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Engine PORN: Brodak.049 MkII

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Engine PORN: Brodak.049 MkII

Old 01-16-2008, 01:04 PM
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DeviousDave
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Default Engine PORN: Brodak.049 MkII

Top 'o the day to ya Lads:

This engine was given to me this weekend by a friend (you know you have good friends when they make sure to buy an extra engine for you when they get one for themselves....[8D]) after wanting one of these since Toledo of last year. Should have bought one then, but.... At any rate:

Unlike the other Brodak 1/2A's, this one is made in Russia. It has a very stout build to it, reminds me of a cross between a Norvel Big Mig .049, a Zeus .049 diesel, and a Fora .02. There are design and styling elements from all three in this engine. As you can see from the pics, this engine is not set up to be a screamer, almost looks like they went out of their way to keep it from being a high-rpm motor from the start-which may not be out of line considering that it is being made for a CL company. As you can see in the pics, the engine is dimensionally very similar to a Norvel, just built beefier. Things I noticed:

Cheers:

Takes RC Short plugs!
Should draw fuel well
Plastic backplate
Deep knurling on the prop driver
Needle Valve has a setting mark dimple
Con Rod has an oil hole in the lower end!
Chromed sleeve
Long venturi

Jeers:

Takes RC Short Plugs!
Spraybar is Huge-Holy obstructed passageway, Batman!
Needle valve is held with a spring, no spring ratchet
Porting looks homely
Intake runners are huge and will not lend themselves well to hotrodding the motor
It's heavier than it could be..
Prop shaft is long and skinny.
Spray bar is pressed into the case

Side note: The case castng has a nub under the exhaust that makes it look like they are planning to add a muffler at some point. RC conversion would be very difficult on this engine given that the spray bar is pressed in and the ventri is angled too close to the cylinder. Instructions mention nitro setup, so it shouldn't be a very weak motor.... .. .

From the looks of the thing, it should be a workhorse motor that would fill the role of the CL BigMig .049. Can't wait to find out.








Old 01-16-2008, 02:51 PM
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Default RE: Engine PORN: Brodak.049 MkII

I've had one for a coupla months now, I concur on the whole short-plug thing (just WHEN will these people figure out that a turbo plugs are better anyway?). I don't know much about C/L, but it looks like it'll be a decent engine for 'em. Too bad it won't be worth much for R/C without the manufacturer essentially retooling the thing.
Old 01-16-2008, 03:48 PM
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Default RE: Engine PORN: Brodak.049 MkII


ORIGINAL: digital_trucker

I've had one for a coupla months now, I concur on the whole short-plug thing (just WHEN will these people figure out that a turbo plugs are better anyway?).
Many of the comments over in the Stuka Stunt forum have panned the standard plug usage. A couple of other reviews have pointed out that the head design will not allow easy modification for a turboplug. This engine has been discussed quite a bit there -- do a search for Brodak MKII or similar.
Old 01-16-2008, 04:13 PM
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Default RE: Engine PORN: Brodak.049 MkII

Thanks for the detailed images!
Might save me some money...

The intake looks very restricted, possibly a way to have a good fuel draw without muffler pressure?

There is one thing regarding the head design that I find odd. It is not only the standard plug and its threads that give additional volume but also the "side rim" since the gasket is recessed. Why don't they put the head gasket on a flat surface? Is there any problem to have the piston going all the way up in the sleeve?
I've seen this on e.g. the TT 07 as well and it seems like a rather bad idea to me. If one compares with the heads that do work, like cox and Norvel, these all have minimized the "stray" volumes for the combustion...
Old 01-16-2008, 05:10 PM
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Default RE: Engine PORN: Brodak.049 MkII

Nice thumb Dave![sm=thumbup.gif]

Have you run 'er up yet?
Old 01-16-2008, 10:59 PM
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Default RE: Engine PORN: Brodak.049 MkII

Dude, you've either got small hands or that spraybar is huge. I don't have a TD cracked open at the moment, but I don't recall the crankshaft inlet being a drilled round hole. Maybe you could put a degree wheel on it and find some easy horsepower there?
Old 01-16-2008, 11:30 PM
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Default RE: Engine PORN: Brodak.049 MkII

It may just be the pic, but it looks like the case could use a bit of lapping on the thrust bearing surface. Let us know how well it runs for you.

George
Old 01-17-2008, 03:01 AM
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Larry Driskill
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Default RE: Engine PORN: Brodak.049 MkII

Interesting.

And note what appears to be an "oiler groove" in the top of the crank journal from the venturi forward to the front of the case.

Duke Fox advocated an oiler, but he said stop it before you got all the way to the front.
Old 01-17-2008, 11:32 AM
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Default RE: Engine PORN: Brodak.049 MkII


ORIGINAL: RocketRob

Nice thumb Dave![sm=thumbup.gif]

Have you run 'er up yet?

Two things: It's wayyy to cold to be out in the prop blast with fuel on the fingers, and I cut my flipping finger while getting on the Chicago toll road (I90) when leaving GKamysz's wedding! Something dropped out of my backpack when I opened a pocket to get change for the camera-spying Revenue Enhancement Machine I heard something drop... While I merged onto the freeway I started groping in the dark and laid my hand on it without realizing it was my uh.. "pocket knife" that had fallen. I grasped it and felt it fold just as I realized my finger was in the serrated pinch point. SCHnick! Agh! M@#$%F@#$^&*! Probably looked drunk as I merged onto the freeway trying to pull a bandaid out of the first aid kit, ruined my tuxedo sleeve-I couldn't really stop anywhere until I had gotten way out of Gary, IN.

Anyone know what this engine likes for a prop and fuel? Performance #'s? I'm guessing it takes something like a 6-3 paint stirrer for a prop and spins 18-18.5k on 35%.... How close am I?
Old 01-17-2008, 11:36 AM
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Default RE: Engine PORN: Brodak.049 MkII


ORIGINAL: Larry Driskill

Interesting.

And note what appears to be an "oiler groove" in the top of the crank journal from the venturi forward to the front of the case.

Duke Fox advocated an oiler, but he said stop it before you got all the way to the front.
I had a 4-cycle once that had a groove spiral milled into the crank. It stopped short of the front of the case like you describe and swept the oil rearward when running. I think the crank was cast with the groove in it and then centerless ground. Wonder how well this style works? I mean, there's a groove for oil (or maybe just reduced crank drag?) but once it fills up, what keeps it from seeping out the front?
Old 01-17-2008, 11:41 AM
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Default RE: Engine PORN: Brodak.049 MkII


ORIGINAL: ptulmer

Dude, you've either got small hands or that spraybar is huge. I don't have a TD cracked open at the moment, but I don't recall the crankshaft inlet being a drilled round hole. Maybe you could put a degree wheel on it and find some easy horsepower there?

Looking at the engine, it looks like a lot of the secondary operations are done manually on fixtures. The ports for example are rough drilled.. I'm sure this saves a lot of money for them as CNC machines have got to be in short supply in a shop that makes larger, more profitable engines.

Looking at it, this motor would probably make a really good sport diesel. Might have to talk to Greg about that..[>:]
Old 01-17-2008, 11:48 AM
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Default RE: Engine PORN: Brodak.049 MkII


ORIGINAL: Mr Cox

Thanks for the detailed images!
Might save me some money...

The intake looks very restricted, possibly a way to have a good fuel draw without muffler pressure?

There is one thing regarding the head design that I find odd. It is not only the standard plug and its threads that give additional volume but also the "side rim" since the gasket is recessed. Why don't they put the head gasket on a flat surface? Is there any problem to have the piston going all the way up in the sleeve?
I've seen this on e.g. the TT 07 as well and it seems like a rather bad idea to me. If one compares with the heads that do work, like cox and Norvel, these all have minimized the "stray" volumes for the combustion...

Actually, this is a better way to design a head/cylinder interface-VA .049 MK II's and Cyclons are done this way. The top of the cylinder and head are nice and flat for a gasket surface, which allows you to sink the combustion chamber into the (taller) cylinder for better sealing. Come to think about it, most engines with bolt on heads (like O.S.) do this as well. One negative to the standard (Cox) way is that any buildup of head gaskets make for more room for a sealing problem and an untidy combustion chamber.

Speaking about combustion chambers, when I was with Greg this weekend I brought up the possibilty of partially filling an RC Short plug with a substance (not sure what yet) that would reduce the plug hole volume and make it act more like a turbo plug. This might be a good test mule engine for that.
Old 01-17-2008, 01:11 PM
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Default RE: Engine PORN: Brodak.049 MkII

ORIGINAL: Larry Driskill

Interesting.

And note what appears to be an "oiler groove" in the top of the crank journal from the venturi forward to the front of the case.

Duke Fox advocated an oiler, but he said stop it before you got all the way to the front.

I am not sure I am seeing the same thing. If you are referring the second last picture and the light coloured line on the left side of the crank, I think that is just a reflection of the light and not really a groove.

All in all, looks interesting and has room for improvement. A new head to take a turbo plug would be an easy project. Could even modify the current head to use as a clamp for a head button. Those transfers sure do look huge.

cheers, Graham


edit: I see it now, in the crankcase bearing area (4th picture down?) along the top side of the bearing.
Old 01-17-2008, 01:38 PM
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Default RE: Engine PORN: Brodak.049 MkII

The problem with regular ol' short plugs isn't the hole for the element, it's the fact that the teeny-weensy space between the threads of the plug and the head become part of the combustion chamber. Not a real issue on the bigger engines, but it get's important quick on 1/2A and smaller.
Old 01-17-2008, 01:47 PM
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Default RE: Engine PORN: Brodak.049 MkII

ORIGINAL: DeviousDave
Actually, this is a better way to design a head/cylinder interface-VA .049 MK II's and Cyclons are done this way. The top of the cylinder and head are nice and flat for a gasket surface, which allows you to sink the combustion chamber into the (taller) cylinder for better sealing. Come to think about it, most engines with bolt on heads (like O.S.) do this as well. One negative to the standard (Cox) way is that any buildup of head gaskets make for more room for a sealing problem and an untidy combustion chamber.

Speaking about combustion chambers, when I was with Greg this weekend I brought up the possibilty of partially filling an RC Short plug with a substance (not sure what yet) that would reduce the plug hole volume and make it act more like a turbo plug. This might be a good test mule engine for that.
Hmm, now I'm confused again...

I thought the problem with a regular plug was the volume contained in threads which are included in the combustion but don't have access to fresh fuel. To me the design of the MkII then produces a similar volume at the rim of the head below the seal. Surely this volume cannot have fresh fuel in it and it will then just "dampen" the combustion?

There are regular plugs with a smaller hole in the center (e.g. from Merlin) but this to me is very similar to what can be adjusted by simply removing/reducing shims?

I've tried a Merlin plug and it didn't seem to change much on the CS/Brodak appart from being colder...
Old 01-17-2008, 02:16 PM
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Default RE: Engine PORN: Brodak.049 MkII


ORIGINAL: digital_trucker

The problem with regular ol' short plugs isn't the hole for the element, it's the fact that the teeny-weensy space between the threads of the plug and the head become part of the combustion chamber. Not a real issue on the bigger engines, but it get's important quick on 1/2A and smaller.

Hmm.. I would have thought that a major change in combustion chamber volume would be more suspect than thread leakage-the threads are filled with oil, which is incompressible, and I've never seen oil seeping out past the glow plug gasket...
Old 01-17-2008, 02:21 PM
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Default RE: Engine PORN: Brodak.049 MkII


ORIGINAL: Mr Cox
There are regular plugs with a smaller hole in the center (e.g. from Merlin) but this to me is very similar to what can be adjusted by simply removing/reducing shims?
I don't have any empirical data to prove it, but I think the 'problem' with the RC short plug vs. turbo plug is that the turbo plug's is additional combustion chamber volume that is unused. When you take out a shim to increase compression all you are doing is shortening the combustion chamber relative to the piston at TDC. Maybe someone else can contribute here, it's an interesting subject..
Old 01-17-2008, 03:51 PM
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Default RE: Engine PORN: Brodak.049 MkII


ORIGINAL: DeviousDave
...I mean, there's a groove for oil (or maybe just reduced crank drag?) but once it fills up, what keeps it from seeping out the front?
Nothing. I think that's the point Larry was making. It will probably run with a "wet nose".

This groove has been done for BB engines that are run in an environment where the bearings are subject to a lot of junk getting in there. Might also help if you happen to be using it as a pusher.

I think the spiral groove that runs the oil to the back is called a labrynth seal.

George
Old 01-17-2008, 05:07 PM
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Default RE: Engine PORN: Brodak.049 MkII

Actually, this is a better way to design a head/cylinder interface-VA .049 MK II's and Cyclons are done this way. The top of the cylinder and head are nice and flat for a gasket surface, which allows you to sink the combustion chamber into the (taller) cylinder for better sealing
Hmmm. I think either way is the same. With a cox/norvel type seal, you can lap the bottom of the head for a nice gasket surface, while the surface in the cylinder will always be a machined surface which isn't as good as lapped. With the brodak setup, you can lap the top of the cylinder, but due to the spigot sticking out of the centre of the head, the sealing surcace on the head will still only ever be a machined surface. It's still the same seal set up, just the other way around as far as surface finishes go.

Old 01-17-2008, 09:39 PM
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Default RE: Engine PORN: Brodak.049 MkII


ORIGINAL: gcb



I think the spiral groove that runs the oil to the back is called a labrynth seal.

George
If that is not what it is called, it SHOULD be. While I had been unfamilialar with the term it is very descriptive, not to mention catchy. Now I need to come up with some reason to work it into a conversation

jess
Old 01-18-2008, 08:38 AM
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Default RE: Engine PORN: Brodak.049 MkII


ORIGINAL: GrahamC
Those transfers sure do look huge.

cheers, Graham

Yeah, I think that's going to be a limiting factor for people with a need for speed and a dremel tool. Having huge intake runners might seem like a good thing, but you are trading volume for velocity. Ever seen the intake runners on a VA Mk1? Tiny. Even a .7hp 37,000rpm Cyclon has less radical intake runners than that.
Old 01-18-2008, 10:14 AM
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Default RE: Engine PORN: Brodak.049 MkII


ORIGINAL: longdan
Hmmm. I think either way is the same. With a cox/norvel type seal, you can lap the bottom of the head for a nice gasket surface, while the surface in the cylinder will always be a machined surface which isn't as good as lapped. With the brodak setup, you can lap the top of the cylinder, but due to the spigot sticking out of the centre of the head, the sealing surcace on the head will still only ever be a machined surface. It's still the same seal set up, just the other way around as far as surface finishes go.
Perhaps. But remember that manufacturers have spent a lot of time designing glow heads and plugs. Case in point would be the difference between the standard and TD Cox heads. The TD has a squish band that not only supplies more compression but also shapes the burn. I think the Brodak engine was designed so the owner could grab a standard plug out of his (or her) flight box and not be concerned with proprietary heads. Fitting a turbo or Nelson plug would have been good but remember this is a sport engine not a nitro burning power house.

George
Old 01-18-2008, 10:25 AM
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Default RE: Engine PORN: Brodak.049 MkII

ORIGINAL: jessiej


ORIGINAL: gcb



I think the spiral groove that runs the oil to the back is called a labrynth seal.

George
If that is not what it is called, it SHOULD be. While I had been unfamilialar with the term it is very descriptive, not to mention catchy. Now I need to come up with some reason to work it into a conversation

jess
I think you will need '60's shape and style glasses plus a plastic pocket protector to use that phrase in mixed company
Old 01-18-2008, 12:41 PM
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Default RE: Engine PORN: Brodak.049 MkII


ORIGINAL: DeviousDave
Yeah, I think that's going to be a limiting factor for people with a need for speed and a dremel tool. Having huge intake runners might seem like a good thing, but you are trading volume for velocity. Ever seen the intake runners on a VA Mk1? Tiny. Even a .7hp 37,000rpm Cyclon has less radical intake runners than that.

After looking agan at the pictures, I wonder if this was an attempt to remove as much dead weight as they could. The engine lists as 1.7ounces (48g the TeeDee 049 being 46g). These large transfers will probably be somewhat detrimental to the high end potential of this engine. Still, probably make a nice mannered sport engine. I wonder how the size of the transfers would affect idling. The stock Fox stunt .35 often has what they refere to as "burp" on some inside (or is outside) maneauvers which they cure by blocking off part of the transfer/bypass (often with a wedge of wood).

The more and more I look at the this I feel tempted to call Brodak and get one just to play with. I am not sure but I think it may even have the same mounting as the TeeDee (if someone knows for sure please correct me if I am incorrect)

cheers, Graham
Old 01-18-2008, 04:52 PM
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Default RE: Engine PORN: Brodak.049 MkII


ORIGINAL: skaliwag

ORIGINAL: jessiej


ORIGINAL: gcb



I think the spiral groove that runs the oil to the back is called a labrynth seal.

George
If that is not what it is called, it SHOULD be. While I had been unfamilialar with the term it is very descriptive, not to mention catchy. Now I need to come up with some reason to work it into a conversation

jess
I think you will need '60's shape and style glasses plus a plastic pocket protector to use that phrase in mixed company

Not at all. One needs only articulate company.

jess

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