Scary stuff I was wincing in fear!

Thanks for the info guys.  The bottle is an oil bottle sold for spinning wheels, my wife is into fiber arts. They are advertised as a half oz of oil, but come about three quarters full, so I'm guessing it's about 18cc's full capacity.  The drawing you did is exactly what I had in mind.

I have a 0.50 carb from EX and an aluminum carb body I am considering using.  Search is on for test tube stoppers.  I've only got one bottle (well two if you count Mama's wheel bottle, but I like dinner too much to try confiscating that one), so I'm not going to experiment too much with melting holes quite yet Kris.  I'll try that with another model.  Thanks for the tip!  Sound's like a good one.

That's what I was thinking about the the spring post pressure tap.  Thanks Brad, you saved me from messing up a perfectly good crankcase.  Do you have a source for a muffler that's compatible with a pressure tap?  I'm guessing that adding one to a throttle type isn't feasible.

Hey that's great you have a RC carb it's a good investment.
The test tube stopper is called "bung" proper name for them.
What size is the ID in mm with the aluminum cap removed?
Make sure you get the right size metal tube not the catch all size typically used
in fuel tanks for your tank think 2mm ID tube approx .08" anymore than that
for a 1/2A .8cc / .05 engine is over kill.

Muffler:
Option 1:
http://www.exmodelengines.com/product.php?productid=18099&cat=267&page=1
Note where the cylinder exhaust ports are in relation to where you wish the mufflers exhaust to exit
to best clear the plane. Then tap and install a pressure nipple right where one of the cylinder exhaust
ports are. You want to select the one furthest away from the mufflers exhaust hole for best pressure.
Note you can add a header to this with care using all thread tube and two thin nuts.
For the pressure nipple you want a small one suitable 1/2A size. If you need to source
one look for one with 1.2 - 1.5mm ID

Option 2:
http://www.exmodelengines.com/product.php?productid=17862&cat=267&page=1
This is more restrictive / will require you to use a round file and open up the exhaust exit
more right at the manifold where the header starts. There is plenty of excess extra effort here
will get you some more power.  The reward is better goo control and you can put the pressure tap
directly on the header. Go back to page 1 reference the work I did to open up the muffler for better breathing.

Stopper Bung - free shipping recommend buying at least two for future project!
Note shop for best price I like this link as it shows you the size dimensions, from there you can price shop.
Pick out a bung that the center dia. will be a snug fit into the bottle top fit it in place and see just how deep in
it goes before razor blade slicing the excess length for a nice proportional fit.
Drill two holes undersized so it it snug on the metal tube. You will have a fantastic low weight tank that will last for years.
https://www.ebay.com/itm/IK-Solid-Rubber-Stopper-Bung-Laboratory-Engine-Push-In-Sealing-Plug-15-Size-Tid/253319600073?hash=item3afb0657c9m9QZUitXgPBjuWwK5h0HwLg:rk:20

Perfect 1/2A size pressure fittings for .020 to .074
Or dig through your stash to see if you have something small enough.
https://www.ebay.com/itm/CLIPPARD-11750-02-3-56-to-1-16-I-D-BRASS-HOSE-FITTING-PKG-OF-10/272405170975?hash=item3f6c9d0b1f:g:EYUAAOSwNRdX-BM6:rk:70

3-56 x 1/16 ID
Approx 2.5M thread x 1.5M ID


Once you make your first small nitro tank you will be proud of your effort and sad to see it buried
out of sight in the wing. Note I have the heat shrink clear overlap over that ring on the bottle yours
would fare well if you leave a few threads left on the neck of the bottle for the heat shrink to grip to.

Thank you Brad, for sharing your hard-won knowledge and for taking the time to go in to such detail and then for finding the links to the parts I need and then posting them.  Way above and beyond and I can't tell you how much I appreciate it. I hope I have the opportunity to follow your example and pass it forward sometime like you have.

Your most welcome Dave others looking in can do the same.

I have finished the all aluminum tank, it's going to be used
with a performance engine for 5 ish min. flights using pressure.
A profile speed plane with the tank completely exposed with
two polished aluminum straps holding it in place. Plane will
be strong enough to handle 180 mph into the wind.

A portion of the anodizing was taken off the lip of the lid so only the front face is left red.
The brass was polished and ID was recovered after using a tubing cutter. I haven't checked
yet but capacity should be more, around 1.85oz filled to the brim 55cc



The .09 has benched well with a pressure tap, needs to be tested with a header / tuned pipe next.
I have a Uctkam 1.5cc tuned pipe just for this engine, the pipe has been tested with the more heavy AP .09.
With the results of the scary TD .05 on pipe I expect the .09 will be quite the screamer!
The mighty TD .09 has taken the DART to 144 mph open exhaust, with a tuned pipe 160 +mph is possible 5.25 x 6.5
Shown here with a beautiful radial mount / all aluminum case, a CNC header will make this a most serious performer.  

Last effort was to do a leak check, verify the over fill tube is at the top of the tank and
capacity check shown here the quantity it held was put into a Du-bro tank for reference.
Also full tank weight was checked.

Great work Brad. I see you added a pressure tap to the stock COX muffler..how does it work with the black slide ring also added? Do you then shim the cylinder to non-SPI?

As you can imagine in the field this can be open as far as you wish making the SPI function breathable enough.
The exhaust window was opened up just a bit as shown in the pic for the test. It should do even better wide open.

url=https://servimg.com/view/18577711/1604][/url]

I have modified my stock muffler, put a pressure tap in place of that useless power robbing
exhaust header. Big improvement with a peaked NV to sing mode good and steady. Pic shows
how much I had the window open for the exhaust, the pressure tap really woke this one up.
The pressure is only there when at full throttle so the idle is really good no flooding idle can
go way down with no issues. Nearly 2lbs of thrust strong HP/W output!

6.25x3.5NN Combat prop:
Static 20,914 rpm / 30.7oz thrust / 1.9lbs / .326hp / 243w / 64 mph pitch speed.
What would be the next move is ask Greg scale up a CNC header for this engine and try it with
a 1.5cc tuned pipe. I have a Utckam on the ready if it happens. Need to do the testing on the CNC
header TD .05 yet, hopefully soon, seen a preliminary milled unit it looked fantastic, low weight not bulky.

Thanks I also find the 09 with its large dia and unscreened venturi does not draw fuel really well but because I use balloon tank a pressure tap does not make much sense. I place the tank instead as near and high as the fuselage structure allows.

Boy, you guys' dedication is amazing. I'm slightly humbled as a bolt 'em and go kind of hobbyist. Back in the days when I felt better and wasn't yet committed to CLPA, I had started tinkering, but never quite aspired to reach this level of performance. I do have a Q40 Pylon racing friend and he's a lot like y'all with the bigger power plants. These are amazing machines. Thanks for sharing all this cool stuff. I need to re-read some of it, as I just woke up from snoozing in front of my computer, Lol. I do that with my YouTube watch list too.

Carry on having fun,
Rusty

balogh wrote:Thanks I also find the 09 with its large dia and unscreened venturi does not draw fuel really well but because I use balloon tank a pressure tap does not make much sense. I place the tank instead as near and high as the fuselage structure allows.

Andras, have you ever tried a double balloon? The fuel is in the inner balloon, and pressure is applied to the outer balloon. I honestly can't remember if I actually heard about that or if I just made it up.
Rusty

Thanks Rusty that is also a good idea. It needs the outer balloon to be just a bit larger than the inner one so that the pressurization should start right after the engine is atarted. It practically means identical balloons one pulled into the other. The lead out of pressurization tube from the outer in a gas-tight way needs to be thought over.

You could also place the balloon inside a regular hardwalled tank, and mimic the Tettra Bubbless tanks.

Thanks Kris good idea I will check what hard wall tanks will fit in the nose as this is an issue with my smaller planes like the TeeDeeVooDoo that carries 1oz in a balloon tank good for a 4-5 minutes flight. I assume a 1.5oz hard wall will accommodate the 1oz balloon with some allowance for imperfect match of their contours.

I wanted to update this thread from the original 1st post as a follow up. There will be some
more updates in the spring from the chapters of scary stuff to include .020 flights.



Nano X Cox TD .051 3rd Flight Tuned Pipe APC 4.3 x 5.5N Speed Plane
Last two passes are the best peak: 28,181 rpm / 147mph PS / 143mph doppler pass
Now the fastest TD .051 3ch plane on You Tube - bested Nano III now in 2nd
Best static 21,962 rpm / 7.1oz thrust / 115 mph pitch speed / Pipe at MRP 7.5"
.144 hp - 107.4w / 7.1 oz thrust / stock piston /cylinder and crank!
25" span 75 sq. in. wing / 8.2oz RTF / Temp 87F. dry, winds 7 - 12 mph.
25% nitro / 20% oil / SPI engine / no pressure tap.
Kamtechnik turbo plug adapter & prototype manifold / header O.S. RP 7 turbo plug.
No mods to cylinder, piston or crank. Only add odd aftermarket parts and
no high nitro just off the shelf 1/2A Fitz fuel!

Great flight Brad though I must admit I rather heard than saw it..  I often hear in your vids that commercial airplanes fly over you at low altitude...I guess you and I are similarly "covert" pilots in our fields.

Man! That thing is quick!

Thank you Gents,

It is best viewed on as much monitor or TV as possible. That field is over 250 yards from end to end.
the plane needs the room making a Cox powered plane a real heart thumper to fly. I have a new
modified APC carbon prop to test this spring: 4.5 x 6.25N / Narrow tips still good thrust yet keeps
the rpm up est. unloaded to 27.7k / 164 mph pitch speed. Lower prop weight and thinner airfoil
with narrow tips allows the engine to keep the rpm within pipe function. Squeaking out another
16 mph PS is nearing what APC can offer to test. There is a 6.5P that can be tried / 171PS might
be possible with enough prop mod. Will require a new plane to go any faster. Note the big bite is
at the hub keeps the bulk of the torque stress near the crank the rest is to guide what's been bit
smoothly with function for best possible thrust provided by the given cord and length. Note the
minimal low weight bullet spinner provided by Ron Valentine just enough for elect. start. Fits down
in the inset of the prop perfect to keep the mass close to the thrust plate.