where to get the components and how to run them, added Saturday,
August 21st, 2004
make, set up and run consistently on an SSC engine than a
plastic clunk tank. What follows is a time proven system for
bladders. If you follow these instructions and hints you will
be successful running a bladder system.
Here is exactly what I do with the OS LA .15 on a pressure
bladder:
You need to have the right tubing to make your bladder
tank. It cannot have too much or too little pressure. I use
tubing from McMaster Carr www.mcmaster.com
The bladder tubing:
Go to McMaster Carr on line, then go to Catalog Page 97,
which has Natural Rubber Tubing, Part number 5234K44,
1/4" ID with 15psi pressure rating, $ .66 per foot in 15' and
25' lengths. I cut mine to 3-1/4" for SSC. This holds 3-1/2 of
fuel and is nowhere near filled.
The tubing from bladder to engine:
Catalog page 97, Part number 5234K93, 1/16" ID, 25psi,
$.59 per foot in 10' and 25' lengths.
Fittings for connecting the bladder to the engine:
Catalog page 111 - Barbed Tube Fitting, Tube to Tube
fittings (nylon). This is used in the thin fuel tubing from the
bladder to the engine. I use it at the point where I open the
line to fuel and defuel. 1/8", Part Number 5463K333, $3.81
for package of 10.
Plug for bladder end:
End Plug for rear of the bladder. Catalog Page 112, Barbed
Tube Fittings, Plugs - 1/4" Part Number 5116K113 $2.02
for package of 10. Use a small tie wrap (larger ones leak) to
hold this in the tubing. It has a barb on it that the tie wrap
will cinch up to and it can be over and over.
Reduction fitting for front of bladder to fuel line:
Reducing Coupling to connect bladder to the line to fuel
tank. Catalog page 111, Reducing Coupling, 1/4" to 1/8"
Catalog Part Number 5463K628, $5.71 for package of 10.
The 1/8" barbed end fits well in the 1/16" ID tubing. Attach
to the 1/4" tubing with small tie wrap.
Now - how to use it:
1. There is no need for a reducer in the fuel lines.
2. There is no need for a fuel shutoff, your carb will kill the
engine when you close it completely.
3. Fill with two, two ounce syringes. One filled to the max,
the other to 1-1/2 ounces. The end fitting on the syringe is
the single most important accessory. It has to go into the
1/16" tubing without slipping off when you fuel. Because I
could not find 14 gauge needles when I needed them I used
a length of 1/8" brass tubing with the next size smaller brass
tubing slipped into it and the soldered into place. It has
worked well for over a hear.
4. Connect the fuel tubing to the engine spray bar by running
it to the fitting that normally goes to the carburetor. This is
backwards, but it holds pressure better.
5. Set needle vale to 3/4 turns open, this is probably a rich
setting.
6. Prime, start and enjoy 7 minutes of rock solid run time.
Make sure your bladder and your fuel lines are not kinked or
distorted. You will have inconsistent runs if they are. Just
before the bladder is completely empty the engine will richen
up slightly. You have about 20 seconds of run time from this
point till it quits.
I have used this set up over several weekends on the same
bladder. I only change them when I go to a contest.
A 140cc or 5oz syringe is available from California Vet
Supply @
http://www.calvetsupply.com/index.asp?PageAction=VIEWP
ROD&ProdID=414
This allows you to fuel the bladder with just 1 syringe. Be
sure to use a barbed fitting on the syringe to avoid the fuel
line sliding off the nipple during fueling.
Created by Lou Melancon. Edited and distributed by David
McGinnis.
The bladder tubing is 3.25". An inch of this
tubing will hold up to two ounces of fuel.
Note that the tie wraps are the small size.
Larger ones will leak, use the small size.
one end and 1/8" at the other. Available
from McMaster Carr. See text for more
details. The 1/4" end plug is shown
below
filler on the end. The text has more details
on this setup. I actually have four syringes at
a contest. I fill during the one minute before
start engines. This leaves me with two more
filled syringes in case a bladder bursts or I
dirtnap on launch and have to refill quickly.
Shown below is the end of the syringe that I
used for filling . The text has details on
making up this "needle" if you cannot find
14 gauge hypodermic needles.
call to start engines it is nice to have a fuel
line clamp. This one is manufactured by
David McGinnis and is made from HDPE
with a sewing bobbin as the axle. My first
ones were made using the bobbin and poplar
wood bought at home depot.