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Old Oct 03, 2012, 10:09 PM
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Mini-HowTo
How to make and run a simple pressure bladder

I made this to help control liners in another forum.There is a lot I don't yet know, but I've been very successful with this method, so I hope it may be of some use to RCG members. Besides, y'all taught me most of what I'm doing in the videos.

Part One - making a pressure bladder for a 1/2A plane
http://youtu.be/BNCkngFqPVw?hd=1

Making a pressure fuel bladder (13 min 52 sec)

.............................Full screen is enabled


Part Two - Cranking and running your engine with a pressure bladder
http://youtu.be/o3Evlpf4rG4?hd=1

Pressure bladder cranking and running (8 min 52 sec)

.............................Full screen is enabled
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Old Oct 04, 2012, 06:04 PM
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Thanks RknRusty
That was great. It is worth saving the videos.

Ken
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Old Oct 04, 2012, 09:27 PM
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Originally Posted by greyflight390 View Post
Thanks RknRusty
That was great. It is worth saving the videos.

Ken
Thanks, it's not 100% thorough, because I'm new at it too. But it should get anyone going that's trying to get started with a bladder. When I first started trying bladders last year, I had to compile ideas and opinions from several websites and pick out what seemed to work for me. That's all I have now, but it's simple and dependable. So I hope this de-mystifies it for some people. It's so easy and cranks and flies so well that I see no reason to ever use a hard tank again. They are just too much of a pain in the ass. The difficulty of using bladders is a complete myth. Thanks to Bare and Andrew, among others for getting me interested.

If enough people think it's good enough to sticky, I'll ask a moderator.
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Old Oct 05, 2012, 01:29 PM
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There is also a thin walled bladder some people are using called the 'Little Red Cap' that is pretty much like a condom for a kitten. It is made for covering a caulking gun tip. It puts out much less pressure and is easier to needle. It is good for maybe up to a .15 size motor. A pack of 20 is about$5. I noticed you were filling past the filter. The dirt will still go in the motor. You did an efficient job starting there. I always take about three tries to unclamp the hemostats in time.
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Old Oct 05, 2012, 03:08 PM
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You caught me, Aspeed, I'm busted. As anal as I am about clean fueling, I'm a little embarrassed that I let it slip in the video.

The line I stick on the end of my syringe usually has a Dubro filling station filter on it(always when I'm in the field). It was occupied with the MP Jet fuel tank on my test bench so I omitted it for the video.

When it's on the fueling line, before I lift it out of the bottle I give it a punch to backwash it and then pull it off of the barb, let the last bit drain from it and then lay it on the clean rag next to my fuel bottle. After pushing the fuel into the system, I usually let a bit squirt out before I plug the line onto the engine. That helps get any air out of the tip of the line too.

You are right, cleanliness is the most important part of everything.
At least I mentioned flushing the NVA after use.
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Old Oct 05, 2012, 09:32 PM
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Perhaps you might consider just tying a Knot in the dead end of the Bladder tubing.
Easy and proven for decades
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Old Oct 06, 2012, 08:07 AM
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Yeah, that works. I have a thousand .22 pellets and I'm low on tubing so tried not to waste it. I can stick a pellet or an aluminum plug in almost as fast. One of the latex tube sellers says to tie your whole tube stock into sections when you first get it, then cut off a section when you need a new one. Maybe they're trying to get us to use it up faster.
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Old Oct 09, 2012, 01:50 PM
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Thanks for the video, RknRusty!

Here's another take on the same subject: http://www.clcombat.info/bladder.html

Note the simple fuel shut-off.

They also mention using Monoject syringes. I've found this brand the only one that doesn't deteriorate using glow fuel. The Luer lock and barbed nipple is a secure way of filling without the tube blowing off.

Norm
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Old Oct 09, 2012, 08:14 PM
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Quote:
Originally Posted by Norm Furutani View Post
Thanks for the video, RknRusty!

Here's another take on the same subject: http://www.clcombat.info/bladder.html

Note the simple fuel shut-off.

They also mention using Monoject syringes. I've found this brand the only one that doesn't deteriorate using glow fuel. The Luer lock and barbed nipple is a secure way of filling without the tube blowing off.

Norm
That was one of the most helpful articles I read while I was figuring out how to make and use a bladder. I read all I could find and made note of all the things that fit my idea of what I needed. That's where I got the pellet Idea, which was lucky because I already have a .22 Benjamin pump varmint air rifle.

In re-reading it just now, I realized he trains his bladders to expand at the rear. I train mine at the front. But the Texas Timers pickup fitting causes it to naturally expand in front, and because of this it traps any air away from the pickup hole. It has been working fine for me. I only use 3/4 to 1oz for my Tee Dees, and only ever get a BB sized air bubble when filling from the front.

I searched but never found a video on the subject and it took a while for me to get what I use now in a simple form. I over-thought it at first and my early ones were cumbersome affairs with a check valve in the tail for filling, and a Tee for an air bleed. When I realized filling from the front eliminated the necessity of all that other silly stuff, I ended up with what I use in the video.

I neglected to use a filter in the video when drawing up the fuel, which I always do in the field. I also didn't mention that I let a little fuel squirt back out before connecting it to the engine, so as to backwash the filter on the plane. I buy 30cc/1oz Becton Dickinson Luer-Lok syringes from a local medical supply store very inexpensively. I still need to attach an on-board pinchoff.

But all in all, I think my movie will help some people figure it out more quickly than I did, especially those, like me, with no flying buddies whop know all that stuff. I'm glad you liked it. So far nobody has seriously shot down any of my methods.
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Old Oct 10, 2012, 01:32 PM
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We wouldn't shoot you down? I thought I should add that the F2D FAI combat planes have a nice shutoff that shuts off the fuel when there is no centrifugal force. They are kind of a "safety forced" thing, but are kind of handy when starting as they shut off the fuel normally and there is a big lever with a weight that can be pushed quickly once running or to give a quick prime. A spring loaded latch is used until launch. They are about $15 to $40. An electrical toggle switch can be used to squeeze the tubing until it starts too. I have been wanting to try this, but haven't figured out a clever/subtantial bracket yet. Oh ya, and I don't get the extention for the syringe. I just cut the outside sleeve with the threads off carefully with an Exacto knife.
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Old Oct 10, 2012, 02:51 PM
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I've read about those shutoffs, and saw descriptions of several people's different methods. But I didn't know they were for sale, I had thought they were all homemade by the combat flyers. I wouldn't want it to kill it if the lines go slack from a momentary gust of wind or something. Maybe the sensitivity can be adjusted?
I should take another look at those. And I'd be interested in seeing the electrical shutoff, maybe I could come up with a way to mount it.
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Old Oct 10, 2012, 05:40 PM
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Only thing I want to add is: WEAR your SAFETY GLASSES AT ALL TIMES when dealing with fueling or running motors.
The fuel in the eyes is bad enough; one thrown prop blade can ruin not just the day, but the rest of your (or someone else's) life as well.
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Old Oct 10, 2012, 06:47 PM
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Quite right, JK. I only gave them a cursory mention.
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Old Oct 10, 2012, 09:34 PM
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Quote:
Originally Posted by RknRusty View Post
Quite right, JK. I only gave them a cursory mention.
Don't mean to preach, but your eyes are your most precious gift from the divine- guard them well. Without them, you can't work or play, look at your wife or children, or enjoy any of the fruits of your many years of hard labor- guard them well. Only one set to a customer and once gone- GONE.
Your ears are next in line, wear your hearing protection when running motors!
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Old Oct 10, 2012, 09:47 PM
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Sometimes I wear a helmet too, even when the rules don't require it. I got the cowboy hardhat for the sunshade too. I got the cheaper nylon shutoff. I have heard they break much easier than the aluminum one for $40. I still haven't tried it out yet, but have seen them go. Our club isn't all control line friendly. I don't think the motor would quit if the lines go slack. Maybe it is a good thing if it is that slack, it won't hit so hard.
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