Author Topic: OS LA .46 Best Prop Choice? (Read 7445 times)

Avaiojet · « **on:** October 19, 2015, 10:34:23 AM »

I did my homework on SH.

Looks like the APC 12 x 4 or the APC 12.25 x 3.75 would be an excellent choice for a prop to be used on an OS LA .46?

Or a really good starting point?

Better choices?

Charles

Tim Wescott · « **Reply #1 on:** October 19, 2015, 10:50:44 AM »

More like an APC 11-4, 11.5-4 or 12.25 x 3.75. In my opinion the 12.25 x 3.75 is really too much for the motor, but there's folks that love them so on the right plane it may be great.

Avaiojet · « **Reply #2 on:** October 19, 2015, 01:06:04 PM »

Quote from: Tim Wescott on October 19, 2015, 10:50:44 AM

More like an APC 11-4, 11.5-4 or 12.25 x 3.75. In my opinion the 12.25 x 3.75 is really too much for the motor, but there's folks that love them so on the right plane it may be great.

Tim,

Thanks for the reply.

About that APC 12.25 x 3.75. I actually thought the same thing.

I don't know if guys are modifing the tips or not? You could lose a bit there. I'm also not sure if it would make any difference?

My guess is to play around with the prop and RPM's till you get your lap time.

I have to have a spinner cut. At 70.00 and change, I need to make the right choice.

Thanks again for the reply

Charles

Edited for SP.

Jim Svitko · « **Reply #3 on:** October 19, 2015, 01:40:37 PM »

Although many like the APC props I will not use them anymore. They are heavy and the trailing edge has to be modified as it is razor sharp. Also, the hub is so big that too much of the spinner has to be cut away to fit.

The Thunder Tiger 11 x 4.5, if you can find them, work very well. I also use the BY & O 11 x 4. Even the lowly Zinger can be made to work well enough.

Steven Kientz · « **Reply #4 on:** October 19, 2015, 02:59:47 PM »

I use Zinger 11x5s. Problem is they aren't being made anymore. Most of the guys I fly with have started using the Xoar 11x5s. I've tried the APCs and Master Airscrews. APCs are heavy. I don't think the MAs are truly 5 pitch, probably much less. I did try some 11x6s, on 60' lines was pretty fast.
Steve

Steve Helmick · « **Reply #5 on:** October 19, 2015, 08:34:03 PM »

Rumor has it that ZZProp is going to make CF copies of the TT 11 x 4.5. Unfortunately, like all CF props, you'll need a pitch gauge and learn how to pitch a prop to make it actually work. I'd bet that some of the Eliminator CF props would work, but there's that pitch gauge thing plus a learning curve to make them work. Somebody try some and report back!

I don't care how heavy APC props are. They work, as does the TT. However, Balsabutcher says the 11x5.5 RSM prop works well on the .46LA, and I tend to take his word for it. But remember that it always depends on the plane, the fuel you use/can get, the altitude you're flying at, and how strong your engine runs, as well as how well run-in it is. Use whatever you like.

Steve

Tim Wescott · « **Reply #6 on:** October 19, 2015, 08:35:59 PM »

Quote from: Avaiojet on October 19, 2015, 01:06:04 PM

I have to have a spinner cut. At 70.00 and change, I need to make the right choice.

The lowly Hanger 9 spinner has an ABS or similar plastic nose cone and can be rough-cut with a hobby knife and then smoothed with sandpaper wound around a stick. Then when you get your prop figured out you can get a spinner cut.

Quote from: Jim Svitko on October 19, 2015, 01:40:37 PM

The Thunder Tiger 11 x 4.5, if you can find them, work very well. I also use the BY & O 11 x 4. Even the lowly Zinger can be made to work well enough.

I was just told by a hobby shop that they've been discontinued. If that rumor proves true we need to find an alternate source.

Balsa Butcher · « **Reply #7 on:** October 19, 2015, 11:24:58 PM »

Thanks for the vote of confidence Steve. I don't remember the post but that sounds like the setup I used on a Byron Barker modded LA-46 which runs a more reliable/lower rpm 4x2 break than the stock engines. With a stock engine I'm inclined to go with the APC 11.5 x 4 but hasn't all this been covered in the "List your LA-46 setup" thread? The bottom line here is there are a lot of options and one has to experiment to find one that works for you.

Bill Johnson · « **Reply #8 on:** October 20, 2015, 12:04:45 AM »

On my vector 40, the APC 11.5 X 4 worked much better then the various Top Flight, Zinger and other APC props I tried. The 12.25 X 3.75 worked OK but most planes don't seem to have long enough landing gear. The first one I tried got "modified" to 11.75 on take-off

As far as spinners, Sig spinners fit with no modification. Various other plastic spinners are easily modified with a Dremel tool and the sanding drum. After 1 or 2, you pretty much know what to do to get it right the first time with both sides symmetrical enough to not make a difference.

On this issue of sharp mold lines on non-wood props, I was taught back in the late 60s to always sand those sharp edges off. When I started back up flying this year, I just naturally did the same thing. It's not that big of a deal, and you're not taking enough off the prop to make enough of an aerodynamic difference for anyone below the expert level to notice. Do it before balancing.

I hand prop all my engines and haven't been bitten but once, and that was making a needle adjustment. It's all in technique, just like hand propping a Piper Cub, Citabria or any other engine.

Mark Scarborough · « **Reply #9 on:** October 20, 2015, 09:24:44 AM »

APC 12.25 x 3.75

Mark Scarborough · « **Reply #10 on:** October 20, 2015, 09:25:33 AM »

APC 12.25 x 3.75
make the gear longer if needed,, it solves a couple quirks the 46 has,,

it works,,
its not to much prop
its repeatable,,,

Matt Colan · « **Reply #11 on:** October 20, 2015, 09:40:20 AM »

Best prop(s) I used on the LA 46 was a majic 12.25-4.25 and/or a 12.1-4.5 two blade carbon prop. The engine makes plenty of power to swing them with authority. I never tried the APC props that work well with the engine.

Steve Helmick · « **Reply #12 on:** October 21, 2015, 05:20:22 PM »

I would at least try the 12-4 APC. Mark, have you & Patrick tried it?

I ran a full 12-5 APC on my Humongus for one flight, and it seemed like it was "a bit much", but showed promise. Not enough speed for an OTS, but maybe for a Profile or Classic? I cut one (12-5 APC) to 11.5", intending to try it. But it found a home on my G.51, where it worked quite well. I carved the tips to as close to stock-ish as I could get them. Not impossible.

Steve

Mark Scarborough · « **Reply #13 on:** October 22, 2015, 08:15:56 AM »

Quote from: Steve Helmick on October 21, 2015, 05:20:22 PM

I would at least try the 12-4 APC. Mark, have you & Patrick tried it?

I ran a full 12-5 APC on my Humongus for one flight, and it seemed like it was "a bit much", but showed promise. Not enough speed for an OTS, but maybe for a Profile or Classic? I cut one (12-5 APC) to 11.5", intending to try it. But it found a home on my G.51, where it worked quite well. I carved the tips to as close to stock-ish as I could get them. Not impossible. Steve

yES i HAVE sTEVE,, i TRIED THE 11X4,, 11.5X4.. 12X4..12X5.. and a myriad of stock and modified wood props,, I had ONE wood prop that came close to the 12.25x3.75.. it was one I had on my Oriental ( with the wing monted gear),, it pulled like a truck .
the thing the 12.25 did that none others did was to make the needle much more docile , with the other props the LA would be hyper sensitive, if you missed lean a touch it would run for 10 minutes,, a touch rich and it would only make 4.5 minutes,, the 12.25 gave a much happier range of needle settings. note that by a touch I mean a couple hundred rpm range..
I even tried your thundertiger grey plastic thing,, did not likeit at all

Lyle Spiegel · « **Reply #14 on:** October 22, 2015, 11:46:05 AM »

On my LA 46 (setup by Byron) only using grey CYCLONE 11 x 5.5 with 10-22 fuel and either Glo Devil idle bar or Thunderbolt idle bar plug. Perfect run every time in my Vector40 , Thunderbird. My Cardinal Evolution will also have that power pack.

Motorman · « **Reply #15 on:** October 22, 2015, 01:55:15 PM »

Quote from: Steve Helmick on October 19, 2015, 08:34:03 PM

Rumor has it that ZZProp is going to make CF copies of the TT 11 x 4.5. Unfortunately, like all CF props, you'll need a pitch gauge and learn how to pitch a prop to make it actually work. I'd bet that some of the Eliminator CF props would work, but there's that pitch gauge thing plus a learning curve to make them work. Somebody try some and report back!

Why would you need a pitch gauge for a CF prop and not a plastic prop?

MM

Chris Belcher · « **Reply #16 on:** October 23, 2015, 09:14:06 AM »

I run a REV UP 11 1/2 x 5 in a true 4-2 break because of a mod I learned about years ago.....IF, and again IF you feel comfortable doing this here is what I did. Pull the liner and measure the total height of the transfer ports with a caliper. Now, with a flat needle file, file away 25 thousandths off of the TOP or 'roof' of the ports, both of them, and they have to be the same height and even all the way accross each port. The angle of the roof is 90 degrees so just keep that angle as you file. This is NOT rocket science like some would have us believe. I am not an engineer or machinist and I did this in thirty minutes. Be sure to smooth the edges, I use a cotton ball pulled through and over the edges, little tags will snag the cotton ball. Interestingly my edges did not snag at all but the machine cut stock edges did, so I smoothed those to. Put it back together after cleaning the bejesus out of everything and here is what I got....an LA46 that four strokes STRONGLY and breaks at the top of maneuvers, lots with a big venturi and less with a smaller, mine is the stock 280. Oh and add 2 head shims and run 10/22 half castor and half synthetic. Before this mod I was using 4" props and letting it run in a strong 2, and that is a great way to run these motors, but I missed the old 4-2 break from yesteryear...
Derek Picard did an article years ago about this and I had an old motor lying around and decided to try it. Now this is my favorite LA46 and I have 4 total. Your mileage may vary but I was very happy with this simple mod. Much milder and easier to set on the gournd and the power at a deep four stroke is truly amazing. At first I had the tank height off where it would not break at all on outsides but it still had plenty o line tension. It just seemed to "tame" the motor a bit and that is exactly what I wanted...more power a tthe right RPM spo icould run higher piched props. DO THIS AT YOUR OWN RISK...I used an old,but still great motor.

Gerald Arana · « **Reply #17 on:** October 23, 2015, 09:43:53 AM »

Quote from: Chris Belcher on October 23, 2015, 09:14:06 AM

I run a REV UP 11 1/2 x 5 in a true 4-2 break because of a mod I learned about years ago.....IF, and again IF you feel comfortable doing this here is what I did. Pull the liner and measure the total height of the transfer ports with a caliper. Now, with a flat needle file, file away 25 thousandths off of the TOP or 'roof' of the ports, both of them, and they have to be the same height and even all the way accross each port. The angle of the roof is 90 degrees so just keep that angle as you file. This is NOT rocket science like some would have us believe. I am not an engineer or machinist and I did this in thirty minutes. Be sure to smooth the edges, I use a cotton ball pulled through and over the edges, little tags will snag the cotton ball. Interestingly my edges did not snag at all but the machine cut stock edges did, so I smoothed those to. Put it back together after cleaning the bejesus out of everything and here is what I got....an LA46 that four strokes STRONGLY and breaks at the top of maneuvers, lots with a big venturi and less with a smaller, mine is the stock 280. Oh and add 2 head shims and run 10/22 half castor and half synthetic. Before this mod I was using 4" props and letting it run in a strong 2, and that is a great way to run these motors, but I missed the old 4-2 break from yesteryear...
Derek Picard did an article years ago about this and I had an old motor lying around and decided to try it. Now this is my favorite LA46 and I have 4 total. Your mileage may vary but I was very happy with this simple mod. Much milder and easier to set on the gournd and the power at a deep four stroke is truly amazing. At first I had the tank height off where it would not break at all on outsides but it still had plenty o line tension. It just seemed to "tame" the motor a bit and that is exactly what I wanted...more power a tthe right RPM spo icould run higher piched props. DO THIS AT YOUR OWN RISK...I used an old,but still great motor.

Chris, While you may have the skill to "Free hand" this kind of operation, I would NEVER do this to a perfectly good engine and I certainly can't/wouldn't recommend it to any one else!

I'm glad it worked out for you..............

Jerry

Andrew Tinsley · « **Reply #18 on:** October 23, 2015, 01:40:58 PM »

Hi Jerry,
I too read the article by Derek Picard a good many years ago. I thought it was rubbish, why spoil the LA46 wet two stroke run? A couple of years ago I reread the article and did the port mods. You can either angle the ports or modify the piston crown from what I remember. Results were every bit as good as Chis says.
Now there are those who preach not touching engines, well it isn't for them, but I am a fairly competent engineer and the mods are trifling to do and well worth the small effort involved. If you need to be given advice on how to do these mods, then it is NOT for you, but for anyone with a few basic skills do not be afraid to have a go. OS 46LA pistons and liners are cheap!

Andrew.

Chris Belcher · « **Reply #19 on:** October 23, 2015, 07:40:56 PM »

I thought I might get some flack on this but it's ok. I said "IF" twice at the beginning of my post. My experience with the LA46 stock was not the glorious runs I read about on SH. SEVERAL posts in the LA46 set up post say that the 12.25 x 3.75 is THE prop that the LA likes. Ground clearance, having to gut spinners and the shear weight of a huge APC prop that size was not acceptable to me. Complaints about ground rpms greatly effecting lap times and flight duration, choking the venturi down and other "issues". I said the wet 2 was a great way to run and I did so for hundreds of flights but had issues with sagging lean if you set it just a little to lean on the ground. Prop choice would make huge difference in launch rpms etc. I am NOT dissing the la46 as it has a well deserved rep but after i did the mod I was truly amazed at how powerful of a 4 stroke run I got...yeah....I'm gonna say it....reminded me of a supertigre 46 but way more consistent as I remember STs being a bit finicky at times. The LA is NOT as strong as the old ST but not that far behind. Andrew is right, if you're not comfortable doing it, don't...but boy am I glad I did!!

Steve Helmick · « **Reply #20 on:** October 23, 2015, 09:42:28 PM »

Quote from: Mark Scarborough on October 22, 2015, 08:15:56 AM

yES i HAVE sTEVE,, i TRIED THE 11X4,, 11.5X4.. 12X4..12X5.. and a myriad of stock and modified wood props,, I had ONE wood prop that came close to the 12.25x3.75.. it was one I had on my Oriental ( with the wing monted gear),, it pulled like a truck .
the thing the 12.25 did that none others did was to make the needle much more docile , with the other props the LA would be hyper sensitive, if you missed lean a touch it would run for 10 minutes,, a touch rich and it would only make 4.5 minutes,, the 12.25 gave a much happier range of needle settings. note that by a touch I mean a couple hundred rpm range..
I even tried your thundertiger grey plastic thing,, did not likeit at all

I've never used the TT 11 x 4.5 on my .46LA. I'd sure be willing to try it, since Tim and Tom like it. I don't really know why they like it, except maybe that it's consistent, doesn't take much work to balance, and it's cheap? Or was, when you could get them. The Skylark doesn't have clearance for more than 11.5" diameter, and I'd be happier with 11". Two 11" 3-blade Bollys didn't do a thing for it. I may revisit those props with the pitch gauge. I do have an idea about fixing the lack of overhead line tension, but it's not props or leadout position.

Steve