Will this bell crank work on a foam wing?

[Paul Taylor]

http://www.brodak.com/shop_productdetail.php?ProductID=5569

 

[Wynn Robins]

yes, but you are better off with the phenolic ones are they are thinner...


to mount them with the post, make up bearing blocks out of a hardwood (pine works too)  and make them into a elongated diamond.  cut holes to match the diamond shapes in your cores.....glue the bellcrank post to the blocks.  When you assemble the wing, glue the blocks into the holes you made....make sure they are flush with the top of the foam.

When you sheet over the middle section, the blocks will glue to the sheeting also.....I have pics....,that would be easier

[Wynn Robins]

best pic I can get this shows the two blocks installed and the bellcrank mounted this is how they work

[Bill Little]

http://www.brodak.com/shop_productdetail.php?ProductID=5569

 

Hi Paul,

Those bellcranks were used many, many times by Windy U. in Foam wings.  Especially his Big Jim Hemi 60 planes.

Kinda overkill for 35 size panes.

Bill <><

Bill <><

[Paul Taylor]

What would you suggest from Brodaks site?

[Bill Little]

What would you suggest from Brodaks site?

Hi Paul,

For a standard 35-40 size airplane, the regular Brodak 4" "white" nylon bellcrank is way more than adequate.  I don't have a part number handy.

Bill <><

[Bill Little]

Many years ago when I was writing the Products Column in Stunt News, I published a test of various bellcranks which was conducted by Noel Drindak, I believe.  The Brodak, Sig, etc., and all were more than adequate in strength for our uses.

[Warren Wagner]

Paul,

Sure, that bellcrank will fit in a foam wing okay....see photo.  The photo is also one of Windy's bellcranks, but a step up in design, with forked cable mounting.  The support for the 1/8" diameter shaft will come from 1/8" ply plates which will be added after the wing is installing in the fuselage.

We could better offer a recommendation if we knew what you were building.   Please give us a few details.

Cheers.

Warren Wagner

[Andrew Borgogna]

Yes and here is yet another picture of how to install it.

[Paul Taylor]

Thanks Guys,
I am going to build a profile Cardinal. I got a foam wing from Crist.

Someone told me that they learned the patteren with this setup. Said it would fly like a Timex watch.
Takes a licking and keeps on ticking.
In search of a bell crank.
Paul

[Bill Little]

Thanks Guys,
I am going to build a profile Cardinal. I got a foam wing from Crist.

Someone told me that they learned the patteren with this setup. Said it would fly like a Timex watch.
Takes a licking and keeps on ticking.
In search of a bell crank.
Paul

Hi Paul,

The standard Brodak 4" BC will be more than adequate. 

The Profile Cardinal is a great flying profile.  Many I have seen were powered by LA 46 and fly great!

[Paul Taylor]

How would you mount a standard bell crank in a foam wing. The ones pictured seem to have a post that run from the top to the bottom of the wing.

[Andrew Borgogna]

I have actually extended the bellcrand pose on mine above and below the wing to allow the bellcrank to be anchored into the fuse.  In my mind this insures there will be no pull out during a pull test.  A foam wing is kind of like a case hardended bolt, hard on the outside and soft on the inside.  I never depend on the foam to anchor anything.
Andy

[Bill Little]

How would you mount a standard bell crank in a foam wing. The ones pictured seem to have a post that run from the top to the bottom of the wing.

An 1/8th" plywood scab on the top and bottom of the wing that the shaft goes through.  Notch out the fuselage so that the ply fits snug.  Epoxy all of it together.

[Mark Scarborough]

I think what you are after, in a normal bellcrank "kit" or setup, they provide a bolt to mount it to a ply plate, if you replace that bolt with a peice of appropriatly sized pianno wire and appropriate bushings you will have the "right" bellcrank for a foamer. just choose your poison as to the best mounting system. myself I use the half spar that holds the gear clips as a hardpoint for the pivot wire, transfers the load quite efrfectivly to the wing. a small 1/32  ply ring on top and bottom distribute the load to the sheeting.

[Wynn Robins]

Paul,

advice......buy the Brodak Strong Arm Bellcrank product number BH-391

that is all you will need.

I dont believe the cardinal is the best airplane out there to fly the pattern.....there is something about it that is not quite right.

HOWEVER....you can change the controls to make it work a LOT better...I have drawings and dimensions for changing them to make them work more linear if you want them

[Mark Scarborough]

I dont have one, but I have heard that the flaps on the profile are to large, seen it mentioned several times, perhaps changing the ratio of flaps to elevators would work also?

[Michael Boucher]

Has anyone had a bellcrank rip out of a foam wing?  Ever with the blocks in place, it don't seem like a lot holding it in place.

[Wynn Robins]

I have never seen that happen.....a lot of guys here fly with foam cores and htey aseem to hold up great.  you have to remember that these are glued to the core AND the top sheeting....this distributes the load from a single point........they are pretty tough..

[Bill Little]

I'm with Wynn.  I have yet to see a BC rip out of a foam wing. 

[john e. holliday]

Has anyone had a bellcrank rip out of a foam wing?  Ever with the blocks in place, it don't seem like a lot holding it in place.

On the very first Sig Mustang on the 10th flight the bellcrank mount came loose in the foam core.  They only showed the plywood glued to the bottom of the socket in the core.  I learned the hard way to put ply wood top and bottom.  Have pull tested planes to 50+ pounds.  DOC Holliday