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Mar 25, 2017, 01:33 PM
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Build Log

Scratch build 1/12 LF-109 Pionyr glider started. Only my second glider project ever.


Well guys, as I started in my previous thread on the 1/12 SG-38 which I finished, I started my LF-109 Pionyr in 1/12 scale 44+" (1120mm). Yes the spelling Pionyr is right. That is the Czech spelling. I am vigorously working on the CAD drawing. The fuselage is almost finished and I will post a picture or a small PDF in the future. in the near future. Because the printer I have access to is only capable of 11x17 format, every couple of working days I print out a copy and tape it together to give me an idea in full building scale. Than I go back and make changes and continue some more. I think that I am far enough now to start framing up the aft fuselage. This can be built on the building board. For the front it will have to be removed and built onto the built aft fuse. Even though the wing here is considerably larger than the SG-38, I think I might cheat again and add one rib-bay to each wing for about an extra 10in.sq of wing area. This would bring me to about 247sq.in. of wing, vice the 187 on the SG-38. If anyone has any opinions, let me know I have not gotten too far on the wing and that would be a change easily made. Otherwise everything else in surfaces will be 5% larger. So let me know what you think.
I am not going to install the spoilers and I am not going to use the traditional bulkhead sections which have been so common on other plans and models of this aircraft. I am going to pretty much follow the scale superstructure format but not with round but square Bass, Spruce and Balsa. There is a modeler on the web who has built a very large model in this manor and I really like it and it should prove for a more concise build and shape. Because everything will build onto the straight longerons instead of relying on the bulkheads to give it shape.
I am also thinking that if I like this model, I will than double the size to 1/6 scale to about 88-1/2" (2244mm) span in that scale.. And No I will not add any wing area to that scale, no matter what. What I like about this kind of construction, is that is the old traditional stick-n-fabric construction with very little sheeting if any at all on this particular model.
Last edited by Otakar; Mar 25, 2017 at 02:07 PM.
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Mar 25, 2017, 02:22 PM
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I did forget to mention, that I did a lot of research on available plans for this model. There are actually a few of them out there. at minimum, three. The oldest is a plan from a Czech magazine "Modelar" this is a 1/6 scale plan. All the other plans out there are pirated directly from this plan. All the components are exactly the same just shifted on the page. These pirated copies are from French and German origins. When I show my plan, it will immediately be noticed that the construction is completely different and new. The only thing that stays the same is the shape of the aircraft, since it is a scale model. here is the model which I will try to emulate in construction and this is because it is mostly scale construction. The wing obviously will not be so intricate. It will be more to standard construction with either full ribs from 1/32 balsa or two spars with ribs curved over them. I have not yet decided on that .
http://dadin.rajce.idnes.cz/LF_109_Pionyr/
Mar 25, 2017, 02:25 PM
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Here is another, but different (build) link to the same model.
http://www.mikac.cz/sketchup-model-pionyr.html
Mar 25, 2017, 03:21 PM
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Here a couple of snapshots of my plan. The fuselage part at least. I taped together the 11x17 pages . This is at least good enough to start framing up the aft fuselage. The fuselage, as seen here is 22.5" long (without rudder, which will add another 3"). This will make the model 4.5" longer than my finished SG-38
Last edited by Otakar; Apr 10, 2017 at 07:58 AM.
Mar 30, 2017, 06:59 PM
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I am continuing promptly with the CAD drawing while I am building the model and also having some laser cut parts made. The only parts requiring cutting by laser will be the wing ribs. Here is my progress so far. Up to this point, 95% of the structure is Spruce. Also about 95% of the cement used is Ambrulos Nitrocellulose cement. Only the side longerons are attached with UV cure CA glue. Loctite 4311. This is because I am using it as a fillet.
Apr 01, 2017, 08:40 PM
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Started on the sub assemblies for the nose section. Floorboard and cockpit frame. When they are dry, I will mate the two and start the front nose frame-up.
Last edited by Otakar; Apr 02, 2017 at 06:22 PM.
Apr 02, 2017, 06:20 PM
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Got a bit farther on the fuse for this project this weekend. I got as far as I got with my CAD design. This week I will hopefully finish the CAD on the fuse and finish the fuse frame-up completely next weekend. I also finished the CAD for the horizontal tail section and hope to work on and finish during the week. Here are some more pictures of the progress.
Enjoy
Last edited by Otakar; Apr 02, 2017 at 06:42 PM.
Apr 02, 2017, 06:26 PM
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A few more of the mostly framed up fuselage. Almost all the stick construction so far is Bass and Spruce. The floorboard and aft cockpit aft wall are some of the few balsa pieces on this structure so far. As you may notice, if you have seen any of the plans available out there, there are no actual bulkheads on this model of mine. Same as in the real aircraft. I am trying to keep the structure geometry as close to scale as possible. With the major exception, that the real aircraft was welded steel tube and mine is square 3/32 with the cross-member stiffeners being 1/16. There are a few extra internal braces in the area where I joined the aft fuse to the cockpit bucket. I also added the two extra nose braces. If I most likely place the receiver battery in there, the extra strength wont hurt. Once again, ALL of this nose structure has been assembled with Nitrocellulose Ambrulose cement. I am shocked at how extremely rigid this structure is. I know that in the future I will really enjoy building this in model in 1/6 scale.
Last edited by Otakar; Apr 02, 2017 at 07:08 PM.
Apr 02, 2017, 07:51 PM
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I would like to mention that I am having a member here laser cut the wing ribs for me for this project. Small price to pay. It is costing me about ten bucks per set and I ordered enough to make three sets. Just in-case.
Apr 08, 2017, 07:26 PM
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I have done a bit more work on this and decided to enlarge the plan to 2" scale also. This will be 2.24M (88"). I do work on the CAD drawing every day and hope to finish it in a month or so. It seams like there is a laser cutter interested in producing it as a kit in the 2" scale. I will post more pictures of my building progress this weekend. I am also taking some days off from work next week and plan on getting along on some major building.
Apr 09, 2017, 08:26 AM
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Following with interest.
Apr 09, 2017, 12:05 PM
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I am happy to see that this has at-least one fan.
Apr 09, 2017, 12:25 PM
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I'm watching. Did you get the ribs yet?
Apr 09, 2017, 03:55 PM
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Matter of fact, I did, Thank you. They are fantastic. This gave me the opportunity to do some centersection construction. I will post pictures today. I am still building. I'm just taking a brake from the fumes of the Cement and Dope. It is my birthday on Wednesday so I decided to take three vacation days starting Wednesday and spend five days building. It will also give me the opportunity to finish the wing design tomorrow and Tuesday so I can have the print to build on for the rest of the week. I also ordered some thin PC to form the canopy from McMaster-Carr and also light weight Aluminum wire for the canopy frame.
Apr 09, 2017, 05:47 PM
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Interersting!


Hi:
I am amazed at how similar your plans and my LF-109 plans are. The three fuse views on one sheet are identical............. WOW
For my three versions: 1/5, 1/4 and 1/3 scale, I just had my print shop change the scale on the Xerox machine and I re worded the dimensions on the two.

I have a 101" version hanging in my shop.

Yea, I know scale plans should be alike, but model former placement is really custom.

Good luck with the itty bitty critter

cheers
Jim


Quote:
Originally Posted by Otakar
Here a couple of snapshots of my plan. The fuselage part at least. I taped together the 11x17 pages . This is at least good enough to start framing up the aft fuselage. The fuselage, as seen here is 22.5" long (without rudder, which will add another 3"). This will make the model 4.5" longer than my finished SG-38


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