I think the LA .46 and likely .40 do the 424 break thing. The BB ones don't from what I have been told by qualified people. My FP .40 didn't but I only have one flight on it and I think it was just me setting it leaner than I should have. I don't consider myself as knowledgeable in the stunt thing.

Originally Posted by aspeed

I think the LA .46 and likely .40 do the 424 break thing. The BB ones don't from what I have been told by qualified people. My FP .40 didn't but I only have one flight on it and I think it was just me setting it leaner than I should have. I don't consider myself as knowledgeable in the stunt thing.

I think you're right. The last stunt contest, here in S Ca was cancelled. Next one I'm going to make a list and listen to each engine and how it breaks. I remember listening to stunters and each engine has it's own breaking characteristics and sound-kind of like the difference between a hot rod 301 CI mouse and a 350 CI. or a 500 inch rat.
A plain bearing engine would be ideal in this application, reduce weight and radically improve performance! I'm seeing a nice, dialed in OS 46. I'd double the control surface area, use a 1/2 A control horn and matching adjustable pushrod, And then I'd have an adjustable rudder to get it dialed in, and then fix the rudder.

And aspeed, how much would you want this bird to weigh?

I've played around a great deal with FPs in the 25, 36, and 40 sizes, and right out of the box, they simply do not run a breaking style. What they will do, on the correct fuel, is run a "Rich 2 cycle" that managed the same general effect, at a somewhat higher RPM, on lower pitched props.

The fuel need to be "Oily". I can't get the same result with less than 24% oil by volume. My best results have been 50-50, half Castor, half Klotz synthetic oil, and the 40s have been the easiest of the three to find the right needle setting with. I used 10-4 props on the 35 and 40, and 9-4s on the 25s.

The only OS MAX "LA" engines I've had were 25s, and so far, I haven't tried either of those two at a slower speed for a sport or stunt plane. A local dentist in this city was running his LA 25 with a wood 9-6 of some sort, probably a Zinger, on a Streak ARF, and it was working fine for him at a relatively rich needle setting.


Kiwi

I don't know what an ideal weight is, but lightest possible. I would keep away from the small block Chevy on the planes though.

Originally Posted by The Kiwi

I've played around a great deal with FPs in the 25, 36, and 40 sizes, and right out of the box, they simply do not run a breaking style. What they will do, on the correct fuel, is run a "Rich 2 cycle" that managed the same general effect, at a somewhat higher RPM, on lower pitched props.

The fuel need to be "Oily". I can't get the same result with less than 24% oil by volume. My best results have been 50-50, half Castor, half Klotz synthetic oil, and the 40s have been the easiest of the three to find the right needle setting with. I used 10-4 props on the 35 and 40, and 9-4s on the 25s.

The only OS MAX "LA" engines I've had were 25s, and so far, I haven't tried either of those two at a slower speed for a sport or stunt plane. A local dentist in this city was running his LA 25 with a wood 9-6 of some sort, probably a Zinger, on a Streak ARF, and it was working fine for him at a relatively rich needle setting.


Kiwi

Oily. Interesting. I still don't understand exactly what happens when these engines 4 cycle, but it seems to make sense that oily fuel improves the 4 cycling and or break in some engines.

BB or not it does not matter too much. Yes one is lighter than the other one but if you get a stunt motor (that is a motor that has the proper timing for a stunt run) it is up to you to make it run 424. That is something you need to know how to do it. You need proper venturi size proper prop diameter proper pitch proper fuel etc.

Give me a good running Fox 35, McCoy 35 or 40, any variations or an OS 35 S and I'll have that puppy doing the 4 2 4 before you know it. The little experience I've had attempting engines not designed to do the classic CL break to break well proved an exercise in futility.

Originally Posted by RknRusty

You may be able to leave off the outboard wingtip weight with a backwards rotating prop too.

I wish that was the case. I have over 1000 flights with pusher props but they all still require pretty close to the required amount for a given design.

Originally Posted by tigreflyer

Give me a good running Fox 35, McCoy 35 or 40, any variations or an OS 35 S and I'll have that puppy doing the 4 2 4 before you know it. The little experience I've had attempting engines not designed to do the classic CL break to break well proved an exercise in futility.

I disagree a litle bit here.

Most motors will 424 but some are happy 424 at one rpm range others at a different rpm rang, because of their particular timing and porting, you just have to find that happy place and go there. Rpm is not important, the motor run is important. First focus on the motor run, then you focus on speed. If you want to adjust speed you change the pitch of the prop and or diameter not the needle valve.
On the ground run the motor and put the nose up and see if it 424 reliably. That should be somewhere a little below the max rpm use your ears for this and get used to this sound.
In flight notice what the motor does in a loop. If it goes in 2 and does not cycle back to 4 then you do not have enough prop load or it is getting too hot and it has not sufficient cooling. In that case use a larger diameter or heavier prop add oil in the fuel. If it struggles to go 2 and wants to stay in the 4 then the prop has too much diameter or weight use a lighter one (do not take away oil).
When it goes 2 watch what the motor does. Does it scream like mad or it is braking in 2 with authority but not harsh. This is a top rpm issue and it is fixed by the venutri size. Venutri size is like the gas pedal on your car the more you press it the more the air intake opens and allows more air flowing and the motor revs up. So if your motor is too harsh then get another venutri with a smaller hole or steal your wife’s stalking and an O ring and put a few layers on the air intake to restrict the air (this is a good way to create an air filter).
Another way to fine tune this is with fuel. Take away nitro to soften the run. This will not be a drastic change but is more subtle it should be done towards the end of the motor tuning and it can be very useful during travel. When you go fly at higher altitude or lower altitude. Higher altitude requires more nitro because nitro is oxygen. If you go to the NATS at higher altitude almost everyone will go 5-10% more nitro compared to what they are used too and perhaps from 2 to a 3 blade prop too.
I guess you need to know what to do and what direction to take compare to your flying stile likes and dislikes and tune to suit it. Whatever you do keep that motor in the happy place the needle helps a bit but it is not to be abused and the motor must be kept in the sweet spot. I hope I did not bore you to death.
Traian

Originally Posted by aspeed

My flying buddy used an F2D combat with a .15 sized electric. I thought it went good with the 2200 mah battery, but it was a little heavier than a glow. Maybe a 1200 mah would be better. He wants a .25 now. I think the F2D would be better than a Flight Streak, and they are only $50. Just wondering if you use a fuse for the motor somewhere in the circuit? I would assume there are crashes, and LiPo's don't take well to that.

Lipos dont take too well to being launched a couple of hundred of foot across the ground either. I tried that yesterday. The Flite Streak flew excellent. It needs the cg further forward than the instruction, plus the pushrod in the inside hole instead of the middle hole. And I wish it had about another inch of leadout sweep. Besides that its great. Now I apparently need a better battery hold down system. It turns like a combat plane, so its hitting some substantial g's. It ripped my 3/16 balsa box to shreds.

Bob
I knew it would be good for what you are looking for. I want to do that around here with glow but every one is talking 1/2 A and that is just not the same.

Originally Posted by critter1340

Bob
I knew it would be good for what you are looking for. I want to do that around here with glow but every one is talking 1/2 A and that is just not the same.

For some really fast hauling, get an OS Max FX 25 (those pull a Big Block sized Sonic Chicken at around 90-95. Or else get one of the 21-sized hot OS Max buggy motors, and match it to an FP 20 Head (still the same bore, I believe -- I did that to one, got an engine that would almost keep up with one of those FX 25s, just likely to cost too much without a bargain eBay auction).

If someone you know has some Cyclon F2D engines to turn loose of that haven't been totally smoked, those will pull a Streak at 90 on 60' lines.


Kiwi

I rebuild the battery mount with plywood this time. Made a cowl out of a water bottle. It fit perfect...until I got impatient for the paint to dry and put a hair drier to it. It shrank a bit. I've been doing these cowls on my F2D's and they work great. My speed control is inside the planking behind the battery.

Cost must have been the reason why they chose built up instead of solid balsa fuselages when ARFing the venerable Flite Streak

Yeah, its really a better electric that it would be a fuel I think. It is light though. And I've already stuck it in the ground once. (notice the covering in the inboard wing) When the battery shot out at the bottom of an inverted wing over about a foot off the ground, it got tail heavy instantly, over rotated, I over compensated, and hit hard on the nose. To my surprise it just split the covering around in different spots. No other damage.