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Building and flying the LST 1/2A Trainer

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Building and flying the LST 1/2A Trainer

Old 01-05-2005, 02:28 AM
  #51  
Bipe Flyer
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Default RE: 1/2A trainer anyone?

Actually the plans say 3 to 4 channel, and in a post above I mentioned the dihedral depending on how many channels you want. Personally, I think that it is best to learn 4 channels because it better prepares a person for other planes. I fly 2, 3 and 4 channels myself.
Old 01-05-2005, 02:34 AM
  #52  
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Default RE: 1/2A trainer anyone?

Don't get me wrong, the Plans are great, and you're right, it wouldn't take much to make it a 3 channel anyway.

Looks like this might make it into my stable, once the GF leaves me alone again!
Old 01-11-2005, 09:25 PM
  #53  
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Default RE: 1/2A trainer anyone?

I've decided to pin this message since it's the closest thing we have to an RCU endorsed trainer so far. Hopefully we'll see some construction pics and flying reports soon.
Old 01-17-2005, 07:42 AM
  #54  
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Default RE: 1/2A trainer anyone?

I agree with Bruce, this plan is worth being a sticky. I feel it could be a great model for first time builders and flyers. What I'd really love to see is this thread become a construction article for the plan. As such, I think it would be great if we could start off with a bill of materials for the plane. While some woods are clearly marked, some aren't (or my eyesight is so bad I can't see the markings.) I'd appreciate a little help in this area as I've never built from plans before and I believe that the first step would be to understand the plan completely before cutting wood.

Going with the bill of materials step, I'd like to start with the wing.

RIBS - What would the ribs be made from? 1/16" medium balsa?
SPARS - I see the spars are from 3/16" square sticks, but what sort of wood? Would balsa be adequate, or would they need to be made from firmer wood such as basswood?
LEADING EDGE - 1/4" square balsa sticks
TRAILING EDGE - 1/4" square balsa sticks
AILERONS - 1/16" x 1/2" balsa strip
SHEETING - 1/16" balsa sheet
SHEER WEBS - I read mention of these earlier on in the thread. What would they be made from? 1/16" balsa sheet?
WINGTIPS - I see no mention of how these are constructed nor what material to construct them from. A more detailed explanation of how the ends of the wings are to be constructed would be a great help here.

Well, thats it for now, I personally can't wait to get started on this build. I'm going to be realistic about it though and anticipate a slow build as I learn to interpret the plans and cut the parts as accurately as possible. Hope you guys can help me out and point me in the right direction.
Old 01-17-2005, 11:02 AM
  #55  
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Default RE: 1/2A trainer anyone?

>RIBS - What would the ribs be made from? 1/16" medium balsa?

Yes

>SPARS - I see the spars are from 3/16" square sticks, but what sort of wood? Would balsa be adequate?

Yes

>SHEER WEBS - I read mention of these earlier on in the thread. What would they be made from? 1/16" balsa sheet?

Yes

>WINGTIPS - I see no mention of how these are constructed nor what material to construct them from. A more detailed explanation of how the ends of the wings are to be constructed would be a great help here.

When the wing nears completion, cut the lower spar flush with the outer rib and leave the upper spar extended as shown. Cut a wingtip from 1/16" or 3/32" sheet in the general shape shown on the plan, but oversized. Place the straight portion of this tip against the bottom edge of the outer rib. The idea is to allow the end of the wingtip to be tilted upward until it comes in contact with the upper spar. You must decide how much of an angle you want the tip to be raised -- 45 degrees will work, but both tips must be the same. Your options are to bevel the bottom side of the upper spar where it contacts the tip or, if your wing is still pinned down (my recommendation), cut a notch in the wingtip to allow the upper spar extend thru the tip. Bevel the straight portion of the tip so that it fits flush with the bottom of the outer rib when the tip is correctly oriented. Once you are satisfied with the fit, then glue.

Here's why we cut a slightly oversized tip: The contour of the tip will likely not exactly match the upper shape of the ribs. Using a sanding bar (I sometimes tape the top of the wing ribs to avoid sanding them down), work it from leading edge to trailing edge removing the excess from the top of the tip. When finished, the upper portion of the wing tip will have the same contour as the airfoil. When the wing is lifted from the building board, you can then sand the remaining portion of the upper spar flush with the bottom side of the wingtip.

1/16" or 3/32" -- 1/16" can be used, but will probably need a couple of gussets to retain the shape when covering. Using 3/32" will not give much weight penalty and adds some rigidity to the tip.

The attached image would be looking from the trailing edge forward before sanding the upper portion of the tip to shape and removing the extended portion of the spar.

Hopes this helps.
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Old 01-17-2005, 09:51 PM
  #56  
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Default RE: 1/2A trainer anyone?

Yes, Andrew, that was a great help. Thanks a bunch! It didn't occur to me the wingtip was at an angle. I thought the top spars were cut at an angle and went down to the wingtips.

Moving on to the fuselage now.

SIDES - 3/32" balsa sheet
TOP & BOTTOM - No indication, but I'm guessing 3/32" balsa sheet as well
F1 - Plywood, but what size? would Lite Ply do? If I can't source for the proper size plywood, can I use cafeenman's method of making plywood?
F2 to F4 - What size sticks are these made from?
LANDING GEAR MOUNT - Made from 1/16" and 3/32" plywood, but I'm not entirely sure I understand how to construct it.
SERVO MOUNTS - I assume this is left up to everyone's preferred method.

As for the tail feather, they're both from 3/32" balsa I believe. What kind of hinges would be appropriate for these, as well as the ailerons?

Thanks again for your help.
Old 01-17-2005, 11:02 PM
  #57  
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Default RE: 1/2A trainer anyone?

Hello Serendpt --

It has just occurred to me that you may be working from the expanded thumbnail in one of Bipe Flyer's previous posts. Bipe (Andrew Donatelli) has set up a MSN Group called [link=http://groups.msn.com/12Aalltheway/]1/2A All the Way [/link] and has posted full size plans of the LST 1/2A Trainer on the site. You may have to join (membership is free) to view the plans.

When the site loads, choose Documents, then Plans, then either LST-1/2A-Trainer.gif or LST-1/2A-Trainer.pdf The gif file will open with your browser. You will need [link=http://www.adobe.com/products/acrobat/readstep2.html]Adobe Reader[/link], free download, to open the pdf file.

All dimensions and much greater detail are available in these plan sets -- study these; I think almost all of your questions will be answered. If not, post again.

Regards,
Old 01-17-2005, 11:38 PM
  #58  
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Default RE: 1/2A trainer anyone?

Andrew,

I am using the gif file (which I had printed) from the 1/2A All the Way site, as well as referring to the PDF file from the same site. You'll have to excuse my ignorance as far as being able to understand the plans as they are, I've been brought up on a diet of ARFs and very few kits, which usually come with most of the parts cut, as well as including an construction or assembly manual. While I have learned an acceptable amount from building the kits, I'm a long way off from being able to understand what the designer intended just from looking at the plan. Some of the construction techniques employed in Mr. Donatelli's design are unfamiliar to me, especially the landing gear. I'm sure many of the more experienced builders here had no problems understanding the plans, and probably made changes to suit their own preferred construction techniques. I'm just not at that level yet

Anyways, this Friday is a public holiday here, so I'm going to start on the wings then, hopefull I'll have some decent progress and photos sometime next week.
Old 01-28-2005, 11:28 AM
  #59  
John A
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Default RE: 1/2A trainer anyone?

ORIGINAL: Bipe Flyer

If you want a good CAD program that is easy to learn, try Turbocad. They used to have a free version at http://www.turbocad.com , but I can't find it there anymore. The free version I have is 5.1 from 1998, but you can get version 8 for around $10 on eBay.
If you type free turbocad into google, you can find plenty of mirrors of the free learning edition still up. This link will get you to one of them.
http://www.al-ki.com/tcad/download.php#TurboCADLE

Where did you get the 1/2A Library from? Any others? Inquiring minds want to download
Old 01-29-2005, 12:19 AM
  #60  
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Default RE: 1/2A trainer anyone?

Here's a Bill-of-materials that I made up. Bipe- How about adding a gear detail? I can't tell what your intentions were. How is the dihedral attained. The wing is shown as one piece. If it's a trainer then newbies will be building it.


Wings
Ribs - 3/32 Balsa Sheet 3"x36" (1)
Spars - 3/16 Square Balsa 40" long (2)
TE Sheeting - 1/16 Balsa Sheet 1/2"x37" (2)
Sheeting - 1/16 Balsa Sheet 16" long (1)
Leading Edge - 1/4 Square Balsa 40" (1)
Trailing Edge - 1/4 Square Balsa 40" (1)
Aileron - 3/16x3/4 Trailing Edge 37" total (1)
Shear Webs not shown but could be added using 1/16 sheet
on the front and back of spars with vertical grain

Fuselage
Sides 3/32 Balsa Sheet 4"x26" (2)
F1 - 1/8 Plywood
F2 - 3/32 Balsa Sheet in 5/16 and 3/8 widths
F3 - 3/32 Balsa Sheet in 5/16 and 3/8 widths
F4 - 3/32 Balsa Sheet in 5/16 and 3/8 widths
(F2-F4 can be made from scraps)
Landing Gear is 1/16 ply 5/8 wide and 5/16 tall
Tail Feathers - 3/32x4x36 Balsa Sheet
Gear wire is approx 3/32
Old 01-29-2005, 12:26 AM
  #61  
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Default RE: 1/2A trainer anyone?

Oh yeah, the ailerons are shown in the wing plan as 1/8x3/4 but on the ribs you show 3/16x3/4 trailing edge stock.
Old 02-03-2005, 11:21 AM
  #62  
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Default RE: 1/2A trainer anyone?

I don't know if anyone else knows this already or not but the Sig Kadet has already been previously scaled down for 1/2A use and was published as a construction article in M.A.N(Nov-94).The name of the plane was "Kadetito" and it used a .074 engine for power.Wingspan was 39" and the length was 31".It is plan number FSP11941 if anyone is interested.Here is some site info on this particular plane.Very similiar planes indeed.

http://www.davenportrc.org/imglib/ga...hil_kadeti.jpg

http://www.rcstore.com/rs/general/li...d=39&catego=PL
Old 02-03-2005, 07:01 PM
  #63  
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Default RE: 1/2A trainer anyone?

--but this plan is free!
Old 02-03-2005, 07:23 PM
  #64  
Bipe Flyer
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Default RE: 1/2A trainer anyone?

I haven't been getting updates on this thread since it stickied, so I only just read the last bunch of suggestions. I'll make the changes to the plan and re-upload it.
Old 02-03-2005, 09:32 PM
  #65  
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Default RE: 1/2A trainer anyone?

you can post on a sticky??? i didn't know that...

john
Old 02-03-2005, 10:10 PM
  #66  
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Default RE: 1/2A trainer anyone?

I'm getting the updates now.

I'm going to change the wing so that rather than a D tube, it has a 1/8" spar between the LE and the main spar; this is to simplify construction. Shear webs should be used.
Old 02-03-2005, 10:39 PM
  #67  
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Default RE: 1/2A trainer anyone?

Andrew --

The plans look fine. However, you might consider adding a main gear layout. There have been several questions regarding the main gear and how torsion gear should be installed. I think a main gear cross section might clear some of these up. Using nylon zip ties for gear retainers is pretty slick -- I don't think I have ever seen them used before, but it's a great idea.
Old 02-03-2005, 11:02 PM
  #68  
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Default RE: 1/2A trainer anyone?

I've added the layout for the gear. I used the nylon tie wraps on another plane and they worked great. Easier to install and hold better than anything else I've tried on small planes.
Old 02-04-2005, 08:28 AM
  #69  
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Default RE: 1/2A trainer anyone?

Would you consider leaving the d-tube plan up as an older revision or the like, for us D-tube fans?
I know it's probably silly, but I like the way d-tube wings look when covered compared to the 'Herr style' wing with the little top spar in between the leading edge and the main spar. Maybe i shrunk the covering wrong or something in the past, but the Herr style makes the wing have sort of flat places between the ribs where the covering wants to sag down but can't because of the little spar- in a sort of 'connect the dots' way. The airfoil shape turns into a sort of polyhedral between the ribs, and only at the ribs is the cross section really the shape of the rib, where the D-tube type has a nice smooth curved surface from the leading edge to the main spar at all points..

I'm about to cover another herr wing, so maybe I can manage to do better this time- it's probably just me. Maybe I need to 'sink' the little spar into the ribs further -the Herr Style is sure quicker to build.

I just realized that not all Herr engineering designs use the above mentioned little-spar-between-the-leading-edge-and-main wing method, so it's not right to call it the Herr method- the Herr mustang for example sheets that area..
The two herr planes I have are the star crusier and the cessna..
Old 02-04-2005, 11:11 AM
  #70  
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Default RE: 1/2A trainer anyone?

ORIGINAL: mclintock

--but this plan is free!

YES!!!Free is good.WAAAAYYYYYYY Good!!Good work Bipeflyer.
Old 02-04-2005, 11:19 AM
  #71  
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Default RE: 1/2A trainer anyone?

mclintock,

I don't like the way it looks either, thats why I usually do sheeted foam. I was just thinking of ease of building for the first time builder.
Old 02-14-2005, 04:13 PM
  #72  
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Default RE: 1/2A trainer anyone?

I am currently building this plane. I tried to upload a pic, but my connection must be too slow. I printed the plans on my HP printer. Then using straight edge and knife, cut on the lines and taped them together.

So far, I have about two hours into this plane. I have the fuse nearly completed. I will try to post a pic again later. Tomorrow I am going to try and build the wing and get some covering done.

I plan to use micro servos (aileron, elevator, and throttle), .049 norvel, and 2 oz tank.
Old 02-14-2005, 04:27 PM
  #73  
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Default RE: 1/2A trainer anyone?

Use software to resize/increase compression on the pic. A good .jpg file would be around 800x600 pixels and around 60k. Anything bigger is too big. Smaller would be better!

What's the weight of the fuse? Wing?
Old 02-15-2005, 12:44 PM
  #74  
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Default RE: 1/2A trainer anyone?

[ but the Herr style makes the wing have sort of flat places between the ribs where the covering wants to sag down but can't because of the little spar- in a sort of 'connect the dots' way. The airfoil shape turns into a sort of polyhedral between the ribs,]

Of no consequence in the application under discussion in this thread, but the prominence if the spars in the forward portion of the airfoil is actually beneficial in certain applications, acting as a turbulator.

jess
Old 02-18-2005, 11:27 AM
  #75  
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Default RE: 1/2A trainer anyone?

Here is a picture of my little Kadetlet. This picture was taken as I glued on the stab. You can see the plan glued to the fuse. That made it easy to cut out. The plane is now completed. I am going to turn it over to its owner today and hopefully (weather permitting) I can post a flight report.

The motor is a norvel 049 with throttle. I had to add nearly 6 oz of weight to the nose of this plane, and have really increased the wing loading. I would recommend to others that you either put a heavier engine on this plane, or extend the nose out some. I built it exactely per the plan (d-tube wing), and it was really tail heavy. A 15 would have made it balance properly, but would have shortened my flight times.

Does anyone have any comments about flying this plane with all of that nose weight? I believe the weight was about 28 oz.
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