K&B .61 engine?
08-09-2006 | 07:47 PM
#76
RE: K&B .61 engine?
root, do an rpm reading with and without the fine mesh Bru-line filter. In my limited tests, the filter acts as a restrictor plate. I saw a drop in peak rpms with the filter installed. Your fuel mileage will go up because the engine will not rev out like before. As the filter only comes in one size (I think), this effect will be noticed on larger engines more than small ones. At least this is what I found. If I was going to use a Bru-line on an engine larger than .45, I'd think about using the coarse filter element.
08-09-2006 | 08:56 PM
#77
RE: K&B .61 engine?
The BruLine filters obviously cause a slight restriction but I've never tached an engine with and without to find the difference. I suspect it's quite small. The filters (coarse/fine) are sometimes used as a tuning aid with CL stunt engines because the fine filter has about the same affect as reducing the venturi size by .020" and the coarse by about .010" on .60 size engines. Basically this means you get better fuel draw without having any spray coming out of the carb to mess up the outside of the engine. It's a struggle getting them on a Rossi 45 carb though 
08-09-2006 | 10:48 PM
#78
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From: Mary Esther, Florida, FL
RE: K&B .61 engine?
Root:
Sorry, forgot to answer about the plug in the other thread. FBD has said it though, I use the K&B 1L plug in the 6550 and 6560 engines.
Bill.
PS: Once you've used the Bru-Line filter you wont want to do without it. wr.
Sorry, forgot to answer about the plug in the other thread. FBD has said it though, I use the K&B 1L plug in the 6550 and 6560 engines.
Bill.
PS: Once you've used the Bru-Line filter you wont want to do without it. wr.
08-10-2006 | 12:28 AM
#79
Senior Member
RE: K&B .61 engine?
ORIGINAL: Flyboy Dave
You do not need, nor will it help to use an idle-bar plug in that engine.
Use a K&B-1L plug in it.
You do not need, nor will it help to use an idle-bar plug in that engine.
Use a K&B-1L plug in it.
Are you sure about that?
This K&B is the older, loop-scavenged variety, for the likes of which the idle-bar glow-plug was invented.
It is more likely to throw raw fuel at the glow element, against which the idle-bar is supposed to protect.
There are some Schneurle engines (MDS?) that also need the idle-bar to run right.
08-10-2006 | 01:29 AM
#80
My Feedback: (21)
RE: K&B .61 engine?
Yep....I'm sure about that. In fact, when I started out in r/c, I just assumed
that idle bar plugs were for engine's that idled, and plain glow plugs were for
engines that ran wide open, like c/l engines. Then one day a friend (he and his
son were into c/l carrier competition) asked me why I was still using idle bar
plugs?
Well, long story short, he proved to me that the engines (K&B .61's) would
not only run better, but idle better without the idle bar. The reasoning, which
proved to be true, was....why would you want to block the fuel from the fire.
If you want something to ignite, why would you block, or hamper that from
happening ?
The carb mixes the fuel with the air. If you have such a junky carb, that when
the mixture in the combustion chamber is still in a "raw fuel" state....you need
a better carb....not something blocking that mess from getting to the fire.
I think Duke Fox invented the idle bar plug, in a vain attempt to keep plugs from
drowning out from the "splash of fuel" coming from those pieces of junk he
called carburetors. [X(]
Bottom line....the baffle on the piston doesn't cause droplets of fuel to get on
the plug....rather it is for scavenging the cylinder....oweing to the lack of
scavenging found in the later Schneurle type engines.
FBD.
that idle bar plugs were for engine's that idled, and plain glow plugs were for
engines that ran wide open, like c/l engines. Then one day a friend (he and his
son were into c/l carrier competition) asked me why I was still using idle bar
plugs?
Well, long story short, he proved to me that the engines (K&B .61's) would
not only run better, but idle better without the idle bar. The reasoning, which
proved to be true, was....why would you want to block the fuel from the fire.
If you want something to ignite, why would you block, or hamper that from
happening ?
It is more likely to throw raw fuel at the glow element, against which
the idle-bar is supposed to protect.
the idle-bar is supposed to protect.
the mixture in the combustion chamber is still in a "raw fuel" state....you need
a better carb....not something blocking that mess from getting to the fire.
I think Duke Fox invented the idle bar plug, in a vain attempt to keep plugs from
drowning out from the "splash of fuel" coming from those pieces of junk he
called carburetors. [X(]
Bottom line....the baffle on the piston doesn't cause droplets of fuel to get on
the plug....rather it is for scavenging the cylinder....oweing to the lack of
scavenging found in the later Schneurle type engines.
FBD.
08-10-2006 | 04:52 AM
#81
Senior Member
RE: K&B .61 engine?
Well, Dave, I guess this is not as I previously perceived it.
It's never too late to learn...
So those MDS engines that do have Schneurle porting, need the idle-bar on the plug because they have a junk carburettor, that produces huge drops that can dowse the glow element.
This seems believable enough...
With the piston baffle, the intake is indeed sent up by it, to scavenge the exhaust gasses down and out through the exhaust.
It is also prevented from just going straight over the piston and out the exhaust port...
But as a consequence, fuel is thrown in the direction of the glow-plug. If the droplets are large, the element can be dowsed.
Schneurle porting does away with the baffle, since the ports are angled up and away (in) from the exhaust port, scavenging the exhaust gasses without resorting to a baffle. TST (Travasi Super Tiger) is similar, but the ports are placed similarly to a loop-scavenged engine and are only angled up, to achieve what the baffle does.
It's never too late to learn...
So those MDS engines that do have Schneurle porting, need the idle-bar on the plug because they have a junk carburettor, that produces huge drops that can dowse the glow element.
This seems believable enough...
ORIGINAL: Flyboy Dave
Bottom line....the baffle on the piston doesn't cause droplets of fuel to get on
the plug....rather it is for scavenging the cylinder....owing to the lack of
scavenging found in the later Schneurle type engines.
Bottom line....the baffle on the piston doesn't cause droplets of fuel to get on
the plug....rather it is for scavenging the cylinder....owing to the lack of
scavenging found in the later Schneurle type engines.
It is also prevented from just going straight over the piston and out the exhaust port...
But as a consequence, fuel is thrown in the direction of the glow-plug. If the droplets are large, the element can be dowsed.
Schneurle porting does away with the baffle, since the ports are angled up and away (in) from the exhaust port, scavenging the exhaust gasses without resorting to a baffle. TST (Travasi Super Tiger) is similar, but the ports are placed similarly to a loop-scavenged engine and are only angled up, to achieve what the baffle does.
08-10-2006 | 08:16 AM
#82
RE: K&B .61 engine?
My experiance is that you can get a lower idle with the idle bar plug. I see no differance in performance if you compare the idle bar plug to the equavlent non idle bar plug, the Fox RC standard and idle bar are the same plug. The engine will perform the same on either plug. If you are getting better performance with the 1L over the K&B idle bar then there must be some differance in the heat range of the plug. I recall that the K&B idle bar plug is slightly cooler, but not sure. There is no need for a "straight shot" as the ignition occures with any molecule in direct or near contact with the element and the flame will propagate through the sides of the idle bar just fine.
I recall that the TST ported ST .60 Blue Head needed an idle bar plug worse than the baffled ST .60 Blue Head.
I recall that the TST ported ST .60 Blue Head needed an idle bar plug worse than the baffled ST .60 Blue Head.
08-10-2006 | 08:24 AM
#83
RE: K&B .61 engine?
My earlier rpm readings on the 6550 were with an idle bar plug. This morning I'll test the engine with an O.S. #8, both idle and peak, and report back. Also I'll check peak with and without a fine mesh Bru-line. My tests on the filter were with four strokes, so we'll see if this also applys to two strokes.
08-10-2006 | 10:36 AM
#84
My Feedback: (21)
RE: K&B .61 engine?
A few years ago, I pressed a "bench run" only like new OS .61 RF engine
into service in my old Super Kaos. It started, ran, and idle nicely....but on
landings the engine would die out. I adjusted the carb and played with it,
I knew it was set perfectly. Finally, after a few dozen of these dead on the
runway episodes I pulled the plug....yep, a darned idle bar plug was the culprit.
Blocking the fuel from the fire would cause the engine to die out after about
20 seconds with the plane coming in for a landing....time after time, after time.
I felt kinda' foolish when I discovered the idle bar plug, because I had overlooked
it when I installed the engine.
I got a wonderful toss out of that idle bar plug....I got about 50 yards with it
with a beautiful end over end spinning rotation.
Like I said in my previous post, I had it "proven" to me that my K&B would not
only run better, but would idle better with a plain ol' K&B 1L plug, and it was so.
I wish I had a nickle for every engine that was destroyed by an idle bar plug,
when the bar fell off. Most everyone that has been around awhile has either
had this happen, or knows someone who had this happen to them.
I don't know a thing about MDS engines, and what they run on.
The baffled piston/idle bar story is an Old Wives tale....it ain't so.
FBD.
into service in my old Super Kaos. It started, ran, and idle nicely....but on
landings the engine would die out. I adjusted the carb and played with it,
I knew it was set perfectly. Finally, after a few dozen of these dead on the
runway episodes I pulled the plug....yep, a darned idle bar plug was the culprit.
Blocking the fuel from the fire would cause the engine to die out after about
20 seconds with the plane coming in for a landing....time after time, after time.
I felt kinda' foolish when I discovered the idle bar plug, because I had overlooked
it when I installed the engine.
I got a wonderful toss out of that idle bar plug....I got about 50 yards with it
with a beautiful end over end spinning rotation.
Like I said in my previous post, I had it "proven" to me that my K&B would not
only run better, but would idle better with a plain ol' K&B 1L plug, and it was so.
I wish I had a nickle for every engine that was destroyed by an idle bar plug,
when the bar fell off. Most everyone that has been around awhile has either
had this happen, or knows someone who had this happen to them.
I don't know a thing about MDS engines, and what they run on.
The baffled piston/idle bar story is an Old Wives tale....it ain't so.
FBD.
08-10-2006 | 11:39 AM
#85
Senior Member
My Feedback: (14)
RE: K&B .61 engine?
ORIGINAL: Flyboy Dave
A few years ago, I pressed a "bench run" only like new OS .61 RF engine
into service in my old Super Kaos. It started, ran, and idle nicely....but on
landings the engine would die out. I adjusted the carb and played with it,
I knew it was set perfectly. Finally, after a few dozen of these dead on the
runway episodes I pulled the plug....yep, a darned idle bar plug was the culprit.
Blocking the fuel from the fire would cause the engine to die out after about
20 seconds with the plane coming in for a landing....time after time, after time.
I felt kinda' foolish when I discovered the idle bar plug, because I had overlooked
it when I installed the engine.
I got a wonderful toss out of that idle bar plug....I got about 50 yards with it
with a beautiful end over end spinning rotation.
Like I said in my previous post, I had it "proven" to me that my K&B would not
only run better, but would idle better with a plain ol' K&B 1L plug, and it was so.
I wish I had a nickle for every engine that was destroyed by an idle bar plug,
when the bar fell off. Most everyone that has been around awhile has either
had this happen, or knows someone who had this happen to them.
I don't know a thing about MDS engines, and what they run on.
The baffled piston/idle bar story is an Old Wives tale....it ain't so.
FBD.
A few years ago, I pressed a "bench run" only like new OS .61 RF engine
into service in my old Super Kaos. It started, ran, and idle nicely....but on
landings the engine would die out. I adjusted the carb and played with it,
I knew it was set perfectly. Finally, after a few dozen of these dead on the
runway episodes I pulled the plug....yep, a darned idle bar plug was the culprit.
Blocking the fuel from the fire would cause the engine to die out after about
20 seconds with the plane coming in for a landing....time after time, after time.
I felt kinda' foolish when I discovered the idle bar plug, because I had overlooked
it when I installed the engine.
I got a wonderful toss out of that idle bar plug....I got about 50 yards with it
with a beautiful end over end spinning rotation.
Like I said in my previous post, I had it "proven" to me that my K&B would not
only run better, but would idle better with a plain ol' K&B 1L plug, and it was so.
I wish I had a nickle for every engine that was destroyed by an idle bar plug,
when the bar fell off. Most everyone that has been around awhile has either
had this happen, or knows someone who had this happen to them.
I don't know a thing about MDS engines, and what they run on.
The baffled piston/idle bar story is an Old Wives tale....it ain't so.
FBD.
---------------
You know, Dave, idle bar plugs go bad too, without necessarily burning out.
All kidding aside, I do not think the RF would appreciate an idle bar plug. I do have a hard time seeing how it would cause the engine to quit on approach, unless that particular plug had a damaged element.
I keep as many types of plugs in my field box as possible. You never know when some oddball plug will be just right on a given day.
08-10-2006 | 11:47 AM
#86
RE: K&B .61 engine?
OK sports fans, here's the exciting results of the idle bar/ Bru-line tests:[ul]
[*With Bru-line filter........................11,970 peak]
[*Without filter................................12,360 peak]
[*with #8 O.S. ...............................12,360 peak...................Idle 2,100]
[*with Idle Bar................................12,360 peak...................Idle 2,100]
[/ul]
If I flew in dusty conditions, I sure wouldn't worry about 400 peak rpm. If I was racing, the filter would stay in the junk box.
Edited to add: It was much cooler and less humid this morning than during my previous run with the 11x7APC. I picked up 600 rpm from the earlier test.
[*With Bru-line filter........................11,970 peak]
[*Without filter................................12,360 peak]
[*with #8 O.S. ...............................12,360 peak...................Idle 2,100]
[*with Idle Bar................................12,360 peak...................Idle 2,100]
[/ul]
If I flew in dusty conditions, I sure wouldn't worry about 400 peak rpm. If I was racing, the filter would stay in the junk box.
Edited to add: It was much cooler and less humid this morning than during my previous run with the 11x7APC. I picked up 600 rpm from the earlier test.
08-10-2006 | 12:20 PM
#88
RE: K&B .61 engine?
That was a fine mesh filter FBD. I don't have a coarse filter to test. I was starting to hurl obscenities around the neighborhood trying to get the filter over the belled intake of the K&B. Finally I took the filter element out, stretched the filter body over the intake, then re-installed the element.
08-10-2006 | 12:26 PM
#89
My Feedback: (21)
RE: K&B .61 engine?
Artisan....
....that isn't the only instance....I've tuned many an engine at the field for others
that ran like poop, and found the idle bar plug to be hindering, not helping the
situation over the past three decades. Maybe others have had different experiences.
I have never seen an idle bar plug make an engine run better or idle better
than a regular plug. Blocking the fire from the fuel has not proven be an effective
way to enhance an engines performance....in my experience.
Now, if someone has a junky carb that is hurling droplets of fuel at the glow plug,
an idle bar plug may help. Thankfully, I don't have any junky carbs.
Sometimes, when I run low on glow plugs....I wish I had all those plugs back that
I gave away at the field in order to get someones engine running properly.
FBD.
....that isn't the only instance....I've tuned many an engine at the field for others
that ran like poop, and found the idle bar plug to be hindering, not helping the
situation over the past three decades. Maybe others have had different experiences.
I have never seen an idle bar plug make an engine run better or idle better
than a regular plug. Blocking the fire from the fuel has not proven be an effective
way to enhance an engines performance....in my experience.
Now, if someone has a junky carb that is hurling droplets of fuel at the glow plug,
an idle bar plug may help. Thankfully, I don't have any junky carbs.
Sometimes, when I run low on glow plugs....I wish I had all those plugs back that
I gave away at the field in order to get someones engine running properly.
FBD.
08-10-2006 | 12:45 PM
#90
RE: K&B .61 engine?
I should have said that the idle bar plug will improve idle ON ENGINES THAT NEED IT. I don't recall that the K&B particularly needed them, some baffled engines do not. I do know that the ST Blue Head, both baffled and TST, need them. As well as the original Fox Eagle. The idle bar does not restrict fuel from getting to the element. In fact during compression when the fuel ignites it is traveling mostly sideways, as opposed to the intake phase when it is going up at an angle.
08-11-2006 | 03:08 AM
#91
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From: GeelongVictoria, AUSTRALIA
RE: K&B .61 engine?
I have one of these engines NIB (#6550) from when I 1st started in this hobby. It sits in the engine drawer in my shed, unused and generally ignored. I did put some after run oil into it when I got it and on occasion, fit a prop to it to turn it over and spread the oil around inside.
This thread has got my interest in perhaps fitting it into a .46 sized sport model.
Summing up on the prop tests etc, An 11.5 x 7 or 12 x 6 Prop for general sports flying? (Not 3D)
Can anyone tell me how loud they are with the stock muffler? Noise is becoming an issue at the field I fly at and some of the older motors do not measure up. For example another guy flying a K & B .65 Sportster, removed the baffle from the stock exhaust and the motor failed a noise test. (Max 98 Db)
As a reference, engines such as my Super Tigre G.51, with the stock exhaust, come in around 93Db (as measured with the clubs equipment)
This thread has got my interest in perhaps fitting it into a .46 sized sport model.
Summing up on the prop tests etc, An 11.5 x 7 or 12 x 6 Prop for general sports flying? (Not 3D)
Can anyone tell me how loud they are with the stock muffler? Noise is becoming an issue at the field I fly at and some of the older motors do not measure up. For example another guy flying a K & B .65 Sportster, removed the baffle from the stock exhaust and the motor failed a noise test. (Max 98 Db)
As a reference, engines such as my Super Tigre G.51, with the stock exhaust, come in around 93Db (as measured with the clubs equipment)
08-11-2006 | 08:04 AM
#92
RE: K&B .61 engine?
I think it may pass the 98 Db test, but just barely. It is loud. Those prop sizes from 12-6 to 11-7 are sport and pattern sizes. With a light classic pattern plane it won't hover but it will have enough vertical to do the large loops and uplines required for pattern.
08-11-2006 | 03:27 PM
#93
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RE: K&B .61 engine?
I'm running a 11x7 APC today (had a zinger 11x7.5 yesterday but not enuf fly wheel to keep a low idle) and just took off my long homemade rubber muffler extensions.
I noticed an undeniable db increase along with a noticable speed increase-
I'm still running on the rich side cause of 15% all synthetic fuel and I'm using a coarse carb filter over the venturi and she's up to 11,650 rpm.
My low end is still fluctuating from 2200 up till 3000. Why?, I don't know.
Hope this info helps all.
root
I noticed an undeniable db increase along with a noticable speed increase-
I'm still running on the rich side cause of 15% all synthetic fuel and I'm using a coarse carb filter over the venturi and she's up to 11,650 rpm.
My low end is still fluctuating from 2200 up till 3000. Why?, I don't know.
Hope this info helps all.
root
08-11-2006 | 06:42 PM
#94
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From: GeelongVictoria, AUSTRALIA
RE: K&B .61 engine?
Thanks Sport Pilot and Root.
A 12 x 6 might be the way to go.
I do also have some old Thunder Tiger 11x7.7 props (similar to Graupner props) that may be worth a try when I finally get around to firing this engine up.
I wonder if the Slimline Pitts Muffler (# 3112) would bring the Db levels down?
A 12 x 6 might be the way to go.
I do also have some old Thunder Tiger 11x7.7 props (similar to Graupner props) that may be worth a try when I finally get around to firing this engine up.
I wonder if the Slimline Pitts Muffler (# 3112) would bring the Db levels down?
08-14-2006 | 10:57 AM
#95
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From: irmo, SC
RE: K&B .61 engine?
I have the K&B .61 (6170 Twister) on order. It should arrive in a few days. I have several new OS A3 glow plugs also. Will this plug be OK for this engine?
08-14-2006 | 01:10 PM
#96
Senior Member
RE: K&B .61 engine?
James,
I would not recommend this glow-plug for any engine larger than a .30.
[link=http://www.os-engines.co.jp/english/line_up/plug/plug.htm]OS themselves say it is unfit for such engines[/link], except for break-in, where the rich mixture would counteract the engine's tendency to detonate on such a hot plug.
You would need a medium-cold plug for your engine. The OS #8 is the hottest OS plug that should be considered appropriate.
I would not recommend this glow-plug for any engine larger than a .30.
[link=http://www.os-engines.co.jp/english/line_up/plug/plug.htm]OS themselves say it is unfit for such engines[/link], except for break-in, where the rich mixture would counteract the engine's tendency to detonate on such a hot plug.
You would need a medium-cold plug for your engine. The OS #8 is the hottest OS plug that should be considered appropriate.
08-15-2006 | 01:44 AM
#98
My Feedback: (29)
RE: K&B .61 engine?
The K&B idle bar plug is more forgiving if your low needle is slightly rich or you idle for long time. My 6550 could idle for 15 minutes and when I snapped the throttle open it would sputter some and clean out, that is with the idle bar plug. A standard K&B plug could not idle for even a minute before it would die upon acceleration with the same carb setting.
08-21-2006 | 07:54 AM
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From: irmo, SC
RE: K&B .61 engine?
I purchased the K&B .61 Twister (6170) and put it on my scratch built Edge with a total weight of 5 pounds (same weight as it was with my Mecoa .46). I flew it for the first time with this engine and it had tremendous power. It will climb straight up at a little less than half throttle with an APC 13x4 sport prop, however making it hang on the prop was difficult. It would either fall out of the hover or climb out with very little throttle difference between the two (I hope that makes sense). I’m running the engine a little on the rich side as per the instructions and am getting right at 12,000 rpm with this prop. I could use some prop suggestions to give me better throttle control for 3d and hovering. Please help!!! Thanks.
