Balsawings

Wouldn't the holes need to be the correct size for the phenolic tube rather than the wing tube? Or, is that the phenolic in the pics?

Bob

patternflyer76

The pictures are of the CF sleeve and the CF tube is inside of the sleeve...

Taurus Flyer

Kevin,

I was looking to your thread and the pictures.
Your King Altair seems to have a symmetrical profile so the lift forces do have nearly a fixed position on 0,25 MAC.
When I look to your choice to divide the wing on the third rib then the position of the tube (brown) has to be on 0,25 MAC from the outside part of the wing is my opinion. (yellow part in the picture)

It seems me that you use a more backwards position of the tube in the wing I see on your pictures.

What is your way of calculating the position of the tube in the wing? Aren’t you afraid of instability when transfer from normal flight to inverted?
Where do you mount the position dowel, near the LE or the TE of the outside (yellow) wingpanel?

I hope my question is clear otherwise I can try to give you more explanation.

Cees

patternflyer76

Cees:

I have a program I developed to find the aerodynamic center and neutral point of any wing type using MS Excel. I place my CG were I want it between the AC and NP. The closer to the NP the more authority the rudder and elevator has. I like it this way. Where I have placed the wing tube is where I like my CG, more aft then most like it. As far as the fully symmetrical wing, the plans and designer call for dihedral to be built in. This will effect the transition from strait to inverted flight, but I'll just have to deal with that and mix it out. I do not want to change the original design of the aircraft. When you say position dowel, do you mean anti-rotation pins??? If so I will have one in the TE and LE of each wing panel.

Hope this helped explain my position....

[8D]

Taurus Flyer

Hello Kevin,

The answer is clear, and I also understand that I did make the right question which is sometimes difficult to me.
Understanding that I was right seeing you did make the tube in the CG and I ask you why?
The only right place to me is the position I did draw in my drawing. on the line of 0,25 MAC of the outside wingpanel

It is a profit that the aerodynamic lift forces do have a fixed position in the wing, on 0,25 of MAC. (because it is a symmetrical airfoil!)
When you position the tube in this location there will be less or no torsion forces in the wing panel and dowels.

Your thinking of making the tube in nearly the CG doesn’t have anything to do with the aerodynamic forces of the wing.
As an example, think about a Canard type, the CG is laying in front of the wing! Or a tandem airplane, with the CG between the two tandem wings! Or when the swept back was more! Would you make the tube in the TE then? No.

I show you the side view of the wing and the forces, the result can be distortion of the wing between R3 and R 6 with the result of increase of the AOA when lift forces increase and perhaps problems of flutter! Of course this is theoretical, but it’s a warning because it’s also a wing without a clearly defined D tube I see.
See also my thread� Redesign and reconstruction of the Oldest Taurus on Earth�. Post 58 page 3

This is my extra information. A warning , not more then that.

Cees

patternflyer76

Cees:

I welcome your information about the possible torsion possibilities, but I have placed wing tubes further back then where this one is located and never had any problems. Do keep in mind that most of these planes I'm talking about are pattern planes, and are not flown in a 3D manner. It would make a difference when doing a lot of 3D high G moves over and over again. Although you could build-in reinforcements and survive. I see what you are saying, that there will be less force on the anti-rotation pins and torsion of the ribs and spars if the tube is placed on the 25% point of the MAC. Equal lift.[8D]

patternflyer76

Cees:

I was also thinking about your post. If I make the CG forward of my wing tube location, then I totally agree with you, but if the CG is right over my tube then this will eliminate or reduce the torsion problems that could or may occur. My aerodynamic center would be forward of the tube or spar as in any design. The aerodynamic center or MAC for a swept wing, is where the lifting force begins and can not change per the airfoil. Same thing with the neutral point, a point where the plane becomes uncontrollable if passed to the aft by the CG. The CG is where ever you make it balance between the AC and NP. As long as its between these two point you will be fine. Also 25% of the MAC is just a rule of thumb. Some say 30%. Its really up to the designer/builders style or taste. We will see how it handles once I'm done. If I have a failure I'll hire you as my chief engineer. Thanks

Taurus Flyer

Kevin,

It is clear for me that you do not understand my explanation.

The thinking to make the CG right over the wing tube is the wrong way of thinking. ( Another wrong rule of thumb!!!)
Because that will not eliminate the torsion forces.

Where you make your CG isn’t new for me either, you are not the first one, I do the same and not this way.
“Also 25% of the MAC is just a rule of thumb. Some say 30%. Its really up to the designer/builders style or taste.�

So,

25 % of the MAC is “not� a rule of thumb in the calculation of the point the lift forces affect, you know that. Every symmetrical airfoil nearly has this exact point on 0,25 MAC . Only with the airfoils with camber this point is going backwards with increasing of speed and decreasing of AOA.

Last try, Tandem plane HM 290, one CG two wings?
And now? These wing are in three parts ,see the green square at the bottom.
Of course the fixation is on more points around the with dots in the blue wings.
When you can explain me where you should mount your 2 tubes you do not need me anymore as your chief engineer! In the CG? ou only have one CG!

Your plane will fly, success. And when you have questions about this “ask�! This matery is a little bit more complicated.

Oh, and BTW the affect point of the liftforces of the second wing of this tandem plane goes to the LE when the speed increases (S-camber), the pivot point of the front wing is under the white dot, to help you.


Cees

patternflyer76

Cees:

I was just trying to be funny about the Chief Engineer thing. Sorry if it offended you, but I like keeping it simple and being funny at the same time. This is a model airplane and not a NASA space ship. I like it my way and that is how this model airplane is going to be built. If you like, look, but please stop trying to give me lessons in aerodynamics and pointing out what you call a problem. That is not the point of this thread. This is just a build thread that if people would like to see, then they can.

You seem like a very smart and bright person. I would like to get more information from you one day on your ideas.

Thanks for all your comments....

Taurus Flyer

Kevin,

I understand.

Succes


Cees

patternflyer76

I have made a little more progress in my spare time. I have cut the plans to fit the building table, and placed the ribs of the right wing panel in the wing jig. Also, I have traced the W3 ribs onto the 3/32" light ply pieces for the mating surfaces of the joint. Will post more as I get more done.

Thanks

patternflyer76

A little more progress. As you can see I use magnets to keep everything square. I use carpenters glue for the strong bond, and ease of cleaning, (a little water). It also gives you plenty of time to move things around until everything lines up. I plan on finishing this panel tomorrow. Finally some time to work on this bird!!! [8D]
Thanks

patternflyer76

A little more done.... I've got the top spar in and rear sheeting on, and the front LE strip also. I changed things up a little bit. Instead of using the 1"x1/4" and the 3/4"x1/4" pieces to form the LE I decided to only use the 3/4"x1/4" LE strip and sand it to the shape of the ribs. After that I can ad a 3/8" piece of triangle stock and round it off. It should leave a nice clean strong LE. This will allow for a solid surface for the LE balsa sheeting to be laminated to. I'm going to leave the center sheeting out and just cap strip the ribs. Light weight, light weight!!!!!! Once this is done it will be time to turn the wing panel over and install all the guts for the wing tube socket and servo compartment. Remember the W3 rib has been cut from 3/32" light ply. I will also be cutting lightening areas out of the W3 rib once the wing panel is structurally sound enough to do so. I also use Sigment for the LE area and cap strips due to the ability to sand and make a nice finish in the sheeting and LE joints. Wood glue and CA's leave a nasty ridge that will allow the balsa to sand away before the glue even starts to be removed. It looks terrible once finished if you try to sand those types of glue joints for a nice finish. I use wood glue for the skeleton area of the wing panel...

patternflyer76

A few more pics....

patternflyer76

Well, another busy week with no time to work... I did get the right wing panel upper side finished. I just need to install my servo mount, and reinforce the wing socket ribs around each socket whole. Also I will be installing the anti-rotation pins near the LE and TE of the panel along with reinforcements for them as well. The right wing panel has been taken off the jig, and await the above. I've included some pictures of the center section of the wing being started. More to come. Hopefully this week will be more productive then the last couple of weeks. Thanks...

patternflyer76

Center wing section being started.

patternflyer76

I have actually been able to work on the King this weekend. I was able to build the other wing attachment to the same point as shown prior. Hopefully two weeks from now the mid section of the wing and the bottom side of both attachment wing panels will be complete and ready for covering.

Sorry, no pictures right now. I will post some more pics as I get them for the mid part of the wing, and finishing the underside of the wing panels.

Happy building, soon to be flying.

airbusdrvr

How can you build an airplane in all that neatness??? You should have to work, store all your planes, and all the cabinets and storage inside an 8'X8' little space in the corner of your garage!Only kidding, of course!

patternflyer76

Hey Airbusdrvr:

I use to be in a lot smaller area then that at one time. The wife kicked me out of the sewing room where it was nice and warm, or nice and cool depending on the season, just small. I then had to move all the vehicles out into the driveway and take the garage over as a work shop, 22x20. This has been working good for a while for my personal stuff. I have a shop set up at a commercial building with plenty of room for my professional building and set up jobs, and I have a set up at my dads second garage, (where the King is being built.) We work on a lot of projects together when we have time. I believe the neatness comes from my years in the United States Marine Corps. Everything is done in a fine tuned military manner. No matter how perfect something is done there is till room to improve. Maybe this is why I'm attracted to precision aerobatics. High speed, Low drag.

Thanks for the humor....

kingaltair

My Feedback: (4)

Yes you really are a "neat-freak", but I really admire that. I look at my shop, and I just don't want to put in the effort it would take to get everything in its place and put away. About as close to clean as I get takes place just before I start a project. At least the big old drafting table is clean.

Keep up the work my friend....I may very well want to pattern my next King after yours, (if I can)

High speed, low drag.....buddy you have the wrong plane The King is SLOW...er speed, because of HIGH DRAG. But of course you know that.

Duane

patternflyer76

Hey Duane:

Hope everything is going well. You can have any of my drawings and mods I've done. We need to get some practice time in some day soon before the big Tar Heel Classic. I am going to rejoin ABA in late March or April. I just have not had the time that I was planning on to fly and build for myself since the first of the year. I've done a little setting up of my Intruder for the Expert Class. It is close to being ready, but it just is not wanting to cooperate with me on a couple of maneuvers. Maybe you could take a look, because dad has been so busy with his job he has not been able to go out with me and give any input. Call me anytime.

Thanks for your comments:

Kevin

patternflyer76

The wing is almost done!!!!!!!!!!!!!

Here are some pics of the building over the last couple of days..

kingaltair

My Feedback: (4)

Kevin

When are you planning to have the King ready? How is you Dad's King coming, and is he planning to be on the "circuit" with us this season? Looking forward to seeing all those "KINGS" out there. I guess this will be the year I lose the advantage of having the only King Altair at the contest.

Duane

kingaltair

My Feedback: (4)

Kevin;

Question: Is it really necessary to use the center wing ribs, (the ones inside the fuselage)? I'm no authority on plug-in wings so this isn't my idea or anything [8D], what I'm relaying comes from owning one of Dennis Hunt's Daddy Rabbits, and relating what he has done.

With the strength of the C/F tube, couldn't the C/F tube simply be anchored in each side of the fuselage, and use a ply doubler on each fuse side where the tube goes through. The only thing inside the fuse is the tube itself. There are two alignment dowels, (one fron, one rear) on each side that fit into corresponding holes in the fuselage, and keep the wing properly aligned.

That would open up the fuse center for placement of radio equipment and so forth, otherwise the wing itself is occupying that space. Those ribs, (inside the fuse) are not going to be sheeted, so do they really add any additional strength?

What do you think?

Duane

patternflyer76

I was trying to make it easier to travel with this big wing. I really did not want to modify the fuse. I could have closed in the fuse sides and had no wing saddle, and lifted the wings up to the thrust line and do it like you described with Dennis' DR. I did not do this due to more engineering, need for a top hatch, modification from original design, and time. If the wing is together as one I can still take the wing off in one piece with the wing bolts as it would be if built as a one piece wing. Remember, this is going to be a tail drag set up so the main gear will be CF and built into the fuse with a tail wheel in the rudder. All avionics will be set up as usual through the wing saddle area, and if everything is together I can just slide the wing panels off, load, and go. I could set the fuse and W1-W3 in the vehicle with the main gears and tail wheel supporting, and put the wing panels in their wing bags. Also the stab is on a tube and socket setup with incidence adjusters just like the WM intruder. Very important to me when I am setting a pattern ship up.

One more thing is that the center section W1-W3 on both sides will be fully sheeted. I just have not got to that part yet.

Kevin Clark