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Questions about building a Q-200

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12 years 2 weeks ago #1246 by patchntx
I want to build my own aircraft. I have narrowed my interests to the LEZ and the Q-200. I am leaning towards the Q-200. I have read almost all the articles here and have a few questions. The most foremost question is about materials and parts. It seems that current owners and builders have created a fairly comprehensive list of do's and don'ts in addition to good upgrades in construction and equipment. Outside of incorporating all this knowledge into a new aircraft, has anyone tried improving the wings with modern materials? I am not looking to reinvent this bird or even deviate from plans and suggested modifications by flying builders, but using modern alternatives for foam cores, modern hi- temp epoxy, and alternative fibers like Pre-preg CF or Aramid? What concerns me the most is the old convention that quickies should be painted white or light colors because when the wings get too hot they get soft? This really seems like something that should be addressed in a new bird. Are better foams available? What about multi-cure epoxies that 1st cure around 100F and second cure around 250F? Wouldn't those be a lot better than using epoxies that get soft in the sun? How about straight substitution of pre-peg CF in some or all of the layers of laminates? I am also curious about the possibility of using RV-4 style main gear legs as opposed the the hoops,stubbies, or wing-tip gear?

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12 years 2 weeks ago #1249 by admin
Hi Patch,
Welcome. Using new epoxies and foam, actually are fairly large design deviations and they should be approached with caution.

I have heard several people talk about using Carbon Fiber exclusively to build their Q's, but I'm not aware of any that are flying.

The problem as I see it, is that one deviation from the plans, leads to others, and before you know it, you're pretty far down the rabbit hole, chasing a problem that didn't really exist in the first place.

"Getting Soft" isn't really the reason that the planes need to be painted white. It has to do more with delamination of the glass structure from the foam. This in turn causes structural weakness.

Richard from FLAPS is bringing back a lot of the original kit parts and should have full kits available in the near future. These will include several options not available on the original kits, including the RV-4 style gear you referred to.

Not sure if any of this was the answer you were looking for. Please let me know. I appreciate your time, support, and enthusiasm.

Warm regards,
Dan Yager
QBA Editor
www.quickheads.com

Flying an aeroplane with only a single propeller to keep you in the air. Can you imagine that?

— Captain Picard, from 'Star Trek: The Next Generation' episode 'Booby Trap.'

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12 years 2 weeks ago - 12 years 2 weeks ago #1251 by patchntx
I am almost neurotic about safety and reliability. I am really on looking at proven improvements. I have read a couple of articles about wings softening and I think there is mention in the plans on the page with the paint recommendations. I have also read about the delamination issue. The EAA has published 2 articles on using epoxies that allow for a post-cure. They also teach it in their seminars. I can't see why anyone would want to do an entire airplane in CF. I don't see a need to do the fuselage in CF unless it was for a safety tub around the cockpit for crash protection. Also, CF is still pretty expensive. Doing the wings in CF alone could cost thousands just for the fabric. But why does anyone "want" anything? My interests lie with safety, durability, and longevity. Too many stories about this or that part breaking or cracking. I would only be interested in a stronger epoxy or enough CF in the wings to increase safety margins, Vne, and durability. (Vne assuming structural integrity is the limiting factor and not control surface flutter.) I am not interested in deviating from plans to use some weird engine I like or to go faster, or higher or some other performance increase. Just better materials. Of course, like any other builder, I will do what I do. I just want to know if anyone has experimented with other materials in the wings with any better success. By the way, I am glad someone was able to give support and even bring back kits for these great birds.
Last edit: 12 years 2 weeks ago by patchntx. Reason: spelling

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12 years 1 week ago #1254 by mylittlemgb@yahoo.com
First, a little history. When Burt Rutan designed the moldless construction method, he was working with available materials and developing a new technique for homebuilders. He used foam developed for floating boat docks. It was stable, light weight and could be cut with a hot wire to make wing and fuselage shapes. A few attempts have been made to improve on the process over the decades. Perfecting those techniques Burt had started can result in very good aircraft. Dave Ronenburg did so on the Berkut and produced very good wings by adding a few modern materials and techniques. Making the foam as close to perfect before doing the lamination, using best practices and current materials, then vacuum bagging at 10" insted of 28" vacuum to prevent crushing the foam results in wings that were very strong, light and straight. An attempt was later made to produce molded hollow wings. The improvements were obvious in outside surface finish, but the cost went way up and the weight was the same.


Making one set of wings using prepreg fabrics would be cost prohibitive as you would need hard molds and an autoclave to cure the parts in. Adopting the best current fabrics and epoxies will result in very good products that we can afford.


The whole paint it white thing is way overblown. The temperature at which plastic materials start to soften is called transition of glass temperature.
(helpfull definition here faculty.uscupstate.edu/llever/Polymer%20...urces/GlassTrans.htm)

The point Dow floatation foam starts to soften (165 F) is higher than planes get to in the sun. The same is true for epoxies available today. Even Burt's brother defied the white rule and painted his plane light blue! It is true that glider techs could change the twist of a wing by painting it black with watercolors, getting it as hot as possible and appling a force to the end if the wing for a day or so. That is a long way from structural failure because you painted your plane red or purple. So bottom line is the problem was never as big as some made it seem. There are no examples of accidents resulting from painting a plane a darker color.

www.tom-morrow-land.com/tests/cartemp/index.htm

So can we improve on the way Quickies and LongEzs were made? Absolutely. But as noted, we want to improve on , not redesign the product. So selection of materials and refinement of processes will result in improvements. The improvements will be more in the area of ease of construction. We will all get better planes faster, with more consistent results.

As for the landing gear we have already made that change and have done the testing. The gear is a Wittman design like the RV gear and we did not loose any performance, but it did make the plane easier to land and takeoff. The new kits coming will not offer the old style gear. After dealing with the FAA the past 6 months they have determined the old style gear to be the biggest hazard for the plane and first flight accedents. Todate they have blessed all the safety improvements we have made as wwell as our goal to make the 51% rule and keep the build time at or below 500 hrs.


Thank you,

Richard Kaczmarek
F.L.A.Ps LLC

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