CAD Verification

[dz1sfb]

Just been doing some verification to see if I am understanding the plans correctly. 

Two items are;

1. The control stick assembly. The plans do not specify where along the aileron torque control tube the stick is to be mounted. I ended up placing it midway between the station 2 lower cross tube and the lower seat cross tube.

2. Motor mounts in station 1, I am just showing to see if this looks like I've understood the plans appropriately.

[scottiniowa]

I see what you mean, (on the stick placement)  and I don't recall this discussed. This of course is a little bit of a "feel good" part.   i.e. if it feels good at a certain spot, then call it good. The problem of course, is doing a perfect scale mock up.  1" fwd or reverse does not change the action as you know.

Perhaps there are those that can do a quick measurement, tell of placement and their human body size.  Not to many adjustments here.  (only padding thickness of seat)

Now on the CAD work. Good job.   We built the front fire-wall frame the opposing way, so taller than wider.  This allowed us some more knee room and more narrow profile in this area, this of course does not change the spacings of the mount holes.  Just an option.

Also I don't know if you have capabilities for color, but I often like to have all of one size of tubing a certain color, and then the next size a different color, that way you can quickly look at and get a informal look at the basic requirements for tubing. Just a thought.

Did you stick with plans width for seat area? or narrow this up? certainly debate-able numbers.  NO right or wrong way, just preference.

Good job!

[914pete]

Thanks for these drawings Ken.  Very helpful.

[dz1sfb]

I see what you mean, (on the stick placement) and I don't recall this discussed. This of course is a little bit of a "feel good" part. i.e. if it feels good at a certain spot, then call it good. The problem of course, is doing a perfect scale mock up. 1" fwd or reverse does not change the action as you know. Perhaps there are those that can do a quick measurement, tell of placement and their human body size. Not to many adjustments here. (only padding thickness of seat) Now on the CAD work. Good job. We built the front fire-wall frame the opposing way, so taller than wider. This allowed us some more knee room and more narrow profile in this area, this of course does not change the spacings of the mount holes. Just an option. Also I don't know if you have capabilities for color, but I often like to have all of one size of tubing a certain color, and then the next size a different color, that way you can quickly look at and get a informal look at the basic requirements for tubing. Just a thought. Did you stick with plans width for seat area? or narrow this up? certainly debate-able numbers. NO right or wrong way, just preference. Good job!

One thing I will do with the stick position is to determine how much fore/aft stick displacement there is. Try to get it about even. I don't recall seeing a recommended control throws for the tail surfaces. This is controlled by the rudder and elevator stops, but I would like to have the control stick optimally placed for balanced movement and minimal binding against the 3" pulley as the stick is pushed forward. 

I wonder if it is less stress on the control system to put stops on the stick and pedals versus at the surfaces? Control stops at the surfaces allow straining the cables once you hit the stops.

I will play station 1 by rotating to vertical orientation. I am about 6' 1" tall and my shoes are 12" long, Going vertical may be a good move. Spacing on motor mounts is per the plans, and I have used the dimensions given as centerlines of tubes, even though sheet 8A would indicate that the 13-1/2" x 11-1/2" dimensions appear to be to the outside of the tubes. Those same numbers are specified on the fuselage sheets 4 and 6 and are called out as center to center dimensions on sheet 6.

On the different colors for different size tubes, you've already done a great job on that, and too many colors get very distracting to me while I am working on the tube. So I color by materials, steel, aluminum, and plastic. I usually like a graduated background, but this seems to be working well. It is distinct without being too contrasty. Otherwise it bugs my eyes.

The seat area is 24" center to center width.

I really enjoy building the job in math first. My primary job is a metal model maker, then CNC programmer, and CAD designer. All this translates into my hobby business, and projects like the Legal Eagle. It's been my practice to know and understand the plan before I start cutting and building. My employer appreciates it too.

Glad the images can be of help. I am resisting the urge to modify and build stock per plans first, unless there really is an issue. I rather put in the minimum and keep it 103 legal, then add on later. The only know deviation at this point that I will pursue is the center mounted wing section fuel tank.

[joecnc2006]

I found this, maybe someone can confirm.

The generally accepted rule of thumb on ultralight control surfaces are:
Ailerons    20-26 degrees up,  0- 15 degrees down
Rudder     15-30 degrees vane travel
Elevators  20-30 degrees up,  15- 20 degrees down

[dz1sfb]

A quick question I have is concerning the horizontal stabilizer. Do the root ends of the leading and trailing edges get butted together inside the stabilizer connectors that are shown on sheet 19, or is there clearance between them? and if there is clearance, how much?

[joecnc2006]

This will depend on your build capabilities, you will find there is a little differences. I placed mine as far in as possible but ensuring the hinges leading edge was 90° from the fuselage (see red line). It does not matter if there is a little space between the two halves, you are drilling and bolting it to the 4130 towards the outer section of the support pieces. and will find on the elevators horn side you will have to offset your drill hole.

I Also measured from a fixed forward center point of the fuselage to the outer most rear point of the Horizontal stabilizers to ensure they are equal. The more care you take will only benefit you later on.

I also see you added a 3/4'? piece onto the top of the 7/8" rear vertical piece, I just side the 3/4" Vertical stabilizer into the 7/8" 4130 and did not need any extra pieces, it is then just drilled and pinned into place.

[dz1sfb]

I also see you added a 3/4'? piece onto the top of the 7/8" rear vertical piece, I just side the 3/4" Vertical stabilizer into the 7/8" 4130 and did not need any extra pieces, it is then just drilled and pinned into place.

Joe,
I understand this to be in reference to the tail post.  What I have modeled here is a 3/4" diameter tail post, with a 7/8" diameter tube on top as shown on sheet #25. I could have done a 7/8" for the entire tail post as that is called out as an option, but did not.

A bit more study of sheet #19 shows the elevator connector to be 4-1/2" long. That's an indicator that there should be 1" between the ends of the stabilizer halves. Not that is necessarily critical, but it helps me knowing what it ought to be. That will also align my mounting holes.

[joecnc2006]

With me as well as a couple others i have read you will more than likely shave a little off the 4-1/2" length, don't forget fabric/glue will come into play so you do not want it to be snug against the elevator gusset. Also I would drill the mounting holes when you have everything fixed and in place. not before, this will make sure they are perfect with each other, Its fine to draw in cadd and get everything lined out but its another to pre-drill things before assembly, I found it better to drill in place.

[Doug Tipps]

All this is incredibly helpful as I walk through the build process assessing whether I have the skills it will take to build a DEXL. What a great group! You may not have a good feel for how much I am learning from this site. Thanks a million.
I have talked to Leonard on the phone and since I only live about an hour and fifteen minutes from him he invited me down to visit the "shop". I'll order my plans and pick them up when I go.

[dz1sfb]

All this is incredibly helpful as I walk through the build process assessing whether I have the skills it will take to build a DEXL. What a great group! You may not have a good feel for how much I am learning from this site. Thanks a million. I have talked to Leonard on the phone and since I only live about an hour and fifteen minutes from him he invited me down to visit the "shop". I'll order my plans and pick them up when I go.

Just a heads up I just received an email from Barnstormers that someone was selling an unused set of LEXL plans for $60. Here's the copy;
LEGAL EAGLE • $60 • AVAILABLE FOR SALE OR TRADE • Trade Unused Legal Eagle-XL plans for Legal Eagle LEU plans. Or sale • Contact Michael L. Velemirov, Owner - located Akron, OH USA • Telephone: 330-785-3322 • Posted June 3, 2016

Might be helpful, but probably not as helpful as seeing Leonard and his shop.

[joecnc2006]

I went to Leonard's house and took cash to get the plans for the LEXL, HalfVW, and all his videos. I have visited him twice since then, when i have been in the area.

[dz1sfb]

Got around to playing with the rudder horn today. I really prefer the pull points in line with the hinge axis.

[scottiniowa]

Got around to playing with the rudder horn today. I really prefer the pull points in line with the hinge axis.

Excellent,
 I didn't sit down and do any math...by making this configuration , does anything change? such as length of travel?  Looks good.

[dz1sfb]

 Excellent, I didn't sit down and do any math...by making this configuration , does anything change? such as length of travel? Looks good.

Here are some linear dimension comparisons between the two horns, I used 30 degrees as the value for rudder deflection and yielded the following  results. Only the rudder horn was rotated in these screen captures.

So far I am liking the numbers. +13.61mm sideways cable displacement keeps the cables running smoother through the fairleads.