Author Topic: ARF Nobler (Read 6706 times)

Leester · « **on:** April 30, 2006, 09:50:16 AM »

OK I know this has been covered a million times but I can't find it here on the "Hangar" I have a ARF Nobler I've had sitting in the box for 1 1/2 yrs. I'm going to start on it soon and want to get it right the first time. So what are the modifications that NEED to be made and the modifications that would be considered options.
I'm planning on either a Magnum 36 or 40.
I would like to change the bell crank and lead outs, but how do I do that without tearing the whole wing apart?
Thanks

RC Storick · « **Reply #1 on:** April 30, 2006, 09:52:53 AM »

Cut the wire close to the bell crank. Tape new wires on the old ones and pull through.

I have seen a dozen Nobler ARF's with bad motor mounts. If I were to build one I would change those too along with the landing gear.

Harleyman · « **Reply #2 on:** April 30, 2006, 10:52:45 AM »

Order an ARF Nobler drop in replacement control system from Tom Morris.
I was seriously considering just flying mine box stock, but there is no way those wimpy plastic clevises would hold up.

Andrew Hathaway · « **Reply #3 on:** April 30, 2006, 12:32:01 PM »

The last two I got both had metal clevises.
Taping the leadout wires doesn't work well, neither does heat shrink tubing. There isn't enough clearance between the leadout tubes and the wires after they're doubled up.

Cut the wires at the bellcrank end just before the crimps, overlap the new leadouts and add a drop of slow CA, a shot of kicker will seal the deal. If there is any serious excess of glue they won't slide through the leadout guides.

On my first one that I built virtually out of the box I replaced the entire control system with a 3" Sig bellcrank, Pylon c-d leadouts, dubro 4-40 rods, and used balllinks.
The stock control horns seem ok, but they're pretty short. Longer arms would make it easier to fly.

The way the motor mounts are keyed into the plywood doublers, it would be pretty difficult for them to pull out since there is a lot of area that is glued.

Aside from the control horns, the only other part of the kit hardware package that I used were the hinges. Everything else is cheap metric commie garbage.

john e. holliday · « **Reply #4 on:** April 30, 2006, 12:36:47 PM »

This is great. Now I have quite a few flights on the ARF Nobler I now find out I was supposed to replace control system. All I did was replace leadouts as I did not like the crimping. DOC Holliday

Leester · « **Reply #5 on:** April 30, 2006, 01:46:33 PM »

Andrew: Using CA on the lead outs is the way to go. I had to scrape all excess glue off and it was still tough to get them through. But I did. Thanks

Tom Dugan · « **Reply #6 on:** April 30, 2006, 02:20:04 PM »

Lee, How did you get to the bellcrank? I have an ARF Cardinal and need to do the same. I was tempted to remove all the monocote from the wing but rational thought tells me to only cut a square out big enough to get at the bellcrank.

Thomas

Leester · « **Reply #7 on:** April 30, 2006, 02:59:06 PM »

Thomas: The Nobler has a cut out area above the bell crank, and a small opening on the bottom side to get to the bolt. Both are covered by the fusalage when done.

Bob Reeves · « **Reply #8 on:** April 30, 2006, 04:41:50 PM »

If you don't mind solid leadouts you can just cut the old ones out and solids will drop right in from the wing tip. I used the stock bellcrank with solids and mine has been flying for two years in heavy wind. I did replace the clevises with Sullivan gold.

At one time I posted pictures on SSW of the bellcrank and how I did it but am sure they are long gone.

Zuriel Armstrong · « **Reply #9 on:** May 01, 2006, 04:34:11 PM »

Cut the leadouts at the belcrank. CA some thread to the leadout and pull through. CA the other end to the new leadout cable and pull it through. It fits!!!

Leester · « **Reply #10 on:** May 01, 2006, 06:11:46 PM »

Robert mentioned the landing gear being replaced. With what type and how?

Andrew Hathaway · « **Reply #11 on:** May 02, 2006, 09:10:47 AM »

The provided gear is narrower then the kit GB Nobler gear. Unless you want the wider spacing I wouldn't say its necessary. The landing gear block is pretty durable, and its keyed into the doublers. When I was demolishing the the front end of the second ARF Nobler I just grabbed the block with a visegrip and expected it to rip out. It broke in half. The remaining chunk took plywood and fuselage side with it.
The fields I have to fly off of are usually pretty rough, the gear on the Tutor II is already loose, but the Noblarf gear is just fine.

By far I'd say the biggest problem with the ARF Nobler is the hardware package. As long as all of the contents are replaced with Dubro stuff it should be fine. Great Planes hardware isn't quite as bad as the ARF stuff, but close. Life is too short to spend time fighting with soft bolts that strip out, stamped steel t-nuts that deform when they're tightened, and clevises that pull apart.

Ironbomb · « **Reply #12 on:** May 02, 2006, 12:29:23 PM »

I suppose everyone else knows that the fuel tank compt should be coated in epoxy, right? Well, I thought mine was coated from the manufacturer. The wood was, the hot glue was not. The joints of the entire fues front dissolved at a very inopportune time on my Nobler arf. At least it easy to clean for repair during its "dis-assembly"

So if you were going to coat the tank area with epoxy, good, if you didnt plan on it, then plan on it. I am still torked at Top Flight over that one.

happy building

Greg

Leester · « **Reply #13 on:** May 02, 2006, 01:45:11 PM »

Sorry Greg: but my dirrections say to fuel proof the tank area.

Ironbomb · « **Reply #14 on:** May 03, 2006, 09:07:53 AM »

Quote from: Leester on May 02, 2006, 01:45:11 PM

Sorry Greg: but my dirrections say to fuel proof the tank area.

Wow, I never read that!

I sure will go back thru my instructions and see if I need more reading lessons. How old is your plane? A new revision may correct a problem, cause Top Flight people never mentioned that either. But, I probably missed it.

No Top Flight products were harmed in the writing of this reply.

Greg

Leester · « **Reply #15 on:** May 03, 2006, 09:12:29 AM »

Greg: I bought mine over 1 1/2yrs ago. Page 12 under "mount the fuel tank" I will agree it is almost unmanly to read dirrections.

Ironbomb · « **Reply #16 on:** May 03, 2006, 10:22:31 AM »

I cant find my old instruction book to verify. Mine had the instructions for the metal tank printed, and the addendum for the plastic tank was inserted into the book as loose paper. I am pretty dang sure there was no mention to fuelproof the tank area. But,

,I have been wrong before.

Greg

brucefinley · « **Reply #17 on:** May 03, 2006, 10:45:30 AM »

Quote from: Rudderless on May 02, 2006, 11:27:50 AM

last photo

Good photo series Ty, thanks for taking the time to post. I like to see good work done even if it is on an ARF.

Bruce

Leester · « **Reply #18 on:** May 03, 2006, 11:14:56 AM »

Mine not only shows the metal tank, thats what came in it. No addendum on the plastic tank.

Leester · « **Reply #19 on:** May 03, 2006, 05:11:40 PM »

Other than the stick on wieghts how do you add needed wieght to the wing? Cut in and put a tip box? Any other ways?
I did break in the Magnum 36XLA II that I'm going to run in it. Sweeeeeet runnin engine. It has a Randy Smith venturi (have to ask Randy the size) PA NVA. Started on the 4th flip and 1 flip starts after that. Choked twice a quick prime, flip and start.

Ironbomb · « **Reply #20 on:** May 04, 2006, 08:50:51 AM »

Quote from: Leester on May 03, 2006, 11:14:56 AM

Mine not only shows the metal tank, thats what came in it. No addendum on the plastic tank.

Well, all I can say now is "DOH!!!"

Greg

Leester · « **Reply #21 on:** May 08, 2006, 11:07:16 AM »

speaking of fuel tanks, what is the problem with the metal tank that comes with it? To small? or just bad quality?

Andrew Hathaway · « **Reply #22 on:** May 08, 2006, 11:39:05 AM »

From what I understand (cause both mine were later kits with plastic clunk tanks) it was small. The later tanks have the reputation for breaking at the stopper.

Leester · « **Reply #23 on:** May 08, 2006, 08:04:54 PM »

Ty: So it actually has weight put in the tip at the factory? I'll check the balance when finished before I put a tip box in. I used a ball link at the bell crank and Gold clevisis with the retaining clip on the others.

Bob Reeves · « **Reply #24 on:** May 09, 2006, 07:27:21 AM »

Ty, with all due respect the 4-40 Sullivan gold clevis is perfectly OK for a 35 sized airplane, Even Tom Morris sells (sold) them. Just be sure to use a jam nut to prevent the threads wearing from vibration and use the little clip on the pin.

My ARF Nobler has two in it, I fly it when the wind is too high to risk my Skylark or Legacy. The control loads on my Nobler in a 25 MPH wind are a pretty good stress test.

Use only the Sullivan 4-40 Gold, use a jam nut, do not use on anything over the size of a Nobler and you will be fine.

catdaddy · « **Reply #25 on:** May 09, 2006, 10:40:43 AM »

Quote from: Rudderless on May 08, 2006, 11:39:32 PM

I have never seen or even heard of one lasting long.

Well now you have

I have one that is still okay after 4 years and over 200 flights. Just put a jam nut on it and like Bob says don't use it on anything bigger than a .35 Nobler.

Leester · « **Reply #26 on:** May 09, 2006, 01:36:25 PM »

Well I used the 4-40 Gold clevis,jam nut and the silicone retainer. I'll keep my fingers crossed, but I'm not changing it now it's all assembled. They don't give you much room to hook up anything else.

Bob Reeves · « **Reply #27 on:** May 09, 2006, 01:42:47 PM »

My Nobler is also a 40..

Tell us the details, was it a Sullivan Gold? Jam nut and clip? How did it fail?

I have seen many clevis failures, the one that comes with the Nobler ARF is junk and guaranteed to fail, same with most any 2-56 clevis except maybe on a 1/2A. Have never seen a Sullivan 4-40 fail. would like to know the details.

Bob Reeves · « **Reply #28 on:** May 11, 2006, 02:13:22 AM »

No contest just want to get the facts straight. Fully understand your position, loosing an airplane isn't fun no matter how it happens. Problem is you are making a blanket statement based on the failure of a clevis that is known to fail and not one that is considered safe to use.

Sometimes you simply do not have room for a ball link and still need the convience of an adjustable clevis.

Leester · « **Reply #29 on:** May 11, 2006, 05:11:38 PM »

Well I got her finished. Don't look bad if I say so myself. With the Magnum 36XLS and one of Randy Smiths tongue mufflers it weights 38 3/4 oz's. Only needed 1/4 oz in the tail to balance. I just have to wait for the weather to cooperate and some Saphire Blue Lustrekote for some cowling touch up and it's ready to fly. Gotta wrap the lead outs also. Sorry no pics but you know what a Nobler looks like. Thanks to everyone for the input, it really helped.

Steve Holt · « **Reply #30 on:** May 12, 2006, 11:52:46 AM »

I know that there are many people who insist on "no clevises, ever, no way, on any application" but there are places that they seem the only reasonable solution. I have been using the DuBro black nylon clevises for some time and have never had a problem. These are reinforced nylon with a removable pin locked in place with a slide lock. The threads are very tight on 4-40 threads, much like a nylon lock nut.

Has anyone had a bad experience with these?
Steve

Bob Reeves · « **Reply #31 on:** May 12, 2006, 02:27:53 PM »

Steve,

I bought a couple but have never used them. They look to be well built and if I ever find a situtation that looks like it might be the answer I wouldn't hesitate to stick one in.

Was going to use one on the plywood control horn of the Ringmaster I am currently building but the opening isn't quite wide enough. Decided to use a UHP clevis that fits great. Talk about overkill, using an eight dollar machined aluminum clevis on a Ringmaster

bob branch · « **Reply #32 on:** May 13, 2006, 09:34:52 PM »

I'd like to ask what is it about control line that results in clevis failures? I don't get it. We use them in RC extensively and do not see them fail. I mean just about never. And they are not limited to trainers but are used on 3D aircraft which have huge loads, Pattern planes which are traveling 120 mph and faster, and scale aerobatic planes that are bashed around through horrendous maneuvers with large throws at upwards to 115 mph. Not to mention absolutely every sport plane out there. I have been flying RC for only three years, but belong to 2 clubs and have never ever seen a single plane go down due to a failure. Indeed every plane I see crashed still has them attached. The gears in the servos are often stripped, the pushrods bent all to hell, and most of the plane disintegrated, but the clevis is always attached to the horn and the control surface. So what is it that is going on in stunt?

I have to also submit, that I see all kinds used, from ultra cheap all plastic ones to every type of metal one and heavy duty ones with slide out clevis' with cotter pins. I cannot believe that any stunter traveling 50 to 70 mph with control surfaces no bigger than many modern rc designs puts on more load. Yes ball links are used by some, but very few and only mostly on competition planes. Still, people fly the same kind of planes as the competition guys without ball joints and no failure mode.

bob

Bill Little · « **Reply #33 on:** May 13, 2006, 09:40:41 PM »

Quote from: bob branch on May 13, 2006, 09:34:52 PM

I'd like to ask what is it about control line that results in clevis failures? I don't get it. We use them in RC extensively and do not see them fail. I mean just about never. And they are not limited to trainers but are used on 3D aircraft which have huge loads, Pattern planes which are traveling 120 mph and faster, and scale aerobatic planes that are bashed around through horrendous maneuvers with large throws at upwards to 115 mph. Not to mention absolutely every sport plane out there. I have been flying RC for only three years, but belong to 2 clubs and have never ever seen a single plane go down due to a failure. Indeed every plane I see crashed still has them attached. The gears in the servos are often stripped, the pushrods bent all to hell, and most of the plane disintegrated, but the clevis is always attached to the horn and the control surface. So what is it that is going on in stunt?

I have to also submit, that I see all kinds used, from ultra cheap all plastic ones to every type of metal one and heavy duty ones with slide out clevis' with cotter pins. I cannot believe that any stunter traveling 50 to 70 mph with control surfaces no bigger than many modern rc designs puts on more load. Yes ball links are used by some, but very few and only mostly on competition planes. Still, people fly the same kind of planes as the competition guys without ball joints and no failure mode.

bob

Good question,Bob! One for which I do not have a good answer.

One point that has turned off the use of the ARF clevises is that they aren't even good enough to be called "cheap", at least not the ones that came in a coulpe ARFs (C/L) that I have seen. They wouldn't tighten on the threads of the pushrod (they came "Pre-stripped'!

)

An one of them had th epin just fall out. I am sure there are good clevices out there, but a ball link is so much smoother.

Alan Hahn · « **Reply #34 on:** May 13, 2006, 10:04:31 PM »

One point that is different between CL and RC is that quite often, the controls in CL are not accessible for the occasional look-see like they are for RC. (although who looks!)

Also some will state that the control forces we exert on a CL model for the square maneuvers can be quite high, enough to, over time, beat up even the good clevis.

This has become a religious issue, like the slide-on line clamps or crimping control lines. However there is truth on both sides. I built a Arf Nobler when they first came out, and except for replacing the leadouts and the tank, my Nobler was stock. At the time I wrote a review on SSW, and it was later picked up in Stunt News. In any case, I used the stock clevises and rods. However I put in some of the blue locktite (242, the non-permanent type) on the screw threads, and the system held. In fact when I finally decided to replace the clevis with a ball link the following year, it was quite tough to unnscrew the clevis from the rod. On the other hand I personally witnessed Bill Calkins put in his Arf Nobler at Sig (was it really 2 years ago?) on its second flight. I think the rod pulled out of the clevis on the downward leg of the outside square.

So I am guessing, prudence may be the best! Remember it takes only one failure to eliminate the plane.

bob branch · « **Reply #35 on:** May 13, 2006, 10:14:50 PM »

Bill

One of the things I have seen is thread mismatching. Many arf's are now coming with mostly if not all metric components. I have often seen the parts listed as non-metric in the plans, only to find out they are metric. I have seen some clevis that are non metric put in kits that have metric pushrods. The fit is very sloppy or will not go at all depending on the direction of the mismatch. I don't like to carry two sets of wrenches everywhere so I change out everything to non metric. Yes, I change out every piece of hardware in every single arf (and kit cause its happening there too) to non metric aftermarket components. I think we tend to get cheap where we should not. But I've watched all these things working in planes of all sorts.

One possible explanation is a difference in the number of flights a competition stunt flier may put a plane thru in a year vs an rc pilot. CL stunt fliers from my past experience tend to build a plane or two each year and fly them alone. RC fliers have a stable of airplanes of different types and bring 2 or 3 to the field each day and fly them all. Thus fewer flights per year. But these planes are flown for 5, 10, even some over 20 years and with the same gear. The corrosion of the parts is even noteworthy on many "favorite" planes I have seen. These planes have seen hundreds of flights.

As to loads of a square corner, I do not think they are anywhere near a 70 mph snap roll that most all rc pilots put their sport planes with the cheapest links thru. If you watch even a .60 size scale aerobatic plane do a 90 mph snap or a similar size pattern plane do it at 115mph, there is just no way a stunter can generate those loads. These maneuvers are so severe most pilots don't even fly them with their thumbs, they set up a switch to do all the control inputs simultaneously (full up, full aileron, full rudder for a snap roll). The airframe loads are frightful. Really amazing how strong model airplanes are, rc or cl.

Bob

Bob Reeves · « **Reply #36 on:** May 14, 2006, 01:24:44 AM »

Think this may have something to do with it.... Even the fastest servos cannot move as fast as you can move your wrist. Fast movement = greater load.

Alan Hahn · « **Reply #37 on:** May 15, 2006, 03:38:41 PM »

Bob,
I don't think that is correct. After all, the biggest load you can put on the plane is just the Netzband limit, which if my memory hasn't failed me from another post, is roughly 4 x the weight of the model on the single line. I am assuming here that the bellcrank isn't bottoming out on a stop and you are actually pulling the plane in towards you. So on a 40 oz plane, this would be ~160 oz, or 10 pounds of force on the bellcrank. Now the force on the rod is this 10 pounds x the mechanical advantage, which I am guessing is a factor of ~2 -- just the centerline of the bellcrank to the leadout hole divided by the distance to the rod hole. I just googled "bellcrank" and came up with Dan Winships site and it looks like this ratio is about 2. So in the case of a 40 oz ship you could be exerting ~20 lbs on the control rod threads.

Now how this compares to a servo--I don't know. The max force you can exert here is when the servo stalls out. Whether that is before max travel is reached or not, I have no clue.

Bob Reeves · « **Reply #38 on:** May 15, 2006, 06:01:43 PM »

Not a mechanical engineer can't explain it in techno geek but it's pretty obvious to me that moving a control surface fast exerts more force on linkage than the same movement would at a slower rate. Not sure the Netzband limit has anything to do with the first stages of control movement..

bob branch · « **Reply #39 on:** May 27, 2006, 09:07:54 PM »

I'm not sure I can agree with the idea that a stunter has anywhere near that much load on a control surface Bob. How many stunters have you ever heard of having the horizontal stabs fold up in a corner? This is an issue with .60 to .90 size aerobatic rc planes to the point that most of us now add 2X56 threaded rod struts from the fuse below to the hoizontal stab and from the rudder on top to it even when using hard balsa. Stuff you would never put in a stunter even for motor mounts. Anything over a .90 and they even come in the kits, though many .90 size now include some form of tailplane reinforcement. These loads are coming at speeds way in access of stunt speeds. Speed is going to increase the aerodynamic loads which is what the control system is seeing, not what we are pulling on the handle to conteract pull. I doubt any of us can actually generate 20 pounds of force on a handle in a control move. Easy to test. Someone who has 20 pound excersize weights at home, run a line from each end of the handle thru the center to a bolt to keep the line pulling thru then take up the slack and make a few square corner moves with your wrist and report the wieght response... or the doctor bill. Consider it for the good of the sport and let us know. (Thank God I don't have any of those weights. )

bob

Alan Hahn · « **Reply #40 on:** June 11, 2006, 09:17:13 AM »

Bob R.
Ordinarily you would be right that since F=ma (force=mass*acceleration), that a rapid change in motion (acceleration) would require a larger force.
But (a major but!), in the case of our control surfaces, it isn't just the rotation of the elevator/flaps that requires a force, but also the air pressure coming from the relative wind hiting the control surface. This force is a function of airspeed and the angle between the relative wind and the control suface. So assuming we are dominated by the aerodynamic force and not the simple inertial force or rotating the elevator/flap, the speed of application doesn't really matter. However it is true that a rapid input could make a have the control surface make a large angle before the plane itself starts to rotate, and this would be a large force.

You still can't exert more force than the Netzband limit---again assuming the bellcrank isn't bottoming out on a stop in the wing). And I am not clear how much force the RC snap role puts on the clevis either--those are pretty large deflections as well as large control surfaces. I don't think most of us know, so that's why I say that it isn't obvious that we are stressing the clevis more than RC'ers.

Anyway, my 2 cents (maybe 4 cents now).

hoythawkins · « **Reply #41 on:** January 01, 2007, 09:58:07 PM »

Anyone interested in modifying the ARF Nobler to be a "take apart" check out the 50 photos with edited descriptions/comments I have added. They are in the Photo-Album in the Album Section titled "ARF Nobler Take Apart." Some fine engineering by Ed Prohaska.

Hawk

Author Topic: ARF Nobler (Read 6706 times)

Alan Hahn

Alan Hahn

Alan Hahn