Len, Brett, Ted? 100 questions...

I'm really exited about the pipe business, the few guys here in Brazil that use PA's and pipes got them already set by Randy, it's kinda "plug and play".

I had to figure my setup on my own (with a little help, no, a BIG help from my friends Len and Brett.

I was told to put a copper ring at the end of the pipe and fix it there with JB Weld. No JB Weld in Brazil, so I got some thin wire (the kind you use to wrap lines and leadouts), rolled it aroun the end of the pipe and used epoxy. The epoxy takes well the heat.

I sanded the header and the exaust with 600 sandpaper, put them together with a silicone glue. No leaks.

Rough sanded the header so the silicone yube grabs on it. Why not put a "grab ring" on the header too, like on the pipe?

It now gets the "tune" at 12,000 rpm.

If I want less revs I'll need a longer silicone tube. Is it OK to have about 1.5" distance between the pipe and the header?

I read Ted talking about 4-2-2 break on a piped engine. I didn't know you could run a piped engine on a 4-2-4. Ted?

I'm using 25% oil (20% synth/5%castor) and 10% nitro. Len said something about more nitro on hot days, less on cold days.

What is the minimum exaust timing you need to pipe an engine? The CB.46 seems to have 120 degrees, 125 at the most. Would I have to give it more exaust timing? (No fear of spoiling the sleeve, Daniel (the maker) is willing to support any experiments, if I mess it he gets me a new one. The real cost is the fuel to break it in, it takes a gallon of fuel )

Does a pipe need any cleaning? I mean, wash out some of the oil that stays inside it?

Thankful in advance,

In Christ,

>It now gets the "tune" at 12,000 rpm.
>
>If I want less revs I'll need a longer silicone tube. Is it
>OK to have about 1.5" distance between the pipe and the
>header?

That's fine. You should have some space there anyway which helps to keep the pipe cool. Some will put a small piece of the pipe back in the gap, but a short distance of tubing alone is fine.

>I read Ted talking about 4-2-2 break on a piped engine. I
>didn't know you could run a piped engine on a 4-2-4. Ted?

It depends on the engine. If the engine will run that way without a pipe (PA, for instance) it can be set up to run that way on the pipe.

>I'm using 25% oil (20% synth/5%castor) and 10% nitro. Len
>said something about more nitro on hot days, less on cold
>days.

Yes. Also, you can use it to compensate for higher altitude. However, you should set up for where you live for "normal" temperatures. If you need more "kick", raise the compression (slightly) or raise the nitro, or go to a slightly larger venturi. But the change in nitro can be used when the temperature varies through the day.

>What is the minimum exaust timing you need to pipe an
>engine? The CB.46 seems to have 120 degrees, 125 at the
>most. Would I have to give it more exaust timing? (No fear
>of spoiling the sleeve, Daniel (the maker) is willing to
>support any experiments. Exhaust timing is used to determine pipe length. If the engine will run well without a pipe, it can be made to run well with a pipe. You don't need to change the timing just because you are on a pipe. But you do need to change the pipe length if the timing is different.

>Does a pipe need any cleaning? I mean, wash out some of the
>oil that stays inside it?

>Ion

Yes. The oil will generally run out (like onto the carpet). The biggest problem is baked on castor and you can find that the inside, especially at the inlet, can become restricted by the carbon as this is where the exhaust returns just as the piston closes the exhaust of the engine. You may need to clean the header and the inlet of the pipe on occasion. A lot depends on how you run it.

Len,

can't I put a device on the header similar to the one on the pipe to give some "grab on the silicone tube?

Would epoxy take the heat on the header?

That would allow me to make the plug-baffle distance a little longer, in case I want to run at 10,000 rpm, for example.

Mike Starrett raised his scheurle ports a little.

Would that be in order to allow it to do a better "break" (Randy said there's no need to do any mods on it)?

>Len,
>
>can't I put a device on the header similar to the one on the
>pipe to give some "grab on the silicone tube?
>
>Would epoxy take the heat on the header?
>
>That would allow me to make the plug-baffle distance a
>little longer, in case I want to run at 10,000 rpm, for
>example.
>
>Mike Starrett raised his scheurle ports a little.
>
>Would that be in order to allow it to do a better "break"
>(Randy said there's no need to do any mods on it)?
>
>Ion

There are many roads that lead to Rome. (The Roman Empire once boasted that "all roads lead to Rome", but that was only because they built them.) You can change the porting to change the characteristics of the engine, but it is all a matter of what you want it to do. Raising the boost port only is not going to allow it to do a better break, although there are some who want to raise it to match all of the rest of the ports. I would be of the opinion to leave it alone when used with a pipe. The pipe will regulate it when set correctly. And if you are looking for a little different run characteristic and think you need to change the porting, this is not something to do yourself unless you are prepared to ruin a couple of engines for which parts are no longer available.

On the header question, I don't know why you are needing "grab" on the silicone tube. If you have the right size tubing it is going to grab all by itself and will be a bear to move anyway. You could almost put it on without using the ties (not advisable) but with the ties that tubing is not going anywhere, even on the header.

One thing, do not shorten the header. If you need to shorten anything, always shorten the pipe. If you shorten the header, you run the risk of cooking the pipe.

>I'm really exited about the pipe business, the few guys here
>in Brazil that use PA's and pipes got them already set by
>Randy, it's kinda "plug and play".
>
>I had to figure my setup on my own (with a little help, no,
>a BIG help from my friends Len and Brett.
>
>I was told to put a copper ring at the end of the pipe and
>fix it there with JB Weld. No JB Weld in Brazil, so I got
>some thin wire (the kind you use to wrap lines and
>leadouts), rolled it aroun the end of the pipe and used
>epoxy. The epoxy takes well the heat.
>
>I sanded the header and the exaust with 600 sandpaper, put
>them together with a silicone glue. No leaks.
>
>Rough sanded the header so the silicone yube grabs on it.
>Why not put a "grab ring" on the header too, like on the
>pipe?

You could if you want. I get good enough results by using 100 grit sandpaper around the end of the header, and then cleaning the header and rubber tube with lacquer thinner. Once it runs a few times, you could probably go without the tie-wraps.

Of course, if you were really ambitious, you could make a tool to bend a flange on the end of the header.

>
>It now gets the "tune" at 12,000 rpm.
>
>If I want less revs I'll need a longer silicone tube. Is it
>OK to have about 1.5" distance between the pipe and the
>header?

Sure. If you don't like the unsupported rubber tube, you can just get a piece of cut-off header and push it up inside, leaving enough for the tube to still attach.

>I read Ted talking about 4-2-2 break on a piped engine. I
>didn't know you could run a piped engine on a 4-2-4. Ted?

You can run a 4-2 break on *ANY* 2-stroke glow engine - ANY! The notion that there is some magic potion that makes this happen is just so much FUD. The *speed* and *load* conditions at which it occurs for any particular engine of course varies wildly, and what most people talk about as a "4-2" break motor is a motor at which the 4-2 break occurs with loads and at speeds that are conducive to good stunt performance.

Most piped engines today run on either side of the break point in flight. Indeed, one of the most important feature in setting up the engine is to control the effects of the break, which tend to be pretty dramatic in some cases. More dramatic, in fact, than most "4-2 break motors". A Fox clicks back and forth with an impressive change in the sound, but an extremely mild change in power. Some piped engines, depending on how you set them up, have almost negligible change in the sound but pretty impressive change in the power.

Additionally, you don't have to go from 4 to 2 and back to get a power change. Indeed, the 40VF, which I ran in a constant 2-sroke, sounded pretty much the same all the time. But the pipe regulation was pretty strong, and you could easily feel a power change when it needed it. Same thing with my PA61- it runs in a constant 4-stroke, but the power it not constant at all. Some people refer to a constant 4 of a constant 2 as a "constant speed run". but it's usually not. They're getting fooled by the noise it makes.

Controlling all of these factors to your benefit is why we spend more time talking about engines and props than just about anything else. There's a lot of factors to juggle, and a huge range over which it will come at least work, if not be optimal. One of the nice things about piped engines is that they have so much reserve power and range of operation that you can almost always get it to work well enough. And, you can change it how you want. You sure couldn't do that (or at least to nearly as great an extent) back in the so-called "good old days"!

I would also note that people tend to get in "ruts" where they simply ignore what the engine is actually doing, or capable of doing, in an effort to fit it into a defined category. I prefer the path of least resistance - run the engine the way *it* wants to run, and see if it can work for stunt.

In short, a lot of the talk you hear about 4-2 break, "constant speed run", 'piped run" tend toward the hooey end of the scale.

>I'm using 25% oil (20% synth/5%castor) and 10% nitro. Len
>said something about more nitro on hot days, less on cold
>days.

That's probably OK, but don't go overboard on the oil. This is no Fox or McCoy - it probably likes a little castor, but it's definitely not necessary to keep the cylinder alive. Too much oil just binds the engine up and loses power.

>What is the minimum exaust timing you need to pipe an
>engine? The CB.46 seems to have 120 degrees, 125 at the
>most. Would I have to give it more exaust timing? (No fear
>of spoiling the sleeve, Daniel (the maker) is willing to
>support any experiments, if I mess it he gets me a new one.
>The real cost is the fuel to break it in, it takes a gallon
>of fuel )

It can work - but the pipe will be proprtionally short for a given RPM. If the exhaust only stays open for 120 degrees, the sound wave has less time to shoot out to the baffle (or second baffle, or tail cone) and come back. Short exhaust duration = short pipe, long exhaust duration = long pipe. That's why you will need pretty long pipes on the 25VF - I bet the exhaust duration is probably 145 degrees.

Whether this wil be useful or beneficial on this engine is something you will have to discover for yourself. I

>
>Does a pipe need any cleaning? I mean, wash out some of the
>oil that stays inside it?
>

I occasionally clean mine, but only to keep a castor oil scum out of the bathtub when I pressure-check it. I doubt it's necessary for maintainence.