Hey everyone!

I am putting together an ESM FW-190 71' warbird. Thread

I don't plan to use the included CA Hinges for the ailerons. I have some Robart 1/8th Hinges Link I saw that robart carries 3/16th hinges as well Link

It looks like Robart only recommends the 1/8th for up to 90 size planes and the 3/16th is for 1.2 and up. I plan to put a OS 33 in this plane. I am curious if the 3/16th are really necessary since this is not a 3D Plane.

Any help would be awesome.

Thanks!

I'd go with the 3/16 on one that size

>>It looks like Robart only recommends the 1/8th for up to 90 size planes and the 3/16th is for 1.2 and up. I plan to put a OS 33 in this plane. I am curious if the 3/16th are really necessary since this is not a 3D Plane.

Any help would be awesome.<<

I presume you meant 71" and not feet.

The size of the hinge will depend on the thickness of your control surfaces and the number of hinges you plan to use.

I just finished putting together an Hangar 9 30cc Ultra stick and I am using the 1/8" diameter hinge point instead of the 3/16". Personally I prefer to use a higher number of smaller diameter hinge points over lower number of the larger ones.

The reason is that I felt there are more wood to bond to the the smaller hinges and I make up for it by using more.

OTOH I also built a Byron original 1/3 scale Pitts. On that plane I used 3/16" diameter since the control surfaces were thicker.

No real rhyme or reasons just personal preference.

Typically a Robart hinge point needs a bit more than just a straight diameter hole. You need to enlarge the entry point a little bit to let the tapered portion of the hinger to sink in deeper. It depends on how you plan to create that tapered pocket. I use a conical bit on a Dremel and sometimes that can take off too much of the wood for me to feel really secure. So I opted for the 1/8" version.

The choice is yours.

What's the point of a tapered pocket? the hinges aren't tapered,, I've used these things on many planes,,, a straight hole always worked just fine

Originally Posted by scale_only

What's the point of a tapered pocket? the hinges aren't tapered,, I've used these things on many planes,,, a straight hole always worked just fine

Not so much on the 3/16" but the 1/8" sure looks tapered to me.

aaaah,, I see what you're saying,, I usually just square up the end of the hole with an hobby knife

No, not tapered. The hole is the size of the ribs on the hinge. The area between the ribs is designed to hold glue. I've never done anything to taper them anyway...

I do agree on the number of hinges having an influence on what size you use. A 70" 3D plane I just did this on uses the small hinges (or more likely, a Chinese knock off), but there's 6 of them on each aileron.

Lots of ways to install Robart hinge points. The idea is to put the pivot points where we want them and the control surfaces move smoothly.
The methods of installation varies with different people and planes. The leading edges of the control surfaces are also a factor. The main factor that determines whether I use the 1/8" or 3/16" (maybe even 1/16" for the smaller models) is the thickness of the material to install the hinges. If the thickness is 1/4" then the 3/16" will be too large. If the thickness is 3/8", the 3/16" hinges will be just fine.

If I did the 1/8th I would do 3 hinges per aileron.

Originally Posted by colemn615

If I did the 1/8th I would do 3 hinges per aileron.

You may consider using more. Depending on the length of the aileron. For a 71" wing span plane it probably has barn door ailerons on the outboard. You are talking about maybe 12" to 16" long ailerons. I personally will use 4 to 5 each side.

Originally Posted by SeismicCWave

You may consider using more. Depending on the length of the aileron. For a 71" wing span plane it probably has barn door ailerons on the outboard. You are talking about maybe 12" to 16" long ailerons. I personally will use 4 to 5 each side.

Holy crap really? I haven't measured the ailerons but they are close to scale for the plane.

Originally Posted by colemn615

Holy crap really? I haven't measured the ailerons but they are close to scale for the plane.

No matter how long the ailerons are really. As long as you are using a 33 cc engine and the wing has 71" span you need a few more hinges besides 3. The Robart hinge points are very nice hinges and easy to install but there is one minor issue with them. That is the side movement. Since they are so skinny the hinges will let the control surface move from side to side a bit more than flat hinges.

I cannot remember any planes that I use only 3 hinges on the ailerons anymore. I use at least 4 and most of the time 5 on each in just about all my planes. Of course a lot more on strip ailerons.

I will feel around and see how much wood there is in there. I don't think there is places to have more than 3 of the hinges.

Also I am curious about the Dubro Heavy Duty Hinges. Link

Originally Posted by colemn615

I will feel around and see how much wood there is in there. I don't think there is places to have more than 3 of the hinges.

Also I am curious about the Dubro Heavy Duty Hinges. Link

If you are only going to use three hinges those Dubro heavy duty flat hinges may be better since you get a bit more lateral stability. If you can fit four of those flat hinges on the ailerons by all means do it otherwise 3 flat hinges will still be better than 3 hinge points. I just checked my Hangar 9 Ultra Stick ailerons. I used 5 of the 1/8" Robart hinge points on each aileron. To me that's just barely enough.

Wow so the flat hinges are stronger than the Robart Hinges? Could you further explain why.

Sorry this has got my curiosity peaked.