Cox .01 /.02 /.05 /.09 /.15 Speed Planes

Parts came in to set up some goo control (1g very light) and perfect fit they do not
rotate. Will do a bench test when ready. These are perfect. One has a channel to
allow exhaust out of both ports one has no channel converting it to a pure single exhaust.
There is enough meat on the top side to but a pressure tap. O ring seal for the top side and
variance and seats over the crank case ring at the bottom for a drip free fit.

Greg has done a fantastic job of getting this right from the start. Both have max exhaust breathing
for their type. 2nd to last pic shows the exposed cylinder last shows how it seats over the cylinder
footing on the crank case. Oil was used on all mating surfaces and the O ring to help the seal.

Ok made up the engine config without a pressure tap for now will test
as shown with a HQ prop see how the carb does with some back pressure
from the manifold. Of course this would do very well with the stock venturi.

Thank you Mauricio!  
Yes mentioned the RC carb today to Greg again, would make a real nice package deal hop up kit for TD .020

What mods are possible here is a short list of ideas:
- Turbo Head
- Backplate
- Standard Manifold / Header
- Performance Header with optional tube interface adapter
- Optional 1/4th wave bolt on tuned pipe
- RC carb integrated to the stock NV / body
- Performance crank case with ceramic bearings for thrust or rpm
- Speed bullet spinners with stud bolt
- Deluxe full carburetor with low end / high speed needles
- Aluminum performance cylinder with secret sauce ported sleeve for stock or turbo plug heads
- Performance Nelson plug version for modified performance secret sauce cylinder
- ABC retro fit sleeve with aluminum piston
- Full wave tuned pipe for max torque.
- Radial mount performance crank case
- Alien performance crank big intake, flow enhanced
- Dino Breath Diesel Head conversion - used with performance crank / piston upgrade.

   

Yes was having some fun with the list of course but some of the idea's are viable.

Truly a throttle, manifold/header, backplate, and turbo plug will really make for a
very nice TD RC .020, many of our favorite planes could perform very well with
the setup will make a perfect park flying power package.

First test of the manifold and header:
Prop has no back cut just clipped at the tips / see prop per last engine pics
HQ 3.7 x 4.5 / 20,833 / 3.3oz thrust / 89 mph / .054hp / 40w

Engine ran steady once on the needle, started rich and feathered in the rpm.
The fuselage and left wing was bone dry only the outer portion of the right wing
saw any oil spray no engine drip, it was a wonderful clean run. See the vid
below and notice no oil build up on the plane. I zoom in at the end of the vid,
right behind the engine where the goo typically really builds up bad nothing there!!!

Will bench test this configuration next with the other manifold. This one
has no inside groove to allow breathing from the opposing exhaust port.
Effectively it is a single exhaust engine in this state, this particular
cylinder lines the engine up as a rear exhaust FIRE engine. Front Intake
Rear Exhaust the preferred layout of race engines for optimum gas vapor
flow performance.

So far the other manifold has proven to breath very well with no apparent
loss in power calc to 40w. Note the header is wider than the cylinder port to
provide best possible breathing. This engine could be mounted inverted or
side ways or canted to control the oil spray direction.

Will test with a 3.3x4.5 prop shown, venturi is stock bore / Cox FIRE engine for max rpm.

Published on Apr 19, 2018

Cox Tee Dee .020 FIRE speed engine (Front Intake Rear Exhaust)
Testing new manifold and header design for pure single exhaust
performance where the front exhaust port is completely block off.
Results:
Peak: 3.3x4.5 / 23,175 rpm / 99 mph /.047hp / 35.1w / 3oz thrust
25% nitro / 20% castor


The engine was thirsty I had to turn out the NV quite a bit to keep up with the fuel demand.
So next test will be with a pressure tap on the header should help to turn in the NV and stablize
the top end demand. The design had a purpose made thicker top on the header just for a thread tap.
With the particular tank and line the engine required 6.5 turns out to run with no pressure so
hope to reel it in to about 3.5 to 4 turns.

Tested the thirsty single port FIRE speed set up with a pressure tap busted 100 mph static!
Not bad for a 4.5P prop. RPM picked up past 24k then settled in 242 rpm more than without
the tap, was able to set the NV at 4.7 turns. I need to make a small 1/2oz fuel tank for bench
testing the TD .020 will optimize fuel draw. The one used for testing is not ideal.




Will be test flying the type 1 with the groove first with no pressure tap this weekend if weather allows.

Without the pressure tap 6.5 turns out on the NV
With pressure tap 4.7 turns out on the NV (indicates more pressure flow to the NV)

The blast of of oil going out compresses any air volume in the header section forcing
air into the tank. If the header was longer it would create more pressure to the tank.
Mufflers and tuned pipes have a sweet spot where pressure is more continuous the
header is what I have to work with.

Because the header is short and has a larger ID than the exhaust port see pic.

Think of a aluminum cased single exhaust engine with SPI has no problem functioning.  
With a sleeve and then the aluminum case there is reasonable distance to the mouth of
the exhaust from piston wall.

Oil spray is controlled with minimal hindrance as possible, this is a test manifold for tuned pipes
1/4 - 1/2 to full wave pipes.

The first manifold tested has a groove so both ports breath that one is for general flying.
There will be a second version with bolt on muffler I will do bench and field testing on it too.
I am making sure no other tweaks are needed prior to moving forward.

In the end you will have multiple options to choose from. Another option has a bolt on adapter
to convert to a round exhaust for using silicon tube deflectors for max goo control direction
or tight in cowl setups. Some vintage designs you may want a long tail pipe past the wings with
little concern for screaming power just easy lazy day sport flying with no oil spraying on your
covering type. How about dual headers for each port with twin pipe exhausts for scale
planes/ war birds? This can expound to the other displacements .049 / .09 / .15 potential.
Nice thing with these engines the projects can be many and cheap to do compared to larger
plane projects requiring dedicated flying fields.

When ready there will be world wide availability for those who wish to have performance
aftermarket manifolds and header type configurations. You will have various exhaust systems
to choose from that best suit your needs. From flying models to static display collections there
will be some most excellent opportunities.

I will be sharing the testing phase of various parts, these are wonderful add on's for many who
enjoy micro engines and had always wished for better precision parts after all it is 2018.
It will be a bit of a tease to show and tell but like the backplates sizes turn around time for mass
production / availability was quick considering.

Here shows the SPI gap of this particular engine

Here shows the piston in the down position

Thank you Crankbndr look forward to pushing progress, innovation
and encourage use with existing / new projects.

Looking at some possibilities with .020 pipes. Combat engines are using short 1/4 wave bulb type pipes to
for a peaky pipe run max rpm. For me the .020 need torque the full wave pipe would be best. A good
compromise would be a half wave pipe. 1/2 wave is popular with high performance speed outrigger hydro's.
My 1/2A riggers run on full wave pipes as I need the torque at launch the popular .12 to .21 class riggers
can get away with 1/2 wave pipes plenty of torque at launch. Putting that tech to work with a TD .020
one could bet by with a 1/2 wave pipe for a bit more top end rpm and to save weight and drag.
Profi .8cc pipe was used to scale for .35cc engines it is a very good pipe design, I have 6 of these.
2 on riggers and 2 on planes at the moment. Can just add K&S tubing to run full wave more torque for
the 4.5x2 and the 4x2.5 stock prop. Mean reflection point set for 24k unloaded. For me I want to run speed
props at 32.5 to 34k rpm. MRP for the full wave is 8.5" center of piston top to distance shown on pipe diagram.
- 1640(wave speed) x 150(timing) ÷ 7.5 (MRP pipe length) = 32.8k rpm
Stock 4x2.5 prop 10" MRP / 24.6k rpm with a 1/2 wave pipe you can get by with 5" MRP

Balogh thank you for the Greenie!!



Cox TD .050 / Profi Tuned Pipe / 25,193 Static - HQ Prop 4 x 4.5
Static 7.3 oz thrust / .132 hp / 99w / 107.3 mph /
9.3in MRP / 140 deg timing / Pipe set for 25,215 rpm
Non SPI / 20% oil / 30% nitro. For bench testing you use a smaller
prop to simulate in flight unloaded rpm.

The above test was surprising as 140 deg timing is not much to work with.
With a fine file you can improve the gate time by removing a bit more material
from the outer face of the cylinder top of the exhaust port at a angle with a 1/2mm
from the actual opening only on the header side as the other port is blocked off.  
Many performance engines use SPI and tuned pipes I would prefer to select a cylinder
that has the least or no SPI. Running the .8cc pipe makes a unique sound at the flying
field it is much more enjoyable to the ears than open exhaust.
All engines may vary some:
TD .049 / 140
TD .010 / 150
TD .020/ 150
Norvel AME .06 / 150
AP  .06 / 160

Hi Greg, the manifold header with the groove is a great first step to simple oil control
with some sound suppression for the masses. Great for the Pee Wee and TD .020
Same can be provided for the .049 engines  

A manifold with bolt on muffler would mimic the Cox RC .050 and .09 version for further
sound suppression and oil control. The .020 needs a simple RC carb to complement the setup.

The bolt on muffler type header/manifold could use a bolt on adapter for round exhaust
to use with silicon tube as a exhaust diverter for in cowl projects or just a way to shoot the oil straight down.

The pure single exhaust manifold version with a tuned pipe and the above adapter
will be a awesome add on, some real fun for folks to try out a project with a pipe
without breaking the bank / able to fly in small spaces. Looks and sounds cool.

Today will head out to the field and flight test the manifold will post a vid.
Getting these add on's on vid showing their function and benefits will help generate
interest.

I am more interested in pipes and will be happy to absorb the cost of them in limited production.
The main interest would be most likely mufflers and header manifolds. Some drilled for bolts some not.
Small runs of these would be best to test the waters. With a dedicated web site you could list the options
and fill the orders based on availability #count till your ready to run another batch. Word of mouth and
field use will help along with postings on line.

To expound on the muffler and for cylinders that line up with side ports more so then rearward
The muffler could be bolt on like the stock Cox RC mufflers a simple tube with a lip would allow
tuned pipes rather than a FIRE configuration it would then be FISE engine.
Lil 1/4 wave pipes like these make a unique sound AKA the Lil Pumper or Lil Spitter.
The design will help pull fuel/air through the carb producing boost.