CAPtain232

My Feedback: (40)

I TOTALLY AGREE.......

It may shake (most likely), but how much we do not know. I believe that it will have very close to the HYPED power/performance as stated from Keith. I also agree that all up weight may only be 10 oz less than the lightest engine on the market now.........

10 oz is 10 oz and when speaking of planes like the 29% AEROWORKS EDGE or some of the other 80" and smaller planes, 10 oz is quite a bit.


As far as the shaking goes........IF there is a performance gain, is it worth it TO YOU?......that is truelly all that matters.
Are you willing to maintain the airframe for a little more power?

SuperJ

Stalker is not the airframe.

Kris^

My Feedback: (1)

If I may interject, Michael. .the Target weight for the 55 is WITH sparkplug and radial mount already on the motor, and the standard BME muffler is 4 ounces. Given these inputs, the weight goes as follows:

Motor, with plug and mount- 2 lbs
Standard BME muffler- 4 ounces
Ignition- 5ounces
battery and switch- 4 ounces (1000 ma 4 cell NiMH is 3 ounces)

This gives a weight of 2 lbs 13 ounces. The 2 lbs 2 ounce weight Keith quoted me was with mount and plug installed.

Even if the total weight, ready to fire, is 3 lbs, this motor is still an extremely lightweight powerplant, being lighter than a G-23, G-26, RCS140, RCS 180, ZDZ40, or any of the other small gas engines at their BARE weight.

To compare a YS 120/140, Saito 180 or larger, Moki of any sort, Big ST or OS Max, or any other glo engine to this motor is really a far-fetched exercise in futility. A lot of people love to quote a YS140 at 2 lbs 1 ounce. . but how much does the muffler weigh? 6-8 ounces? then add in the 4-6 ounce mount for the engine and you are quite easily up near the 3 lbs mark. We could even throw in a 4 ounce on-board glow system and pressure line to the tank for good measure. . there's an easy 5 extra ounces.

Suffice it to say. . everyone can make a big thing out of arguing about the BME55. . No matter what its final weight, it's still going to be a lot lighter than any comparably sized gas motor, and if the production motors follow the same power as the non-optimized prototype, it will easily be the most powerful engine in it's size range as well.

Kris^

My Feedback: (1)

Quote: As for the peformance of the YS140 mine will hit 106-111 mph on my Stalker in level flight in 70 degree weather which is around 10,000 rpm with that 18 x 12.

Then what IS a Stalker????

mglavin

My Feedback: (31)

Target weight or not 2lbs-2ozs was quoted by Keith at one point, I believe it was a proto-type.

If the engine does weigh 32ozs. with a 2.5oz. radial mount with bolts, 1.6oz. sparkplug, 1.4oz. prop washer/nut/stud or bolt, were talking about a bare engine weight of 26.5ozs. A YS 91 weighs 26ozs.?????

I'll believe it when I see it... Like I said previously this will be a great engine "IF" it holds up. Secondary to light engine weight airframes will have to built around this BEAST, the gasser subject airframes to considerable loads as compared to there glow cousins. Not to mention the airframe will have to built with an extremely light tail section to take advantage of the combined power packages lighter overall weight. I don't suggest you can move stuff around to accommodate the need, it's not going to happen without some serious redesign work. In the real world owners of the models that will be able to utilize this engine will be adding additional weight to the nose of the model to make it balance, until such time models are introduced that are lightweight and designed for a 3lb. power package in the 80" arena.

I quoted actual weights of known components that I have. Battery size and technology will obviously vary [I quoted a 1650mAh 4-cell NiMH] as will the type and brand of exhaust system. Very few if any will be using the noisy down tube exhaust diverters offered by BME or any other's for that matter.

mglavin

My Feedback: (31)

"STALKER" or Stalker-Pro is a brand of radar gun. I have one doesn't everyone.

Some of us like to fly fast and turn left when were not trolling slow and tossing the model around.

SuperJ

Click on the link above and find out. The correlation from power output to speed would be lost on you wouldn't it.

rcpilot44

My Feedback: (1)

It will be nice when the weather improves and everyone can get out and fly. It seems that a lot of people have cabin fever!!

Kris^

My Feedback: (1)

Super]

I am getting some extremely negative vibes from you. . .it seems you have made this a personal vendetta to nay-say and attempt to contradict almost everything discussed.

Fact is, the BME 55, when it gets here (someday) will be a tremendous step forward in both power improvement and weight removal from an engine in the 50-55cc size class. Whether the final "maxed out" weight of the 55 is 3 lbs, 2lbs 8 ounces or 3.25 lbs does not really matter. Right now, Keith Baker is within 2 ounces of his target weight, and well above his power output level. That tells ME that the final product is going to be VERY good indeed, and that eveyone else, including all the glow guys, is going to be playing catch-up.

Now, admittedly, Keith WANTS 1.99 lbs final weight, with plug and mount. he may have to ditch the mount to get it, but rest assured he's GOING to try to get it there. And, even with a "worst case" scenario, the engine will gross no more than 3 lbs installed and ready to run.

Iis the nature of 2-stroke engines that they are going to be lighter than 4-strokes of the same power level. It's just the nature of the beast. nothing agaisnt the YS140. . at it's current price, though, it's far more expensive than a comparable BME55, requires much more expensive fuel, makes about half the power, and weighs within a few ounces once all the installation is said and done.

I REALLY hope some pattern jocks get the "stones" to try a BME55 in a pattern plane, using a 3-bladed prop and quiet pipe to out-silence the big 4-strokes. It would be interesting to see how many "hard core" YS guys make a quick switch to more power for the same weight

Then, you have to remember. . .a Gasser, unlike a glow motor, leaves NO smoke trail. . I wonder how many points Pattern jocks get gigged when the judges can easily see the bobbles and miscues just by the exhaust trail from the engine. . . Imagine going to a Meet and having NO exhaust trail to give away your mistakes. . . . Gee. . ANOTHER point in the BME55's favor. .

azhar

My Feedback: (19)

Not to knock anybody, but wouldn't vibration become an issue if the engine is that light. It seems that the Saito's shake quite a bit more than the YS engines. I thought that reason for this was because of it's lightness. Another thing to consider with an engine that light is its durability in the long run. Again, I have heard more Saito's throwing a rod because of the same reason.


If I am wrong, please enlighten me.


Azhar

Diablo-RCU

My Feedback: (1)

Let's try this bare weight thing again. A Supertigre 2300 is a very light 23cc glow motor at 31 oz bare - no muffler. I can't see any engine with twice the displacement weighing about the same.....doesn't make sense. The ST has a steel sleeve (adds a few ounces), but a gasser has a heavy Walbro carb and a reed cage and a spark plug. The crankshaft and bearings of the gasser will be larger and will weigh more, the crankcase must be larger and will weigh more, and the cylinder will be larger and will weigh more. Go ahead and stare really hard at the Supertigre and tell me where you could reduce weight and double the displacement.

Kris^

My Feedback: (1)

it all depends ont eh overall engine design, how well teh piston/rod is counterweighted and how accurately it is done, as well as how rigid teh engiens structure is. What a LOT of people misconstrue as "vibration" is actually torque wind-up of the airframe due to a light motor, heavy firing pulse, heavy prop, and less than rigid airframe. You get a good solid power ulse coupled to a heavy prop, then have a lighter engien ont he firewall so less of that pulse is damped by the anti-flywheel effect of the engines mass, then you have a slightly flexible firewall and front structure assembly and it will all result in the forward part of the airframe winding up and rebounding once per revolution, giving a "vibration". Best bet is to make SURE the front of the plane is as rigid as possible, solidly mount the motor, time and adjust the carburetor for the smoothest idle, and use a lightweight prop. My BME's have always idled extremely smoothly, mainly because I made sure that the forward part of the fuselage was VERY stiff, so no torsional windup could occur. They Idled as smoothly as a bus, just sitting there purring, even with a heavier mejzlik prop on them.

Every single, however, has a dynamic imbalance that cannot be gotten rid of in the 2500-3500 rpm range usually. It's just the nature of the engine design, and is impossible to get rid of using only crankshaft counterbalance weights. ZDZ actually retards the ignition timing slightly in this "dynamic imbalance zone" to help reduce the "perceived" vibration level, although the actual dynamic imbalance is still there.

Kris^

My Feedback: (1)

Well, diablo, look at the BME102 versus a DA100. . the 102 actually DOES weigh 4.4 lbs WITH plugs while the DA is about 5.6 or so. They LOOK the same size, so where is the weight savings on the BME?

Study photos of the two engines and I'm sure you will be able to see where the weight difference is.

lcgj

My Feedback: (2)

we are talking about a high performance two stroke engine Its not going to be your mommies 4 banger. this sounds like what I need for my DP extra because its light and puts out lots of power evan at my elevation wich 5000 ft my moki just puts 15lbs of thrust up here. where can I order one

Kris^

My Feedback: (1)

www.bmeengine.com

(254) 836-0835

Email is [email protected]

mailing address (not updated on the website yet)

Baker model Engines
325 Whitetail Creek
China Springs, TX 76633

CAPtain232

My Feedback: (40)

Well let me tell you all...........

I am a big fan of BME as some of you know.....BUT am I ever getting tired of VIRGOROUSLY discussing what doesn't exist.

I have actually started threads JUST LIKE THIS ONE....only because of MY excitement. From my experience with BME and KEITH, he is about 90% right on what he says he is going to produce. SO I AM EXCITED as I like to fly 1/4 scale planes (for the shear simplicity of transport and storage) and I feel that this size engine with the HYPED LOW WEIGHT will be just the ticket I am looking for. I definitely agree that some of the bigger planes that were meant to fly with a 50cc engine were not designed with a "SUB 3 lb." engine in mind, so yes you may have to add lead. While the added "DEAD WEIGHT" is not desireable, I think it would still be a better PERFORMANCE combination. There will be PROs and CONs to ANY engine with a design like this.

I WORK HARD to get MY planes as light as I can...an engine like this will help tremendously.

When I build a plane for someone else, WEIGHT is a factor, but STRUCTURAL SOUNDNESS is most important. In most cases like this and with the designs that are out there TODAY, the benefit of an EXTREMEly light engine will not work due to balancing issues.

My suggestion, let it rest and see what happens.........

Kris^

My Feedback: (1)

HEAR HEAR !!!!!!!!!

HUZZAH HUZZAH HUZZAH !!!!!!!!!!!!!!!!!

I HEARTILY AGREE!!!!!!!!!!

Shortman

My Feedback: (21)

the answer is to wait and see! hehe

rcpilot44

My Feedback: (1)

I hope Keith hurries up with his new extreme 55. I have a WM 300 Extra built and the servos will be going in next week. I don't mind waiting but I hope the 55 is not delayed. Besides the weight diffrence to the DA 50 do you think it will put out more hp than the DA 50? I haven't heard much about the DA 50 for sometime. Does Keith know how much hp the 55 will be putting out? Is it easy to hook up the throttle linkage on a BME, The DA seems pretty easy....

Kris^

My Feedback: (1)

rcpilot44

As far as I have heard quoted, the Da-50 is turning the Mejzlik 22-10 in the 7100-7300 range after break-in. It has not been out very long so there has not been a ton of feedback on its power numbers. There have been posts suggesting that certain mufflers REALLY kill the power, dropping 6-800 rpm below quoted rpm figures.

If memory serves me correctly, before Toledo last year Dave J. quoted 6800-6900 from a prototype DA50 they had just put together, again with a 22-10 (can't remember which prop maker). This is about what a new, non-broken in BME-50 (current 50) turns with the Menz-s 22-10, and most of the "other" guys are getting in the 6800-7200 range for engines like the Taurus, Brison, and other engines in the 50-55cc size class. So, it seems that the low 7000's is the norm for most of these engines (depending on prop). Compare that to the prototype 55cc BME that was quoted to be substantially stronger, in the 7600-7800 (7800 reported after 10 minute run-in and warm-up, with a Mejzlik 22-10), and you can make your own conclusions.

There is really no telling when the BME55 wil hit the production line. Keith is burning a lot of midnight oil coordinating the effort to get the design finalized and this motor produced. Time will tell, so they say, but if preliminary power and weight numbers are any indication, the BME55 will come in under the 2 lbs target, and produce substantially more power than comparable sized motors.

Your best bet would be to either email or call BME for keiths direct reply.

rmh

This new engine sounds interesting and given that it all turns out as hoped for - should work well in planes as light as 11 lbs.
I have been fly 11 lb 1280 sq in planes (2) since August -with 40 cc (not BME) gasser- and the vibration has caused NO problems - Only detectable wear is in linkages and a tiny bit of gear train slop on the JR 811 servos -one per aileron.
3 blade 19x11 Mejzlic runs over 7000 rpm easily .
I do run a 20x10 prop usually - as it is good enough .
The performance with power to weight in this range is totally unlike the 15 lb stuff- you should enjoy it.
the combo of a 3 lb engine and a 5 lb airframe is not impractical. Any good builder can do it - No carbon fibre needed .

EJB

Hey Dick,Is that a typo?A 5 lb airframe with an 80" wingspan?

rcpilot44

My Feedback: (1)

Thanks Kris,
I pre-ordered a BME 55 this morning. I hope it is not delayed and I hope the numbers truly come out as he has stated. As you can see from my picture above, my plane is ready for an engine. If I hear it will be delayed again I Will probably get a DA 50. I would like to hear from pilots who are flying with a DA 50..

Kris^

My Feedback: (1)

cmon, dick, You can mention the name ZDZ in this forum. No one is gonna bite your head off for it.

Really, with the lightweight, yet very powerful, engines that the manufacturers are supplying for us, we now have several options for every combination. sound like a win win win situation to me.

Now, if they would only lower the price of GAS!!!!!

rmh

5 lb airframe is not a misprint.
If you really want to get spectacular performance -- you start with the airframe -- not carbon fibre gear, etc.
The weight of the airframe - to get an 11 lb finished model ---using a 3 lb engine -- is about 5 lbs.
then when you have a good solid 5 lb airframe - , add 4 lbs for "the power plant".
now we are at 9 lbs - which leaves 2 -for covering and radio
The real key is to get the fuselage weight down -using spruce longerons to carry the load - then all else is balsa strips or sheet
No motorboxes - they are dead weight -
gear - 3/16" wire is stil the lightest and strongest and most forgiving.
wings and tail group are simple solid 1 lb foam and 6 lb ,1/16 balsa .
entire ready to go wings inc servos - under 30 ozs- .
You can do it - and it is really quick and easy to do - just do not copy any ARF construction .
I will print a pic of one of my models - 2mx2m done just as mentioned - using 40 RE and a tuned pipe