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Fouga magister 1/4.5 moulded from scratch

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dirk tinck15/09/2020 22:38:26
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I will soon explain how a tail cone is made in the new moulds. No need to vacuum-bag tthe two halves as this is a simple shape and strong enough without adding to much weight.

The lay-up is 1 layer of 50gr

1 layer of 100gr

1 layer of 200gr

see you soon !

dirk tinck20/09/2020 22:33:41
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OK , back to the tail section.

As i have never made parts using the vacuum techniq ,i called for the help of my friend Ben,who has more experiance.

First of all, the moulds for the tail parts (rudders)were waxed several times and were given a coat of PVA.

Instead of using gelcoat , the inside of the moulds were painted with acryl spraycans. If all goes well , this should come out of the mould on top of the partsembarrassed.

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Next thing to do is get the fabric in together with epoxy. We're using 100gr fabric for the outside. A minimum of slow resin was used (155 min. worktime ).The ''overhang was carefully cut away with rounded scissors.Sorry , bad picture )

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next was getting the sandwich material ''airex'' in place. This was cut to fit the mould and covered with resin to let it soake before the lamination.

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following the airex ,is the second layer of fabric . this time we used 70gr fabric.

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The last layer is the ''peel-ply''. when removed ,this gives a rough surface ready to glue together.

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Next in line is a plastic perforated film .It lets the resin trough so it can be soaked up by the next layer,either paper towles or a special cloth made to soake-up resin (no pics , sorry)

Last thing to do is to put everything in a sealed plastic bag ,and let the vacuum pump suck all the air out

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You can clearly see the white cloth on top of all the rest. The green part is something we tryed out to get the fabric into tight corners. It's liquide silcones used for casting. We made up a corner piece up front.

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This is left 4-5 hours to dry and schould leave us with two halves for one rudder.

We used 0.650 bar to get the air out ,the pump stops and starts automatically to regulate the vacuum,credits to Ben who made this device himself !!

dirk tinck20/09/2020 22:53:40
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677 forum posts
964 photos

24 h later ...

Yes !! we have the parts to make a rudder !!

Normally the parts stay in the moulds until they are glued together but as these are test pieces ,we wanted to see the outsides !

It's time now to make the interior parts like ribs to support the joiner tube ,blocks to receive hinges etc...

When all that is ready ,we can put the parts back in the moulds and join the two halves !!

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Here you can see how the resin,together with the dissolved color is sucked trough the airex. (the airex is perforated )

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a lot of cleaning to do !!

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dirk tinck01/10/2020 22:52:48
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677 forum posts
964 photos

Hi all !

I've been busy making the interior parts for the rudders. Keeping an eye on the weight i opted for 1 1.5mm ply rib at the root ,a second one 3mm ply where the tube starts , nr 3 is a 3mm ply where the tube ends and another two 4mm balsa ribs.The carbon tube at the leading edge has two goals : 1 for strenght and 2 ,to hold the thickened resin in place when closing the moulds.The rest is a number of balsa blocks to support the anti-rotation pin ,hinge-pins . A little cross plate will serve to hold the rudders onto the fuse.Remember this is a trial version of the rudders and according to the weight test results ,next ones may have different parts inside.

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Next thing is another ''first'' for me : Making a epoxy tube with a sleeve .It's a piece of cloth in the form of a ''sleeve''.It's a great help for this task as you just have to slide it over the joiner you want to use and pull to crimp it around and add resin .To protect the carbon joiner i wrapped some plastic arround it first. When dry ,jou just slide it of : done .For the fisrst try i didn't trust it to do 1meter in one piece so i'm making two halves on one rod but it's so easy you can do even two meters in on piecewink 2!

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Next on the list is to fit it in the ply ribs later this week .Stay safe out there !

Danny Fenton01/10/2020 23:36:02
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9753 forum posts
4556 photos

Great to see the process

Cheers

Danny

dirk tinck02/10/2020 14:12:43
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677 forum posts
964 photos

Thanks for visiting Danny !Lots more to come!

alan p02/10/2020 15:13:53
298 forum posts
25 photos

Hi Dirk

You don't mention what material the cloth tube is made of. A interesting method to achieve a good fit on a wing joiner, as fit between tube and joiner is a bit of a lottery.yes Always willing to garner knowledge from my peers.

Alan p

Flyer02/10/2020 15:16:54
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636 forum posts
109 photos

Superb work Dirk, just shows the amount of work that goes into fully moulded models.

Excellent blogg. Keep up the good work.

Cheers

Ade

dirk tinck02/10/2020 18:48:14
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677 forum posts
964 photos

Hi, Alan P,

Sorry it was unclearembarrassed,

The tube i made is nothing but glass cloth,glass-fiber.The one i used was 136gr m².

It's a very easy and effective way to make the tube for wing joiners or in my case now ,rudder -fuse joiners.

If you worry that the tube might be to big (inner diameter)for the joiner they are made on , because of the plastic in between , i can assure you ,that is NOT the case. It is still a perfect fit !! If you hold the combo vertical , the tube does NOT slide off !teeth 2I just tryed it .The protective plastic is easy to pull out of the tube.

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If you want to try it , i recommend you look for a cloth tube close to the joiner diameter. You can stretch the tube but then the meshes get bigger

I purchase mine at the webshop of HP textiles , Schapen , Germany. Great service !!

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Hope this helps ! If not , shoot !!wink

dirk tinck02/10/2020 18:49:12
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677 forum posts
964 photos

Thanks Ade !! Keep safe !

Flyer03/10/2020 08:50:10
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636 forum posts
109 photos
Posted by alan p on 02/10/2020 15:13:53:

Hi Dirk

You don't mention what material the cloth tube is made of. A interesting method to achieve a good fit on a wing joiner, as fit between tube and joiner is a bit of a lottery.yes Always willing to garner knowledge from my peers.

Alan p

Found this in the 'tinternet thinggy Alan ,

www.ecfibreglasssupllies.co.uk/category/glassfibre-braid

Loads of interesting stuff there

Regards
Ade

alan p03/10/2020 09:18:06
298 forum posts
25 photos

Thankyou Dirk method explained perfectlyenlightened. Always watching with interest brilliant threadsmiley

Best regards

Alan p

dirk tinck06/10/2020 23:22:10
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677 forum posts
964 photos

Hi again !

The internal affairs are glued in together with the epoxy tube ,anti rotation pin ready to glue in and hinge support blocks in place.

Before i'm closing up the rudder i'm going to make a drawing so i can duplicate everything for the second one. You can see that the hole to put the joiner in is closed up ,this will be opened when the rudder is out of the mould. This hole must have a larger diameter to take the tube that's coming out of the fuse for about 5 cm. (wall thickness 2.5mm)This is necessary because in the fuse there is only +/- 5 cm room for a tube .That's not enough for a 50cm rudder !Future foto's will make this clear.

I also made the opening for the servo. I opted for a 15mm servo as there is not enough space for a standard one.I chose a SAVOX HV 1250 with 8kg torque. Any comments on that ??

The servo will be entirely hidden in the rudder so i have to open it up on the root-side to get access.So no servo hatch needed

All openings (tube and servo) will be taped to avoid glue getting in there.

The metal roundel is part of the system to bolt the rudder to the fuse.Later more on this ...

Fingers crossed !!

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The foam block at the end of the the tube is there to prevent the tube from sliding -in to deep.

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dirk tinck06/10/2020 23:41:42
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677 forum posts
964 photos

For those interested in the weight , i'm at 118 gr for the bottom-side and 61 gr for the cover.Plus some glue and the servo. to compaire :A foam rudder covered with veneer and glassed was 320gr. No servo either.

Danny Fenton07/10/2020 08:42:24
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9753 forum posts
4556 photos

Excellent information Dirk, will have to have a go at the joiner tubes, I especially like that technique.

Looking forward to your next post already smile p

Cheers

Danny

Danny Fenton07/10/2020 08:47:43
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9753 forum posts
4556 photos

I hope you don't mind me adding this Dirk?

In the UK I use East Coast Fibreglass for cloth supplies, they do a braid which looks very similar to the stuff Dirk is talking about.

Various sizes are available:

glass braid.jpg

Cheers

Danny

Danny Fenton07/10/2020 08:57:22
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9753 forum posts
4556 photos
Posted by Flyer on 03/10/2020 08:50:10:
Posted by alan p on 02/10/2020 15:13:53:

Hi Dirk

You don't mention what material the cloth tube is made of. A interesting method to achieve a good fit on a wing joiner, as fit between tube and joiner is a bit of a lottery.yes Always willing to garner knowledge from my peers.

Alan p

Found this in the 'tinternet thinggy Alan ,

www.ecfibreglasssupllies.co.uk/category/glassfibre-braid

Loads of interesting stuff there

Regards
Ade

Sorry Ade, didn't spot you had already found the braid.

Cheers

Danny

Flyer07/10/2020 09:01:55
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636 forum posts
109 photos
Posted by Danny Fenton on 07/10/2020 08:57:22:
Posted by Flyer on 03/10/2020 08:50:10:
Posted by alan p on 02/10/2020 15:13:53:

Hi Dirk

You don't mention what material the cloth tube is made of. A interesting method to achieve a good fit on a wing joiner, as fit between tube and joiner is a bit of a lottery.yes Always willing to garner knowledge from my peers.

Alan p

Found this in the 'tinternet thinggy Alan ,

www.ecfibreglasssupllies.co.uk/category/glassfibre-braid

Loads of interesting stuff there

Regards
Ade

Sorry Ade, didn't spot you had already found the braid.

Cheers

Danny

No problem Danny, I'd failed to post the link. More info the better!

Stay safe

Ade

dirk tinck09/10/2020 23:09:16
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677 forum posts
964 photos

No problem Danny , any info is welcome!

dirk tinck09/10/2020 23:57:32
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677 forum posts
964 photos

Welcome at the rudder works !

Before i close the rudder moulds , i'm doing the internals of the moving part of the rudder , while i can still see the position of the hinge blocks and other mesures.Note the horn is still oversized ,this will be corrected when i know the lenght i need.Better to big than...to small. The holes for the pushrods aren't drilled either but their position is marked on the hinge centerline

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I was thinking all day , how on earth am i going to get the horns in position after closing the two halves???. Then i had the ideaenlightened to glue the horn in while they're not joined yet. No problem but then i can't put them together anymoresad....unless i make an opening in the mould and the cover shellcheeky. This way i can use a horn that covers almost the hole whole width (eases my mind)and will be in thesame position for all following rudders .The opening in the mould can easely be filled with plasticine to make the shells.

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I also marked the position of the horn on the moulds by drilling a tiny mark just outside the parts.

almost ready to close everything up !wink

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