Pressure bladder how-to videos, parts one and two

Thanks. I had no idea, lots of little parts but simple enough.

Rusty,

if someone can't make a bladder tank after that, well...

It's amazing that you did not get damage when you clipped that tree! :-)
That's a strong BFS.

George

Great, I'm glad it meets y'all's approval. Regarding those "lots of little parts," most can be improvised. The end plug can instead just be a knot tied in the latex tube. The feed fitting could be a section of plastic silly straw or brass. I do like the Texas Timers fitting because the shape keeps any air from entering the line until it's almost out of fuel, and that gives me one or two laps warning to prepare to land. A lot of people make wing compartments for the bladder but my 1/2A planes don't have much room in there. My little fishnet bag isn't a big aerodynamic problem... and it looks sexy.

I should have mentioned, store your latex tubing in a airtight bag and out of exposure to light. It can degrade if not protected.

I'll try to get part two made in a day or two. Cranking and needling is easier than with a hard tank.

Thanks for your efforts Rusty.

I'm about to build a "Pinto" 1/2A stunter and plan to run it on a bladder tank from RSM. RSM also offers the "small parts" that you mention in a separate kit.

One of my TD .051's will be mounted inverted in the "Pinto" and the engine will be largely covered by a cowl. This will be an extremely sharp airplane and it will be covered with a synthetic material soon to be determined.

Jury's still out on which one I should use. Suggestions?

SuperDave wrote:Thanks for your efforts Rusty.

I'm about to build a "Pinto" 1/2A stunter and plan to run it on a bladder tank from RSM. RSM also offers the "small parts" that you mention in a separate kit.

One of my TD .051's will be mounted inverted in the "Pinto" and the engine will be largely covered by a cowl.  This will be an extremely sharp airplane and it will be covered with a synthetic material soon to be determined.

Jury's still out on which one I should use.  Suggestions?

Regarding covering, absolutely positively ***Ultracote is my preference. It's much easier to use and retains more shrinkability for later on if you develop wrinkles. I'll try to look up the Tube videos that helped me the most and post the links for you.
EDIT:(***Not any more. I'm a Monokote user now)

My first Ultracote job turned out really nice without even one practice run. It responds to the iron temperature at specific temperatures that are far enough apart so you don't accidentally shrink while you're only trying to set the adhesive. And you really don't need a heat gun with it to do the final tightening.

The only thing I like Monokote for is laying on trim colors. They will glue down with only Windex, which will not activate the Ultracote glue.

My year old Li'l Satan had some loose covering and a slightly twisted wing. Last week I fixed both with the iron in a few minutes. It had plenty of shrink left in it.

Part two - Cranking and running with a pressure bladder. I posted it in the first post too since they go together. I'll make a playlist so #2 automatically plays right after #1.

My apologies for the crappy video quality. I still had the camera set for indoor lighting after Sunday's birthday party.

I have two questions.
The first is for those of you who may have more experience with running pressure bladders. When I get ready to launch my Streak with an .051, I find peak speed and then back off richer until I just barely hear the first crackle. Not nearly as rich as I set a Bee on suction. If I set it any richer it will perform poorly. But after I launch I make two flat laps and the engine gradually speeds up a lot faster and then runs very well for the full flight. Could this be because I run a larger prop, 5.5x3 instead of the Tee Dee favorite of 5" or so, or is this what I should expect from pressurized systems?

Next question: I think I may already have answered it. My newest Tee Dee on the Satan with the brand new NVA, needles out at 1.3 turns and super sensitive. The Streak is 3.5 and the Chopper is 2.5 turns. I was surprised at the low setting of 1.3 turns was. As I was thinking about writing this post I remembered I had forgotten to bore the venturi. Would that explain it?

I certainly don't have all the answers. Thanks,
Rusty

Good stuff Rusty, this thread should be stickied...... Hint, hint.

Ron

Hello Rusty, after watching your video I'm not sure how easy this would be to do. Prior to launching our combat planes, we quickly pinch the fuel line. This will ultimately lean the engine. If the engine doesn't lean and it wants to stall, open the needle some more. We keep opening the needle until we get the engine running rich and a quick pinch leans the engine rapidly. Don't set your needle with the plug wire attached . I like to run the engine a few seconds to get some heat into it as well. A finger on the case lets me know if the engine is getting warm. Higher nitro makes the needling easier as does a smaller prop. I also have someone holding the plane which makes it easier as were always paired up with a pitman. I do understand that not everyone has that luxury.

No matter what you do, your going to get some false pressure in the bladder. I like to purge the bladder prior to running. I didn't see this in the video. After the bladder is full, I point the venturi towards the ground as you explained and I open the clamp. In my case, I use a slide line clip which stays on the fuel line. This not only allows me to see the drip as you mentioned, it bleeds out any air in the bladder which will also affect your run until it finds it way out. You certainly could make your bladder slightly longer and this would help as the initial pressure wouldn't be so great. The higher pressure results in a richer run until the pressure is bleeding down and then it will lean out throwing your initial needle setting off. Making sure all fitting are air tight is critical such as the black friction sleeve on the needle. Ken

Ken Cook wrote: Hello Rusty, after watching your video I'm not sure how easy this would be to do. Prior to launching our combat planes, we quickly pinch the fuel line. This will ultimately lean the engine. If the engine doesn't lean and it wants to stall, open the needle some more. We keep opening the needle until we get the engine running rich and a quick pinch leans the engine rapidly. Don't set your needle with the plug wire attached . I like to run the engine a few seconds to get some heat into it as well.

I'll try that pinch test before i get ready to launch. I do let it warm up before I give it the final set.

Ken Cook wrote: I like to purge the bladder prior to running. I didn't see this in the video. After the bladder is full, I point the venturi towards the ground as you explained and I open the clamp. In my case, I use a slide line clip which stays on the fuel line. This not only allows me to see the drip as you mentioned, it bleeds out any air in the bladder which will also affect your run until it finds it way out.

There's only ever a BB sized bubble and the shape of the Texas Timers insert traps any air around it and there's no way you can get it to enter the line before it's almost empty(I've tried and it just floats up past the fitting a half inch from the inlet and won't go in the hole). Neither of the planes I run this system has ever coughed during flight. The recent problem I had with the Stuntman23(aka the Chopper) shutting off turned out to be the head, and it hasn't missed a stroke since I changed it. I used to put an additional air bleed on the tail of the bladder to let it out, using one of the orange Luer-Lok fittings sealed with a screw-on cap. TT doesn't sell the caps but I can get as many as I want from the dialysis clinic if anybody wants them. I quit using it as there was never enough air to get into the line before the bladder emptied anyway. I think I sent Ron a couple of caps if he wants to do that.

Ken Cook wrote:You certainly could make your bladder slightly longer and this would help as the initial pressure wouldn't be so great. The higher pressure results in a richer run until the pressure is bleeding down and then it will lean out throwing your initial needle setting off.

I used to make them twice as long. With the size I make now, there is still room for more after I fill it, but maybe I need to add a little more tube. I've never had the mixture change after it hits top speed, except 2 laps before it shuts off. That may be the elusive air bubble. I'll make some longer ones and see if they work better.

I guess my movie wasn't thorough enough to stand on its own without a discussion thread to accompany it. I'm still new at it and have never seen it done in real life besides my own.

Rusty, I thought your video was excellent. I certainly couldn't of done better. Good info and good advice. I enjoyed watching it. For those of us that have never experienced using a bladder, it's a must to try as the runs are impeccable and using these are even easier than a tank. My hats off to you for a well done job. I do get a lot of air in my bladders. I'm filling from the rear forward and this would certainly do that. I will try your method. I think you also benefit from a steadier run as opposed to mine due to yours being in the cloth bag. I'm so tightly packed into a plastic tube it squeezes like a clamp. Ken

Excellent video Rusty! I just ordered supplies from Texas timers. I'd really like to be done sticking planes in the ground because fuel pressure craps out. I guess I'm going from carburated to fuel injected?

JPvelo wrote:Excellent video Rusty! I just ordered supplies from Texas timers. I'd really like to be done sticking planes in the ground because fuel pressure craps out. I guess I'm going from carburated to fuel injected?

Yep. On a car we'd call it TBI. Throttle body injection.
With the TT feed fitting, the pressure begins to crap out a couple of laps before it shuts off so you have a couple of laps to flatten out and prepare to land. No more Surprise, I'm falling and I can't get up!.

If you need a one ounce syringe with a Luer-Lok fitting, let me know and I'll send you a couple. I buy them cheap at a medical supply store in town for about a buck or two each. 3/4 ounce usually runs my Tee Dee for 2 or 3 minutes. You'll have to pioneer the reedy cranking procedure for us.

Texas Timers sells stuff mainly for free flight use, so those bladders are a little on the small side. They're OK for 1/2-A use, though some people like bigger bladder tubing (5/32" or 3/16" i.d. x 1/32" wall fits the bladder compartments people who fly 1/2-A combat tend to use). If you don't want to use the Texas Timer fittings, plain old pop rivets (on the fuel tubing end - remove the center spike, of course) work pretty well. On the plug end, people often use fired .22 brass. Pieces of large diameter o-ring work, too. For bigger bladders, I like the hole plugs they sell for timed irrigation systems (Ace carries stuff like that). Rubber bands or cable ties work also in place of the clamps.

For big models 1/4" i.d. x 1/16" wall tubing works nice. For fuel tubing, get stuff you can squeeze - some RC silicone tubing is too hard or has too thick a wall.

McMaster Carr (www.mcmaster.com) is a good source of a lot of things, this includes latex tubing. The black stuff actually works better, being UV-resistant. Phil Cartier also sells some natty fluorescent colored stuff. I used to sell tubing, too, when I was in the US.

Iskandar

iskandar taib wrote:...For big models 1/4" i.d. x 1/16" wall tubing works nice. For fuel tubing, get stuff you can squeeze - some RC silicone tubing is too hard or has too thick a wall....

TT does sell tube with an OD of 5/16", an ID of 1/4", and 1/32" wall thickness. It gives more pressure than my 1/2A tube. http://texastimers.com/accessories/large_bladder_tubing.htm

In the video I used dacron to tie it off, but it's a pain in the axe. Waxed dental floss is much easier and I've been mostly using wire lately. It has the best record for passing the leak test the first time.

On my Li'l Satan there is little room for the TT fitting and a tube to plug into a filter. Then the carb feed line is so short there's nowhere easy to pinch it, so I've just been plugging the filter straight into the bladder tube and tying it off. So far it works fine. Due to laziness I've just been knotting the tails too.

Yeah, for 1/2-A bladders people will often just tie a knot in the tubing on the closed end. Tieing the knot also trains the bladder to fill from the far end, since you stretch the tubing to get the knot tight.

Larry Driskill likes to use really long, thin bladders for 1/2-As, or at least he did when he was selling Light Hawk kits. I think he did what you did - the bladder tubing also serves as fuel tubing.

Iskandar

I don't know if this helps but when my dad and I were doing it we used ping pong balls and ink pen bladders. We used Kirn Kraft needles
on the Tee Dees.

Hi and welcome to CEF.
Some people still use pen bladders when they can be found. I think those are mostly larger than 1/2A applications. The thin latex is just my personal preference for sport flying, and a single bladder can be reused a few times if you flush it with alcohol. I've heard of ping pong balls, but not sure how they're used.

I wish I had known more when I made the videos, I kind of over complicated it. All that string tying and such. JP_Velo, Jim, uses o-rings to secure the latex tube to the outlet. I like to stick a Fourmost 1 way valve in the tail end of the bladder and fill it from there. Still have to train it to expand first from the front. I am still fond of the Texas Timers cone shaped front piece as it keeps air from getting sucked in until the very last seconds.
Rusty

I just watched my videos again. Been a long time, but not as disorganized as I feared. Some things are easier than I made out. I always use steel wire ties on the cone end and on the 1-way valve in the tail. Pretty much nothing else has changed. I've been meaning to get some tiny o-rings for securing the ends but forget whenever I go to Lowes.

BTW, that old Baby Flite Streak is still a marvelous flyer. Same engine as when I filmed the bladder movies. Only now I put the bladder bag on top of the inboard wing. Makes it easy to access and pinch off with your thumb where it passes over the top of the fuse.

Jim if you read this, tell us what diameter o-ring. I'm guessing 1/8".
Rusty

RknRusty wrote:Hi and welcome to CEF.
Some people still use pen bladders when they can be found. I think those are mostly larger than 1/2A applications. The thin latex is just my personal preference for sport flying, and a single bladder can be reused a few times if you flush it with alcohol. I've heard of ping pong balls, but not sure how they're used.

I wish I had known more when I made the videos, I kind of over complicated it. All that string tying and such. JP_Velo, Jim, uses o-rings to secure the latex tube to the outlet. I like to stick a Fourmost 1 way valve in the tail end of the bladder and fill it from there. Still have to train it to expand first from the front. I am still fond of the Texas Timers cone shaped front piece as it keeps air from getting sucked in until the very last seconds.
Rusty

Rusty we used ping pong balls on our combat plane the center ribbs were skinned. I was like 11 or 12 when my dad built them. he just cut a hole and glued a ball then drilled a hole for the bladder to go in. I don't recall how long they ran but I think it was enough.

schiada96 wrote:Rusty we used ping pong balls on our combat plane the center ribbs were skinned. I was like 11 or 12 when my dad built them. he just cut a hole and glued a ball then drilled a hole for the bladder to go in. I don't recall how long they ran but I think it was enough.

Must've been 1/2A for a bladder small enough to fit in a ping pong ball, am I right?
Rusty

Great, great presentation of using the bladder. I went thru comments and such, I don't think you overcomplicated at all. Right on the money for amount of info, time spent watching. Thanks for the share - it helps preserve the hobby.

Great info passed down to future generations of builders and flyers! Nicely presented and then the follow up showing the use of the bladder is just great!