Rick,

That is a nice straightforward distribution of material; if it has
enough material at the root it should work great.

Optimizing the distribution of material by trying to keep the stress
in it fairly constant generally leads to dropping the rods out fairly
quickly at the root, so you might have one full span, one half, one
quarter, and one eighth. That is the most efficient use of the
material, but results in a deflection curve with more bend in the
outboard portion.

Dropping the rods out linearly as you have done results in the rods
being more lightly stressed in the outboard portion, but yields a
deflection curve that is nice and even down the wing.

Thanks, Bob K.

> One full span, one 3/4, on half, one a quarter
>
>
>
> ________________________________
> From: Michael McKeown <This email address is being protected from spambots. You need JavaScript enabled to view it.>
> To: This email address is being protected from spambots. You need JavaScript enabled to view it.
> Sent: Wednesday, October 24, 2012 9:42 PM
> Subject: [Ultralight_Soaring] Re: carbon leading edges
>
>
> Are they all full span?
> Michael
> On Oct 24, 2012, at 3:57 PM, ekolbs wrote:
>
>> I'm assuming we are all (Rick and Bob) talking about the 0.092" X
>> 0.22" rods(?). Thanks
>>
>> --- In mailto:Ultralight_Soaring%40yahoogroups.com, Rick Mullins
>> <flyndude@...> wrote:
>>>
>>> I probably should clarify what I said. I have 4 carbon rods in
>>> both the top and bottom cap strips, for a total of 8 per spar
>>>
>>>
>>>
>>> ________________________________
>>>
>>>
>>>
>>> --- In mailto:Ultralight_Soaring%40yahoogroups.com, Rick Mullins
>>> <flyndude@> wrote:
>>> >
>>> > You've got that right. When doing the calculations it quickly
>>> becomes obvious how the wing thickness has a huge bearing on the
>>> number of rods required. I read somewhere one of the main reasons
>>> for the thick wing on the Carbon Dragon was so the wings could be
>>> built light weight enough to foot launch.
>>> >
>>> >
>>> >
>>> > ________________________________
>>> > From: Bob Kuykendall <bob@>
>>> > To: mailto:Ultralight_Soaring%40yahoogroups.com; Rick Mullins
>>> > Cc: "mailto:Ultralight_Soaring%40yahoogroups.com"
>>> <mailto:Ultralight_Soaring%40yahoogroups.com>
>>> > Sent: Wednesday, October 24, 2012 3:03 PM
>>> > Subject: Re: [Ultralight_Soaring] Re: carbon leading edges
>>> >
>>> > That so few Graphlite strips were needed is a testament to the
>>> incredible strength of this material, and to the huge contribution
>>> of having such a thick wing. Bending stiffness scales with the
>>> cube of the depth, so a little extra depth adds a lot of stiffness.
>>> >
>>> > The 15m wing for my HP-24 sailplane design has 28 strips at the
>>> root, and it deflected 47" at 4.4g:
>>> >
>>> > hpaircraft.com/hp-24/update_10_dec_11.htm
>>> >
>>> > Of course, its wing is less than 5" deep at its thickest point,
>>> and it has a gross weight of around 825 lbs.
>>> >
>>> > Thanks, Bob K.
>>> >
>>> >
>>> > > I built the leading edges using two layers of 284 carbon
>>> twill fabric 5.7 oz, laid up at 45 degrees.I didn't vacuum bag.
>>> Using Jim Marske's book I calculated that only 3 rods were
>>> required for the caps but I added another in case I decide to
>>> add some power down the road. I think the prototype deflected
>>> over 20 inches during the load test. Mine deflected a little
>>> over 14 inches.
>>> > >
>>> > >
>>> > >
>>> > > ________________________________
>>> > > From: ekolbs <ekolbs@>
>>> > > To: mailto:Ultralight_Soaring%40yahoogroups.com
>>> > > Sent: Tuesday, October 23, 2012 11:17 PM
>>> > > Subject: [Ultralight_Soaring] Re: carbon dragon
>>> > >
>>> > > Â
>>> > > Rick, thanks for sharing, we all appreciate it. I am curious
>>> what you used for the D cell skin, what type of cloth,
>>> weight/oz, how many layers, did you vacuum bag etc. I am really
>>> surprised that 4Â carbon rods can cary that load with that span
>>> with so (relatively)Â little deflection. I guess I have been way
>>> over designing my spar caps. Any other design specifics would
>>> be appreciated by the group from someone that has actually
>>> built (not just on paper). So thanks again!
>>> > > Mark
>>> > >
>>> > > --- In mailto:Ultralight_Soaring%40yahoogroups.com, Rick
>>> Mullins <flyndude@> wrote:
>>> > >>
>>> > >> I did the wing load test over the weekend. I loaded almost
>>> 1500 lbs on the wings which is the equivalent of 6Gs. Everything
>>> returned to normal after the load was removed. I was expecting
>>> some ugly noises during the test but other than "bonks" when the
>>> leading edge oil-canned, and a crap-the-pants "bang" when a
>>> screw in the test fixture sheared it was thankfully quiet and
>>> uneventful.
>>> > >> Ã?Â
>>> > >> I uploaded a couple of pictures of the test.
>>> > >>
>>> > >> Ã?Â
>>> > >>
>>> > >> ________________________________
>>> > >> From: ekolbs <ekolbs@>
>>> > >> To: mailto:Ultralight_Soaring%40yahoogroups.com
>>> > >> Sent: Monday, September 10, 2012 10:35 PM
>>> > >> Subject: [Ultralight_Soaring] Re: carbon dragon
>>> > >>
>>> > >>
>>> > >> Ã?Â
>>> > >> Any updates? Really interested to hear about results of
>>> load testing. Thanks in advance!
>>> > >>
>>> > >> --- In mailto:Ultralight_Soaring%40yahoogroups.com,
>>> "ekolbs"Â <ekolbs@> wrote:
>>> > >> >
>>> > >> > Wow, very impressive. I just had to reply quickly and say
>>> looks great and thanks for promptly sharing! I'm anxious to
>>> follow you progress. Mark
>>> > >> >
>>> > >> > --- In mailto:Ultralight_Soaring%40yahoogroups.com, Rick
>>> Mullins <flyndude@> wrote:
>>> > >> > >
>>> > >> > > I created a new folder called Carbon Dragon and uploaded
>>> some pictures of build my spar, wing, and a current photo of the
>>> project
>>> > >> > >
>>> > >> > >
>>> > >> > > ________________________________
>>> > >> > > From: ekolbs <ekolbs@>
>>> > >> > > To: mailto:Ultralight_Soaring%40yahoogroups.com
>>> > >> > > Sent: Tuesday, May 29, 2012 6:24 PM
>>> > >> > > Subject: [Ultralight_Soaring] Re: carbon dragon
>>> > >> > >
>>> > >> > >
>>> > >> > > Ã??Ã?Â
>>> > >> > > Sounds great Rick. Any more details and pictures you
>>> could post to the photos section would be appreciated by many.
>>> > >> > > Mark
>>> > >> > >
>>> > >> > > --- In mailto:Ultralight_Soaring%40yahoogroups.com,
>>> Rick Mullins <flyndude@> wrote:
>>> > >> > > >
>>> > >> > > > Yes, you use the carbon rods in the spar caps rather
>>> than carbon tows the plans call for. The shear web
>>> is�?â??�?� 7725 fiberglass cloth like the Monarch.
>>> > >> > > >
>>> > >> > > > Jim's composites manual is great. Lots of good information.
>>> > >> > > >
>>> > >> > > >
>>> > >> > > > ________________________________
>>> > >> > > > From: Michael McKeown <michael@>
>>> > >> > > > To: mailto:Ultralight_Soaring%40yahoogroups.com
>>> > >> > > > Sent: Tuesday, May 22, 2012 11:57 AM
>>> > >> > > > Subject: Re: [Ultralight_Soaring] Re: carbon dragon
>>> > >> > > >
>>> > >> > > >
>>> > >> > > > Ã??â??Ã??Ã?Â
>>> > >> > > > Do the varying length carbon rods make up the spar
>>> caps? Ã??â??Ã??Ã? Ã??â??Ã??Ã?Â
>>> > >> > > > What is the shear web?
>>> > >> > > > I have just ordered the book.
>>> > >> > > > Michael
>>> > >> > > >
>>> > >> > > >
>>> > >> > > >
>>> > >> > > > On May 22, 2012, at 5:21 AM, Rick Mullins wrote:
>>> > >> > > >
>>> > >> > > > Ã??â??Ã??Ã?Â
>>> > >> > > > >
>>> > >> > > > >
>>> > >> > > > >My spar is almost an exact copy of the one Jim uses in
>>> his Monarch. I used 4 of the .092x.220 carbon rods and divided my
>>> spar into quarters. First rod full length, second 3/4, 3rd half
>>> way, etc. I used the same number for both the top and bottom spar
>>> caps for ease of construction.�?â??�?� I made carbon
>>> bars�?â??�?� from about 35 layers of carbon cloth for the
>>> wing connectors. According to Jims composite design book I only
>>> needed about 18 layers to prevent tear out but 35 gave me the same
>>> thickness as the 4 stacked carbon rods, and I would have the
>>> maximum surface area when I glued it up for the load transfer. The
>>> wings connectors are the same as in the plans. I have plenty of
>>> pictures if you are interested.
>>> > >> > > > >Ã??â??Ã??Ã?Â
>>> > >> > > > >I'm about 90% finished. All the major pieces are built
>>> and I'm assembling them now. I am currently fitting the wings and
>>> yesterday �?â??�?� I think I ran into another discrepancy in
>>> the plans. Jim apparently started with a 16 inch wide pod and
>>> later went to 17.and not all the dimensions on the drawings are
>>> consistent. The fittings on my pod are spaced too far apart to
>>> mate properly with the wing fittings. It will be a couple more
>>> days before it has wings now.
>>> > >> > > > >
>>> > >> > > > >From: ekolbs <ekolbs@>
>>> > >> > > > >To: mailto:Ultralight_Soaring%40yahoogroups.com
>>> > >> > > > >Sent: Monday, May 21, 2012 10:04 PM
>>> > >> > > > >Subject: [Ultralight_Soaring] Re: newbie
>>> > >> > > > >
>>> > >> > > > >
>>> > >> > > > >Ã??â??Ã??Ã?Â
>>> > >> > > > >Rick,
>>> > >> > > > >I too have CD plans and have long thought that the
>>> Marske spar would be perfect. Would you share any details about
>>> the spar geometry? How many of what size rods and how do taper
>>> the number down as you progress outboard. How are you making you
>>> center attachment, overlap or fittings with bolt top and
>>> bottom, as in Jim's workshop manual? Really interested to hear
>>> from someone who has actually built, not just on paper.
>>> > >> > > > >Thanks,
>>> > >> > > > >Mark
>>> > >> > > > >
>>> > >> > > > >--- In mailto:Ultralight_Soaring%40yahoogroups.com,
>>> Rick Mullins <flyndude@> wrote:
>>> > >> > > > >>
>>> > >> > > > >> Welcome Claude.
>>> > >> > > > >> I'm building a Carbon Dragon and I used Jim Marske's
>>> spar design in it. Simple, lightweight, and strong. Doesn't get
>>> any better than that.
>>> > >> > > > >>
>>> > >> > > > >>
>>> > >> > > > >> ________________________________
>>> > >> > > > >> From: claude
>>> > >> > > > <claudebouzerand@>
>>> > >> > > > >> To: mailto:Ultralight_Soaring%40yahoogroups.com
>>> > >> > > > >> Sent: Monday, May 21, 2012 11:59 AM
>>> > >> > > > >> Subject: [Ultralight_Soaring] newbie
>>> > >> > > > >>
>>> > >> > > > >>
>>> > >> > > > >> Ã??Ã?'Ã?¢â?¬Ã?¡Ã??â??Ã??Ã?Â
>>> > >> > > > >> Hi all,
>>> > >> > > > >>
>>> > >> > > > >> I am living in France and I plan to build a Mitchell
>>> wing B10 (I have the plans) I had a Bright Star Swift SN 16 I
>>> sold 1Â year ago because I hadn't place anough to store it and it
>>> was not easy to foot lauch(too heavy) .I am aeronautical
>>> technician .I just want to use Jim Marske method for the spar-I
>>> am waiting for his book I ordered last week.Your group could
>>> provide me good ideas to perform this project!
>>> > >> > > > >>
>>> > >> > > > >> Regards
>>> > >> > > > >>
>>> > >> > > > >> Claude