Valdez stol ;flap hinges

[Basil]

I wonder if some one will help me with some suggestions re flap hinges. I have now made a couple of builds since I started .During lock down I started the Li'l Cub build as a challenge. the idea was to widen my experience, how ever after some trails with the flaps/elevators , I decided that it was best to temporally suspend the build, I have now gone back to it and referred to the Valdez Stoll record breaker post ( Build of the cub). I have decided to use the more simpler hinge version as shown on page 3 of the post. The hinges shown ore 3D printed. I have been looking for similar hinges on line but most are labeled as door/hatch hinges. Can some one suggest a hinge  that is currently available .  that I can use please.

Thanks in advance, as I added similar to the Valdez build but did not get any replies. old model I suppose.

Bas

[Peter Miller]

Right!  I hate to admit it but I cannot remember what I used and can't find the old text etc.

How ever I would suggest this.

Add small blocks of balsa in front of the rear spar/TE of actual wing and also  behind the flap LE. If you have already sheeted the flaps small square holes can be cut in the lower skin and balsa blocks inserted.

 

You can then use Robart hinges drilled into the blocks. https://www.slecuk.com/robart-hinges-hinge-point Use the small ones.

The actual pivot point should be right in the join line when the flaps are in the fully up position.

You could use three per flap.  I hope this helps.

[Basil]

Hello Peter, the text/ picture I refer to(3D printed hinges) in on pge 2/3 of Valtez stol record breaking. Shown, not by you though, is a small hinge , off set. This makes it nice and simple. I have never used robarts , so especially as they are not in the centre, am very apprehensive. Is there a longditudal 'Tape/plastic strip, like mylar that folds in halve, (Possible covering problems of inter layed adhesion.is self adhesive . If I where to use an offset hinge would the gap created work , or does the flap be in almost contact with the wing to work? Over to to you if you have any further comment, If not thanks for a good model and for always being willing to help.

Bas

[Peter Miller]

Looked at in side view the Robart hinges would be "V" shaped. That would not be a problem with them.

 

If you are happy with the one that you mention by all means use it.

 

Quite simply the flap works by deflecting the airflow downwards so a gap would not have a lot of effect. A some flaps are even slotted to allow air to flow over them and down the rear face.

 

I have to confess that I have looked at the plans and the hinges are not shown.I do not have my original text or the actual article and these days my memory resembles a rather worn out sieve.

 

Sorry, senility is galloping in.

 

Peter

[Basil]

Peter, thanks for your comments.I have never used brobart hinges and dont in the least feel at ease installing them.The idea of the build,  to include flaps was to stretch my capabilities , it has done that, at least.I am trying to source some hinges at the moment but is not proving  good.

.Your mind must be many notches better than  mine.The hinge system is not shown on the drawing, I have searched the posts but cant find any reference other than that I mentioned. If that person that made the hinges would not mind making me a set I would obviously make suitable recompence. Once again you have come to my rescue, many thanks

Bas

[Peter Miller]

Installing Robart hinges is pretty easy. You just drill matching holes in the control surface and wing with a slightly smaller drill. The hardest part is making sure that they line up. Very carefully apply oil to the actual pivot to prevent glue going into the hinge.  Then apply glue into the holes (PVA or similar) and on the hinge pins and then just slide them together.

[Caveman]

Basil, I think these are what you're looking for

 

Multiplex MPX702010 - Multiplex Offset Hinges Funcub Set Of 6 702010 | Multiplex Spares | Wheelspin Models

 

They are standard on the Multiplex Funcub

 

 

 

They are simply super-glued to the foam but it would be easy to drill a few holes and screw them on.

 

They're a bit pricey but do the job properly

 

GDB

 

 

[Peter Miller]

Those look pretty good too.

[Basil]

Thanks to you all.

Caveman, is using adhesive alone strong enough, Cub is 53" span ?.

Peter, thanks again, as always you respond.

I will ponder the comments and try some arrangements on some dummy parts, might even try brobart hinges, Peter. Nothing ventured nothing gained, after all I did it to gain experience.

Bas

[Peter Miller]

Personally I  feel that the ROBART hinges would be the best as they do work well and the joints are really "mechanical" rather than just adhesive on a surface. i.e Sunk into drilled holes.

[Ron Gray]

I’ve used Robarts for flap hinges on quite a few models, here is the way that I retro fitted flaps to my Sig Rascal

 

 

 

[Peter Miller]

Exactly what I had in mind!!

[Tim C]

These are the 3d printed versions I used on my cub, there are based on the Fun Cub mpx version, If any one wants the stl files to print there own please message me.  the use and M2 hex bolt and nut as the hinge.

[Tim C]

Another picture

[Peter Miller]

Ah Yes! Screws.  I really like mechanical fastenings

[Basil]

Thanks to you all.

Caveman, is using adhesive alone strong enough, Cub is 53" span ?.

Peter, thanks again, as always you respond.

I will ponder the comments and try some arrangements on some dummy parts, might even try brobart hinges, Peter. Nothing ventured nothing gained, after all I did it to gain experience.

Bas

[Basil]

Thanks Ron, thats what I needed was to see exactly where the hinge starts/finished. I was thinking of a jig but was at a loss. Has given me something to aim for.

Bas

[Peter Miller]

the Cub is slow flying and not highly stressed. Just a comment

[Caveman]

Basil, as I commented before you could always drill some holes in the Multiplex hinges and secure with screw and/or nuts.

 

I do, however, like Ron's use of Robart's hinges which give a neat and sturdy finish.

 

GDB

[Basil]

Caveman, yes they look smart,its just achieving it. I am messing about with a jig as that must be the way for consistent results, It a case of keeping at it.!!!!!!

By the way is adhesive secured horns/ hinges ok on a model like this?

Bas

[Caveman]

The Multiplex horns are OK when stuck (cyano(super)glue) to Epalor of which the Funcub is made.

 

I can't see why they wouldn't stick to balsa just as well, but, if it was me I'd screw them on as well!!

 

GDB

[Basil]

Many thanks.Bas

[Basil]

Thanks to you all that gave me the want and how to try Brobart hinges. Made myself a jig for drilling flaps. After much messing etc made some dummy parts, then proceeded  to real thing. Fitted 3 in each flap, functions( I think, on the ground pre covering,)looks as per photos here on the forum. For Aielerons/elevator it but will  need another jig, but a bit more complicated as the position will be in the centre this time. If there are any suggestions on this subject I would be grateful for any advise.   Thank you fellow members for the incentive and info etc.

Bas

[Peter Miller]

Robart make a special tool for the job. Ripmax stock it  but you can make a similar thing easily

http://resources.ripmax.com/product_images/5/f/f-rb319_5.jpg

Part No: F-RB319

Robart Hinge Point Drill Jig (Each)

The hinge point drill jig guides the drill when making holes for hinge points. Adjustable for all control surfaces, it's made of hardened steel and incorporates removable drill bushes for...

Click here for more information

 

Price: £12.99

[Ron Gray]

Just make yourself one from a strip of wood with a hole in the dead centre plus 2 pins (bolts) at either end. You hold the tool on the TE and rotate it until the pins are against the top and bottom surface of the TE, the centre drilling hole will then be on the C/L for the hinge.