Ramz

What engine is better? A BME 105 or a Desert Aircraft 100? How do they compare weightwise and powerwise? I've got a 35% Diablo (97" wingspan) and i'm wondering what type of engine to put on it. I know a guy that has a BME 105 and it is a beautiful, awesome working engine although i have never seen a DA100 working. The plane should weight about 20 lbs when it's ready to fly. I want to hover at 1/2 throttle. Thanks.

Tim_Indy

The DA 100 will make a bit more power than the BME 105 (couple hundred rpm on the same prop) but the BME will weigh almost 1.5 pounds less.

Actually, though, if your plane ends up weighing even 24 pounds or less, either engine will hover it at 1/3 throttle.

Kris^

My Feedback: (1)

Ramz, the DA100 will add an additional 1.2-1.5 lbs to t he nose of your very lightweight plane. This will require a lot of additional tailweight to keep it form being nose heavy. When you start hanging a lot of weight at the ends of a planes fuselage, it makes the plane less responsive, and also makes theplane tend to over-rotate coming out of tight maneuvers such as snaps. The best bet is to keep the plane as light as possible, while still having ample power for it.

When comparing the DA100 and the BME105, several things are apparent. First off, the BME is much lighter. Secondly, when comparing rpm numbers, the BME is not substantially down on power compared to the DA, usually on the order of about 100 rpm or so. Third, you are looking at a BME105.. NOT the 102. . . after you get the engine, a simple payment to BME will get you a pair of pistons, cylinders, and associated pieces, to upgrade the engine to the BME 110cc "XTREME" status, and THAT, my friend, is a whole nuther ball game!!! All that's left is getting the proper plug caps to fit the CM-6 plugs on the 110, and you are flying with the most power, AND lightest, "100cc" class engine on the market!!

now . .knowing all that. . why even consider the DA? Get the 105 and upgrade it. . then be done with it.

JohnVH

My Feedback: (38)

Get the DA, less shake, more power, your plane will balance fine.

Kris^

My Feedback: (1)

Get the BME .WHAT shake, MOST power, and your plane will balance BETTER.

JohnVH

My Feedback: (38)

****


Ramz, if your buddies fly BME, then go that way, BUT, look at TOC flyers, hmm, mostly DA, not BME. Kris^, havent you made enough commision for that thing yet.

Kris^

My Feedback: (1)

(chuckle) John, I'm still payin off the ADVANCE.

Just kidding of course. . .

Gotta remember though, John, the smallest engines in the TOC were 150cc's in the last few events. . a bit larger than the BME110 and certainly an "Apples vs oranges" comparison. Now, if the TOC guys had only the BME110, DA100 and 3W106 to choose from. .which do you think they would have preferred? Be honest now. . . sponsorships aside, those guys will kill for an extra pound out of their airframes, and saving 2 lbs is like the 2nd coming for them. Given the extra power now associated with the known output of the BME110, as well as it's definite weight savings, I'd venture that the engine of choice would be the BME110 if the TOC guys had only these three engines to choose from. Then again, sponsorship dollars are a big consideration for "named" pilots, unlike the rest of us who pay full dollar for our equipment.

But, I guess we'll never know, will we?

JohnVH

My Feedback: (38)

Honestly, they would chose the DA100. Come on over to the IMAC meets, one BME 102, one 3W, wich died in a harrier BTW, and EVERY other plane has a DA100 in it. Just stating what is here. Im sure you will say its the opposite in your corner of the world, but hey, these guys can all buy a 110, do they? nope. BUT, this thread was not about the 110, maybe someday when its as proven as a DA it will catch on, until then, DA for me thanks.

0tter

My Feedback: (39)

cant get a BME 110 any way. Better get in line quick!

augiep38

My Feedback: (3)

Has BME changed the prop shaft size on the 110 to 10mm yet so that you can bolt on props without reaming them? If not, I would definately not consider it.

I have the BME 102EVO and that is my main gripe. I have to ream out the prop hole.

I also like the 6 bolt hubs on my DA and 3w's.

Todd

lsnover

My Feedback: (19)

I don't own either of these engines.

Presently I have a Brison 6.4 (108). It's a great motor, but not in "voque" with the "in crowd" these days.

On the IMAC list I've heard great things about both BME and DA. The only negative I've heard is that BME is slow on service and DA is exceptional, so that may be an issue to consider.

My personal experience with ZDZ is that they can be slow on getting parts as well, but they offer great "bang for the buck". I have a friend I fly with with an 80 and a 200. He had to wait months to get the 80 repaired and is now waiting many weeks on a 200 repair for his H9 Ultimate.

Waiting stinks when you want to fly, so I would inquire with any potential vendor as to what you can expect when it's time for service.

Diablo-RCU

My Feedback: (1)

I second Todd's opinion. BME should use the 10mm prop stud and 6-bolt pattern that DA, 3W and ZDZ use. The small weight gain would not be significant to me. At least make it optional.

JDM

My Feedback: (8)

For what it's worth. I too have been trying to decide BME, DA 0r 3W. From all the reading and search on RCU, I have decided that DA is the way to go. Primary reason is Customer service. I have heard nothing but great things about Dave and his staff at DA. Turn around time is short, and work is always great. They even respond to e-mail. BME on the other hand, well lets just say that from what I've read, they are lacking in the Customer service arena. As is Cactus and Aircraft Intl.(3W) I can only say that if customer service is impotant to you, then based on all that I have read, DA is the only way. Just my 2 cents.

JB Rekit

My Feedback: (3)

Aside from customer service, the main reason I would go with DA especially on a light plane like that is that Kris said in another thread that the 110 has "TOO MUCH" power for his 25 or so pound plane b/c the 110 doesn't have good throttle pesponse down low. It will immediatly jump to 4000 rpm with the high angled valve job on it. If you have to fly it around at full throttle all the time, it will have too much power for your plane, the DA would also, but at least you will have a smooth linear throttle curve that you can fly in.

Just my $.02

Tim_Indy

High angled VALVE JOB? Well, guess THAT'S an informed response, especially since two stroke engines (like the BME) don't have valves in the first place.

Tim_Indy

JB Rekit, I haven't seen ANYWHERE that Kris^ said that the BME 110 didn't have good throttle response. Matter of fact, if you'll refer to the BME vs DA thread's post #14 located [link=http://www.rcuniverse.com/forum/fb.asp?m=1155568&key=]HERE[/link], you'll see that he satated that the DA had the smoothest idle and smoothest transition, that the 3W 106 had a slightly rougher idle and more tendency to burble in misrange, but a stronger top end than the DA. More importantly to this note, he said the BME 110 "exhibits idle/midrange characteristics close to the DA, but is just as powerful (if not more so) than the 3W 106" .

Even more important is that I DO have a bME 110, and have zero issues with it's idle transition, and mid-range characteristics (not to mention the POWER!!).

Needs to run at high throttle all the time? Hardly!

Kris^

My Feedback: (1)

JB, either I mis-stated what I meant or you misinterpretted it.

Being that I prefer a very aggressive low-throttle speed increase as I open the throttle, I have programmed curves in my radios to ensure that at 4 clicks the engine is at least 1/3 throttle already. This is my own personal setup. HOWEVER, if I did not put a point mix on the throttle of my 110, it would be what I consider to be too slow. Some people like a slowly progressing low-mid throttle sensitivity. I don't. . I want it NOW, not when the stick gets to the half throttle position, because I seldom use anything below 1/4 throttle in sequence flying, unless its completely off-throttle idle.

That being said, on my 40% plane with the 110, I had a rather soft lower throttle curve in the plane last weekend, because I changed transmitters and had not reprogrammed the curve. Another person flying the plane said it lacked low-throttle power progression, and asked if I had softened it up. It was kind of embarassing to tell him it was the first flight since I changed transmitters, even though the rud-ele mix, rates, and expo were almost dead on. We were having to use about half throttle where both of us were used to 1/4 throttle for the same power settings.

Well. . .I took the hint and added an aggressive low-throttle curve in again, and the engine responds quickly, the way I like it.

Now, on the 33% its a bit of a different story, since the plane likes to "carry" at low throttle, due to momentum and inertia, so you have to have a really agressive throttle "chop" on the last 1/4 of the stick to ensure the power comes off quickly. Being that it also comes into the power quickly fits my style of flying, so when i say it's too much for the palne at half throttle, I'm telling the truth. 1/2 stick is about 3/4 throttle for me. . you can see where the over-powered low-mid-range settings could be a slight nuisance with a very powerful engien on a small airframe. . I'm sure that if I took the aggressive throttle curve out of the transmitter it would have a very "linear" power progression for those who liked it that way.

The only other thing I can say is that the 110 is definitely WAY more power than you need for a 33-35% plane. . BUT, if you like 60mph vertical lines, be my guest. . though IMHO it looks rather silly.

EJB

Yep,and it's silly to even consider a 100 twin for a 97",20 lb.plane.
A ZDZ 80 single WILL EASILY hover a 20 lb.plane at 1/3 throttle....at half the price.

Kris^

My Feedback: (1)

No argument here. . .I almost advised the exact same thing.

blkbird68

My Feedback: (19)

oh really??? I have emailed DA about a dozen times this year and have yet to get a single response....I have also not been able to reach them by phone the couple times I tried calling....I finally gave up on bought stuff elsewhere...Although I must say that I haven't heard a major complaint about DA's service.

True, BME is running into problems getting 110's out at the rate they want...but Keith has always answered my emails and so far every time I have called he answered the phone. So I'll wait for my 110 for several reasons. 1) the weight 2)it will fit in the cowl without having to do any cutting 3)of the BME's and DA's that I have seen, the BME's ran more consistent, and haven't had to go back for repairs other than crash damage, can't say the same for the DA's...and around here there are more BME's than DA's.

JB Rekit

My Feedback: (3)

No they do not have valves that move up and down like a four stroke, but there are still valves on a two stroke, a ZDZ has a rotary valve, then there are reed valves, etc. The size and angle, have to do with the low, mid and high range performance of the engine, it is not the only thing but it does play a part, as well as the compression, header, exhaust, that all make a difference.

http://www.rcshowcase.com/html/faq.html#valve

JB Rekit

My Feedback: (3)

Here is a link for people if they are interested that shows the inside of a two stroke motor.

http://www.rcshowcase.com/html/engines/zdzinsides.html

I think a few people are unaware of a few crucial parts that make it work

Kris^

My Feedback: (1)

Well.. that's what's inside a ZDZ 2-stroke.. but not what's inside a BME. . .

BME has a hidden super-efficient supercharger nestled between the cyinders that actually makes the engine lighter due to the increased airflow and adds 50% more power than any other design . . . .. it's MAGIC. .right??

JB Rekit

My Feedback: (3)

Kris

What prop are you using on your 40%?
I remember you talking about a 28 or 29x10 mejzlik but wasn't sure what you ended up with and was also wondering about the final weight.

I am building the AW 39% 330L right now and it is a fairly light kit (not like the fiberclassics) but about a pound or two lighter than the Carden and was wondering what else you did to yours to keep the weight down and if you hit your 29 lb. mark.

I am putting in LIon batteries, carbon gear/spinner/tailwheel, 4 oz tires, etc.

Mark told me I might be interested in the new JR 9411 servo that is standard size and weight but has 300 oz of tq and I could use one per elevator and 3 on the rudder which would save about a pound right there.

I have the DA 150 and the KS 90 cc cans so I can already add about 4 lbs to whatever you came out with plus another 2 pounds on the kit but if I come out at around 35#'s I would be very happy.

Just wondering if you found some new areas to lose some weight on the plane.

John

Kris^

My Feedback: (1)

Actually, a DA150 on canisters, with prop and spinner, is about 13 lbs, JB. . my BME, similarly set up, is about 7, so start off thinking 6 lbs heavier, which is about right considering that Jasons 40% with DA/canisters and the same layup of the airframe came in at 34.5 lbs at the last TOC and mine with the BME is 28.5.

I finally setlled back on the Biela or menz-s 28-10, or the mejzlik 29-10, for my plane, JB. the 28-10 mejzlik was just too noisey and spun too fast to be practical.

The best and fastest way to lose weight is with a CF wingtube. . i save 12 ounces on mine by doing that. otherwise. . lots of attention to details and do not add anything that is not necessary. A pilot and IP makes my plane 29 lbs even, so it's 28 lbs 8 ounces with 10 servos, receiver, 3 battery packs, no wheel pants, 32 ounce tank, BME/Canisters prop and spinner and about 1.5 lbs of paint and graphics.

I'm actually wanting to sell the other 40% I have that has a 3w150TOC/canisters on it, so that I can build another ultra-light plane. Asking 3750 without radio gear and it comes with one of the MC40-24 electronic voltage controllers.