Zenoah Glow fuel eng?

[Mark Grannis]

DW, very interesting project. Congratulations, on having such an inventive mind!

 

[dwilfong]

DW, very interesting project. Congratulations, on having such an inventive mind!

Thanks mark......I like to think out side the box.........
The fun part is sharing what I do with others.

 

[dwilfong]

Time to whittle me a pipe.
It will be around 2.6 at the belly ID.
This is a 3"x12" piece of wax will see if it is long enough to make the center section in one piece.
Then add the header section and stinger on with tubing.

 

[SayMikey]

Pick it up David im on the edge of my seat waiting on this bas**** to fire off. Almost out of popcorn and I have to pee

 

[dwilfong]

Pick it up David im on the edge of my seat waiting on this bas**** to fire off. Almost out of popcorn and I have to pee

Well it will be 3 weeks till I get my hands on the resin to lay up the pipe.
Thy only make it to order and he is going on vacation.
I can do all the cutting and prep work for the lay up.
Also have to whittle a header out of some round stock.
Soon as I nail down the pipe build prep I will start on the header.
So go pee and pick up some more corn you are going to need it.........................LOL

 

[Wasted wages]

Hard to comprehend how big the motor is going to be, until you see the parts next to the items on the bench... it's gonna be BIG..
and considering the size of the motor, the pipe is going to be big too, I can't help but wonder what the final weight of everything will be and how that is going to affect speed ..

any guess on the final weight of everything ?

 

[dwilfong]

here is the pipe design program

Hard to comprehend how big the motor is going to be, until you see the parts next to the items on the bench... it's gonna be BIG..
and considering the size of the motor, the pipe is going to be big too, I can't help but wonder what the final weight of everything will be and how that is going to affect speed ..

any guess on the final weight of everything ?

No more than a CMB 1.01
Will get some new battery's for my scale and post the weight of both.
I am thinking about 12lbs ready to run less fuel.

 

[dwilfong]

So I have bin playing with the pipe program and found some very interesting thing out.
This is a basic program it only asks for the export area as far as the eng parameters.
Remember all the other stuff with the eng comes down to calculating your port size. So you only need this to figure out the pipe.
First off the diameters of the cones only change when ex port area changes.
So that means that the pipe only gets shorter with ex temp and RPM changes.
The cones get shorter or longer together.
The stinger diameter only changes with ex port area also.
I need more than 12" to make the whole pipe with out the header section or the stinger.
So I have come up with a brain storm........O NO!!!!!!!!!!!!!!!!!
I will make the front part of the pipe including the header strait section and the front cone with a 7 deg angle 4" long and a 1.396 ID out of one piece of aluminum stock.
This will give the pipe a fighting chance to hold up better to the heat and vibration.
Also If I want to make a change I can cut off the CF section and make a new belly and not the whole pipe.
The belly has 2 front cones not including the first 7 deg one I will make out of aluminum. so that is a total of 3 front cones. Then a flat section and one rear cone.
The stinger and front half dose not change much as far as length with RPM and ex temp change and not at all in diameter.
Got the stock on the way so enjoy your pop corn for now.............................................

 

[LohringMiller]

When I tried to build a carbon pipe for gas engines, I used an aluminum header and stinger. The exhaust gas was still too hot for the APC high temp resin. With nitro the EGT should be lower. I know a lot of nitro engine carbon pipes that work well. You are a pioneer for this size, though.

The empirical pipe programs I use also have port area, and temperature as inputs. It also has the horn coefficient, maximum diameter and stinger diameter to header diameter ratios. Horn coefficient describes the shape of the diffuser section. The header diameter depends on port area. I find that a 1.2 horn coefficient and a 3 maximum diameter ratio work well. I finalize the design in a simulation program.

Lohring Miller

 

[dwilfong]

When I tried to build a carbon pipe for gas engines, I used an aluminum header and stinger. The exhaust gas was still too hot for the APC high temp resin. With nitro the EGT should be lower. I know a lot of nitro engine carbon pipes that work well. You are a pioneer for this size, though.

The empirical pipe programs I use also have port area, and temperature as inputs. It also has the horn coefficient, maximum diameter and stinger diameter to header diameter ratios. Horn coefficient describes the shape of the diffuser section. The header diameter depends on port area. I find that a 1.2 horn coefficient and a 3 maximum diameter ratio work well. I finalize the design in a simulation program.

Lohring Miller

Thank you for the input on the cone coefficient and maximum diameter ratio. I was just using what was loaded in there from the beginning but I can change them. I will play with them tonight and see what they do now that I understand what it is.
This may not build the perfect pipe but it will be way better than anything else to try and give this engine set up a good shot at actually working and making decent power. But the engine being as big as it is I don't think I'll have to squeeze every last bit out of all the parts on the engine. Nitro is a very good crutch to make up for certain things if you can actually burn it.

 

[LohringMiller]

The temperature in the program is an important variable. It's pretty arbitrary. I built a series of test pipes that were all too short because I assumed too high a temperature in my program. Industrial gas engines have a lower EGT than racing gas engines. I have no idea what temp you should use, but the often suggested 550C for gas engines is too high. Cut and try is the best way to find out. Build some similar pipes with different temperatures.

Lohring Miller

 

[dwilfong]

Well there is a port to pipe ratio, port to mid ratio, port to out let ratio in this program
also some Ex gas ratios , ratios of specific heat, individual gas content
This is I am guessing how rich or lean it is running and the amount of free air and fuel still left after the burn compared to ex gas.

 

[dwilfong]

Well I got it set up in the lath and did a small test cut.
It cut like a dream.
SUPPER Smooth finish no caking up and makes nice curls as it comes off.
Will put down some plastic to catch it all to use over.
This will be fun to play with I can tell.

 

[dwilfong]

Well I hade some time today and made up the lead in and first cone.
It is 1" inside for the header to slip into and 1.5 long strait.
the cone is 4" long and 7 deg.
Will start on the wax belly next.
The wall is .060 thick and it is much less weight than I thought it would be.

 

[Terry Keeley]

How did you cut the 7* taper? You got a taper attachment for your (Southbend)?

 

[dwilfong]

How did you cut the 7* taper? You got a taper attachment for your (Southbend)?

Used the compound set at 3.5*
It only moves 2.5" so you have to do it in 2 moves. Not to hard after you get the hang of it.
Lots of chatter when the bar is all the way out for the last move on the inside.
I could make it all from aluminum but then that would not be as trick as a hybrid CF pipe.
This will be my last build for some time so pulling out all the cards.
Just got a traier and going on the road for a few years to see the USA.
Got me a hot date with a Golden Trout...........................................

 

[MitchFarabaugh]

If you cut the inside first, it will ring a lot less. Looking good!

 

[dwilfong]

If you cut the inside first, it will ring a lot less. Looking good!

Now you tell me.......LOL
No one will see the inside any way.

 

[Wasted wages]

Can't see it from my house!!

 

[dwilfong]

OK so here it is.
It breaks down like this
1" inlet ID 1.5" long
4" cone at 7*
2.5" cone at 15*
1.25" cone at 25*
1.5" long flat 2.6" diameter
3.5" cone at 35*
Still have to make the .5" ID stinger 3.5" long.
Have to come up with a muffler that is why I did not make the stinger yet.
Still bouncing around some options.