Autonomous hybrid IV

[hectmarr]

This is the project that I am working on. It is the prototype 4, of the series of autonomous hybrids.
I plan to introduce improvements, in several aspects.
The dosing unit will be activated by the piston rod of the combustion chamber, just like in my semi-automatic hybrid. In this case, the solenoid valve 5/2, cleans the combustion chamber of burned gases and injects the combustible gas into the doser, at the same time, leaves everything ready to load the ammunition and pump the air.
The air pump will be of two stages, double acting and lever. It is finished, and it works very well. It is smooth to operate and in 5 cycles it will fill the combustion chamber to 9X.
The caliber is 6.35 mm, it shoots diabolos, I already bought the barrel with 12 micro striations, 24 "long.
The ammunition loading system will be the same as my HA -3, which has been tested quite a lot and works perfectly.
The high-pressure check valves, I have made them myself, are two, the mixing feed and the output of burned gases. The latter is operated by a small pneumatic actuator incorporated into the weapon.
The combustion chamber has a new spring, of better quality than the previous ones, to retain the mixture of air and butane. In theory it can hold up to 15X without uncovering the gas outlet orifice. The two high pressure valves, are located in the head of the weapon, where it has the ignition, which will be a piezo igniter of those used in domestic stoves and ovens, have worked very well all (I have 8).
I put here, some diagrams and some photos of what I'm building. Some images and diagrams have already been uploaded previously, but it seems better, so that everything is clearer, put everything together here.
This time, I will try to document the design and construction of the weapon, because I have always built tested and last, showed my works. I will update everything on the HA 4 right here.

[Anatine Duo]

I didn't want to admit this, but I am confused as to how this works. Excited... but confused. It's inspiring me to study it...

[hectmarr]

I didn't want to admit this, but I am confused as to how this works. Excited... but confused. It's inspiring me to study it...

Actually it is not complicated but when you see everything together you can confuse a little.
It is a hybrid weapon similar to a compressed air pellet gun, I mean in the form of a rifle, and it operates as a pumping weapon, (Benjamin 392, Daisy 880, and many others).
Basically you need a combustion chamber, a fuel gas doser, so that the butane-air mixture is stoichiometric, (in the optimal proportions to make it flammable), the air pump and the system for loading and firing ammunition. They are powerful weapons for weight and size, and for the low pressure that is necessary to fire.
If you have any questions, tell me and I'll clarify the subject.
This is a video of model 3, shooting.

[jackssmirkingrevenge]

Great work on the pump! I look forward to seeing it in action

[hectmarr]

Thanks Jack! I'm working on everything else, but someday I'll finish the job

[hectmarr]

I'm finishing the system to load the pellets. It is built with recycled materials. In the diagram you can see what the construction is like to support the shots. In black, what is metal, and in gray, what is fiberglass and resin.
In the photos, the surface finish of the fiberglass parts is missing. I add a small layer of resin with industrial talc, so that it is smooth, without pores. The dark color is because of the graphite that I used to test everything in a lubricated way. It is the least dirty because otherwise I have to apply grease and it is a scab, especially my clothes.
The walls that are attached to the outer tube, have some obstacles to reinforce everything, this is the parts that have a structural compromise by the forces generated by the pressure. Temperature is not a problem here, because the introduction of ammunition, and the pumping of air, gives enough time for everything to cool, and the accumulated heat is not much.
The element that joins the crank with the firing barrel is recycled from a disused fan. It has a captive screw so it does not rotate.
The ajuga to introduce the pellet a few millimeters inside the barrel, is steel, 2.5 mm in diameter, and leaves enough space for the gases to enter the firing barrel.
What follows now, is to build the combustion chamber, when you have time.

[jackssmirkingrevenge]

Looking very nice Hector! I'm very interested to see the level of power with a lead projectile in a tight fitting rifled barrel.

[hectmarr]

I think that with steel spheres and an adjustable retention, with an o`ring, the power is greater, or should be.
The problem with a fluted barrel, and pellet, is that the retention that has, which is always the same, that is due to the drag, can not be adjusted with the increase of the force exerted on the pellet, by increasing the pressure, by having more "X" the hybrid.
With 9 or 10X, the retention is small, in relation to the force applied behind the pellet. Here it is important that the pellet be as heavy as possible.
With bb`s spherical, retention can be increased as the force that drives the sphere increases. It's a subject that I have to confirm through tests, but I've already noticed some of this effect comparing pellet and bb`s in the past. We will see
It is possible to change the firing barrel, without modifying anything else in the weapon, to use steel balls, if I do not like how it fires. In the end it is less expensive, and I have thought about using balls of 7 mm, 8 mm ,3/8, to have a different caliber this time, and not repeat the already built.

[hectmarr]

The component parts that I have already finished, and a picture of what it will look like when it is finished. I need to build the piston and ignition system.

Edited:
Today I manufactured the cover where the ignition goes and the valves, and the piston. They are prepared to be installed in the bank's boiling machine, to make the grooves of the o`rings and to give the necessary exact diameter. I have installed a small bearing on the end of the shaft that is down, to avoid buckling when doing lateral force, when the pieces are rectified and grooved. I will do this work on the weekend.

[jackssmirkingrevenge]

Beautiful work on these, the epoxy-casting technique can provide great results once mastered.

[hectmarr]

Beautiful work on these, the epoxy-casting technique can provide great results once mastered.

Up to now the polyester and epoxy resin perfectly supports the forces generated in the hybrids up to 8X.
A few days ago, I disarmed the HA III that shoots at almost 8x with which I shot many times, I would say 300 or 400 shots, and the piston and cap that delimits the combustion chamber, where the ignition is located, are in perfect condition. I think the fact of incorporating 80 grams of fiberglass mts2 fabric in the central part has helped a lot, because it gives it more resistance. The o`ring have passed the test with good results, equally. For now I continue with this material, which is cheap and I can work without any problem. I imagine that it can take a little more pressure all this.

[hectmarr]

Here are some more photos to illustrate the construction process of this weapon.
The ignition is finished and tested, and the two valves are mounted on the cap of the steel tube head containing the spring and the piston, and have also been tested, it functions correctly :bounce:
It remains to do some things from the bolted system that loads the pellets and little else.
The space between the lid and the piston that was seen in the antepenultimate photo is the size of the combustion chamber. It has a diameter of 32 mm, (the diameter of the steel tube), and 30 mm in length, resulting in an approximate volume of 24 cm3.

[jackssmirkingrevenge]

For someone without "proper" machine tools the quality of the components is superb, bravo!

[hectmarr]

Thank you! Everything is fine in general. I am thinking of using a piston of the car brake system, which are made of metal and could be adapted. I'm looking at the dimensions of what I can find on these sides, that suits what I need.

[jrrdw]

If you have to re-size or adapt brake cylinder pistons I will suggest a very, very sharp clean file. You have made a great choice for durability, these things last for ever. I've rebuilt a boat load of brake cylinders in my mechanical career and the piston cylinder wears out before the piston 99% of the time in my own experiences.