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Progress on Phil Lardner's All-carbon CD? (Part 1) 02 Jun 2015 07:27 #892

Hi Phil, congratulation ! Very nice.
I have some questions about your horizontal tail.
Do you have front spar ? ( It seems to be impossible to assemble the front spar and ribs on original plans ! )
How do make the rear spar ? ( you said the skin is structural !? )
How do you attach your tail with the boom ? ( like originals plans ? )
How do you make the hinge ? ( carbon too ? )

Sorry for so much questions, Bertrand. :woohoo:
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Progress on Phil Lardner's All-carbon CD? (Part 1) 02 Jun 2015 11:29 #893

Hi Bertrand,

I've been too busy beavering away to upload my latest photos... so I'm doing that right now - 171 new pics to pour over! They'll take an hour or so to upload, but you'll find them here, eventually: www.ihpa.ie/carbon-dragon/index.php/cd-b...hil-lardner-s-cd#new

Horizontal Stabiliser Front Spar:
You're right - you can't build the H-stab in carbon as you would in wood, and I had to have a good think about it before I tackled that problem. My solution was to fabricate the front spar in one piece on an A-shaped mold (rather than the gentle curved shape of the original wooden spar) with a single carbon rod in each of the four spar caps. You can see the 'A-shaped' mold I used to shape the front spar in the photos below.

I then cut the H-stab ribs at the correct angle to allow the front spar to be bonded to the cut ribs. The 'nose' sections of the ribs were then bonded onto the spar to give the final shape. This worked very well. I also used this method when constructing the vertical tail.

H-Stab Rear Spar:
All my spars are fabricated from two layers of 195gsm carbon twill cloth cut at 45degrees to the long axis, with the carbon rods sandwiched in between the two layers, at the edges of the spar to form the spar caps and flanges. For all but the 'bent' front spar on the H-stab you can use continuous lengths of carbon rod in the spar caps. There is no need to cut them at the center / root. The carbon rod can easily be bent to accommodate the slight bend in the spar caps. I only discovered this after making my first H-stab spar with a double-taper. My elevator spar was made with continuous lengths of rod and turned out perfect!

H-Stab Attachment points:
Like Rick Mullins I used two metal attachment fittings for the rear attachment points and just a single V-shaped fitting for the front mounting. The two rear fittings will slide onto fixed metal pins attached to a horizontal bar fixed to the tail boom (as per the original plans) and the front fitting will be secured by a single, spring-loaded pip-pin to facilitate quick assembly and removal.

I'll show you how I made the carbon hinges in the next post... the system is limiting me to 8 attachments per post!...
Last edit: by Phil Lardner.
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Progress on Phil Lardner's All-carbon CD? (Part 1) 02 Jun 2015 11:38 #894

...continuing on from earlier...

Carbon Hinges:
I tried making the carbon (female) hinges in the manner described in the original plans and builders manual but found the method unsatisfactory... and the results a bit of a disaster if I'm honest!! So I made the female hinges in two parts and bonded them together later. I made one long length of hinge 'stock' and then cut it up to size on my table saw, and shaped the top of the hinges using a bench mounted disc sander. Each half of the female hinge was made from five layers of carbon cloth. The two 'halves' were then glued together and 1" wide reinforcing strips (made up of 17 layers of carbon cloth) were glued either side of the hinge top. The results were excellent!

The male halves of the hinges were made as described in the original plans and builders manual.

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Progress on Phil Lardner's All-carbon CD? (Part 1) 11 Jun 2015 09:53 #896

Someone on Youtube was asking how I'm joining my three wing sections together. I calculated the loads using the method detailed in Jim Marske's Composite Design Manual (available here: www.marskeaircraft.com/ - and worth every penny!) - my calculations can be found here: carbon-dragon.ihpa.ie/index.php/cd-build...ardner-s-cd#analysis.

Please note - the cheap looking gutter bolts you see in the photos below will be replaced with stainless steel AN bolts (6mm dia) and Nylock nuts in the finished wing!

Last edit: by Phil Lardner.
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Progress on Phil Lardner's All-carbon CD? (Part 1) 12 Jun 2015 17:57 #897

Rick, greetings.... I had not looked at this site since heading back to the midwest in late April. I am catching up and enjoying it plenty! I am curious about the drag beam interconnect you mention. I think the beam through the boom is layed in perp to the center line of the boom in my plans but the fittings either side are twisted to present to the wing attach tangs. This seems to work fine on mine all these years but I see no reason to not build it with the through @ the (4 degrees)? and keep the plates flat for ease of construction. Am I making sense?

Also, I could use some new leading edge skins for my wing and wonder if you might be interested in creating some for me? We can talk if you are game to.

Wondering who is the third CD @ Wallabee? Is Steve Arndt still flying MD there. Steve and I took apart the POC with our plans in hand in Hutchinson, KS I think it was in 1995. I have not heard much about him and his MD for at least 8 years now...can you update me please.

Gus Malm Alnair & Realm
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Progress on Phil Lardner's All-carbon CD? (Part 1) 12 Jun 2015 18:35 #898

Yeah, we all owe a BIG thanks to Phil for setting this up and the ongoing efforts to keep it going.

I guess I would have to see how you twisted the mounting plates. They mount with the drag beam sandwiched in between and it doesn't seem like they extend past the beam far enough to twist them the 4 degrees you would need to match up with the rear wing connectors.

I took my leading edge molds to Wallably because Mick was thinking about building another one but has decided against it now. I'll be bringing them back home and you are welcome to use them.

The third CD at Wallaby is mine when I head there in the winter.

Steve has not flown his CD for several years. He built a motorized Silent 2 and is flying that now. He competes a lot and does very well. I think he may have set a FAI distance record with his CD before he quit flying it
Last edit: by Rick Mullins. Reason: spelling
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