busted blade

What kind of rpm are you getting with the 16x8? I have tried 16x8, 17x6, 17x8 and cant seem to get much over 6500 out of it. doesnt seem to matter what kind of adjustments I do.

What is a good rpm reading for the 26cc engine, I am thinking that 6500 seems a bit low. Was hoping to get around 7500 out of it.

linkadrip

I'm running a Vess 16X8 prop and my max rpm so far has been 8322 rpm thats the fastest reading i have had, but it depends alot on the type of prop used. I have a Zinger pro i put on it, the same size 16X8 and it will only max out to 7235 rpm. I think the desighn of the prop makes a big difference maybe it's type of wood and mass of the prop. the vess will actually flex at the tips. I had one of the vess props shatter at both the tips at 8000 rpm that was scary. Starting making a howling noise.

Making sure your prop is balanced is a very key thing too. if the prop is not balance the rpm won't be as high. I balance the hub and tips i spend alot of time balancing the propeller for minimual vibration.

Fuel i'm running in it is 92 octane and mixed with mobile 1 racing oil. dont know if the fuel i'm using makes a difference but it might. I'm mixing it 40:1.

If the engine is New and your running it in. i wouldn't try to get a high rpm out of it. i didnt start getting the higher rpm till i switched fuel to 92 octane and started mixing 40:1.

During break in i was mixing 30:1 and running a lower octane fuel and only run it out to about 6000 rpm for short periods. It will get better as it gets run in, easier to start and will transition smoother and faster unless its already run in then i dont know.

Looking at the vesss prop comapred to the Zinger prop the vess is a thinner prop near the ends and thicker in toward the Center hub the zinger is thick through out the prop with a smaller hub area. The vess prop as rpm increases it tends to flex and that is probably why the higher rpm, but the thrust from the vess doesn't seem to be as much a the zinger.

I havent tried any plastic APC or MAS props And dont think they would be safe to run on a gas engine not sure never done it. but there are those brands in wood i might try. I know that a MAS glass filled prop flexes, I have one my os 61 and you can see it flex. Try different props and a differnt fuel combinations is the only thing i can recomend a person do. I actually wasn't trying to reach any set goal for rpm. I was just messing around and got the reading i got, as long as it pulls the plane through the air i'll be happy.

I haven't tried differnt sizeprops on it. I might when i get bigger wheels for the plane. I think an 18x6 on my Twist 150 would probably hit the ground.

busted blade

Thanks for the info... I guess I need to run it a little more and see what happens.

since everyone seems to be getting close to or over 8000rpm it made me wonder what I was doing wrong.

Patto

All props are going to flex to some extent. If they didn't flex, they would break. All airplane wings flex as well. Ever look out the wing when you're flying on a 737? Yikes! Looks like they're going to break!!

I've used the Master Airscrew 16X8 on the BCMA 26, and it did okay. I have also used the Xoar 18X6 with very good results. In fact, I think that ended up being my preference for IMAC and 3D flying. However, using the APC 16X4W, I was able to turn almost 9000 RPM, which made the power range a little wider, which I liked for hovering.

Adam said that 9000 is about the max RPM you want to run. Also, it is not bad to have higher RPM's for break-in. Quite contrary, in fact. Adam has said before that loading with too much prop can in fact hinder the break-in process.

kruzin55

Just wanted to post a recommendation for BCMA engines. I had trouble getting my SPE 26cc gasser to run reliably. I was convinced that the Walbro carb was the culprit, but after a rebuild, it still would not start. Called BCMA and they were quite helpful and suggested that many ignition issues are misdiagnosed as carb problems. Ordered the new ignition and it arrive today. Engine started right away and ran reliably on several starts. Thanks for the help.

linkadrip

I was not aware of this I Was thinking Too high an rpm may cause excessive wearing of the engine, from higher temperatures.
If i were rich i would buy another engine and due extreme test on the engine. I'm kinda curious at what rpm the engine would fail. But thats about it just curious.

Probably would be pointless, No One is going to fly there Plane at 10000 rpm for a long period of time. Unless there's some kind of pylon racing plane the engine would fit in. that would be a pretty good size racing plane. Would be intresting to see a tuned pipe on one of these engines.

Bet it would be real loud.[sm=what_smile.gif]

Al Lewis

When we broke in our first BCMA 26 we did it with a APC 16X4W and ran 9000 rpm in a Showtime. Since the break in we have switched it to a Xoar 18X6 and then a Mezlik 18X6 in the 25% Pitts S2B and it runs great on that prop. One other point, I keep hearing people referring to their SPE 26cc engines. These are not going to run the same numbers as a BCMA engine in most cases. They have been historically lower.

http://media.putfile.com/BCMA-26cc-Break-In--Maiden

I B BUCK

Shane that is for the 26.
Buck

linkadrip

Well the engine i have was purchased from BCMA engine's but SPE is stamped on the engine. If the engine were manufactured buy BCMA shouldnt it be stamped BCMA on the engine. I have no idea what SPE stands for i would imagine it is the abreviation for the company that manufactures the engine. And BCMA just purchases the engine from this manufacture and sells them.

I notice the engine in the video has a Velocity Stack on it. I should purchase one for my engine then i could probably get some higher rpms out of mine. i'm sure it makes a difference in the way the engine runs. Great looking plane.

I like the Rpm meter from hobbico, need to get on like that. I have a hangar 9 meter and you have to multiply the reading times 10 to figure out what the rpm is. looks like the hobbico one gives you the reading outright witch is alot handier.

Well wish everyone the best with there engine's try different things and experiment a little to find out what works best. Mine seems to be running good with a Zinger 16X8 on it. Think i will get the velocity stack that adam sells for the engines. Then that's about it go fly and have fun.

Flyer Freq

I am not sure of what all Adam does to them at this point, but I can tell you that the ignition is a huge upgrade from the SPE ignition. The ignition alone is worth buying the BCMA SPE engines.

Pit-Viper 1

My Feedback: (12)

I just read a very interesting article in the new Model Aviation magazine (Jan'08 issue pg.65) about oil types and breaking in gas motors. They say to never go over 4000 rpm in any gas motor during break in as it will cause excessive heat that will cause extreme or uneven wear. It also states to never add more oil to the mixture than what is called for, it says it can cause variations in timing, stuck rings, excessive carbon in the combustion chamber and exhaust ports and preignition. It is a very interesting article.

I am new to gassers and think that all the information on here is reasonable, not trying to poke at anyones opinion. Just sharing info.

What kind of results have those of you that have tried the Bowmans ring had? Have you done a before and after trial with it to see the difference? Got one on order from Adam and will try it after it arrives. Also, will I need to re-run-in the new ring since the motor is almost broke-in now?

Thanks,
Shane

karolh

Yes you will have to break in the new ring, just like you did when the engine was new.

Karol

Al Lewis

I'm in the process of breaking one in on a 3MM 53cc. So far it seems stronger and runs cooler. I'll let you know how it goes.

karolh

I have no experience with how a Bowman ring performs in a gasser but can say that one made a world of difference in my glow ST G90.

Karol

paul nathalie

[link=http://h]http://www.rcuniverse.com/item/m5s8gnk248fjpvmh [/link] small vid of my 26.

paul nathalie

try again. [link=http://h]http://www.rcuvideos.com/item/m5s8gnk248fjpvmh [/link]

shaneandmargy

Hi guys, I recieved my engine from Adam here in Australia and let me say the 70 inch Extra he sells now coupled with the BCMA 26 is such a fantastic combination if you are new to gassers. I have about 40 mins run time on the 26 and it's swinging a Bolly 17x6 prop at around 7300 rpm. This plane is the easiest thing to fly and with the 17x6 prop it is a gem to fly. I've only had 4 flights and I can't wait to get some more time on the Extra and try some 3-D stuff. This is one sweet plane/engine combination. If you are after your first gasser, get this combo, you will not be dissappointed. Adam, thanks for the great products you sell and it has been a pleasure dealing with you all the way here in Oz.

Shane

paul nathalie

Hi, can any body tell me how to post a video correctly here?

Al Lewis

Sure, first you sign up for a free account at www.putfile.com Then you upload the video to there. When it finishes uploading you will have three lines or listings. Click the "COPY" button on the right of the top one. Then come over here and paste that link you copied onto you post. It will look just like this one but with a different name.

http://media.putfile.com/BCMA-40cc-Maiden-Flight

linkadrip

Well lou all your other videos seem to work can't seem to get that one there to load but thats ok no bigge.

Al Lewis

Yeah, They seem to be having problems with a few of them. One day they all come up, other days just a few. I think they may be re-formatting them. Normally they are very good though and you can upload up to 200megs per video with unlimited videos. There, I changed it to the BCMA 40cc maiden. That ones already been converted.

Flyer Freq

Hey Shane! What was the all up weight of this combination???

Andy

shaneandmargy

Hey Andy, the weight was around 4 kg (9 lbs). If you want a fun, 3-D plane this thing is a great combination.

Cheers, Shane

Flyer Freq

9Lbs! Cool!!! It is a sweet looking bird! Any pics of yours?
Andy

shaneandmargy

Not yet. I have to get them on the computer. Adam said he'd like some as well. My Extra is the same as Adam sells but in a different colour scheme (red,white and silver). My mate Steve has the Edge 540 which his BCMA 26 is going in.