OS LA .25 (And .46)

Hello all.
I just read an earlier posting on this subject.
I noticed that Mike Pratt suggested the following modifications to the OS .25 LA : (i just purchased one and have run it only on bench for a few minutes)
250 dia. venturi (from Leonard at SSW)
S. T. needle valve assembly.
Tongue Muffler. Modified RSM or SSW

Problem is that i am living in Norway, and this stuff is impossible to get hold of here
If anyone are able to get hold of this and ship it to me, please drop me a mail, so we can agree on details.
I also have a (Stock .46)
Any ideas on improvements here.
I have not run it yet (mid winter in Norway) , but from what i read it should be ok in the stock version.

I have LA 25's, 46's, and a 40. If you buy the control line LA engine , you really don't have to do anything but run it. While you can replace the remote needle valve, plastic back plate and use a different muffler, it is only a choice and not mandatory. These are really user friendly engines right out of the box, that can be refined if one wants to. Of course, if you start out with an R/C engine you probably will want to modify it for sure.

Leonard Neumann IS SSW, and also our host here. He can provide everything you need to setup your OS .25 & .46, and ships to Japan and other places, so I'm sure he would be very willing and able to send what you need. I don't think Leonard would say that himself, and I would add only that changing to the metal backplates and front needle valves is to increase reliability and reduce the chances of a bad needle setting, both intended to increase durability, steady running and enjoyment. The trade-off is a bit more cost, and putting your fingers closer to the propeller. Steve

"Leonard Neumann" <[email protected]>

I have two LA 25s and one LA 40. All have the ST needle valves, nothing else. One 25 uses the stock muffler with the baffle removed. The other has a tongue muffler. Both run great with an APC 9x4 or Grish Tornado hard plastic 9x4 on a 37 oz Primary Force. The other on a 31.4 OZ Don Stills Stuka with an apc 10x4 and tongue muffler. Both start with one spinner backspin with the thumb and first two fingers after two primes, 8-10 turnovers, three backflips and a couple spinner flips before adding the battery to the plug then usually the first flip it starts. The LA 40 does the same. I can't say enough about these motors for first time modelers and modelers who want to fly rather than tinker.

Bob Smiley
A Lancair 360 builder/pilot trying to be a modeler

Well..
First thank you all for the nice and informative answers.
I myself work with software support for a large american software company.I cannot always give such good answers to my customers.

There is however on thing i use to tell them if they ask for tweaks and tuning etc. : "If it is not broken, do not fix it".
So i guess my best plan for now will be to give both engines a proper break in, then put them on the planes and start flying. Then get back to you all with the results from that.
.....
One more Q. about the .25 LA . I have already an ARF Flite Streak ready for it to be used as a trainer, but i am planning to build another 'real' stunter for it. That will be a scaled down wing from a Trivial Pursuit with an ordinary nose section and a twin boom. Something similar to the Carousel shown here.
Question is: How much will the .25 pull , 40" wingspan, 42" 44" or...?
I intend to build as light as possible.
Norvald Olsvold

Hmmm, I had no idea Bill Netzeband is now living in Norway, nor did I have a clue that he might be tempted into naming one of his models "Carousel."

Just goes to show ya this is a very unpredictable world.

LAST EDITED ON Jan-20-04 AT 04:54 PM (CDT)
 
>Hmmm, I had no idea Bill Netzeband is now living in Norway,
>nor did I have a clue that he might be tempted into naming
>one of his models "Carousel."

Well , i have not seen Bill around either.
I was of the opinion that the picture shows
Carousel 52" by Mackay published in American Modeler
# 3/61 (1961-2)
It also has the name Carousel on the inner wing half.
I think he won the junior NATS in 1959 with it.
I may be mistaken.
Norvald Olsvold

LAST EDITED ON Jan-20-04 AT 06:53 PM (CDT)
 
>.....
>One more Q. about the .25 LA . I have already an ARF Flite
>Streak ready for it to be used as a trainer, but i am
>planning to build another 'real' stunter for it. That will
>be a scaled down wing from a Trivial Pursuit with an
>ordinary nose section and a twin boom. Something similar to
>the Carousel shown here.
>Question is: How much will the .25 pull , 40" wingspan, 42"
>44" or...?
>I intend to build as light as possible.
>Norvald Olsvold

How about 475 sq in. and 36 oz. That is what I'd aim for.

LAST EDITED ON Jan-20-04 AT 09:40 PM (CDT)
 
Giving a thorough and proper breakin to an OS .25/.46 LA is worthy of about two or three tanks of fuel, each. In the model, on the ground. Follow the instructions! There's not much to it, and it works. Yes, they will get better, but that's all you need. If it needles well and runs steady, it's ready to fly. My .46 went up on the second tank, and ran great, no regrets.

Bob's "Don Still Stuka" is just about as perfect a match for the .25 as you could ask for. I haven't seen it fly yet, but did see his (larger) Mathis "Excalibur" fly with the .25. The "Stuka" fits Crist's specs perfectly. Steve

>>.....
>>One more Q. about the .25 LA . I have already an ARF Flite
>>Streak ready for it to be used as a trainer, but i am
>>planning to build another 'real' stunter for it. That will
>>be a scaled down wing from a Trivial Pursuit with an
>>ordinary nose section and a twin boom. Something similar to
>>the Carousel shown here.
>>Question is: How much will the .25 pull , 40" wingspan, 42"
>>44" or...?
>>I intend to build as light as possible.
>>Norvald Olsvold
>
>How about 475 sq in. and 36 oz. That is what I'd aim for.

For the 25FP, no problem. I have seen very good - and I mean very good *by any standards* - 25FP airplanes around this size.

I am less convinced that the 25LA is up to such a task - maybe, but then again, maybe not. I would err on the side of small until proven otherwise. A full-fuse 475 square inch flapped airplane could easily end up in the mid 40 oz range, and I think this is almost certain to be too heavy for the engine (although probably fine for the wing loading). I would go no larger than 400 squares and shoot for low 30's.

More info to chew on.

My Primary Force is just shy of 500 square inches. 50.5 inch wingspan. all wing area since only a profile body. Weighs now at 38 oz for a 10.9 oz per square foot wing loading. Flying on 62 foot .012 lines in Tuscon AZ elevation about 2,200 burning 13% nitro blend 22% oil using a 9x4 tornado grish propeller. 5 second laps. pulls like a horse with slight engine offset, no wingtip weight eliminates hinging. Get that, no tip weight. I must thank Bob Whitely for that. He said you are heavy at the tip. Hmmmm good choice of wood. Anyway with this setup you can fly a pattern and the plane flies without stalling or stumbling. It is on the high end of the weight scale and this the beginning of its second season with some battle wounds with grass and pavement.

Thoughts?. The plane flies about as well as can be expected. Yes, I would like it to be a couple oz lighter for tighter turns but the line tension is great. The motor runs free and does not load up in maneuvers. If your engine loads up; you need another prop to let it run. These motors like the revs to keep up the power.

In summary. the OS25 is a pretty solid generic motor. It should be used for a plane no larger than the Primary Force at about 36 oz. or at about 9.5 to 10.25 oz wing loading. I surmise a heavier wing loading adds stability and perhaps line tension at expense of maneuverability.

My Stuka weighs 31.4 oZ at a lighter wing loading. (Not fully tested at this time). Results so far are: it is very maneuverable, promises to be a great flyer, does not hunt, stable, makes clean sharp corners without stalling. Problem to resolve at this time is lack of line tension. WHY? probably no engine offset, shaped rudder is not effective enough to work. Ligher plane. Not enough speed or I am more comfortable with more line tension. Still to early to tell. Anyway the OSLA25 promises to be a very good motor for that plane and it is plenty of power. I remember that Don used the Fox 25 on his earlier models which is significantly less HP than the OS. Dee Rice loves his little Stuka.

Bob Smiley
A Lancair 360 builder/pilot trying to be a modeler

Bob, are you really using .012" lines on the Primary Force? NOT LEGAL per current AMA regs. Adequate, just not legal. Steve

012 solids are legal up to 40. Read your AMA rulebook!

Steve; the lines I referred to are solid .012 x 62foot. Had my first experience in moist air with those lines grabbing. Interesting flight. I can see why we do not use them in the Northwest. Down here and in California about half the guys use solids unless it is raining or the grass is wet. So I suppose it is a tossup. Perhaps serious competition in the south warrants solids say in high density altitude high temp situations where every ounce of advantage is needed to eke out that margin advantage. But my preference is to use braided wire.

LAST EDITED ON Feb-07-04 AT 01:46 PM (CDT)
 
Hi. Just one quick question.
Just received a collection of glow plugs from Mr. Leonard N.
Any of you guys know the difference (if any) between the Fox 'Miracle'
and the Fox R/C Long.
Just curious...
Norvald Olsvold

>Hi. Just one quick question.
>Just received a collection of glow plugs from Mr. Leonard N.
>Any of you guys know the difference (if any) between the Fox
>'Miracle'
>and the Fox R/C Long.
>Just curious...
>Norvald Olsvold

If you look at them carefully, you will see that the RC long has the idle bar while the Miracle plug uses a heavier element and extends a bit deeper into the head cavity. It was designed for 4-stroke work. Both of these are hot plugs and work well for our stunt purposes. Although there will be a hundred different opinions as to which plug is best and which is worst, we have pretty much found these to be interchangeable for our purposes. I would suggest you try both in your various engines and see which, if either you prefer.

Thanks...
I had a test run with the OS .25 LA and the R/C long in minus 2 C and snow today. Started on second flip and ran nicely.