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Gary's Ballerina Build


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Thanks Paul,

Yes I'm very happy to have a 4 stroke to go in. I dont have a lot of experience with them so it will be good learning as well.

Regarding the space around the engine mount, I was thinking the same thing. The top sheeting around the top deck still has to go on and that will increase it by another 3/32 but still not alot of space in places. I can always trim a bit off the ends of the mount if I require but I think it should fine.

Gary

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Hi All,

I decided to give 3d printing a cowl a go. I thought the ballerina would be a good subject to try it on and it also solves the issue of the tight space around the top of the engine mount. this is what iv'e created so far

screenshot 2020-04-29 at 14.11.45.jpg

It should be possible to cut out the holes for the OS 40 FS to stick out before printing or i might just print the first to see how it comes out and fits then try getting fancy later. Anyone with any experience of this please jump in.

The other use is to use this as a mould for Vac forming then several can be made easily. You've got to love technology.....if it works

Gary

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It will be interesting to see how this turns out I know nothing about 3d printing so can't help you. Will the material you use for the cowl withstand the vibration and glow fuel ? I have seen a few bits and pieces produced by 3d printing but I think that they were all for electric models. Any chance of a video of your printer producing the cowl ?

Paul.

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Hi Paul,

The material used is either PETG or PLA to print these cowls. These are fairly hard plastic and vibration will be no issue as the parts are essentially melted together layer by layer. I don't know what effect glow fuel will have , if any, but there is only one way to find out!

The printer took approx 5 hours to produce the first trial cowl but i will try and take some photos to show its progress. It came out small but I forgot to take account of the sheet sides and skin as i took the initial measurements from F1. Nothing lost as there is always a few things i like to change after you get the first attempt in your hands.

I rounded off the bottom corners to make it less angular and bulged out the bottom to be more like the profile in the plan. I added a hole for the engine but this is just a rough estimate just now, i will get some measurements when the engine is back in to finalise things. I also cut some holes for screws

2.jpg

1.jpg

I'll give it a go and if it doesn't come out well then i can always go back to making it from balsa.

Gary

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It has been a slow couple of days for building, mounting the wing took a bit longer than i'd like and checking the horizontal stab seat was square with the wing.

I made a start on the fairings around the tail. I use technique below of cutting a replica of the fin and stab from scrap 1/4 sheet. This is the same size as the part that will be covered by the fairing

20200430_203024.jpg

Sorry for the upside down photo, i've given up fixing them! I put this piece onto the fuse where the tail will seat

20200430_203044.jpg

At this point you can use some balsa block to fill the gap. Me, being a traditional Scotsman, don't like using the more expensive block when you can fill it with all the scraps you end up with at this stage of a build.

20200430_203604.jpg

The scrap 1/4 sheet keeps everything stable and strong whilst you sand to shape and this is much easier than trying to do it with a fin and tailplane in the way. I like to use wood glue here instead of CA because there isn't a lot of surface contact without the actual tail surfaces being in and wood glue fills any gaps better and is not as brittle as CA.

Gary

Edited By Gary Clark 1 on 30/04/2020 22:53:05

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Thank you Mark, that is certainly a compliment coming from you!

I had thought that was the case but i take the photos in the garage then write this up later in the evening and i can't be bothered to go back out and take another. I just have to be more disciplined when i take them i guess!

Gary

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Thanks Ron, I need to try and be better taking them.

I've been working on the cowl recently after the first attempt was a little small. I changed the design a little and tried to cut the hole for the engine by measuring and guessing.....only 1 way to find out if it will work.

screenshot 2020-05-01 at 13.19.25.jpg

screenshot 2020-05-01 at 13.18.51.jpg

That was the updated attempt. I was tempted to try and measure where the needle vale hole would need to be but i figured that would be the single biggest achievement in modelling history if i managed to line that up on a cowl that didn't exist yet and one that i didn't even know if it would fit. So i didn't bother.

Here are some photos for you Paul. It shows the progress of the printer and how it build supports for areas that have an overhang. I've circled these areas and the holes for mounting screws

20200501_165545.jpg

20200501_185917.jpg

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So i took it out and tried it on for size

20200502_124811.jpg

20200502_124712.jpg

I think it looks quite good! It may be a little narrow still but i"ll mount it properly and see. The engine hole looks like its in the right place so i'll get them both on and see.

Gary

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Thank you Dan. I'm glad it is bringing you some enjoyment.

I haven't got too much done over the weekend but still got bits and bobs sorted. I got the wingtips done and the ailerons cut out so the wing is essentially complete. Just a final sand and fill any little dunts and it's on to covering

20200503_203026.jpg

The tips came out ok but i would recommend using a hard balsa here as the 1/16 sheet bends in a couple of directions and pulled it in certain places and made it a tad wavy but i think i've sorted it enough.

The 3d printed cowl is almost perfect. The hole for the engine is a little low so needs moved up and i think the top is a little bulged so needs smoothed out. I'm quite happy with it for a first go and i could probably modify it to be perfect but i reckon i'll just print another since this is an experiment to see how it works.

20200503_220614.jpg

20200503_220636.jpg

Gary

Edited By Gary Clark 1 on 03/05/2020 22:28:07

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Thanks Gents for the kind comments.

I have a question, what are people using for the trim around the edge of an open cockpit like this? I also need some for the 1/4 scale moth minor I am building on the side. I noticed you finished your ballerina off with this trim Peter?

Thanks in advance

Gary

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Hi Gary,

I trimmed my cockpit edge on the Ballerina with an opened up soft tube, like a fuel line tubing.

I covered that with crêpe tape and gave it a wash of acrylic paint to imitate some weathered leather.

1447_cockpitmaps01_900.jpg

1450_cockpit_rcme_900.jpg

There are many other methods of course.

Cheers

Chris

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Sorry for the lack of updated guys, i've been working but forgot to keep this updated.

I got the back end all finished and had a trial fit of the tail parts

20200506_190948.jpg

I made a couple of changes to the cowl and printed a new one. I have to say that i am very happy with the result! It will get a coat of build primer, a sand and then prime again before a coat of red to try and match the covering

20200506_191132.jpg

20200506_190815.jpg

No comments about my untidy workshop, i've tried to be tidy but it just doesn't work!! The fit of the cowl is pretty good i reckon. Peter, i'd be happy to supply them if anyone building the Ballerina is interested, the cut out for the engine is optional so would be perfect for electric as well.

I was in a 3d printing mood so i shrunk down a dash i had made for my moth minor and stuck it in

20200506_182207.jpg

I included a VOR so i can do some IFR....

I have the tail parts, ailerons and the underside of the wing all covered but still to add the red trim. I completed the mechanics of the ailerons so i will get the top covered tonight. I made a quick video of everything working if anyone wants to see. It's pretty much exactly as peter has on the plan but i used a collet in the middle to secure all the piano wire.

Aileron Video

I think she will be done in the next couple of days which makes it 3 weeks from start to finish.....very quick for my usual standards!

Gary

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That all looks great.The cowl is superb. The video of the aileron controls is also great and will be very helpful to builders of many of my designs.

Your workshop still looks far tidier than mine but then I do tend to workuntil I just cannot work anymore before I have to have a clear up.

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