BME 58 - what airframe and what exhaust?

[RCAddiction]

Guys, I recently purchased a 58 Extreme from Tom at BME after lusting after it for some time. Now comes the part where I figure out which airframe to use to carry the engine around. The plane needs to be quiet for my field so a canister or quiet pipe is in order. For the 58 Extreme, BME recommends these very large canisters and pipes.

Pipes:
MTW RE3
KS1090
ES Composite (BME not recommending this any longer...they find it to be causing some engines to run hot)

Cans:
MTW TD110, TD105K
KS95

These are really large. Tom feels the engine requires similar exhaust volume as a 80-85cc engine due to timing and lots of airflow. I'm struggling to find many 50cc airframes that can accomodate these large exhausts. I did review the BME 58 exhaust thread, but it really didn't answer my question.

Questions
Do you feel the BME 58 uniquely needs such a large volume exhaust? If so, what airframes are you flying and/or recommend to accommodate the large exhaust? What pipes or canisters are you running? Input from actual BME 58 Extreme owners would be best, if possible. thanks!!

[Altavillan]

RTK's internet has been on the fritz lately so I'll report what he's running now. He tried the ES pipe but I don't think he ever felt comfortable with it's tune regardless of what length he tried. Now he is running a Mac's double quiet pipe. I can phone him for header length he's currantly running. He's happy with the way it runs as per our last phone conversation. He hasn't removed the cylinder yet to see how the engine is doing inside with regards to depositing carbon and if there's evidence of back pressure against the exhaust port side of the piston.
My experience around the engine is it's running as a person would expect a tuned pipe to do. A bit hard to really tell by engine sound because the pipe is so quiet all you can hear is the prop. Very much more power than the stock mufflered 50cc engines at my club. Night and day difference.
Far as I know Mac's makes the only Quiet tuned pipe, and if noise is an issue it works great.
I don't run the 58 but I do have 2 115's on my Bud mufflers. One engine is very happy on them, the other I'm not sure yet. Shorter header on the second one might be causing a tad more heat. I'm still testing, it's early yet to do a teardown.
As far as planes go you want a Slick. Because they are new and different. Deitrich or AJ. Have to wait for Deitrich though. I like the huge elevators they put on AJ"s planes.

[RCAddiction]

Thanks, Altavillan. I already have a 50cc 3DHS Extra SHP (Taurus 52), and the Slick seems to be really similar. I'd like something a bit different. Dietrich...yikes....definitely not a fan of the Dietrich schemes. There's a new AW Edge coming. Some new EF stuff in the fall. MX2 at OMP. Frankly, if I didn't have to worry about a jumbo can or pipe, there are quite a few good choices. Wildhare says his Edge or Extra can handle the MTW 105K.

I saw Ralph's postings on the Mac's double-quiet pipe and was curious about it. I'd had great success with the Macs quiet pipe on my YS120 some time back. So quiet I couldn't hear when it dead-sticked! The DQ pipes listed in the marine section (where they show the DQ pipe) seem to be for much smaller engines. Is this something that is not on their site? Does he use a Macs header or one from Karl?

[CSpaced]

You should check out PAU's 30% Sukhoi 26, its a perfect sized plane for that engine and is cannister ready.
http://www.flypau.com/html/sukhoi/sukhoi.html

[Altavillan]

He has 60cc pipes as long as he can get the tube. Last I looked he had it available. I think you have to order the double quiet pipe made special. I'm not an expert on tuned pipes. I'm getting much better with them though. I have a Mac's for my 3W 56iB2. Before switching over to the Bud canns I had it dialed in very well. It takes a long time to learn them on your own. Eventualy you realise you can't set it for max power at WOT while holding the plane on the ground. But find a spot where everything works just right. As soon as the plane is off the ground and the prop unloads you loose the tune cause it's running past the set peak. So full tuned pipes don't really fit the need, unless you are racing. The quiet pipe can help the engine breath easier, run cooler, and make more power. It just takes time to find the length.
http://www.macspro.com/tunedpipes.asp

[RCAddiction]

Yup, I found the 60cc pipe is available, and they special order the DQ version. Cool stuff. About the same dimensions as the MTW RE2...wonder which is quieter. Concerned that the Macs may still be finicky as far as length and a bit peaky. Perhaps I might just go with a canister.

[Altavillan]

As soon as you put it on a header you will have the same issues with tuning it. The cannister is a smart way to go. Same basic power boost effects when tuned correctly and lots cheaper.

[Tired Old Man]

Don't go with an ES pipe on the 58. Poor RTK beat his head and his piston against the wall with that one.

[RCAddiction]

Tired Old Man, what type of exhaust do you suggest? In your opinion, will this engine do fine with a normal 50-65cc canister?

Goal - I am not trying to extract every last rpm from the motor. The priorities are quiet and reliable with good power.

[JEFFRO503]

hey lee , i ran the 58 with a 13.5" header and an MTW 75K and was getting some impressive numbers with it. And after a few gallons , when the motors started to break in , it was a great combo. Also....you may want to check into the JMB cans over at "troy built". They are supposed to be able to run on just about any 50-60cc motor and do very well.

Oh yeah , my vote would be for a 3DHS AJ Slick as well. I think in the 50cc sized class , i don't think there is a better bird out there , and it's friggin' huge! I haven't had the time to finish mine yet , but it'll get the BME 58 and stock muffler put onto that one. I'm actually ordering up two more , which will be electric. Going "Neu" power on those.

[RCAddiction]

Jeffro, did you have to play very much with the header length to arrive at 13.5", or perhaps that length just worked well to fit in your aircraft?

I have a JMB 60/60/270 that's in the same size range as the MTW 75K and could certainly use it.

[Altavillan]

You cannister has a section of pipe going into it. Measure that and add it to your header length. You'll want around 17-18". Play with fine tuning from there, be cautious going shorter, watch for heat fade in up lines. Correctly tuned you will have slightly lower static rpm but real good in air top rpm. If your tune is correct at in air high throttle settings the engine breaths easier leading to cooler mid/max power running.

[branwell]

I have the ES-55Gs on a BME 116 in a 110 Yak. Its a great great combination.
The motor is super powerful and does not get hot. In fact, it only runs 20 degrees hotter than my other Yak which has a DA-100L and KS-1060 pipes.

Heres the key with ES pipes. LONG LONG headers.

I also have the RE2 and KS 1060's.
The RE2 has the center point of its convergent cone 20.25" down the pipe.
The KS has it 21" down the pipe.

Guess where it is in the ES? 17.75.

What does this mean?
It means you need to run a 3.25" longer header on the ES vs the KS for the same tuning RPM start point.

Additionally, the BME has an exhaust timing of 168 degrees which requires a header 4" ( ish ) longer than a motor like the DA100 which has a timing of 150 degrees.

And this is where I think people get into trouble.

Info on header lengths for the BME is hard to come by, and compared to pipes like the RE2's or KS, the ES pipes are virtually unheard of.

If you are setting up for the first time, where are you going to get info on header lengths?
Tom at BME doesn't really know, he hasn't tried them himself, and ED at ES doesn't know either.

So what do you do if you know nothing about pipes?
You look at what others are doing on their motors, and if you look at what people are doing on motors like the DA100 with aluminum pipes, you might think headers in the 11 to 12 range will be a good place to begin tuning ( that is what Ed at ES was recommending last I spoke to him ).

When I started, the closest I got to what others where doing was 13.25", and that just about slagged my motor.

I ended learning a little about tuning theory, applied what I learned to get a start point, and then tuned in the air.

I ended up with 18" headers for the BME 116 / ES combination and it works great. No heat issues, no midrange problems, no melted pipes. Just lots of power and low noise, without the excessive weight of the aluminum pipes.

In my opinion, the ES-55G would be great on the BME 58.
If you are looking at about 7300 RPM static, I think a good start point would be 14.5".

By the way, I emailed a bunch with RTK, he was running 13.5 inch headers. Said he would have to modify his plane to make them longer, so he didn't.


Branwell

[RCAddiction]

Branwell, those are all excellent points. Thank you. The problems you state with getting good BME info are true. Yes, Tom at BME is a very, very good guy but he really does not yet know what exhausts to run...he asked his son for me (I think it was his son)...but not sure if his info is all that accurate.

He told me 17-19" with an RE3 and 12" or maybe a little longer with a KS1090. That sounds wrong.

Question
Would the additional 4" (due to timing) apply to the use of a header for a canister, like the JMB?

In other words, if I measure the interior pipe length, add the header, and compare that to what DA50's use, can I add 4" and get a reasonable starting point? Jeffro is happy with his 13.5" header on a MTW 75K. Don't know if that's reasonable with a JMB 60/60/270.

Note:
KrazyC has the ES pipe on his 58 (he lives not too far away) in a Yak and is happy with it. However, I don't believe he's had time to put a ton of flights on it yet. The lazy way for me would be to copy his setup, but I don't know if a long pipe will fit in the planes I'm considering. Your setup (cool photo, BTW) looks LOOOOOOONNNNNNG.

[branwell]

Hi Lee,

I think there must be miss communications somewhere.

17" to 19" sounds very much like the length needed for the 116 on ES pipes.
Given that most people run the 58 at higher Rs than the 116, it would run a shorter header. I think 14.5 would be a good place to start.

The RE2 needs a 2.5" shorter header than the ES for the same RPM, so if 14.5" is a good starting point for the ES on the 58, 12" would be a good start point for the RE2.

The RE3? I don't know its internal dimensions so really cant say, but if you can get me the measurement from the pipe inlet to halfway down the convergent cone, I can calculate a start point for you.

As to cans and tune pipes and header length equivalents. I really don't know if they are the same. I do know header length does effect cans, I just don't have enough experience with cans to offer useful advice.

Note: Tune pipes need headers tuned to specific RPMS, and have a very specific power band depending on the pipe design. Things like prop choices, airframe, and flying style play massively into your final choice of header length.
If you fly predominantly IMAC or Pattern, you will very likely end up with shorter headers than if you split your flight with 3D.
If you fly a light plane, you will end up using shorter headers.
If your plan is very draggy, you might end up with longer headers.

Point here is if you are planning on copying someone's setup, make sure all your stuff is the same, including your flying style and altitude.

This makes it sound like tuning is hard. It really isn't. You just need to dedicate a good flying day to it.
One way is to get a long coupler, say 4", and run shorter headers. You can then slide the coupler along the header to change the total system length. Run the motor, tweak the needles, get an RPM and temp reading. If its good, fly it and see what you think.

If the mid is garbage but its got a heck of a strong top end, the length is likely too short.
If the motor doesn't unwind much at all, it likely too long.

Land, adjust, fly. Pretty soon you will get a feel for the system and the differences the lengths make.

You should be able to find a place where the mid is as good as with mufflers, but you are getting a nice boost in power.

The whole thing about pipes being "pipy" is not really accurate for the pipes we are discussing. All of them have smooth midranges if the headers are set correctly.

Once you do find the sweet spot, get an extension ( Desert and AI sell them ), and get a stainless brazing rod ( AI sell them ). You can then take your MAPP torch and braze the extensions on. I am a functional retard and I can do it, so so can you

Branwell