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Jun 29, 2004, 05:59 PM
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SuperGee


I want to build a SuperGee.
Any one who has built one or flys one what do you think of it?
Rob
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Jun 29, 2004, 10:34 PM
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Super Gee II


My son and I have built and flown two of these DLG sailplanes.
The plane is an absolute joy to build and fly.


Our first Super Gee II

You will probably find the SG2 a little more challenging to build than other similar designs, but not overwhelmingly so. The main demands of low weight and high strength are achieved through good techniques and use of proper materials.



If a prospective builder starts like we started--without experience in vacuum bagging and molding--then that person should expect to spend some time and money getting a shop set up and becoming practiced in the various techniques and skills.






For some components like the pod, there are many possible techniques to reach the same or nearly the same result. We used a lathe to shape the cylinder for our plug, and then split the 2-piece plug and sanded facets to create the planned shape. Mark had the use of a CNC mill (oooh, lucky guy) to make his mold. Others have used a variety of methods to make the shape and mold their pods.





In Progress
We are continuing work on additional planes to accomplish a few interesting and fun goals:

1) Refine our building techniques to approach as close as possible Mark Drela's expert results.
2) Document online the entire building process.
3) Master and produce any parts that can be economically made and offered to the sailplane community.
4) Encourage by any means the building and flying of advanced designs, including the many aircraft inspired by Dr. Drela's efforts and using his airfoils.
5) Learn to fly these planes at an expert level.

If you ready for a challenge, then welcome aboard! Everyone we know who are building this design, either as a loosely-followed inspiration or as a faithful reproduction, are having fun and enjoying exceptional performance.



Note: At this time, there are easier ways than building an SG2 to experience Mark's concepts and airfoils. Denny Maize's XP-4 and Oleg Golovidov's Taboo XT are beautiful and are great performers. I hear that Maple Leaf Design's Encore is now made using Drela airfoils. There are molded imports that also use similar airfoils. Many of these designs use an expanded planform, increasing wing area to balance higher weights. We think this is a good thing because these airfoils will normally fly better at lower wing loadings.

The SG2 is a great building and flying project. As we make progress with our projects we'll keep everyone posted via the forums and eventually a new web site about building advanced sailplanes.

Aradhana Singh Khalsa
Fateh Singh Khalsa
New Mexico

p.s. For you eagle-eyed viewers, the tip doublers are supposed to be kevlar, with half dollar-sized carbon patches for throwing peg reinforcement. Our first two wings went to IHLGF, where Mark kindly straightened us out.
Last edited by ASK; Sep 14, 2004 at 03:18 PM. Reason: Correction on tip doublers
Jun 29, 2004, 11:25 PM
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ASK, thanks for the encouraging words.
Looks like you guy are allready expert at what you are doing.
I like learning new stuff. When doing a project I like to do as much of the work as I possibly can.
I have had alot of exp. doing hand layups with resin and epoxy ( worked in a boat yard and built a couple of full scale home builts), but I never have seen vacuum bagging done. Should be fun to learn. I finished a foam cutter a while back, so I have one tool allready.
I am looking forward to your future posts.
Thanks, Rob
Last edited by robert harik; Jun 29, 2004 at 11:32 PM.
Jun 29, 2004, 11:41 PM
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Supergee


Aradhana,

Looks like you topped your Bubble Dancer with your Supergee build. Very nice work!!! Did you use Drela's EVO settings for the SG2?

Also, what are the conditions of the forest's there now, in and around Espanola...dangerous I suspect?

Cheers...Rick in Austin
Jun 30, 2004, 12:04 AM
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How much did your SG2's end up weighing?

Greg
Jun 30, 2004, 12:25 AM
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Quote:
Looks like you topped your Bubble Dancer with your Supergee build. Very nice work!!!
Thanks for the compliment! We continue to learn courtesy of everyone's help. Special thanks to Mark and the SALGlider Yahoo Group, Phil and Bill for their vacuum bagging video, and all the builder/pilots of our own Albuquerque Soaring Association.

These SG2s were our first foam and composite planes, and came out quite nice at about 10 oz. each. With a little perseverance and refinements the next couple planes should be in the preferred 8-9 oz. range.

Quote:
Did you use Drela's EVO settings for the SG2?
We first tried using our Eclipse 7, but that radio isn't able to accept (simultaneously) all the specified settings and configuration. We have an EVO 9 and are using Mark's configuration (thanks again, Mark). That's working out well.


Mark showing me how to configure the EVO for the Super Gee II on his backup radio, at IHLGF

Quote:
Also, what are the conditions of the forest's there now, in and around Espanola...dangerous I suspect?
Yup, our local Santa Fe National Forest is closed due to fire danger but we can get to all of our flying sites, and can travel to other areas for hiking and backpacking trips. The AZ/NM/TX annual monsoon season might be kicking in early--we'll see. A good wet monsoon will greatly reduce the risk. We are fairly close to the burned areas from the Los Alamos and other recent Jemez mountain fires.

-Aradhana Singh
Last edited by ASK; Jun 30, 2004 at 12:27 AM.
Jun 30, 2004, 01:20 AM
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While the primary reason I traveled down to the IHLGF this year was to watch the incredible pilots, I also wanted to see a Supergee in action. Most of the current "competitive" dlg designs are at least loosely based on the Supergee, usually with some changes made to make it a little more production friendly. Built per plan, I believe that the Supergee may well be the best DLG design around. As I build my own Supergee (also my first composite glider), I am learning that it will certainly take a bit of practice and refinement of techniques to get the airplane into the weight range that it should be to perform to its fullest potential.

As Aradhana mentioned, it does require an initial investment in supplies and tools, but once you have made the initial purchases, subsequent builds will cost relatively little, with minor replenishment orders scattered here and there.

My own Supergee is making progress. I now have the cores in my possession and have begun sanding the sparcap grooves and shaping the CF sparcaps for the wing. I also have the pod mounted on the boom as well as the stab mount. In the last week, I have received the final pieces for my Vacuum Bagging system and will be doing some testing as the week progresses.

I am very much looking forward to flying it but have been enjoying the building process as well.

Aradhana: Excellent pictures. I am curious, how did you get the illustration/logo onto the wing?
Last edited by briandlg; Jun 30, 2004 at 09:37 AM.
Jun 30, 2004, 10:00 AM
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Hi Brian.
Congrats on your progress!

Quote:
Originally Posted by briandlg
It appears that you are building some additional wings beyond the ones you had in Poway!
That's right. We are making a few extra wings to fulfill requests from friends. We made five of the pre-spar cores at Mark's 48 gram weight, and our two first finished wings (before wiring and servos) are 117 grams and 122 grams. Target weight is 105 grams.



We have a new heavy linoleum edge roller for better rolling flat and drying out of the layup. This tool ($23 at the professional flooring tool supply store) should work better than the 1" wallpaper roller we have using.



At IHLGF, Phil Barnes showed us his personal XP-4 wings made with 1 oz. kevlar. He pointed out how with heavy rolling he was able to spread the kevlar yarns to fill the spaces in the loose fabric. I think it was Mark who said he is using a long handle to more easily put his whole weight into the rolling.

Quote:
How did you get the illustration/logo onto the wing?
Making and laying up the logo is fairly easy, and looks great.
We did our design work in Adobe Illustrator, printed on an inkjet (HP DJ 1700), and wetted into the layup on top of the kevlar.


Lay the logo printed on tissue paper first onto the mylar, then follow with the fabric layers

You can also add your "reward for return" info on the bottom of the wing. We taped a flat piece of tissue paper (like you use for wrapping a gift) onto some inkjet cardstock, set the printer driver to adjust for cardstock, and printed normally. The ink doesn't run at all. YMMV depending on your printer and ink.

-Aradhana Singh
Jun 30, 2004, 10:18 AM
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Those are some great tips, thank you. I believe you mentioned when we spoke in Poway that you were using a Feathercut system and cutting your own cores. How long did it take you to really get the hang of cutting them?
Jun 30, 2004, 11:28 AM
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Quote:
Originally Posted by briandlg
...using a Feathercut system and cutting your own cores. How long did it take you to really get the hang of cutting them?
We started with the Feathercut, as much to learn about foam as anything. We are now working on a CNC system, and have also tried a set of Les Horvath's cores.



It took many viewings of Phil Barne's vacuum bagging video and a lot of practice to get the cutting skill down pat. We threw away over 10 panels while getting the hang of it. We are even able to get fairly good tail cores now, but I don't think you can equal the CNC for thin cuts.

If you are diehard and want to learn about foam like we do, then by all means work with a gravity system and play to your hearts content. If you just need one or two good core sets of an established airfoil/planform, then we'd recommend buying a set from Les.

Tail Core Weights
There is one caveat. We are having trouble with the tail core weights. Both Les' and our tail cores are heavier (about 1 gram each vertical and horizontal) than Mark's, even after sanding. Since 2 grams on the tail requires 8-10 grams on the nose to balance, this is important, especially on a HL glider!

After speaking with a number of folks about this, we have a theory.

We think maybe blue surfboard or "Spyder" foam is heavier than the white stuff that some people have used. If you check pictures of Mark's plane you'll see that the cores are white. We note that cores cut out of Dow Hi-Load 60 and Dow Surfboard foam weigh about the same.

We have a small amount of the white material courtesy of a friend, and are trying to get some material from a surfboard blank manufacturer.

After getting our CNC finished and dialed in, we will test using the "good stuff" and report back--it will be a few weeks.

Aradhana Singh
Last edited by ASK; Jun 30, 2004 at 11:33 AM.
Jun 30, 2004, 12:08 PM
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Quote:
Originally Posted by ASK
We started with the Feathercut, as much to learn about foam as anything. We are now working on a CNC system, and have also tried a set of Les Horvath's cores.
Any good links to info on building your own CNC system for these purposes? I have heard that Les' cores are very good...but at $40 a set, I can't order in the quantity needed to experiment.


Quote:
Originally Posted by ASK
We have a small amount of the white material courtesy of a friend, and are trying to get some material from a surfboard blank manufacturer.

After getting our CNC finished and dialed in, we will test using the "good stuff" and report back--it will be a few weeks.
Please do report back. I'll be very curious to hear how they turn out. I too have been on the hunt for the white foam scrap from surfboard companies...I would imagine I have easier access here in SoCal than you do in NM. I'll let you know if I hit pay dirt.
Jun 30, 2004, 12:21 PM
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Quote:
Originally Posted by ASK
At IHLGF, Phil Barnes showed us his personal XP-4 wings made with 1 oz. kevlar. He pointed out how with heavy rolling he was able to spread the kevlar yarns to fill the spaces in the loose fabric. I think it was Mark who said he is using a long handle to more easily put his whole weight into the rolling.
I just did a layup with 1 oz Kevlar, and noted the following:

1) Hard-rolling of the Kevlar to flatten the fibers must be done after the Kevlar is blotted. Rolling of overly-juicy Kevlar allows the fibers to squirm around too much and deforms the weave.

2) On the other hand, if the kevlar is extremely dry, hard-rolling may pick it up off the mylar in spots. I think the right approach is:
a) blot well with firm rolling over smooth paper towels or toilet paper
b) rolling with just the roller to flatten the fibers
c) blotting again with paper towels for minimal resin content

3) It's essental to have the Mylar resting on a very hard surface when rolling. I had a paper towel sitting under the Mylar, and when the roller passed over it the compliance apparently allowed the Mylar to indent slightly, enough to pull on the fibers and deform the weave.

4) For some reason, sometimes moderate pressure is enough to flatten the fibers, and other times lots of pressure is required. Might be due to different resin content. In any case, start with moderate pressure, and increase only if the fibers refuse to flatten.

5) It's important to fix the roller orientation when making a rolling pass. The long handle helps. If the roller is moved in even a very shallow curve along the kevlar, it will deform the weave.

BTW, in one of the photos you show the wet-out Kevlar over the blue tip paint. That Kevlar looks like it could be blotted more. In my very dry SG2 layup, the Kevlar had lots of pale blotches visible over the painted areas. Looked scary at the time, but the skin has not delaminated yet.
Jun 30, 2004, 02:05 PM
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Quote:
Originally Posted by briandlg
Any good links to info on building your own CNC system for these purposes? I have heard that Les' cores are very good...but at $40 a set, I can't order in the quantity needed to experiment.
Most interesting to me is John Ihlein's (local pilot and builder) efforts. He used plans from Dennis Ray (DRAY Inc) to build very inexpensive x and y tables out of MDF (medium density fiberboard) and drawer slides. He and and another local pilot are getting good results with that machine.

I am using HobbyCNC electronics (good!) and another company's (not to be named) X/Y tables. All parts are good except the drive screws--they are not straight. One screw I asked him to replace, but the replacement was even more bent. I expect to replace them locally with custom-machined parts.

You might want to recalculate your costs. I doubt you can save money on a few wings by building your own machine. If you want to make your own CNC because it is interesting, by all means do so. We are having fun doing just that. You just want to realize that you can get a lot of cores at $40-80 each before you reach the cost of a good CNC setup. Figure $400-500 at the low end for electronics and hardware, or many times that plus your effort to create a system approaching what a pro like Les has.

Quote:
Please do report back. I'll be very curious to hear how they turn out. I too have been on the hunt for the white foam scrap from surfboard companies...I would imagine I have easier access here in SoCal than you do in NM. I'll let you know if I hit pay dirt.
Yes--First to find white surfboard foam reports back for all. It should be (approximately) 2 lb. extruded polystyrene with a vertical grain.

-Aradhana Singh
Jun 30, 2004, 02:38 PM
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I'll jump into the fray now........

With regards to the tail surface weights, would a shaped contest balsa horizontal and vertical tail that was sealed with clear dope be in the right neighborhood as far as weight goes, and would it be strong enough?

I'm close to bringing a CNC mill online (maybe this weekend) and have created the files to cut a SuperGee horizontal tail. After I wring out the 2 dimensional cutting, I was going to give the 3 dimensional cutting a test using the SuperGee tail files.

Should be interesting.......

John Ihlein
Albuquerque, NM
Jun 30, 2004, 02:53 PM
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Any good links to info on building your own CNC system for these purposes?
We have here in Europe a lot of pages with good CNC foam cutter systems. Some are in german language, but you can translate them with google.
http://gm.cnc.free.fr/index_en.html
http://people.freenet.de/NC-FRS-Tech...deMechanik.htm
http://home.t-online.de/home/wolfgang.watzke/
http://www.thiemig.de/
http://www.8linx.com/cnc/cnc.htm
http://www.geocities.com/CapeCanaver...87/control.htm
http://www.teaser.fr/~abrea/cncnet/t.../spartia.phtml
http://www.infolaser.net/franpr/tecn...m/cncfoam.html

For me the first link is the best! The machines on the other sites are using the same software and interface partly.
I've bought my machine from Haase in a prefinished version and did the rest of building work myself.
Nevertheless I've problems to cut the tails without burning the foam to much at the very small tips.

Christian from Germany
http://ch.baron.bei.t-online.de


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