HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Jul 08, 2012, 09:55 AM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
3,285 Posts
I've made up a rack as in Bobs pic above and think I've worked out how to attach and pivot the wing for a simple test glider.What's testing the grey matter at the moment is how make the set up rigid enough at full model size.It will need to be strong enough to prevent any flexing in both direction,yet still allow the wings to swing.This won't be easy with the length of typical plank/wing spans.Thin thrust races are available at diameters of 100/150mm but will probably be too expensive.Custom making them is feasible;2hard nylon rings with a turned groove in each and a thin flat ring between perforated to hold steel balls.
Or am I over engineering;Teflon may be sufficient.
I've asked Bob if he has any more details on the F14,it may provide some pointers.
Stuart
Stupot46 is offline Find More Posts by Stupot46
Reply With Quote
Sign up now
to remove ads between posts
Old Jul 08, 2012, 03:22 PM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
3,285 Posts
Taking a cue from a well known contributor to this forum,a swing wing thing.
Using what I had to hand,a pair of KF style wings(Space1will be proud of me!)
Curving the balsa has added a good degree of stiffness.
Centre section next,the rack will just help to keep the wings in the same fixed position.
Stuart
Stupot46 is offline Find More Posts by Stupot46
Reply With Quote
Old Jul 08, 2012, 03:52 PM
which way is up?
Joined Jan 2012
37 Posts
Here's an example of a very simple f-14 mechanism.
http://www.rcgroups.com/forums/showt...=9#post8703292

F-14 wing setup (0 min 5 sec)
PilotAir is offline Find More Posts by PilotAir
Reply With Quote
Old Jul 08, 2012, 04:40 PM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
3,285 Posts
Thanks Pilotair,that's a similar system to my original idea.That F14 is a nice piece of kit,and a good flyer by the sounds of things.Do you know if the gear system in Bobs post #21 above was a mod done on that thread?
Regards Stuart
Stupot46 is offline Find More Posts by Stupot46
Reply With Quote
Old Jul 08, 2012, 08:45 PM
CNC Cutter
birdofplay's Avatar
United States, IN, Indianapolis
Joined Dec 2005
8,609 Posts
Finally back in Indy from the Dayton Airshow with grand kids in 104 deg heat !!!

That geared wing idea was never implimented. Just discussed.
It would have been used on larger versions as the original, as seen in #33, above
worked for almost all builders.

I was considering a B1 swing wing but found the rear end a bit narrow for
foamy construction.

Bob

PS sorry re bad text frags.I was in a hurry to prep for a plane trip
West coast USA to Indiana.
So I just tossed off the animation as a quicky.
birdofplay is offline Find More Posts by birdofplay
Last edited by birdofplay; Jul 08, 2012 at 08:53 PM.
Reply With Quote
Old Jul 09, 2012, 01:05 AM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
3,285 Posts
Thanks Bob.As you said elsewhere,and Herks advised earlier,I'm probably anticipating problems that may not arise.I think the gear rack is a great idea,any thing that reduces the number of servo linkages can't be bad.
Regards Stuart
Stupot46 is offline Find More Posts by Stupot46
Reply With Quote
Old Jul 09, 2012, 02:04 PM
CNC Cutter
birdofplay's Avatar
United States, IN, Indianapolis
Joined Dec 2005
8,609 Posts
Modeling is a lot about creativity and experimentation.

All improvements are welcome :-)

Some I just do as a CAD study or in my head others actually get built and tested.

I was also just going to put an individual servo on each wing Pivot.
The servo body would still be hidden in the nacelle.

To thoise guys with sticky wings I'd say wiggle the elevator while
actuating to reduce G load friction on the pivot point.

Bob
birdofplay is offline Find More Posts by birdofplay
Reply With Quote
Old Jul 09, 2012, 03:08 PM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
3,285 Posts
Bob,I'm no electronics expert.Whilst doing some research on swing mechanisms I came across a post by a college student who stated that his prof. had told him it was almost impossible to get 2 servos to work exactly in sync.The point is academic in this case,when I came up with compass leg gear idea my first thoughts were a single servo,preferably a bigger version of the linear servos Jens uses.This would need a linkage to each wing.I don't like linkages,fewer the better is best in my book.
This is the beauty of your gear rack idea,which in my opinion deserves more credit than you give it.It eliminates any hinged linkages,and guarantees(given correctly designed and cut teeth)that the wings are held at equal angles.
Regards Stuart
Stupot46 is offline Find More Posts by Stupot46
Reply With Quote
Old Jul 09, 2012, 03:40 PM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
3,285 Posts
I made a start on the lower half of the centre section.The plate is laminated from 2mm depron and balsa,the disc pivots from the last piece of 3mm I have.Next will be the infill between the wings,with enough material fore and aft to allow me to shape the edges to a reasonable shape.
Stuart
Stupot46 is offline Find More Posts by Stupot46
Reply With Quote
Old Jul 09, 2012, 09:54 PM
CNC Cutter
birdofplay's Avatar
United States, IN, Indianapolis
Joined Dec 2005
8,609 Posts
I appreciate your tenacity and modeling.

But minor differences in servo travel shouldnt make that big of a difference in flight
during the limited time during travel.
Take a chill pill and just build it ;-)

Bob
birdofplay is offline Find More Posts by birdofplay
Reply With Quote
Old Jul 10, 2012, 03:03 PM
Closed Account
Joined Jul 2009
745 Posts
Stuart ... how in the did you cut those gear teeth so nice. Come on don't hold out here I gotta know how you did this.

Jens
kleinaberfein is offline Find More Posts by kleinaberfein
Reply With Quote
Old Jul 10, 2012, 04:36 PM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
3,285 Posts
Jens,they are just marked out with a compass and cut out with the exacto,it's quite easy to follow a line with the depron having no discernible grain.I've decided against using them on this trial;incorporating them makes it difficult to make a stiff centre section.I'm just going to mark a series of positions and peg the wings.
Regards Stuart
Stupot46 is offline Find More Posts by Stupot46
Reply With Quote
Old Jul 11, 2012, 08:04 AM
CNC Cutter
birdofplay's Avatar
United States, IN, Indianapolis
Joined Dec 2005
8,609 Posts
@kleinaberfein

There used to be a dxf creating GEAR profile program out there someplace on the net.
I havent even used my copy for years but I will try to locate it when I get back
tomorrow.

As I recall you could enter pitch and diameter sizes etc.

I made a few wooden gear parts with my CNC "Just Because" I wanted to try it.
They are still hanging on a shop cabinet door.

Bob
birdofplay is offline Find More Posts by birdofplay
Reply With Quote
Old Jul 11, 2012, 08:32 AM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
3,285 Posts
Quote:
Originally Posted by birdofplay View Post
@kleinaberfein

There used to be a dxf creating GEAR profile program out there someplace on the net.
I havent even used my copy for years but I will try to locate it when I get back
tomorrow.

As I recall you could enter pitch and diameter sizes etc.

I made a few wooden gear parts with my CNC "Just Because" I wanted to try it.
They are still hanging on a shop cabinet door.

Bob
It's possible to do them by hand.I was taught the method at college,various sites on line with instructions for either method.I think the circular tooth profile would be ok for a swing wing application.
I've almost finished the centre section,need to re-read some of Herks postings about control surfaces and work out a cog for the two extremes
Stuart
Stupot46 is offline Find More Posts by Stupot46
Reply With Quote
Old Jul 11, 2012, 12:48 PM
Closed Account
Joined Jul 2009
745 Posts
I am watching and learning

Jens
kleinaberfein is offline Find More Posts by kleinaberfein
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 02:40 PM
Discussion Why do airplanes take off in to the wind? - news article jduvall Electric Plane Talk 65 Jun 15, 2012 07:29 AM
Discussion Make Sure Your Wind Turbine Is In The Wind Big Foot 48 Life, The Universe, and Politics 0 Apr 04, 2012 09:22 AM
Help! DJI Naza wind issue!!!! (help needed with throttle up issue in wind) Arxangel Multirotor Talk 11 Mar 07, 2012 01:47 AM
Sold ~closed~ WINDSHEAR II Aircraft - Fuel - Engines and Accessories (FS/W) 2 Oct 13, 2011 11:15 PM