper armor. Now I have to start the latex painting.

Like many I would love a working P2 spear, as close to screen accurate as possible. I know this subject has been covered several times here already. I have spent quite a bit of time researching how this can be achieved. It is all theory so far, I admit the proof will be in actually building it. I think I am on the right track though as I recently read the thread of the person who has a functional spear (their own design) with the video on youtube (sorry I dont recall his name). The mechanism I had figured out is basically the same as what they have used. It comprises of one dc motor, a worm gear box (right angle) which pulls fishing line to move the spears (copper 3/8 pipe). I will weld the copper tube to be three-part telescopic. Additional smaller tubes will be attached to feed the fishing line between the 3/8 copper tubes to allow them to move smoothly. Basically the spears will extend 30" on either side and will fully retract. Total length extended 84" (the actual prop was 95" but considering I am only 6ft, the 1ft shorter length will look relatively proportional). The motor will allow these to be moved between 20-30" per second. Slower than the speed it extends in the movie but similar to the speed it is shown retracting. Once I have some videos of progress I will share them.

The starting point is getting the main spear body. Two weeks ago a set of two icon casts sold on Ebay which I wish I had seen beforehand. I am going to post a wanted ad in marketplace for a P2 spear.

 

[Otto]

Hi,
I haven't posted in a couple of months but have spent hundreds of hours so far working on this project. Since my previous post I have purchased many of the parts needed. It wasn't easy as I currently live in a small country (Guyana) where none of the parts needed are available. For example, copper pipe of any size is not sold in the country. So I had to ship the parts to my US address and bring them here in my luggage. So far I have purchased the following:-

About 10x brushed DC motors, different sizes, RPM's & torque ratings. I am still considering brushed motors using diodes for the stop function (similar to how car antennas stop) but due to space constraints I am limited to using a very small motor. I am now testing radio control car motors that have higher torque. I will also be testing brushless outrunner motors using an electronic speed controller. These have a lower RPM and will not require reduction gears. Both set-ups will also incorporate a slipper clutch to prevent damage when the spear stops.
3x 90 degree gear motors. I will not be using these as the gear pitch is too small and the gears will shred due to the sudden stop action of the spear. 4x Lithium 9v batteries. These are now dead due to discharging too fast with the larger motors. I will now be using small, high discharge Lipo batteries used for RC models.
40' Copper pipe 1/2 OD, M class.
2' 2-3/8"mm OD stainless steel tube 22 gauge thickness. This is for the outside of the copper tubes. This size is difficult to find and costs about $60. I think 18 gauge would work and is half the price but will be heavier.
6' 1/8" copper bendable pipe (for fishing line to run through).
1 Master Replicas spear.

I could quite easily solve motor mechanism quickly using bigger components, however I am aiming to keep the motor mechanism as small as possible (2" to 2 1/2" long) so that the spear extends as long as possible (bigger motor and gears means less space for copper tubing). This is taking time to perfect.

Once assembled the unit will be contained and fully functional within the stainless steel pipe. The master replicas spear will drilled hollow at either end using a 2 3/8" hole saw and the stainless steel unit will slide in. To clarify, the master replicas spear will not need to be cut in half.

I will post a further update with photos in a couple of months.
Otto