Author Topic: My .257 Condor Build  (Read 1772 times)

rsterne

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My .257 Condor Build
« on: December 04, 2019, 03:12:27 PM »
I got a screaming deal on a good used .22 cal Condor a month ago, c/w a Hawke 6-24 x 50 SF Scope and BiPod…. I have never had one before, so it will be a bit of a learning experience.... As it turns out, I also bought a .257 cal 14" twist TJ's barrel that was 1/2" diameter and 26" long, which I didn't really have a home for, and it hadn't even arrived when I bought the gun.... It was deserving of a good home, so I decided to convert the Condor to .257 cal, it just seems a better fit than a .22 cal in such a powerful platform....

Lloyd Sikes offered me a piece of 14mm ID x 23mm OD carbon fibre tubing for a barrel sleeve, so all I had to do was shim the barrel up to 14mm.... I had a piece of 1/2" ID x 9/16" OD carbon tubing here left over from my Model Yachting days, so I glued that to the barrel and then sanded it down to fit inside the large 14mm ID tube.... I also got a short piece of .45 cal barrel that was 5/8" OD from Lloyd to use as a shim for the part behind the collars that the hammer slides on, and drilled it out to 1/2" ID to slide over the barrel, and Loctite'd it in place.... I made two new collars from 6061-T6 aluminum, turned to fit inside the Condor tube (1.010" OD)…. The front one was drilled out 7/8" ID and the rear one was 1" long, with the rear half drilled to 5/8" like the Condor collar.... but a recess in the front drilled 7/8" ID by 1/2" deep.... I then turned the rear part of the 23mm OD carbon tubing to fit inside the collars, and ended up with these parts....



The back inch of the 23mm CF tube is drilled to 5/8" to slide over the CrMoly tube made from the .45 cal barrel.... In this way, the end of that 5/8" steel tube stops inside the CF tube, and the OD of the tube fits inside the rear collar.... so nothing ends at the same point to spread out any possible bending loads in that area.... The thin front collar is just glued to the CF tube, but it will be screwed to it after the final barrel assembly and all the glue dries.... All gluing is done with Loctite 638, and after it dries overnight, it will get a 3 hour post-cure in my wife's over at 175*F.... I'll have a photo of the assembled .257 cal barrel tomorrow....

Bob
« Last Edit: December 04, 2019, 03:16:58 PM by rsterne »


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steveoh

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Re: My .257 Condor Build
« Reply #1 on: December 04, 2019, 05:42:40 PM »
Now this is exciting! Love hearing about .257’s and wrapping the barrels in carbon fiber.

I saw that Travis is finally working on .257 Raptor builds. Will be interesting to see how they go.
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sixshootertexan

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Re: My .257 Condor Build
« Reply #2 on: December 04, 2019, 09:01:24 PM »
Awesome Bob. I been wanting to build a AF .257 but I have other things going right now.
CCS 2300, CCS 2400, Custom Built Regulated .25, Custom Built PRod Clone, .308 Bullet shooter, XS46U .177, Custom regulated .177, 850 Hammerli .177

rsterne

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Re: My .257 Condor Build
« Reply #3 on: December 05, 2019, 06:22:29 PM »
Here is the completed .257 barrel, along with the stock .22 cal Condor barrel....



The collars are glued on with Loctite 638, along with the CF sleeve and 5/8" CrMoly sleeve in the hammer/spring portion.... The muzzle is threaded 1/2"-20NF to accept a Hatsan Air Stripper or a shot-filled damper.... There is an O-ring on the barrel that pushes into the gap at the front of the Condor main tube.... basically just to keep any dirt out.... The barrel, sleeved with a 23mm OD carbon fibre tube, is about 4 times as stiff as the stock 5/8" barrel.... and yet the assembly is 1 oz. lighter, even though the new barrel is 2" longer....  8)

As in the stock barrel, the four 10-32 set screws that locate the barrel inside the Condor tube tighten against the barrel.... The assembly should be VERY rigid....   ;) …. Here is the barrel installed in the frame....



Bob
« Last Edit: December 05, 2019, 06:56:53 PM by rsterne »
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sixshootertexan

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Re: My .257 Condor Build
« Reply #4 on: December 06, 2019, 10:02:20 AM »
I'd love to see what this bullet would do.
257-112-FN 2 cavity BT
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steveoh

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Re: My .257 Condor Build
« Reply #5 on: December 06, 2019, 10:14:40 AM »
I'd love to see what this bullet would do.
257-112-FN 2 cavity BT

From my experience it looks a bit heavy.
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rsterne

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Re: My .257 Condor Build
« Reply #6 on: December 06, 2019, 03:32:01 PM »
That is certainly way too heavy for the stock valve.... It would take about 4000 psi or maybe more in the 26" barrel to hit the 900s, with a wide open valve, even in a Condor.... My Monocoque .257 can just push them at 950, running wide open on 4000 psi, with a 33" barrel.... Detuned for reasonable efficiency they shoot at 900....

Here is the assembled gun with the .257 barrel, but everything else stock....



Now bear in mind I have never shot a Condor before, so I have no idea what to expect or how to tune them.... I made a guess that with the stock valve the 63.4 gr. BBT FNs I have would be about the right weight, and it was a good guess.... Here is a chart of the velocity at all power wheel settings....



What I didn't expect, and don't understand, is why the velocity decreases, and the report is reduced, at PW 9 and above....  ??? …. Is the hammer driving the breech and top hat so hard it is bouncing off the valve and reducing the dwell?.... Most PCPs simply hit the plateau velocity and then sit there.... In any case, the gun maxed out at 915 fps (118 FPE) with the stock valve, at 3000 psi.... not too bad, I think....  I then ran some strings at various PW settings, with the following results....



At PW 9 the velocities were all over the place, so I didn't include them.... At PW 8 I got only 3 declining shots within a 4% ES, and the efficiency was about 0.86 FPE/CI.... At PW 7 that increased to 4 shots within 4% at 0.93 FPE/CI.... When I reduced the preload to PW 6, the number of shots within 4% increased to 6, at 0.95 FPE/CI, but the velocity was still declining every shot....

A bell-curve developed at PW 5, giving me 9 shots within a 4% ES at an average of 881 fps (109 FPE) and an efficiency of 1.08 FPE/CI.... At PW 4, the number of shots within 4% increased to 12 (the first shot at 3000 psi was too slow), with the average velocity down to 869 fps (106 FPE) at 1.10 FPE/CI.... It looks like a setting between PW 4 and PW 5 would give me 10 shots within a 4% ES, starting at 3000 psi and ending at about 2500 psi....

This gives me a good baseline for my .257 Condor.... As a comparison, my .257 Hayabusa, with its 460 cc reservoir filled to 3000 psi and using a 66 gr. slug, gets 11 shots within 4% averaging 938 fps (129 FPE) ending at 2340 psi, which is 1.11 FPE/CI.... However, it has a 28" barrel and the smallest port is the equivalent of 0.241".... The Hayabusa peaks at 160 FPE with an 88 gr. slug.... To get more power, the Condor will need larger ports (or increased pressure)….

Bob
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steveoh

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Re: My .257 Condor Build
« Reply #7 on: December 07, 2019, 09:29:27 AM »
My Texan with the give or take 72 grain 257420 or the Noe BT of similar weight likes the power wheel set pretty low. I can get a bell curve and about 10 shots. I do wish AirForce had put a numerical scale on the power wheel for my own reference and not for pissing contests.
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rsterne

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Re: My .257 Condor Build
« Reply #8 on: December 07, 2019, 03:28:53 PM »
I have been trying to wrap my brain around the forces on the Condor valve, in particular when the valve is open.... When the valve is closed, it has HPA inside the tank, and atmospheric pressure inside the stem, breech and barrel.... so the force holding the valve closed is the seat area of the poppet times the pressure, just like any other PCP.... However, when the valve is open, but before the slug leaves the muzzle, it is completely different than a conventional PCP....

In a conventional PCP, when the valve is open, there are three closing forces on the valve.... In order of importance:

1. The pressure in the valve throat times the area of the stem that penetrates the valve body (with atmospheric pressure outside)….

2. The drag (or pressure differential) across the head of the poppet, caused by the airflow past it.... This starts out low, and increases as the slug accelerates down the bore and the airflow through the valve increases....

3. The valve spring....

In the Condor (and Texan) valve, however, the end of the stem is not exposed to atmospheric pressure as long as the slug/pellet is in the barrel.... Inside the sliding breech, the pressure is very nearly the same as inside the tank.... This means that there is a force on the top hat (which seals the back of the breech) acting to hold the valve OPEN....  :o …. Here is a sketch I made to show what I mean....



The Breech and Valve Body are in blue, and the Poppet Head, Valve Stem and Top Hat are in black.... The valve is shown open, and I am assuming that the pressure inside the tank, valve stem, and breech is the same everywhere.... This means that the head of the poppet is surrounded by HPA, and there is no force on it in any direction (neglecting airflow for the moment)…. The forces, represented by the teal coloured lines, cancel out.... The valve stem is sealed in the valve body with an O-ring, through which it slides.... If the OD of the stem is a constant, it doesn't matter how big the hole through it is, because the exposed area on both ends (represented by the green lines) also cancels out... This leaves the Top Hat.... The front end of it, which seals in the breech, is larger than the valve stem, where it seals inside the valve body.... This means that a force is generated, represented by the red lines, trying to push the valve OPEN....  :o

If the OD of the stem where it slides through the O-ring in the valve body is "d" and the OD of the top hat is "D", we can calculate that force as follows:

[ (D x D) - (d x d) ] x PI/4 x (Pressure inside the Breech)

For my stock Condor valve, at 3000 psi, I get.... [ (0.309 x 0.309) - (0.246 x 0.246) ] x PI/4 = 0.0274 x 3000 = 82 lbs....  :o

That seems like a very high number, when you consider that the valve spring is only a few lbs. force.... so the fact that the valve closes at all must be due to the drag of the air moving past the poppet and through the valve stem, and the pressure differential that causes between the tank and inside the breech.... That not only reduces the opening force on the top hat area, but adds a closing force as well.... Obviously, this must work, or the valve would always stay open until the slug exits the muzzle and the pressure in the breech drops drastically....

This force, which for a given valve stem OD is dependent on the ID of the breech and the pressure inside it, explains some things about the infamous Condor "tank dump".... For the tank to dump, it seems reasonable to me that this opening force on the top hat must still be large enough to hold the valve open even after the slug has left the muzzle.... That means that the pressure inside the breech cannot escape fast enough through the open bore.... The larger the OD of the top hat (which must be the same as the OD of the barrel stub), the greater the opening force.... Since that OD is the same as the OD of the barrel stub that slides inside the breech, a thicker wall in that area will trap more pressure and increase the likelihood of a dump.... This is because the air cannot escape out of the muzzle fast enough to drop the pressure in the breech, and that increases the force on the top hat, and that overcomes the closing forces on the valve....

Additionally, the opening force on the top hat assists the hammer in getting enough dwell to produce the desired power.... For a given top hat (and barrel) OD, the larger the caliber, the more work the hammer must do to create the shot, because the barrel volume is larger, and as the slug moves down the bore, the greater the pressure drop in the breech, and the less assist to the hammer from the opening force on the top hat.... The opposite occurs with a heavy slug.... It moves slower down the barrel, increasing the pressure inside the breech, which increases the force on the top hat, and increasing the chance of a tank dump....

Assuming my thoughts are correct (and this is only my first kick at the can)…. I think a lot of the variables in tuning a Condor have to do with the relationship between the caliber and the OD of the barrel stub.... and how freely the air can flow through the valve stem.... The bigger and less restrictive the ports in the stem, the less the pressure differential should be (particularly near the end of the shot) and the higher the breech pressure.... This reduces the closing force on the poppet, and should increase the chance of a tank dump....

I look forward to our Condor experts reading through this post and commenting.... I may have it completely wrong.... and if so, I want to know where I made my mistakes....  8)

Bob
« Last Edit: December 07, 2019, 03:58:16 PM by rsterne »
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rsterne

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Re: My .257 Condor Build
« Reply #9 on: December 11, 2019, 01:45:31 PM »
Today I tried installing an O-ring between the Top Hat and the front of the valve.... I had a few thicknesses to choose from, and started with a standard # 010, which is 1/4" ID with a 0.070" Cross Section.... The gun had about 2700 psi in it, so I set the Power Wheel at 5, which if the O-ring was not being hit by the TH should have given me a velocity of about 880 fps, based on the tests I ran with no O-ring.... The velocity was only 760 fps, so obviously that O-ring was much too thick for my .257 Condor.... I removed that O-ring and installed the thinnest one I had instead.... This was a 6 mm ID with only a 1 mm CS.... At the same pressure, the velocity was 872 fps, very close to what I got at the same pressure without any O-ring, so I refilled the gun to 3000 psi and shot a string until the velocity fell more than 4% below the peak.... I then repeated that procedure, but with the PW set at 6 instead of 5.... The results, along with those from the initial tests with no O-ring, are below.... The black lines are at PW = 6, while the red lines are at PW = 5.... The blue line is without O-ring and PW = 4.... The solid lines are without the O-ring and the dashed lines are with the 1 mm O-ring installed.... All lines only show shots within a 4% ES....



There are three obvious differences with the O-ring installed.... Firstly, the peak velocity is about 10 fps less than the same PW setting without the O-ring.... Secondly, the shot count is significantly increased.... Thirdly, the shot strings are flatter (not as peaky), and in fact whereas at PW 6 without the O-ring I had a declining shot string, with the 1 mm O-ring installed I had a bell-curve, although barely.... What you can't see from the chart is that the efficiency also improved.... Here are the average results for the 5 shot strings above....

PW = 6.... 6 shots averaging 879 fps (108.8 FPE) at 0.95 FPE/CI
PW = 6 with O-ring.... 10 shots averaging 880 fps (109.0 FPE) at 1.02 FPE/CI
PW = 5.... 9 shots averaging 881 fps (109.2 FPE) at 1.08 FPE/CI
PW = 5 with O-ring.... 12 shots averaging 872 fps (107.2 FPE) at 1.10 FPE/CI
PW = 4.... 12 shots averaging 869 fps (106.2 FPE) at 1.10 FPE/CI

Just out of curiousity, I also shot 5 shots with an 82.5 gr. slug, with the O-ring in place, a 3000 psi fill and the PW at 6.... I got a declining shot string starting at 3000 psi, averaging 822 fps (124 FPE)…. I also wanted to see what effect the O-ring had on the Power Wheel settings, so I checked the velocity at a 3000 psi fill, with the following results....



As you can see, the O-ring started having an effect on the velocity at PW = 6, initially reducing it slightly as the PW setting was increased.... However, at PW = 9 and above, where the hammer was previously bouncing back and the velocity was reduced.... with the O-ring in place the hammer was slowed more gradually, and the velocity peaked at PW = 11 at 930 fps, instead of at PW = 8 at 915 fps.... The O-ring cushioned the contact between the TH and the front of the valve, and produced a much more normal " velocity plateau"....

In this case, the commonly available American sized O-ring, with a 0.070" CS, was much too thick for my .257 Condor.... I might work fine in a .22 cal where you wanted to detune it and extend the shot string, but all it did was lose me a lot of power.... However, the 1 mm CS O-ring was just about perfect for this gun.... It requires the PW setting to be increased by 1 to get the same velocity, but extends the shot string and increases the efficiency at the same time.... What's not to like.... !?!?!

Bob
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rsterne

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Re: My .257 Condor Build
« Reply #10 on: December 12, 2019, 10:54:25 AM »
For those of you not familiar with adding an O-ring to the valve stem on a Condor, behind the top hat, here is a photo of the tank with it installed.... You don't need to remove the top hat, just stretch the O-ring over it to install it....



Below the valve is a 6mm ID x 1mm CS O-ring (left) beside a standard 1/4" ID x 0.070" CS O-ring to show you how much thinner the 1mm is.... The 0.070" thick O-ring severely decreased the power on my .257 Condor because it limited the valve lift (and dwell) too much....

Bob
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steveoh

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Re: My .257 Condor Build
« Reply #11 on: December 12, 2019, 12:15:31 PM »
My Texan has an O-Ring there. Hmmm. I wonder if that’s stock?
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rsterne

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Re: My .257 Condor Build
« Reply #12 on: January 29, 2020, 03:04:18 PM »
Today I made a degassing tool for the Condor.... It threads onto the valve body and has a stem that can be screwed in to depress the Top Hat to vent the valve....



The body is a piece of 1.25" OD 6061-T6 aluminum bar stock, 2" long.... It is drilled in 1.5" with a 13/16" drill and tapped 7/8"-14 NF to match the valve body.... Then the deeper half of the hole was bored out to 0.88", a bit larger than the threads to form a cavity slightly larger than the thread OD.... It is counterbored 7/8" for 0.10" depth to allow it to screw onto the valve right against the shoulder.... Two 3/32" holes are drilled on a 5 deg. angle in the lip that come out in the cavity just beyond the threads.... and notches filed to vent those holes at the valve body.... The stem that presses on the top hat is made from a 1" long 7/16"-20 NF hex head bolt with the head turned flat and round, and drilled with a size "P" drill (0.323") to a depth of 0.40", and crossdrilled with a 3/32" hole to vent the air from the inside of the bolt to the chamber, where it can then vent out at the collar of the valve.... I cut a screwdriver slot in the end of the bolt so that it can be screwed in against the top hat.... Here is it installed on the valve....



To use it, you back off the stem all the way, and then thread the body onto the valve and tighten it by hand against the shoulder.... You then slowly tighten the stem until you feel it touch the top hat.... A slight amount more pressure and the air in the tank vents out through the degasser, coming out through the slots against the valve shoulder.... Make SURE you don't have your hand near those slots, as the escaping HPA could puncture your skin, giving you an embolism.... As the tank pressure drops, the rate of the air venting slows, and you may have to screw the stem in a bit more.... The tank, and the degassing tool, will get VERY cold as the air vents out.... Once all the air is out of the tank, you can remove the degassing tool so that you can work on the valve....

Now, if somebody will tell me how to remove the valve, I would be grateful…. I have a steel bar that fits accurately in the hole in the valve collar opposite the burst disc, but even with quite a bit of pressure, the valve won't budge.... I don't want to force it, and I assume it is Loctited in place, as there seems to be some glue residue where the valve meets the tank.... I'm guessing that I need to heat the tank, will a heat gun do the job?.... More importantly, is there something I missed?....  ???

Bob
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rsterne

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Re: My .257 Condor Build
« Reply #13 on: January 30, 2020, 03:02:20 PM »
I managed to get the valve off with some heat from a heat gun.... Once it softened the glue and it moved, after that it spun off no problem.... I had a bit of trouble figuring out how to remove the top hat and stem.... The top hat threads onto the stem from the back (bottom side, against the valve), so can't be removed without pulling the stem out of the valve.... You do that by unscrewing the brass collar with the two slots in it to remove the valve assembly from the valve body.... Remove the bottom brass part first, to remove the spring, as that reduces the load on the front collar and it spins out easily....

Once I had the inner valve assembly out of the valve body, I turned the top hat in towards the valve until it touched the 1mm O-ring I had there.... I then used a screwdriver between the top hat and the brass collar to pry upwards a bit, which starts the other end of the stem pulling out of the Delrin poppet head.... Once it moved a bit, I turned the top hat down again, to reduce the gap the screwdriver was in (to keep it working easily) and repeated this operation until the stem pulled out of the poppet.... There were no splines or grooves in my stem, so it wasn't too hard to remove....

Once I had the valve all apart, I had a good look at the air passage in the stem.... The front part is drilled out 0.215", and the rear is crossdrilled with a 5/32" drill from each side to meet almost in the middle.... The air has to make two nearly 90 deg. turns, plus the back edge of the cross holes is shrouded by the conical part of the stem, and the brass valve body when the valve opens.... It is those two holes that feed the inside of the stem I wanted to work on.... I had seen some stems where the 1/4" OD part of the stem was simply milled away on each side, but I had also been warned that if you weaken the stem too much in that area, it will bend or break.... I decided I would use a 5/32" mill on an angle to ease the flow but leave as much metal as possible where the conical part of the stem meets the small diameter area behind that....

The trick was trying to figure out how to hold the stem.... The front part of is it threaded for the top hat, and is larger than 1/4".... so the plan I had of holding that in a 1/4" 5C collet wouldn't work.... I tried to slide a drill stem inside, thinking I could clamp onto that, and found out that the two setscrews in the top hat had dented the inside of the stem ever so slightly.... just enough that it wouldn't slide over a #3 drill, which was the correct size.... I used a fine 3/16" chainsaw file to carefully remove the bumps from the setscrews until the valve stem would slide easily over the stem of the #3 drill.... I screwed the top hat back into place, located it so the dents in the stem were centered in the setscrew holes, and with the stem of the #3 drill in place, tightened the screws.... I positioned the end of the drill so that it was about 1/8" forward of the cross holes... As I thought, the valve stem collapsed just a bit, gripping the stem of the drill to support it.... That allowed me to tighten the setscrews fairly snug without damaging the valve stem.... I then mounted the front part of the top hat in a 5/16" collet, which I installed in a square 5C collet holder, and turned the stem so that a drill placed through the cross holes was at 90 deg. to the faces of the holder.... It looked like this....



I mounted the square collet holder in the milling attachment in my lathe, with the cross holes horizontal.... and with the C/L of the stem on the vertical C/L of the chuck.... I then rotated the milling attachment about the vertical axis until the stem was at a 30 deg. angle to the chuck bore, and mounted a 5/32" end mill in the chuck.... I carefully milled away some material on one side of the stem to change the cross hole from 90 deg. to the stem C/L to just 30 deg.... I went gradually closer to the C/L of the stem until I could feed the mill through into the 0.215" hole in the center of the stem.... At that point, with one side done, it looked like this.... In this end view, looking in the direction of the airflow, you can see how much straighter the flow path is on the right.... In the original setup on the left, you can barely look into the main hole in the stem....



I then mounted the square collet holder on the other side and repeated the procedure.... ending up with the two cross holes penetrating the sides of the stem at a 30 deg. angle.... That basically straightens the airflow from two 90 deg. bends to just a shallow "S".... hopefully reducing the resistance to flow and the turbulence at that point.... The area of the two 5/32" holes is 7% greater than the area of the main hole through the center of the stem.... Here is what the stem looks like after changing the angle of the holes....



There is still quite a bit of metal between the cross holes and the stem to support it.... I'm hoping that is enough strength to survive the rigors of valve operation.... Incidently, once this machining is done, you end up with virtually bore-size passages for a .22 cal Condor.... However, in this .257 cal version the porting is only 84% of the caliber, and 70% of the bore area.... I think I will get an improvement in performance, but don't expect to approach what Doug Nobel gets with his valves.... Fortunately, I have one of those coming to fit a 250 bar (3625 psi) 500 cc aluminum bottle I just happen to have on the shelf.... When I built my .457 Hayabusa, I bought two....  8)

Bob
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Re: My .257 Condor Build
« Reply #14 on: January 30, 2020, 07:24:16 PM »
This evening I did some testing with the new angled ports in the stem.... First I tried all the Power Wheel settings at 3000 psi, with 2 different bullet weights....



I still have the 1 mm Oring in place on the stem, and the top hat was in exactly the same place as before.... The valve acts completely differently.... It is much like a Cothran valve, it either cycles or it doesn't....  :o …. Once the valve is shooting at almost full power, all that increasing the PW setting does is use more air, as you would expect.... With light slugs, there is only 2 turns on the PW to go from 500 fps to over 900, and with the heavy slugs it is even worse, just one turn from 400 fps to over 800.... I shot some strings with the lighter slugs at three different power wheel settings.... I used a 3000 psi fill, as before....



At PW = 5 or 6, it was a declining shot string, with only 6 or 7 shots within a 4% ES.... Yes, the power was increased significantly, but tuning for a decent number of shots just didn't happen.... When I tried PW = 4, the first 4 shots were under 750 fps, then it jumped up to 934 when the pressure dropped to about 2900 psi.... The next shot was faster at 943 fps, and then it started to decline again, with only 7 shots within a 4% ES....

Interestingly, the gun wasn't using much air, the pressure at the end of the strings was between 2670-2760 psi.... That meant that the efficiency was astounding (for a Condor), averaging about 1.4 FPE/CI, compared to 1.1 FPE/CI in stock form (with the O-ring)…. Those strings are shown in the dotted lines above, for comparison.... The longer strings with the stock valve stem are because I could shoot down to about 2400-2440 psi before the ES exceeded 4%....

With 82.5 gr. slugs I got over 138 FPE on the first shot (868 fps) but the velocity dropped about 10 fps per shot, and when I backed the power wheel off to try and get a bell-curve then the velocity suddenly dropped by half.... I never got anything but a declinging string of 4-6 shots within a 4% ES....  :-[

So, I am in a bit of a pickle.... I gained a decent amount of power, but now have a gun that can really only be shot tethered.... At 3000 psi it still won't launch the 66 gr. 257420 HPs I have at 950 fps, which is what I get with my Hayabusa…. It has slightly less air (460 cc instead of 500), and a 2" longer barrel (28" instead of 26")…. but the Hayabusa got a nice bell-curve of 10 shots of 935-948-928 (a 2% ES) with the original valve, and with the new balanced valve I have increased the efficiency about 20% with a slight gain in fps as well.... I was hoping that the axial flow valve in the Condor would make up for the 2" shorter barrel.... but with this valve, that is not the case.... It certainly shows the importance of full bore-area porting, which the Hayabusa has and the Condor does not....

I don't know if a change in hammer weight (lighter or heavier, likely lighter) might make a difference in getting a bell-curve or not.... If anyone has any ideas, or has run into a similar problem with a "high-flow" valve in a Condor, please give me a hint....  ::)

Bob
  • Coalmont, BC