Also, what isn't widely understood is the mass effect of the line(s) as the plane accelerates at launch. Good ol' f=ma. All of the mass of the line is inboard of the thrust line thus tending to turn the plane into the circle. This was an especially troublesome issue in the early days of 21 Proto. Pilots have to really be on their game.

Quote from: bob whitney on October 26, 2018, 09:53:39 AM
at the time that the stanzel units came out back In the early 50's they were flying on Much smaller wire's and could move the lead out guide much further forward Ahead of the C/G as shown on their plans .with today's oversized cables need to be further back to keep the plane from torquing in ,also the need for the tip weight. working with the Cajun formula should work good
[/quote

I cannot, with a straight face, and do not, with my normal scary looks, lay claim to this work as being from my Cajun brain.  I am not that smart at all.

This, I will say. I may be the first to get it all written up in a spreadsheet. Lotus 123, remember that?

Remember, plagiarism is stealing from one source. Research is stealing from many sources. I plead guilty of research .

In light of current thinking, I think Stanzel just had it wrong, even with the smaller wires. I cannot think of an instance were leadout guide being forward of the CG is correct. I know we have seen examples of this in earlier days but no one ever said it really worked.

Aircraft CG and leadout guide position are the points that matter. Leadouts neutral to aft. Never forward.

As I said in a comment above, my current thought re leadouts is more concern for how the tank is effected, or is that affected?

I used this tool on the tethercar program and it got me over 200. That is where the tank thing came from relative to line rake. And, in a tether car, the tank is about all you got. It would take several pages to explain this whole thing.

Luke
.

well the horses mouth says that Dale Kirn, ( mister Mono line ) was the first to go 100 moh with a 1/2A .his leadout came out to a wire guide ahead of the wing
Bill (Uncle Willie ) wisnewski did 154 mph with a K&B 19 ,not to mention many more records .all his pink Lady's had aluminum wings with the wire coming out at the front edge of the wing and they balanced about 1/3 rd of the cord. as the lines got thicker and longer he moved the guide back .his later planes had the wire coming out almost in the middle of the tip.

We were talking line guide, not history. All the H&R airplanes were set up pretty well along those same lines, which was the line of thought at the time. If you read my comment in my last missive, I said, 'In the light of current thinking." I admit we were wrong in the setup of our machines but they set a few , 18 AMA records if memory recalls. Our 1/2A plane balanced beyond 50 % back thinking we were doing it right. We were wrong all the way. It took me a while to finally get it thru my thick head that the thinking at the time was wrong.

Drag from a yawed airplane is near the same, whether it yaws in or out. A truly competitive CL speed airplane is far from a rock on a string.

I enjoy competing with folks who have fixed thoughts. Makes outrunning them easier.

I usually will offer a comment regarding the rake program and its use. It is not correct, but better than a guess. It will get you started, the tweaking is up to the user. There are other influences in how a plane flies beyond how it hangs. No one is forced to use it .

As an aside to all this, as far as I know, Willie never held a World Record in that every time he put smaller diameter wire on, he never changed the leadout position nor balance and everytime, the plane slowed down. Yaw will bite, especially on an upright two winger.

At age 83, I have other issues to sort. Use it or don't. I ain't charging.

Luke aka The Horses Other End

Here's the 2 line iteration of my "Log Ride". Using the Cajun formula, I can easily determine my starting LO position.

The plane don't look like much, but it sure came out light.

That looks pretty fast just sitting there, Danish. So us California boys is gonna have to come up with some reasons why it won't be legal. Maybe the leadouts? Well, if it passes the mega-pull test, we'll think of something else....

Now I did listen to some of the aero guys up at the transonic wind tunnel up north. Your model will go faster if you sprinkle sand over the paint while it is still wet. Trips your boundary layer and doesn't add much weight at all. Trust me. All the fast models have it.

I've been listening to the discussion on the monoline setup and leadout rake angle for my trainer. I put the stuntmaster unit on an aluminum angle bracket, bolted thru the wing spar. So I can pivot the bracket just by loosening things up. I need to make a line guide next. I'm thinking I need a nylon bushing that I can clamp in different locations. The bushing would have to stay on the line, or else I need a split bushing. I can keep working on the fuse while I figure it out....

Divot

Quote from: Dane Martin on October 26, 2018, 06:00:46 AM
Well interestingly enough, I have an original dizzyboy kit and a McCoy 60 set up in a pan for it. It's in my near future goals.

(Shhhh!) You're welcome!
Get it going -- I was about to comment when I saw the DB plans. Good luck.

I use Bob Fogg's leadout program. How accurate the result is, will depend on how accurate you are when filling in the necessary information. It evens gives you the option of selecting one control line, or two. To get the most accurate result, you will need to know, or have a very good guess at the airspeed you intend to fly at. Accurate model weight (flying weight, not static) and inboard wing length to the models centerline are also required.

By typing in different model weights and airspeeds in the appropriate boxes, you can see how weight and airspeed for a given model affect leadout position. Using this program, I have found that the correct leadout position will always be behind the CG.

Regards, Les

Jake,

Where can this Fogg program be boosted?

Divot McSlow

McLeadout

I will email it to you.

Les

Dave

I can't email it, and I can't post it here because it contains an executable file. I will have to snail mail it to you, unless someone much more computer savvy than I has a solution.

Les

How is Bob Fogg's program different from the program on the NCLRA web page?

BB

Bill and all

Here is a screen capture of the program. As you will see, it is quite different than the line rake program on the NCLRA website.

Les

Les

Mother Nature, the Lady controlling most things we try to do, cares nothing about how long the inboard wing is when we are discussing line rake. Along with other parameters, she really cares about the distance from the line guide to the balance point of the vehicle in a tip to tip plane. With internal leadouts, the wing tip and line guide may be the same point. External lead outs will usually have a guide device not at the actual wing tip.

On a 1/2A proto the tip to tip balance point will probably be outboard of the C/L of thrust. An upright "conventional" vehicle with wings on both sides will probably balance fairly close to the C/L of thrust. My current A speed vehicle is a converted F2A machine, one inboard wing, laydown outboard engine, balance near to 2 inches inboard of  C/l of thrust.

So, again, and one mo time, I will say Mother Nature has little use for the actual inboard wing length. Only distance from line guide to tip to tip balance point.

I go away, again.

Luke

Luke

I didn't write the program, and the guy that did is a whole lot smarter than I.

Your post reads to me, that your method will place the line in the correct position relative to static model balance. Bob's program takes into account line drag due to size of line, speed of airplane, and weight of airplane, and supplies a measured location for the line that will allow the airplane to track the circle properly. If you were to use the program, you would find that the line exit point (leadout location) changes relative to all of these variables.

I'm sure that he wrote the program initially for his own use, and that being for use with Asymmetrical models with the line anchored at or near the thrust line.

All I really know, is that it works for me.

Cheers, Les

I seem to remember using Fogg's program back when Bill Nusz and I were working together. And that has been a while and a half. I miss him to this day.

My point is not to criticize the program at all but to try to tell you the airplane does not necessarily  rotate about where the line attaches to the airplane but about the balance point. Has nothing to do with static nor flight balance cause they are the same. The cg will change through the flight due to fuel burn. Never have weighed a charged battery vs run down one, so will not comment on electric. The points of interest for line rake are the cg of the airplane and the line guide. Where a bellcrank is mounted is of no interest to Mother Nature. The inner wing span is not mentioned.  The bellcrank could be mounted in the tail cone and still be made to fly very well. Structural limits apply here. And a measure of common sense. A sorely lacking commodity these days.

Where more work really is needed is in the jet program as the cg change is relatively large and weight is reducing through the flight.  So the rake is changing through the run. this is why I worry more about rake and fuel feed that I do about rake and acft yaw. This does not mean I don't care about yaw and ignore it. It is there so you best deal with it.

And relative to your comment about the program working for you. How you know?

Luke


 

Luke

"The points of interest for line rake are the cg of the airplane and the line guide."

Agreed, and since the line will have a rearward "Bow" or "rake" during flight due to line drag, where the line exits the wing relative to CG will determine if the model tracks the circle properly.
If our model speed is fairly constant, and it usually is during a powered speed flight, the distance measured from CG to where the line exits the wing will differ depending on the wing span of the model. On a short wing, the location where the line exits the wing relative to CG will be less rearward than with a longer wing, assuming the line rake is the same.

That is the only reason I can see for the inboard wing measurement.

Relative to your comment on the ever changing CG due to fuel burn during flight. I'm sure most of us, I do anyway, build the line guide on a speed model big enough to be able to insert a looped line end through the guide to attach to the control mechanism. Due to making the line guide a certain width for the given loop size of the wire, said wire will ride against either the front, or rear edge of the line guide during flight depending on how accurately the line guide was positioned relative to the CG. If the guide is positioned near, or at optimum for the model, then the width of the line guide should accommodate small CG variances without causing excessive yaw issues.
Obviously, if you use a line guide just big enough to insert the diameter of wire you're using, and then build the line end afterwards so that the line always stays attached to the controls, then any CG variances would be more critical to yaw.

"And relative to your comment about the program working for you. How you know?"

It may not be the last word in determining the line guide location, but it works better for me than what I was doing...

Les

I give up.

Luke

Luke

After re-reading all the posts again, (and looking at your line rake program) this time something stuck. I now understand what your talking about.

I had never considered, or even thought of measuring that aspect of model balance before. Being mostly a two winged guy, I always just balanced a model in the conventional manner and called it good.

I'm older now as well, and sometimes my eyes take longer to open. Thanks for hangin' in there...

Les

Les

Thanks for not giving up on me. As a Cajun, I should know better than to try to  to explain anything to anyone else when my hands cannot be seen.

I will not discuss how many years I have been trying to makes sense of this line rake issue. Some of it clears up, and then fades from memory and I have to start all over. Don't ever get old.

I was hoping you would sit and think about what I was trying to say. Glad you did.

This issue exists in 1/2 A protos also. Two wings but engine and tank offset outboard. Not too far because of less weight but should be accounted for.

I don't think I have ever handled one of the sorta new kind of jet layouts but just looking, there has to be serious shift in the balance point on them.

Keep on thinking.

Good Holidays to you and yours.

Do hope we cross paths again before time runs down.

Take care

Luke

Luke