Pros/Cons Brodak .40

[dankar]

I have two of these /one used other needs finishing breakin. From what I have seen and heard seems like a decent engine. I have a framed Still Stuka and like weight and size of this engine.
Cheers,Dan

[Jim Oliver]

Hi Dan,

Not sure if you are asking for comments about the B40 or just making your own observations.........

We have seen and used several B40's and B25's locally; break them in per the instructions and enjoy!!

My first 40 is on a much abused (read often crashed/repaired and heavy (47 oz.)) Oriental and just keeps getting better.  I have been using Powermaster 10/22 with Zinger Pro 11x5, 4 oz. metal uniflow, 60 ft. eye to eye.

I have noticed that nobody is making any money "Fixing" the Brodak 40 or 25.........must be a message there.

Cheers,
Jim

[dankar]

Hi Jim,
Good point and well taken. Thanks for input.
Dan

[Andrew Borgogna]

Like you I have two B-40 one very used and the other new in the box.  My good friend Larry Renger also uses one in his Brodak Smoothie.  Like others have said break them in according to the directions and use 11x11x10 mixture and run great.  I too have a Stills Stuka Stunt, my guess is the B-40 might be a bit too much remember that plane originally flew on a .29.  I fly mine on a Fox .35 and it has plenty of power.  But then again the B-40 is light and it would provide plenty of reserve power.
Andy

[Just One-eye]

Howdy, Andrew!

Don Still was the first model plane flier with a national reputation who I met, and I used to try to fly the same way he did, but just didn't have the steadiness to match him.  He had three variations on the Stuka, with the second and third (almost the same, really) both being designed around the Fox 25 three-bolt stunt engine.  The very first Stuka was closely related to the Barnstormer design, and is pretty much the one that was kitted (although if I recall correctly, the Ambroid kit's cowl looked a lot more like the later versions). 

Ambroid's kit was a reasonably good one for that time period, and I built a couple of them in the early 1960s.  They didn't suit me very well, though, and Skylarks did do so. 

[Elwyn Aud]

Lew Woolard had a B-40 on a Ringmaster and it didn't seem to be overpowered.

[Larry Renger]

As Andy said above, I fly the Brodak 40 in my Smoothie.  Lovely engine runs once you get the tank mounted correctly.  Stan Tyler and Antone Kephart are big fans of the engine too, and they fly Expert.  As noted, there are NO modifications required, and it appears that only those who don't follow directions have problems.  The Smoothie flies on 65' lines, pulls well, and corners hard.  Prop is an RSM 10x6 with added undercamber.  Fuel is 10-10-10 currently, though I have used 15-11-11 in the engine in the past.  It does the full classic pattern on 105 cc of fuel, or roughly 3-3/4 oz.

I probably have a hundred flights on the engine with no sign of wear.  I do use an electric starter (I LIKE my fingers!), so unless I flood it (easy to do, actually), I get instant starts.

[Garf]

I bought one when it first came out. I had nothing but bad luck with it. I couldn't keep it running and ended crashing it a number of times. It has been to Scott Dinger twice for welding, and to Tom Hampshire twice, all to no avail. I've simply given up on it. It runs great on the ground, but won't hold a setting in the air. It is now at the back of my engine drawer, probably permanently.

[Larry Renger]

My experience has shown that this engine is totally unforgiving of fuel foaming.  I had terrible luck with it until I got the tank mounted in foam rubber, just right.  Then perfect runs.  In the latest round of problems, I found congealed goo inside the needle assembly.  Cleaning that out solved the probem.  As noted above, the engine just sips fuel.  As such, the needle setting is pretty closed.  This makes fuel supply critical.

Once you provide the engine with a reliable fuel supply it will run in the air just as well as on the ground.

[Garf]

Once you provide the engine with a reliable fuel supply it will run in the air just as well as on the ground.

I tried every trick I know, and i'm not exactly a beginner at this. It would run rich at the start of a flight, it would go dead lean halfway thru the flight, then back to rich for the last of the flight. This happened with several types of tanks. The only thing I didn't try was a pacifier/bladder tank. I have never even heard of an engine doing this.

[dankar]

My reason for asking is that I have a Bowman Hybrid McCoy .35 and a T&L Hybrid .40 Mccoy. both use Red Head Bottom ends and Series 20 top ends with custom Bowman rings. I don't want wind up as I have seen this with OS Max .35S engines. I make my own mufflers from Du Bro muffler stock. Work as good as any muffler I have seen. Thanks for replies.
Cheers,Dan

[Andrew Borgogna]

Oh Larry does this sound kind of familiar?  Larry's engine would start out right and then go rich and I mean very rich late in the flight.  I remember telling Larry I had never seen an engine do that.  We tried everything, finally we took his engine and put it on my Cardinal and guess what it ran perfect.  The problem was not the engine but the fuel delivery system.  He finally removed everthing involved with storage and transportation of fuel to the engine and replaced it, and then the engine ran perfect in his Smoothie.  To this day I do not understand the problem, but I know the problem was not in the engine.
Andy

[tom hampshire]

Hi Andrew - Might it have been a leaky uniflow line inside the tank?  A small crack which is submerged until late in the flight, and than uncovered, can destroy the vacuum in a uniflow tank and richen the mixture.  The only other cause I know of is exhaust gasses flowing over the tank itself.  Heated fuel has less viscosity, so the needle flows more fual and it richens up.  Any help?  Tom H.

[Alan Hahn]

Another thing to watch out for is the front end of a profile. They all have resonances, and if your front end resonates where you want the engine to run, tough luck! This can also change with time as glue joints weaken. I had to add a cowl to my Primary force to get a good run (wasn't even using a B40 in this case). This stiffened uo the front end and moved the resonance to higher frequencies. A resonance can cause the fuel to foam in the tank and drive you crazy, because you may see nothing on the ground when the engine is loaded. However when you take off, the prop load drops, the rpm's increase, the resonance is hit, the fuel foams, and it's off to the races!

[John Sunderland]

 The guys in my neck of the woods have been using the B40 since just after they were introduced. We live three hours due west of Carmichaels in Columbus, Ohio. John and Buzz came up to our contest the first yearand gave us an engine for the raffle. Several contestants were already using them. Later production runs have been better quality.

 One pro of the B40 over the Fox was lack of a burp after a hard outside corner.
For my purposes on a smallish profile classic it has plenty of poop, easy to prime and requires minimal needle fiddling from one season to the next! A sport flyers dream motor. Just don't try to power a pig with it. I don't overload it with prop either. I run a 10/4 TF Powerpoint and a tongue muffler on pressure around 9800 rpm. Consistant from start to finish with classic run characteristics. 

[Robert W]

I find this thread interesting, because I have a B40 that is pron to going rich late in the flight on an AFR Nobler. The facts are that the first B40 I had in this Nobler ran very well in the 4-2-4 mode, I removed it because I wanted a reliable motor for the Ares I was building. The first motor still runs very good in the Ares. I broke in the second B40 per instructions and installed it into the Nobler same fuel system that worked well with the first motor. I put the same prop on and was expecting the same run, but it would go rich last half of flight. A new fuel tank did not solve the problem so I went to pressure and a wet 2 run with a different prop and got very consistent runs on this setup. I do not remember the first motor acting like this in the beginning, but then I did start flying it in the beginning with lower pitch props in the wet 2 mode before switching over to the 4-2-4 run. I am thinking that this motor may just need more break-in before it will perform the same as the first motor.

This motor can be a knuckle buster when first breaking in, but after some time the starts get much better. I really like this motor for the classic designs and have bought two more for future projects.

[Clint Ormosen]

I only have experience with one Brodak motor so far. I have it my JVL Chipmunk and the engine has been great so far. Nice 4-2 style run with an 11-5 BY&O. Uses 4 1/4 oz for the pattern. Steady run throughout the flight with a metal uniflow tank.
The only drawback so far is that it's not usually a one flip starter.

[Larry Renger]

Well from my standpoint, I had the exact same problems with the Brodak in the same airplane when it was new and when I had freshly recovered it.  Both times, re-mounting the tank with foam cured the run.  It was, and again is, a flawless 4-2-4 break.  Other than the above mentioned later issues with glop in the needle, the engine has NEVER been the problem.

[Garf]

The first batch of B.40's seemed to not do too well as a whole, but all subsquent batches run fine.

Thats what I get for buying one of the first batches.

[dennis lipsett]

I have several of the engines and the favorite is one of the first batch. I didn't follow the prescribed break in in any way and it is a one flip starter, consistant runs and cheap on fuel. It didn't happen overnight though and I did run some strange stuff to get it to settle down. The best props for the engine in question are thunder Tigre props. Cheap, balanced, and dead on in pitch.
dennis

[Garf]

I guess you got lucky.