HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Jul 30, 2012, 08:26 AM
Registered User
United States, PA, Easton
Joined Feb 2010
65 Posts
Ross,

Mine is moving along nicely...I've got the fuse together, and will get the bottom piece on tonight...It's so small its hard to lock it down to the bench, but it has come out nicely, almost self jigging...The nose block should go on shortly...I need to order Mark's tow hook...

Did you adjust the incidence on the stab? Mark mentioned 1 degree, but I wasn't clear on which line to use at the reference....

I have a five year old and a soon to be three year old, so its hard to find time dedicated to strictly building....

I did punch out the wing ribs this morning, so the wing will be following soon....

What size battery did you use? Which receiver did you use?..I can't find the micro stamp that Jack used in his..Has your flown lately?

Gordon
gordonnora is online now Find More Posts by gordonnora
Reply With Quote
Sign up now
to remove ads between posts
Old Jul 30, 2012, 04:40 PM
Registered User
Mark Miller's Avatar
St. Louis, MO
Joined Oct 2002
2,715 Posts
Gordon,

I reised the trailing edge of the stab by about 1/32 which should give another half degree of decalage. I think that should work out well. I decided to move the stab as lowering the trailing edge of the wing required many more changes.

I have ordered the first run of production parts so I should have some kits soon.

Mark
Mark Miller is offline Find More Posts by Mark Miller
Reply With Quote
Old Jul 30, 2012, 04:43 PM
Registered User
Mark Miller's Avatar
St. Louis, MO
Joined Oct 2002
2,715 Posts
BTW...On mine I used a Hyperion 850 mah LiFe pack and two Airtronics 94814 servos. I used those servos to cut the holes in the servo tray. These are about the same size as Hitec HS-85. The Hyperion DS-13 should work great too.

Mark
Mark Miller is offline Find More Posts by Mark Miller
Reply With Quote
Old Aug 04, 2012, 11:12 AM
Registered User
Mark Miller's Avatar
St. Louis, MO
Joined Oct 2002
2,715 Posts
Well of course things could not go easily. I sent in the order for laser parts and the laser my laser guy uses is broken. He is working with eht mfg. to find the issue and get it repaired. It is a big 100 watt unit which makes better quality stuff especially on thick balsa and ply. No ETA on when it will be fixed. Be patient guys. It will be there.

Mark
Mark Miller is offline Find More Posts by Mark Miller
Reply With Quote
Old Aug 04, 2012, 12:36 PM
Registered User
United States, OR, Corvallis
Joined Jan 2010
931 Posts
Washout or Not??

Hi, I skimmed around and maybe I missed it, but just curious if anyone has put washout into the wingtips of their Duets or not?

And if "Not", then I'm curious about "Why not?" what is it about the tips or overall design that allows for not needing/wanting washout, is the airfoil at the tips different than at the root or midwing? Or do some constant-through-the-wing airfoils just do nicely and not need it, and what feature of the airfoil(phillips entry? thinner vs thicker? highpoint before, right on, or behind the top spar? etc) avoids stalling in tips? the top/bottom view outline shape of the tips? Sheeting vs turbulators from leading edge to top spar?

Thanks - Paul
Pauliwog is offline Find More Posts by Pauliwog
Reply With Quote
Old Aug 04, 2012, 01:21 PM
Wood Chucker
Lacquerhead's Avatar
USA, TX, Allen
Joined Nov 2009
1,500 Posts
With careful airfoil choices washout isn't strictly needed on all designs. Drela's design for the Supra uses different airfoils across the span and effectively increases thickness at the tips. That increase in thickness delays localized stall which allows the root to stall first. Sure you can stall the entire wing but if you enter slowly, say in a thermal or turn on landing, you have an opportunity to recover before the stall becomes terminal. Washout is most commonly used when the airfoil is constant across the span to avoid stalling the entire wing at once.

Of course I'll defer to Mark since it's his design.
Lacquerhead is offline Find More Posts by Lacquerhead
Reply With Quote
Old Aug 04, 2012, 02:28 PM
Registered User
Mark Miller's Avatar
St. Louis, MO
Joined Oct 2002
2,715 Posts
I left washout out of the equation mostly because of the relatively long chord and thickness of the airfoil at the tip. I scaled the ribs in all directions when sizing and so are the same relative thickness for their chord. I did not find any issues with tip stalling when testing.

I think the term tip stalling is one of the most misunderstood terms out there. Often added regardless of if it is needed and often to much is used. It is usually used when a plane is flown to slowly in a turn and the inside wing stalls. Of course stalling is unavoidable ultimately as a plane flying to slowly will stall regardless. It is up to the pilot to keep it flying.

You can add some if you like. You guys are the builders and they are your planes after all.
Mark Miller is offline Find More Posts by Mark Miller
Reply With Quote
Old Aug 04, 2012, 03:35 PM
Registered User
United States, OR, Corvallis
Joined Jan 2010
931 Posts
Thanks for the washout/tip-stall info......

Good info and interesting.

Mark Miller- I agree, I've seen some of the electric guys at the field call every single stall a "tip stall" and I've given up explaining it since I get that unspoken look of "what do you know, you're a woodie glider flyer, what a simpleton". Other than that, that's a great looking plane.

Lacquerhead - Interesting about the relative thicker airfoil at the tips, that's exactly what the 2M standard Spirit has, and even though I did thin and modify my airfoil on that completely modified Spirit 2M I just built, I did let it transition to a relatively thicker-toward-the-tip configuration. I think since I sheeted to the tip, I probably ended up with more washout built in than what I needed. I recently looked more closely at it and I think I have really close to 3/8". It turns buttery smooth fast or slow but I think it was overkill and 3/16" would have been possibly better, yet, it still stays in the air longer than anything I've built yet so I'm not going to mess with it or complain.

Thanks for the info-Paul
Pauliwog is offline Find More Posts by Pauliwog
Last edited by Pauliwog; Aug 04, 2012 at 05:31 PM.
Reply With Quote
Old Aug 04, 2012, 08:36 PM
Registered User
Mark Miller's Avatar
St. Louis, MO
Joined Oct 2002
2,715 Posts
Paul,

www.isthmusmodels.com

Buy some stuff so I can go to the NATS next year. I miss it.

Mark
Mark Miller is offline Find More Posts by Mark Miller
Reply With Quote
Old Aug 05, 2012, 06:46 PM
Full Scale Better! UOHHHH!
Phoebusflyer's Avatar
United States, TX, Lytle
Joined Dec 2006
396 Posts
I just did! I hope it helps!
Allen
Phoebusflyer is offline Find More Posts by Phoebusflyer
Reply With Quote
Old Aug 05, 2012, 08:08 PM
Registered User
Mark Miller's Avatar
St. Louis, MO
Joined Oct 2002
2,715 Posts
Thanks Allen,

The kit will be shipped tomorrow.

Mark
Mark Miller is offline Find More Posts by Mark Miller
Reply With Quote
Old Aug 08, 2012, 12:08 PM
Be the duck. Whaaaa?
UberZogster's Avatar
United States, CA, Guerneville
Joined Mar 2012
312 Posts

I was looking at this picture and started wondering, what are you using 3400 grit paper on?
UberZogster is offline Find More Posts by UberZogster
Reply With Quote
Old Aug 09, 2012, 12:39 AM
Wood Chucker
Lacquerhead's Avatar
USA, TX, Allen
Joined Nov 2009
1,500 Posts
I use it to polish metal and plastic/putty on fine scale plastic models. I could see using 1200 grit before primer on a painted plane or 1200-2200 wet on primer or between color coats on a painted plane. Properly done paint can be lighter than plastic film. I have yet to do it properly though. I'm just not patient enough sometimes.
Lacquerhead is offline Find More Posts by Lacquerhead
Reply With Quote
Old Aug 09, 2012, 05:59 PM
Hot Dawg Glider Pilot
schrederman's Avatar
United States, TX, Weatherford
Joined Nov 2002
7,762 Posts
3400 is the paper series, not the grit. That's actually 120 grit in the pic...

Jack... (Darth Trailer Trash)
schrederman is offline Find More Posts by schrederman
Reply With Quote
Old Aug 09, 2012, 06:55 PM
Be the duck. Whaaaa?
UberZogster's Avatar
United States, CA, Guerneville
Joined Mar 2012
312 Posts
Okay, I was like 3400!!! What am I missing?
UberZogster is offline Find More Posts by UberZogster
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Build Log Build Log - STARFIRE! Mc Clain Wing Cores 48" Beta Build pval3 Flying Wings 548 Nov 16, 2013 10:34 PM
New Product Scale Military UAV / Drone Beta-Kit Build/NOW WITH VIDEO! pattypilot Electric Warbirds 140 Mar 01, 2012 12:28 PM
Discussion Isthmus Models Duet Beta Build StevenatorLTFO Sailplane Talk 158 Sep 16, 2011 08:34 PM
Discussion Rollason Beta quick-build Sopwith Mike Scale Kit/Scratch Built 74 Jul 27, 2011 03:45 PM
Discussion Kit/Plane fun build contest-Hawker Typhoon beta build baldguy Scale Kit/Scratch Built 268 Oct 07, 2009 11:58 PM