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RE: Carbon Dragon stuff 11 Dec 2013 23:30 #679

Hi Phil,
I have one other suggestion for you to consider.

You should be spending some time learning about making the parts for your Dragon by vacuum infusion. This was the only way I determined that I could safely and correctly build the strongest and lightest parts for this airplane. Trying to do any other kind of layup takes a lot of people and in an effort to keep within the time restraints of the resin, speed causes the use of excess materials and poor fabrication.
I didn't not get to the point of determining what resin to use in the fusion process, but I am sure with all of the high performance planes being built today someone has one that fits the bill.

There is a fellow in France that is building a 39' Cruising Multi Hull sail boat. He had laid up and infused everything so in his build all by himself with total success. I believe the largest part was 39' long with a 6 or 8'beam and a depth of somewhere around 6'.He sells a practice kit and a DVD that takes you thru the entire process for about $ 100.00 as a way to defray some of the costs of his build and in the interest of assisting others that need to layup large light strong parts without the assistance of an army of workers. Some of Marske's parts required as many as 16 people working at break neck speed to complete the lay up and bagging before the resin kicked, and he admits that the parts could have been made a lot lighter if he was able to use a commercial type of fabrication process.

My plans are not for sale. I guess I am a collector of sorts and I have a great fondness for this airplane. I built a CNC router with the intent of using it to cut all the parts that I would need to build this airplane. I am still considering completing at least that part of my construction schedule some day. It might be a great part time business . I built the router after discovering that a lot of the parts in the drawings were done poorly and needed to be redrawn . After a while I concluded that the I could redraw the parts and accurately cut them on a CNC router faster than cutting and finishing them by hand.

Hope this has helped you out a little . If you have any further thoughts or questions that I may be able to shed some light on, please don't hesitate to call me.

Good Luck

Wally

P.S. Steve Arndt told me once that he thought that the Dragon built to plans but with stronger materials would still be a blast to fly and unless you were an expert pilot you wouldn't notice any performance differences. He also said his heavier dragon was a lot faster than plans built Dragons and that he could still find a lot of micro lifts to fly in. He also said the extra speed helped him get from one thermal to another which he felt was really important.




From: 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.
Subject: RE: Carbon Dragon stuff
Date: Thu, 8 Sep 2011 10:57:39 +0100


Hi Walter,

Thanks for that - it's pretty much what I gleaned from Jim's composite manual, and why I am looking to use Aeropoxy which has a glass transition temperature (Tg) of 194F with the slowest hardener that I'm considering using. While I don't think that high skin temperatures are going to be a big problem here in Ireland (blazing sunshine is something of a novelty here!) it's a very different story in the French Alps where I would like to fly the Carbon Dragon. From experience up on the mountain launch sites the black carbon fibre cross booms inside hangglider sails regularly get almost too hot to touch. I've never actually measured the temperature but having learned a little about epoxy Tg temps etc, I'm beginning to wonder if we're not sometimes pushing our luck.

I'm currently working my way through Jim's manual and re-calculating the loads on the CD wing so that I can completely eliminate all the spruce and ply parts and build purely out of carbon fibre. I'm no where near beginning construction yet but will hopefully have a number of test pieces finished and load tested to destruction before Christmas. Based on those test results I'll then start re-working the design for all carbon construction. I've posted copies of my work so far in the files section of the Carbon Dragon Builders Yahoo group and I'll continue to post up further calculations and test data as I develop them. Don't treat my calculations as either definative or correct - they are my first attempt at this sort of thing and need to be double and tripple checked!

I am working off a set of copies of the CD plans but would be interested to know how much you might be willing to part with your original plans and manual for. The copied plans that I have appear to have scaling errors of up to 1% on different drawings - something I can easily compensate for but an inconvenience.

Interestingly, in chatting to Jim Marske (by email) I discovered that he married a girl from a town just up the road from me! With a little luck I might be able to entice him to visit me next time he's in Ireland.

All the best,

Phil.



From: Wally L [This email address is being protected from spambots. You need JavaScript enabled to view it.]
Sent: 08 September 2011 04:21
To: This email address is being protected from spambots. You need JavaScript enabled to view it.
Subject: Carbon Dragon stuff


Hi Phil,

I attended a Marske seminar 3 years ago. West System resin was mentioned and we were told that it shouldn't be used in aircraft construction. Jim said its post cure temperatures were too low to create a safe airplane. If I remember correctly, he said that West System could safely be cured at about 100 to 110 degrees F. An airplane left in the sun can easily reach temps of 120 to 130 Degrees F. His recommended epoxies post cure in the 150 to 175 degree range which is what he recommends.

Give him a call and ask him about post curing WEST System resins, it could save your life.

I live in New Hampshire. I have a set of Carbon Dagon plans and sported the idea of building one for over 10 years before I decided not to build one.

Good Luck.

Walter Luikey

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