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Author Topic: buttons and bellcranks  (Read 1228 times)

Offline Graham Collins

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buttons and bellcranks
« on: January 05, 2008, 05:29:57 PM »
I understand the principles of bellcranks with buttons for line connection but I have never used or made one before.

So, what material to make a bellcrank for 1/2a proto or mouse racer?  Aluminium (6061-T6 or ?) or steel? what material to make the buttons out of? Brass? steel? Minimum dimensions for making loops in the lines are in the rule book, how much bigger is the button made?

Same questions for a .15 size racer or .21 size proto?

Any online resource with details or description (other than the AMA rule book)?

Thanks,

cheers, Graham
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Offline Joey Mathison 9806

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Re: buttons and bellcranks
« Reply #1 on: January 06, 2008, 07:25:48 AM »
check with dave mark
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200 mph man ama#9806 joey mathison

Offline don Burke

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Re: buttons and bellcranks
« Reply #2 on: January 06, 2008, 11:08:03 AM »
Darrell Albert has some nice button ones for 1/2A.  Used to be Kustom Kraftsmanship, lots of 1/2A and other stuff.

Darrel might respond to this, or e-mail me and I'll send you his address.

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don Burke AMA 843
Menifee, CA

Offline Dave Hull

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Re: buttons and bellcranks
« Reply #3 on: January 18, 2008, 01:18:16 PM »
Graham,
I've been making Mouse Race and 1/2A proto bellcranks out of 6061-T6 stock .032" thick. I use a standard AN470-AD3 rivet for the post or button. Use a double loop on the lines since there is no pulley, per AMA rules. I would have to check my notes, but I think I make the loops 5/8" long, and the diameter is about half the difference between the rivet shank diameter and the rivet head diameter. When you set the rivets, put a small spacer under the manufactured head while you set the shop head. You will probably have to cut the rivets to get the right length, and then I file the shop heads to eliminate any excess. No failures or issues to date. Sorry I don't know how to attach a photo.

You would have to beef this up considerably for a .15 sized racer or speed plane. On .15-.40 size  racers I have been using the Fox 2" bellcrank in stock condition.

Dave "McSlow" Hull


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Offline Scott Jenkins

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Re: buttons and bellcranks
« Reply #4 on: January 18, 2008, 03:04:28 PM »
To all,

I have made a few bellcranks in the past and here is my latest offering it can be used with either buttons or a straight line hookup.
These bellcranks are CNC machined out of either G10 2 mm thick or carbon cloth plate. The first production run will be done in about 2 weeks. They are setup to be used with either a perfect style hub or a fox pivot hub. The prototype was pulled tested and has passed at 150 lbs in tensile pull.  These are as strong as any on the market today. The price for a bare bones bellcrank is $3.00.
Fully equipped with buttons made to your wire size and brass pivot and washer with a 6-32 Stainless steel button head screw $6.00. I also have a 2" Fox style bellcrank available too that will exceed the 150 lb pull test.

Scott
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Scott Jenkins
AMA 43122
FAI F2C VOLUME 2 SECTION 4, 4.3.7
m) During the refuelling and the restart of the motor, and until the time when he releases the model aircraft, the mechanic must keep the model aircraft in contact with the ground by at least one point and with the centre line outside the flight circle. During that time the pilot must be crouching or sitting inside the centre circle. He keeps one hand on the ground and his handle and his lines as close to the ground as defined by the F2C panel of judges until the model aircraft starts again.

Offline Graham Collins

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Re: buttons and bellcranks
« Reply #5 on: January 20, 2008, 07:20:15 PM »
Scott, Dave, Don, and Joey,

thanks for all the info. I have enough now to get done what I needed.

cheers, Graham

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