WINANS

Quote

"I learned FF, then CL, then R/C. (with lots of crashes !)

I know some great R/C Pilots that are actually 'spooked' at trying CL !!!"



Hi Crosscheck,

I learned similarly, first CL, then FF, then RC. I think FF is the real training ground. You have to both think ahead and think and watch after the plane leaves your hand to truly understand what is going on with the plane, and what to alter to affect it positively. It's a true aerodynamics training ground, if you choose to approach it that way. CL is great for the visceral feel it provides.

Funny that some would be afraid of or aprehensive of CL isn't is? Maybe it's a bit different from the days of half-A control liners in the local park or school yard and a cheap and fun way to be flying. However, it can still be done very inexpensively (homemade cardboard ariplanes with pine motor mounts is what worked for me in the 70's). It's just fun to be thinking and talking about it. This thread is a fun one. Thanks Puerco del Combate.

Scott

combatpigg

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I don't understand the apprehension with control line planes, either.......

Rendegade

What do you do if your receiver browns out?

I guess you change your pants.

Mr Cox

I never understood CL, and went from FF directly to RC, even before we had lightweight radio stuff.
The idea of a plane flying around a centre point is too much like an airborne tethered car to me. I just itch to cut the cord and set them free...

combatpigg

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I wanted to experience flight, but couldn't afford RC. C/L at least was a way to get to play with engines and get familiar with how planes fly. Since the advent of RC, C/L has evolved into a competitor's hobby and RC inherited the casual flyers.
There is some "sport flying" going on, but most C/L flyers are working towards some kind of a goal nowadays.
With task oriented categories, you can enjoy the pursuit of the perfect engine set up, prop, airframe and then practice to execute the correct manuevers, or actions to fly a perfect pattern routine, or fly a knock down, drag out, combat match, or maybe put everything together "just so" for a record speed run.
An interesting website to look at is "Flying Lines" to get a snap-shot of what's happening in NW control line.

combatpigg

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Just a "blog entry" more than anything tonight.
The plane flew perfect right off the work table today.
The CG was moved forward slightly per Jim Thomerson's advice. What I did was grind down the steel control horn until it is 1/4 of what it originally was. The plane grooves nicely on the level.
The leadout position was spot on. Just behind the CG. I glued the adjustable block in place and covered up the wingtip.
The wingtip weight was just enough to tip the balance outboard and that was enough.
These 20 pound test Spiderlines are nearly weightless and practically invisible, too.
The plane pulls these 50 foot lines nice and tight through the entire routine.
After the engine quits, the glide is good enough for me to get about 1/2 of a lap to choose a landing spot. Wouldn't want to see this plane any heavier.
The 2 inch line spacing at the handle worked well with the 2 inch spacing at the bellcrank. If the handle is cranked hard, the plane will respond pretty tightly. I never did get it to stall.
I tried to get some video, but even with a zoom backed all the way off there were only short glimpses that were worth looking at. The allignment of the camera was set too low and I ran out of day light to play with that any more.

ProBroJoe

Right on brutha!!!

I bet one of the tiny "keychain" or "gumstick" video cameras attached above (or below) the leadouts on the wingtip (pointing back to the center of the circle) would provide an interesting perspective of the pilot.

combatpigg

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Joe, the wing-cam would give an interesting look..!

I might make up a set of 60 foot lines and head down to the control line area at our local airport to see how that goes. Flying this thing at 50 feet makes it seem like it's right there in your face.
Flying at 60 feet is riskier, I'm not sure how many 1/2A planes have tried it.
The was a guy back in the 1990s who flew a gigantic stunt ship with a TD.049 that was angled way out to the right...maybe 15 to 20 degrees..? The plane was extremely light for it's size and IIRC, he flew it on 60 foot lines and competed with it against .35-.40 sized planes in precision stunt.
What can happen with a plane that has marginal pull is it can cut across the circle with the lines going slack, then make a course correction that snaps the lines after it takes up the slack. So on a windy day, something like this is more prone to happen.

BMatthews

Lovely job on that model CP. And yes 15% is a good starting point for the CG. You may find that you can move it back a little but likely it won't be much. Go back too far and it'll get too prone to wanting to overshoot and will become very touchy to fly well with a groovy style.

As for weight I know that 15 oz was a good target for the diesel combat models that I used to fly. And I was able to build a 16 oz .15 stunt model version of the Jr Magician back in my teens which flew well. And the wings on those were up around the same amount of area as your 240 sq inch size. So if you're flying on 52'ish foot lines don't expect to be able to fly slowly with a two to four cycle stunt style engine run. With the .074 you're likely going to need to peak or near to peak out the Norvel and then use the prop diameter and pitch to get it to fly at around 50'ish mph to ensure adequite line tension. An online control line speed calculator tells me that this means you want around a 4.2 second lap or lower to ensure you get to 50 mph.

I just noted in your last post that you want to try it on 60 foot lines. I really would not suggest it for a smaller model with this size engine. The weight of the lines combined with the light line tension you'll have will produce some funny control effects where the inertia of the lines wants to keep going instead of stopping when you move the handle. This model needs the shorter 52 foot length combined with .012 wire. Hell, if you know you can be careful with the lines I'd even say .010 would be better.

Andrew

If CP is using 20lb Spiderwire, line diameter is about .009" . The EZ Braid Spiderwire is pretty incredible stuff with almost zero stretch and lighter than equivalent diameter steel.

combatpigg

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Thanks Bruce.
As it turns out, the Norvel running on muffler pressure seems to flood itself out if I don't keep it right at the edge of a full scream. It's also mount upside down, which might contribute to that.
The venturi allows 17,000 rpm with a 7x3 prop, pretty much identical to the stock carb

Your're right about this size and weight of plane having a comparable feel to the British Diesel planes that we flew with 8x6 props. Those we set at 64 mph or under....mine would never threaten that mark.

Andrew is right about the Spiderline...this stuff is practically weightless. I guess the drag is comparable to the same gauge of steel. If I try 60 footers, I'll approach with caution. If it works, the reward is pretty high. This time of year we have alot of dead still days without even a breeze, so no time like now to experiment.

BMatthews

The drag issue with the Spectra line would be my only concern. But with a nominal size for the 20 lb test stuff at .009 it sounds like it fits the bill in every manner. Certainly weight or mass wise they fill the niche most excellently. And a spool of the stuff is cheap enough that you can have a set for 52 and one for 60 foot line lengths and just chose based on the wind conditions of the day.

I look forward to hearing about the flight results.

combatpigg

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Bruce...funny you should ask....[&o]...looks like this will be a "reverse" build thread...[I needed a new project, anyway].

I made up a set of lines that put the center of the model 60 feet away from the handle grip [actually about 58 foot lines from end to end]

Went down to the park and gave it the old college try. The plane immediately came right at me after it cleared the launch ramp. I'm not sure if a line was snagged in the grass, or not...but the plane snapped both lines as soon as it regained line tension and this is where probably 99% of the damage occurred. The plane went straight in at basically 0 mph 10 feet off the deck.
So, it could have been much worse.
If the lines weren't snagged in the grass, then the extra weight and drag of the lines were just too much for the amount of thrust. If there was some wind, that could have been used to some advantage to keep the lines tight at launch, but this plane would have been challenged to negotiate the upwind part of the circle.

Jim Thomerson

My thought on stunt airplanes is that the engine is set to run its happiest. The prop is selected to fly the airplane at the speed at which it is happiest. The line length is a compromise between having enough line tension and a comfortable lap time. Top stunt fliers say that can tell a difference with a change of six inches in line length.

Line length in feet x number of laps x 4.285/ seconds = speed in MPH.

So, one can determine how fast the airplane is flying; and, using simple algebra, how long the lines need to be for a particular lap time at that speed.

combatpigg

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I wonder what kind of power it would take to fly on 100 foot lines...?
The biggest set up I ever flew was a Dick Sarpolus design with a Royal .50 on 70 foot lines.
At 70 feet, I liked the illusion of depth...that there was a plane that seemed like it was WAY out there faithfully chugging it's way through my commands at a fairly slow pace.

vertical grimmace

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CP, sounds like a classic case of not enough tip weight. The tip weight is essentially needed at launch, and counteracts the weight of the lines. This causes the inboard wing to drop and fly in at the pilot on launch. Once the aerodynamics take over, the tip weight is not needed. I have never been sure of exactly how to calculate the amount of weight needed, but I surely have experienced this situation when I did not have enough.
I always used pennies on my combat models. I would always get asked why I used pennies. I would reply, " I could not find anything cheaper"!

combatpigg

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VG, pennies ARE cheaper than just about anything else you could try using. I think they sell penny sized washers for a dime now.
I should try adding more tip weight and go for it again......[>:]
I drill holes in the wingtip, channel a groove that bridges from hole to hole and shove a "U" shaped piece of lead solder into both holes until it is flush with the surface, then cover with a patch of monokote.
The original tip weight was just right with the 52 foot set up, so I'll probably tape a nickle or a quarter on and give that a try....better to have too much than too little initially.
If that fails, then I'll just admit that I should have listened to Bruce...!
I just think it would be too cool to have a 1/2Aish plane that could get er done on 60 footers.

Andrew

It really sounds like one of the lines had snagged. Spiderwire is so limp that you can get swags anywhere and it seems to be more prone to hanging on stuff. At least the damage was minimized.

andrew

Jim Thomerson

There is an airplane called the Stratoliner, I think, which has two McCoy 049 diesels, one in the usual place. The other is on the outer wingtip pointing out at @ 45 degrees. It was published in Model Airplane News. I think I have a full size plan somewhere. It was flown on 100 ft lines.

Crosscheck

Hi CP,

ALWAYS, blame it on the 'Stooge' launching it ! You mentioned 'clearing the ramp'...?

Glad it is repairable. The 'spiderline' broke? I thought it was bulletproof? Never had that happen with the 1/2A dacron line...

Way back when (70s), I had a 'Jim Walker U-Reely' handle. (wire lines for .19/.35) It was very heavy, but the lines were stored in the handle and you could adjust the line length.
(It had a 'pin lock' for the crank, and if you were careful, you could adjust it in flight ! )
I remember 'letting the lines out' to full length(60ft?) on a McCoy .19 profile job, on a calm day...
The extra drag on the lines made the plane 'tilt in'...[X(]
You should have seen me 'stepping back', whipping, and cranking that handle back in ! ! !
Yes, I repaired it, and it flew again. The Beauty of CL ! ! !

Hey CP, I'd like to Thank You[8D]

Thanks to you, I am now a Balsa Beaver...[8D][8D][8D]
(I got to the meeting !) It was Awesome ![8D]
More stories later, and lots of Fun to be had !

I work at a Small Craft Brewery, and I am 'testing' our Smoked Oatmeal Stout, India Ink IPA, Black Creek Porter, etc...

While looking for that box... I 'know' has those 'Perfect' bellcranks !

Friday the 13th...

Take care,
Have fun,
Dave'croaacheck'Fallowfield
Maac 6437
Unabashed Combat Team

combatpigg

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I'm certainly no expert on rigging, but I'll bet it's a pretty exact science based on math.
I suppose the practical thing to do is to stretch out a run of X length of the cable of your choice, then measure the amount of effort it takes to keep that run of cable somewhat taught.
Once you know what that value is, then you could begin to figure how much outward thrust you will need to maintain line tension.
As a starting point for wingtip weight, I suppose you need to balance out X% of the entire control line system. This is whare I wonder if a "Rule of Thumb" has ever been worked out..?
Jim, that's pretty interesting that it would require just that much force to keep adequate tension on 100 foot lines, but I'll bet the relationship between line length and the thrust required to make it workable isn't linear. That must have been a quite a sight, but I can't imagine being about to do any stunts...!

combatpigg

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I'm not sure if I should hope if that was the case or not..?
These lines are very hard to see, so it's hard to scan them all the way back to the plane.
Catch 22 is, if you pull back too hard on the lines to keep them out of the grass, then you will pull the plane into the launch ramp and screw up the prop before it has a chance to take off.
Sounds like I'll have to enlist my wife to launch and she doesn't work for cheap...[]

Andrew

Mine won't work at all and she's still not cheap!!![:@]

Crosscheck

Hey Andrew,

The Gals who can, and like hand launching...

Are Very Expensive !



Take care,
Have fun,
Dave'crosscheck'Fallowfield
Maac 6437
Unabashed Combat Team

skaliwag

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Times are tough .. but a "Hand Launch" shouldn't cost that much .. No?