Tomcat_104

My Feedback: (42)

Well, I've been reading what everyone has suggested (thanks by the way) and I'm starting to think that the Extreme 115 is not for me. I'm really not able to "tinker" with a motor due to my disability. I wouldn't mind it and I would gladly be someone's guinea pig but right now this is just not what I want to do. Does anyone have a BME 110 that they could measure? It's not on their website so I need someone to help me out. I need to know how wide it is from plug cap to plug cap. The weight is not important but I would like to know it anyway. A tried and true single cylinder like the Quadra 100M is still a possibility but I would guess the BME twin would have a lot less vibration.

As I named this thread BME Extreme 115...Good....Bad...Need Opinions I VALUE EVERYONE'S opinion greatly. This has been a great thread for me, I have learned a lot. I too hope BME solves the carburetion problem and soon! Until then there are guys here who can help and apparently are willing to help. I don't mind pulling a bunch of lead around but I do want an engine that is reliable, I have far too much invested in the airplane to let it crash! Until they do everone's opinion is needed and respected!

David

altavillan

My Feedback: (1)

Uh... the 110 is basically a 115 with a SDC 80 carb, 5cc larger and more intake ports Most important to you is the capacity of the cooling fins on the BME's to cool an engine in a scale cowl. Keith didn't get overly generous in that department.

RTK

My Feedback: (1)

The 110 is a tad narrower than the 115 and a tad longer. It has the same jugs, but different case and is stroked over the 110.
As altivillan mentioned, baffling is important for cooling, but that is a given for any engine we run.

Tired Old Man

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Thanks. The company is already pressuring for what I want to do next........

altavillan

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I'm thinking Somalia. You have a flair for picking exotic vacation hot spots.

bubbagates

My Feedback: (32)

Just a thought and I'm actually a bit too lazy to go digging but what is the mod Keith is doing?

If you remember back a few years, Brison had a similiar issue that the 115 has and Gary corrected it by installing a little lighter pop-off spring and then stamped an "S" on the side of the carb which corrected the mid range issues that it had. I experienced this between an older blue crankcase version and a newer shiny case. I swapped the carb from the new to the old and the engine really came to life.

Now, I do not own a 115 but have been working with a person I fly with and when we finally got it tuned right it would go rich ever so slightly in a roll. It has one annoying thing I see and that right when it pops on choke it actually tries to start backwards. Then it will take two more flips and it will run in the right direction, just like clockwork. I gotta tell you though, he has it on MTW 110 cans and it turns a 28x10 Pt models prop with autority and it's installed onto a WH 35% Sukhoi at something like 24lbs. Vertical is unbeleivable at full throttle and full is not needed, 1/2 throttle gets you uphill in a hurry anyway

altavillan

My Feedback: (1)

Tap in a pulse port nipple..... Got those
Cut a 1/4" plate out of aluminum to fit on the trusty old chop saw........... there's a few windows in the shop with the origional glass
Drill tap and recess for screws......... Just have to keep it right side up or you wind up with an opposite... witch is handy if you have the snorkel
Drill a couple holes in the diaphram cover for venting..........SDC doesn't need no stinkin tube
Dremel everything that clogs the venturi without any obvious purpose........Your engine isn't broke in yet so you won't have to run dino oil,The grindings will work just fine
Slap it in your plane.............Course I'll be blowing by ya.............But then you'll want that big round cowl to slow ya down for many chances to admire how good lookin your plane is
Let Ralph scratch it real good so you can really fly it.........or do that limbo under the fence you do so well
I'll have you one for xmas

bubbagates

My Feedback: (32)

Talk about trying to read between the lines [X(]

RTK

My Feedback: (1)

bubbagates---I would check the timing. Mine has never even hinted about trying to start back wards.

bubbagates

My Feedback: (32)

Thought so, anyone know where it should be in degrees and off of which cylinder for TDC

Tired Old Man

My Feedback: (1)

Bill,

Now you understand what kind of people I get to fly with Worse, some of the things I've done to my planes, with and without any help... Totally bonkers, every last one of us....Worse, he may not be far off for the next vacation locale

But we do have A LOT of fun when we get the chance to get together[8D]

altavillan

My Feedback: (1)

About 6mm center to center same as zdz or when the magnet just clears the pickup

RTK

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Which ignition?? Falcon, CH (CH clone)


I understood that perfectly altavillan

altavillan

My Feedback: (1)

Tuning the carb; Best results happen this way. Do a couple taxi runs, Advance to full throttle don't take off cut throttle. The engine should hesitate just slightly as you advance throttle. Keep doing this till you get just a little tiny bit of burble as you advance throttle. This is to adjust the low speed needle. Then bring it back in and hold the plane at full throttle and set the high for max rpm. Fine tune from there. If burbling is persistent keep leaning the low very small amounts. Of course do all tuning engine off.

Tired Old Man

My Feedback: (1)

28-30 BTDC with CH or RC Xcell ignition. RTK knows where it needs to be with the Falkon. I understood it too

It's impossible to tune running with the mufflers on. You could try, but only once since you wouldn't have the hand after that......

RTK

My Feedback: (1)

Here are the detailed instruction for both-

http://www.ch-ignitions.com/CHinst.html


http://www.falkon.cz/download/en.pdf
http://www.falkon.cz/se.htm

altavillan

My Feedback: (1)

With all the cash you are coming home with I say lets put cans on your bird. And wait till you see my new way to mount the mufflers. This one I might have to patent!!! Corse it takes about a day to make them so maybe I'll post a picture of them and a boatload of them from China will be here next week and I won't have to make you a set.

Tired Old Man

My Feedback: (1)

The throttle servo is directly in line with the cans and would prolly melt in the first 5 minutes of running.

bubbagates

My Feedback: (32)

Thanks guys for the timing info, I really am not sure which ignition it is, as I mentioned it's not mine but he is looking for an answer to this and since I have been helping me with it, guess who gets the questions.... The good thing is he has very limited time to fly right now so I only get a very tiny amount of time to actually correct issues.

Now that posts makes sense. I was not sure what to make of it but I kinda got the idea prior to you answering me

altavillan

My Feedback: (1)

Bill, The ignition might be dieing. If it's the falcon it probably is. They signal an untimely death by hard starting, Starts on one cylinder and slowly igniting the other cylinder (sounds real cool). Eventualy only one cylinder will fire. Put a CH on it. Tell Terry it's for a BME and you will get one of the good ones.

bubbagates

My Feedback: (32)

Though possible I would hope not but hey, anything can happen. The engine probably has 1 gallon through it if that and it's been kicking backwards since day one. I never gave the timing a thought, my bad. I'm betting on it's advanced a tad too much. Now that I have the numbers, once I find out what brand then I'll look into it.

I've heard a couple of ZDZ twins run on one cylinder then the other kicks in at various IMAC meets. You're right, very cool sounding but kinda hard on the engine and airframe

CUAERO BUFF

Hello all,

I am currently working on an RC aircraft design project and have been investigating several engines that will provide at least 4.4 HP at a 5000 ft density airfield. I had estimated that I would need an engine rated at 5.41 HP at sea level to compensate for attitude losses. After researching engines, I had come upon the BME Xtreme 115 at 11 HP and the 3W-70I 7.5 HP engine. I had wanted to overpower the aircraft as the engine will be used in a pusher configuration and I don't know my power losses yet.

The questions I have concern performance and potential drawings. I read in this forum that the engine had potentially serious overheating problems (if it worked at all upon delivery). Now because of its SUPER light weight for the power, I thought that this would be a good investment. Should I worry? I only actually need 4.4 Hp at takeoff, so if I don’t run the RPMs up I should be okay. Yes?

Also, I was hoping that someone could give me a relative fuel consumption of the engine if they had it. That would help a lot in my fuel tank designs.

And finally, does anyone have Solidworks drawings of this engine? I don’t expect anyone to have this, but I was taught that all they can do is say no.

Thank you for taking the time to read this and even consider my concerns.

Cheers!

Tired Old Man

My Feedback: (1)

Your looking at an engine that produces over 12 hp for a 5 hp project. You might want to reconsider simply for that reason. A 50cc engine would easily meet your needs, and the BME 44, also a very light engine, just might fit the need perfectly.

Over heating is a user determined issue with any engine.

CUAERO BUFF

Does anyone have ANY idea what the fuel consumption (oz/min or such) of the BME Extreme 115 is?!

Also, what do the twin BME mufflers weight?

Any help would be appreciated as BME is afraid of phone calls and emails apparently!

altavillan

My Feedback: (1)

Stock mufflers weigh 9.4 oz Per pair.
Fuel consumption is 9 oz per 14 minute @ 50% power. About 2.5 oz per minute + two pistons and two cylinders per minute at 110% power. Slightly longer time before mortality on a 28" prop.

Actually never did damage the engine but melted the teflon canister exhaust coupling a couple times.