Leading and trailing edges .... how to form them.

[kc]

There is an old trick with kits  - draw around each kit component onto paper noting thickness and material.   Then if you do really make a mess of construction you can replace any component and start again.   And of course you can replace any crash damaged item too.    But you really need to do this BEFORE starting construction!

[toto]

Thanks KC,

 

It appears that there ie many a way to skin a rabbit.  and everyone's input is welcome. It just shows how everyone develops their own successful formula as they progress in the hobby.

 

I have a few posts to try and regurgitate as I read back through them. All helpful stuff.

 

Toto

[john stones 1 - Moderator]

https://permagrit.com/

[fly boy3]

I have always used tiny balsa plane and sandpaper glues to a length of wood. I agree what has been said using these tools. Another tip is to have 3 lines in stead of one then you can see progress as you go along. Also keeping  an eye on profile shape. Give it a go, you will surprise yourself.

[Nigel R]

As might be becoming clear, this is mainly a practice makes perfect type skill... don't worry about mistakes, it's just wood - and can be fixed or replaced if things go wrong. 

[Peter Miller]

The best tool that I have used for leading edges and the Vee on the leading edge of control surfaces is the "Great Planes" sanding block. Two radii and a Vee shape.

Unfortunately I can't find a supplier these days

[toto]

That tool looks ideal. I'm amazed it's not all over the internet from various suppliers.

 

I'll do a search myself and see what come up.

 

Thanks for the lead.

 

Toto

[Peter Miller]

I bought mine donkeys years ago from the USA. Lookd a little while ago but couldn't find one but I didn't search too hard.Hope you can fine a supply 

[Engine Doctor]

On 14/04/2023 at 19:30, kc said:

There is an old trick with kits  - draw around each kit component onto paper noting thickness and material.   Then if you do really make a mess of construction you can replace any component and start again.   And of course you can replace any crash damaged item too.    But you really need to do this BEFORE starting construction!

That was common practice by some builders some time ago. We have two members who wanted the same plane so they split the cost and bought a kit between themat a show to try and get it even cheaper . Tight wads comes to mind 😉 . Then the arguments started over who got the kit parts and who got the copy ! Never did find out who won 😄

[Martin Harris - Moderator]

On 14/04/2023 at 19:30, kc said:

There is an old trick with kits  - draw around each kit component onto paper noting thickness and material.   Then if you do really make a mess of construction you can replace any component and start again.   And of course you can replace any crash damaged item too.    But you really need to do this BEFORE starting construction!

You can also retain the waste material once ribs, formers etc. have been removed from pre-cut sheets. Perfect outlines and material references. 

[Phil Green]

My Dad was a carpenter by trade, a proper one making ornate furniture etc, and he had a heavy metal plate with various sized round holes with sharp edges, used for making dowels. He'd cut square section very slightly oversize and tap it through the plate with a mallet.  He had a toolmaker pal make a similar plate with various sized  LE shaped holes and he regularly supplied SSA clubmates with spars and his 'preformed' leading edge strips.  I was only a kid and my memory is poor but but I dont think it was as perfectly formed as the stuff you buy.   For TE he made a diagonal-cutting jig and he had a special circular-saw blade which had a 'planing tooth' between maybe every dozen fine teeth.  Hand-planing TE with an RB10 didnt work, it would always curl.  I remember building several sharkfaces with his LE & TE, most were of necessity free-flight at the time, 'unguided missiles!"

 

 

 

[John Lee]

A chap in the USA is selling 3d printed contour sanding blocks. Should be relatively easy to reproduce.

[robert chamberlain]

Cleaning up the shop is part of the job and the sanding dust is the messiest.  What I have done is take one of those 20 inch square window fans and taped a 20" furnace filter to one side. The balsa piece has me on one side sanding, and the fan on the other sucking the air born balsa dust into the filter. Not too fast a fan speed or you will push the dust right through,---- and put the filter facing you. Good luck.    Bob C

[Basil]

On 26/04/2023 at 08:35, Peter Miller said:

The best tool that I have used for leading edges and the Vee on the leading edge of control surfaces is the "Great Planes" sanding block. Two radii and a Vee shape.

Unfortunately I can't find a supplier these days

Ron, there you go , there must be a demand for such a product, perhaps as separates in a different form perhaps. You can put me down for one.

Bas

[leccyflyer]

I have the Permagrit semi circular section leading edge sander and using it for the first time in ages the other day found it still worked fine, with a rocking motion converting the squared off rather angular leading edge stock to a nice conformance to the airfoil section. I do like the idea of those 3D printed items though - you could have a selection of them for different and consistently replicable leading edge sections.

[Cuban8]

Carl Goldberg kits came with a set of die cut shaping tools that you put together and attached sandpaper to. Only simple bits of equipment  that were intended to last for the build of the model - but I still have the leading edge forming tools from my Chippy and Anniversary Cub kits after 30 years and stiill use them from time to time. Very easy to make something similar I'd have thought. Worth making up profile templates from the plan to check progress no matter what tools one uses. Mk1 eyeball is only accurate to a point.

Permagrits (I have two very nice sets) are excellent but expensive for those on a budget, but very good tools can still be made up for pennies from scrap materials - and providing one uses good quality abrasive paper of the non-clog type, come a close second. May well be better alternatives, but I found that Garnet and/or Aluminium oxide  papers work very well.

 

 

Edited June 28, 2023 by Cuban8