bullittman281

Hello,
Bullittman here. My first post. I need some help dealing with a brodak .049 MKI engine and the Baby Clown plane. The biggest problem though 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

Falco250

Hi Bulittman,
Please post your message on the "1/2 A" & "1/8 A" airplanes forum also. Members there have a lot
of experience with 1/2 A sized engines like yours and will provide you with plenty of advice quickly.
You could also do a search on "Brodak .049" to see what comes up (use advanced search).
It sounds to me like your engine needs further breaking-in. Look at the ABN/ABC procedure
on the MECOA FAQ web page: http://www.mecoa.com/faq/index.htm
Hope this helps you, Falco250

bullittman281

Hello,
Bullittman again. Thanks for the reply. That link has lots of helpful info. I' also posted my problem on the 1/2A page. After looking at the link it looks like I need to run the engine a whole bunch more. This weekend I will mess with it some more. The weather is sumposed to be better but we will have to wait and see. Once again thank you.

Bullittman

gcb

Bullittman,

I do not have a Brodak .049, but the symptoms you describe fits an iron/steel piston cylinder. If that is the case, try running it for a series of one or two minute bursts, followed by five minutes of cool down. This is called heat cycling. Keep it on the rich side at first, turning the needle a couple of clicks leaner every other run. If at any time it starts to slow down (sag), stop it, let it cool, then start a few clicks richer for a few runs.

While you are running it a bit rich, feel the bottom of the crankcase at the crankshaft. If a crankshaft is fit too tight or a little rough, it may be over heating.

If the engine is fit tight, you may find that performance continues to improve over the first hour of running.

George

Falco250

Hi Bullittman,

You could search for "Brodak .049" on this other CL Forum: http://www.clstunt.com/htdocs/dc/dcboard.php
There are numerous threads on this engine.

Your engine is supposed to be produced by CS Engines: http://home.earthlink.net/~whizzz/welcome.htm
as a Beginner Engine G049p. This site mentions that it is ABC type, but I don't know for sure given that
other members beleive it is iron piston / steel liner. I guess you could try to check with a strong magnet
against the cylinder or piston.

Falco250

Falco250

Here's a product review for the Brodak .049 engine with comments from the Brodak tester and designer:
http://www.clstunt.com/htdocs/dc/dcb..._id=940&page=3
It seems the Brodak version of the CS engine is Iron/Steel P/L and hence you would have to follow the Lapped Engine breaking-in procedure from the MECOA FAQ: http://www.mecoa.com/faq/breakin/breakin_lapped.htm.
You could increase the oil content during the breaking-in phase. They also mention 6x3 propellor as being the best choice for this engine.

My only experience in 1/2 A is with a COX Babe Bee on which I used a HyperLobby glow head and NovaRossi hot Turbo glow plug. The plug had to be screwed in tightly to eliminate leakage. You could use heavy bearing grease or liquid teflon pipe thread sealer to seal the plug threads and possibly improve compression, and avoid any potential plug seizure. Also the plug length (size) should be selected so that the bottom glow element end is flush with the apex of the glow head chamber. A hot standard glow plug is probably best with 10-15% Nitro and your CO higher elevation and cooler temperatures.

You can upgrade your current Brodak head and standard glow plug setup with the Nelson head and glow plug mentioned in the forums. See this current offering on eBay: http://cgi.ebay.ca/ws/eBayISAPI.dll?...MEWA:IT&ih=017

Falco250

scott17

The guy in the post referenced above is Bob Zambelli.He is a really great guy! You should contact him and he will get it taken care of. I had the exact same experience with the same engine and Bob replaced it after checking it out and the new one operates exactly as expected. BIG difference!!! Never could determine exactly what the problem with the first one was......

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 hour 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 differnt 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 Ii 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 went 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 never 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 11.5 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 dont know if this fuel is too hot or not for the Brodak. It ran noticably faster though. 14K RPM untill it built some heat then 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 6X4. I'm gonna keep running it and see if things improve any.

"The Brodak .049 sport engine design criteria was this:
14,000-15,000 rpm on a 6x3 prop running 10% Nitro Fuel. Use a Standard Long Reach Glo-Plug and hand start.
The engine meets these requirements very well. And yes, the engine is
an updated version of the CS .049 Sport engine. Some of the early
CS engines were ABC P/L combinations. The Brodak engine is an Iron/Steel
P/L assembly. They require some break in time. But they Hand pretty easy
after they are broke-in. The engines I tested run very well on a 51/2x3 prop turning it over 17,000 when broken in. On the standard 1/2a racing prop is ran in the low 24,000 rpm range(which I do not recommend)." Bill Hughes

I wish mine ran like that! If it doesn't improve with some more time I'm gonna contact Brodak or the guy scott17 mentiond. It is getting easier to get running but the power doesnt seem that great. I'm assuming the lack of air at altitide works the same on both the motor and the prop so the rpm shouldn't change that much with altitude. Could be wrong though

gcb

ABC type and iron steel DO NOT run the same way. An ABC (ABN, etc.) is more tolerant of mis adjustments. If it runs too lean, the brass sleeve will lessen heat effects. An an iron/steel runs too lean, the piston expands faster than the cylinder, greatly increasing friction that can cause thermal runaway which CAN ruin an engine. Fortunately, small engines are less affected than large ones.

Starting and running does NOT break in an iron steel as much as the heat cycling where it reaches operating temp and is then allowed to cool down. Heat cycling relieves internal stresses and allows the parts to be polished with minimum wear.

From what you say, you may be beyond this. DO NOT run it so lean it slows down. Open the needle until it starts to drop off on the rich side of peak.

The ideal setting for running at peak is to approach from the rich side and adjust until it peaks when actually flying and the prop is unloaded.

Your engine, your choices.

George

gcb

Forgot to address the spray bar question. USUALLY, the spraybar has the hole to the rear. Rotate it just enough that you can not see it and you should be good.

Actually, it should run OK if you just can't see the hole, but there is often a "sweet spot" where it works best, and that spot is often as described above.

If you contact Bob Zambelli, as someone suggested above, he could answer correctly. He helped with design and prototype of the engine.

George

bullittman281

hello,
I put a Cox shure start off of my free flight Cox heli on my baby clown so I could at least go fly it. The cox engine worked flawlessly and the airplane flew!. It flew well. I'm impressed. It was a bit draufty this morning leading to a couple of tense moments but the plane survived. Dont underestimate getting dizzy. Its far more pronounced that you'd expext! I have a question though. Whats to proper tecnique for mounting stunt wedge tanks? CA glue obviously isnt the answer cause it fell off on, we cant really call it landing, recovery. On the photos i've seen it seems to be held on by rubber bands or something but I've never found a description of the mount. Any thoughts?
gcb, THanks for the input. What you describe is how I now have the spray bar set. The hole in it is off set from the center. Its not possible to add shims or anything to center it. I don't know if this is a problem or not, just an observation. How does the brodak Fuel draw compare to a cox reedvalve? My cox shure start is insensitive to changes in the realation between the height of the fuel and the the spray bar. With it mounted on the airplane I can point the nose strait up or strait down with no ill effects. My brodak just rolling the airplane to the outside 45* is enough to kill it. Normal or not? I dont know. Thanks for your input.

Bullittman

gcb

Bullittman,

You are correct about the CA...CA remover is usually nitromethane.

Most use rubber bands for a simple arrangement. You can make more elaborate installations like hooks for rubber bands, etc. Many use a piece of foam between the tank and the fuselage to somewhat decrease vibration in the tank. Installations for larger planes often include means of adjusting the tank up and down to insure a more even run between upright and inverted running. I would stick to rubber bands for now.

If the hole is offset on the spraybar too much it may cause a problem. I'd ask that question when you contact Brodak's Monday. Perhaps it is normal for that engine, but the running characteristics is not.

The Sure Start is hard to beat...especially for the price. You can mount it sideways so the fuel line is to the outside for easier tank installation. It does not matter whether the cylinder is pointed inside or outside the circle. Many aim it outsde for balance, but inside would protect the needle. Your choice.
I have some Sure Starts.

Good luck,

George