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Building Tips and technical articles. => Building techniques => Topic started by: Avaiojet on November 24, 2012, 07:39:19 AM

Title: Tube in a Tube, Hinge for Stab & Elevator?
Post by: Avaiojet on November 24, 2012, 07:39:19 AM
With all this talk about taping gaps and flight improvements with doing so, and it does make plenty of sense, I'd like to close my gaps, on The International, as tight as possible without using tape. Even when the R/C pattern guys were using tape, I just couldn't bring myself to using it. Cleanup, maintenance, replacement, all of that.

So, with this said, and I hope the die hard tape users don't get offended, gotta remember, I don't compete, so I'm not looking for competition quality in my models. I'm looking more towards a building challenge and something a bit different is what I would say my motovation is.

Now I have used short cut sections of tubes which were used as bushings and pivot points for control surfaces in scale models. However, I have never used a tube in a tube the full length of the control surface.

I have seen photos of modelers using CF rods in their airplanes, but nothing up close or detailed that would aid me in this construction?

I really don't want to spend any money for CF rods, but I would consider it as plan B.

I do however, already have aluminum tubing that could possibly fit the bill.

I've been sizing this stuff over my stab/elevator drawing to get some ideas about how I'm going to pull this off.

As you can see from the photo, the stab and elevator is 26" in span and .75" thick. The thickness is one of the reasons I would like  to rule out a "V" cut elevator.

I'm hoping someone has done this before?

Thanks in advance.

Charles

 
 
Title: Re: Tube in a Tube, Hinge for Stab & Elevator?
Post by: Avaiojet on November 25, 2012, 10:23:47 AM
Here's the before and after.

I ran the TE and LE through the table saw, twice actually for each knotch.

Each rib is a difference size, times two.

Cutting the ribs and assembly is next.

Charles
Title: Re: Tube in a Tube, Hinge for Stab & Elevator?
Post by: John Hammonds on November 27, 2012, 03:10:21 PM
Hi Charles,
 Not sure if this is the sort of example you are interested in but Frank Wadle did a nice build sequence on a German control line forum. The post covers almost the complete build but there are some photos of how he does his hinges using tubes and nylon inserts.

Here's the link (Translated into English hopefully).

http://translate.google.co.uk/translate?hl=en&sl=de&u=http://fesselflugcenter.kostenloses-forum.be/fesselflugcenter-beitrag97.html&ei=obDBTprZJYOq8QOd5b2PBA&sa=X&oi=translate&ct=result&resnum=1&ved=0CCMQ7gEwAA&prev=/search%3Fq%3Dhttp://fesselflugcenter.kostenloses-forum.be/fesselflugcenter-beitrag97-0-asc-0.html%26hl%3Den%26sa%3DG%26prmd%3Dimvns

TTFN
John.
Title: Re: Tube in a Tube, Hinge for Stab & Elevator?
Post by: Avaiojet on November 27, 2012, 04:50:39 PM
John,

Thanks for that.

Someone posted that extraordinary model before and made comment about how there wasn't a speck of balsa sawdust inside the covering.

I don't remember seeing that build thread but do remember seeing a few construction photos.

I love the bellcrank setup. Same thing I do but I use two of the std. aluminum ones. 3" actually.

I would prefer that setup but don't have a source for the over and under bellcrank? Can you help me with that?

That modeler has tremendous building capabilities.

I saved the sight and the build!

Thanks again.

Charles
Title: Re: Tube in a Tube, Hinge for Stab & Elevator?
Post by: Mark Scarborough on November 27, 2012, 08:23:13 PM
The Ballerina used this style hinges......late fifties or early sixties era as I recall.there are pictures on Herr somewhere,,,,perhaps a search would turn them up. Searching on my tablet is slow....
Title: Re: Tube in a Tube, Hinge for Stab & Elevator?
Post by: Avaiojet on November 28, 2012, 06:24:47 AM
The Ballerina used this style hinges......late fifties or early sixties era as I recall.there are pictures on Herr somewhere,,,,perhaps a search would turn them up. Searching on my tablet is slow....

Mark,

Thanks for the reply.

I did that search and came up empty.

I made these drawings in CAD and took a photo of the screen, quicker this way to make a JPEG.

The englarged view shows the construction I have in mind. You can see the overlap of material above and below the LE of the flap. Small arrow shows overlap material and area of concern.

45 degrees of deflection is shown, should be plenty?

I expect to work on this tonight or tomorrow.

Thanks again for the reply Mark, it's nice to hear from you.

Charles