Cool
 

Rc Universe has been one of my favorite sites for all the racing and engine forums, now they have a discussion fourum for my favorite type of model plane !

RE: Cool
 

Welcome to the Control Line forum and enjoy!

RE: Cool
 

Cool they named a forum after me :)
Think Ill have to make me up an animated control line plane for my avatar though.
:)

RE: Cool
 

All I can say is YAYYYYYYYYYYYYYYY...finally...a forum for the kind of flying I enjoy most of all :D

RE: Cool
 

DU:

Should I point out that the part you like best is never having to walk more that 60 or 70 feet to pick up the wreckage?

Haw.

Bill.

RE: Cool
 

Real Airplanes have Two Engines...and Two Wires [8D]

George

RE: Cool
 

George:

Good one. Almost.

Don't forget Victor Stanzel's fantastic invention for we who flew c/l speed - Monoline controllers.

And while I still have a bunch of two-line stuff, my Monoline equipment is all gone.

Bill.

RE: Cool
 

I heard rumor they were going to ban monoline in speed competition.
Any truth to that?

RE: Cool
 

It seems to me that I saw something about banning Monoline in Model Aviation, but I don't think it will happen.

The use of Monoline is firmly entrenched, and there's nothing inherently dangerous in it.

Some things, like the tetra fuel additive we were using in 1960 and 1961 are extremely dangerous, not only from being explosive but highly poisonous. Banning tetra and other corrosive fuels was a good thing.

In my opinion, and the opinion of everybody using it, banning Monoline would be a bad thing, and just plain senseless.

Since that one note several months ago I've heard nothing more.

Bill.

RE: Cool
 

Monoline is not only for Speed. A few years ago at the Vintage Stunt Championships Dale Kirn showed how to use Monoline in a stunt plane. Then his son flew a stunt plane using Monoline. One of the interesting points (to me) was how the wires would retain some twist to the point that he would have to spin the knob to reestablish neutral while the plane was in level flight.
I have an old Stanzel class A unit and a class "A" size Kansas Twister. That said, I have never flown speed and never used a Monoline unit. :)

George

RE: Cool
 

ok guys i am an ooollllldddddd 2 liner. could somebody give me a short class in "monoline"??? how the heck.....does that work......... i can't seem to get my tiny brain around it. of course i have never seen it either!



john

RE: Cool
 

Mono Line was around in the 50's and eversince I guess. It was made by Victor Stanzel if I remember correctly. The only places I saw it used was in the speed classes.

The handle was made like a Yankee screw driver and there were two handle parts. A fixed one at the rear and one that slide back and forth. To slide the one back and forth caused the line to twist. There was a mechanism in the plane to convert this twisting motion into uup and down on the elevator.

The line was two or three times thicker than one of the two line types.

It didn't work so well for stunt.

Jim

RE: Cool
 

Flying Monoline gave you about as much control feel as using the Aramid lines for a two-line system, or flying yur 1/2A Cox RTF with the supplied thread lines.

Very mushy.

Dale Kirn was one of the few who could make Monoline look good on a stunt plane,

One of Stanzel's seling points was retaining control when the plane came in on the lines. My opinion? If you lose tension on the lines you have other things to worry about.

There were some real advantages, for example if the plane pitched up the line would be twisted into some "Down" elevator input, so long as you held the slider in the same position. This is also why you see the pilot hitting the slider with the palm of his hand now and then - when you do an inside loop, for example, the line has to take that same full turn to stay in the control center position. And you have moved the neutral position of the slider about three inches closer to the handle, so you have to twist it back to the center of the spiral.

Unlike a two-line system where you just swing yur handle and keep the same control setting throught the maneuver, with the Monoline you have to keep moving the slider as the airplane goes through its maneuver, or the control goes back to neutral as the plane turns.

All this makes Monoline ideal for c/l speed. You don't want any pitch instability, Monoline adds a bit of stability all by itself. With two lines on a speed job any twitch of your hand will deflect the elevator increasing air drag, and lowering your speed. Doesn't even have to be enough to see, it's there.

A properly trimmed speed plane will "Groove," and maintain its five to eight foot altitude with no control input. Once you are "Grooving" you can take your hand off the slider and make no more control inputs all the way to the airplane landing.

But sport and stunt? No Monoline for me, thanks anyway.

Bill.

RE: Cool
 

Monoline was introduced for speed (where the rules didn't specify 2 lines) because the drag from the single line was much less than for two (thinner) lines one behind the other.

RE: Cool
 

well guys that is about a concise report if i ever saw one! thanx i can now visualize how this system works. all this time i was playin around with 2 lines tryin to go fast when i coulda been goin really fast!!!


thanx again

john

RE: Cool
 

DU:

Disagree, sir.

Jim Walker had patented the two-line system, all the manufacturers of kits or c/l parts, the bellcrank, control horns, etc, had to pay a royalty to Walker for every thing they made and sold. Monoline was an alternate system, and no royalty to Walker was required.

When Stanzel put Monoline on the market, in the mid 50s, he pushed its use as a sport system. He even hired Dale Kirn to go on a "Road show" to demonstrate it as a system for stunt planes. He was able to use line lengths that would not have been operable with a two line system,

One of the things he touted was just that, the longer lines. By using them, one of the "Newbie" objections was countered - the pilot spinning around. "I'll get dizzy!" was a common objection, the longer lines meant he didn't have to spin as fast.

And then the speed boys found that one 0.018" line was less air drag than two 0.012" lines.

So the Monoline system, intended to displace Jim Walker's "U-Control" never caught on, except for U/C speed,where it became dominant.

Bill.

RE: Cool
 

When I watched the video on this page it apeared they were using a standard handle. Does anyone know if that was a 2 line or single line used when that record was set.

http://www.flyrc.btinternet.co.uk/re...ntrol_line.htm

RE: Cool
 

Additioally, Stanzel offered a thousand bucks (50's bucks!) to anyone who could win stunt at the Nationals using a Monoline system. Noone won the money.
The actuator units for speed and stunt are different. The stunt one looks sorta like a spiral and the speed one looks like a worm gear.
There is a Stanzel museum in Texas (with a web site) for more information. I think it is owned and run by Dale Kirn.

downunder, I really like your graphic. Kinda reminds me of me when I had hair and was young enough to party all night :)

George

RE: Cool
 

What is the advantage of the single blade prop?

RE: Cool
 

ControlLine:

Watching the video, and taking a cropped image (attached) sure looks like he was using a two line system.

Hearing the engine come on the pipe sends chills down your back, doesn't it?

Bill.

RE: Cool
 

Jess:

Any prop has to turn, obviously. And the less disturbed the air it turns through, the more efficient it can be.

When you have only a single blade there is no air disturbance from the other blade to go through, so efficiency goes up.

And this is why, generally speaking, a two blade prop is "Better" than a three blade, and it naturally follows that a three blade is "Better" than a four blade, and so on.

Three and four blade props are used on full scale planes to limit prop diameter mainly, but also for noise supression.

The disadvantage of a single blade, other than the counterweight, is the offset thrust load on the crankshaft.

Bill.

RE: Cool
 

Bill....thanks for the correction on Monoline. I can't even imagine trying to do a square using that system although I don't think they were even thought of back then :)

The advantage of a single blade prop is that you can have a large enough disc area to generate the thrust while keeping the load down on the engine so it can reach the revs needed for maximum HP. In that video he's definitely using 2 lines because Monoline is banned for FAI speed. In fact, they're not even allowed to use "groupers" which were used to keep both lines close together to reduce their drag. The fuel he'll be using is a simple 80/20 with all castor (that's why it's called FAI fuel :) ). The handle locks into a pylon so that the radius is constant and to prevent any whipping. Timing starts (I think) one lap after the handle is placed in the pylon because they have to whip like crazy at first to get the engine to unload enough to come on the pipe.

RE: Cool
 

DU:

That shows you how much I really know aboutFAI regs. I knew the fuel was 80/20, but I didn't know they could not use Monoline.

I never bothered with groupers in two-line speed, just put 10 or 15 twists in the lines, not only holds them together but cuts the frontal area way down too, where they are one in front of the other. Yes, it makes the control a little stiffer after the speed comes up, but if you have a good flight you're already grooving and no control is needed.

Besides, I always figured line pull was wasted power. My engines were always installed with left thrust, and left turn built into the rudder. Sometimes got a little too much, and the first flight could be exciting.

My one surviving speed plane is a 1/2A, totally different from current designs. Built it in 1960.

Bill.

RE: Cool
 

The Stanzel Model Aircraft Museum is is owned and operated by the Stanzel Family Foundation. It is in Schulenberg, Texas, on Hwy 77 about 5 blocks south of I-10. There is a website, but I don't have it. They have a new website because their former website was taken over by a porn outfit. Dale Kirn has built a number of magnificient airplanes for the museum and the museum itself is very well done. There is either the original Thunderbird, or a replica, which Dale twith promoting monoline for stunt.

Dale's son, Joe, flew a Jamison Special on monoline at the 2000 VSC (I was an OTS judge) in a very respectible fashion. Dale told me Joe had only been flying monoline for two weeks, and had not previously flown CL.

We are planning a speed-limit CL combat contest in Schulenberg for October 2004, sponsered by the museum.

RE: Cool
 

i have a question about 1 blade prop.

people are talking about how disturbing an unbalanced prop can be

so is this prop balanced how??

RE: Cool
 

I think there is a small counterweight on the opposite side of the hub.

RE: Cool
 

A propellor blade is far more efficient traveling in undisturbed air. This is why a helicopter requires more power to hover that to climb straight up. This relative inefficiency is caused by the trailing blade operating in the air disturbed by the leading blade. And of course, every blade of a prop with two or more blades is both a leading and a trailing blade depending on your point of view.

This traveling in undisturbed air is one of three definite advantages of a single bladed prop. The second advantage is being able to use a larger diameter, the larger disc area also conveys greater efficiency.

The third advantage is one people don't think about until they start flying speed, with belly landings on the paved runway. No matter how carefully you position the prop on the engine, you are going to drag one on the ground every now and then, and this will ruin the prop for max speed runs. Might still be OK for practice flights after you rebalance it. With the single blade set to come on compression in a vertical position you'll never sand your prop on landing.

The two major disadvantages are the counterweight, it has to be a lot heavier than the second blade would be since it's very close to the hub, and all the thrust exerts a side load on the crankshaft bearings, increasing the wear..

Hope this satisfies your curiosity about the props with one blade missing.

Bill.

PS: For my general flying I think a two blade prop has a blade missing - I like three-bladed props. wr.

RE: Cool
 

Hate to say this cause usually I agree with Bill, but the effeciencies of a single blade prop has nothing or little to do with disturbed air. As the aircraft is moving foward or even on the ground the air that the prop has disturbed is moving behind it, that is one reason why you have to add right rudder on take off, the disturbed air is spiriling around and hits the top left side of the rudder turning the plane to the left. Since the disturbed air is behind the plane the next prop blade is in clean air no matter how many blades are used. The reason less blades are more efficient are two fold. The drag of the blade tips are very large, more blades more loss, the area where the prop goes into the spinner is another smaller loss that is affected by the number of blades. In fact if you use a ducted fan this loss is greatly reduced and you can increase thrust by adding blades right on top of each other such as used on jet turbine engines. The other reason is as downunder described, the more blades the smaller the prop arc, the area of the prop arc is more important than the blade area for generating thrust. More area is more efficient. However sometimes when going really fast, such as around 400 hp you have to reduce the disc diameter to gain more air velocity and add more blades, though most multi blade props are used simply for prop clearance.

RE: Cool
 

Hugh/Sport:

Your points are valid. I tried to stay as simple as I could. But I did address the radius/diameter in talking about the propellor's disc area.

And with sufficient airspeed even a 30 blade prop would have each blade entering undisturbed air. You will notice please, my counter example was a hovering helicopter with essentially zero airspeed. And when pitched for max air speed the inefficiency has a very bad effect on the airplane's accelleration, and running out of fuel before comong "On the pipe" isn't uncommon, all because the prop doesn't work very well at low speeds.

A good example is my old "Royal Rodent." On a paved or smooth clay circle it will take off, and run 140 mph in the air, using a 9x8 "Rev-Up" prop. On grass it wont take off with that prop. I have to switch to a 10x6 just to get off the ground.

Bill.

RE: Cool
 

Interesting to note that the top four finishers in Open CL Precision Aerobatics at the last Nats used three-bladed props. Is there something about disc density which hasn't been mentioned here?

RE: Cool
 

Do you suppose anyone has tried a ducted fan CL speed model? I know they probably couldn't enter a contest but I would think someone has experimented with them.
I remember someone using a fan to supercharge their air intake. This was back when speed flyers were experimenting with tuned intakes (late 50's?).

George

RE: Cool
 

Jim...that's something that's been bugging me for some time now. I seem to recall there was some esoteric advantage to using a 3 blade in stunt (other than ground clearance). I think it had something to do with when turning a hard corner the thrust distribution wasn't affected by the slightly different blade angles presented to the air by the upward travelling blades compared to the downward travelling blades due to the angle of attack of the model during the turn. I tried a search on SSW some time ago but I'm guessing I didn't put in the right search term :(

RE: Cool
 

DU:

What comes to mind for me is the decrease in the precessive (gyroscopic) forces exerted, and this is due as much to the smaller diameter as anything else.

But I don't know if this was/is a consideration.

Bill.

RE: Speed Record Video
 

Finally got around to viewing the video using the computer at work. Holy Cow!! One lap every 1.15 seconds or so. I've seen a little racing before but never have been at a big contest where they were flying speed. Hope to see jet speed flown one of these days although I don't think they are as fast as this little speedster. The sound is supposed to be unbelievable though.

RE: Cool
 

Woweee that sucker really jumps up when it hits the pipe doesn't it? Last time I heard such a difference was when a certain dirt bike came up on the pipe when I wasn't expecting it, and I have the plate in my hand to prove it!

Aspect Ratio is why one bladers work better than multibladers, just like in Sailplanes, High aspect ratios deliver maximum lift for minimum drag.

3 bladers on PAMPA ships? Lets remember what they are dealing with, and I am going on speculation here but. They are dealing with a power band, delivered at a certain rpm on a certain pipe with certain fuel. This combination probably dictates a maximum diameter, multiple bladed prop to absorb and deliver the power at the correct rpm so that the engine can get up and down on the pipe at the ideal flying speed. Things evolve and everythgin is a compromise. I've no doubt that if the proper power band could be hit with a 2 blade prop, that'd be the way everyone would be going, it's cheaper and easier to install, trim and balance than a 3 blader. But I bet the wash from a multi blade prop is also more constant instead of the choppyness of a lesser bladed prop.

Or it could just be that a 3 blader looks cooler.

Aspect Ratio, that's the key though. Next is the Tip Vortices that was mentioned before, only one set on a one blader.

RE: Cool
 

Most 3 blade props have the same or nearly the same aspect ratio as the two blade props.

RE: Cool
 

Yes, but a 3 blader with the same aspect ratio as a 2 blader loses more, whats more, if you swap from 2 to 3 blades the standard practice is to go down in diameter, lower aspect ratio effectively. Remember, air molecules do not get any smaller. With the same power, with less props, you get to have a longer prop, higher aspect ratio. Oh sure, you could have the same diameter prop and make it one wide blade, but they don't work quite as well due to the tip vortices covering a larger portion of the blade. I suppose it's a chicken and egg thing. Induced drag is what you are trying to get rid of, you do that by going to a more efficient wing, higher AR wings, as long as you can get on your airplane for the other aspects of the design, are what you go for. This is why the Corsair has those bent wings, trying to get as big a diameter prop on it while keeping it out of the dirt, and there is just a bunch of horsepower in that big ole Radial, more than when it started out. Happened on the Mustangs too, that's why with the Allisons you saw the skinny 3 bladders and on the later models with more power they went to those big ole paddle sized 4 bladders, gotta suck up the power.

Least that's what the videos and text said when I was in college, but, it was Tech college so I'm no aerodynamicists, they could've be dumbin things down fer us simple folk.

RE: Cool
 

Back in the 30's there was a single bladed propeller used on J-3's & other light planes , manufactured by the Everell Propeller Co. Increased speed , climb & fuel economy . It was quite unique as it was pivoted on an angle that automatically changed pitch in relation to power & speed . Be a real mind bender at a scale meet ! MAX H.

RE: Cool
 

No doubt you've all seen this single blade prop on this World Record FAI ship. The link has been posted everywhere, but if you haven't seen it, it's a pretty cool video.

http://www.flyrc.btinternet.co.uk/re...ntrol_line.htm

RE: Cool
 

Hey Plane:
Your avatar looks like most of the guys around here after they've lost one!
Haw.
;)littlefly