HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Jan 10, 2012, 05:00 AM
Sic itur ad Astra
sparks59's Avatar
United Arab Emirates, Abu Dhabi, Abu Dhabi
Joined Aug 2009
1,603 Posts
Thanks guys. It wasn't until I posted the photo of the stab progress that I thought about it...and then realised that it needed further work, other than shaping the outer edges to plan. A bit of careful thought will get me a positive location on the fuse and jointly support the fin squarely.
sparks
sparks59 is offline Find More Posts by sparks59
Reply With Quote
Sign up now
to remove ads between posts
Old Jan 10, 2012, 10:56 PM
Sic itur ad Astra
sparks59's Avatar
United Arab Emirates, Abu Dhabi, Abu Dhabi
Joined Aug 2009
1,603 Posts
Made a little bit more progress on the tail group yesterday evening. Built up the fin, rudder and added the support on the horiz stab. I still have to add support on the stab for the fin but will leave this until all the adhesive is dry.

Apologies for the quality of the photo's, I had to use the mobile phone camera!

sparks
sparks59 is offline Find More Posts by sparks59
Reply With Quote
Old Jan 15, 2012, 03:44 AM
Sic itur ad Astra
sparks59's Avatar
United Arab Emirates, Abu Dhabi, Abu Dhabi
Joined Aug 2009
1,603 Posts
At last got to the board yesterday afternoon to make a little progress on the Raven.

Installed the tail group, slotted without glue for now, and added the upper longerons to the rear fuselage, i'll cut them at the rear former to allow the tailplane removal for covering etc when dry.

Motor test installation and cut front former. Have yet to design the cone around the outrunner, need to make sure I can get air to it, but I dont want a 'blunt' front!

I had already cut out the rib blanks and was deliberating on how to build the wings with a little more strength to accommodate the increased loading which will occur with RC operation compared to FF rubber, batteries, servos, motor etc

Anyway, decided to leave the existing number of ribs but add an upper spar, both spars to be 3/16 sq.

I have yet to make a dihedral brace, which will be plywood and will be slotted in behind, or in front of the upper spar, with some extra bracing on the ribs. The brace will be tapered at each end to avoid a large strength differential.

Dihedral, I haven't decided how much I'll have. Plan would be 5", i.e. 2.5" each tip if I follow the plan of 1.25" on the 18" span. I think I'll probably have about 2" each tip, any thoughts on this guys?

sparks
sparks59 is offline Find More Posts by sparks59
Reply With Quote
Old Jan 15, 2012, 04:59 AM
Registered User
owlsabie's Avatar
South Africa
Joined Feb 2009
2,684 Posts
She's looking great Sparks
owlsabie is online now Find More Posts by owlsabie
Reply With Quote
Old Jan 15, 2012, 05:34 AM
Sic itur ad Astra
sparks59's Avatar
United Arab Emirates, Abu Dhabi, Abu Dhabi
Joined Aug 2009
1,603 Posts
Thanks Owl. I'm trying to make as much progress as possible because I'm away again most of next weekend, and the following one i'll be off to Vietnam for two weeks holiday.

sparks
sparks59 is offline Find More Posts by sparks59
Reply With Quote
Old Jan 15, 2012, 07:05 AM
I like real wooden aeroplanes!
Sundancer's Avatar
South-west France
Joined Sep 2007
4,426 Posts
Excellent progress Sparks. On dihedral; my usual rule of thumb for rudder controlled models, carried forward from what we used on R/E controlled thermal soarers, is "1 inch per foot of semi-span plus 1 inch under each tip" which would equal 2.5" under each tip, this always worked well on models of 2 metres and upwards. However, on smaller span models I tend to change the "plus 1 inch" to "plus half an inch", which would make it the 2 inches you were thinking of, and that's what I would use.
Sundancer is offline Find More Posts by Sundancer
RCG Plus Member
Old Jan 15, 2012, 09:00 AM
Sic itur ad Astra
sparks59's Avatar
United Arab Emirates, Abu Dhabi, Abu Dhabi
Joined Aug 2009
1,603 Posts
Thanks for the re-enforcement advice George. I also took the old adage of 'if it looks right then it probably is alright'. Now set up and the glue is drying. I'll custom make and fit the ply brace when the basic structure is dry. I don't usually bother, but as this is a low wing model, I have also 'set in a 1/4" of washout. I think it will be a little less than this when the support is taken away, maybe around 1/8th, but I think a little bit might aid the flying characteristics.
sparks
sparks59 is offline Find More Posts by sparks59
Reply With Quote
Old Jan 15, 2012, 01:01 PM
I like real wooden aeroplanes!
Sundancer's Avatar
South-west France
Joined Sep 2007
4,426 Posts
A little bit of washout never did any harm Sparks - it's like the "10 knots extra for the wife and kids" on a landing approach! My "Swannee" low wing R/E model had the recommended washout built in and it's behaviour was exemplary.
Sundancer is offline Find More Posts by Sundancer
RCG Plus Member
Old Jan 16, 2012, 07:03 AM
Sic itur ad Astra
sparks59's Avatar
United Arab Emirates, Abu Dhabi, Abu Dhabi
Joined Aug 2009
1,603 Posts
Love the Swannee, what a lovely model.

Latest progress photo's from the work done yesterday evening follow:

Wings now joined and braced, I used a 1/16th ply brace and glued it up with good old pva, I don't know why as I usually always use epoxy for things of that nature. Hope that they will be ok for the rigours of flight...or more to the point, the rigours of my landings

Also made a bit of progress on making and trimming the nose block. Its not quite deep enough yet, so I may trim the fuse a little to allow another layer building the correct shape. Yet to decide on this tbh.

I still have a tailwheel / skid to do, upper fuse sheeting at the front, removable chin section. Wing retention. Spats of some description. Canopy, control gear, elevators....the list is getting longer!

I put it on the scale with all the gear, 750 2s lipo receiver, servo's everything apart from the control rods. It's currently 10.25 oz. I think it will probably end up at around 11 oz, which should be alright for the style of flying power train I have selected.

Just need to determine the receiver / servo's / battery location. If possible, I want the battery accessible from the chin cover and the receiver / servos above the wing. The esc should fit behind the motor mount former. It will be fairly tight getting a 750 / 800 mah 2s battery in there I know.

thanks for reading

sparks
sparks59 is offline Find More Posts by sparks59
Reply With Quote
Old Jan 16, 2012, 03:31 PM
I like real wooden aeroplanes!
Sundancer's Avatar
South-west France
Joined Sep 2007
4,426 Posts
Told you it woul be a quick build Sparks! Looking good.
Sundancer is offline Find More Posts by Sundancer
RCG Plus Member
Old Jan 16, 2012, 10:37 PM
Sic itur ad Astra
sparks59's Avatar
United Arab Emirates, Abu Dhabi, Abu Dhabi
Joined Aug 2009
1,603 Posts
My Mille post!

You were right George, the Raven build is going reasonably quickly, and i'm still away from the board a lot of the time. I though it was going to be relatively uncomplicated but it really is an easy build with a low count of simple component cuts.

I'm pleased with the result so far, thinking of sheeting the centre section of the wing, maybe with 1/32 balsa or possibly 1/64 ply, to spread the load a little and also I hope to achieve a clean(er) fit to the fuselage 'arch'.

I haven't yet worked out the detail as i'm torn between my old fashioned preference for a traditional bands and dowel fixed wing and the desire to 'tidy up' the look a little. I'm currently thinking of a short pair of dowel pegs in the leading edge to locate into the U/C former to positively centre and secure the wing at the fore. It's the TE that I havent decided. The easy option would be a small nylon screw / bolt, but this method of fixing has no elasticity, therefore, small faux pas almost never go unpunished. My current thought is to have a tab on the TE which can be easily retained to a transverse dowel by a band, or two. The other method in my head, which may prove to be far too fiddly, is to have what I shall refer to as "the cotton reel tank" method of fixing, using a short dowel peg connected to the inner fuse by an elastic band. This is stretched and poked through a small hole and will sit flush into a slot. The difficulty I can envisage is finding a band with sufficient stretch to install, but tight enough to hold the wing. All comments and thoughts would be most welcome.
sparks
sparks59 is offline Find More Posts by sparks59
Last edited by sparks59; Jan 16, 2012 at 10:38 PM. Reason: typo
Reply With Quote
Old Jan 22, 2012, 01:54 AM
Sic itur ad Astra
sparks59's Avatar
United Arab Emirates, Abu Dhabi, Abu Dhabi
Joined Aug 2009
1,603 Posts
More progress on the little Raven.
Made the 'chin' section, but still need to make the retainers when Final shaping is nearly finished.

Also decided to sheet all of the upper fuse at the front, rather than just the cockpit section. I think it is better to increase the weight slightly rather than risk it with the weight of the motor / battery etc in that area. Used 1/16th sheet so the weight penalty is not too bad.

Hope i'll still be able to install the servo's so they'll be accessible under the wing. No comments or suggestions on wing fixing guys?

sparks
sparks59 is offline Find More Posts by sparks59
Reply With Quote
Old Jan 22, 2012, 02:38 AM
Registered User
owlsabie's Avatar
South Africa
Joined Feb 2009
2,684 Posts
She's looking great there Sparks! Unless you really feel the need to make a more interesting way of attaching the wing, I would still go with rubber bands, just because it easy
owlsabie is online now Find More Posts by owlsabie
Reply With Quote
Old Jan 22, 2012, 05:18 AM
Registered User
Yak 52's Avatar
UK
Joined Jan 2009
1,248 Posts
The cowling looks good Sparks.

I like the dowels or tab method for the LE.
What about a pair of neodynium magnets for the TE?


Jon
Yak 52 is offline Find More Posts by Yak 52
Reply With Quote
Old Jan 22, 2012, 05:46 AM
I like real wooden aeroplanes!
Sundancer's Avatar
South-west France
Joined Sep 2007
4,426 Posts
Hi Sparks, good to see it coming along. I was wondering like Jon if two pairs of rare earth magnets at the back with either a tongue or dowels at the front might be OK, they certainly get a good grip when I use two on hatches, especially if you use magnets on each side rather than a magnet and a tinplate patch. Trouble is, you wouldn't know what the permissable stress was until you exceeded it and the wing fell off - a bit "all or nothing" maybe! It would be difficult to get an internal rubber band tight enough at the trailing edge I think, but how about combining the two so that the magnets do the holding and the band is there for insurance, in which case it won't need to be quite so tight and the wing could still swivel in an impact?
Sundancer is offline Find More Posts by Sundancer
RCG Plus Member
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Contest Build off for FROG designs October 1st 2011 to April 30th 2012 Sundancer Vintage & Old-Timer Designs 237 Apr 23, 2013 03:29 PM
Discussion FROG Build Off Raven Yak 52 Free Flight 58 Oct 31, 2012 04:50 AM
Build Log FROG Build-Off Wren X2 Raf_Bob Vintage & Old-Timer Designs 55 Apr 07, 2012 07:45 PM
Build Log FROG Build-Off Widgeon X2+ orange&white Vintage & Old-Timer Designs 13 Nov 05, 2011 04:26 PM
Build Log Frog Build-off - Wren X2[ATTACH]4325080[/ATTACH] [ATTACH]4325081[/ATTACH] [ATTACH]4 Raf_Bob Vintage & Old-Timer Designs 2 Oct 06, 2011 05:13 PM