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????!!!!

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

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.

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!

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

Bad enough the steenkeen planes can go for $3000 each

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 .

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.

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.

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

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'.

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.


Scott

.

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.

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.

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

OK, Since Mr. Kristen D. Welter has again shown he blabs stuff without any FACTS, or knowing what he is talking about at all. I will state that my post was in reference to what Keith stated the new 110 was projected to turn on the SA list on yahoogroups. Most on there (which Welter is not because he was banned by the moderator for pretty much the above behavior ) have seen this e-mail, which I could probably find if it was necessary, however it's not. T_Hill obviously knows about this and gave me the answer.

T_Hill,
Thanks for the straight scoop. It's apparent that you have first hand knowledge with this which is what I was looking for.

It is no secret that I am a fan of BME engines. At the same time though I am willing to admit that the BME line of engines have YET to prove themselves as the POWERHOUSE to beat. They are competative in respect to power, but so far that has been the best I can say about them. When it comes to weight savings, BME is leading the pack. So what the heck am I saying?......You have to know what PACKAGE you want to have......a little heavier with additional power (DA and 3W) or light weigh with average power (BME)

BME is pretty much AVERAGE in respects to power. When you compare all the other engine IN THE SAME CATEGORY, BME does not come out on top nor finish last. You either get less performance and more weight (Zenoah)......Average performance and a little lighter (BME)......Or all out grunting power with all the power to boot (DA and 3W)

As I stated, I am a BME fan......I have 2 of the 55 XTremes on order and thinking about getting a 110.....It is a matter of time before Keith figures out how to get the power to go along with the light weight. When he does, THEN HE WILL HAVE A MONSTER.

Keiths tach ahs alwasy showed 200-300 rpm less than anyone elses for some reason, Aero. . it's been reported so many times (by me at least) that i take it as a given. When keith, therefore, says 6300 with a menz 28-10, does that mean 6500 on everyone elses tach? An interesting question. So, if his engine is turnign 400 rpm stronger than HIS DA100 comparision motor, it's a pretty good indication that it will be 400 rpm stronger everywhere else too.

I have seen reports of the 3W106's at 6300-6400 with the menz-s 28-10 . .which puts the Xtreme (yes, it is) right at that powerlevel, which (as everyone knows) is substantially stronger than a DA100 by a GOOD 300-400 rpm. Then again, I've seen 6000 as the rpm for the 3W106 from several reports on this forum. Kind of makes you wonder who is more accurate.

400+ rpm stronger than a DA100? I have absolutely NO doubt about it.

As I said before. . hogwash.

Kris,

The rpm spread from the best to worst motor from any manufacturer is going to be 300-400 rpm. If you want to believe the lies being told over on the latest ZDZ 80 thread it's more like 800 rpm. The rpm for any wood prop from the same manufacturer is going to easily be another 200+ rpm. So arguing even a 200 rpm difference between 2 specific motors is a waste of time. Now if someone wants to buy a dozen of each motor and send them to me I'll be glad to look at the average difference between them. I just hate hard work but I could force myself to do it. Do some 3W 106's turn 6000 and others turn 6400, probably yes. I've got 4 DA's they have about 250 rpm spread. Do you really think that all BME's will turn the exact same rpm. Now I'm not bad mouthing BME, did my best to talk Keith out of a motor to replace the ZDZ in my Troybuilt light. I just can't justify/afford another 35% class motor, I've got 6 of them already. It will be interesting to see the numbers when they get them out. Might have to buy one anyway.

Tracy Hill

.

Here are the real numbers we get. Remember same prop, same tack, same fuel, same day. All tuned for maximum performance.

DA100 28x10 mejzlik 6300

3w100 toc 28x10 mejzlik 6400

BME 110 28x10 mejzlik 6700


You do the math and see what the numbers are. I have a test pilot in New Mexico testing a BME 110 with less powerful pre-production cylinders turning a MCS 27x10 at 6400 out of the box. There was a guy on RCU that said his DA100 was turning that prop 5700. The DA100 we tacked at the Waco fly-in was noted as being the strongest DA out of four or five other DA's and it turned an Airwild 27x10 at 6100 rpm. We get 6300-6400 on that prop. Were not knocking DA it is a fine motor and runs exeptionaly smooth but us forget the Extreme thing? No Way its more powerfull and weighs two pounds less than the competition. How can you ignore that?

Keith
BME

Aero330,

I sure would like to see that e-mail I posted about the new BME110 turning a 28x10 menz at 6400. I am not saying that I didnt say that but I sure dont remember it.


keith
BME

Aero330,


Who do you know flying a BME110 and what rpm did they quote you?


Keith
BME

I love engines and the detailed discussions about them.

If an engine's ignition system uses a rotating magnet to generate a timing signal, what kind of sensors other than a Hall Effect sensor can be used? I thought that Hall was it.

Tracy, I totally agree abou the "spread" of rpm engines can have. 3W's have, for years, seen 200-400 rpm difference in their engines output, depending on a number of factors. One or two of my own personal engines exhibit the same tendency to not always give me the same power output. . losing as much as 200 rpm with the same prop for no apparent reason, then never quite recovering their former power level even though a number of things are changed to try to get it back up. Others are a total beast compared to their exact counterparts, flown by other people.

Day to day power numbers vary, everyone knows that, and there will always be "weaker" or more potent engines of the same make and size. What has come to issue here is that yet another uninformed person is trying to denegrate a product he has NO knowledge of, as this same person does for anything he does not personally use.

The Da100 is a fine engine, as is the 3w106. I'm just glad that Keith has gone through the effort and worked his BUTT off to give us a third choice, one that is (by all standards) a better choice than it's competitors.