Not so legal Eagle XL?

[totoro001]

Hey all!  I've done some searching but maybe I'm not doing it correctly.  If this has already been answered I apologize.

I am a licensed pilot with my tailwheel endorsement and I thought it might be interesting to build an XL with full covering and maybe some light weight makeshift doors so I could fly it in the winter (I'm in MN) without turning into an ice cube.  Doing so would most likely increase the speed to beyond FAR 103 and would require me to get it numbered (which is just fine, so the title is a little misleading).  My concern is that I'm assuming with full covering it'll be more aerodynamic, and result in a bit faster cruise.  Unfortunately I'm not an aerospace engineer so my questions are, what determines VNE, and what would that really be for a LE XL?  I would hate to build and cover something and have it be fast to the point that the wings fall off or the prop has issues or something equally terrible happens that I can't even think of.

Maybe my concern is silly an unfounded.  In a perfect world I would end up with an aircraft that could cruise around at 70mph with some canvas/aluminum/plexyglass doors that could be removed on nice days.

Thoughts? Ideas? Blatant mockery?

Thanks in advance!

[Steve]

Hey all!  I've done some searching but maybe I'm not doing it correctly.  If this has already been answered I apologize.

I am a licensed pilot with my tailwheel endorsement and I thought it might be interesting to build an XL with full covering and maybe some light weight makeshift doors so I could fly it in the winter (I'm in MN) without turning into an ice cube.  Doing so would most likely increase the speed to beyond FAR 103 and would require me to get it numbered (which is just fine, so the title is a little misleading).  My concern is that I'm assuming with full covering it'll be more aerodynamic, and result in a bit faster cruise.  Unfortunately I'm not an aerospace engineer so my questions are, what determines VNE, and what would that really be for a LE XL?  I would hate to build and cover something and have it be fast to the point that the wings fall off or the prop has issues or something equally terrible happens that I can't even think of.

Maybe my concern is silly an unfounded.  In a perfect world I would end up with an aircraft that could cruise around at 70mph with some canvas/aluminum/plexyglass doors that could be removed on nice days.

Thoughts? Ideas? Blatant mockery?

Thanks in advance!

Bodacious found in the Yahoo Downloads: http://www.eaglersnest.com/forum/index.php?action=downloads;sa=view;down=57

[joecnc2006]

I have a HiMax and the VNE is 100 (see link below) it has the exact identical wings from that i can tell when i compared and overlaid the ribs I built for the LEXL with the ones in my hard set of plans for the Hi-Max. and I believe is the same wings on the MiniMax, airbike etc. Its a common airfoil used on many. The only difference they have a full aileron.
So as far as the wings IMO. they would be fine, and the struts are well laid out on the LEXL with the separate connection points at the fuselage. which would distribute the forces at those points instead of concentrated to a single point with V-Struts, I think Leonard did this on purpose to ensure that from what i gathered when i was at his house talking about doing a V-Strut configuration instead, which the final outcome I just said hey it works well now so why change it.

Here is a link to the HiMax. and you can download the free plans to look them over for the struts and wings.
My Hi-Max weighs 332 lbs.
https://www.teammini-max.com/aircraft/1700r-hi-max/

[totoro001]

Steve: Thanks I'll check that out!

Joe: Thanks for the info on the wings!  The HiMax is SUPER high on my list of small planes I want to build.  I'm really debating whether the LE XL or the HiMax is the way to go, but it seems to be 6 of one half a dozen of the other.  Just weighing my options

[scottiniowa]

  The HiMax is SUPER high on my list of small planes I want to build.  I'm really debating whether the LE XL or the HiMax is the way to go, but it seems to be 6 of one half a dozen of the other.  Just weighing my options

Totoro001, I assume you have done the pro/con sheet of the two.   I find these two a bit different on mission/weight, but maybe they are closer than I think.  I would suspect the largest is simply - built to plans- one makes weight, one does not...  What other things do you have?  Curious..

[stevejahr]

 The HiMax is SUPER high on my list of small planes I want to build.  I'm really debating whether the LE XL or the HiMax is the way to go, but it seems to be 6 of one half a dozen of the other.  Just weighing my options

Totoro001, I assume you have done the pro/con sheet of the two.   I find these two a bit different on mission/weight, but maybe they are closer than I think.  I would suspect the largest is simply - built to plans- one makes weight, one does not...  What other things do you have?  Curious..

Not quite as simple as saying one will hit Part 103 weight and one won't...

As Team points out themselves, the Hi-Max is really a high-wing conversion of their mid-wing Mini-Max.  And of course there are a range of Mini-Max models going from Part 103 single cylinder engine up to full VW powered.  So hitting Part 103 will depend on what you choose as a starting point (and option choices) in a Mini/Hi Max.

And being built more of variable materials (ie: wood) it is also likely that even the same model of Mini-Max will vary from specimen to specimen (like really any home built).  So careful construction will be required by any to legally hit Part 103 weight.

Add a bit of extra glue or denser wood... or a bit more weld filler... and either a LE or Hi-Max could bust the limit.

My original thought to the OP was perhaps the Cabin Eagle (aka: CE) would be a better match.  But heck a Hi-Max is pretty cool too.

The main key to Vne is the point when aerodynamic flutter commences in any part of the structure.  As the speed increases so to does the potential for flexible structures to begin flutter.  Not to discount the buddy of Vne which is Va whose main key is having the wing stall before it generates more lift force than the structure can handle.  Both of these are really handled the same way: throttle back.

[totoro001]

Hey All!  Thank you for your replies.

ScottInIowa - I have and it's a really tough choice.  This will be the first aircraft I build (I'm certain not the last as I love building about anything), and I know it's important to choose the right tool for the job (or in this case the right aircraft for the mission).  I'm running into a lot of "6 of one, half a dozen of the other".  At the end of the day the HiMax wins when it comes to speed, but the LE XL wins when it comes to simplicity.  It's a tough choice is all.

SteveJahr - I really like the DE or CE, but when we start getting into 2 seat aircraft, now that opens up a whole new world of possibilities.  It just comes down to the fact that there are too many good aircraft choices (not the worst problem to have).

Perhaps the best question for me to ask would be, has anyone ever fully covered their LE/LE XL, and what kind of performance numbers did you see?  I don't want to go about re-engineering anything as I am not qualified to do so, but if someone has covered and potentially added cloth doors, I'd be curious as to see the difference in performance.

Thanks for your help so far!

[Larry H]

Hello totoro,
I'm thinking of doing similar to what you propose. Build it the way you want, make sure you know what you are doing. Keep in mind that in a powered airplane the throttle or airframe drag determines the maximum speed of an aircraft. If you need to throttle back to maintain 63 mph then throttle back. I'm not sure who is going to monitor your speed but fly at 63 if you wish. If I were flying in a direction where I had a 20 mph tailwind or more, I doubt I would attempt to maintain a 63mph ground speed if my tailwinds needed me to get there faster! 😜

Larry

[SGFoster]

I realize I am about to revive this discussion; but, I thought it might be important to note that Vne is 90% of Vd which is maximum design dive speed. Speeds above Vd may result in damage due to structural failure or flutter.

[Aaron]

My personal opinion, unless you plan on dive bombing aircraft carriers, I think the LE is a little too simple and geometric in nature to be slippery enough to be concerned over Vne speeds. Nose dives or flying in a manner where you would be trying to overstress the airplane (not really what the LE is for) are another conversation, but for regular ultralight or light sport style flying, I can't imagine you would be anywhere near those types of speeds. The LE has an awfully dirty cross section begging for drag. Maybe...maybe you might be able to convince me if you close off the fuselage and put some fairings in there to streamline aft of the cabin, streamlined the gear, tail brace wires, cowled the engine in, wheel pants, rounded windscreen, ran internal ailron cables.... I think you are getting my point :p, and at that rate you might be looking at something that looks like a scaled down cub, n3 pup maybe? :p

I could be wrong, but if it were me I wouldn't worry, I've never heard anyone say my airplane is too slippery!

[kalazzerx]

Build a cabin eagle if you want an enclosed cabin anyway and do not care about needing an N number.