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Vintage Models KK Elmira

Build problems

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Pauil Ashford13/07/2020 15:56:37
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16 forum posts
53 photos

I have come up against a problem with the Vintage Models kit of the KK Elmira in that the wire supplied for the wing join is 10 SWG (3.25mm) but the tubing in which it is intended to fit is 8 SWG, not a snug fit!

A route around in my spares box produced some 4mm ally tubing that will take the 10 gauge wire with a little persuasion. However I do not have enough for the job so ordered some more from a local supplier (ATM4), on receiving the new stock I found the wall thickness was greater and the 10 gauge wire could not be persuaded to fit.

Has anyone out there had this problem and could share their solution please.

Thanks, Paul.

Cliff 195913/07/2020 16:13:48
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516 forum posts
77 photos

Can't you go back to VM and ask for the correct tubing? I don't see why you should be put to all this trouble?

Pauil Ashford13/07/2020 17:20:10
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16 forum posts
53 photos

Cliff,

Done that and they have been trying to sort it out with their suppliers, the problem seams to be tubing is now manufactured in millimetres diameter, and the 10 swg wire I suspect is the problem. They can find a fit at 12 gauge but this would not be optimum for the bending moments at the wing join. I and working with VM to come up with a solution but thought I would through this out there to see if anyone else had come up against the same problem.

Colin Bernard13/07/2020 17:47:31
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503 forum posts
93 photos

I agree with Cliff - it is for VM to sort out and if they can only get metric tubing, then they should provide equivalent metric wire! Not for you to have to mess about to find a solution to their problem.

Richard Clark 213/07/2020 19:52:04
418 forum posts
Posted by Pauil Ashford on 13/07/2020 15:56:37:

I have come up against a problem with the Vintage Models kit of the KK Elmira in that the wire supplied for the wing join is 10 SWG (3.25mm) but the tubing in which it is intended to fit is 8 SWG, not a snug fit!

A route around in my spares box produced some 4mm ally tubing that will take the 10 gauge wire with a little persuasion. However I do not have enough for the job so ordered some more from a local supplier (ATM4), on receiving the new stock I found the wall thickness was greater and the 10 gauge wire could not be persuaded to fit.

Has anyone out there had this problem and could share their solution please.

Thanks, Paul.

Better to use 8 SWG wire. 10 is very thin for a model that size.

Piers Bowlan13/07/2020 20:40:13
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2167 forum posts
53 photos

If Vintage Model Kits don't come up with a solution you could try some K & S tubing (ali or brass) to fit the wire you have if possible, or alternatively substitute a metric dia. steel or carbon fibre joiner and tube to fit. SLEC also do wing joiner tubes of all sizes.

Piers Bowlan13/07/2020 20:42:15
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2167 forum posts
53 photos

Ops, double post!

Edited By Piers Bowlan on 13/07/2020 20:53:34

Nigel Sharp13/07/2020 21:39:26
31 forum posts
147 photos

I think I'd use Carbon Rod and matching tube(s) if I was to build a new wing.

Be aware that most of the bending load is actually taken by the spruce tongue inserted between the spars. My advice here is to make sure you can slide this spruce into both the centre and tip panels. They do break occasionally if the landing catches a tip and swings/pivots the tip against the center panel.

I have an original KK Elmira still flying. It was refurbished and updated in 2006 to include ailerons and reduced dihedral.

The original was known for poor rudder response and I concur hence my addition of ailerons. Keep speed up too as the wing tips are narrow with a fairly thick aerofoil. Mine has a vicious tendency to drop a wing if slowed too much. But it is a fine flyer otherwise.

Pauil Ashford13/07/2020 22:14:08
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16 forum posts
53 photos

Nigel,

I had come up with the same solution, 5mm carbon rod slides in nicely to the 8swg brass tube supplied so I'd probably use that. Interesting you mention the spruce joiner, this isn't supplied in my kit and I plan to replace with another carbon rod between the spars to take the bending loads on the spar. I have also incorporated ailerons having heard of the turning problems and top surface spoilers to help control landing accuracy like on my old 100s models.

I am working with VM to resolve this and other problems with the kit and plan, it was a kit they acquired from another producer and they wish to update the drawing and get it right.

Thanks for your input.

Nigel Sharp14/07/2020 10:41:47
31 forum posts
147 photos

Pauil

For completeness here are some photos of the ORIGINAL KK wing joining method and one photo taken this morning of my "pink and cream" Elmira assembled (one day I'll find a suitable pilot my daughters "Barbie" was just too big to fit when the refurb took place 2006).

Note I have the wires and spruce at different lengths as this helps aligning three interfaces doing 1 at a time.

I've not flown since 2014/15 my Son has little interest in models and is very keen on competitive Kayaking so am just getting back to my aeromodelling with lockdown enforced spare time.

Since the piano wire joiners are a bit rusty I'll have a bit of a job to get the wing tips back off!!!

Certainly been good value I think I paid about £12 for the kit back in 1981 about 30% of my apprentice wages!

Nige

KKElmira_assembled.jpgWingJoinerUnderside.jpgWingJoinerTop.jpg

Pauil Ashford14/07/2020 12:06:07
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16 forum posts
53 photos
Posted by Piers Bowlan on 13/07/2020 20:40:13:

If Vintage Model Kits don't come up with a solution you could try some K & S tubing (ali or brass) to fit the wire you have if possible, or alternatively substitute a metric dia. steel or carbon fibre joiner and tube to fit. SLEC also do wing joiner tubes of all sizes.

Thanks Piers, normally I would just go down to my nearest model shop and go through their stock of K&S parts but difficult because of the current pandemic. I've never bought so much on line in the past months but sometimes you need to just go and look!

Pauil Ashford14/07/2020 12:14:44
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16 forum posts
53 photos

Nige,

Thanks for the photos, makes it clear how the original kit worked. I guess the two 10 gauge wire are little more than incidence pegs and the mail flight loads are carried by the spruce insert. Shows it's free flight heritage.

When I get time I'll create an album on here to show construction progress.

Paul.

Pauil Ashford14/07/2020 12:45:20
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16 forum posts
53 photos

Album added, KK Elmira build Vintage Model Co.

20200430_144853.jpg

Nigel Sharp14/07/2020 13:00:17
31 forum posts
147 photos

Pauil,

Yes I agree FF heritage.

This joiner is more than adequate I used a Bungee in the 1980's. The wings do flex quite a lot but are a very consistent U across the whole span. Even the KK build instructions drew the users attention to this.

But I prefer slope flying because of longer flights (batteries permitting) which it now enjoys 100%.

Do not fly without that spruce or other (carbon) stiffener if using 10SWG piano wire otherwise the wings will flap like a bird.

Mine had a mishap about 1984/5 coming out of a booming thermal, being Rudder Elevator only back then I had to loop/spin (really a spiral dive) to get down. I preferred looping but one of the Spruce joiners took exception to the strain after about 30 loops and I know of the flappy wings as a consequence.

The model did get some damage and went into storage for a long period as I'd become interested in model yachting.

When it was refurbished by adding aileron and computerised TX I can now use a spoileron/elevator mix and application of that dips the whole wing downward if at quite (for vintage glider) high speed. So your adding spoilers is a good move.

Enjoy your Elmira.

Nige

Nigel Sharp14/07/2020 13:29:21
31 forum posts
147 photos

Nice pictures of the build.

I notice the aft section of the fuselage is rectangular section and that confirms my thoughts of what the VM kit would be like. On the original it is Trapizodal with the top edge about 1/4" to 3/8" narrower than the bottom. I'd confirm but its hard to measure along the tail boom now since mine was built all those years ago. The front section is as you have it. The sides are parallel upto and including the former at the wing Leading edge. Then the top and bottom sheet is heavily rounded to make it slender.

Sorry the picture may not be too clear...trapizoid_formers_aftWing_LE.jpg

Since the plan misses the formers I can understand why the VM co would have created rectangles. This was the old kit makers way of ensuring kits were bought not copied.

N

PatMc14/07/2020 23:52:10
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4430 forum posts
538 photos

The Elmira is a model I've long admired. It's nice looking design based on an era when full size gliders had more individual character than the modern all glass ones, albeit the performance is in a different league.

Pauil & Nigel, I'm look forward to some pics & hopefully video of your Elmiras in action soon.

Three or four times in the mid 1970's I went to the Isle of Man model gliding week & took part in the competitions. One of the slope comps was launch, climb, then as many loops as you could manage in a set time followed by a spot landing.
One year a regular competitor entered flying a nicely built & decorated Elmira. I remember he was called Arthur (possibly Bailey) he was completely deaf but could lip read, a really nice chap & very popular cheerful character.
Anyway Arthur's Elmira had caught a lot of attention so when his turn came most of the other competitors stopped whatever they were doing to watch.
He launched & climbed OK then started the loops. As he reached about 5 we all started to count and call out the numbers right up to the 20th consecutive loop when there was a spontaneous burst of applause.
After his spot landing Arthur had the biggest grin possible & went around telling everyone he encountered that he'd just managed 20+ consecutive loops. The funny thing was that Arthur was completely unaware of the attention he'd attracted & of course he hadn't heard the applause. I think it was the most popular model competition win I've ever witnessed.

Pauil Ashford15/07/2020 08:33:53
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16 forum posts
53 photos

PacMac,

Thank you for the kind words, indeed I always admired the classic lines of this model and when looking to build Lockdown 4!! thought it was about time. It was originally intended to be a winter project but with time on my hands.... The build is progressing slowly, compounded by a few head scratching issues, but will be completed before the autumn. Photos will be added to the album as I go along.

Paul

Pauil Ashford19/07/2020 20:01:16
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16 forum posts
53 photos

20200719_184806.jpg

Wiring added for airleron and spoilers with Multiplex connector at wing join. Sheeting commenced with trailing edge, 3/32" washout added at tip tapering to Airleron root. Some builders have reported tendency to drop a wing if slowed up so washout added as an attempt to counter this. Time will tell.

Pauil Ashford24/07/2020 13:27:54
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16 forum posts
53 photos

20200724_105918.jpgOuter panels fully sheeted, servo boxes finished and tips added. Ailerons cut out ready for final shaping.

In the end these panels came together nicely now need to move back to the centre panel and complete that.

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