Locally, I see folks flying the Brodak 40 with the same props used on the OS LA 46 and LA 40 and tuning the same rpm.  Normally, my B40 uses 4 oz. Powermaster 10/22 for the pattern with the Zinger Pro 11x5 at 9000rpm.  Usually, the OS engines require more fuel to fly the pattern than the B40.

Now, I think that the OS 40/46 will probably turn the prop in question (Zinger Pro 11x5) faster than the B40, but  not with the run characteristics shown by the Brodak.

So---my question:  If one had a model that is slightly large or heavy for the B40 would there be some advantage to using an OS LA 46?  If yes, how should the LA 46 be set up? 

I saw Dee Rice fly his stock LA 46 powered R.M. 576 at Memphis but don't know what rpm he ran with the APC 12.25x3.75 prop he was using.

What say you?

Thanks,
Jim

Sure, Paul--the more the merrier!!
I hope to get some answers on this---so far, from my very limited observations, I don't see a power advantage to the LA 46---unless a solid two stroke run is used.
Jim

Well, as long as you're including .46s, my choice would probably be a good, solid ST G21/.46 on a REv-Up 12-5 or RSM 12-6 cut to 11½".  Tough to beat that nice, predictable run . . .

First off, let me qualify everything I say, I am NOT an expert either with engines or flying but I have learned bunchs from those who are, ok, I fly both the FP 40 and the LA 46. which do I like better, well both.
both have their drawbacks and both have strenghts. the FP 40 seems to work well for me on the apc 11.5 x 4 or the 11x4, I generally launch at 9600 depending on the airframe and tank setup and how much it unloads when launching.
My LA 46, I use the 12.25 x 3.75 APC on it and launch at 9700 with either tanks setup or venting, ie muffler or free air. It doesnt do a classic 4-2-4 in this mode, but it does break. I use powermaster 10x22 fuel to which I add 6 to8 oz of additional castor depending on weather conditions. I have found that the FP is very sensitive to load, blade width and weight. I have far better runs with a wood prop that I carve to mtch the APC 11.25  x 4. It is really happy and breaks well. Moost of my stuff uses the stock muffler because of CG issues and I take out the baffle, as well as open up the stinger tip until I think its going to be to thin.My FP in that setup does a really nice break and it is more along the 4-2-4 style than the LA. THe drawback to the FP is that unless you get the motor loaded in its happy place it will  want to go lean sometimes. this is prop critical in my experience. My experience yiours may vary. The LA is somewhat a plug and play with the 12.25 x 3.75 APC and 9700 RPM. However if you play around with props and rpms, you will find that it will vary its fuel consumption DRAMATICALLY with RPM. I am talking a few hundred rpm high and you will be there an extra 3 minutes a few hundred low and you can run out in th ehourglass, ask me how I know, Now I run the APC , set the needle by the tach and fly. dead on consistant. NOw Pat Johnston flies his LA46 with the .272 venturi and a ST needle, same prop, same rpm and he gets the pattern done in like 3.75 oz of fule, mine takes 4 or slightly less, I use the larger stock venturi and a ST needle.
As I said, my experience yorus may vary, also my FPs get a retiming mod to the boost port, I dont block it.

As I have stated here several times before when people ask about engines, props and fuel, it depends on what part of this great land you fly in.  Also the time of the year.  Why do the top guns in Precision Aerobatics put in so many flights at the NATS?  It is because it is not the same as it is at home.   I have an OS FP-35 that flies circles around my OS FP 40.  My OS LA 40 flies great now that I have removed the blue coating that was on it.  Have not gotten the OS LA 46 out of the box yet.  Now to the Brodak 40 I have no complaints of any kind with it.  But, each and every engine I have mentioned has its own prop that works the best.  Have fun,  by the way the fuel I use is standard SIG 10% with half & half oil.  DOC Holliday

To be quite honest, I have not seen a LA 40 run as good as the LA46.  The .46 is lighter, uses minimally more fuel, but does need .018 lines.  That's less of a problem that most people let on.  For me, I agree with Ty: dump the LA 40 and use the LA46.

The Brodak 40 is a very good "stunt 40" in the old fashioned way.  It's definitely NOT a PA or RoJett 40 (or even an Aero Tiger 36) but still a good "40".

I've flown or pitted all of those.

A guy we fly with every week has a plane with an LA46.  It just about drags me across the field trying to hold it back.  The others don't.

My LA40 is a brute but save your 4-pitch prop for stiring paint.  Put an 11-6 PowerPoint on it with 10% Omega or Coolpower - and fogetaboutit.

I run the same prop on the Brodak 40.

Sorry, Doc, can't bad mouth the Brodak 40.........................

Mercenary, Doc, mercenary!      

Cheers, Geoff

I have the B-40, LA-40 and LA-46.  Not flown the LA-40 yet but the LA-46 is set up on the ARF Tutor.  Using the MACs stinger muffler and APC 12.25-3.75 cut down to 11.75.  It just purrs right along.

B-40 is being flown in my son's ARF Primary Force with an APC 10.5-4.5.  We were using a 10-4 but haven't enough flights on the former prop to adequately compare.

All fuel is Sig Champion 10/20 with added castor.

Speaking of weights,

B40 pulls my 49oz Chipmunk easily, even in windy weather. When Windy Urtnowski flew it, his comment was: "I can win contests with this model!". A year after he flew it and many other models later, he still remembers how well the model flew and how EXCELLENT the motor run was.

As has been observed, by some with much more experience than I, no body is making money "fixing" Brodak 40's.

They come already "fixed".
Jim

I have been using a layer of the more open part of the panty hose material---mostly to keep trash out.  I may try another layer or two in an attempt to adjust the run.

Thanks,
Jim