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Old Dec 08, 2012, 11:52 AM
Herk
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Virginia USA
Joined Jun 2007
1,645 Posts
John - sorry to hear that you weren't feeling well.

This is a really interesting build log. Thanks for keeping it going.
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Old Dec 09, 2012, 08:30 AM
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Colchester UK
Joined May 2004
411 Posts
Thanks Herk, just wanted to contribute for a change.

Well having wrestled the second leading edge skin into place and secured it with brown tape I was at last able to fix some of the easier panels.

Cleaned up the first leading edge and pleased to say the glue joint was near perfect. The second one looks to have pulled up nice and tight as well.

John
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Old Dec 10, 2012, 05:50 PM
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sawman's Avatar
Louisiana
Joined Oct 2005
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Very nice build, John. My hat is off to you Sir !
I don't know how some people can make such a rugged build that LOOKS so good. When I build, it looks like........well, let's just say I'd be ashamed to show any photograhic evidence. (Cover quickly with dark opaque covering ! )
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Old Dec 11, 2012, 06:19 AM
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Colchester UK
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Thanks for the encouragement. Actually I think it looks a bit messy, but I guess the builder will only see all the faults. It is quite difficult to keep the ply surfaces free from glue covered fingers, despite being really as careful as I can. As I mentioned before this is my first attempt at a ply covered model. So far I am reasonably happy with the results, but the key thing will be the weight.

I have been watching the weight increase as I work on the plane. The basic airframe as far I have is now just over 2 Kg with the turbine and other parts at another Kg. I still hope to have the model weigh 3.4Kg, but we will see. Most of the ply covering is now on so will be able to glue the leading edge on. Not sure what to do about the cockpit and turbine. At the moment I am leaning towards a non scale low profile canopy and an exposed engine to save weight. Weight at the back of the plane is bad news as it inevitably requires nose weight to compensate.

It is very difficult to get used to not having to sand the plane after adding panels. If they are cut the right size and shape then they should fit with minimal sanding. Also the shin thickness only allows 0.2mm of sanding before the glue joint in the ply grins through.
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Old Dec 12, 2012, 10:46 AM
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Colchester UK
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Final pieces fixed to the underside. Almost done with the sheeting. In the end I used 1.6mm thick sheet on the nose section, 0.8mm sheet on the middle centre section under the tanks and 0.5mm at the tail. The rest of the plane was all 0.6mm sheet.

The nose leg will have a screw in panel so I can remove the nose gear easily, this will be shaped to fit the cut out for the leg.

John
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Old Dec 13, 2012, 08:16 AM
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Colchester UK
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Underside finally finished. I can now glue the leading edge on but that will be for tomorrow.
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Old Dec 14, 2012, 04:36 AM
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Colchester UK
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This morning glued on the spruce leading edge. I was surprised that spruce was specified, but I guess that it will be very tough and stand modest tumbles without damage. You can see the slightly raised panel where I used the thicker sheet in the nose area. I must let the glue set well before I do any planing of the leading edge.

I found the best way to pull the leading edge up tight against the ply was to use brown packing tape. This also keeps the parts in the correct place. The clamps are where the splice joint is located. The material was not quite long enough to make in one piece. Also the material was not quite wide enough so I glued 2 3X5mm spruce strips on each side on the section near the nose before glueing the leading edge on to the plane.

John
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Old Dec 14, 2012, 08:31 AM
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andrecillo76's Avatar
Heidelberg
Joined Oct 2009
379 Posts
Hi John,

Nice! You've made great progress! I like how you installed the landing gear. Have you decided on the canopy? It would be a pitty not to have the scale section...

Regarding the spruce leading edge. It's one of the pieces most subjected to damage during landing, etc. I made one wing with balsa and decided to never do it again, as it was full of marks soon.

Greetings from Baja California,
Andrés
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Old Dec 14, 2012, 11:29 AM
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Colchester UK
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Andres

Nice to get your comments. Yes I am happy with the retracts.

Must be warmer in Baja than in the UK, sure is building weather here at the moment! Luckily my workshop is the warmest room in the house.

I have just planed and sanded the leading edge spruce off.

I have not decided on the canopy and the engine mounting. The problem is the engine needs to be as near the CG as possible otherwise I shall need more lead to balance it. Also the tanks I chose are a problem as they are a tighter fit than I thought. I just now tried a heat gun to squash the rear of the tank down and that seems to have worked. However the tanks are quite soft so could expand when being filled. I would hate it to pop the skins off!

John
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Old Dec 15, 2012, 09:56 AM
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Colchester UK
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Finally have the plane the right way up and am able to think about the cockpit and tanks.

I heated the tanks with a hot air gun and they deformed with light pressure to fit inside the space available. I will probably add some carbon to make sure that they do not pop the ply off.
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Old Dec 16, 2012, 03:44 PM
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Heidelberg
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Quote:
Originally Posted by John Wright View Post
Must be warmer in Baja than in the UK, sure is building weather here at the moment! Luckily my workshop is the warmest room in the house.
When we left Frankfurt, we had snow and ice, and one hour delay because of de-icing. We arrived at lovely 22°C and sunshine . The weather changed for a couple of days, but probably way better than in the old continent at the moment. And else, if weather should worsen, it's like planning a barbecue in England: you always need a good alternative program

Cheers,
Andrés
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Old Dec 17, 2012, 07:29 AM
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Colchester UK
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I decided in the end to go for a fully enclosed engine. It is going to be heavier but looks better.

I remade all the formers, so that the engine had 4 degrees upwards angle rather than the down angle that was on the original design. I noticed on the videos that it caused a problem with severe down pitch on applying full power. It made takeoff very difficult as can be seen. I am sure that this will help make it rotate off grass. The engine is slightly larger diameter than the Lambert engine. The power is considerably more and needs a larger diameter tailpipe. I also need to be able to insert the tailpipe from the rear and that ensures that the formers will be slightly larger.

The photos show the checking of the angles before gluing any parts in place.
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Old Dec 17, 2012, 12:04 PM
I don't like your altitude
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Joined Sep 2011
3,277 Posts
Looks good John.Is that one of your own units?
Leading edge turned out nice.In the past I've bought lengths of pine from B&Q,they do quite a range of what they call strip wood in usable sizes.Because they stock 2.4m lengths it saves splicing.Sorting through usually yields some straight lengths.
Stuart
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Old Dec 17, 2012, 01:08 PM
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Colchester UK
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Stuart

Yes this is one of my own units. I have plenty to select from, would be nice to get 1:1 power to weight if I can find the best one, anyway it will certainly fly it well enough on 3.2 Kg.

The spruce edge strip I had with the ribs from Germany and as usual superb quality, straight grain and could not be faulted. I planed the edges with a David 4 combi plane that uses special razor blades, which worked well. I finished with a rough, then a fine cut Permagrit and fine emery paper. I think in the UK cyparis is used by LMA members as it tends to be free from faults.

John
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Old Dec 17, 2012, 05:28 PM
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Eden NY
Joined Sep 2001
540 Posts
John,
Your model is looking quite spectacular! The woodwork overall is a sight to behold but the finished leading edge gives it a look that only fine furniture woodworking has. Beautiful work. I only wish I could do half as well.

The turbine is a great unit too and this model should be impressive when flown.

Following your progress is a pleasure.
Best Regards and happy holidays!
-Eric
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