iFLYrc_Vic

My Feedback: (6)

If I converted a control line plane to an RC plane, how would it fly?

My major question is about the vertical stabilizer. The vertical stabilizer on most CL planes is relatively short compared to those on a similar RC plane.
1. How would the short vertical stabilizer affect the flight characteristics even with a rudder?
2. Would the plane "skid" through turns?
3. Would the rudder be more effective?

Thanks,
Vic

BMatthews

It would depend on the design. If it's a combat model or a stunt model with little or no fin area then obviously something would need to be added. If it's got a sizeable fin area already then it might very well be just fine.

For example a Flite Streak would likely be fine with no added area to the vertical fin. Just put a hinge line at about 50% chord. A Ringmaster might be OK or it might end up doing some funky things in turns and at lower airspeeds. It would certainly be in the marginal range. There are a number of stunt models that have no fin. Just a deepened rear ridge line to the fuselage. On such as those you'd want to add some sort of rear fin.

All Day Dan

My Feedback: (5)

Vick I designed an RC Barnstormer a while ago and it flew great. The entire plane was enlarged about 10% to get everything to fit. Dan.

BMatthews

The Barnstormer being one of the CL designs that already has enough fin area without any issue.

That looks like a very nice adaptation there Dan. Does it fly as sweet as it looks?

I have to say that all this is making me think that an RC Flite Streak would be a pretty slick model to build. Profile fuselage, no landing gear and just do a nice easy underhand launch using the "canopy" as a grab handle.

sensei

A Flite Streak would make for a great R/C, I loved my C/L version back in the day. An old flying buddy of mine converted a Ringmaster to R/C around 14 years ago, it was one of the best flying profiles I ever flew. just saying...

Bob

JohnBuckner

My Feedback: (1)

I would much prefer going the other way around RC to controlline, anyway another consideration that needs to be considered on such a conversion is the offset wings on many controlline designs with a longer inboard wing than the outboard such as my magician. This would be difficult to deal with so choice of subjects is important.

Somewhere around twenty years ago Tower sold an RC version of the Nobeler with a much fatter fuselage. It apparently flew pretty well but was not a success in the market place and to my eye it lost its charm and character visually being more like just another sport RC plane.

John

All Day Dan

My Feedback: (5)

I had a great time flying the RC Barnstormer especially when all the "old" guys recognized it. I'll attach an image of the plans that appeared in the November 1989 issue of Flying Models. It should help the original poster. I eventually gave it to someone who just had to have it. Dan.

BMatthews

I tend to agree with John about how things could quickly lose their appeal when changes are made. And let's face facts. We can't take a design that is highly optimized for working in only what amounts to one dimension (pitch) and expect it to perform well in all three just by taking off the lines. Control line stunt designs have overly bloated wings and tails with little side area and a lack of fin as already mentioned in the great many cases. Yet they have a beauty all their own which becomes muddied rapidly if changes to make them suitable for RC are done. I can't imagine a fatted up Steve Wooley Aries adapted to RC. It simply would not be the same at all. On the other hand a DeBolt Champion stunter would do just fine as an RC model without any changes at all other than some extra hinge lines for the added control surfaces.

Lnewqban

Isn't wing loading purposely higher for CL designs?

BMatthews

Like most things it depends. Stunt and combat models have low wing loadings for the size by RC standards. Speed models and speed related models tend to have any where from high to hellishly high wing loading. But then so do RC models intended purely for speed.

Purposely higher? No, not really. It was just that to keep the models flying fast enough to keep them at the end of the lines that early models tended to be overpowered by RC standards back then. Hence the old "brick on a string" comparison made by RC modelers back then. But these days the situation is pretty much reversed. Where a single or two channel model of around 56 inch span used to be built light and powered by a .15 these days such a model is considered as barely adequate with a .40. So the old distinctions have pretty much faded and when comparing stunt and combat models the wing loadings and power loadings are pretty much equal.

Lnewqban

Thank you for the detailed explanation, BMatthews.

Hossfly

You can convert any model or bunch of balsa and plywood to any model airplane that you wish to do so. What is an "original design"? Just that! Whatever you want it to be. If you have a knife, pliers, screwdriver along with some glue, you can convert the materials to almost anything. Many clubs host fun-events, one being a crew has access to a bunch of broken parts and they go for who can come up with a flyable airplane. I have converted many model kits to another model. I have built many original designs in CL, RC, and Free Flight. I will try to get this forum to use several pictures to show. It doesn't work well for me. I don't know shOt about computers, but building a model is simply doing whatever you wish.

The Hurricane was built from a rubber powered kit. Excellent Scale Pylon Racer for its .25 class. The yellow mustang was a Scale racer using a nelson .40, untril it mated another nice machine around the pylon. The skeleton was started some 20 months ago as my design for a CL Stunter. I worked on it about 3 months, and it has not improved itself this past 17 months. DRATS! The Bipe was built from and restructured from a very old Japanese CL kit. Flies very well RC with ST 51, even with the warp in the wings.
You can do anything you WANT to do. You can make it do your bidding. BTW this machine was built using a CL wing and I forgot to cut off the 1/2 inch on one side. Fuse. is FOAM BOARD as well as the tail feathers. Flew well for several years with O.P.S .60. Finally sold it.

HighPlains

My Feedback: (1)

A while back (45 years ago), Orbit showed their newest small radio in a full bodied Ringmaster. The only modification was that the wing chord was reduced along with the addition of ailerons and a rudder of course. It was powered with a .15 sized engine (as a CL model it used a .35), but most of the drag is from the control lines to the airplane.

I built a CL combat model called the Guillotine into a RC model in 1972 that flew very well. Mostly had to add a couple of vertical stabilizers onto the booms, and find room for the tank and radio. It was a bit smaller than the Sig Wonder, but similar in configuration though the elevator was like most combat designs with no fixed horizontal stabilizer.

a70eliminator

I converted my u-control Stunt Master with McCoy35 engine to RC with os-fp40 carbed engine, I removed the weight from right wing added a hinged rudder and flew it on the first try. Flying U-contol makes learning RC a snap as you already know what to expect when the plane leaves the ground, at least for me it was.

sensei

+1

Bob

aspeed

I remember reading an article in a magazine from the 1960's about converting to rc. They added dihedral, and I think used a smaller motor. The balance on a control line is usually farther forward than RC as well. Radios and motors were much different then. Many motors had no throttle, so they were all built a bit underpowered. Things have changed, mostly that the prices of RC stuff is cheaper than U Control stuff now. I was eyeing a OMP Sukoi RC profile plane in my basement to make control line. Going the other way, from rc.

a70eliminator

I did no modifications to the wing or elevator just simply hinged and horned the rudder, mounted 3 servos and strapped the battery and reciever to the fuse, the elevator already had the horn, I still remember how magnificant She flew free of any wire, this back in the late 70's. And of course I had balance the CG.
Aspeed I too am thinking of going back to control line I still have that McCoy and a ringmaster with a boken tail section to fix, still have a set of cables too! I'm going to climb up into the attic and get it tonight, that will certainly get me going, want to teach someone to RC and cable would be a good start.

speedracerntrixie

My Feedback: (29)

I have always thought that converting a Sig stunt Super Chippy to R/C would be cool. Some of the modern stunt designs are just sexy as hell.

vertical grimmace

My Feedback: (1)

You can calculate tail volume, and see exactly what would be acceptable fin area for your given wing area/tail moment. This holds true for the stab/elev area as well. Generally, stab/elev area on CL planes is more than needed for RC.
I am of the opinion that with such small radio equipment available to us now, "fattening" up an older design would not be necessary. One thing to keep in mind would be to keep your aircraft light, as the fully symmetrical airfoils will not be very forgiving at slow speeds, like landing. Of course, a little washout would not hurt, if needed.

BMatthews

VG, a slight correction. The fat symmetrical airfoils typically used on stunt, sport stunt and combat models will be very gentle at slow speeds. The thickness of these airfoils delays and softens the final stall to the point where they are very easy to fly slowly and give good warning before the break.

These same characteristics show up on the old "fat winged" fun fly models popular a decade or so back.

And of course as with any model a light overall weight to give a lower wing loading value goes a long way to helping.

vertical grimmace

My Feedback: (1)

The key to those fun fly designs was light weight. I guess my point is, if you build it heavy, typical of a lot of RC aircraft, the symmetrical airfoil will give you grief. It will be a non issue if built light.
In all of my years flying CL competitively, everyone was constantly chasing light weight. Hence, the aircraft are designed accordingly. While not the sam as RC, a CL aircraft is perfectly capable of stalling. Especially when pushing the limits.

Hossfly

Yes, VG, any airplane will stall if the pilot supplies adequate load factor. Once the angle-of-attack creates adequate separation of the airflow ( that point where dynamic pressure is inadequate to prevent airflow separation) the machine gets ready to take a nap. That is one of the reasons so many modelers have a problem with landings, which in reality are a very easy maneuver. Dynamic pressure can be retained by prop. speed (airspeed), until the angle of attack is too much for the applied force. A heavy model needs to come in very low, adequate power to maintain a skimming attitude, ease back on the engine speed which will create a nose high attitude. Too much power-off will simply take away the stab-elevator function of holding the nose up. The same force under the stab-elevator plus the keeping the airflow over the stab-elevator holds that wing into its angle-of-attack to keep the wing loaded and the nose up. Just taking the throttle off will stop all the good stuff and KER-PLUNK! It is a constant of slight back pressure as the model slows and the nose rises ever so gently. One needs to FLY the airplane until it STOPS. Lazy does as lazy is.

vertical grimmace

My Feedback: (1)

I was perusing one of my great books the other day "Stick and rudder". I was reading about landing, and avoiding "bounce". One very interesting point by the auther was that a taildragger is supposed to be "3 point" landed, because if the landing gear length were properly designed , then it will place the wing at the proper angle of attack to stall properly. Stalling the wing properly is the key to no bounce landings.

The reason why I am elaborating on this, is because poor landings with the popular warbirds at my club have become rampant. I have been trying to explain that they need to learn how to stall their planes, but this is falling on deaf ears. I recommend to take it high, and do stall tests to get a feel for what it will do. Many RC pilots seem to be afraid to fly too slow near the ground. Granted, you can get too slow, but you have to get properly slow to land correctly. This window seems to be narrower with a heavy warbird, but it is still necessary.

Top_Gunn

My Feedback: (6)

Interesting thread. I recently finished a somewhat modified Touche, a Dave Platt design from a very old Pica kit. All through the build I kept thinking "this really looks like a model airplane." Now I see why I thought that: Big wing with a fat symmetrical airfoil, long thin fuse, and a small vertical stab (made up for by a lot of vertical area under the tail). Not that it was a converted control line plane, so far as I know, but I'd bet that it looks that way because the designer had a notion of how models should look. The looks may have been at least part of what influenced me to finish it with silkspan and dope instead of a film covering.

(Haven't flown it yet because flying season is over here.)

vertical grimmace

My Feedback: (1)

I remember when I was first exposed to modern Control line combat, around 1990 or so. I was so blown away by the performance, and still, to this day, do not see aircraft that operate in the envelope that a combat aircraft does. The keys to the design were very light weight, large wing area, Powerful engine, and a medium thick airfoil. The light wing loading, which with our design was around 11oz., could turn so tight and change direction so fast, it was more than most pilots can keep up with. Especially at 120 mph. The thing that is so impressive is how much angle of attack that could be achieved before the stall occurred. This was due to the light wing loading. Those aircraft to this day are still my favorite designs and the most fun to fly, even though I have now moved on to giant scale aircraft. The lessons learned in those days of heavy competition, had a profound impact on my modeling.