bullittman281

Hello,
Bullittman here. I need some help dealing with a brodak .049 MKI engine and the Baby Clown plane. The biggest problem is the engine. I don't have years of experiance with glow engines but I know what it takes to make them go or so I thought. This is my first actual model. I've got a couple other engines i've ended up with but have never tried to fly them, just fired them up on the bench. The brodak though is giving me fits. I've followed the instructions to the tee and it still aint happening. After much fussing around bench testing it I finally got it running but not well. On the bench I was using a 2oz fuel tank. I live in Colorado Springs and 1/2A sised anything is nonexistant but there is lots of rc car stuff. The only fuel I could find that wasn't a gallon jug is car fuel. 16% nitro, 15% oil. I added some Sig castor oil to bring oil content up to around 22%, the amount specified by brodak. After a great deal of fighting it i finally was able to get it to run continuously on a ragged 4S/2S needle setting. If I try to lean it out any more to get it to just two stroke it acts like it get hot and looses compression. I'm talking ONE or TWO click in on the needle. It will clean up and start screaming like I think it should but then it slowly starts slowing down and then ultimately dies. The engine is imposible to start when hot. The head has to be cool if it is going to start. Performance doesn't seem very spectacular either. I have a free flight Cox heli engine for comparison. I believe it is a shure start. Running on the same 6x3 prop I was geting at best 11Krpm out of the Brodak before it starts slowing down. The cox turns the same propeller on the same fuel at 13K+RPM. My understanding is the shure starts are also gutless. Performace on the Brodak seems even lower. Correct me if I'm wrong. I've experemented with differnt props but it runs about the same though obviously faster on a smaller pitch or diameter prop. I can't get it to run in a clean two cycle with out it slowing down and dieing. All of this is without the muffler. puting the mufler on it only makes it worse. I have some Supercat 1/2A 35% nitro fuel that I tried and it ran faster but still wont run clean and stay running. At this point I have about a pint of fuel ran through it. I keep hoping it jsut needs more break in time but i'm not shure.

In an effort to find a cause for the difficulties I removed the spray bar to look for burrs or something cloging the needle up but I faild to note which way the hole in the spray bar was pointed. I reassembled it with the hole facing strait down and I have tried differnt orientations but I am not shure exactly what the correct orientation is. If some body could clue me in on what correct is it would be much appreciated. Also in my effort to fing a cause for my difficulties I removed the crank case cover looking for something and I noticed that the engine has so much end play that the con-rod is rubbing on the rear crank case plug when I flip it through and is wearing the back of the rod flat. This doesn't really seem propper to me but when the engine runs the prop is pulled foward away from the rear plug. Also since new the engine has had a rod knock of sorts from what sound like either the wrist pin or the big end of the rod. The clicking noise is only audable when the engine has just been primed and is very easy to turn. I has good compression though. I don't know if any of this is normal or if I have a poor motor? My experience is limmited to a Cox .049 and a TD .010. Even the TD is easier to hand start than the Brodak. Any advice would be greatly appreciated.

After I finnished the Baby Clown I mounted the Brodak .049 on it and have a 1/4oz stunt wedge tank. The engine is a bit easier to start on the model but it is still unhappy about starting or running. I cannot get the engine to run the tank dry. Pediod. Maby half. It runs and dies with out ever being an air buble in the line to cause it to die. No amount of needle adjust ment will get it to survive the whole 1/4 oz. this includes turning the plane on its side to simulate centrifugal(sp) force of the model flying. I get maybe 1 miniute run time out of it, maby. The weather here has been foul so I haven't had a chance to try to go and fly it but I'm not expecting much. At this point I am very dissapointed with my engine choice. I went this rout hoping to avoid the scalping on Flea Bay for Cox parts. Sorry for such a long post and please forgive my bad spelling. If any body has some advice for me it would be greatly appreciated. Thank you.


Bullittman

combatpigg

My Feedback: (3)

BM, I think what you got is typical. I am surprised that Brodak wants to have their good name associated with this sub-standard offering. Get a Norvel, [they're all over the place]....or at least an AP .061 and then you will have enough power to fly something besides some glider type thing.

lildiesel

Bullittman -- you also might want to post your Brodak "breaking in" woes over on the Control Line forum. I'm fairly sure that more people are flying Brodak 1/2A engines over there than on this forum, but some of the engine gurus here ought to chime in with some useful ideas eventually.

Good luck and have fun.

combatpigg

My Feedback: (3)

There's no magic break in formula that will give this engine the extra 5000 rpm needed to keep pace with an average AP .061. At 6000 feet no less. That heavy iron piston can only be made to go up and down so fast.

skaliwag

My Feedback: (1)

CP... The Mk1 was made by CS... The Mk11 is being made in Maldovia.

bullittman281 ... Are you at 6000Ft?.... this could make a difference. You may need the "Tiger" (Nitro).. Plus Your engine may still be in need of break in. If it doesn't kick in I think perhaps you should send it back. I have found the Brodak people to be very accomadating.

Yuu

You wrote that when you get the engine to run 'two cycle' and fast, you wrote it gets hot and slows down. DUH!! It's NOT fully broken in yet!! The cylinder is getting HOT and expanding to make the hole SMALLER.....and the piston is getting HOT, making the piston BIGGER... and they don't fit anymore!!! The engine needs more time on the bench, breaking in. Say, another 'pint' of fuel...in small amounts, say 1/4 ounce, with a 'cool down' period each time before you re-start. So cool you can put your lips against the glow plug and it's not warm. And DON"T run it fast!! The piston and cylinder need time to polish and harden each other 'breaking in.'

Then... you are using a 1/4 ounce "Stunt wedge tank". Guess what?! That tank is a 'wedge' .. triangular....so the centrifical force while flying control line will push the fuel to the outside of the circle, and the outside of the tank....so you have even fuel flow while flying upright or inverted. It will run the tank dry. BUT YOU ARE USING IT AS A STATIC TANK!! THERE IS NO CENTRIFICAL FORCE PUSHING THE FUEL TO THE OUTSIDE OF THE CIRCLE; SO IT OPERATES AS A REGULAR TANK, with the fuel pick-up at the CENTER of the tank ... DUH!! The fuel pick-up is above the surface of the fuel, so the engine "sucks air". No wonder it only uses half a tank before it dies. Turn the tank on the tast stand so the fuel pick-up tub is TO THE BOTTOM.... then it will drain the tank. Run another pint of fuel, one small tank at a time.....But don't run it HOT. Run in WILL take time, but your engine will be MUCH better for it.

Andrew

At first, I thought the same WRT to the tank, but rereading Bullittman's post carefully, he has done just that.

He's really looking for some help here -- and has indicated that he doesn't have a lot of experience with glow. We can all give useful advice without being critical of his inexperience.

The CS/Brodak engine doesn't have the best reputation. Around here, we might say he had a pig in a poke and all the tinkering in the world may not help improve the performance. Additional break-in time will probably help -- the steel/steel and steel/cast iron P/C combos took a long time to come in, but while not necessarily stump pullers, they would last forever.

I agree with skaliwag -- give it some more time. If it doesn't get any better, send it back for a workover, replacement, or tradein for a MK II.

bullittman281

hello,
Bullittman here. Yuu, THERE IS NO NEED TO SCREEM AT ME! I understand how as stunt wedge tank works.... DUH! Andrew was able to note that I turn the plane on its side so the pick up is at the bottom But doing this causes it to lean out and die. NO amount of needl adjustment will get it to stay running when I turn the plane. I'm gonna bench mount it and runn it a whole bunch more and see if htings improve. I'll post back later on my efforst. Thanks for the replies but NO SCREEMING please, thank you.

Bullittman

fizzwater2

My Feedback: (61)

What size prop are you running on the engine during this break in?

Andrew

Probably, since the tank is located on the outboard side of the plane, turning it dropped the tank well below the venturi, causing the lean condition. Get it back on the bench, use a 1 (max 2) oz. tank mounted with the centerline of the tank level with the NV, small ID tubing and keep the tank as close to the engine as possible. The steel/steel and steel/cast iron combos usually were broken in with multiple heat cycling (Yuu recommendation) and rich running with short bursts of 2 stroking.

Another source of binding can be at the crankshaft/crankcase bearing area. As soon as the engine quits after getting hot, check for any tightness with the piston around BDC.

bullittman281

Hello,
fizzwater2, the props I've been messing with are 5 1/2 X 4 6X3 and 6x4 thought primarily the 6x4. It seems to like the bigger props. Right now I'm in the process of getting more time on it and seeing what it does. I know the instruction recomend either of the 6" props for running it in.
Andrew, I'm curious about the whole needle valve level vs tank height issue. Would cintrifigual(sp) force and turning the airplane on its side seem identicale to the engine or not? I assumed it would but I don't know. Tommarrow there's not suposed to be much wind so I may go and try it to see what happens. I'll let yu guys know what happens if I get to try to fly it. Thanks for the replies.

Bullittman

bullittman281

Hello,
I've been running the engine all morning trying to ge ttime on it. Its easier to start with out the muffler so all of my running has been with out the muffler. After I put about 1 hours on it I tried my selection of props to see what it did. The fuel is wild cat 16% nitro car fule that I've added castor to bring the oil content up to the 22% called for. I was a little gererous with the additional oil so its probibly a little more than 22%. When testing the different sized props the engine would run much faster (1000+rpm) right when it started and as it warmed up the engine would slow down. Does this mean the engine needs furthur running in? The compression hot is also better and i dont understand that one either being there are no rings but thats what I'm seeing. On the 6X4 prop once it warmed up and stablized(sp) I gould get maby 10K out of it if I wen too lean it would run for a bit and start to slow down slowly so the trick was to go as lean as it would go with out starting to run down. I can nver get a totaly 2T run out of it, it always has a bit of a miss if you will. On the 6X3 prop I got same results but maby 10.5K rpm. I tried my 5 1/2 X 4 and got 11.5k or so out of it. It never settles down into a perfect run though. I also have some Wild Cat super 1/2A 35% nitro fuel that i tried for a short run on the 5 1/2 prop but I don't know if this fuel is too hot or not for the Brodak. It ran noticably faster though. 14K RPM untill it buit some heat than it settled down to 12.5k to 13K RPM. Better but these numbers still seem really low. I recall the write up on stuka skunk works?? forum that 6/3 and 15k RPM but I don't remember off hand. I know a shure start will pull 13K on a 6X3. I'm gonna keep running it and see if things improve any.

Bullittman

Big Al-RCU

Not true. If a cylinder is heated it will expand and the hole will get larger not smaller.

SGC

Some of your problems maybe the fuel, steel/iron combinations like all castor at around 24%+ espescially dureing break in , it does sound like its still not run in fully yet.
Re the fuel tank/needle valve possition , turning the model on its side will drop the tank heoght in relation to the spraybar causeing the motor to go lean, I would recomend more bench running and a change to all castor fuel. Run the motor till it gets up to temp at the stable needle setting(were it doesnt get hot and quit) then pinch the fuel line to let it lean out and heat upm then pinch the line shut to stop it, let it cool right off, restart and repeat resetting the needle for the best stable run, keep repeating till it holds a good setting.
Stewart

BobHH

My Feedback: (18)

Many years ago Dad was up in Denver for about a year. I went and visited him and shipped one of my 1/2A racing deltas out to fly with the local clubs while up. My first attempted launch resulted in the Tee Dee.051 powered screamer to slowly settle to the ground. I was use to hand launcher her straight up at sea level!! I increased the nitro and the size of the prop and did get her to fly but no where near her performance at sea level. I wonder if the 6000 ft mark is causing some of your troubles.

Bob Harris

combatpigg

My Feedback: (3)

BM281......with the engine cold, prime it and bring the piston up to TDC. Move the piston up & down slightly, feeling for that compressed air "springy" feel. If the cylinder stays pumped for at least a few seconds, there is hope. I like to do a stage by stage build up and inspection under magnification of all parts. Unless you've handled real good running 1/2A engines before and know what the fits should be like, it is hard to explain without writing a book. You are aiming for no friction and zero slop, in other words...perfection. The only area where there should be some friction is at the top of the liner above the exhaust port, this is the critical break in area.

Ask Darren RRRagman about his 1/2A experiences in Arvada Colorado, he lurks around here sometimes.

bullittman281

Hello,
I've messed around with the Brodak all day running it and letting it cool down and haven't got any real improvement. Best I could manage is 10.5K to 11k RPM on a 6X3 and its still almost imposible to start.
Combatpigg, The motor doesn't really have that much compression ever. I dont know if its fair to compare it to a Cox shure start or not but I have one of those that is run-in but stil low time. It ALWAYS has lots of compression, hot or cold. It behaves more in the manner that you describe. I work on all kinds of yard equipment and have done that for many years so I'm familiar with gas motors and how they should behave. I have a couple of larger glow engines as well and when turning them over there is almost no blow by. even if you turn the engine over slow all the compression remains after TDC to flip it around. The brodak just kinda sogs over. There is no "snap" to it. If its brought to TDC and then one feels for a good seal it just kinda turns over. With LOTS of prime it gets better but at that point its flooded. The cox engine has lots of compression and almost no bleed down reguarless of temprature. Compare to picking a chain saw up with the starter rope and the chainsaw not droping down. Turning the same propeller on the same fuel I get 13K RPM or more and it holds it steady. Peak RPM isn't too lean to cause any trouble on the Cox. It just runs and runs.
I mounted the Shure start on my Baby Clown so I could accuratly compart the two engines. Even with out the spring starter the cox fires right up. Once the needle is set for max power the engine runs the same reguardless of the position of the airplane. whether I point the nose strait up or strait down it runs THE SAME. The Cox makes enough power with a 6X4 prop it wants to pull the plane strait up, even with full fuel. The brodak was VERY sensitive to changes in the airplane and rolling it over on its side was enough to kill it either from fuel starvation or flooding it depending on which way it turned the airplane. I could NEVER get it to stay running with the nose pointed strait up. I guess my question then is does a "good" brodak have anywhere close to that kind of draw or is that a Cox readey thing?
Something else that i've noticed that just doesn't seem right is the amount of clearne the conevting rod has on the crank pin. Fliping it over it makes a clicking noise and with the back plate off I can see the slop If I take something soft to push on the bottom of the piston. I don't know but that doesn't seem right to me. If it looks like a lemon, and it smells like a lemon, and it tastes like a lemon, it's a lemmon. Monday I'm gonna contact Brodak and see what they say cause I'm thinking I got a bad one. I was hoping the brodak would be a good replacement for a Cox and maybe even a quiet replacement because the Cox engines are LOUD but so far the brodak just isn't. Thanks for your help and I'll see what I can find out monday.


Bullittman

BMatthews

The difficulty starting it is likely a clue. I strongly suspect that you need more nitro. Small engines thrive on the stuff and 16% is not high at all for them. It probably needs more like 25%. Adding oil to the fuel was a good idea but at the same time it also reduces that 16% down even further.

The other option if you can manage to do it easily is to raise the compression ratio a little. But how you do that would depend on if there's some extra head gaskets in the engine or not. Or if the head uses a thick gasket that can be replaced by a thinner one.

I've never seen a Brodak engine so this last bit is very general.

gabe200

My Feedback: (21)

i have a cs .061 i dint have the problem youre having with youre engine im using sig 1/2a fuel with added castor oil my runs great it took a while to brake in

Japanman

I think you have a dud there in the cylinder to piston fit. Send it back for a replacement. I`d try for a trade to a MKII brodak wich has a hardchrome bore and should be a whole lot more durable, if not a little more peppy.
You have not done anything that would have damaged the compression seal to the point you talk about.

Stefan

Yuu

Bullittman... my sincere appology ... I did not intend to treat you as a dumb *****. My problem seems to be my 'mimicing' my grandsons and their "caustic" use of the language. Again, I appologize.
I'm just trying to help, so I found your post # 17 where you wrote "not much compression"....Skaliwag in post # 5 wrote "nitro"....Bruce in post #18 wrote "more nitro" and "more compression".
Somewhere I thought I read you wrote something about 'not much compression. When I was a kid, my Dad had a K & B .19 Torpedo... he had 5% Fox fuel for his Fox .35 Nobler, but the Torpedo was impossible to start. One day we tried some of my "racing fuel"...well, that's what it said on the can. Hobby shop said it was 15% nitro. That Torpedo ran great on 15% nitro. And just this year I read somewhere that extra nitro also helps cool...?? And, I also read that with more nitro, you have to reduce the compression... you wrote you thought the compression was low, right? So I'll join Skaliwag and Bruce and suggest 'more nitro'.
Another thing I saw was a request for info on the position of the needle and the spray hole. I think the spray hole must be in line with the venturi throat.... straight down the throat and into the crank hole. Also, the spray bar 'hole' must be centered in the throat... that may take a small shim outside the venturi where the nuts tighten the assembly, and will adjust the spray bar left or right.
Another thing you wrote was in question of the tank to the spray bar. For CL, center of the tank should be center of the spray bar, as I was taught. For RC, center of tank should be 3/8" lower than the spray bar [ to stop syphoning].
Back to breaking in... the cast iron and steel cylinder/piston needs lots of breaking-in. My old Enyas still run great, but not too powerful. They took forever to break in. Try more nitro [25%] and more 'break-in'..... Last chance, as they say... before it gets sent back!

Mr Cox

I actually have two of these sad little engines... (RC version)

First one was simply to loose in the piston/cylinder fit and I've had exactly the problems you describe. The engine only runs at a very rich setting (one click on the needle between running and dying), probably it relies on the extra oil to get any compression at all. Mine is not really broken in yet but I really doubt it is going to improve. I think the material in the piston is very important for steel/iron setups and the material choosen by the Chinese might just be from old farm tools. Supposedly the iron piston can grow after heat treatments and the porouse surface might also get filled in with material from the castor oil, but so far it doesn't look very promissing...

I got a second engine due a mixup with the dealer were they endid up owing me money, I didn't hear from them for over a month. I then managed to track the owner down on his private mobile phone and they then refunded me with parts... Long story but the second one is actually a lot tighter but this seems to come mainly from an oval piston/cylinder, I will have a go at breaking this one in too, but I can't help feeling that Andy's solution with parts from the wasp is the way to go. Now I just have to find a dealer that will ship wasp parts outside of US...

gcb

I think you mentioned that it originally had decent compression when flipped.

You may be losing air seal between the needle and the spraybar or between the spraybar and the venturi. Try adding some heavy oil in those areas just before starting. If that is the problem, some blue lok-tite will fix it.

The conrod fits could have been loose before or you may have ruined it by running too lean for too long. When you run too hot on an iron/steel engine, one of the results is extreme wear on all moving parts.

John Brodak is good about these things and may replace it. In all honesty, you probably imposed some extreme wear while breaking it in improperly. You should try to NEVER run an iron/steel engine too lean. Whether you get a free replacement or buy a new piston/cylinder and conrod, you now have some additional information on how to handle the new or repaired engine.

From what I've read, and this may or may not be true, the Brodak .049, although basically a CS engine, has mods specified by Brodak specifically for CL use. The RC one is different inside (iron/steel vs ABC).

BTW, I answered some other stuff on your CL posting.

George

Mr Cox

Just to clarify, as far as I know the CS/Brodak MkI is iron/steel in both RC and CL version. There is a more recent MkII that is ABC and it is CL only.

combatpigg

My Feedback: (3)

The only way I know of to thermally expand metal and lock that dimension in is by heating the metal to a point where it becomes non magnetic and then quenching. Running the engine at normal operating temps wont do it. 90% of the parts break in occurs in the first couple of minutes after the first fire up. You can monitor the wear in process by examining the exhaust residue as the engine runs. If the engine exhibits little or no compression intially, there is very little chance that spending hours and hours running it on the bench will improve things. Lots of bench running can relieve tight spots, but your time is better spent relieving those tight spots by hand lapping.

No amount of running will correct the basic problem here, the iron piston is too heavy.

The fits in the engine I had were good, there was ample compression made...but the engine topped out at 13,000 with a 6x3 and would not do any better than the weakest $7 Surestart that I own. I consider the time I spent on this engine a complete waste, and that is something that you can never get back.

If the ABC version was much better, wouldn't this forum would be chock full of glowing reviews and numerous Brodak .061 project threads by now?