BME Xtreme update
 

A few tach numbers from the BME 110 and 55cc prototypes.

55- menz-s 24-8 @ 6200
Mejzlik 22-10 @ 7800
Bolly 19-8 @ 10,250 ! ! ! !

Seems the Bolly was a test to see of a rod or crank would let go. . .Apparently the engine is going to be turbine-safety certified. :)

ON a side note, the ASPCA has requested that future mega-rpm tests be done in an an-echoic chamber to prevent eardrum damage and psychological distress for all dogs within a 5-mile radius.

Final weight for the 55, without ignition or muffler, is now set in stone at 2 lbs 1 ounce, and the crankshaft balance parameters are finalized so production can now carry forward.

On the 110, the projected cylinder/piston production schedule is on track, and should arrive in the latter half of the month.

Power figures are now consistent on the prototypes with the engines spinning a Menz-s 28-10 at 6300 after warmup and the Mejzlik 28-10 in excess of 6700 (these figures are HOT engines). Power figures with tuned cansiter exhausts would improve 300-400 rpm depending on prop loading and design.

An evaluation of the current CH ignitions showed an inconsistency in timing retard at lower rpms, leading to development of a more consistent advance logarithm embedded in the timing chips. This should improve low-rpm smoothness and give the BME an even smoother transition than before.

I have 2 of the Xtremes on order. . would make a nice 4th of July fireworks display to fire both of them up on the back deck at the same time. :)

BME Xtreme update
 

Hey Kris...We're REALLY impressed with your knowledge strokes, and ignitions in particular..

Advance logarithm ???


Logartithm..n. The exponent expressing the power to which a fixed number must be raised in order to produce a given number..

ALGORITHM..n. A predetermined set of instructions for solving a specific problem in a limited number of steps...

If you can't dazzle 'em with brilliance, baffle 'em with BS.......

Keep up the good work.......... :D

BME Xtreme update
 

Is anyone but me tired of Kris blowing his horn around RC Universe. Geeeeze!!!! A wealth of misinformation, it seems to me.

fancman
 

You are not alone :stupid:

BME Xtreme update
 

Just so I understand this correctly...

Somebody posts some information on an engine that is of great interest to lots of people who read these forums, but that is not currently available. Then he gets lambasted by several people because of the semantics of his post. Nice job, fellas. So much for "fun" in the hobby.

semantics - (n) the study of meanings (see, I have a dictionary, too).

Ken

BME Xtreme update
 

Notwithstanding that you are factually incorrect (as evidenced by tests both here and at CH Ignitions), where and when did you personally perform the tests on the BME 110 that led to your assertion?

It is true that we are working with Keith to develop a timing map for that specific engine, however, there is no inconsistancy in the retard timing.

If you install an ignition with the 20 degree map selected and another with a 26 degree map selected there will be obvious differences, but no inconsistancy.

Ed Vollmer
M-E Technical, LLP

BME Xtreme update
 

Ed,

When do you expect the new 110 Syncro Spark/ignition module to be completed and how soon after that can it go into production?

Brian

BME Xtreme update
 

Brian, I prefer to let Keith make any announcements of this kind. He is the person doing the work - we are simply trying to assist.

Or.............perhaps Kris^ knows. :rolleyes:

BME Xtreme update
 

Ed, not to refute what you are saying, but I've seen it in my own engines that 'mysteriously" don't hold the proper timing at lower rpms sometimes. This "inconsistency" is most evident in the 1100-1300 rpm range, where sometimes the timing will be more advanced than others, usually on the scale of 5-6 degrees. This condition is always accompanied by roughness and the engine seeming to "hit" harder with each power stroke.

According to Keith, and I believe it from my own readings, the timing chips in the CH ignitions can start advancing the timing as low as 1200-1300 rpm, and if so this would account for timing differential at the "borderline" point for timing advance (or lack of retard) to occur. A simple thing like a tiny change in magnetic field from the permanent magnet, due to heating up or a small change in air-gap because of temperature changes, COULD be enough to affect the "dwell" time seen by the processor. After all, the processor senses the magnets speed and position as it passes the pickup, does it not? And then does a comparative search based on how many times per second/minute this is occuring to determine actual rpm and position of the crankshaft, THEN institutes the proper retard/ignition point from the programmed timing curve. Correct?

You had better believe I would not put it out on this list unless I had that sort of information directly from the source. The fact that you are helping out with this timing hassle is to be aplauded, Ed. I for one, really hope you guys get it straightened out.

As for logarithm vs. Algorithm. . I stand corrected. . .Oopsie, gee golly, I made a goof up. somebody please crucify me for making a mistake at OH-dark-thirty when my brain was only firing on 3 cylinders.

One thing to remember, Ed, Keith is not allowed to make announcements of that sort on this forum (didn't we just have a poll that said people didn't want manufacturers using RCU as a Sales Bazaar???) And if, in all the discussions I have entered in this forum I make one or two mistakes, I'm sure it's very few and far between. Excuse me for being only human, . . it happens sometimes.

BME Xtreme update
 

Have any of you tried a different brand of ignition on the BME (100, 102...1??) to see if they get smoother at idle? Seems easy enough to try. Falkon, DA, or the dreaded 3W?

BME Xtreme update
 

Helping out ? Ed is the manufacturer of the syncro spark chip...the ignition on a DA, 3W, ZDZ, RCS, etc.. is NOT controlled by a syncro spark chip..The ONLY ignitions that use this chip are C&H, RC, and Silent spark....
The low speed needle setting will affect the timing..If it's too rich the timing, controlled by the crank rotation, will not advance as fast if the low needle is too rich....
The ONLY timing that is completely controlled by the throttle is a C&H or an RC or a Silent Spark with mechanical advance connected directly to the throttle......
If you have an engine with C&H and you think the timing is inconsistent you would have to run it with a timing light and a degree wheel...Have you done this ?? Where does the timing begin to advance ? How many degrees at what rpm ? Anything else is pure speculation....
Only ignition in recent memory that had a "step" in the advance curve was the early Reichmuth...It would change rpm somewhere in the 1500-2500 range, from a few degrees to the final setting, around 28 degrees...a small change of 5 or 6 degrees at 1200 rpm would be barely noticeable in the running of the engine, if at all....If you doubt this, get a mechanical advance engine and try different settings..I have been making my own ignitions and mechanical advance units for 16 years, maybe I don't know enough about it yet.... :D

BME Xtreme update
 

Since those other "foreign" ignitions don't use the synchro chip, substituting one of those ignitions onto the problem motor would quickly tell you if it was an ignition problem or not. If the engine ran the same with the foreign ignition, one could conclude that the problem lies within the engine and not within the mysterious workings of the synchro chip.

BME Xtreme update
 

It would have to be a blind test...Problem being, the other ignitions don't use a Hall sensor, so it's not a matter of just plugging in the different ignitions to the same sensor....
It's possible that Keith has already tested a 3w or DA ignition already, anyway.....

BME Xtreme update
 

Falkon (ZDZ) uses a Hall sensor, but you're right on the DA and 3W.

BME Xtreme update
 

AS a matter of fact I have, RCIgn. Not with a degree wheel, but with timing marks scribed on the hub/crankcase for reference. Yes, the engine advances, and yes, sometimes it's dead nuts on "zero" reference at idle (1100 rpm) but come up a hair off that and it advances, and it does not always do it at the same point, nor always drop off the timing as the rpm comes down. I don't mind that it does this. . I'm not using that part of the power band to begin with, and it probably helps the motor stay running in the air during long low-throttle glides.

Personally, to me, the timing curve of the ignition is fine, and down at the bottom it's not worth worrying about. Heck, I would never have checked it if Keith had not mentioned it to me in the first place. But, it seems a difficulty was perceived at idle rpm, where the engine seemed to be "hitting" too hard, and causing the characteristic "BME SHAKE" that a lot of people find bothersome. IF Keith, Ed and others are taking steps to smooth this out, GREAT!!. . it can only improve the end product.

Now, if you'll excuse me, I have to go work with some logarithms and algorithms. . . .

BME Xtreme update
 

Before this gets out of hand let me say that we have been very satisfied with the C&H ignition and the Syncro Spark chip that Ed Vollmer produces. I have done some testing of the ignition and its processor. I have found that on our twins they would benifit from a different amount of timing at idle. Ed was kind enough to furnish me with some new chips with programs I requested. I will test them soon and let you know if they work as we expect them to. This is to assure the new engine idles as smooth as any other brand engine.

BME Xtreme update
 

rcplanefan,
All this technical jargon is just so much drivel to 99.9% of us who enjoy this hobby. If your engine doesn't run properly or the ignition doesn't work properly you get it fixed. What's the use of all the technical mumbo jumbo and who really needs the information? Thousands of these engines have been sold with little problem, so again, what's the point? I've read many of the posts and quite frankly, a lot of the information given is incorrect and biased to say the least. I'm sure all the TOC guys are not reading any of this because they know better. What gets me is the fact that so many TOC wanna be's are here reading this stuff as if it's come down from the burning bush. It just ain't so and is misleading to those who don't know any better.

BME Xtreme update
 

fancman - I agree. But rather than go through all the drivel, I wait for Mr. Vollmer, RCign, and Mr. Baker, and a few others to pop up and tell it like it really is - every now and then a little gem of knowledge pops out. Believe it or not, guys like Kris actually help bring the Manufacturers out of the woodwork when they would otherwise just lurk.

Speaking of pulling guys out of the woodwork, Mr. Baker, how long until the 110 hits the streets and Kris really rants?

RCign: I'm still hunting down that Motorcycle engine, its not going well, either its prohibitively expensive, or the dealer doesnt want to work with me... I'm going to junk yards now...

Roger

BME Xtreme update
 

I don't call it "ranting" DesertRat, I call it a "Frothing, mind-crazed, hyperzealous, pathologically-depraved discussion". . it could be worse. . I could drink my coffee first. Then it would be ranting. . . :D

Kris^

BME Extreme
 

I have really enjoyed all the BME Extreme stuff floating around all these postings over the last what is 18-months or so. I have owned 2 BME engines by the way. But really I think this new Hot Rod lite weight will come to be. And as soon as it does Keith will offer some updated cylinder spacers and your New 110 can be a new 112. And if that dont shake your tailfeathers wait 2 more years and the new EVO-EXTREME MAX 118 will really knock these DA guys down. Lets see 118X2= 236cc's of 4 cylinder rock & roll. Man oh man I cant wait. I think Im mind crazed and frothing. :confused:

BME Extreme 110
 

The word from our cylinder manufacturer is they will ship June 15th. If this holds true we will begin to ship engines around the end of June. We have around 400 people on the waiting list so if anyone here not on the list wants one they should give us a call or e-mail us soon. Our first production run is almost sold out.


Thank you
Keith
BME

BME Xtreme update
 

What if...

we provide the timing circuitry with the pulse width from the throttle channel. I do see the ability to use the throttle curve manipulation from our transmitter to fine tune the throttle band to an individual's taste/setup.

The throttle servo moves in proportions with the width of the pulse (1.5ms +/- 0.5ms), which would simultaneously be fed into the timing circuit. Both the servo and the timing 'know' what we want, i.e., idle, midrange, etc. I do not know how many points currently are available from the transmitter that heli guys play with. With a minimum of two points (in addition to 1ms and 2ms) we should be able flatten or steepen the part of the curve where it matters most to each engine/setup.

Such an ignition could be plugged into the receiver with an extra port into which we plug in our throttle servo. This would allow the servo to be placed close to where we mount the ignition unit.

BME Xtreme update
 

What if... (cont'd)

we plug our 'new' ignition into a separate channel. We can manipulate the advance/retard independently of the position of the throttle valve.

BME Xtreme update
 

Bob,

That sounds like a great idea. Just install a fiber optic cable to eliminate the noise. This could be the way of the future.

Brian

BME Xtreme update
 

My ball bearing "Model T" mechanical advance ignition is looking better all the time....Linear advance from about 4 BTDC to 28 BTDC at wide open...The K.I.S.S principle...
All this timing stuff is vastly overrated relative to engine performance..My .02 :D

BME Xtreme update
 

Why don't we go full blown with throttle position, crankshaft position, O2, exhuast gas temperature, and engine temperature sensors and use an automotive cpu to run these things????!!!!

BME Xtreme update
 

Check the price on the fuel injected OS engines...Some of us are too cheap....

BME Xtreme update
 

bdtsr. . I "adapted" a 4-cylinder GM car computer to see what would happen and if things were worth pursuing. . one injector, lowered the fuel pressure to 6-8 psi instead of 32-35, basically playing to see if it COULD be done. .

Okay, it worked, sort of. . not that I used the setup to actually run an RC engine, but by taking a tap off the crank sensor signal and feeding it to the automotive computer you got one injector pulse per 2 revolutions (batch fire with a distributor. . 2 pulses per revolution for ignition and one for injectors)

Would it be adaptable to an RC engine. . sure, if you wanted to take the time to do it. It CAN be done, but it was 3 weeks of trial and error and signal chasing, as well as cobbling up a crank sensor circuit to mate to the front of the test motor and feed the automotive computer. I got injector pulse, and ignition timing signal out of the computer, the rest is up in the air but I'm sure you could fiddle with sensors and values to adapt the stock automotive fuel and ignition strategies to our engines. . just a matter of time before someone succeeds.

I'll stick to the off the shelf items that come with the engines. . .they work pretty well.

BTW. . you would probably add a pound of weight and a lot more complexity than is necessary. have a go if you are feeling adventurous, though.

BME Xtreme update
 

KRIS^, actually I was just funnin' here. Your info is very good though. I'm sure someone will enter the market with something in the not so distant future. Hey at $1500 and up for a motor, why not dump another grand or so into a engine management system!

BME Xtreme update
 

OUCH!!!!!!!!!!!!!!!!!!!

Bad enough the steenkeen planes can go for $3000 each

BME Xtreme update
 

Going to reinvent the wheel again!!!!
Was here 4 years ago. It worked fine just was not "idot proof". To many things to twiddle with and ended up with a messed up engine ignition. If we ever got it working the next step was controling fuel injection from the same information .

BME Xtreme update
 

Imagine the modeller at the field. . scratching his head and looking at all those wires going from the engine to the CPU. . then out to the injector and ignition module. . . wondering what the heck happened and why it won't run . . .

I see enough cars on the side of the road to know better than to ever go there.

KISS. . and keep it as user friendly and inexpensive as possible. That's the best plan.

BME Xtreme update
 

tkg, Chevy had the same problem with it's mechanical fuel injection on the '57 Corvette. It ran just fine when LEFT ALONE! Too many people had to tinker with it and mess it up, which in turn helped cause it's early end. Now what do our cars have on them? Fuel injection! It's just a matter of time before it happens.

BME Xtreme update
 

The control systems and strategies used on automotive engines could be used on our engines - BUT - the cost would be prohibitive. I think we sell something like 2,000,000 units per year - so given that volume, cost per vehicle is ok. Given model aircraft engine sales volumes - forget it. Calibration engineers that know how to do it command a top dollar - and don't know what unemployment is. That coupled with vendors that develop and market components which can be bought for at a reasonable cost - it still works out ok for automotive. Our model engines would require retooling - sensors - controls - from scratch. Yes, it could be done but not at a cost any of us would pay. The benefits would be tremendous - I remember what we worked with 25-30 years ago - and that was more sophisticated than what we are using today.

Dan

BME Xtreme update
 

Let's see...

If we get a 'tick' every time the Hall sensor sees the magnet and wait a little before sending out a 'toc' to spark the plug. At full throttle of 10krpm we get a total time of 6 miliseconds between two successive ticks. At idle of 1krpm (for simplicity sake), we get 60 miliseconds (60ms).

For 28deg BTDC, we convert it to 0.46ms and 4deg BTDC converts to 0.67ms. Anything in between becomes our throttle curve, whatever we want it to be: logarithmic, exponential, or simply a bunch of imperical data.

We already exponential curve manipulation in our transmitter, i.e., no different than setting expo for aileron or elevator. We need to generate say 3,600 baby ticks every time we get a tick from the Hall sensor. Now we have 10 ticks per degree to play with.

We set up a fixed (and very precise) oscillator that is triggered by each tick. We manipulate how many baby ticks to wait before sending out a toc to fire the plug. We line up these baby ticks with our curve manipulation from the transmitter. My transmitter even shows the shape of the expo curve.

What I described above is being done by the syncho unit used by CH. CH makes excellent ignition units which use their tiny coil that can sustain 15kV. The rest of the circuitry was invented in the '60s.

The mechanical linkage is just as simple or complicated as what can be done as described. I do not see how we can not use an 8-pin PIC to do the job and then some. I do not see anything being expensive, complicated, or hard to use. Having said that would someone step up to the plate and get it done for all of us? As for me, I have to use the lame excuse that 'I just don't have time'.

The power of teamwork...
 

brings out the best in each member of the team.

I think it is excellent that an engine manufacture and an ignition manufacturer are working this close. It takes a lot of trust on both parties sides.
Not to mention that mixing a mechanical engineer and an electronics engineer is like mixing beer and wine.

You can do it, but it usually results in a big headache. ;)

Timing plays a crucial role to things like:

Throttle response
Torque (and therefore HP)
Fuel efficiency
temperature control
easy starting
built in governor control
etc., etc.

adding a simple TPS makes a big difference. After that, adding sensors does not bring the same large returns, unless you want to add fuel injection. Up to this point FI does not provide enough gain to warrant the expense, complexity,or weight penalty.

We, in the end, will benefit greatly!...I hope :)

OK, there's my two cents. :D


Scott

.
 

.

BME Xtreme update
 

I was curious about rpm numbers myself. Keith originally said the 110 'xtreme' was gonna turn a Menz 28-10 400 more rpms than the DA 100. The guys flying the prototypes haven't seen anything like that yet...they may still have some work to do on it to bring them up to the numbers they claimed... not sure about that though. They may just settle for what they have now and drop the 'xtreme' pitch. ;)

Forrest Gump was right
 

Ahem. . to set the record straight. . there are NO published numbers for the 110Xtreme at the moment, simply because there is only ONE of them in existence. It's on the nose of the BME test plane being flown by Todd Blose.

Any other "Xtreme's" out there, and there are a few 106 prototypes running around, are NOT the final product.

Now. . as for Tim Durbins statement about power compared to a DA100. . it is of course. . total hogwash (as are many other "facts" he regurgitates)

As for release of the 110, a conversation with Keith on Monday revealed that parts delivery is on schedule, and the motors should be shipping soon.

As for "power", Keith has mentioned 6300 with a 28-10 Menz as 'normal' power output for the prototype, wth the 27-10 Menz-s and 28-10 Mejzlik well in excess of 6700+. Remember, these are fully warmed up power numbers, usually after a flight, and not the "it's cold so it's gonna make more power on the first pull" numbers so often quoted.

Remember. . 3.8 lbs WITH plugs and prop washer/nut, 4.5 with mufflers and ignition (same as a ZDZ80, and a 3" larger prop), as powerful (if not more so) than the current 3w-106. This is going to be a VERY hard engine to beat when it comes to a total package of light weight, power, smoothness, and dependability.

BME Xtreme update
 

You have to understand that that 400 rpm is compared to Keith's DA 100. His numbers for that engine are below what most of us get on the DA by about 200 rpm. We confirmed that at the Waco flyin 2 or 3 weeks ago, we tacked a DA with a 27-10 NX and it was 200 below what Keith said the extreme will turn.

Tracy Hill