[TailTwister]

Wisconsin weather is 40 degrees, and pretty. The fuel was 2+ year old 10% Cool Power. The plug was some cheapo that I keep for run in. The OS 25 LA hit 12,300 rpm (stable) with the 10x3 APC prop. I could pinch to 12,500 to 12,600 peek.

The low end screw needs the usual stretch the spring out treatment.

After a few tanks, I'll go to Wildcat 20% fuel, and let it scream a bit.

Anybody got an rpm guess for that?

 

[PaulSwany]

I put a OS 32 FSR carb on my 25 LA... Man does that wake it up!!

 

[TailTwister]

Is the FSR an airbleed? I'd be up to a change if I could get a nice fuel metering low end needle...

Airbleed carbs need to be outlawed.

 

[PaulSwany]

NO..... Air bleed carbs SUCK!!! The FSR carb is a dual needle carb.. The .25 fsr carb is a direct fit and it rocks!! You have to turn down the .32 carb.

 

[TailTwister]

I do no have the equipment for turning, but the 25FSR carb is a maybe.

I just ran the third tank of fuel through the LA. It was the 20% Wildcat. Strangely, I didn't really see any real increase in rpm. I could get about 200 rpm more, but I'm not sure I wasn't just turning the needle a click leaner than before.

There was marked improvement in transition and idle. It also sounded a lot cooler.

I guess break in is more important than nitro at this point.

I'll call the LHS and see what it takes to find a 25 FSR carb these days.

 

[PaulSwany]

I've also seen guys use os 40 fp carbs..... They are the air bleed type... but they have more capacity....

 

[TailTwister]

If I'm switching, it will be to a two needle carb. I'm more interested in user friendliness than power at this point. If I was focused on power, I'd toss the LA at a garbage can and go get an FX. At 12,500 rpm, the power is OK, but setting the airbleed is a pain.

If I can remember, I'll call the LHS tomorrow.

 

[Gordo]

Razorback told me I'll get great power from my old .25FPs with the .40 FP carbs and MCP. ever seen that? I'll try it I guess. Irvine .25 is toast.

 

[TailTwister]

I called the LHS, and they said that getting a part for a 25 FSR is probably not going to happen.

Does anyone know of another "drop in" replacement that is a two needle carb?

After flying it today (see the review forum), the Mini 3D is a keeper. The 25 LA had good power, but the low end still scares me.

 

[Gordo]

I put the .40 fp carb on the .25 fp today, on the Taco. It wasn't quite as strong as the Irvine used to be but it was close. Hovered it fine with some pull out. Keep in mind my taco is about 2#10oz. I know it's an airbleed transition, but it only took a few minutes to get the low and transition just great. I was impressed. I'll get a MCP this week and see what it does.

 

[TailTwister]

I may let the LA just go. Hell, I should have got the FX to start with, but I was shooting for a 2 pound Mini. I hit 2 pounds 2 ounces like everyone else. Wayne says that they did one with the FX, and no alterations to help CG, and it flew fine. My Rx and Batt are under the trailing edge of the wing, with a CG of an inch back from the spar. I could easily take the weight (and CG shift) of the FX.

For the record, the 25LA with some junk fuel had plenty of pull, even on only 3 or 4 tanks of fuel total run time. I think after 10 or 12 tanks, it would be a powerful combo.

If the airbleed wasn't such a pain, I'd keep it. My low end screw is all but taken out of the plane, and I'm now going to enlarge the air bleed hole a tad to see if I can get more air in there.

Again, air bleeds suck!

 

[TailTwister]

Well, after about 2 hours of work, the LA has a stable idle of 3,400, and an increase from 12,500 to 12,800 rpm on top.

I started by enlarging, side to side, the air bleed hole. It's almost double wide now, but I finally did hear a lean sound, and began to work the screw back into play. During the experiment, the low end screw actually fell out once and the engine ran better that way. I was a bit pissed, but it gave me the guts to cut into the carb.

I bored out the carb body and barrel too. I figured my warranty was gone and the carb would be OK or just plain junk, so what the hell.

From 3,400 to full, the transition is an effort, but after a full minute at 3,400, it never failed (I did this like 12 times over 3 tanks of fuel) to make the jump. From 4,000 rpm it is much quicker. I have to remind myself that an APC 10x3 is no lightweight for the LA, and that a small engine just won't always idle like my Saito. I'll fly with the higher idle, using the 3,400 for taxi and final.

It was a pain, but it's done.

 

[Gordo]

try the 9x4 MAS (but paint it grey so nobody knows!!!) That is the only prop I put on my .25s on the PBFs I was running. The .25fp on a 2# plane was great. The Irvine took the 10x3 fine, but none of my others did.

 

[TailTwister]

I don't really like MA props at all. I have an APC 9x4 that I'll try if the LA doesn't really like the 10x3. At this point, I think the 10x3 will be OK. I might not have the transition speed I want. Like I said, it never failed to transition, it just didn't like it much. I got the old "uhhh-uhhh-wahhhhh" sound.

Maybe I'll try a Top Flight Power Point 10x4 or 9x4 too. They are much lighter than the APC props. As long as the thrust is close it will be OK.

 

[Gordo]

I don't really like MA props at all. .

Don't like 'em? Hell, I HATE them :x !!! That's why I said paint it grey!! But for some reason it seems to do it for the lighter .25s, at least for me. The woddys I tried sucked really bad, APC 9x4 was fine but I don't think it had near the thrust the MA did (did I say that?). :shock:

If you do find a good one, let me know. I love trying new props. I end up giving more away than I end up keeping, but it's just what I like to do.

 

[TailTwister]

Although I have not yet tried one of those "other" props :roll: , I did work on my idle a bit today. I can idle down to about 2500 now. I still think the darn thing is loading up, as after a minute or so, it starts to sputter. I jiggle the left stick and it comes back. Rpm drops to 1900 or less when it's sputtering. I pinch the fuel line, and the rpm comes up. That's pretty good proof of loading up if you ask me...

I don't know my bore diameter, but rpm stays at 12,800 8) now at full power (10x3 APC).

My airbleed hole is easily twice as wide as stock, and slightly larger in height. The screw is still backed out enough that the threads are not visable in the airbleed hole at all. Why the hell is it loading up?

How low of an idle should a 25 size engine have? I thought 3,000 was good, but the guys on RCU say 2500. One guy said 2000? :shock:

 

[Gordo]

I wouldn't expect 2k on one of these guys. I'd be pleased as punch with 2500 and like you said, if it had to be 3k to keep it happy I wouldn't be surprised. My Irvine idels real low, about 2400 if I remember right, but none of my OS .25s are that slow. I'll check later to see what the .25fp on the .40 carb is doing.

 

[TailTwister]

Thanks for the back up on the 2K rpm. The guy I was talking to was telling me how well they idle way down. My YS 91 will idle at 2K all day long, but a 25LA? I didn't think so.

At 2,600 I'm OK with what I hear, but I like 3K better. I'll just pull the trim tab back a few clicks to land. I don't usually fly too much at idle.

He compared the 25LA to a fine Swiss watch. I never saw a swiss watch run better with a couple of it's parts lying on the ground. :?

I've had enough bench testing, I'm ready to go flyin' again!

 

[Gordo]

He compared the 25LA to a fine Swiss watch. I never saw a swiss watch run better with a couple of it's parts lying on the ground. :?

!

Ok, that's way over the top!!! I love my .40 FPs, but even they are not a swiss watch! Now my saito .91, that's a FINE piece of machinery!!!

 

[TailTwister]

I feel like that way about my YS. It was, last season was the last time I ran it, 100% reliable. It never failed to fire within two (hot) flips, and it never failed in flight. NEVER! I set the needles once, and never touched them for the rest of the year.

Now, why can't my $60 LA run like that?