Size difference between LE and LE XL

[Dave Stroud]

Got my plans today and spent some time going over them. I've become curious of the size difference between the cabin area and overall length of the XL and the standard Eagle. If someone gets a chance could you please say the following dimensions of the LE ? Lower longeron between stations 2 and 3 up to the top center tube where rear spar attaches. Front to back measurements from station 1 to 2 and 2 to three on lower longeron and finally the  dimension from station 2 lower longeron back to the tailpost. Thanks....Dave

[Tom H]

Dave, these are from a quick look at old notes on our LEU (don't build one from these numbers!!!):

- vertical distance from the lower longeron plane to the fore/aft tube at the rear wing mount is 43.5"

- horizontal distance on bottom from St 1 to St 2 is 21"

- horizontal distance on bottom from St 2 to St 3 is also 21"

- horizontal distance along bottom from St 2 to tailpost is 134"

Hope that answers your questions.  I don't have the XL plans, so I'm interested in the differences, please let us know.

[Dave Stroud]

thanks for the quick reply, Tom. I'll show here my dimensions from my XL- F80 plans. Something doesn't seem right or there must be some open license to more or less do as you want.

On my XL plans, the vertical distance from the lower longeron plane to the fore /aft tube at the rear wing mount is 41 3/4" (  shorter )

horizontal distance on bottom St1 to St 2 is 24 1/4"   ( so we see more leg room )

horizontal distance on bottom from ST 2 to St 3 is 21 1/4"    ( not much difference there )

horizontal distance along bottom from St 2 to tailpost is 133 1/2"   ( a bit shorter  )

I don't know what to make of this and want to get working on the fuselage asap. Any and all ideas appreciated. Thanks...Dave

[Tom H]

Not too much difference.  Surprised on the headroom dimension.  On our LEU, Treehugger, we had to make a fairly long engine mount (bed mount on ours) to get the flying CG in the right position.  So, with the St 1 to St 2 being a bit longer on the XL, the mount would not have to be as long.  And, the extra legroom would be nice.

I suspect that parts of the plans were drawn up in final form after the prototype airplane was built, and measurements were taken.

And yes, you definitely have some leeway in how you build.  Just don't get too extreme.  Build as close to the plans as possible, measure and fit for anything that is not exactly defined.  Keep the extras off, keep the weight as low as possible.

[Dave Stroud]

You say not much difference Tom and that is my concern. Your plane is a ELU and mine is a LEXL which should be larger...certainly longer.  it has me thinking that I may have a drawing from the LE and not the LEXL. Our fuselage length dimensions are almost the same. My XL drawing shows 133 1/2" from Station 2 back to the tailpost and your dimension is 134"

On page five of my XL plans where I have been taking my numbers from, the overall length of the welded fuselage structure is 157 3/4". Leonard's intro page on my plans says the "Fuselage Length is 193"  but he doesn't specify if that includes the rudder and or the engine. To me a fuselage is just that...no rudder, no engine included.

Thanks for your input, Tom. Do any others who may be reading this have drawings of the LE and LEXL plans that could advise what the length of the bare welded fuselage structure is ? Thanks.

[Dan_]

Station 1 is 24 inches.  Station 2 is 24 1/2 inches on XL # 33 plans page 6.  158 inches overall for bare welded fuselage...

[PropMan]

The main difference is the XL wing has considerably more area and is built a bit stronger.  The XL fuse is wider and has larger tubing in certain places.

[Dave Stroud]

Something is just not adding up on my plans...XL F-80. Reading sheet 6 numbers from right to left...and we counted  8 stations in total with number 8 being the tailpost, , on my plans the first bay from station 1 over to 2 is 24 1/4". The next bay from station 2 to 3 is 21 1/4", the next bay from 3 to 4 would be 30.75" ( by subtracting 81 1/2" from 112 1/4" on page 6 ) , then 4 to 5 would be 23", 5 to 6 would be 24", 6 to 7 would be 17" and finally 7 to 8 ( tailpost ) would be 17 1/2".

So Dan, what is the length of your third bay, please ? I'm wondering if that bay gets reduced in length to compensate for the second bay being longer than mine.

Thanks for your comment too, Frank but most info on the LE and XL states that the fuselage is considerably longer on the XL. My sheet 6 does say overall length  of the fuselage steel frame only is 157 3/4" Thanks all.... Dave

[Dan_]

Something is just not adding up on my plans...XL F-80. Reading sheet 6 numbers from right to left...and we counted  8 stations in total with number 8 being the tailpost, , on my plans the first bay from station 1 over to 2 is 24 1/4". The next bay from station 2 to 3 is 21 1/4", the next bay from 3 to 4 would be 30.75" ( by subtracting 81 1/2" from 112 1/4" on page 6 ) , then 4 to 5 would be 23", 5 to 6 would be 24", 6 to 7 would be 17" and finally 7 to 8 ( tailpost ) would be 17 1/2".

So Dan, what is the length of your third bay, please ? I'm wondering if that bay gets reduced in length to compensate for the second bay being longer than mine.

Thanks for your comment too, Frank but most info on the LE and XL states that the fuselage is considerably longer on the XL. My sheet 6 does say overall length  of the fuselage steel frame only is 157 3/4" Thanks all.... Dave

Subtracting 112.5 from 81.5 gives 31...

My numbers from right to left are 24, 24.5, 112.5, 81.5, 59, 35, 17.5  (XL plans #33)

I'd get Station 1 and 2 like I wanted (biggest numbers)  Get the heights, and the numbers across the top right. 

The rest of the truss numbers don't have to be exact.

[Dave Stroud]

Thanks, Dan. Your numbers add up to 161" . 24 + 24.5 + 112 1/2 = 161 but above you say your plans indicate 158"overall. I give up on this subject. I guess you can pretty much build to any number you want. I'm just not used to that, hence my questions about the numbers. Regards...Dave

[Tom XL-7]

I checked page 6 on set XL-7.
I match your numbers exactly as you listed in the third post in this thread
my overall length is 157.75
24.25   21.25   112.25
The top line won't add up correctly. Look at the arrow for 104.25"
notice it doesn't point to station 3, just a little behind. Because that tube has a slight radius in it. It's the back of the seat.
Frank is correct; the big difference is an extra bay in each wing. Also a wider fuselage. it is not a substantially larger aircraft.
It was just a tweak to accommodate heavier pilots
There are also some changes that basically included some ideas other builders had used.
Oh and one more important change. 
The wing mounts on the XL are lower on the spar than the LE giving a little extra headroom.
Page 6 went through some changes early on.  quite a few different versions. That possibly explains Dan's numbers.
Tom XL-7
You are in fine shape
Don't give up on any subject until it makes sense.

[Dave Stroud]

Thank you all. I think I've got a grip on it. I'll likely go with 24.5 on both the first and second bays then 109 to the tailpost for a total of 158". While being conscious of what every extra pound can do, I'll likely turn this into a full cabin single seater something like Bodacious and have a cabin width of 26" center to center. Being mindful also of adjusting the geometry of a known product, I'll plan on entering the plane only from the right side but with a modification to the entry area tubing something like a Cub. I like the idea of a V lift strut arrangement and will try to do that with the Carlson streamlined tubing. I weigh about 180 and should be a little less so the extra weight allowance of the XL should allow me some extra tubing and a center section above my head. Another rib today and the aileron end plates. Nose ribs are ready. This weekend I'll get going on the spars.  Regards...Dave

[Tom XL-7]

I have a concern  with the V struts. Most negative and positive loads from the wing attach to the bottom fuselage points and cross tubes. Those bolts at the top are pivots.  The V strut arrangement reduces those points from 4 to 2.   I like the fact that the drawing has these attach points at a cluster in all cases. 
Sometimes you can find a proven example from a cub or what have you that would lend some guidance to borrow on both the attach points and the door modification
If you think about it that rear strut really doesn't affect you as much as you may imagine. So what? you have to step over it. 
I recommend not changing major things in a proven design but it is "experimental".
Another thought is that double top tube does not have to be full cabin width. The more you spread it the wider the wingspan and all the geometry from wing attach brackets and such changes. That steel bracket on the spar should be in line with the lower fuselage attach brackets. Linear loading,  The triangulation that shows up in the stations would be eliminated by a rectangular station. Added bracing would be prudent.

you really don't have to extend the  distance to station 3. It is under your seat. 

Just fuel for thought
Tom XL-7

[Tom H]

Dave, just for comparison, LEU plans #4-K (one of the earlier sets, maybe around 2001, I think) show the following dimensions:

There are 7 stations along the bottom longerons (that is, anywhere along the bottom longeron where structure tubing intersects).

Sta 1-2, 21"
Sta 2-3, 21"
Sta 3-4, 30-3/4"
Sta 4-5, 23-1/2"
Sta 5-6, 24-1/4"
Sta 6-7, 34-1/2"

The dimension on the plans from Sta 7 (tailpost) to Sta 1 (firewall) is 155".  The numbers above add to 155"; in agreement.

There is a 1/2" tube which supports the front of the seats that is 8-3/4" behind Sta 2, call it Sta 2A.  Don't know if you count this, or not.

And, also for comparison, the side-to-side width of the lower longerons in the area between Sta 2-3 is 19.5", center-to-center.

[Dan_]

Thank you all. I think I've got a grip on it. I'll likely go with 24.5 on both the first and second bays then 109 to the tailpost for a total of 158". While being conscious of what every extra pound can do, I'll likely turn this into a full cabin single seater something like Bodacious and have a cabin width of 26" center to center. Being mindful also of adjusting the geometry of a known product, I'll plan on entering the plane only from the right side but with a modification to the entry area tubing something like a Cub. I like the idea of a V lift strut arrangement and will try to do that with the Carlson streamlined tubing. I weigh about 180 and should be a little less so the extra weight allowance of the XL should allow me some extra tubing and a center section above my head. Another rib today and the aileron end plates. Nose ribs are ready. This weekend I'll get going on the spars.  Regards...Dave

Give this guy a call...  Let us know what numbers he uses.

John Bolding 281-383-0113
jhb478@yahoo.com