Author Topic: Nobler ARF trimming questing / pulls like a mule (Read 25390 times)

Dane Martin · « **on:** February 27, 2016, 08:16:18 PM »

So i picked up a new, finished but never flown noblearf from an estate sale. I flew it today, but man oh man was it strange. It pulls unbelievably hard. I think my heavy pulse jet speed plane pulls less! Lol. All i have done was replumb the tank to my liking (standard clunk on muffler pressure). I also swapped out the engine to an already broke in os40 la. I'll list the set up i had today. I have another one of these things with the same set up, and i don't remember it pulling like this one.

Here's the set up...
OS40 LA
Zinger 11x5 prop
60' 018 lines
I didn't tach it, but the engine run was nice. I didn't time laps, but they felt reasonable. I know, that's not a good measurement, but i fly speed so it felt slow to me. Wings we're level upright and inverted.
Hanging it from the lead outs shows about 5 degrees nose down. Any ideas, or just bad set up?

Tim Wescott · « **Reply #1 on:** February 27, 2016, 09:29:18 PM »

Get a lap time! At least count "one one thousand, two one thousand" and try to figure what's close.

Did you do any overhead maneuvers? Did it pull hard? If "yes", then it's just too damned fast and you need to slow it down to five seconds or more.

Dane Martin · « **Reply #2 on:** February 27, 2016, 09:49:40 PM »

Lol, i know. Sorry. If the engine run was great, i can play with the prop sure, but would longer lines be the answer to slowing it down? If that is in fact the issue.

Dane Martin · « **Reply #3 on:** February 27, 2016, 10:25:34 PM »

Tim, i just remembered my friend Kevin recorded most of the flight. I texted him and had him time the laps.
Ok, I don't want to post the lap time because I'm dumb, but i want to post it because it's hilarious.... 3.66 sec!
I suppose timing the laps can be a very helpful tool! But honest, it felt slow to me, haha

Tim Wescott · « **Reply #4 on:** February 27, 2016, 10:31:59 PM »

Well, the dual advantages of a 3.66 second lap time are that you won't run out of line tension, and it should be easy to fit the pattern in the allotted time.

However, you may still want to slow the plane down.

I really think you want to try a 4-pitch prop on that engine. I'd go with an APC 11-4 and an APC 11.5-4. Try launching at 9500 RPM, and if the engine speeds up much in the air then ask here.

Having said that, some people manage to find a run with the 40LA that's more like a Fox 35. I've never been able to manage it, but if you really want to you could try dramatically richening the engine with the same prop and see what happens.

Mark Scarborough · « **Reply #5 on:** February 27, 2016, 10:44:57 PM »

Hey Tim, I will let you explain how important a tach, and a stopwatch are ok?

Tim Wescott · « **Reply #6 on:** February 27, 2016, 11:20:49 PM »

Dane, as for line length, I think you should first get it to five second laps and see what you think. I'm pretty sure that the ARF Nobler is usually happy on 60' lines.

Dane Martin · « **Reply #7 on:** February 27, 2016, 11:56:42 PM »

Ok, that works. Now, i think i share your view on engine runs. I don't think i like the idea of just richening it up. I have some three and four pitch props to experiment with. Thank you for the ideas!

Dane Martin · « **Reply #8 on:** February 28, 2016, 12:04:03 PM »

Quote from: Mark Scarborough on February 27, 2016, 10:44:57 PM

Hey Tim, I will let you explain how important a tach, and a stopwatch are ok?

Is this comment due to the result of a funny field experiment? Lol

Mark Scarborough · « **Reply #9 on:** February 28, 2016, 12:07:28 PM »

Not really, its more about how long we ( I ) poked at Tim to get him to tach his plane before each flight,,

Tim Wescott · « **Reply #10 on:** February 28, 2016, 01:28:26 PM »

Quote from: Dane Martin on February 27, 2016, 11:56:42 PM

Ok, that works. Now, i think i share your view on engine runs. I don't think i like the idea of just richening it up. I have some three and four pitch props to experiment with. Thank you for the ideas!

You do want to judiciously richen it, though. "Just right" for a good stunt run is "horribly rich" for RC or combat or carrier or FF or -- well, you get the idea.

Dane Martin · « **Reply #11 on:** February 28, 2016, 03:33:33 PM »

Yeah, that stunt run is an elusive creature... Ok, so i just put the 11x4 on. I'll bring the tach this time! I'll let you know in a couple hours

Tim Wescott · « **Reply #12 on:** February 28, 2016, 03:39:55 PM »

Quote from: Dane Martin on February 28, 2016, 03:33:33 PM

Yeah, that stunt run is an elusive creature... Ok, so i just put the 11x4 on. I'll bring the tach this time! I'll let you know in a couple hours

This has been covered extensively. These threads should be helpful. They're about the 46LA which is regarded as a much better engine than the 40LA -- I can't give you an opinion, because I only have one 40LA, and it came to me reworked.

http://stunthanger.com/smf/engine-set-up-tips/o-s-la-46-rc-to-cl/
http://stunthanger.com/smf/engine-set-up-tips/list-'your'-set-up-for-the-os-46la/

Dane Martin · « **Reply #13 on:** February 28, 2016, 03:51:49 PM »

I do have some NIB os46 la's but... This is just an ARF. The 40la is great for practicing. Well good enough for me. I'll save the better engines for planes i build. Actually, Pat Johnston modified the RM800+p to the RM645+p for the LVCB so we could have a spec class so to speak a around the 46la. He sent us a bunch and they are remarkable on the 46la power.
I ramble a little, but that's where my 46's are going

Tim Wescott · « **Reply #14 on:** February 28, 2016, 05:36:21 PM »

Call it a "break in mule" and bung a 46 in there!

Dane Martin · « **Reply #15 on:** February 28, 2016, 06:33:55 PM »

I like that, i might try that after today!
So i had this 40la in a Tudor2 and it was fine i guess. Haven't flown that in probably 2 years. The 40la runs great.... Above 10500 only. If i richen it up to run at 9500, it just slows down after a few seconds and dies. So either i have a cold plug, or i can't run like that with the big venturi.
So I'll maybe move that over to engine set up. But as for now, when i get the speed down i can tell it's flying better.
Slower engine speed and an 11x4 prop today. Felt better!

Tim Wescott · « **Reply #16 on:** February 28, 2016, 06:46:46 PM »

Quote from: Dane Martin on February 28, 2016, 06:33:55 PM

... or i can't run like that with the big venturi.

In one of the threads I quoted I explain how I pile on layers of thin nylon net (pantyhose, etc.) to effectively reduce the venturi size. There's basically a right size -- too big and the engine tends to run away (or die); too small and the engine doesn't pick up on the up lines, and sort of "thins out" at the tops of maneuvers. There's a happy medium you need to find.

Dane Martin · « **Reply #17 on:** February 28, 2016, 07:20:26 PM »

I read that. Joe Gilbert showed me at the round-up in 2014 also. I really like that idea. This cowl makes it a pain to deal with that, but i'll figure something out.
I am in a small way happy about the improvements made by just a prop change and lowering the rpm. my goal is to get back in practice with this thing before
flying the strega.
Thanks for the help Tim, this is nice to see the improvements instantly. Its difficult to do this alone. My "helpers" have been RC guys for the past two days! Very
cool field we have here

Chris Fretz · « **Reply #18 on:** February 28, 2016, 08:49:49 PM »

Quote from: Tim Wescott on February 27, 2016, 09:29:18 PM

Get a lap time! At least count "one one thousand, two one thousand" and try to figure what's close.

Did you do any overhead maneuvers? Did it pull hard? If "yes", then it's just too damned fast and you need to slow it down to five seconds or more.

Does the 5sec rule work for all airplanes on 60ft lines?

Brett Buck · « **Reply #19 on:** February 28, 2016, 10:13:40 PM »

Quote from: Tim Wescott on February 28, 2016, 06:46:46 PM

In one of the threads I quoted I explain how I pile on layers of thin nylon net (pantyhose, etc.) to effectively reduce the venturi size. There's basically a right size -- too big and the engine tends to run away (or die); too small and the engine doesn't pick up on the up lines, and sort of "thins out" at the tops of maneuvers. There's a happy medium you need to find.

And, importantly, the slower you run it, the less venturi you can tolerate.

Brett

Dane Martin · « **Reply #20 on:** February 28, 2016, 10:26:34 PM »

Quote from: Brett Buck on February 28, 2016, 10:13:40 PM

And, importantly, the slower you run it, the less venturi you can tolerate.

Brett

Meaning to run in a lower rpm range I'll need a smaller venturi regardless of the means to get it? The engine run now is very consistent with a nice clean shut off. So if i had a smaller venturi, am i "shifting" that good run range into a slower RPM?

Edit: I'm leaving that question because i think it could be valid. But it just dawned on me I'm running 20%. I usually only fly 4 strokes, so that's what's in my field box. Let me change fuels before continuing experimenting

Dane Martin · « **Reply #21 on:** February 29, 2016, 07:43:25 AM »

Quote from: #Liner on February 28, 2016, 08:49:49 PM

Does the 5sec rule work for all airplanes on 60ft lines?

Just cuz no one else answered this yet, I'll say no. I have ringmasters on 60' lines that are in the 4.2 - 4.6 range. I think a ringmaster flying at 3.66 sec would feel more nimble than this nobler! Lol.
Then of course there's speed planes. I do around 2 sec laps on 60' lines!

Chris Fretz · « **Reply #22 on:** February 29, 2016, 10:32:00 AM »

Quote from: Dane Martin on February 29, 2016, 07:43:25 AM

Just cuz no one else answered this yet, I'll say no. I have ringmasters on 60' lines that are in the 4.2 - 4.6 range. I think a ringmaster flying at 3.66 sec would feel more nimble than this nobler! Lol.
Then of course there's speed planes. I do around 2 sec laps on 60' lines!

I probably should of been more specific when I asked, like more for stunt. Thanks for the insite.

Tim Wescott · « **Reply #23 on:** February 29, 2016, 10:45:42 AM »

Quote from: Dane Martin on February 28, 2016, 10:26:34 PM

Meaning to run in a lower rpm range I'll need a smaller venturi regardless of the means to get it? The engine run now is very consistent with a nice clean shut off. So if i had a smaller venturi, am i "shifting" that good run range into a slower RPM?

Yes. The nylon net over the intake is just a handy way to achieve the restriction. You could machine yourself a dozen venturis ranging from too small to too big and then swap them around until you got the run you wanted. Folks have made adjustable venturis, and if it weren't for the fact that they don't work right* when you try it, you could use an RC carb and tweak the throttle opening.

Quote from: Dane Martin on February 28, 2016, 10:26:34 PM

Edit: I'm leaving that question because i think it could be valid. But it just dawned on me I'm running 20%. I usually only fly 4 strokes, so that's what's in my field box. Let me change fuels before continuing experimenting

This may have an effect, but not a big one. By all means drop down to 10% and see what happens.

* At least people SAY they don't work right -- I've got one that's working right, at least at the moment.

Dane Martin · « **Reply #24 on:** February 29, 2016, 01:10:41 PM »

10-4 Tim. I'll drop the nitro a little. But i do like the nylon net idea over turning out a boat load of venturis.... Not sure of the plural form there...

Target · « **Reply #25 on:** March 04, 2016, 08:58:04 PM »

Tim-
What about adding a head gasket or a thicker one to get a bit lower compression??
I think my buddy Don did this to my OS .40 FP, and that, and a smaller venturi, and a little port work he did, makes the FP do a perfect run for stunt. It NEVER runs away, ever. And I only have a 10" prop on it.
Dane-
I'll ask Don what size venturi you should be running and post back here for you, he's great with stunt engines.

R,
Chris

Target · « **Reply #26 on:** March 04, 2016, 10:14:00 PM »

Quote from: Chris Behm on March 04, 2016, 08:58:04 PM

Tim-
What about adding a head gasket or a thicker one to get a bit lower compression??
I think my buddy Don did this to my OS .40 FP, and that, and a smaller venture, and a little port work he did, makes the FP do a perfect run for stunt. It NEVER runs away, ever. And I only have a 10" prop on it.
Dane-
I'll ask Don what size venturi you should be running and post back here for you, he's great with stunt engines.

R,
Chris

Dane-
Don says ADD one .015" head gasket (making two for a total of .030") and use a .240"-.250" venturi, prop pitch about 4", and 5-10% nitro fuel. You should then be able to set the ground RPM to 9200-9400 without it dying, and it shouldn't run away when it's airborne....He also says that the OS.46LA has a better port timing stock from the factory for stunt flying. The same mods work on it, but better.
I'd get rid of the muffler pressure tank setup also, and go with a uni-flow. That's what our group runs, and it works perfectly, but adjusting the tank height is important for even running upright and inverted.

Dane Martin · « **Reply #27 on:** March 05, 2016, 09:35:20 PM »

Quote from: Chris Behm on March 04, 2016, 10:14:00 PM

Dane-
Don says ADD one .015" head gasket (making two for a total of .030") and use a .240"-.250" venturi, prop pitch about 4", and 5-10% nitro fuel. You should then be able to set the ground RPM to 9200-9400 without it dying, and it shouldn't run away when it's airborne....He also says that the OS.46LA has a better port timing stock from the factory for stunt flying. The same mods work on it, but better.
I'd get rid of the muffler pressure tank setup also, and go with a uni-flow. That's what our group runs, and it works perfectly, but adjusting the tank height is important for even running upright and inverted.

Thanks Chris. Just for the sake of leaving the plane the way it is, i can't find a good way to fit panty hose and o-rings without cutting away more cowl. So, instead i changed to a .250 venturi. If i can get 9500 on the ground, then i believe I'm in the money. If the venturi doesn't slow it down enough, i can try another head shim, or smaller venturi. I don't want to do anything with the tank as of now... The run is perfect. No run away, and equal up and down. The only reason I'm doing anything at all is just the airspeed. The engine actually is impressing me so far. My friend Art Leis built this plane before he passed away. He made all the good modifications, he just never flew it. It's turning out to be a nice practice ship

Edit: however, i have yet to compete the pattern with this plane so far.... 4 strokes are easier to slow down a plane.... Maybe an os30 fs??

Target · « **Reply #28 on:** March 05, 2016, 11:50:19 PM »

Alright, well, best of luck. You can add the head shim as necessary. Also try to get some low nitro fuel.
That, and a 4" pitch prop should point you in the right direction....
These things just seem much easier to me with electrics!
Have fun/kind regards,
Chris

Dane Martin · « **Reply #29 on:** March 07, 2016, 10:40:42 AM »

Lol, the electrics are really nice! I have a .250 venturi and an 11x4 prop right now. One change at a time has been isolating the problem very well here. No flying this last weekend, the winds were unreal and i picked up a little side job for the weekend. I'll update the flight report as soon as i get to fly again

Steve Helmick · « **Reply #30 on:** March 10, 2016, 01:41:21 PM »

If you're sticking with the .40LA, I'd change props, lower nitro, add a head gasket, shift the CG aft, move the LO's, and change to longer .015" lines (62' eye to eye, maybe)...all, before I went to a smaller venturi. Runaway is normally heat related...not enough total running time, low oil content, too much prop, too restrictive a muffler, etc. Read Randy's pinned posts. Note that a less restrictive muffler = bigger venturi, etc. A bigger venturi, running more fuel through the engine can make it run cooler and more stable with the same load. Burning more fuel is often better.

Pete Ferguson had a .40LA on a Brodak Profile Cardinal that didn't run well. Put on the magic 11 x 4.5 TT Cyclone prop, a head gasket (I think) and a Randy Aero CNC tube muffler (to move the CG aft), 10-22 Powermaster, with a .157" spraybar through the stock venturi, and it was quite nice. Note that early .40LA's had boost ports, but later ones do not. Which is yours?

Steve

Dane Martin · « **Reply #31 on:** March 10, 2016, 02:06:03 PM »

I have no run away problems. It's a very consistent run, every flight. I'll have to check the version Steve. I'm not sure on that.
But yes, I'm sticking with the 40la. Probably just to be difficult... Lol.

Jim Carter · « **Reply #32 on:** March 10, 2016, 02:17:59 PM »

Yo Bro Dane! Cuz! I know all these guys have great idea about changing stuff .... spendin' mo' money an' stuff .... buyin' more props .... swappin' mo' engines!! Well, I say don't change a thing!! If you really need to slow it down a bit in-flight just add something like this before you take off!! http://ts1.mm.bing.net/th?id=OIP.M3c24bf6a22a4e36516eacde8a7098b32o0&pid=15.1&rs=1&c=1&qlt=95&w=152&h=101#inline

(Ain't I helpful!!

)

Dane Martin · « **Reply #33 on:** March 10, 2016, 02:48:21 PM »

Jeez, this is a rough crowd.... Lol!
Next time i call, i need to talk to your wife.. Have her set you straight....

Steve Helmick · « **Reply #34 on:** March 12, 2016, 10:04:55 PM »

Quote from: Dane Martin on March 10, 2016, 02:06:03 PM

I have no run away problems. It's a very consistent run, every flight.

If you're getting laps at under 4.5 seconds each, I can't fathom that heat (or vibration/fuel foaming) isn't causing a "runaway" situation. Can easily be very consistent, every flight, every day. Something's wrong, and needs fixing. You wrote that the engine quits cleanly at the end of the tank. That indicates that it's lean all the way to the end, and also that there probably isn't a significant yaw problem caused by CG too forward for the LO location. Any more clues you're holding out on us?

Steve

Dane Martin · « **Reply #35 on:** March 13, 2016, 12:49:13 AM »

Lol! Probably... But I'm not good enough to remember everything after the flight!
The biggest issue was high pitch prop, and big venturi. I was swinging a 5 pitch at over 12,000. That's a lot of airspeed! Lol!

Steve Helmick · « **Reply #36 on:** March 20, 2016, 12:28:00 AM »

I forgot to add "not enough cooling air"...usually insufficient outlet, not inlet, since hot air expands. Have you got that NoblARF whipped into shape yet?

Steve

Tim Wescott · « **Reply #37 on:** March 20, 2016, 07:46:06 AM »

Quote from: Steve Helmick on March 12, 2016, 10:04:55 PM

If you're getting laps at under 4.5 seconds each, I can't fathom that heat (or vibration/fuel foaming) isn't causing a "runaway" situation.

Runaway is when you start nicely and then speed up. It sounds more like Dane was starting fast and staying that way.

Dane Martin · « **Reply #38 on:** March 20, 2016, 03:43:53 PM »

Quote from: Steve Helmick on March 20, 2016, 12:28:00 AM

Have you got that NoblARF whipped into shape yet? Steve

I'm going to say yes. I feel no more big changes are necessary. Just a little fine tuning. I'll tach it and time it later today. I ended up just sticking the .250 venturi in it. Sorry Tim, lol. Il like the restriction method with the nylon mesh, but when i go out, i usually only get two flights to test. No time for experimenting between flights to get it perfect. Just close enough for now

Tim Wescott · « **Reply #39 on:** March 20, 2016, 04:59:12 PM »

If you want to get closer later, you'll know what to do.

I'd give you hell for only flying two flights at a time, but half the time I go flying that's all I manage.

Leo Mehl · « **Reply #40 on:** March 25, 2016, 02:06:18 PM »

Go to 65 or 63 foot lines and try to get your engine to run at a for stroke and break into a two stroke as the nose of the plane goes up and back to a four stroke at level flight. The Nobler arf is a good airplane as are all Noblers but it need s to be trimmed and trimming the motor run is the most important part of the process because witout a good motor run it is hard to trim the rest of the flying trims.

john e. holliday · « **Reply #41 on:** March 26, 2016, 11:39:02 AM »

I believe that is the statement Wendy said about flying a new plane. Engine run, wings level and CG in right spot.

Skip Chernoff · « **Reply #42 on:** July 04, 2016, 08:34:19 AM »

I'm flying two ARF Noblers with .40 mills. Both planes fly on 63' x .015 lines handle centerline to plane centerline. The handles have little overhang. I'm using the stock tanks with muffler pressure. Both planes love the APC 10.5x 4.5 prop. I use 3/4 oz tip weight and both needed some tail weight,about 25grams (attached to rudder base) This helped me to get some nice square corners. I like these planes and if "assembled"with great care ,do fly well......Just my 2 cents....PhillySkip

Avaiojet · « **Reply #43 on:** July 04, 2016, 01:35:08 PM »

Quote from: Skip Chernoff on July 04, 2016, 08:34:19 AM

I'm flying two ARF Noblers with .40 mills. Both planes fly on 63' x .015 lines handle centerline to plane centerline. The handles have little overhang. I'm using the stock tanks with muffler pressure. Both planes love the APC 10.5x 4.5 prop. I use 3/4 oz tip weight and both needed some tail weight,about 25grams (attached to rudder base) This helped me to get some nice square corners. I like these planes and if "assembled"with great care ,do fly well......Just my 2 cents....PhillySkip

Skip,

You didn't mention pushrod changes as some modelers do. Any changes there?

Charles

Skip Chernoff · « **Reply #44 on:** July 04, 2016, 07:09:48 PM »

Sorry, I did forget that I used arrow shaft push rods on both planes.....PhillySkip

Avaiojet · « **Reply #45 on:** July 26, 2016, 09:23:55 AM »

"Great" Dane,

Do you think your Nobler was assembled right out of the box or do you think changes were made to it?

Charles

Dane Martin · « **Reply #46 on:** July 26, 2016, 03:39:00 PM »

Charles,
I knew the individual who assembled this plane. He's was a very good friend of mine who passed away. I do know that his building skills were amazing, and this ARF was just because he liked the nobler. Sorry, I'm rambling.
Anyway, he assembled it as per the instructions, just to see how it felt. Then, he never got to fly it.

Avaiojet · « **Reply #47 on:** July 26, 2016, 04:02:17 PM »

Quote from: Dane Martin on July 26, 2016, 03:39:00 PM

Charles,
I knew the individual who assembled this plane. He's was a very good friend of mine who passed away. I do know that his building skills were amazing, and this ARF was just because he liked the nobler. Sorry, I'm rambling.
Anyway, he assembled it as per the instructions, just to see how it felt. Then, he never got to fly it.

"Great" Dane,

Sorry about your friend, take good care of that Nobler.

I would like to just assemble my Nobler right out of the box, but I don't believe that would be wise.

Rambling is good, it makes for more interesting Posts.

Charles