SMALL - espritmodel.com SMALL - Telemetry SMALL - Radio
Reply
Thread Tools
Old Sep 06, 2012, 03:03 PM
Closed Account
Joined Jul 2009
745 Posts
Hi Stuart,

Well just watching this thing move is fun and worth a few views alone just to see it swing. I did say I might like to build one of these ... or something like it and well yeah there are a few tentative sketches but nothing concrete. In reading that it flies as well is quite interesting and yeah a video would be really good. But ok that will come in time I am sure. Again my hat is off and respect Stuart !! this is quite a piece of work.

Jens
kleinaberfein is offline Find More Posts by kleinaberfein
Reply With Quote
Sign up now
to remove ads between posts
Old Sep 06, 2012, 04:55 PM
_
Joined Aug 2012
36 Posts
I'll be in my bunk!
g_munu is offline Find More Posts by g_munu
Reply With Quote
Old Sep 06, 2012, 05:04 PM
Just call me crash for short
Quick61's Avatar
United States, OH, The Plains
Joined Jan 2011
1,697 Posts
Quote:
Originally Posted by g_munu View Post
I'll be in my bunk!
"War Stories", my personal 2nd favorite.
Quick61 is offline Find More Posts by Quick61
Reply With Quote
Old Sep 07, 2012, 08:45 AM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
3,376 Posts
Well yesterday was an unmitigated disaster.We found a good field,but the wind was too strong.Waited a bit,and in what seemed like a calm spell tried a throw into the wind.Of course a gust caught it,straight back over my head and a crunched wingtip resulted.
The wing is definitely fluttering,so I'm going to try some layers of packaging tape.
The blind nuts are only into balsa on the underside,I'll reinforce these as well.The outer one on the damaged wing has pulled into the wood.
Then rebalance and wait for a calm day.
Stuart
Stupot46 is offline Find More Posts by Stupot46
Reply With Quote
Old Sep 07, 2012, 09:01 AM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
3,376 Posts
Kent,same drive,must be the reduced load.
I think I can make something resembling your sketch for the nuut,I'll give it a try
A sketch for the pivot points-probably later today

Mark,some of those co wings look ok(to my untutored eye).Some thing pretty docile to begin with,if we use a foam wing it will be easy enough to try more adventurous types later.
Serenity- hmmm
Stuart.
Stupot46 is offline Find More Posts by Stupot46
Reply With Quote
Old Sep 07, 2012, 10:37 AM
less is more
Knoll53's Avatar
United States, CA, Marina
Joined Sep 2006
2,873 Posts
Quote:
Originally Posted by Stupot46 View Post
Well yesterday was an unmitigated disaster.
It's never a disaster when you learn something. Here in my neighborhood, we call a wingtip like that a "bump". Looks to be still flyable.

Sorry, I'm not keeping up. Is this still a chuck glider??? That is no RC.

Kent
Knoll53 is offline Find More Posts by Knoll53
RCG Plus Member
Latest blog entry: Sw-11
Reply With Quote
Old Sep 07, 2012, 11:43 AM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
3,376 Posts
Quote:
Originally Posted by Knoll53 View Post

Sorry, I'm not keeping up. Is this still a chuck glider??? That is no RC.

Kent
Still and always will be.Everything on the wing is 2mm.I thought that wrapping the balsa round the l/e and two carbon spars would be enough.I'll have a read up on the best way to use tape and see what that will do.A bit more weight won't hurt any way.
Stuart
Stupot46 is offline Find More Posts by Stupot46
Reply With Quote
Old Sep 07, 2012, 02:50 PM
Closed Account
Joined Jul 2009
745 Posts
Bummer Stuart sorry to see the mishap but it looks like a minor bit damage so no worries and glue it back together.

Jens
kleinaberfein is offline Find More Posts by kleinaberfein
Reply With Quote
Old Sep 07, 2012, 03:19 PM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
3,376 Posts
Thanks Jens.the repair is easy,stopping the wing flexing not so.I wish Ellie had filmed it,but with it popping back over me she missed every thing.Flutter gets mentioned a lot on these pages,but I can honestly say that is the first time I've seen it so pronounced.Tape first,then maybe double up the forward carbon rod if that doesn't work.
Stuart
Stupot46 is offline Find More Posts by Stupot46
Reply With Quote
Old Sep 07, 2012, 03:39 PM
Herk
HerkS's Avatar
Virginia USA
Joined Jun 2007
1,652 Posts
Stuart - most of these flutter because of flexibility in bending at the root connection. You may need only to stiffen the rotational structure. Stiffening the wing panel alone may not help. Check to see if there is a lack of stiffness in that inboard area first.
HerkS is offline Find More Posts by HerkS
Reply With Quote
Old Sep 07, 2012, 04:28 PM
Just call me crash for short
Quick61's Avatar
United States, OH, The Plains
Joined Jan 2011
1,697 Posts
While were on the subject of inboard and outboard, there is something that has been bothering me for a few days now. I keep hearing that the pivot point should be further out on the wing, right? But I am also observing the plethora of compound swept wings all over this forum. Just look at the dozens of threads here with those type.... Oh wait, there aren't any.(or maybe 1 with the tip section swept back a bit extra?) My point being that I think that the variable sweep wing out further from the center has a lot more to do with tailed, supersonic jets than it does with low RE model flying wings. Should we not maybe be thinking more about the strength and movement of the wing and just try to keep in line with Stuarts chuck glider as a design starting point? Sure, there needs to be a bit larger fuse to accommodate the mechanical bits and all - but trying to move the variable sweep point out further? What do you all think?

Mark
Quick61 is offline Find More Posts by Quick61
Reply With Quote
Old Sep 07, 2012, 04:33 PM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
3,376 Posts
Thanks Herks,insightful as ever! The base plate is only balsa,which is not holding the captive nuts on the four through bolts.I plan a ply reinforcement here,weight should still be ok.
Everything I've built in the past has been from kits or plans,so this little item is the first thing I've put together myself.
At least I know it's capable of flight,I just need to get it strong enough.
Regards Stuart.
Stupot46 is offline Find More Posts by Stupot46
Reply With Quote
Old Sep 07, 2012, 04:59 PM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
3,376 Posts
Oops
Stupot46 is offline Find More Posts by Stupot46
Last edited by Stupot46; Sep 07, 2012 at 05:02 PM. Reason: Repeating myself!!
Reply With Quote
Old Sep 07, 2012, 05:09 PM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
3,376 Posts
Mark,I think it was yours truly who raised this after reading up on swing wings.The reason NASA stated was to lessen the % of wing moved and so reduce the effective cog shift.The relative length of our wing will probably make any gain negligible.
Stuart
Stupot46 is offline Find More Posts by Stupot46
Reply With Quote
Old Sep 08, 2012, 02:39 AM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
3,376 Posts
A question for our cad designers.First a disclaimer in case what follows is nonsense.I have no idea what your programmes are capable of.
Would it be possible to lay out a planform of a swing wing,and move the wings through the full sweep?I'm thinking if so by taking measurements at points along the sweep we can calculate exactly what the cog is doing.
If the wing movement will to some extent self correct the balance,could this and(Kents?)idea of weight in the wing be be sufficient?
The rough and ready three position measurements I took from the chuck glider would suggest that a weight could be tuned to move the same distance as the cog to balance the wing.The only drawback with the wing weighting is that it would move in an arc.
The above was prompted by the fact that the belt and pulley drive could have been used to move a weight,not so the latest version.
We will need to determine if cog shift needs to be built into the drive- this could be done using the linear belt drive I sketched out in a earlier post,the underside of the belt moving the weight.
Stuart
Stupot46 is offline Find More Posts by Stupot46
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Best electric plane in 16 mph wind? Sailor03 Electric Plane Talk 42 Nov 23, 2012 03:40 PM
Discussion Why do airplanes take off in to the wind? - news article jduvall Electric Plane Talk 65 Jun 15, 2012 08:29 AM
Discussion Make Sure Your Wind Turbine Is In The Wind Big Foot 48 Life, The Universe, and Politics 0 Apr 04, 2012 10:22 AM
Help! DJI Naza wind issue!!!! (help needed with throttle up issue in wind) Arxangel Multirotor Talk 11 Mar 07, 2012 02:47 AM
Sold ~closed~ WINDSHEAR II Aircraft - Fuel - Engines and Accessories (FS/W) 2 Oct 14, 2011 12:15 AM