Carlson Struts

[Poorman2]

I am getting ready to order my strut material. On page 57 of my plans, it calls for aproximately 78 3/4 inches. On Carlsons web site it shows the small struts being 126"s long. Before I call them, I wanted to ask how are most eaglers ordering theres? Also it shows streamlined jury strut material. I know Sam Bucannan used round tubing. Is there any advantage to using the streamelined jury struts ? Are they too heavy to use on the LEXL? Also what about there Jury strut instalation kit? I will also need strut attach material. I would think the 3/4 x 3/4 x .o65 square 4130 would be stronger and lighter than the solid 6061t6. What say yee? Thanks Randy.

[Justin]

Unidirectional carbon fiber tube. Its incredibly lighter and stronger than 4130. I'm trying to talk myself out of building the fuselage out of it, hopefully someone here will put me in my place...

[rockiedog2]

Hi Poorman
I'm not sure I understand what you're proposing but sounds like you're talking about building up a tubular fuse with CF tube bonded together. If that's right well, naw ain't no way I'd do that man. Here's why

Murray and I kicked around building up a tube gear outa CF from these folks
http://www.dragonplate.com/
notice they don't rate the compression strength only tensile. I  called and asked them and they said they didnt know. So I bt a 2"x2"x6' thickwall square tube and tested it. Fixed the ends and put a jack on a scale under it in the middle and the side under compression failed at 200#.. Buckled.

Not being an engineer type I'm not sure if all that  would qualify as a valid test or not but it's all I needed. There's a lotta tubes under compression in our fuses.

 But maybe I don't understand...

[Poorman2]

Naw Joe, I was just asking about the streamlined Carlson struts for the wings that Leonard used on his prototype LE XL. I didn't get an answer yesterday so I just ordered them cut at 80 inches long and ordered the streamlined jury struts along with the mounting kit. I just hope they are not too heavy compared to the round tube. I called Frank Johnson yesterday about building my prop. He said it may be May or June before I get it. He is like Scott Casler, covered up with work.

[Sam Buchanan]

Naw Joe, I was just asking about the streamlined Carlson struts for the wings that Leonard used on his prototype LE XL. I didn't get an answer yesterday so I just ordered them cut at 80 inches long and ordered the streamlined jury struts along with the mounting kit. I just hope they are not too heavy compared to the round tube. I called Frank Johnson yesterday about building my prop. He said it may be May or June before I get it. He is like Scott Casler, covered up with work.

I know you have already placed your order for the streamlined jury struts but here are some numbers:

Sixteen feet of 6061 1/2" x 0.035" tubing = ~1 lb.  (0.061 lb/ft)

Sixteen feet of streamline tubing = ~3.5 lbs.   (0.228 lb/ft)

The streamline stuff is much heavier than tubing.

[Poorman2]

Thanks Sam. Thats what I figured, but I decided to order them any way. I can always use them on another project. Tell Doug thank you for me for the kit.

[rockiedog2]

Naw Joe, I was just asking about the streamlined Carlson struts for the wings that Leonard used on his prototype LE XL. I didn't get an answer yesterday so I just ordered them cut at 80 inches long and ordered the streamlined jury struts along with the mounting kit. I just hope they are not too heavy compared to the round tube. I called Frank Johnson yesterday about building my prop. He said it may be May or June before I get it. He is like Scott Casler, covered up with work.

oh yeah I should have said Justin. He was the one talking CF
where do you live Poorman. I think I saw Flora?

[Sparetime]

Old school video. Round tube drag.


I apologize for not knowing how to simply attach a URL. This site makes it very difficult. Must be keeping many from posting. It should be able to handle a simple paste.

[font='Segoe UI', 'Helvetica Neue', 'Liberation Sans', 'Nimbus Sans L', Arial, sans-serif]http://www.youtube.com/watch?v=ftq8jTQ8ANE&feature=youtube_gdata_player[/font]

[font='Segoe UI', 'Helvetica Neue', 'Liberation Sans', 'Nimbus Sans L', Arial, sans-serif]Jim[/font]

[Dan_]

This site makes it very difficult. Must be keeping many from posting. It should be able to handle a simple paste.  

Jim,
Usually the problem is the OP does not put the URL on a separate clean line.  This time I dunno, looks like you may have tried to use the insert hyperlink button, as all the formatting codes are showing in your msg.

For YouTube, Vimeo, and just about any popular video upload site URLs, you don't "attach" them in your posts on this forum -- all you need do is paste the URL on its own clear separate line, like I have done here by highlighting your URL from your msg, hitting "copy" from the edit menu on my browser and pasting in this msg below.  

Keep hacking away at it...

P.S. hit the "Preview" button at the lower right while you are working on your post,  videos or attached pics should show.

http://www.youtube.com/watch?v=ftq8jTQ8ANE&feature=youtube_gdata_player

[Sam Buchanan]

Old school video. Round tube drag.

[font='Segoe UI', 'Helvetica Neue', 'Liberation Sans', 'Nimbus Sans L', Arial, sans-serif]Jim[/font]

Yep, the Eaglers gave that vid a good critiquing a couple years ago.

There is no doubt round tubing is draggier than streamline tubing. But if you want to stay within Part 103, you don't have any choice...the streamline stuff is just too heavy for any but the most fanatical builders. And at Eagle speeds (way less than 210mph!!), I'm not sure how much the drag of round tubing degrades performance.

[Sparetime]

Sam, I  notice Carlson struts on xl-58. Would you use tube next time? 
I agree at eagle speeds drag isn't as much of a factor, so maybe the boss can enlighten us as to why the choice of Carlson?


Jim

[rockiedog2]

Sam, I  notice Carlson struts on xl-58. Would you use tube next time?
I agree at eagle speeds drag isn't as much of a factor, so maybe the boss can enlighten us as to why the choice of Carlson?


Jim

no doubt we're slow enough that drag is lessened but we're also low powered and dont have much thrust left over to climb with. the drag of those round struts cuts way into the climb and also makes the sink significantly higher. ive flown mine with round struts and then with streamlined cuffs and the streamlined struts are definitely worth it. when considering our climb rates a little extra drag is a lot
Joe

[Sam Buchanan]

Sam, I  notice Carlson struts on xl-58. Would you use tube next time?
I agree at eagle speeds drag isn't as much of a factor, so maybe the boss can enlighten us as to why the choice of Carlson?


Jim

I would stay with the Carlson struts. The cost isn't very much more and I much prefer the attachment method for the Carlsons to the welded fittings for the round tubes. And any reduction of drag is a good thing.

Initially Leonard used Carlson struts because he felt the added stiffness wouldn't require jury struts. He has since backed off that position and now recommends jury struts on all his planes.

[Dan_]

These lift struts are streamlined using big box store rolls of aluminum flashing material .016...  Comment by the "inventer" Scott Ehni below after pics...

Yep, that's a turbine on the nose...









Comment by Scott Ehni on March 7, 2012 at 7:53am  
The fairings are fabricated from a flat piece of .016 6061 T6 aluminum. After we punch the holes you use a large round die to form the two short edges to the radius of the strut tube then you use a knife edge die to form the first two returns and last you bend it on the center-line to make the final shape. The last bend is left open slightly so when you put the farings on the tube it has a more aerodynamic shape.
Scott

[Theodore]

These lift struts are streamlined using big box store rolls of aluminum flashing material .016...  Comment by the "inventer" Scott Ehni below after pics...

Yep, that's a turbine on the nose...









Comment by Scott Ehni on March 7, 2012 at 7:53am 
The fairings are fabricated from a flat piece of .016 6061 T6 aluminum. After we punch the holes you use a large round die to form the two short edges to the radius of the strut tube then you use a knife edge die to form the first two returns and last you bend it on the center-line to make the final shape. The last bend is left open slightly so when you put the farings on the tube it has a more aerodynamic shape.
Scott

Please more on this! Thank you
Theo