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.

RE: BME vs DA
 

Kris, if you had put that DA up at the beginning of the summer I would have been severely tempted to get it, but now all my money has gone to my 2.6M Extra. Timing can really stink sometimes. The 150 is such a sweet running engine, I'm sure I'll own one some day.

RE: BME vs DA
 

Here's my two cents with my experience with Keith at BME. Whenever I have called BME Keith answers the phone and he is very good at helping me with any problems that I am having. Awhile back I was starting my 105 and I got it loaded up and it backfired. About a week later it died in the air for the first time ever. After removing the carburator I found a broken reed valve and I called Keith and told him what I had found and he told me that was rare and it usually only happens if the engine backfires............oops! Keith mailed me new reed valves right a way at no charge. Sometime later I was having a problem with the front bearings on the 105--I found this problem on a Monday and I had an airshow to do the following Saturday and Sunday. I called Keith on Tuesday morning and explained the situation and he said to send him the motor. I sent it to him by next day air, which was on Tuesday afternoon, and he repaired it and sent it back to me next day air and I had it for the airshow with new bearings at no charge. I couldn't be happier with the service I have received from BME.

Big Bob Knudsen

RE: BME vs DA
 

To be fair, Kieth responded to my emails today. He told me I needed to send in my engine for possible bent crankshaft. Runout is .008 at the propshaft.

I never could get him on the phone.

Joe

RE: BME vs DA
 

I want to order a 110. I hear that there are problems with shipping the 110s out. So, I have sent three e-mails to BME over the past three weeks asking on status of 110s and to see how long a wait I would have. If the wait for a 110 is too long, I'll have to look at the DA. I have not received a single response.

RE: BME vs DA
 

Couch Flyer, give DA a call. You won't regret buying this engine. Here's a vid of my brand new DA hauling around my Extra. The engine gets better every time I fly it:

http://teamsolorc.com/johnv/CompArfRyan.wmv

RE: BME vs DA
 

If I may be so bold as to point this out. . .

In a bit of an impromptu "test" to see if my BME110/Composite-ARF 40% 330 combination was a viable competitor for the heavier CA40% 330's powered by DA and 3W150's, we held a "just for fun" drag race at the Mocksville IMAC contest after the competition was finished. About 50 people were on hand to watch the fun. :)

All 3 planes are 40% Composite-ARF 330's. Mine is a "lightened" version, that has a takeoff weight full of gas of about 30.5 lbs. The other two 330's were not weighed, but carried the "normal " equipment. The 3W powered aircraft had a 3W150 TOC on Tuned pefa Canister exhaust, the DA had standard DA mufflers. All planes ran Mejzlik propellors, 32-10's on the 150's and a 28-10 on the BME110.

The first matchup was the 3W powered plane against the BME110. The planes started side-by-side in the middle of the runway. 3...2...1...GO

The BME leapt ahead and was off the ground going vertical in about 15 feet. . .the 3W powered plane took about 30 feet to get airborne and by the time it was going vertical the BME was about 3-4 lengths ahead and gaining ground. After 10 seconds (unofficial duration limit) the BME110 powered plane was about 7-8 lengths ahead of the 3W 150 powered plane. . . we then broke it off and went flying for a while.

The second "Race" was BME110 vs. DA150. . using the same lineing-up and start process. . .this time the BME stumbled slightly due to a long idle period, and didn't get up to full power instantly the way it had before. When the BME plane broke ground so did the DA powered plane, and it was a dead heat at that point. 10 seconds later the BME powered plane was ahead by 2-3 lengths as the planes passed through about 750 feet or so, then we broke it off.

NOW. . .the results may vary from day to day, tuning setup and prop selection make a big difference, and a bit of "tweaking" may have gotten some more power out of any of the engines involved. The other two flyers, and myself, all run just a little rich on the top end of the power curve. That being said. . The BME's performance was ( to put it mildly) VERY impressive.

So. . you just gotta ask yourself. .

Which engine do you REALLY want???

These pics were taken of the "event". . the DA vs. BME part of the race.

Photo #1. . Combatants for the DA vs. BME part of the race venue. . On the left. . BME110 powered plane. . on the right the DA-150 powered plane. . Note the difference in propellor lengths.
Photo #2 .. Lined up and. . GO. . rpm's just coming up as the planes begin the race. . BME stumbled a little bit before it got going, so the DA has the lead at this point. . .

Photo#3. . It's a close race. . BME powered plane on the right, but closer to the camera from this angle.

Photo #4. . Both planes are a dot. . Witnesses reported the BME powered plane had a slgiht lead. . Either way. .both planes reached altitude in a BIG hurry.

RE: BME vs DA
 

As If some one could stop you?

RE: BME vs DA
 

A couple of questions for the BME guys. I'm reading all of this with great interest as I want to build a "quiet" 35 % but it kills me to add 2 or 3 lbs to an airplane. Makes sense to try a BME and put a set of cannisters on it and I end up with the same weight as something with a DA or 3W and regular mufflers. I must admit that I'm somewhat leery of the light weight BME. Hopefully that weight didn't come at the expense of needed strength but I guess there is only one way to find out. I've looked for dimensions on the 110 but can't find the distance between the mount plate and the back of the spinner. My other questions concerns what cannisters are being used and if headers are available or are you guys making your own. One more thing, do you have the distance from the exhaust port and the beginning of the cannister. I have a Carden 35% Edge on the table and am considering trying a 110 with cannisters in it which is why I'm looking for measurements. Thanks for your help.

RE: BME vs DA
 

Jlb, the f-r distance of the BME is right at 6 inches. For exhaust on my two BME Xtremes, I run a 90 degree elbow (25mm OD, from KS, available form DA) and home made flage (though flanges are now available), then couple that directly to either a "L" or "LL" Pefa canister available from Aircraft International. That makes one muffler for one cylinder, so you need two of everything.

Sound signature will depend on how fast you are spinning the prop. . a 28" Mejzlik at 7000 rpm will be 3-4dB louder than a 28" biela or Menz at 6400 rpm, and with the thrust from these props going to the biela or menz is really a better idea. the Mejzlik just spins so fast it stops increasing thrust at some point, so all that rpm is wasted.

As for balancing the plane, my 40% Composite-Arf 330s has NO lead in the nose, the batteries, rudder servos and fuel tank are on the wing tube, and its actually slightly nose heavy. On the 33% CA330 it was difficult to keep the plane NOT nose heavy, and all the servos and batteries are behind the CG in order for it to balance correctly.

All-up weight of a BME Xtreme, shorty headers, "L" canisters and ignition is right at 6 lbs, or slightly lighter than the DA100 or 3W 106 weigh with standard mufflers.

RE: BME vs DA
 

JLB, the mount to spinner distance is 6 inches. Matter of fact, since the 110 and the 105 share the exact same bottom end, most of the 105's measurements apply. Major difference is the spark plugs on the 110 face back toward the rear of the engine, and the plug cap to plug cap distance is 10.5 inches.

Regarding strength, the Extreme bottom end has been in use since early spring (in the 105), and had there been problems with it, we all would have heard about it. Take the 105 and swap in the 110 cylinders and pistons, and you've got the 110 Extreme. I had zero problems with my 105, and anticipate zero problems regarding strength with my 110.

I had used the K&S cannisters for 70cc cylinders with my 105 (my first use of cannisters) and yep, I made up my own headers using parts from Desert Aircraft. I had zero problems with them either.

For my 110, I followed Kris' suggestion to use the larger Pefa LL cannisters (still a lighter combination than DA or 3W with regular mufflers) and gained 300 rpm. I again made up headers, also following Kris' testing and used simply a shorty header/90 degree elbow giving an exhaust outlet to cannister inlet length of less then 5 inches. The Pefa LL headers ARE big with a 2 3/4" diameter and 16" cannister length. The Pefa L headers have the same inlet and outlet size and the same diameter, but are only 12 1/8" in length and may solve some fit issues if you don't have room for the "bigguns". My Wild Hare Extra does have room. BTW the K&S cannisters for up to 70 cc cylinders are 2 3'8" in diameter by 9 7/8" long so are even smaller in size. I used a 10" header length per DAs suggestion. The K&S are available from DA at http://www.desertaircraft.com , and the Pefas are available from Aircraft International at http://www.aircraftinternational.com/ .

I'm not an expert, jsut learning as I go. I'm just on my second gallon through the engine, and am 400 rpm down from the 6,900+ rpm Kris reports with a similar setup using a 28x10 Mejlik prop on his well broken in 110. I know it'll get better, just takes time and learning how to do it. Even now, though, the 110 YANKS my 30 pound WH Extra out of a hover and runs skyward until it's a dot in the sky! Yeah, so far, so good.

RE: BME vs DA
 

Hey, Kris chimed in with his reply while I was still writing mine! :D Well he's the guru anyway.

RE: BME vs DA
 

Thanks to both of you for the information. That sure is one compact little rascal isn't it. The numbers look good and I should have no problem at all fitting that in the Carden. I'm starting to get pretty excited about this and that takes a bit after all these years. I just wish it wasn't the end of the flying season. Oh well, when the snow clears I'll have a new quiet Carden Edge and a new Ziroli P-38 added to the stable to get up and running so next season sounds like a great time. Thanks again for your help.

RE: BME vs DA
 

Kris,

I have a buddy selling a BME 102 converted to a 105. Should I wait for a 110, or get the 105?
I do like the compactness of the 110. Will it hold up over several years of IMAC flying? I intend my next gas engine to last a while.

Thanks

RE: BME vs DA
 

How was it "converted" to a 105, Couch-flyer? If it was done at BME, using the 1mm longer stroke crankshaft, then I'd say your idea is a very good one. Even if it was "only" a 102, upgrading it with 110 jugs/pistons would STILL be a tremendous power increase with a displacement of about 106 cc's and enough power to match the 3W106 in every respect.

I currently have the 110 and a modified 102/106. The 110 is just silly with power, but the 106 spins very nicely too, hitting 6150 with unbroken-in jugs using a menz-s 28-10, and hitting 6650-6700 on a 28-10 mejzlik during the same test session after only 1 gallon of gas through the new cylinders.

I'd grab it and run with it Couch-flyer, especially if the price is low. :)

RE: BME vs DA
 

The 102 was converted by BME to a 105. Which prop do you like best? Do you change props when you do 3D?

Thanks

BYW I am going to install the engine in a Wild Hare Giles 202.