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Old Nov 30, 2011, 09:14 AM
Hot Dawg Glider Pilot
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United States, TX, Weatherford
Joined Nov 2002
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Be sure to do just that! If I'm in town, we'll fly!
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Old Nov 30, 2011, 09:33 AM
Wood Chucker
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USA, TX, Allen
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I certainly will!
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Old Nov 30, 2011, 12:06 PM
The earth sucks! Thankfully.
United States, OK, Tulsa
Joined Jun 2003
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Mark:

Could you post a pic of the IM001TE airfoil? I would like to see just how thin the aft taper is.

Thanks,
Jim
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Old Nov 30, 2011, 12:28 PM
The earth sucks! Thankfully.
United States, OK, Tulsa
Joined Jun 2003
429 Posts
Glue for Upper Sheeting

Quote:
Originally Posted by schrederman View Post
I have the leading edges done and planed. Here's what the process looks like.
I realize this is old.

Jack,

What glue did you use for the upper sheeting and did you need water to get it to curve?

How did you hold the sheeting in place while applying the glue?

Thanks,
- Jim
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Old Nov 30, 2011, 02:20 PM
Hot Dawg Glider Pilot
schrederman's Avatar
United States, TX, Weatherford
Joined Nov 2002
7,792 Posts
Jim,

I use polyurethane glue for gluing on the top sheeting, usually... However, with this build, I used aliphatic resin (Titebond II) glue. I use phone books to keep the top sheeting pressed down. No water is necessary if you use good, medium, A-grain wood, as it bends pretty easily. I always position the books with the back just behind the spar and the opening pages to the leading edge. That allows the book to conform to the rib-top shape easier. I tape the sheeting at the spar and the leading edge with masking tape first, before outting the phone books on. I will usually stack the phone books 2 deep. Another note, I am not using books that are less than 2" thick. The lighter, thinner ones won't do you a lot of good...

With this arrangement on a flat building table, you come out with nice, straight wings. In a D-tube configuration, the bond between the ribs and the D-tube sheeting is very important for torsional rigidity. I have seen this done with contact glues and other stuff, but that is too flexible, in my opinion, for the best strength and flutter resistance.

No probelm with it being old... I am too...
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Old Nov 30, 2011, 02:35 PM
Wood Chucker
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USA, TX, Allen
Joined Nov 2009
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Drats. I just pitched a whole bunch of old phone books.
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Old Nov 30, 2011, 04:50 PM
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Mark Miller's Avatar
United States, WI, Waunakee
Joined Oct 2002
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Regarding the airfoil....

Here is a two view of the Duet. It is an earlier version but only minor details have changed. You can see the airfoil there.

Also here is the analysis of the airfoil compared to the Bubble Dancer AG. Back then it was called RES1.

Here is a quote from the designer...

This is an XFOIL Type 2 analysis, RE ~ sqrt (CL), RE 80,000 at CL = 1.

In the range of operation CL = 0.4 -> CL = 1.0 (corresponding to thermal flying), the drag of the RES1 is less than that of the AG35, at some points as much as 10% less. The AG35 is superior at CL 0.35 and below, corresponding to a flying speed of about 1.5x the usual flight speed, or faster.

The Duet is really a test bed for the airfoil. My goal is to have a new RES plane for next year using this airfoil. I have some cool ideas. Now the real trick is putting them into reality.
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Last edited by Mark Miller; Nov 30, 2011 at 09:17 PM.
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Old Nov 30, 2011, 06:54 PM
Unrepentant Paragon addict
LVsoaring's Avatar
United States, OK, Moore
Joined Jan 2006
2,640 Posts
Quote:
Originally Posted by Mark Miller View Post
Regarding the airfoil....

Here is a two view of the Duet. It is an earlier version but only minor details have changed. You can see the airfoil there.

Also here is the analysis of the airfoil compared to the Bubble Dancer AG. Back then it was called RES1.

Here is a quote from the designer...

This is an XFOIL Type 2 analysis, RE ~ sqrt (CL), RE 80,000 at CL = 1.

In the range of operation CL = 0.4 -> CL = 1.0 (corresponding to thermal flying), the drag of the RES1 is less than that of the AG35, at some points as much as 10% less. The AG35 is superior at CL 0.35 and below, corresponding to a flying speed of about 1.5x the usual flight speed, or faster.

The Duet is really a test bed for the airfoil. My goal is to have a new RES plane for next year using this airfoil. I have some cool ideas. Now the real trick is putting them into reality.
I hope one of the cool ideas is a 3+ meter version!
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Old Nov 30, 2011, 07:41 PM
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United States, WI, Waunakee
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That is the plan. it is time to replace the Soprano.
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Old Nov 30, 2011, 08:07 PM
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Dallas, TX
Joined Jan 2005
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Mark,
What is the rough date of when the Duet will be up for sale?
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Old Nov 30, 2011, 09:02 PM
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Mark Miller's Avatar
United States, WI, Waunakee
Joined Oct 2002
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I am happy with what I see with this build. Looks like we have things sorted. I have flown two of them so far and know that they fly great.

At this point the only remaining piece is a manual. Using Jack's build thread and some photos I already have there should be about to finish that. I'd like to have a few for sale by the New Year.
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Old Dec 01, 2011, 08:38 AM
Hot Dawg Glider Pilot
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United States, TX, Weatherford
Joined Nov 2002
7,792 Posts
Amarillo weather is turning to crap... which is good for building... so, unless I have weather related emergencies for the railroad, I intend to finish this model this weekend. This week, my job has been intense, but things are slowing down. I should be able to post some progress tonight.
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Old Dec 01, 2011, 06:27 PM
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Quote:
Originally Posted by Lacquerhead View Post
Drats. I just pitched a whole bunch of old phone books.
Errr...how about a vacuum instead of the books?
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Old Dec 01, 2011, 06:28 PM
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Quote:
Originally Posted by Mark Miller View Post
Regarding the airfoil....

Also here is the analysis of the airfoil compared to the Bubble Dancer AG. Back then it was called RES1.
Is the airfoil proprietary?
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Old Dec 01, 2011, 06:39 PM
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United States, WI, Waunakee
Joined Oct 2002
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Yes it is Dave
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