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  #16  
Old 10-29-2010, 12:51 PM
argoldman argoldman is offline
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Default Re: Canard Dat File vs Templates F and G

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Originally Posted by mfryer View Post
Being the owner of the wing that Marc O. helped me cut, and also a Eureka customer, I can't help but chime in....


Yes it was (all three times I have done it, once helping a Cozy builder and both of my wings).


I tighened down the wire everytime just before we began. Still there was some lag, I beleve a little lag is unavoidable, however if you follow the plans instructions that lag shouln't be a major factor.


I don't quite understand what you are trying to say here. Are you suggesting that any lag is unacceptable, or if the two people performing the hot wire opperation must impossibly be exactly at the same position or the operation is a failure?? Also unless you are cutting a canard ALL the templates are different sizes and shapes... so what?


My experience (while limited) leads me to be sceptical that heavy pressure on the template will significantly reduce wire lag unless your wire is way to hot and loose (you don't want to go there, or do you....). As so many here like to say YMMV.

Marc helped me cut a "good" set of wing cores. And then we had a beer and a hill (couple cans) of beans for dinner (really). Marc left before reparators were nessisary.

I purchased my canard cores from Eureca. I was very happy with them. However after helping Steve Parkins hotwire one of his wings, I just couln't justify buying my wing cores. I can definatly see the advantage of time savings and I imagine the quality of his cores are probably better than my hand cut cores, but I am happy with the ones I cut myself.

If someone wants to save a little time and money isn't a factor, buy quality premade cores. But I wouldn't talk anyone out of making there own.
Thanks for chiming Mfr,

I agree that lag shouldn't be a significant factor, and is unavoidable, however it is a factor of some sort, and may be one of the main factors for the necessity to spend so much time in the microing and smoothing of the wings. Of course, a less than ideal wing will fly, as Marc Z so aptly puts it, "a barn door will fly if given the right amount of power" (paraphrased --to avoid marc's fury - )

My purpose was not to talk anybody out of cutting their own, but to look at some of the possibilities of relating home cut to CNC. If this is true, and makes sense to some, perhaps I (we in our discussion) have saved somebody hours, weeks, months..... of finishing, for a few bucks (BTW, I have no idea of the additional cost of cutting the cores is).

My assumption is that the templates were designed from the concept that a wing (canard) shape was desired. Since the cores are not a continuous block,the templates were designed to, if nailed to the appropriate size cores, and an absolute straight wire (no bow) were dragged across the templates, exactly at the appropriate numbers, cut out the "proper airfoil.Since the template design was probably done mathematically with no compensation for wire bow and jerkyness of the operator, and not done experimentally. Anything other than the above initial considerations will necessarily cause errors. significant????? unknown since we fill in the errors with micro.

I'm glad that you tighten you wire. However any lag (unavoidable, probably also in the CNC will cause errors. and it "shouldn't be a major factor, especially since we fill in our "minor factor" errors with micro.

As far as the templates being different shapes, and "SO what""--

Well lets take a look. If you have a small template on one side and a large template on the other side, the person at the large template must move the wire faster than the one at the small one to produce a good product. The difference of the sizes and speed has the ability to increase errors That's what the numbers are fore. Perhaps when you cut your three wings, you and your counterpart were exactly in synch (as a CNC) would be, however having been there, each of you has to be somewhat erratic due to body rhythms such as breathing and heart beats, muscle fatigue etc. and instead of a smooth movement from one part of the template to the other, what you have is a series of short jerks, uninterpretable to you or your partner, but t here none the less. One of the reasons you call out the numbers is to notify your partner to speed up or slow down his progress to match yours.

Of what importance is this.

Assume that you have a wing shape with the leading edge to your right (partner's left) If you start at the trailing edge (for this discussion) and for some reason your partner has a brain fart and does not move at all until you are finished with your side, you will get a nice smooth, in effect semi-conical wingish shape. Now if your partner becomes unfarted, and you restart the process from the same initial point and do it perfectly, you will notice that a lot of foam does not get cut because too much was cut away by the prior experience. If you start at the leading end, the errors will be different, but present none the less

If your partner only has a semi-fart your shape will be closer depending on the amount of beanage. The degree to which the two partners are in unison will determine the trueness of the shape, to the templates, to a degree determined by the relative correctness of the relative movement.

As I said before, these errors, small tho they may be, are corrected with micro in the finishing process.

My hotwire saw has two movable handles around the wire, which allow the operators to place downward or upward pressure directly on the templates to maximize wire tension.

My point is not that hand cut cores are unacceptable, when certainly they are acceptable and have been used successfully by the majority, but that perhaps the CNC cores will save an incredibly amount of finishing time

(all conceptually since I have no experience with the CNCs)

Let us all know how long it takes you to finish your wings vs a similar area on your canard.
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  #17  
Old 10-29-2010, 01:29 PM
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Default Re: Canard Dat File vs Templates F and G

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Originally Posted by argoldman View Post
My point is not that hand cut cores are unacceptable, when certainly they are acceptable and have been used successfully by the majority, but that perhaps the CNC cores will save an incredibly amount of finishing time
The time savings involve more than finishing (which I don't believe is significant)
All of those details Torque tube cutout, electrical cutout, inboard FC1 Cutoff, Aileron cutout, leading edge cutoff (in prep for the shear web) all done before you open the box ....... the first time.

I spend a lot of time building alone. It's a pain to try and coordinate with someone else's schedule to get the hotwire going. Good on the folks that do.

..... so my point is you will not notice a time savings once you get to the step where you layup the shear web. The time savings comes prior to that step.

You may experience a slight weight savings due to the parts fitting together better.

There is a level of precision missing that starts when you try to match up the pieces of a template drawing to make the complete template from which to cut your cores.

To YMG's original intent (and you really shoeld get yourself a name) I would prefer to start out with a CAD plotted drawing of the full templates and work from there than to try and come up with a reasonable template based off of two and sometimes three different drawings on paper that have aged 20+ years.

I try and draw out my ideas in CAD and then plot out the results full scale on a ploteer I bought specifically for this project.

At this point (if I were buying a new set of Cozy plans) I would expect plotted drawings. I don't know if they have gotten to that point or if AeroCanard is any different. I know my Long-EZ drawings were lacking by today's standards but you can see in some of the beautiful examples out there ...... it didn't make any difference to most.
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  #18  
Old 10-29-2010, 01:47 PM
Lynn Erickson Lynn Erickson is offline
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Default Re: Canard Dat File vs Templates F and G

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Originally Posted by TMann View Post
The time savings involve more than finishing (which I don't believe is significant)
All of those details Torque tube cutout, electrical cutout, inboard FC1 Cutoff, Aileron cutout, leading edge cutoff (in prep for the shear web) all done before you open the box ....... the first time.

I spend a lot of time building alone. It's a pain to try and coordinate with someone else's schedule to get the hotwire going. Good on the folks that do.

..... so my point is you will not notice a time savings once you get to the step where you layup the shear web. The time savings comes prior to that step.

You may experience a slight weight savings due to the parts fitting together better.

There is a level of precision missing that starts when you try to match up the pieces of a template drawing to make the complete template from which to cut your cores.

To YMG's original intent (and you really shoeld get yourself a name) I would prefer to start out with a CAD plotted drawing of the full templates and work from there than to try and come up with a reasonable template based off of two and sometimes three different drawings on paper that have aged 20+ years.

I try and draw out my ideas in CAD and then plot out the results full scale on a ploteer I bought specifically for this project.

At this point (if I were buying a new set of Cozy plans) I would expect plotted drawings. I don't know if they have gotten to that point or if AeroCanard is any different. I know my Long-EZ drawings were lacking by today's standards but you can see in some of the beautiful examples out there ...... it didn't make any difference to most.
where do you think the cad drawings came from? they were plotted from a set of the original hand and then copied drawings, even the berkut ones garbage in, garbage out.
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  #19  
Old 10-29-2010, 02:46 PM
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Default Re: Canard Dat File vs Templates F and G

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Originally Posted by Marc Oppelt View Post
And you might want to add some casters to the bottom of those winglets...or at the very least - skidplates.
You mean like they do on a Piper low wing?
Quote:
Originally Posted by Lynn Erickson View Post
where do you think the cad drawings came from? they were plotted from a set of the original hand and then copied drawings, even the berkut ones garbage in, garbage out.
You only need to get one profile to a state of perfection. The subsequent templates can be scaled from that at a level of precision that reaches down to .0001 inches (which is a good starting point.)
If you've ever worked with the CAD tools, you could see the advantages they offer.
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  #20  
Old 10-29-2010, 05:18 PM
ymg ymg is offline
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Default Re: Canard Dat File vs Templates F and G

Quote:
Originally Posted by Lynn Erickson
where do you think the cad drawings came from? they were plotted from a set of the original hand and then copied drawings, even the berkut ones garbage in, garbage out.
Lynn, this is the point about using the DAT file. I believe the data was given or at least confirmed by Roncz himself.

Quote:
To YMG's original intent (and you really shoeld get yourself a name)
I do have a name but you'll need to twist your tongue. How does Yves-Marie sound and that's only the first name. For the nickname I'll wait until I become a flyer.

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  #21  
Old 10-29-2010, 08:12 PM
argoldman argoldman is offline
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Default Re: Canard Dat File vs Templates F and G

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Originally Posted by TMann View Post
The time savings involve more than finishing (which I don't believe is significant)
T,
Have you finished a set of wings?????



Let us know when you have
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  #22  
Old 10-29-2010, 08:23 PM
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Default Re: Canard Dat File vs Templates F and G

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T,
Have you finished a set of wings?????

Let us know when you have
The last skin layup on my right wing was applied last night. (Wing & Winglet)
I'll move it to my 2nd table to finish the layups around the torque tube, etc.
The jigs will be set up this weekend and I'll get started on the left wing.

This will allow me to work on finishing the wing surface or the right wing while I'm waiting on cures on the left wing.

Shoot .... I may run out of glass work someday if I keep this up.
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  #23  
Old 10-29-2010, 11:57 PM
Buly Buly is offline
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Default Re: Canard Dat File vs Templates F and G

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Originally Posted by TMann View Post
Shoot .... I may run out of glass work someday if I keep this up.
I would not wary about that. I have been flying for 4 year and still doing fiberglass work. These planes are never finished.
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  #24  
Old 10-30-2010, 12:50 AM
ymg ymg is offline
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Default Re: Canard Dat File vs Templates F and G

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I would not wary about that. I have been flying for 4 year and still doing fiberglass work. These planes are never finished.
Buly, I saw your plane at the last RR and I would certainly be happy with that level of completion.

Besides your quotation about the happy childhood says it all, these planes are toys, so we toy with them and building is probably a large part of the fun.

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