Author Topic: LA 25 in a ARF NOBLER (Read 21574 times)

Al Ferraro · « **on:** December 07, 2016, 11:12:39 AM »

I'm going to try a LA 25 in the ARF Nobler (got the Tower deal) and wanted to know if anyone has done this successfully? After using the Gardner piston and liner in my LA .25 powered combat plane will great results, I thought why not try it in the Nobler? I already mounted the engine by replacing the mounts with 8" long 3/8 by 1/2 maple because the stock mounts were to wide and short. I would like to know prop, tank size, fuel, etc.
Thanks Al

Fredvon4 · « **Reply #1 on:** December 07, 2016, 12:06:00 PM »

Al I would like a Nobler just for nostalgia reasons but my reading of all these threads is the plane needs a pretty strong motor... Love my La 25s on 30 oz planes but think a OS 30~32~35~40 would be a better fit for the rather porky ARF Nobler... NO experience just what I read here

If I ever do get a Nobler I think I will use my LA 40 for it

Brett Buck · « **Reply #2 on:** December 07, 2016, 10:06:23 PM »

Quote from: Al Ferraro on December 07, 2016, 11:12:39 AM

I'm going to try a LA 25 in the ARF Nobler (got the Tower deal) and wanted to know if anyone has done this successfully? After using the Gardner piston and liner in my LA .25 powered combat plane will great results, I thought why not try it in the Nobler? I already mounted the engine by replacing the mounts with 8" long 3/8 by 1/2 maple because the stock mounts were to wide and short. I would like to know prop, tank size, fuel, etc.
Thanks Al

If stock, I would expect that to work pretty well - better than the original when GMA was flying it.

Brett

Al Ferraro · « **Reply #3 on:** December 08, 2016, 08:30:38 AM »

Quote from: Brett Buck on December 07, 2016, 10:06:23 PM

If stock, I would expect that to work pretty well - better than the original when GMA was flying it.

Brett

The engine will be stock except I will be using the Gardner piston & liner that is timed at the stock spec. I have the stock muffler and a much lighter Mac header to try.
What would you recommend as a base line setup?
Thanks Al

Tim Wescott · « **Reply #4 on:** December 08, 2016, 11:46:12 AM »

Quote from: Al Ferraro on December 08, 2016, 08:30:38 AM

The engine will be stock except I will be using the Gardner piston & liner that is timed at the stock spec. I have the stock muffler and a much lighter Mac header to try.
What would you recommend as a base line setup?
Thanks Al

Stock engine, stock muffler (should be the E2030), stock "small" venturi, stock needle valve, APC 9x4 prop, 10% nitro. Launch at around 11000 or 12000 -- experiment with that. If it doesn't have enough power, try more nitro. If you get desperate, try a bigger venturi, but the bigger the venturi the less of a "break" you'll get (and even on the correct-for-25LA "wet 2" run you still get a break).

I have no personal experience with it, but there was, apparently, a running production change which means that the older 25LAs are wimpy, and the newer ones are nice and powerful. I don't know how to tell the difference without trying them out, but hopefully the Gardner P&L means that it's a "strong" one.

Brett Buck · « **Reply #5 on:** December 08, 2016, 06:42:21 PM »

Quote from: Al Ferraro on December 08, 2016, 08:30:38 AM

The engine will be stock except I will be using the Gardner piston & liner that is timed at the stock spec. I have the stock muffler and a much lighter Mac header to try.
What would you recommend as a base line setup?
Thanks Al

Dead stock in all respects, including the muffler, spraybar, etc. Start with an APC 9-4 and be sure to have a selection of 9-4, 10-3, 10-5 and 10-5 props. With the 10-5 you might end up needing 15% nitro or an air filter. As always, adjust the pitch and diameter to get the right level flight speed at a medium 2-stroke, and then evaluate the performance in the maneuvers.

The airplane is mostly OK as is, with the controls replaced of course. Carefully check the alignment of the parts and correct any misalignment in the basic structure. Also, inspect and rebuild the front end as needed. *If it was me*, I would be strongly tempted to lop off the nose and scarf on a new one, I despise the stock arrangement and parts. The stock system will stay together if the glue joints are done correctly (and many are not). Carefully inspect the leading edge, and if it is sharp, peel back the covering and round it off as much as possible, then recover. Cut a rudder loose from the fin, and make provisions to make it adjustable, same with the leadouts and tip weight.

If you were really ambitious, you would probably get a better-flying airplane if you also built an enlarged tail - just scale it up about 25% in area. Also, carve the flap down about 1/2" at the root and 1/4" at the tip. Even more ambitious, build an entire new fuselage with the enlarged tail, conventional engine mount, and increase the tail moment by an inch to ~15 1/2". All that will get you very close to my scaled-down Infinity project (which has been kicking around for about 15 years with very little action).

Brett

Skip Chernoff · « **Reply #6 on:** December 11, 2016, 09:02:58 PM »

Al I don't have any experience with the LA 25 so I can't say how good that set up can be. However, it would seem to me that you would have to rev the @#$% out of them to get any power for the vertical and overhead stuff. As you know I flew two ARF Noblers this past season,and both were .40 powered. One had an HP 40 the other an OS FSR 40. One plane was 43 oz the other 44oz. Both flew almost identically. The thing that I liked was the "drive" I would get on the "up" portion and overhead portion of the stunts(especially on windy days).
Who knows, maybe the LA25 set up will work ok for you,just wanted to mention my experience with these ARF Noblers....PhillySkip

Brett Buck · « **Reply #7 on:** December 11, 2016, 11:50:27 PM »

Quote from: Skip Chernoff on December 11, 2016, 09:02:58 PM

Al I don't have any experience with the LA 25 so I can't say how good that set up can be. However, it would seem to me that you would have to rev the @#$% out of them to get any power for the vertical and overhead stuff.

You will launch around 13,000 rpm or so. Thats not revving the "@#$%" out of them, it's barely into a 2-stroke with a 9-4 APC, presuming you have a "new" version 25LA.

Chugging around at low revs hasn't been a mainstream competitive approach *for the last 30 years*.

Brett

Dan McEntee · « **Reply #8 on:** December 12, 2016, 09:05:37 PM »

Quote from: Brett Buck on December 11, 2016, 11:50:27 PM

You will launch around 13,000 rpm or so. Thats not revving the "@#$%" out of them, it's barely into a 2-stroke with a 9-4 APC, presuming you have a "new" version 25LA.

Chugging around at low revs hasn't been a mainstream competitive approach *for the last 30 years*.

Brett

Is there any way of identifying the "new" LA.25? Other than it may be the natural finished units that are not blue? Anywhere I can read up on it? I have several of these and think a few are the natural aluminum versions. I also have a ARF Nobler that I can adapt the mounts on and want to try this when spring comes back around. I have flown the LA and FP.25 engines quite a bit in a SIG Primary Force and found them to be just enough power for that airplane and it weighed 43 or 45 ounces at the time, but is a bit smaller and cleaner than the Nobler, in my opinion. I would give the FP. just a slight edge on power, but it ran very similar to the LA and I used the prescribed E2030 muffler. I remember trying the 9-4 APC for one flight and it just wasn't happening for me enough to do a pattern. An APC 10-4 at anywhere from 10,000 to 11,000 RPM did the trick. Neither engine would pull a 10-5. I am MUCH happier with the OS.32 on my P-Force. But I would be willing to try an experiment with the proper LA.25 and a ARF Nobler. If someone has any video of one flying in that configuration, I would be interested in seeing it.
Type at you later,
Dan McEntee

Dane Martin · « **Reply #9 on:** February 01, 2017, 03:20:28 PM »

Quote from: Al Ferraro on December 07, 2016, 11:12:39 AM

I'm going to try a LA 25 in the ARF Nobler (got the Tower deal) and wanted to know if anyone has done this successfully? After using the Gardner piston and liner in my LA .25 powered combat plane will great results, I thought why not try it in the Nobler? I already mounted the engine by replacing the mounts with 8" long 3/8 by 1/2 maple because the stock mounts were to wide and short. I would like to know prop, tank size, fuel, etc.
Thanks Al

My friend dennis flys his noblearf with an OS 25 LA and I fly mine with an OS 40 LA. At first, I was slinging it around at 3.6 sec laps. I dropped down to the 25 la venturi to slow it down. I'd say the os 40 la is nice, but not a necessity. I can't tell much of a difference between flying his and mine. Maybe his is slightly lighter. They are actually pretty light as they come out of the box.

Al Ferraro · « **Reply #10 on:** February 08, 2017, 08:56:56 PM »

Quote from: Dane Martin on February 01, 2017, 03:20:28 PM

My friend dennis flys his noblearf with an OS 25 LA

What prop, fuel, and venturi size is he using.
Tanks Al

Dane Martin · « **Reply #11 on:** February 16, 2017, 06:52:05 AM »

Quote from: Al Ferraro on February 08, 2017, 08:56:56 PM

What prop, fuel, and venturi size is he using.
Tanks Al

Prop was a 10x4, fuel was 10/11/11 or 12.5/11/11
Venturi was .250 ID. Just the stock small OS venturi.
He may have switched to a 9x4 or 9x5 prop.

Ken Burdick · « **Reply #12 on:** February 16, 2017, 10:07:04 AM »

the LA.25 is a very confounding engine. It has lots of power but just seems to be otherwise.

Al Ferraro · « **Reply #13 on:** March 05, 2020, 08:09:18 PM »

Well it's just over 3 years and my LA.25 Nobler finally took to the air. I haven't zeroed in on the best prop and line length combo yet, but the LA .25 Nobler is showing some promise. I was able to do the pattern on a breezy day. I started with a Bolly 10.5 x5 prop which was a little to much load for the engine. The next prop I used was a APC 10x5 that gave me 4.8 second lap times when I ran the engine in full song. I had no problems with line tension over head but I'm looking for a little more power in the square 8s. Overall I'm really happy with this combo, and the engine answers the needle well. My setup is .280 Venturi, .156 spray bar, Macs header pipe full length, Gardner piston and liner with one head shim, Power Master GMA 10/22 fuel, 58’ 015 lines, running in a solid two stroke. The finished weight is 41 ounces. The engine only has 10 runs on it and once I hit the right prop, line length combo it's going to be a fun plane to fly. I'm getting 8 minutes on a 4-1/2 oz tank on a 48 degree day.
Al

Dan McEntee · « **Reply #14 on:** March 05, 2020, 08:25:03 PM »

On the mini-pipe, try an APC 10-4. You get the low pitch effect of handling whip up that way and your lap times will be a bit slower.. And also try the APC 9-4 and 9-5's also, and if they aren't acceptable, at least you tried them. When I am trying out props, I try everything in my box, just so I know for sure of one brand or size works.
Type at you later,
Dan McEntee

Dennis Nunes · « **Reply #15 on:** March 05, 2020, 09:09:46 PM »

Quote from: Al Ferraro on March 05, 2020, 08:09:18 PM

Well it's just over 3 years and my LA.25 Nobler finally took to the air. I haven't zeroed in on the best prop and line length combo yet, but the LA .25 Nobler is showing some promise. I was able to do the pattern on a breezy day. I started with a Bolly 10.5 x5 prop which was a little to much load for the engine. The next prop I used was a APC 10x5 that gave me 4.8 second lap times when I ran the engine in full song. I had no problems with line tension over head but I'm looking for a little more power in the square 8s. Overall I'm really happy with this combo, and the engine answers the needle well. My setup is .280 Venturi, .156 spray bar, Macs header pipe full length, Gardner piston and liner with one head shim, Power Master GMA 10/22 fuel, 58’ 015 lines, running in a solid two stroke. The finished weight is 41 ounces. The engine only has 10 runs on it and once I hit the right prop, line length combo it's going to be a fun plane to fly. I'm getting 8 minutes on a 4-1/2 oz tank on a 48 degree day.
Al

Hi Al,

From my experience with the OS 25LA I've found it to be a very powerful engine. My Circulas 25 profile has a 48" wingspan, 425 sq. in. and weights 37 oz. I fly on 60'x.012 lines. On windy days I use a APC 9x4 prop and on calm days I run a APC 10x3.

I started out running with a stock engine, muffler and remote needle valve. The plane was a bit nose-heavy with the stock muffler so I changed to a tongue muffler using muffler pressure. As a result of the tongue muffler I gained an additional 750 rpm which made the plane fly too fast. To correct this I reduced the venturi down to a.240 diameter (I'm using remote needle valve). I believe the stock venturi has a .260 diameter.

I use a full 3 oz of Power Master GMA 10/22. To set the needle, I will bring the engine up to a strong 2 stroke and then back off the needle as needed until I get a slight break of the 2 stroke and let her go. Usually around ~12,300 to 12,400 rpm.

Dennis

Terrence Durrill · « **Reply #16 on:** March 09, 2020, 11:38:55 AM »

Quote from: Al Ferraro on December 07, 2016, 11:12:39 AM

I'm going to try a LA 25 in the ARF Nobler (got the Tower deal) and wanted to know if anyone has done this successfully? After using the Gardner piston and liner in my LA .25 powered combat plane will great results, I thought why not try it in the Nobler? I already mounted the engine by replacing the mounts with 8" long 3/8 by 1/2 maple because the stock mounts were to wide and short. I would like to know prop, tank size, fuel, etc.
Thanks Al

You can't go wrong with a Fox .35 stunt or an O.S. Max .35S in a Nobler............very reliability and loads of fun.

Al Ferraro · « **Reply #17 on:** April 29, 2020, 10:28:58 PM »

I have been flying the LA.25 Nobler and have found a pretty solid combination.
Prop: APC 10x4. I tried the 9" props but the line tension was not there. The APC 10x3 revved the engine to much to get near 5.0 lap times, to much gear.
Exhaust: Mac's header with a .270 restrictor in the end. I have a 4-1/2 oz tank and was getting 8 minutes of run time with the Mac's header and a .390 restrictor. I then switched to the stock OS muffler and the engine ran for 11 minutes with a slight power loss. The stock muffler would be a keeper except the extra weight made the plane not corner as good. I made a .270 restrictor for the Mac's header and my run time went to 10 minutes and regained the lost power and corners.
Plug: Sig P2003
Fuel: Power Master GMA 10 nitro 22% oil
Venturi: OS .280 with a .156 Super Tigre needle valve assembly.
Piston & liner: Brian Gardner ABC using a stock OS head and a .008 gasket.
Lines: 58' .015
Weight: 42 oz
The engine run is a solid two stroke that burps rich in some of the corners, and is real steady throughout the pattern. The lap times are 5.1 to 4.9, the plane handles the wind well and is a real joy to fly. I am going to replace the tank to a 3-1/2 oz to save some weight and fuel load, plus keep exploring different props.
Al

Shorts,David · « **Reply #18 on:** April 30, 2020, 10:40:49 AM »

Quote from: Brett Buck on December 08, 2016, 06:42:21 PM

The airplane is mostly OK as is, with the controls replaced of course. Carefully check the alignment of the parts and correct any misalignment in the basic structure. Also, inspect and rebuild the front end as needed. *If it was me*, I would be strongly tempted to lop off the nose and scarf on a new one, I despise the stock arrangement and parts. The stock system will stay together if the glue joints are done correctly (and many are not). Carefully inspect the leading edge, and if it is sharp, peel back the covering and round it off as much as possible, then recover. Cut a rudder loose from the fin, and make provisions to make it adjustable, same with the leadouts and tip weight.

If you were really ambitious, you would probably get a better-flying airplane if you also built an enlarged tail - just scale it up about 25% in area. Also, carve the flap down about 1/2" at the root and 1/4" at the tip. Even more ambitious, build an entire new fuselage with the enlarged tail, conventional engine mount, and increase the tail moment by an inch to ~15 1/2". All that will get you very close to my scaled-down Infinity project (which has been kicking around for about 15 years with very little action).

Brett

I'm marking this since I got a Brodak Nobler kit for my birthday.

Al Ferraro · « **Reply #19 on:** May 17, 2020, 09:40:02 PM »

Here’s a video of the LA 25 powered Nobler. It was quite breezy and in the top of the hour glass and again in the clover I got hit with a crosswind that would have given any model a problem. I was able to hang on and complete the maneuvers out of shape. Run time was about 7 minutes using 3-1/2 oz of fuel.
Al

jfv · « **Reply #20 on:** May 19, 2020, 06:18:16 PM »

Working pretty well!

C.T. Schaefer · « **Reply #21 on:** May 20, 2020, 05:56:27 AM »

Extra point awarded for saving the cloverleaf

Al Ferraro · « **Reply #22 on:** June 23, 2020, 09:22:25 PM »

" I HIT THE SWEET SPOT"
Yes after trying a bunch of props from 9x4 to 10.5x5 and even a 10x5 three blade, I hit the magic prop, and it did not cost $50. The LA .25 powered ARF Nobler fly's amazing, 5.2 lap times, steady as a rock and corners hard with great line tension up top. I have to say this is probable the best engine combo for the Nobler ever. 7 minute run time on 3-1/2 oz of fuel. I have a 4-1/2 oz tank in the Nobler and when I pull out 1 oz of fuel to fly I can really feel the difference in the way the plane corners. I will be removing the larger tank to install a new 3-1/2 tank as there is no need for a larger engine.
Al

Brent Williams · « **Reply #23 on:** June 23, 2020, 11:24:57 PM »

Quote from: Al Ferraro on June 23, 2020, 09:22:25 PM

" I HIT THE SWEET SPOT"
Yes after trying a bunch of props from 9x4 to 10.5x5 and even a 10x5 three blade, I hit the magic prop, and it did not cost $50.

So is your magic prop the APC 10x4 that you mentioned earlier?

Brett Buck · « **Reply #24 on:** June 23, 2020, 11:27:57 PM »

Quote from: Al Ferraro on June 23, 2020, 09:22:25 PM

" I HIT THE SWEET SPOT"
Yes after trying a bunch of props from 9x4 to 10.5x5 and even a 10x5 three blade, I hit the magic prop, and it did not cost $50. The LA .25 powered ARF Nobler fly's amazing, 5.2 lap times, steady as a rock and corners hard with great line tension up top. I have to say this is probable the best engine combo for the Nobler ever. 7 minute run time on 3-1/2 oz of fuel. I have a 4-1/2 oz tank in the Nobler and when I pull out 1 oz of fuel to fly I can really feel the difference in the way the plane corners. I will be removing the larger tank to install a new 3-1/2 tank as there is no need for a larger engine.
Al

Which prop might that be?

Interesting that you can tell the difference in the fuel load. That's always what strikes me when I fly classic airplanes, they respond much faster at the end of the flight than the beginning. The Nobler and derivatives are particularly bad about it, the super-giant flaps and small tail are already pretty swoopy, put 4 ounces of fuel in, and it's much worse.

Brett

Al Ferraro · « **Reply #25 on:** June 24, 2020, 07:00:26 PM »

Which prop might that be?

Brett
[/quote]
The magic prop is a APC 9.625 x 3.75N, It out performed every other prop in cornering, stability, line tension and engine rpm. The second best prop was the APC 10 x 4. The APC 9 x 4 did not pull the Nobler well and was the worst prop, I really had to rev the @#$% out of engine to get to 5 sec lap times, and the plane felt like it wanted fall out of the sky. I thought the Bolly Clubman 10.5 x 5 would give me the most solid flight with out any hunting, but the 9.625 x 3.75N is the clear winner by far. The Nobler is easy to fly and I'm really enjoying It.
Al

Dan McEntee · « **Reply #26 on:** June 28, 2020, 10:32:48 PM »

The correct prop for each airplane is the one that works! How do you figure that out? By trying different props! I have probably 1000 props or more of various brands and vintages in my collection, and when asked, "Why do you have so many props?", this is why! We don't have as many off the shelf props available these days, so when I found a prop that worked well for one airplane and set up, I would try to stock up on that prop in case it be needed on another set up. APC has these stiletto shaped props is a few sizes that I have tried, and they sometimes work surprisingly well. They have a 12-4 "sport prop" that looks like this one and it works very well on the LA.46, and a 12-5 that handled the ST.51 in my Shark45 OK also. The one problem these days is the decreasing number of hobby shops and the ones that are still around do not stock much on the way of propellers, so you can't just go in and look around and see what's available. Now that I have heard of this size, I'll see if my local hobby shop can order a few for me, and if they perform to my liking on my airplane then I'll order up a few more to have on hand and maybe let some one else try if needed. There is no better feeling than finding that magic prop that really lets the engine do it's job and that you can feel the difference at the handle also. That's the reason most of us do this!
Type at you later,
Dan McEntee

Ken Culbertson · « **Reply #27 on:** June 29, 2020, 10:24:26 PM »

Quote from: Dan McEntee on June 28, 2020, 10:32:48 PM

That's the reason most of us do this!
Type at you later,
Dan McEntee

And all along I thought it was to get the cute girls...damn.

Ken

Allen Eshleman · « **Reply #28 on:** July 05, 2020, 01:17:34 PM »

I have found that the 10.5x4 1/2 works best for my LA 40 on a Banshee. I might try an 11 1/2 x 4 1/2 or a 12x3.

Brett Buck · « **Reply #29 on:** July 05, 2020, 04:59:11 PM »

Quote from: Al Ferraro on June 24, 2020, 07:00:26 PM

Which prop might that be?

Brett

The magic prop is a APC 9.625 x 3.75N, It out performed every other prop in cornering, stability, line tension and engine rpm. The second best prop was the APC 10 x 4. The APC 9 x 4 did not pull the Nobler well and was the worst prop, I really had to rev the @#$% out of engine to get to 5 sec lap times, and the plane felt like it wanted fall out of the sky. I thought the Bolly Clubman 10.5 x 5 would give me the most solid flight with out any hunting, but the 9.625 x 3.75N is the clear winner by far. The Nobler is easy to fly and I'm really enjoying It.
Al

That's interesting, because I am using the 9-4 as a starting point because it *does* cause the airplane to fly slower than a 10-4 (the flip side of having run the heck out of it to get a larger airplane to go fast enough). Two sides of the same coin.

The classic mistake with these engines is not allowing them to rev up enough, or being afraid to rev them up. Using a 9-4 instead of a 10-4 on the kinds of airplanes I was testing was inefficient enough to allow the engine to be revved up/set for more shaft power. For a much larger airplane, it makes sense that you could tolerate/require more efficient props.

Sound like you are being very logical and careful about your development, not just trying stuff at random and hoping it works, so, excellent information.

Brett

Mark Mc · « **Reply #30 on:** August 24, 2020, 08:55:35 PM »

Quote from: Al Ferraro on June 24, 2020, 07:00:26 PM

The magic prop is a APC 9.625 x 3.75N, It out performed every other prop in cornering, stability, line tension and engine rpm.
Al

After reading this post at the beginning of this month, I ordered some of these "magic" props to try on my .25 LAs. I finally got out today. Actually, first time in a year for me to get out flying. When I pulled the prop out of the sleeve, I was skeptical, as the blade width was narrower and the blade profile didn't seem optimal. But try it I did. I was happily surprised with this prop on my Skyray. More pull than the other props I'd tried before. Performed better than the APC 10x4 that was on there, and better than the 9x4 before that. I was never very happy with either the 10x4 or the 9x4. Both just seemed wrong for this particular plane/engine. Glad I ordered three of the 9.625x3.75N props. Now I just have to get good with the plane.

Thanks for the info,
Mark