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PostPosted: Sat Oct 10, 2015 10:42 pm 
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Joined: Thu Oct 01, 2015 3:40 pm
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Location: California, USA
I’m getting ready to try to “detune” a .22 Hatsan AT44-10 (standard length tube). I’ve spent hours searching for and reading threads on this subject. It appears the three simplest and least expensive ways are the “Sail” mod., plugging the bottom five holes in the valve and replacing the “full power” .100” valve stem with a larger one (.150 or .140 or modify one to the size you want). Some of the information indicates that the "sail" mod should be the first to be attempted.

I have seen tests and projections on shot count and power on the valve plug mod and the larger stem mods but can’t seem to find any test/figures on the “Sail” mod. Can someone direct me to links where there is some information (figures) on how the size of the “sail” affects velocity and shot count?

I’ve been given some good information on a couple of starting point sizes for the “sail” (.425 to .495) but I cannot seem to find any corresponding information on how many shots one could expect by adding a .425” sail or a .496” sail.

So I guess this is actually two questions. 1. Does anyone know about how many “good” shots I can get by adding a .425” sail and about what kinds of velocity I can expect from standard weight pellets (14-15 gr.)? 2. Can anyone direct me to some links where someone has tested different size sails and posted their results?

I would be very grateful for any information on this subject. I also apologize in advance if this information is already out there but that I have been unable to find it. Thank you.


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PostPosted: Mon Oct 12, 2015 7:18 pm 
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Joined: Mon Mar 09, 2009 6:46 pm
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Location: r Alberta
I made some sails and tried different ones till I got what I wanted. I don't know of any info as to size that will give you a specific result. I wanted a higher shot count and it worked for me.


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PostPosted: Mon Oct 12, 2015 11:38 pm 
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Location: Canada
Just my .02....stop obsessing and just try it. If you don't like the result, this mod is 100% reversible with no damage to the valve body. You've NOTHING to lose but a little of your time.

Al


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PostPosted: Tue Oct 13, 2015 12:29 am 
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Location: California, USA
Thanks for the replies guys. Actually I'm not obsessing about it, just trying to save some time and decrease the number of times I have to take the gun apart to try different "Sails". That's one of the points of this forum is to obtain information from "those who have done it before" so others don't have to spend a lot of time figuring out what someone else as already done. If someone has already tried a .425 sail and it is getting him the numbers I'm looking for then that's where I'm going to start. If someone is getting the numbers I'm looking for using a .460 sail, then that's where I'll start. I would also like to get at least a general idea of how much of an increase in shot count (and decrease in velocities) some people are getting with this mod. Are they getting 40? 50? 60? shots at 700 fps on a fill? The information may be out there but I can't find it.

Plasticman: After adding your sail, how many good shots were you getting from a fill? Do you know the average FPS you were getting and was it a .22?

Thanks for the information. I also have to make a confession. I can't try my AT44 right now because I broke the fill adapter and the new one won't be here for a week. I figured if someone had a sail size that was working for them, I could at least make a couple similar in size range while I was waiting for that darn adapter to get here. Patience may be a virtue but it's a pain in the rear when you don't have any. :)


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PostPosted: Tue Oct 13, 2015 9:02 pm 
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Location: Rocky Mtn Hse Alberta
I can change a sail in less than five minutes. Too long to try?

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PostPosted: Tue Oct 13, 2015 10:19 pm 
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Location: P.G. B.C.
Make it .020" smaller than the rear inside of the valve body. Done. Closing off the bottom holes with set screws will also increase the shot count by reducing the wasted air- or so I think I remember it being stated.

As Walter says, do it.

Do you need someone to make the sail for you?

If not, just dive right into the job & do it.

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Daryl


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PostPosted: Sat Oct 17, 2015 6:44 am 
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Joined: Fri Oct 10, 2014 4:29 pm
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Location: Nova Scotia
[quote="Daryl"]Make it .020" smaller than the rear inside of the valve body. Done. Closing off the bottom holes with set screws will also increase the shot count by reducing the wasted air- or so I think I remember it being stated.



Do you need someone to make the sail for you?


If someone was making them they would probably sell a few...to the non-mechanically inclined among us :-)


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PostPosted: Sat Oct 17, 2015 2:39 pm 
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Location: California, USA
Sounds like I’ve somehow irritated some people and I’m not sure why. The reason I was asking for additional information for a starting size for the OD of the sail is that in a PM, Walter told me to start with a sail about .425”. That would be too big to put in my AT44 valve because the ID is only about .410”. His later suggestion to make it about .060” smaller than the ID of the valve gave me a good starting point as did Daryl’s suggestion of starting with a .020” smaller OD sail. My main concern was to reduce the amount of times I would have to pry out the white plastic press fit sleeve on the valve end. I thought that prying it out too many times to try different sails might damage it. Anyway, I’m sorry if I asked too many questions.

I did find a metal washer in my parts drawers that might work. It’s only about .032” thick but I’m going to give it a try. I drilled it out with a 9/64” (0.140”) drill bit and enlarged the hole slightly with sandpaper on a small wood dowel to about .155”. The OD of the stem where the washer fits over is about .154”. The OD of the washer was already .370” which would make it about .040” smaller than the ID of the valve. Walter suggested .060” and Daryl suggested .020” so I figured I was in the ballpark. I can’t give it a try until my air fill adapter comes in so in the meantime, I’m going to try to find some more washers. I already tried three hardware stores and none had anything with a small enough center hole that could be drilled out. I’m going to start off making two more: .390” and .350”. I’ll let you know how they work out.


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PostPosted: Sat Oct 17, 2015 7:33 pm 
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Joined: Mon Dec 29, 2008 9:50 pm
Posts: 828
Location: Scotland,Ontario
Try Fastenal for washers they are great, though here you need to have an account.

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Deal with local or small business,they treat you way better than the big chain stores!


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PostPosted: Sat Oct 17, 2015 8:05 pm 
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Location: Victoria, BC and Clarkston, WA
topher1266 wrote:
Try Fastenal for washers they are great, though here you need to have an account.


Not necessary, just tell them you work for MOD, Ministry of Defence. You'll get the maximum discount. I was told this by the guys in the Victoria Fastenal.

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Mrodair CP-1M .22 and .177


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PostPosted: Sun Oct 18, 2015 9:53 am 
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Joined: Mon Sep 05, 2005 10:55 pm
Posts: 6845
Location: Rocky Mtn Hse Alberta
Don't sweat the small stuff :-)

My apologies that .425 must be for the larger BT65 valve. Try a few sizes and keep track of results. Learning is part of the fun
Cheers

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