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Old May 06, 2012, 09:03 PM
Visitor from Reality
United States, VA, Arlington
Joined Dec 1996
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Hi Sparks
At least you don't spend a lot on mowing grass.

Sorry...

My Raven 2X has 2" dihedral under each tip - or 4" total if you look at it that way - which amounts to seven degrees each side.

Unfortunately, I didn't video any flights and recently gave the model to a flying buddy as a way to hopefully wean him off that foam stuff and as a 'thank you' for his support and visits over my last year's medical problems.

See attached - a rare head-on shot, which shows the dihedral on mine pretty well. I think she has a little more dihedral than your version, but measuring is the only way to be sure. She had very snappy roll response on the whole, though RE low wingers tend to be a little slower coming off a steeper bank angle than RE high wingers in my experience.

The wing structure is not that stable. My biggest worries, however, turned out to be waterproofing and surviving being blown off tables at the flying field. Heat resistance has yet to be a problem in Chicagoland

Hope that helps

Dereck
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Old May 06, 2012, 10:52 PM
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Warren B's Avatar
Mt Evelyn, Melbourne, OZ
Joined Dec 2008
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Rudder Elevator can be a bit odd on low wingers, but the oddness can be worrying or charming, depending on degree.

My Lola falls into the charming group.
Pefectly controllable just doodling around, but a roll can tend to "hang" in the inverted position for some time. So barrel rolls ore more fun.
Steep turns can also "dig in" a bit, but not too worrying.

Lola has 38" wingspan and 3 1/4" under each tip, about 10 degrees.
It also has the CG about 50%, but does not seem too elevator sensitive (and it does have a great glide).

I went with ailerons on my Raven just for a change, and because I thought it would suit the character of the little Ollie (which it does).
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Old May 07, 2012, 08:29 AM
Visitor from Reality
United States, VA, Arlington
Joined Dec 1996
12,788 Posts
Was sitting here barely post-breakfast, wondering what the switch in the fuselage side near the TE could be for.

Then I remembered - you can't plug a BEC into a diesel

Yes, a R/E low winger can be 'different'. Fortunately, my first one was designed by someone who really knew what he was doing, so it flew real well and gave me a set of 'numbers' to follow from there on. Attached photo is a crushingly simplistic one I built not long before leaving Maryland - it ended up with a clubmate back there. Easier to build another than pack for a multi-state move!

D
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Old May 07, 2012, 11:44 AM
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sparks59's Avatar
United Arab Emirates, Abu Dhabi, Abu Dhabi
Joined Aug 2009
1,603 Posts
Your no ailywagglers looks about a simple as it could be Dereck. Like it.
As for Warrens Lola, love it.
Checked the incidences last night, they are as near to plan as I can tell, a degree or so negative on the horiz stab.
The dihedral is 3.25inch total, I reckon I should have stuck with the 4 inches for this one. Anyway, i'll add a little slice of the church roof in the nose and give it a go next time out!

cheers guys
sparks
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Old May 07, 2012, 02:17 PM
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South-west France
Joined Sep 2007
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3.25" total is a bit stingy Sparks. Using the old formula which has stood me in good stead of 1" per foot of semi-span + 1" per side would give 2.5" per side, 5" total. I might have backed off a touch as it is a small model, but wouldn't have gone below 4.5 " total.
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Old May 09, 2012, 02:22 PM
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United Arab Emirates, Abu Dhabi, Abu Dhabi
Joined Aug 2009
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Sure you are right George. I don't know how I ended up with it as small as I did, I had intended to set it at about 4", slightly less than the 'ideal' for FF. That probably another obstacle for achieving nice turns.

sparks
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Old May 09, 2012, 09:32 PM
Visitor from Reality
United States, VA, Arlington
Joined Dec 1996
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Scratting in the memory banks here, but the seven degrees a side on my 2X is only a tad less than the 'full size' Raven. Good thing about FF models - they go around in a fairly steady state without some goofball on the ground messing with the trim all the time.

D
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Old May 11, 2012, 05:58 AM
RFJ
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Northern Ireland
Joined Dec 2004
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Sparks- if it's of any use I used 2.5" under each tip on my Speedy which is about the same size as your Raven I think ( 40" span) Rudder response is excellent and it holds in a turn until corrected.

By the way I don't see your name on the BritKits buildathon yet There must be something you fancy.

I like your flying site - and I thought we had some good beaches in my part of the world

Ray
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Old May 11, 2012, 12:04 PM
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United Arab Emirates, Abu Dhabi, Abu Dhabi
Joined Aug 2009
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Hey Ray,
The beach is alright, but the tide goes out further than at Cleethorpes
Your dihedral figures fit right in with those mentioned by George and others, I really haven't got quite enough. But I'll trim and balance some more and see if its response can improve, if not, i'll have to rethink it.


For sure i'll be joining the Britkit fun with something, and there are lots that I like, but i'm currently working in Iraq so havent really had chance to sit with my plan list or sift through the web to see what i'm going to build. To be honest, I'd like to build a KK Chipmunk, the only reason being I built a rubber power one as a young modeller and I can't remember if it ever flew. I do remember lots of awkward formers, stringers and very small pieces fitting intricately together. Conversion to a small leckky job would not be hard, but its another low wing semi sport job....so I may do something else....
sparks
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Last edited by sparks59; May 11, 2012 at 12:17 PM. Reason: 't
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