Absolutely, positively must mods for Cardinal ARF?

So here I am, having started several planes and done an outstanding job of getting them to various levels of completion, still not having actually gotten back to my hands on the handle and the plane flying.

So I bought a Brodak ARF Cardinal.

Got the video from Windy.

The inevitable compulsion is there for me to do something 'custom' to make this my plane, not just some cookie-cutter.

But, then, that misses the point of this kit. I keep getting backed up in the building (largely finishing process--no spray area) of the models, adding custom touches, or planning them and the kit gets 'stuck".

I've got a Tom Lay ST.46 G21 ready to go in the nose and now it occurs to me:

Why not just build the ##### thing EXACTLY THE WAY THE INSTRUCTIONS SAY?

There has been discussion of pinned hinges vs. CA hinges, Stab Size, bushing the leadouts on the bellcrank, etc. The latter is a good example, some saying you never dare trust the factory set-up, others claiming it's good for a thousand flights, that you will hit the ground before you saw through the bellcrank.

Etc.

So, given I really want to just build the airplane as it is described in the kit instructions--minimum excursions into "modville"--what is the forum members (with experience on the Cardinal ARF) consensus on what you absolutely MUST do to turn the contents of the box into a flyable airplane that you can depend upon?

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And a follow-up, separate question:

The instructions show trimming off the Ultracote and lining up the fuselage with the wing and then soaking the joint in THIN CA! I love CA for building wings and what not, but have heard that Nitro in the fuel will soften it.

What is the thoughts on using CA for the wing/fuse joint on the Cardinal ARF? Would it not be better to use epoxy? Or does the thin CA wicking into the wood make a better joint? Should I put a thin layer of clear finishing resin over the joint? Or is the CA joint safe for operations?

Thanks in advance.

I've used thin CA to put all of my wing/fuselage joints together and have not had a single joint problem. As long as you seal up the joints with good covering and/or paint, how can the fuel get to the joint? I also do a good job of sealing the engine compartment with thin CA so it soaks into the balsa and plywood long before any paint or clear dope is put on. Have fun. Larry

Cy,

Good questions. Succumbed to the silliness myself once, the result being what we call "The World's Most Labor Intensive Almost-Ready-to-Fly Flite Streak."

If a person needs, wants or demands a model built to his own personal standards, an ARF or ARC will surely disappoint. If one simply wants to fly with a minimum of shop time, the list of options must be very seriously truncated.

Yes, CA is soluble in nitromethane. So are a great many things we use to build our models, this including Ambroid and all paints, less only true epoxies.

I'm betting that in order to loose a tight-fitting wing-to-fuselage joint that has been glued with thin CA, one would have to soak the whole model in 98% nitromethane, not merely fuel with only 10% of the stuff, certainly not what comes out the exhaust, for days and days. Don't worry about it.

Have a Cardinal ARF but haven't put it together yet.. Probably the only thing I will change are the hinges.. Just don't care for CA hinges.

Guys - CyA is fine for building the ARF. The prototype was built with it, then splattered on asphalt, then re-built with CyA and it's holding up quite well. I'n not sure of the exact number but it's over 200 flights.
I agree on the hinges - I prefer the pin type although I've heard no negatives on the ones supplied. I installed mine with Titebond and pinned with 3/32 dowels.
I do have a question about the motor mounts - in particular, the brass threaded inserts. I installed them when I first built the plane. After many flights, one pulled out, the other three are fine. I cannot remember how many times the engine(s) have been off and on but it's many.
As this is my first experience with the inserts, I need some info - anyone out there use them long term? What is the best procedure for installation? I drilled for a snug fit, then ran the insert in to cut the threads. Then, I backed it out, coated the insert and hole with slow cure epoxy (the only epoxy on the plane), then I threaded it back in. Is this an exceptable method?
If we get too many complaints, I may switch to blind nuts for the next run.
Comments and suggestions, please!!
Bob Z.
If you're in need of some basic trim info, check on an earlier post, something about ARF pushrods.

>I do have a question about the motor mounts - in particular,
>the brass threaded inserts. I installed them when I first
>built the plane. After many flights, one pulled out, the
>other three are fine.

Uh-oh. The threaded insert "pulled out?" How could it possibly do that? The thing has to migrate through, what?, 1/4" of solid maple--or whatever material is used for motor mount sticks--and a layer or two of plywood before it could possibly come out, even if I do have to make a couple assumptions here.

I cannot remember how many times the
>engine(s) have been off and on but it's many.
>As this is my first experience with the inserts, I need some
>info - anyone out there use them long term? What is the best
>procedure for installation? I drilled for a snug fit, then
>ran the insert in to cut the threads. Then, I backed it out,
>coated the insert and hole with slow cure epoxy (the only
>epoxy on the plane), then I threaded it back in. Is this an
>exceptable method?

Depends greatly upon which side of the fuselage you are working from as to whether or not you will get exceptable (sic) results.

I say this knowing of which I speak. I once did a whack-job adaptation of my test stand, this to allow quick-and-dirty run-in of Saito 72. Threaded inserts installed from *upper* side of maple bearers. Huge mistake. That banging son-of-a-gun, once it loosened one insert the rest followed within mere moments.

I see where I goofed up installing the inserts. Since the fusleage was already constructed (fat nose doubler), I threaded them in from the outboard side. If I had done so from inboard, the epoxy would have been pushed in front of the insert, forming a barrier to prevent further movement.
Good info - THANKS!!

Thin CA tends toward the brittle side. You may get stress cracks over time - especially if there are plywood joiners that extend over the fuse-wing joint. Many of us are not perfect builders, and some gaps usually result.

I agree that if you get enough nitro to worry about loosening the joint, it will probably be the least of your concerns.

One thing I would do after you decide on the adhesive is to lay in a thin bead/fillet of clear RTV. This seems to help seal the area between the plastic covering of the wing and the plastic covering of the fuse.

Cy,

Build it and fly it.

I do not like the CA hinges (too stiff), so those I changed. I also drilled for a specific engine (Saito .40) and installed my usual threaded inserts instead of trying that Universal clamp.

Finally, I cut open the center section, took a look at the control system, and decided it would be okay as is. I did construct a carbon push rod from the flaps to the elevator with ball joints, but that is all I did.

Mine is an ARC and it took less than two days to change it to an RC (Ready to Cover). I really think you will like the way it flies.

Enjoy,

So the consensus is to come up with some pin hinges in place of the CA hinges, lay a thin fillet of silicone or other clear seal on the joints, and install a carbon fiber pushrod (which I wanted to do anyway) and then just go fly the ##### thing, right?

Sounds great.

I will have to get some hinges. There was a discussion on one of the threads here a while back about how to prepare pin hinges.

Past that, I am dedicated to making the world's most stock Cardinal ARF and going and doing some flying.

Can barely wait to get behind the legendary SuperTigre .46, which I never had a chance to do the first time around. Biggest I ever had was a green box Nobler and a Fox .35.

I think that this thread answers the question about what the point to ARF's is in an earlier thread.

The point is to resist most attempts to make them 'better' or 'custom' and just get them in the air and fly them.

God knows, I love the construction process and feel that building one's own airframe from sawing down the balsa tree is the most satisfying way to go.

But for a practical matter, I don't seem to have the time in a row to finish all of the details like I did when I was spending every waking moment not in High School building and getting ready to fly.

Will post progress here as I go.

Thanks, guys.

I took the time to put in dubro hinges, now I want to fix up the rest of it.

I'm going to use CA to get the wing lined up then fill in with some epoxy. Can't afford a mid air de-mate at my field.

I'm also very uncomfortable with the lead-out connection at the bellcrank. Would it kill them to make that a little better? A 1/4" aluminum tube with 2 dyke marks is not something any experianced modeler would do on purpose IMHO.

I'm replacing the flap control horn because there's only a small sliver of nylon around the push rod if you use the top hole.

Has anyone noticed that the engine is bolted down onto soft plywood? How long will that last before it gets squishy?

Have to beef up the tail skid with heavier wire and some wood screws if I'm going to use a stooge. A flyaway would also be very bad at my field.

Ok, Just build the plane but, I want it to be very safe and last awhile.

I think you are on the right track with those ideas. The objective for these ARC/ARF birds is to get them into the air ASAP. I'll fly this ARC until I splash it, then put another one together and keep learning.

I also love to construct these things and try to spend an hour or so in the basement every evening after work. It's the therapy I need to recover from job stress.

Save your "Good" building time for the beautiful full body stunt ship of your dreams.

I also decided to build mine with a minumum of mods. The only thing that truly made me uncomfortable was the split coupler on the elevator pushrod. I just couldn't bring myself to solder it so I hauled out the oxy/mapp torch and braised it. Overkill maybe?

I see where I goofed up installing the inserts. Since the fusleage was already constructed (fat nose doubler), I threaded them in from the outboard side. If I had done so from inboard, the epoxy would have been pushed in front of the insert, forming a barrier to prevent further movement.
Good info - THANKS!!
Bob Z.

Well, you're getting closer to a proper installation...

Remembering that I have yet to actually see the ARF/ARC in question, my inclination would be to drill fastener-sized holes completely through doublers, motor mount sticks, and whatever a fat doubler is. (Assumed to be block of balsa, used to fair fuselage into spinner, correct?)

From left side of fuselage, drill holes to size required of brass threaded inserts. These ought extend well into motor mount sticks while leaving as much wood as possible between insert and right side of said sticks.

Epoxy inserts in place, being sure to also pull them tight against bottom of holes from right side of fuselage.

The result is a secure installation. Epoxy glue *and* bottom of counter-bored holes will prevent inserts from just popping out sometime down the road.

Yes, on an ARF this means filling holes in left side of fuselage, patching with matching covering. Tough. No other way to do the job properly, in my opinion. Especially as I see the distinct possibility of a banger motor loosening one insert at beginning of flight, ripping the other three out within the next few minutes.

Actually watched this process take place with aforementioned Saito 72 on my whack-job test stand. And while it was a 72, the whole engine-removal process did not take longer than 40 seconds or so. A word to the wise...