New Products Flash Sale
Thread Tools
Old Mar 20, 2014, 11:34 AM
miniphase is offline
Find More Posts by miniphase
Registered User
miniphase's Avatar
United Kingdom, Kent
Joined Nov 2004
897 Posts
Discussion
2 metre...no, make that a 4 metre motor glider!!

I started a new wing last week. The main role for this design will be for calm evening flying from my back garden. Too many still days have gone to waste, and from now on they will be enjoyed with an airbourne wing!...or at least they will be when I finish it!

I cut the cores from pink foam, inserted a 1/32nd ply shear web, and laid carbon fillets in. The spar is complete overkill as this wing will be bagged in glass, and the section is pretty thick so will lack top speed, but better to be safe than sorry.

I'll build it with elevons to start with, but may add flaps once I've flown it.

I doubt there'll be anything ground breaking design or construction wise, but doing a thread will keep me motivated to 'get 'er done' (I hope!)
miniphase is offline Find More Posts by miniphase
Last edited by miniphase; Feb 17, 2015 at 02:37 PM.
Reply With Quote
Sign up now
to remove ads between posts
Old Mar 20, 2014, 07:50 PM
HerkS is online now
Find More Posts by HerkS
Herk
HerkS's Avatar
Virginia USA
Joined Jun 2007
1,725 Posts
subscribed
HerkS is online now Find More Posts by HerkS
Reply With Quote
Old Mar 21, 2014, 06:36 AM
Drinkes is offline
Find More Posts by Drinkes
Registered User
Ukraine, Crimea, Ordzhonikidze
Joined Jul 2012
61 Posts
My 2 metre wing. Very similar design. Profile PW75. Weight about 1800gramm

Flyingwing 2000мм (2 min 38 sec)
Drinkes is offline Find More Posts by Drinkes
Reply With Quote
Old Mar 21, 2014, 12:34 PM
Jon Snow is offline
Find More Posts by Jon Snow
You know nothing....
Jon Snow's Avatar
Joined Sep 2011
3,590 Posts
Jon Snow is offline Find More Posts by Jon Snow
Reply With Quote
Old Mar 24, 2014, 02:48 PM
Knoll53 is online now
Find More Posts by Knoll53
less is more
Knoll53's Avatar
United States, CA, Marina
Joined Sep 2006
3,188 Posts
Quote:
Originally Posted by miniphase View Post
I cut the cores from pink foam, inserted a 1/32nd ply shear web, and laid carbon fillets in. The spar is complete overkill as this wing will be bagged in glass, and the section is pretty thick so will lack top speed, but better to be safe than sorry.
A "motor" glider ......who knew ! That should give you a few more options. Your pink foam looks different than mine.

I like your method of slicing up the cores to drop a spar in first. Looks quick. Have you ever tried attaching bias glass with 3M77 per the sketch, roll on some epoxy, lay on the CF tow, then smashing it all together? Might be quicker and could be stepped down to lighter construction towards the tips.

Since you have a spar, you have the option to go very light on the skins if you want.......it's a good thing.
Knoll53 is online now Find More Posts by Knoll53
Reply With Quote
Old Mar 25, 2014, 04:24 AM
KNS is offline
KNS
Find More Posts by KNS
KNS
Registered User
Switzerland, SO, Olten
Joined Dec 2012
465 Posts
subscribed!
KNS is offline Find More Posts by KNS
Reply With Quote
Old Mar 26, 2014, 04:55 PM
miniphase is offline
Find More Posts by miniphase
Registered User
miniphase's Avatar
United Kingdom, Kent
Joined Nov 2004
897 Posts
Drinkes- that looks like a lovely wing, I don't want to go for vertical performance so cruising around at a similar speed to yours would be fine. Any idea how many watts / lb you're running at there?

Kent- yup, I was thinking of fairly light weight skins, maybe with a double layer of cloth in the D box area.

The pink foam I use is different to the stuff over in the US. The impression I get is that it's somewhere between your pink and blue foams in terms of density. I like the stiffness the ply shear web gives, but need to work on the slot cutting for the tows as I've had to fill over the top. I need to spend an evening or two making a sanding tool that gives a guaranteed depth, and then do some trial runs with wetted out tows to get the correct fill. I'd also thought about something similar to your sketch, but running glass or carbon all the way around.

Anyway, back to the build. I've had a few days delay as my thumb had an argument with a saw at the weekend, but I have melted out the slots for the joiner tubes. These will have a carbon tube set in them, back filled with Gorilla glue.....
miniphase is offline Find More Posts by miniphase
Reply With Quote
Old Mar 28, 2014, 07:19 AM
Drinkes is offline
Find More Posts by Drinkes
Registered User
Ukraine, Crimea, Ordzhonikidze
Joined Jul 2012
61 Posts
Quote:
I don't want to go for vertical performance so cruising around at a similar speed to yours would be fine. Any idea how many watts / lb you're running at there?
Around 100 watt / lb. RimFire 1200 3536 11x7 3S.
Drinkes is offline Find More Posts by Drinkes
Reply With Quote
Old Mar 31, 2014, 05:53 AM
miniphase is offline
Find More Posts by miniphase
Registered User
miniphase's Avatar
United Kingdom, Kent
Joined Nov 2004
897 Posts
Thanks Drinkles, I had 100w/lb in mind too.

Next stage- I laid the carbon joiner tubes into the oversize holes, made sure all was square and then tacked them in with Gorilla glue. Once this had set, I stood the wing on end and filled the rest of the void with same. I didn't use any moisture, as I wanted as dense a foaming from the glue as possible.
miniphase is offline Find More Posts by miniphase
Reply With Quote
Old Mar 31, 2014, 09:52 AM
Knoll53 is online now
Find More Posts by Knoll53
less is more
Knoll53's Avatar
United States, CA, Marina
Joined Sep 2006
3,188 Posts
It's amazing how little moisture it takes to set off PU glue.

Will there be a separate joiner rod that fits inside of the joiner sleeve already installed or will this be a one piece wing?

Also, do you have any sketches of the intended structure to be added around joiner? Would like to see them.

Kent
Knoll53 is online now Find More Posts by Knoll53
Reply With Quote
Old Mar 31, 2014, 10:48 AM
miniphase is offline
Find More Posts by miniphase
Registered User
miniphase's Avatar
United Kingdom, Kent
Joined Nov 2004
897 Posts
The wing will be two piece Kent, the joiner set up shouldn't need to be too beefy as this will be quite a slow flying, lightly loaded model.

The joiner tubes just about sit in a opening in the shear web, then there'll be a ply root rib that the other end will be set in. There will also be some localised carbon reinforcement in the bagging layup....
miniphase is offline Find More Posts by miniphase
Reply With Quote
Old Mar 31, 2014, 12:04 PM
Knoll53 is online now
Find More Posts by Knoll53
less is more
Knoll53's Avatar
United States, CA, Marina
Joined Sep 2006
3,188 Posts
Just a thought......... even with light loads.

With the aft placement of the alignment pin, the root ribs are an important part of the transfer of torsion loads. Do you see an advantage in some sort of connection at the main spars with less need for strong root ribs?

It's a different way to do the same thing......I know.

Kent
Knoll53 is online now Find More Posts by Knoll53
Reply With Quote
Old Mar 31, 2014, 02:58 PM
miniphase is offline
Find More Posts by miniphase
Registered User
miniphase's Avatar
United Kingdom, Kent
Joined Nov 2004
897 Posts
Yes that might help Kent....I'm designing 'on the hoof' and need to plan the pod to house the lipo etc. I want to keep it as low profile as possible, so I may need to hollow out some of the area in front of the spar or joiner to house various bits and bobs. I can see how the forward alignment pin would offer a better transfer of loads....I'm hoping there may still be room to do this even if I cut into the wing for 'payload'.
miniphase is offline Find More Posts by miniphase
Reply With Quote
Old Mar 31, 2014, 03:40 PM
Knoll53 is online now
Find More Posts by Knoll53
less is more
Knoll53's Avatar
United States, CA, Marina
Joined Sep 2006
3,188 Posts
Quote:
Originally Posted by miniphase View Post
....I'm hoping there may still be room to do this even if I cut into the wing for 'payload'.
The rear alignment pin is all that is needed to handle torsion loads, as long as you can "get to it" structurally. With a mighty patch of FRP, you could connect all together AND provide a nice shell in front to hollow out for those bits and bobs.
Knoll53 is online now Find More Posts by Knoll53
Reply With Quote
Old Apr 02, 2014, 07:55 AM
miniphase is offline
Find More Posts by miniphase
Registered User
miniphase's Avatar
United Kingdom, Kent
Joined Nov 2004
897 Posts
Great minds think alike Kent! I may still need a bit of a pod / bulge underneath to hide the guts. At this stage I'm thinking of lost foam and carbon cloth as the best way to get it done...
miniphase is offline Find More Posts by miniphase
Reply With Quote


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion New releases by flyfly hobby-3 Metre fox , 2.6 Metre ask21 gliders Damian Couzoff Australia 12 Jul 26, 2010 05:11 AM
Discussion first scale glider, 1.5 - 2 metre, plans or artf mrdoodah Scale Sailplanes 3 Oct 29, 2009 10:41 AM
Biggest brushless ESC I am likely to need for a 2 metre glider? Peter Young Electric Sailplanes 31 Jun 17, 2004 04:48 AM
45 or 60 amp esc for 2 metre glider? Peter Young Power Systems 1 Jun 13, 2004 06:39 AM