Brodak BE-1265 049 Bluehead Break-In
 

First Day (1st): (6x4 wood prop)

Fuel: Nitro 10%-20% & Lube 18%-24% (65-castor:35-synthetic mix) & Remainder Alcohol
a) engine needle valve needs small spring (use Cox 09) for friction to prevent drift, small drift induces engine RPM oscillations (or small RPM accel/decel) – RPM oscillation leads to engine stop
b) use 2oz fuel tank for each separate start/stop run-cycle (thermal heat/cool cycle); first two (2) tanks, engine would not remain running – repeat restarts required – much needle adjustment required – suspect cylinder overheating – also, dark grey engine assembly lube sprayed from non-muffled exhaust port – run with continuous applied glow power – needle set to 1 ¾-to-2 ½ turns open – applied electric starter (4oz fuel burned)
c) third (3) tank – engine run continuous from full to empty tank – normal break-in run with continuous applied glow plug power – needle set to 1 ¾-to-2 turns open – applied electric starter (6oz fuel burned)
d) fourth (4) tank – engine would not remain running – repeat restarts required – much needle adjustment required – suspect cylinder overheating – exhaust gas normal light grey-to-clear in color – continuous applied glow power – needle set to 1 ¾-to-2 ½ turns open – applied electric starter (8oz fuel burned)
e) fifth (5) tank – engine run continuous from full to empty tank – normal break-in run with continuous applied glow power – needle set to 1 ¾-to-2 turns open – applied electric starter (10oz fuel burned)
f) required four plus (4+) hours to complete (a)-thru-(e) above; quit for the day – more break-in runs later
HHHHMMMMNNNN ...

That sounds very excessive. Have you called Brodak? You may have got a bad one - much too tight.

paul

Thats sounds like the CS .049 engine, also named Brodak MkI?
If it is tight you are lucky ;)

They were really poor in terms of quality, I have actually flown one of my .061 engines but it wasn't exactly straight from the box...
Here is a thread on the .061 RC version from that time; http://www.rcuniverse.com/forum/1-2-...i-give-up.html

Here are a few things to check for:
- use a 6x3 prop or smaller
- use 25% all castor fuel
- the compression ratio is too high, I use 3-4 head shims on mine
- the conrod will rub hard against the backplate, along the full length of the conrod (needs a spacer on the gudgeon pin to prevent this )

Engine Operators, I read the CS 061 ... I Give Up ... posts. As a mechanical engineer of many years experience, the primary problems with manufacturing quality (i.e. materials & workmanship) results in the following;
a) engine non-operation or poor operation (low RPM & low Torque/Hp & unsteady RPM oscillation)
b) short operational lifecycle or poor product durability
If an engine is able to turn a defined propeller at the defined engine RPM ... then the engine is NOT failing performance; regardless of its appearance.
Unless the engine seriously fails to operate, poor manufacturing quality primarily affects the engines durability ... this includes porous casting material. "Bubbling" castings do
NOT directly affect performance unless it is extreme ... similar to a metal foam "fluid filter" condition in which required flow pressure cycles cannot be maintained during operation.
The gas flow (and associated pressure cycles) through an engine is far to fast for small amounts of leakage to notably affect performance ... does the engine produce propeller RPM
or NOT ... is this RPM operation steady or NOT ... this is primary engine performance.
Fuel consumption and product lifecycle durability are lower order operational characteristics that do NOT measure primary engine RPM performance ... which is what is required to "FLY." As for "variable throttle" operational performance concerns, only fuel injection and/or sophisticated carburetors can deliver such variable engine RPM performance with stable control, high power output and fuel efficiency (sfc). Sooo ..., just how much weight and cost is one willing to endure? Only operators (i.e. customers) and engine designers can answer these questions directly!

BE-1265 Second Round of Break-In Runs - no real improvement ...
Past weekend ran engine again on 10%Nitro/20%Lube/Methanol - engine would start OK but would not remain running ... longest run was about 1.5 oz.'s of fuel ... many shorter runs between 0.5 -to- 1.0 oz. of fuel. The engine would start up slowly ... then increase RPM to somewhat normal steady operation ... GOOD ... then slight RPM oscillations during the operational run. I'm using a 2 oz. tank.

It appears to me that the engine venturi inlet suffers from too little fuel suction draw. When the tank is full ... there is some positive fuel pressure by gravity to the venturi inlet (i.e. needle valve). When the tank fuel level drops much below the needle valve ... the engine "seams or appears" to struggle for fuel suction to the needle. It seams to experiences a form of fuel starvation ... then the RPM slows and the engine stops .... no fun! Is an engine "tear-down" in order to examine the internal workings of this engine ... hhhhmmmmnnnnn! Or is it beyond help???

Sounds like it needs to run on pressure. I am guessing there is no muffler to tap from. That leaves a bladder which seems like a waste of effort on a low performance motor. Otherwise, plug the carb to a smaller size. I have had some leaky taiwanese (T Tiger) motors that needed more oil and the smaller ones like nitro. 2 oz. is a big tank for an .049, so it would take some effort to suck it uphill unless it is revving kind of high.

On my engines I've had problems with swarf inside the black plastic part where the fuel line connects. This comes from when they drill the hole through it (I guess). You'll need to remove this swarf and also check how well the hole lines up with the grove in the brass part. On my engines this groove was too shallow and slightly miss-aligned with the hole in the plastic part. If you have a lathe you can easily increase the depth and width of the groove, otherwise I guess one can do it with a small file as well.

The low-end is way too rich as they didn't put any type of compensation on the low-end. You can add an airbleed hole though which will improve the throttling. Here is a short video of one of my engines;

The above is for the RC version, the CL might be different, if that is what you have.

The stock compression ratio is actually very high, I'm running 3 head shims in mine for 10% nitro fuel (and 20% all castor). So if your engine is over heating that's one more thing to try. You also need to use a smallish prop, the APC 5.7x3 is a good match and I wouldn't recommend any larger loads than that.

BE-1265 Break-In Completed - Results
 

OK - I have completed the break-in by performing the following;
a) cleaned and reassembled back cover plate (backplate) - noticed some 0.002-0.005 in. wear in backplate from crankshaft rod/pin assembly (could be the result of repeated applied pressure to spinner/crankshaft via electric starter usage)
b) used 5x3 nylon prop and "short" glowplug (reduces internal cylinder compression)
c) reset NVA to 2 turns open for start => then reduce to 1.5-1.75 turns open for run; using 5x3 nylon prop - engine ran mostly stable and consumed full 2oz tank (YEAH!)
d) changed prop to 6x3 wood & repeated above procedure (c) - engine ran well for 1oz and then required needle valve adjustment to retain HI rpm (it seams that large props and associated reduced engine rpm limit fuel draw (suction @ venturi) after the fuel level decreases below the NVA - working against gravity)

Conclusion - the engine will now run a full 2oz tank on a 5x3 nylon prop - it suffers from low suction at the NVA - it likes lower compression and HI rpm ... plus HI levels of nitromethane ... for stable engine operation (stable rpm) - Cheers, Flypast111

What rpms are you seeing?

On my engines the conrod moves too far back and wears against the backplate. With time the initially round conrod will have now have a flat part facing the backplate, and the backplate has a distinctive wear from the conrod position from about TDC and 45° down (in the direction of the running engine). I solved this by placing a thin, and bent, washer on the gudgeon pin, between the conrod and the rear part of the piston. There is still enough room to easily slide the conrod over the crankpin during reassembly.

With several extra head shims it should be able to handle a little more prop load than the 5x3, but a 6x3 is likely around the highest load (cox props also have larger blades compared to APC for instance).

Why do you say that it has low suction at the NVA?
1.5-1.75 turns on the needle is not much compared to other engines. But if you have a "suction problem" my guess is that it is not in really a suction problem but rather a fuel delivery problem. All of my engines (four red head .061 RC and one blue head .049 RC) have had the issues with the plastic nipple that've described earlier.

CL Venturi Suction - NVA Adjustment
 

Non-exhaust pressure fuel delivery to a CL venturi requires that the engine generate sufficient vacuum at the venturi spraybar to "suck, or draw," the fuel into the engine. When a properly placed fuel tank (i.e. half of fuel level above the NVA and half below the NVA) is filled with fuel, gravity assists the first half fuel delivery and works against the second half remaining fuel delivery.

For a CL engine with sufficient fuel draw or suction (i.e. vacuum), the engine will generate adequate vacuum at the venturi spraybar to draw fuel into the engine without additional needle valve adjustment to sustain HI rpm operation. In this case, the 6x3 wood prop application did not achieve such a result. Additional needle valve adjustment was required to sustain HI rpm operation for the lower half remaining fuel to be consumed ... else, the engine would likely stall (or at best run slowly for the duration). On the other hand, the 5x3 nylon prop consumed the entire 2oz tank without further needle adjustment.

Further, I agree that the "fuel delivery apparatus" is also key to achieving adequate fuel delivery. So, close attention to the entire fuel delivery system is required. In other words, an improperly placed fuel tank or a long fuel line will also impede fuel delivery.

Cheers, Flypast111

Chasing the needle through a run can also be an indication of overheating. You could try lowering the compression ratio and see if it improves. If it is really the fuel draw, you can add a pressure nipple to the rear part of the stock muffler or put a restriction in the ventury, a thin-walled aluminium tube with a snug fit is all it takes.

Overcompression - Maybe or Not
 

This 049 Bluehead engine may be over-compressed (???) - only head shim application and further testing could show real results. However, for RC flying (due to variable engine throttle), application of fuel tank pressure is noted to be common practice. In control line circle flying ... it is not common. Uniflow tank set-up is the "common" practice due to centripetal acceleration & direct freestream "pitot" aerodynamic pressure application to the tank.

Since I now have a "clear" demonstration of this engines expected performance, any further testing will be performed "in-flight," rather than on a bench set-up. So, I am ready to proceed to the flying circle for further engine operation ... and the fun that goes with model flying.

Cheers, Flypast111