RE: BME 115 Any Field Reports?  
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RE: BME 115 Any Fie... - 10/3/2007 11:30:50 PM   
RTK


 

Posts: 4089
Joined: 4/20/2003
From: CENTRAL , CA, USA
Status: offline 		Good reason not to be in a hurry and fly alone Since I won't have time to fly for a while I wanted to at least see if it would work.

(in reply to Tired Old Man)
       Post #: 851

RE: BME 115 Any Fie... - 10/4/2007 1:13:19 AM   
altavillan


 

Posts: 1236
Joined: 10/24/2004
From: Altaville, CA, USA
Status: offline 		Fantastic, And since you are gona be gone for a bit drop the carb off here on your way through

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(in reply to RTK)
       Post #: 852

RE: BME 115 Any Fie... - 10/4/2007 1:23:01 AM   
RTK


 

Posts: 4089
Joined: 4/20/2003
From: CENTRAL , CA, USA
Status: offline 		If I had time I would be more than happy to altavillin
Gonna test another carb when I receive it as per my request. This new one will have the high needle linked to the throttle arm, similar to the MVVS 116. Hardened needle and insert to stop wear.

(in reply to altavillan)
       Post #: 853

RE: BME 115 Any Fie... - 10/4/2007 1:06:32 PM   
Wings-RCU



Posts: 696
Joined: 1/5/2002
From: Green Bay, WI, USA
Status: offline 		RTK is this a modified WB? Does it have the same venturi size as the WB?
please try this:
Low throttle (less that 1/4) roll to knife edge with the rear cylinder pointing down, or better yet, run the engine on the ground less the 1/4 throttle and rotate the plane with the rear cylinder down. Does it loose several hundred RPM? Did you try slow rolling circles at a low throttle setting? After several carb mods my engine also runs as you describe but still has the nasty habit of sagging in a low throttle knife edge. It still responds well to the throttle when it sags but this makes for some difficult flying.

(in reply to RTK)
       Post #: 854

RE: BME 115 Any Fie... - 10/4/2007 3:21:16 PM   
altavillan


 

Posts: 1236
Joined: 10/24/2004
From: Altaville, CA, USA
Status: offline 		Wings I know it's probably mentioned before but if you are having a low rpm sag when rolling to KE that would indicate the low needle is a bit fat. What you are doing is positioning the fuel storage bowl in a position higher than the needles and that allows the engine to draw more fuel. At 1/4 throttle the engine is responding to the low needle setting and not much to the high. The carb is massively large and air currents through it are minamul for operation. A tiny adjustment to lean the low might fix it.

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I didn''t put the bullet in the fire and you quit talking about my mother! "Cosby, Shop Class, 1968 or so"

(in reply to Wings-RCU)
       Post #: 855

RE: BME 115 Any Fie... - 10/4/2007 4:53:21 PM   
RTK


 

Posts: 4089
Joined: 4/20/2003
From: CENTRAL , CA, USA
Status: offline
quote:

ORIGINAL: Wings-RCU

RTK is this a modified WB? Does it have the same venturi size as the WB?
please try this:
Low throttle (less that 1/4) roll to knife edge with the rear cylinder pointing down, or better yet, run the engine on the ground less the 1/4 throttle and rotate the plane with the rear cylinder down. Does it loose several hundred RPM? Did you try slow rolling circles at a low throttle setting? After several carb mods my engine also runs as you describe but still has the nasty habit of sagging in a low throttle knife edge. It still responds well to the throttle when it sags but this makes for some difficult flying.


I was in a bit of a hurry, but I rolled (slow) and KE'd the plane at every throttle setting from idle to WOT.

(in reply to Wings-RCU)
       Post #: 856

RE: BME 115 Any Fie... - 10/4/2007 6:13:52 PM   
dbcaster


 

Posts: 333
Joined: 7/1/2006
From: Petaluma, CA, USA
Status: offline 		What wings is decribing is the main issue. If you lean the low enough to get rid of the rpm drop the engine will flame out. There is no middle ground. At least I never found it, and that is with the smallest amount of mixture changes possible. The problem happens on the ground as well if you pick up the plane and turn it on knife edge so it can't be an airflow issue.
Wings,
I was in your same position, trying to dial in rolling circles and dealing with rpm drops is no fun.

(in reply to RTK)
       Post #: 857

RE: BME 115 Any Fie... - 10/4/2007 6:30:21 PM   
RTK


 

Posts: 4089
Joined: 4/20/2003
From: CENTRAL , CA, USA
Status: offline
quote:

ORIGINAL: dbcaster

What wings is decribing is the main issue. If you lean the low enough to get rid of the rpm drop the engine will flame out. There is no middle ground. At least I never found it, and that is with the smallest amount of mixture changes possible. The problem happens on the ground as well if you pick up the plane and turn it on knife edge so it can't be an airflow issue.
Wings,
I was in your same position, trying to dial in rolling circles and dealing with rpm drops is no fun.


dbcaster---That is why I told everyone in MULTIPLE posts to NOT adjust the needles as you would with other engines. The low does not affect the low/mid range to that great of an extent, it is the high coming in to soon causing the richening.
Why don't you call or e-mail the manufacturer and ask him for yourself?? Because if you would have he would have told you exactly what I am saying. So either you have not contacted him and or never listened to me or..............

Next time try BMEENGINE@aol.com

Sorry for the poor attitude, bad day at work.

(in reply to dbcaster)
       Post #: 858

RE: BME 115 Any Fie... - 10/4/2007 6:53:26 PM   
Hammbone



Posts: 1437
Joined: 1/5/2002
From: Fort Collins, CO, USA
Status: offline 		Part of the problem is that at first everyone, including Keith, was saying to get both the low and high ends as lean as possible. Keith told me to do this.
It wasn't until later that Keith and others realized that it was better to have the low end a little rich, and the high end a little lean. Now most agree that this is what's best. Unfortunately, it's still not good enough and we are still looking for a solution to the rich mid range.

Jim

(in reply to RTK)
       Post #: 859

RE: BME 115 Any Fie... - 10/4/2007 9:29:43 PM   
altavillan


 

Posts: 1236
Joined: 10/24/2004
From: Altaville, CA, USA
Status: offline 		Ok then my bad. Since it is getting too much fuel in KE, open em up some more. Scratching head.

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I didn''t put the bullet in the fire and you quit talking about my mother! "Cosby, Shop Class, 1968 or so"

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       Post #: 860

RE: BME 115 Any Fie... - 10/4/2007 9:30:52 PM   
Tired Old Man


 

Posts: 12356
Joined: 2/25/2002
From: Central, CA, USA
Status: online 		Seems there are now 3 ways to skin this cat. One is patrickP's mysterious carb add on. One is the new 3 needle carb from BME. It had BETTER work perfectly. The last is using a smaller carb like the one Altavillan has been playing with.

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If you can''t fix it with a hammer, you have an electrical problem.

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RE: BME 115 Any Fie... - 10/4/2007 10:41:28 PM   
RTK


 

Posts: 4089
Joined: 4/20/2003
From: CENTRAL , CA, USA
Status: offline 		Pat- I only have a few flights on mine, I'm not jumping the gun yet. But it did work the first time out. There might also be a forth way soon.

Altivillan-- You can turn up the low needle a lot and it will not muddy up the low/mid range causing the dreaded burble when rolling. The problem is the high circuit is feeding WAY too soon. That is what is screwing up the low/mid range, lean the high enough and it subsides. Or at least for me, but if you fly much WOT it gets hot quick! and you know me.
So,,,,, You richen the low needle to compensate for the leaning of the high which keeps you from melting your canister couplers. Well, it still will lean on the top with out a mod.

Counter intuitive, ain't it

I haven't counted the turns on the three needle carb yet. All you really have to do is visually see how the low is cranked out and the high (now mid) is turned almost all the way in. The new high is the old governor.
That is what I like about the three needle carb. It "should" be infinitely adjustable for any engine made.

Edited for dbcaster--You are correct, with the "stock" WB carb you will either be too lean on the top and ok in the low/mid OR you will be rich/dieing in the low/mid and fine on the high.


< Message edited by RTK -- 10/4/2007 11:54:51 PM >

(in reply to altavillan)
       Post #: 862

RE: BME 115 Any Fie... - 10/4/2007 11:36:37 PM   
dbcaster


 

Posts: 333
Joined: 7/1/2006
From: Petaluma, CA, USA
Status: offline 		RTK,
I did call Keith several times on this issue. I was going to write a response but this BS is why I left this thread in the first place. You always put it back on the user. There is a design issue with the porting and case on the engine in MY opinion. You can keep saying 98% of the people out there don't know how to tune a carb all day. If the engine is only usable by the 2% that are carb tuning experts or want to search for a better carb on a $1200 engine so be it. I knew I should not have come back to this thread and I will not again. Good luck to all with the wonderful adventure of the BME 115.

(in reply to RTK)
       Post #: 863

RE: BME 115 Any Fi... - 10/4/2007 11:57:09 PM   
RTK


 

Posts: 4089
Joined: 4/20/2003
From: CENTRAL , CA, USA
Status: offline 		dbcaster--You are correct, with the "stock" WB carb you will either be too lean on the top and OK in the low/mid OR you will be rich/dieing in the low/mid and fine on the high.
If it sounded like I was saying this engine was perfect with the original WB forgive me. I can make it run acceptable in the low/mid, but with sacrificing high or visa versa.
Although, I now "believe" the 3 needle carb should fix any short comings, only time will tell. There might be others solutions as well. Altavillans, Patricks, and or others might all work out well.

< Message edited by RTK -- 10/5/2007 12:42:59 AM >

(in reply to dbcaster)