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Depron Extra 300

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SwaziFlyer15/04/2015 15:41:32
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44 forum posts
28 photos

Hi Everyone, i have been following all the build logs i could find and have been plucking up the courage to post a build on the forum for a while as the build skills and fineshes i have seen are incredible. resources and mentors are a scares thing here in the country i live in and maybe only 10 RC pilots that fly here.

I decided I just dive in to a depron build and tackle the hurdles as they came. I chose the Extra 300 as I want something that I can expand my flying skills on.

I started on the wings and have built them in the traditional balsa style and have made a start on the fuselage now, any suggestions and advise is most welcome as this is a learning experience for me.

Wings 1.jpg

Sketchup.jpg

Fuselage 1.jpg

Matt

Dave Hopkin15/04/2015 15:59:39
3672 forum posts
294 photos

A good start...... looking forwards to see how this develops

Tony Bennett15/04/2015 18:25:10
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5080 forum posts
129 photos

what have you made the wing spars from sir.

looks a good start though.yes

SwaziFlyer15/04/2015 18:40:15
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44 forum posts
28 photos
Thank you. The wing spar is made out of depron with the trailing edge out of balsa. I want to sheet one side of the wing to see how rigid it will become. If it is still to flexible I will insert a dowel through the ribs to stiffen.
Tony Bennett15/04/2015 19:03:19
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5080 forum posts
129 photos

that will work sir.

SwaziFlyer16/04/2015 07:57:24
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44 forum posts
28 photos

Managed to get some building in last night, I have no idea how you all produce formers so quickly, I start with paper templates from the plan and tape them to the depron sheet and then cut them out, not sure of any other way at the moment.

fuselage 2.jpg

The reason the nose looks so long is that I have extended it all the way to the end of the cowl, I have two motor options, one with the motor in front of the mounting bracket and the other one with the motor behind, not sure if the second one has a long enough shaft to get through the firewall, will do some tests when I get there.

David Tayler16/04/2015 09:03:32
96 forum posts

Just a hint, rather than taping the templates to the depron,I use a prit stick to stick them on.Once cut out I then find it easy to just peel the paper off the Depron.There sems to be almost no residual glue left on the Depron.Congratulations on your blog. David

SwaziFlyer16/04/2015 09:12:28
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44 forum posts
28 photos

Thank you David i will give it a go.

Matt

SwaziFlyer16/04/2015 20:54:57
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44 forum posts
28 photos
Hi all, hoping to get an opinion. I have put the horizontal depron along the thrust line so I had a reference . If I place the battery on tray as per the plan I will have to make the access hatch on the bottom of the fuselage. If I put the battery on top it may be a squeeze, any suggestions or ideas.
Tony Bennett16/04/2015 21:34:56
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5080 forum posts
129 photos

cut a battery sized hole in the horizontal sheet and build a box hanging down, then fit a top hatch.

SwaziFlyer21/04/2015 07:33:16
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44 forum posts
28 photos

Morning All, been a bit of a busy weekend (Monday was a holiday here) so not much done, have started cutting out the engine mount and firewall out of light ply, the ply I have available is fairly thin so I’m not sure I will cut out lightening holes, nest to tackle how to secure the firewall to the fuselage.

engine mount cutouts.jpg

the reason for the hole in the firewall is i was testing motor mounting options.

Tony Bennett21/04/2015 08:12:15
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5080 forum posts
129 photos

lite ply gussets with triangle stock between them and the firewall.

SwaziFlyer21/04/2015 08:51:50
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44 forum posts
28 photos

sorry Tony please can you explain gussets to me. laugh and thank you for always giving feedback.

Tony Bennett21/04/2015 11:22:32
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5080 forum posts
129 photos

cut some triangle shaped bits of lite ply

glue one edge to the firewall, bracing it with some triangle stock as a wedge between the two surfaces and then glue the other flat side to the inside of the fuselage.

it's easier to do than describe.

SwaziFlyer22/04/2015 09:03:19
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44 forum posts
28 photos

Have added the firewall and dry fitted the motor mounts, still need to add some support, before I start cutting out the battery box I want to work on the elevator, then fit the pushrods and sheet the tail, will then go onto the wing supports so I can get a better idea of the CG.

firewall.jpg

Dave Hopkin22/04/2015 09:50:36
3672 forum posts
294 photos

2mm Depron is fine for the elevator sheeting if your doing both sides with a 3mm core to keep it thin - but it need some lateral stiffening - maybe a balsa LE and TE and a Balsa LE for the Elevator too (hinge support and in-flight stiffening) -

But its looking a very good and miles miles better than my first attempt at Depron

SwaziFlyer22/04/2015 15:24:54
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44 forum posts
28 photos
Thanks Dave. Been doing lots of research on your builds and many of the other amazing builds on here. Would 6 mm be strong enough or is it better to build up with balsa supports. Only have 3 mm and 6 mm depron.
Dave Hopkin22/04/2015 17:16:30
3672 forum posts
294 photos
Posted by SwaziFlyer on 22/04/2015 15:24:54:
Thanks Dave. Been doing lots of research on your builds and many of the other amazing builds on here. Would 6 mm be strong enough or is it better to build up with balsa supports. Only have 3 mm and 6 mm depron.

3mm will be fine for the tail, just means a bit more sanding to get a thinner LE and TE

I am not sure what the span of this model is, but unless its big I would have though 6mm for the LE (that will allow you to sand the profile into it - if its in the order of 36-48" I would have thought (with a fully skinned depron wing 3mm TE woul be fine

SwaziFlyer22/04/2015 17:39:17
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44 forum posts
28 photos
The plan uses 4mm balsa for the horizontal and vertical stab. I was thinking of using 6 mm sheet with balsa strip on the hinge points. The wing span is 1 metre I think it's around 39' I could use square balsa strips.
SwaziFlyer26/04/2015 11:15:58
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44 forum posts
28 photos

Made some progress, have put some balsa stiffeners on the hinge points of the rudder and the elevator, as i said before there are no model resources here where i live so i had to improvise with the control snakes, i had some electrical copper wire, i removed the copper and have used the insulating cover as my snakes, there is a little friction but i think that’s due to having some slight curves from not going 100% straight. need to do some sanding and fine tuning then onto the sheeting the turtle deck.

snakes.jpg

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