Covering's

Just curious as to peoples opinions out there as to using Monocoat? I have seen it refered to various ways here and was wondering why it is not that popular? I have to agree that the painted finishes that you see in Stunt News are spectacular but not all of us have the skill or time or money to put into one of those. I know I sure don't. Monocoat keeps me from inhaling to much dope fumes and that is supposed to be a good thing but I can't remember why!?!?

Bill

Bill. Monokote, or similar plastic films are just fine. I use it for R/C gliders. There are some builders out there who can make a neat job with Monokote, but I'm not one of them. Once the film is ironed on, little dings, pimples and "whoopies" in the structure cannot be fixed. Overlaps cannot be hidden. Wrinkles are inherent, and they make me furious. Therefore, I prefer silk or SGM silkspan for covering. To each his own.

Hi Bill,

Its all a matter of personal preference. I use all kinds of coverings and finishes. My favorite for stunters happens to be silkspan and dope, but I've also used silk, Monokote and tissue. Don't worry about what people say, use what you like.

>Just curious as to peoples opinions out there as to using
>Monocoat? I have seen it refered to various ways here and
>was wondering why it is not that popular? I have to agree
>that the painted finishes that you see in Stunt News are

Bill;

For a lot of us, Monocoat is a fine covering. It goes on fast, is durable, and like you said, saves one from dealing with the fumes from a painted finish.

There are some aspects about Monocoat that folks don't like. Here are some of them:

1. Very difficult to blend seams.
2. Sags and stretches in the sun - has to be retightened from time to time.
3. Can resonate and make a "tinny" sound.
4. Once wrinkled, very hard to reduce the wrinkle without removing and trashing the entire panel.

I am sure others have their pet peeves as well.

There is one other aspect that must be accounted for if applying Monocoat or any film on a built up structure. Monocoat, though strong, will stretch a little when a tension load is applied. This is different from doped silk and silkspan, which tends not to stretch. A good number of designs rely on the covering for strength. If you use Monocoat, that is reduced or lost, and you get a lot of flexing and or twisting - especially with wings. Now, wings on airliners flex, and that is ok. For stunt ships, it isn't, and will accelerate failure. I-Beam wings are the most notorious for this. Cover one with Monocoat instead of silkspan and the wings look like they are almost flapping. Other design that will flex a good bit are the Sig Twister and Banshee. Lots of folks fly them stock with Monocoat, but they will flex more with a film covering than with a silkspan or silk covering, and that means the wing will eventually fail.

Does this mean ships like the Twister and Banshee can't be covered with 'coat? No. My latest stock Twister wing has some diagonal bracing between the spars and web fillers between the ribs at the TE. Wing is considerably more rigid than before. Just for grins I am going to cover this one with Monocoat and see how it holds up. Total time for the mods was about 1 hour - far less than I would spend with a conventional dope finish.

The moral of all this is that if you want to Monocoat, just look at the design of the ship and see if there are components that rely on the covering for torsional rigidity and strength. If there are, then some judicious reinforcement will be in order.

I have seen some absolutely drop dead pretty finishing jobs done with Monocoat. Let the truth be known, most people can probably finish better with Monocoat than they can with dope. While some people may look down on Monocoat, if it helps you get a ship in the air and maintain your health, go for it.

Bob FYI:

My TwistMaster is Monokote, stock Twister wing, only mods being the addition of 1/2 ribs, no additional bracing. It is now 4 seasons old with many hundreds of flights. The last several flights were with Video equipment aboard which turned it into a 47 ounce Twister. If anything was going to give I would think it would have happened during the video flights. The covering is showing it's age but still looks pretty good. Your Twister should be fine.

>turned it into a 47 ounce Twister. If anything was going to
>give I would think it would have happened during the video
>flights. The covering is showing it's age but still looks
>pretty good. Your Twister should be fine.

Bob;

Back in the mid 1980s I built two stock Twisters - well almost stock. I did change the rudder design and the canopy profile. Both were monocoated. Monocoat was a good deal for someone who was in the service and didn't have the room for a lot of finishing stuff. Both flexed a lot. One flexed more than the other, and the wing failed. When I rebuilt it, I used silkspan and clear dope, and the flexing went away.

As with everyone, mileage may vary. I didn't have any scales back then, so finished weight was an afterthought. In fact, I can't remember which one failed, e.g. whether it had a Max-S 35 or a Fox 35 in the nose. I know of other folks who have flown them with Monocoat with good success. The ship is a good design and good value for the money. The one I am building has a derivation of the Rabe BBQB bellcrank mounting and the reinforcing I mentioned. I figure it will be a near swap in weight considering the lighter weight of a Monocoat finish. BTW - it also has your simple strip half ribs.

I'm going to use polyspan on mine simply because there are no compound curves to get in the way on the tips! Like anything polyspan has advantages and disadvantages. Disadvantage: It does not provide as much torsional strength as plain old silkspan does. Advantage: It is very tough and tear resistant. Very hard to puncture due to hanger rash, dropped things ect! Also it requires a bit different technique for finishing than siklspan.

Bob:
Nothing wrong with using monocoat, a lot of the big guns have been very successful with it. I use silk span and/or carbon fiber for strength because I'm looking for that extra 5% from my models performance. I admire someone who can do a nice finish with the plastic coverings. They do save a lot of weight.

Larry Foster

Bob:
Film finishes are great at all levels of Stuntdom! The GSCB has a couple of very skilled film appliers....Al Knight and Mike Cooper. Dennis Toth (Fla) does a terrific job, too!

Advantages of film are that it goes on fairly quickly and is more than likely lighter than other finishes. Bob Kruger did a great job of explaining the disadvantages, but they are generally pretty trivial at most levels of competition.

Phil Cartier (Ferocious...before the snafu) vends a film that goes on easily, stays on, goes around corners and is paintable.....try some, it's amazing.

The guys that do top notch film covering will tell you that surface prep is the key, just as the guys that use pc or silk and dope....

See Ya

The Flite Streak and Nobler ARFs use it very successfully. I also love to use the iron-on coverings. Although I love the smell of a good old dope and silkspan finish, the koats keep me from killing the last seven brain cells that I have left.
Chris

I've built a couple Twisters. One had 1/8 sq spruce turbulator spars, 2 each top and bottom. It was monocoated and worked fine for many many flights. The other was silkspan and worked fine until the non-plasticized aerogloss started cracking.

I like tissue, silk, silkpan, and Sig Plyspan. Plyspan with plasticized dope is very tough. I've seen Plyspanned wings survive major crashes undamaged. Crashes which I think would have split Monocoat. If you want stiff, put silkspan under your monocoat on the wings.

I'd like to try the British FF trick of using a thin Mylar with tissue on top. Takes a very minor amount of dope and for FF purposes can be made lighter than tissue and dope. Wonder how silkspan over monocoat would work?

Heck I thought that was De Hill talking

Rich, is this another version of OZ cover? I have some OZ cover but have yet to use it, seriously thinking about using it on the Skylark.

LAST EDITED ON Dec-24-03 AT 01:28 PM (CDT)
 
That looks like De Hill in that picture from Peabody!

Bill

First rate finishes are possible with Monokote, you just need to sit back and plan them a little different than silk and dope. Frame preparation are just as critical as well. I think where the upturned noses start coming from is that it is a heck of a lot easier to make a model that is fuelproof and ready to fly with Monokote than it is with a doped surface. I can have an airplane ready to cover and flying tomorrow where with a doped finish takes quite a bit longer. It is also a whole lot easier to just slap on a monotone covering and go fly.

Now at my level of flying, it probably would make perfect sense to just get a covering on and go practice, but you do have to practice finishing too, it's all part of the skills.

I have a mixture of 50/50 models down stairs, monokote or doped. My favorite is a doped woven fabric that goes on like monokote, but then requires dopeing. It's sooooo tough.

Dear Rich,

Why are you using my Avatar?

cordially,

De Hill

LAST EDITED ON Dec-26-03 AT 09:53 AM (CDT)
 
You might talk to Da Dirt. Dan does some really fine finishes with Monokote. His Oriental's Monokote finish is almost indistinguishable from paint. Just ask Pat Johnston. He thought it was paint.

Dan is a real artist with Monokote.

Randy Powell

Edit: wish I could type

Bill I think you should give up on Monokote and stick to dope and tissue....Can I have your Monokote supply?

Phil, I really would like to give you the 45 rolls of monocoat in my shop but they are all colors you would like. Whats the fun in that???

Bill

Bill:
I think it's safe to say that the plastic coverings are not looked down on like they were several years back. I hope the same thing will happen with the ARF's.

Larry Foster

bkruger,

Sorry, but I have to question your statement that a MonoKoted wing is destined to fail if not "beefed up". There are many, many R/C models with plastic film-covered wings out there that are quite old and doing well.

In fact, some R/C wings are DESIGNED to use the strength of shrunk film to give rigidity; the turbulator spar wing on the Sig Four Stars and BTE Venture, to name a couple. Both were designed by Bruce Tharpe, who is as well known and respected in the R/C side of the house as George Aldrich is here.

So, unless C/L stunt wings are subjected to much more stress than an R/C wing- and I have difficulty imagining that, especially with the "3D" craze going on right now- I simply do not see where you're coming from on this.

RC wings are generally WAY overbuilt, so they are fairly stiff without any covering. A Twister wing is much less rigid, like the 4 Star. BTW, the 4 star has a notoriously flexible, flimsy wing. Their favorite trick in a slightly faster dive is to start to flutter and blow up.

Anyway, a Twister will fly quite well with film covering. A little extra stiffening in the form of some half ribs, a few spar webs, and maybe some diagonal stiffeners that were mentioned would be easy, cheap insurance.

LAST EDITED ON Dec-26-03 AT 08:31 AM (CDT)
 
>bkruger,
>
>Sorry, but I have to question your statement that a
>MonoKoted wing is destined to fail if not "beefed up". There
>are many, many R/C models with plastic film-covered wings
>out there that are quite old and doing well.
....
>
>So, unless C/L stunt wings are subjected to much more
>stress than an R/C wing- and I have difficulty imagining
>that, especially with the "3D" craze going on right now- I
>simply do not see where you're coming from on this.

That is the great thing about this forum - we can agree to disagree.

My point was and is that Monocoat does not impart the torsional rigidity resistance to tension loads that a doped silkspan or silk. Note - this has nothing to do with its resistance to puncture - a great feature of Monocoat. But, don't take my word for it. Build two identical I-Beam or C-Tube wing ships, or even two SIG Twisters. Cover the wing of one with Monocoat, and the other with silk or silkspan and dope. See which one flexes less. The debate will be over very quickly for you. It was for me.

Does that mean I don't use Monocoat any more? Absolutely not. I personally like the stuff. I just know that by using it, I have to take into account the wing design and the covering to insure a reasonable amount of longevity.

As for stresses on RC versus CL, that is an interesting question. Considering the fact that CL flight is limited to a hemisphere and all maneuvers may be performed there, our ships could arguable be said to generate more G-Forces. But, then you are comparing apples to oranges, as there is such a variety of RC out there that a comparison is really useless.

Interestingly, years ago when dabbling with RC a friend of mine built a Goldberg Falcon 56 - a design that predates Monocoat. This ship was built during the winter of 1983-84. He decided to cover it in Monocoat. While helping him cover it, I mentioned that there was a lot of flex in the wing that he would not have had if covered with silk or silkspan. I related to him my tale of woe with an I-Beam wing some years earlier when I needed to recover it quickly and used Monocoat rather than silkspan. A few months later, on a moderately windy day, I watched the wings fold and the ship auger in. I don't believe under those conditions the failure would have happened had he used silkspan or silk, or reinforced the center and did a little diagonal cross bracing in the wing to compensate for the stretching effect of Monocoat. The original design was for silkspan or silk, not Monocoat.

So will a wing finished in Monocoat fail immediately? Probably not, nor does it necessarily mean that it fail at all. What it does mean is that if the wing design factors in the covering as part of the wing's ability to handle tension loads and torsional loads, then you need to understand that, unmodified, the wing will flex more, and with that flexing comes shorter life. And that's not opinion - that's just a fact.

But, like I said, don't take my word for it. Build two identical I-Beam or C-Tube wings, cover one with Monocat and one with silkspan or silk and dope, and find out for yourself. I think you will be somewhat surprised.

v/r - Bob

Give me Ultracote over $cote any day. It goes around wingtips easier, for one thing.

>Give me Ultracote over $cote any day. It goes around
>wingtips easier, for one thing.

It is nice stuff to work with. However, it does like to sag in the sun, something we have no shortage of here in Gawga. If I still lived up north, I would probably use Ultracoat

Lou Scovone'a Shoestring is covered with Monokote. He does fantastic work as he uses what looks like 100 pieces to get his planes looking great! One thing I like about Monokote it is easier to get those pesky warps out. Now if I can only build straighter I will try silk span.

Jay

<<...flutter and blow up...>>

Hmmm... I'm on my third 4 Star 40; built this one for the grandson, and his favorite thing is chasing buzzards with it; talk about G forces...

I have seen no less than a dozen of these models, built to varying degrees of quality. Never seen, nor heard of, any Four Star wings "blowing up". Perhaps the aileron gaps in the ones you refer to weren't sealed, etc.

Okay, bkruger, I understand your reasoning. Not sure if I buy into it, but I appreciate your well-written clarification.

BTW, I prefer UltraCote myself. You're right; U-cote, being a polyester (as opposed to plastic) film, does react to sunlight/high ambient heat more adversely than MonoKote. But U-Cote is infinitely more user-friendly, so I'm willing to pay that price. And I'm in south Louisiana, so you ain't got nuttin' on us here in the semi-tropics.

I'll retire soon, and the wife isn't far behind me. We are getting the hell out of this miserable place.

And, how is THAT for thread drift???

>Okay, bkruger, I understand your reasoning. Not sure if I
>buy into it, but I appreciate your well-written
>clarification.

Don't take my word for it. Try U-coat on a stock Twister and compare it to one covered with silkspan or silk.

>U-Cote is infinitely more user-friendly, so I'm willing to
>pay that price. And I'm in south Louisiana, so you ain't got
>nuttin' on us here in the semi-tropics.

I bow to you. My last trip to FT Polk reminded me just how much I hated the climate there. Heaven to some, but not me.

>And, how is THAT for thread drift???

Not real bad - yet.