BME vs DA
 

Is there much of a difference between these motors in performance for the twin 100 size?

BME vs DA
 

Here we go again! Kris where are you?


Doug

There is now
 

My new BME 110 Extreme is turing a full 200-500 RPM more than the DA 100s here locally on a 27 x 10 MSC prop. Couple this with the BME being 2 pounds lighter and there is a very noticable performance increase in power, acceleration and wing loading.

Len

BME vs DA
 

Say Len:
What's your serial #?
I'm curious how many Extremes are out there.

RE: BME vs DA
 

Diablo, Len has one of the pre-production prototypes, #2 off the builders table, with #1 being in Todd Bloses plane. Mine is #3, the first "Production" engine.

As far as the BME110 vs. the DA100, there is NO comparison, power is substantially more, weight is substantially less, price is the same, reliability is the same.

Please see my other responses on BME related threads concerning actual power numbers with different propellers.

RE: BME vs DA
 

The way we grossly overpower our airplanes today... Who would notice?[8D]

RE: BME vs DA
 

That's what the Democrats say about social programs, Warren . .who would notice. .

Fact remains .. lighter planes fly better. .save 2 lbs, you save a lot. Gettnig more power on top of it is a definite plus.

RE: BME vs DA
 

Well, I was aiming more at the 200-500 RPM number... A bit dubious.

The 2 pounds is great if you don't then need to add 2 pounds to the nose...

RE: BME vs DA
 

When did we start measuring reliability in weeks?
Sounds like more of the same old BME hype to me.


Doug

RE: BME vs DA
 

Stomper, the bottom end, crankcase and bearings of the BME have proven themselves for over 3 years now, with the same bearings, rods, and crankshaft design being used for that length of time in the "102" series BME's. Except for an occasional bearing failure (which all the engine makers have) there have been ZERO broken crankshafts (DA and 3W both have failures), no rods spitting out the sides of the engine, and the design has more than proven itself.

If you want to worry about cylinder/piston problems, think about this for a minute. The same techniques and facilities that mold and machine the DA pieces also produce a LARGE number of 3W castings and pieces, as well as the BME pieces. . (Little place over in the Far East)

Remember the "flaking" of chrome from 3W cylinders a LONG time ago??. . .Seems they changed their manufacturing "technique". . .moved it to a more reliable facility it seems, and have been using that facility ever since. They also went to Nikasil. DA uses chrome plating, and BME uses Nikasil. All are proven technologies, and all are applied by industry specific techniques that ensure the best quality. . from ALL those makes of engines.

Take your "reliability" red flag down. . .the skies are blue, the weather is fine, and it's time to fly.

RE: BME vs DA
 

Well the 110 over the 100 should have 5% more power, so that may contribute to the 200 RPM.
However, the bigger engine being lighter is a good accomplishment.

One question that is valid ... would you need more nose weight to compensate.
If one takes the time to plan ahead, it could be a nice weight savings.

I have a DA-50 and it runs fine. Time will tell if it is reliable.

All the major manufactures seem to have good engines. Picking depends on personal preferences in some cases ( rear induction, carbs out the side of cowlings, reed vs rotary, mag vs electronic ignition, etc.). Some things are important to each individual, some are not.

But dependability is needed by all !!!!

RE: BME vs DA
 

Everytime I see one of the BME vs DA vs 3W discussions I just chuckle. They all make good stuff - if you get one that runs reliably, you got it made. As far as the BME Extreme 110 - I am # 40 on the waiting list - ordered mine last year November - and I am still waiting. So in the meantime, I flew 3W and DA all summer. What's the best one - the one that started and ran so I could have fun flying. One or two hundred rpm more or less - one or two pounds more or less on a 24 pound airplane - won't put me in the world class pilot category - but I did have fun flying all summer.

Dan

RE: BME vs DA
 

Mine is a limited experience,
But I've noticed that most 3W's I have heard running seem to not have as smooth an idle as my DA. There may be many other factors (Such as mounting-fuel tank-etc) so I'm not bashing anyone, just my observation...
RickP

RE: BME vs DA
 

Rick, "smoothness" is a direct function of port design and duration, and ignition timing, as well as how much compression an engine has. If you look at a DA, 3W, or BME (top 3 100cc "class" motors) you notice a few design differences.

For the DA, the intake ports use ports in the piston skirt with matching ports in the cylinder wall on one pair of ports, and the others have obviously high-velocity designs, all of which promotes very smooth bottom and mid-range running, at the expense of a little top-end power lost.

The 3W has about the same exhaust timing as the DA, but has wider and less "refined" (for low rpm usage) intake ports, so the mixture has to get moving faster in order to promote cylinder efficiency. This requires that the engine not be idling, but be in a slightly higher rpm range than the DA for smoother running characteristics. The 3W basically "comes alive" when the ports start flowing properly, so the midrange and top end are better on the 3W. That's how the 3W guys like to make their engines run.

BME has taken a slightly different approach, using more intake ports, with higher velocity designs but shorter duration. This is effectively called a "short-duration, high efficiency" port that works well at lower rpm, but still has enough area to allow good high-rpm power. BME also uses 6 ports instead of the 4-5 that DA and 3W use.

DA and 3W use about 152-155 degrees of exhaust duration, whereas BME uses 170 degrees of duration. This shows the designers intent on how the exhaust system should be designed for each brand of engine. DA and 3W will get moderate gains of 200-300 rpm from an optomized "canister" muffler setup that is properly tuned to the correct length, whereas the BME is actually designed for these types of exhausts and will get a much stronger increase in power when a properly tuned system is in place. Expect 500-600 rpm from a "tweaked" exhaust from the BME.

What this all boils down to is that each engine has it's own design parameters and running characteristics. The DA WILL have the smoothest idle (which impresses a lot of people and is great for sales), simply because it is designed for that, as well as a "smooth" transition and mid-range. But, do not expect the DA to make as much top-end power as a 3W. The design trade-off basically prevents this. It's not a LOT of a power difference (whether DA owners want to admit it or not) but it's there, on a consistent basis, and about 150-300 rpm in most cases compared to a comparable 3W using the exact same prop

The 3W, conversely, WILL have a slightly rougher idle, and a greater tendency to "burble" in the lower mid-range while in the air and unloaded, but the engine is substantially stronger on the top end, which is what the 3W guys intended.

The BME, on the other hand, is an entirely different animal, and exhibits idle/midrange characteristics close to the DA, but is just as powerful (if not more so) than the 3W 106, with the added potential for even greater power boosts if a properly tuned exhaust is added.

The differences in engine design are the main reason you see people going gah-gah over one engine brand or another (then there's the marketing hype as well). Some features scream out "better design" to people who expect an engine to run a certain way. Guys who like the butter-smooth idle and mid-range will prefer a DA, usually. Guys who like a decent mid-range and very strong top end power will probably prefer a 3W. And after people learn the new running characteristics of the BME (110) there will be a hard-core following of THAT engine.

Hope this explains it.

RE: BME vs DA
 

Hey Kris,
That was a crystal clear explanation. I appreciate your insight and detailed description. It also confirms that I did choose the motor suitable to my liking. I spend little time at full throttle and prefer pricise control throughout - even sacraficing top end a little, so the DA makes sense for me I guess.;)
Thanks
Rick

RE: BME vs DA
 

I will be very interested in seeing the new BME- ---
currently - we see DA's -a lot -and have plenty of respect for th easy to use natuere of these engines .
We also have a new 106 -(customer's engine ) which we will be sorting out for him in his new model . A nice lookin setup
Also we have a new ZDZNG 100 -which is pulling a 28 lb wild Hare Extra -and has plenty of power for the Unlimited sequences flown with this large model.
It goes to Tuscon for the Shootout in two weeks -
One engine mfgr noted that ZDZ finally learned to cast ported sleeves -
from what I have seen recently - they learned it very well -
Personally -I rate it very favorably with the DA- ( also very smooth and user friendly)-
Power -is a pissing match - so I won't belabor that point.

RE: BME vs DA
 

Great turnaround on my engine

RE: BME vs DA
 

that's funny, every time that I have called, Keith answered the phone. And every email I have sent (and that has been several) have all been answered, most in a matter of hours after I sent them. I am waiting for a 110 right now and Keith sent me a drawing so that I could go ahead and have my headers made (I tried Kris^'s method of resizing a pic but felt better if I had an actual dimensioned drawing so Keith mailed one to me no problem. received the drawing 3 days after requesting it)

RE: BME vs DA
 

Kris^

If I am reading you correct, BME makes the best "all around" engine .... if it fits the cowling ! ... correct ?

RE: BME vs DA
 

Have to disagree with you. Keith is a very busy man but has answered his phone when I've called, went out of his way to save me money by shipping me a new carb by wrapping it in bubble wrap and putting it in a blue label envelope instead of a box which would have doubled the shipping price and making sure that I got it within two days time.

As far as having a engine repaired by his company, you don't have to call him, just put in a letter what you want done and ship it off to them. If they don't understand your request, they will call you for confirmation before they do anything to it. That's standard procedure, just like it says in the manual. I just sent in a BME engine that was in a crash. Simply told them to please check the crank and put a new one in if it needed it. Also to go over the engine and repair/replace what is broken and if they have any questions to call me. Now it's only been a week so I can't tell you how fast the turn around will be, but I'm sure it will be soon. The company & Keith have never done me wrong and so far parts service, questions and follow up has been outstanding. They've gone out of their way to make me feel like I'm their only customer.

Maybe you've just called at the wrong time, try again. Email is a different story. All companies (not just BME) receive thousands of emails every day. At that rate they would have to hire someone 24/7 just to sort them out and answer them. Keith is only one person and a small staff. They will answer their emails & phone. Give them a break, try again on the phone call. I'm sure they'll take care of you.

RE: BME vs DA
 

Kris^:

Excellent post. Maybe should be nominated as 'post of the year'! Maybe, just maybe it will put to an end the 'engine wars' ([sm=punching.gif] ) Also informative, thank you. Hope we can all get back to flying now......

RE: BME vs DA
 

Hold on,
Let me fuel up my DA ;)

RickP

RE: BME vs DA
 

I'll be there with you, but I'll have to fuel up my DA, my 3W and my BME!! :D

RE: BME vs DA
 

Mustangfan, "if it fits inside the cowl" could throw the DA and 3W right out of the market, since both engines are at LEAST .75" wider than a BME. :D

Also, the rear-facing plugs on the BME are a BIG plus because the rear area of the cowl is wider than the front, and plugs projecting straight out or up or down will hit the sides of the cowling much more quickly than plugs facing aft.

As for "best all around". . . .in MY opinion, since I've owned all three brands and am very familiar with the shortcomings and limitations of each. . I'd have to say YES. . the BME is the best all-around engine in it's size range, easily making as much power as it's competitors, being as tractible adn smooth int he mid-range as either of it's competitors, saving 2 lbs of weight, costing the same, and with design features and considerations that make it a more user-friendly engine in some cases.

People will always argue over which is "Best". . . now, though, instead of the same old same old, we have the BME. directing a lot of energy and design perfection into the smallest, lightest, most powerful (yes I said that) and best designed engine in it's class.

Anyone want a DA150????? mine is for sale in the "Classified" section.

RE: BME vs DA
 

Kris^

Thanks for the info on engine design. That does help me in deciding what engine to purchase.