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Author Topic: Check valves  (Read 1787 times)

Offline bill bischoff

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Check valves
« on: September 01, 2022, 12:53:30 PM »
I am building a vintage B Team Racer with a uniflow tank. Normally I use a mechanical overflow tube pincher either on the airframe or the tank itself. In the interest of simplicity, I am considering using a check valve on the overflow instead. I know that people do this, but I have never tried it. Share the benefit of your experience. What brand works best? What are the basic dos and don'ts? Tell me (and others) what I should know.

Thanks.

Offline Motorman

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Re: Check valves
« Reply #1 on: September 01, 2022, 07:18:50 PM »
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« Last Edit: October 02, 2022, 09:10:53 AM by Motorman »

Offline bill bischoff

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Re: Check valves
« Reply #2 on: September 01, 2022, 11:25:34 PM »
I guess I'll go back to plan "A". The red and white ones were made by Fourmost Products.

Offline Les Akre

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Re: Check valves
« Reply #3 on: September 02, 2022, 02:17:38 AM »
I tried them, found they didn't work particularly well. A small spring loaded/ball check valve would be better.

Jed Kusik had a shutoff design on one of his old B tr's where the overflow was pinched off upon resetting the shutoff. It required keeping the shutoff plunger depressed while filling the tank, then when releasing the plunger to be held by the trip mechanism, another piece of wire attached to the plunger pinched closed the overflow tubing.

Many very, very early F2C fill mechanisms operated in this sort of fashion...

Les
« Last Edit: September 02, 2022, 02:47:42 AM by Les Akre »

Offline C.T. Schaefer

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Re: Check valves
« Reply #4 on: September 02, 2022, 05:06:24 AM »
We have used the Foremost on Clowns, TR's, 1 ounce gy, etc. for years.

Offline bill bischoff

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Re: Check valves
« Reply #5 on: September 02, 2022, 06:52:52 AM »
Tom, can you elaborate? Any special tricks or techniques required?

Offline Motorman

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Re: Check valves
« Reply #6 on: September 02, 2022, 02:45:45 PM »
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« Last Edit: October 02, 2022, 09:09:46 AM by Motorman »

Online Mike Hazel

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Re: Check valves
« Reply #7 on: September 02, 2022, 03:49:01 PM »
I have successfully used the Fourmost Products check valve on my Sport racer overflow.  I cut the fuel line it is attached to as short as possible so the valve won't do any funny things. 

Online qaz049

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Re: Check valves
« Reply #8 on: September 02, 2022, 10:42:59 PM »
I am building a vintage B Team Racer with a uniflow tank. Normally I use a mechanical overflow tube pincher either on the airframe or the tank itself. In the interest of simplicity, I am considering using a check valve on the overflow instead. I know that people do this, but I have never tried it. Share the benefit of your experience. What brand works best? What are the basic dos and don'ts? Tell me (and others) what I should know.

Thanks.

« Last Edit: October 26, 2022, 06:48:44 AM by qaz049 »

Offline C.T. Schaefer

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Re: Check valves
« Reply #9 on: September 03, 2022, 05:48:25 AM »
Bill, My older plane has the valve stuck onto the vent line sort of into the wind.  Originally we used a short piece of fuel line with a bb in the end and a slit about halfway through and pointed to the rear.  For filling just push it forward a bit. Worked pretty good for years.  The new plane has the foremost inside with a flush hole  to outside. That works ok too. 
PS  Old plane has a rectangular tank maybe 5/8 wide. Not uni fill.  New plane a wedge with uni .  A bit better I think.  Unfortunately they suffer from lake of use although I did get to fly one in the vintage speed event at Brodak this year.
PS What motor are you looking at?

Offline bill bischoff

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Re: Check valves
« Reply #10 on: September 03, 2022, 04:05:02 PM »
I am going to use a Series 21 McCoy 29, since it has a Dykes ring. I got a new old one off Ebay for about $30. I got an RC version so I could swap different sized venturis easily. Might even do some of that mad scientist fuel experimenting. First step is to make it all work properly.

Offline C.T. Schaefer

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Re: Check valves
« Reply #11 on: September 04, 2022, 05:46:54 AM »
You probably know that you can swap the P/C from the 21 to the older style .29 case?

Offline frank mccune

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Re: Check valves
« Reply #12 on: October 21, 2022, 09:33:53 AM »
     Hi C T:

     Are you sure that these two cylinders will interchange?

     Are you also known as Tommy?

     Stay well,

     Frank McCune

Offline C.T. Schaefer

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Re: Check valves
« Reply #13 on: October 22, 2022, 03:15:42 PM »
Frank.  Yes and Yes

Online Dan McEntee

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Re: Check valves
« Reply #14 on: October 22, 2022, 06:19:04 PM »
You probably know that you can swap the P/C from the 21 to the older style .29 case?

    The old McCoy case needs to be a lightning bolt version, doesn't it?  I just did this in the last few years , only they were .40's, but I don't remember exactly why the old case needs to be a lightning bolt.?? I've slept too many times since then.
  Type at you later,
  Dan McEntee
AMA 28784
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AMA 480405 (American Motorcyclist Association)

Offline Paul Smith

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Re: Check valves
« Reply #15 on: October 25, 2022, 08:26:31 PM »
I guess I'll go back to plan "A". The red and white ones were made by Fourmost Products.

They worked OK for me.  But the air flow rate is a bit restricted so it may take just a bit longer to transfer an ounce of fuel.  The up side is thar it's an off-the-shelf purchase part.
Paul Smith

Offline C.T. Schaefer

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Re: Check valves
« Reply #16 on: October 26, 2022, 04:54:20 AM »
I did a .29  50 years ago when the hobby shop was trying to unload the big block motors for $5 or so. Pretty sure the .29 was bolt in but not the .35. Lightning bolt yes for all.

Offline Al Ferraro

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Re: Check valves
« Reply #17 on: October 28, 2022, 09:50:37 AM »
Tom, can you elaborate? Any special tricks or techniques required?
I use them in Slow Rat and Clown with my wins at the Nats.
Al

Offline bill bischoff

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Re: Check valves
« Reply #18 on: October 29, 2022, 12:15:35 PM »
By the way, these are still available direct from Fourmost Products (Part# 138). It's hard to justify the shipping if you just want one or two of them. I happened to find a few on Amazon with free shipping.

BB


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