I'm replacing an OS 1.60 w 18x6W APC prop combination n a 13-14 lbs plane (not enough power) I'd like to hear back form people who have run the BME-44, what props they used and the weight of the planes the engine was used on. This is a 3D-style plane, and I'm trying to keep it as light as possible while at the same time having sufficient thrust to pull out of a TR with good authority.

Thanks in advance.

Hi Kris,
I have the 44 on a 15lbs TBM staudacher 78" model. I use NX 20-8 and it is way more than it needs. I tried a 20-10 and it was too fast for me.
HTH

Joe

Thanks Goekeli .. I have the 44 sitting on the shelf here, but have never played with one. I was going to go with a Menz-s 20-8 or 20-7 for hovering and low speed grunt. Don't need speed for this plane, just need good acceleration and hovering ability and some ability to overcome the very drggy airframe.

Kris^,

I also have one on a 15lbs. aerobat and use a Menz 20x8. The 20x10 was too fast for me also. It has plenty of power, I really like it!

Tim

I've just done a weight comparison, the OS1.60, complete with muffler, is 2 lbs 14 ounces, the BME44, bare, is 2-11. Trying REALLY hard to not add weight, I can use a 5 ounce battery, 4 ounce ignition, move the tank to the CG, and gain 8 ounces, total weight. After that, it will be the weight of the exhaust system that ruins my day. A canister setup is 12-13 ounces (ouch).

Any suggestions on exhaust?

Kris,
I use the stock banjo muffler from BME. It is louder than a pitts but is light. Do you need it to be real quite? I weighted my 44 with everything needed to run including nylon/glass mounts shaved down to the max but without prop or spinner and it way 3lbs and 14 oz. Very close to 4 pounds and that was on a postal scale. The battery is a 1000 mah sanyo nicad. How many square inches is your models wing area? My igntion battery is back on the CG btw.

Joe !~)

Just flew my AW profile extra with the BME 44 and BME 21 x 8 prop turning 6900, 12.8 lbs. Stock muffler is really light. Runs great, couple of flips pop and one flip to start.

fly3dnyc,
Nice plane!!!!!. That must be a lot of fun?

JOe !~)

Well. . I may as well let the secret out. .

This is a prototype 80" Funfly, using full-flying tail surfaces and STOOPID wing area. Span is 80", average chord is 26.5, weight witht he OS1.60 was right at 13.5 dry, and I'm really trying hard to keep the weight with the BME under 14.5. The fuselage has ain internal tunnel for canisters, so I've looked it over and decided to used a header-exhaust pipe system that lopps around the cylinder head and then into this tunnel, splitting into two stingers and out the back/bottom of the tunnels exit. I figure it will have aobut hte same sound signature as a standard "banjo" or pitts style muffler, since it's a long tube with a lot of expansion area.

Details about the airframe are:

We call it a "Frenzy" can't imagine why. . . .

Split ailerons using 8411's (going to the heavier duty Futaba 9153's for more throw)
joined flying stabilators using 2 8411's
full flying dorsal/ventral rudder powered by a single 5735 HiTec (Might get changed to a Futaba9153 to save some weight)

Wing area is 2120 sq-in. Wing loading is right at 14.5 ounces/ft.

Flight characteristics? Even nose heavy it will do a hovering waterfall, and will waterfall in both directions. Walls, parachutes, square loops all exhibit a tendency to throw the tail out in front of the pull, even though it's nose heavy, which means it MAY be able to do a "Cobra" when I get it dialed in, will fly right into a hovering flat spin, just slam the rudder over and hold in a little opposite aileron and up elevator and it sits there and spins. I tried to flutter the surfaces. . luckily they didn't cooperate. Roll rate is about 2-2.5 rolls/second, and should improve with stronger servos.

All it needs is to move the wing forward about 1.5-2" (change CG), get the stronger servos on the ailerons, and more power.

Kris^,

Did you ever get that special ignition from BME for your 110X? The one that had the programed timing curve that was supposed to make the low end smoother?

How is the overall vibration/pulse levels of that engine compared to say a DA100 or ZDZ 80?

Skypilot, I've been using the ignitions that came with my engines, no modifications or "special" curves to them. BME is, however, looking into upgrading the ignition or making changes to it sometime in the future, though that may not happen as well. For right now, though, I can honestly say that there appears to be no changes necessary. All 3 of my "Xtreme" based engines (2-110's and a 106) have smooth idles after you get the carburetor set properly, and there is no noticeable "vibration" throughout the rpm range of the engine. I idle them down to 1000-1100 rpm with ease, and the planes do not buck or rattle even at that low rpm, though going lower can make things get a bit rough unless you are very keen on the low end mixture. I can't see a reason to idle below 1200 rpm, but a decently smooth, and dependable, idle is very easy to achieve as low as 900 rpm, should you desire. A lot of the problems people experience with idle quality are directly related to the quality of gas and the low-end mixture being set too rich, so that the fuel puddles or drops out of suspension and does not burn properly, resulting int a rough idle.

As for how the engine "pulses" compared to the DA100 or ZDZ80. . again, a lot of that goes back to tuning of the carburetor. The porting on the DA100 is condusive to very smooth low-end operation and mid-range, and the ZDZ-80 doesn't have a problem idling, that I've seen, though the 80 does come into a harmonic imbalance at about 2500-3500 rpm, which is normal for a single cylinder engine. If you botch the mixture on any of these engines, they are going to let you know about it with a rough idle and other things going on. Best bet is to learn to tweak those needles, and address any problems as they crop up.

Hope this helps.

Kris,
Nice plane! Looks like it will get extremely sic with all that control surface. Are you going to get it into a kit?

Joe

Talking to a couple of people about an ARC/ARF, Geokeli. . after I get it all dialed in then we'll make a "production" prototype and smooth out the assembly and structure. Need to drop the weight a bit, and simplify the structure/setup a tad as well. I'd really like to see 12.5 lbs, and a smaller wing with a different aileron setup for more throw and power from the surfaces. The end desire is to have every control surface a "Flying surface" instead of just hanging back there flapping like a barn door.

I've decided on a 20-8 Menz for the BME44, thanks for the inputs guys. Now, if I can find one

Kris^,

Thank you for the off topic reply. I think you did answer my questions.

Your plane looks like it will be fun!