Found a new Trim tool - I think👍🏼

[Paul Taylor]

I’m not very good at trimming but I know enough when the plane comes lose that it needs something.

For giggles and grins I asked ChatGPT to provide a solution to a trim problem.
It gave me a very solid list of things to try and they seemed spot on. My guess it has digested Brett and Paul’s trim charts. 🤣

I would be curious if some of the experts can trip it up.

[Ken Culbertson]

I am like Roger Rabbit when it comes to stuff like this so I had to bite and entered this:
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My PA model airplane looses line tension on the 2nd corner of the hourglass maneuver, how do i fix

What I got was this:

It sounds like your model airplane is struggling with maintaining line tension during the hourglass maneuver. Here are a few things you can try:

Adjust Tip Weight: If your plane loses tension on inside maneuvers but not outside ones, you might need to add more tip weight to balance it out.

Modify Line Sweep: If additional tip weight doesn’t help, increasing line sweep could improve tension control.

Check Centrifugal Force: The control system relies on centrifugal force applied to one line in tension. If the other line becomes slack, it might be affecting maneuver stability.

Inspect Wing Alignment: If tension is lost equally in both directions, steaming the wing to adjust its shape might help.

Would you like more details on any of these fixes? Let me know how your next flight goes!
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Close? Not even.  I think I would rather rely on Paul & Brett - Ken

[Paul Taylor]

I would think tip weight and LO adjustment would help some?

[Brett Buck]

I am like Roger Rabbit when it comes to stuff like this so I had to bite:
-------------------------------------------------------------------------------
My PA model airplane looses line tension on the 2nd corner of the hourglass maneuver, how do i fix

It sounds like your model airplane is struggling with maintaining line tension during the hourglass maneuver. Here are a few things you can try:

Adjust Tip Weight: If your plane loses tension on inside maneuvers but not outside ones, you might need to add more tip weight to balance it out.

Modify Line Sweep: If additional tip weight doesn’t help, increasing line sweep could improve tension control.

Check Centrifugal Force: The control system relies on centrifugal force applied to one line in tension. If the other line becomes slack, it might be affecting maneuver stability.

Inspect Wing Alignment: If tension is lost equally in both directions, steaming the wing to adjust its shape might help.

Would you like more details on any of these fixes? Let me know how your next flight goes!
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Close? Not even.  I think I would rather rely on Paul & Brett - Ken

   That's a disturbing set of errors!

      Brett

[Howard Rush]

That’s who’s driving my car!

[Ken Culbertson]

Here is what I got when I tried the AI's solutions: 

Ken

[BobTheBuilder]

While reading an article originally published in Flying Lines (NW News) and also featured in Model Builder magazine, I noted a relevant observation:


   2025 Edit: Adjusting tip weight can help resolve line tension issues, particularly in high-altitude maneuvers. If the airplane feels “loose” during a figure such as an overhead eight, adding a small amount of tip weight may help. In some cases, both tip weight and leadout rake must be adjusted in tandem to fully optimize the trim.


Furthermore, Paul Walker’s trim chart (Criterion #4: Tension All Around?) specifically calls for evaluation and adjustment of leadouts, tip weight, engine thrust, offset, and rudder alignment as part of resolving line tension concerns.


Given these respected sources, it’s difficult to justify excluding leadout rake and tip weight as integral variables in the discussion of tension management. Their interaction with aerodynamic balance and yaw stability directly affects the aircraft’s ability to maintain outward pull—especially in vertical and overhead maneuvers. Therefore, any comprehensive trim analysis should necessarily include these two elements as fundamental contributors.

I see no response on how these two variables have a negiative impact on said issues.

[Ken Culbertson]

While reading an article originally published in Flying Lines (NW News) and also featured in Model Builder magazine, I noted a relevant observation.....I see no response on how these two variables have a negiative impact on said issues.

All quite true but read AI's reason for recommending it: If your plane loses tension on inside maneuvers but not outside ones.  First they affect both inside and outside and the 2nd corner of the hourglass is decidedly outside.

Ken

 

[Ken Culbertson]

This is getting interesting.  I posed the same question to see if AI had learned anything.  On my last post on this thread I corrected their assertion that tip wieght and leadout position only affected inside tension.
When I posted the question again my post was the first item in the Google search and the AI's new answer read:

Adjust Tip Weight: If tension is lost equally in both directions during loops, adding more tip weight could help stabilize the plane.

Spooky - Ken

[Brett Buck]

While reading an article originally published in Flying Lines (NW News) and also featured in Model Builder magazine, I noted a relevant observation:


   2025 Edit: Adjusting tip weight can help resolve line tension issues, particularly in high-altitude maneuvers. If the airplane feels “loose” during a figure such as an overhead eight, adding a small amount of tip weight may help. In some cases, both tip weight and leadout rake must be adjusted in tandem to fully optimize the trim.


Furthermore, Paul Walker’s trim chart (Criterion #4: Tension All Around?) specifically calls for evaluation and adjustment of leadouts, tip weight, engine thrust, offset, and rudder alignment as part of resolving line tension concerns.


Given these respected sources, it’s difficult to justify excluding leadout rake and tip weight as integral variables in the discussion of tension management. Their interaction with aerodynamic balance and yaw stability directly affects the aircraft’s ability to maintain outward pull—especially in vertical and overhead maneuvers. Therefore, any comprehensive trim analysis should necessarily include these two elements as fundamental contributors.

I see no response on how these two variables have a negiative impact on said issues.

    Adding tipweight generally aids line tension in either direction. This is probably AI misinterpreting my post here or elsewhere indicating that you have to make the airplane safe to fly before you can start doing anything. But the reasoning is wrong in context - if you have a lot of tension in one turn direction and not the other, it indicates that you have warp or tweak somewhere. It is not an indication of inadequate tipweight, or at least it is not the place to start.

   similarly, the last suggestion is:

Inspect Wing Alignment: If tension is lost equally in both directions, steaming the wing to adjust its shape might help.

    Which is just plain old wrong, "steaming the wing" to "adjust it's shape" will cause the airplane to gain tension one way and lose even more the other. The soluition to "tension lost equally in both directions" is to "add tipweight". Tweaking it will make it worse - leading you back to either losing tension (which might end you up as Ken illustrates...) and having to go back to the first solution, throw in excess tipweight just to compensate for your now warped wing, at which point you wull have to straighten back out.

    And - good luck steaming a balsa-sheeted epoxy-finished foam wing to tweak it, it will self destruct long before you get it hot enough to warp. Even pouring boiling water into a towel wrapped around it (which will work for a sheeted built-up wing or other structure) will, at best, cause the sheeting to delaminate from a foam wing. I have a bad feeling about what steam/boiling water would do to a carbon-fiber/epoxy wing shell. ut I haven't tried that. Normally you tweak the flaps, not the entire wing, just because stunt wings are built so stiff that you can't safely reshape them once they are built. Built-up, silkspan/polyspan open bay, maybe.

     So, typical of LLM "AI" (which is not really AI in the classical sense) it got some words from somewhere and attempted to assemble them in a logical order, but missed the context and/or details.

    Brett

       

[Paul Taylor]

My experience with ChatGPT, the more information given the better the results. Also if it gives what I feel is wrong information I challenge it and it will apologize and then give a better more accurate answer.

Granted it’s not as good as having Brett or Paul sitting under a shade canopy at your circle. 😎

I do have a few coaches, but sometimes a guy just has to fly when the weather is right. 😁

[Brett Buck]

My experience with ChatGPT, the more information given the better the results. Also if it gives what I feel is wrong information I challenge it and it will apologize and then give a better more accurate answer.

Granted it’s not as good as having Brett or Paul sitting under a shade canopy at your circle. 😎

I do have a few coaches, but sometimes a guy just has to fly when the weather is right. 😁

     On general topics, it will usually get a decent "consensus" opinion about whatever the topic might be. The quality/accuracy depends on what they trained it on. Whether the general consensus on that topic is correct or not is where it tends to get in trouble. Just look at the "general consensus" on many topics here (engine selection and setup), for example, where the consensus/majority is mostly ludicrous nonsense. It will dutifully spit that out.

     Or, say you had it in 1955, it would tell you that the notion of plate tectonics or the continents moving around over time is a ludicrous fringe conspiracy theory by someone who isn't even a geologist. And that South America and Africa happening to have shapes that fit together nearly perfectly is just an odd coincidence. It will state something with utter confidence whether it is right or wrong, as long as most of the training material supports the idea. In this particular example, you would have gotten the same idea from almost every knowledgeable person as well.

    That is the most basic fundamental flaw with LLMs that I am aware of. We have tried various inquiries on work topics, and sometimes it is right on, and other times, it is absurdly wrong. The problem is *you can't tell the difference* unless you just know better yourself.

    Brett

[Paul Taylor]

Yea its not there yet but I think it mostly collects data then regurgitates it back. It’s a shot in the dark at times.
I have asked it to generate a photo of a plane and get all kinds of weird looking models. 🤣🤪

[Motorman]

I have asked it to generate a photo of a plane and get all kinds of weird looking models. 🤣🤪

Maybe they are planes for robots.

MM

[Dennis Moritz]

No hourglass in senior pattern. I think. But the outside triangle. The nerve of those folks.

[Gerald Arana]

No hourglass in senior pattern. I think. But the outside triangle. The nerve of those folks.

I'm not up on the new pattern. Are the outside triangles pointy side up or down!

Jerry

[Don Jenkins]

I'm not up on the new pattern. Are the outside triangles pointy side up or down!

Jerry

According to the Brodak Senior Challenge post, the outside triangles are point down.

Don

[Ken Culbertson]

Thought it might be good to repost the specs.

https://stunthanger.com/smf/open-forum/brodak-senior-challenge/msg682683/#msg682683

My only thoughts are that the outside triangles are a bit too easy to be replacing the hourglass.  A lot of us have used that maneuver to unwrap lines.  One thing I really like is the < 60 degrees instead of 60 +-.  My roots are East Coast and I get docked repeatedly for flying too small.  Just like everything else, 45 is much larger in Texas!

Ken