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Building Tips and technical articles. => Building techniques => Topic started by: Kirm Dog on September 13, 2006, 07:23:11 AM
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I have plans for a "Francherized Twister" and the plans show a 3" bellcrank. I was wondering if anybody has tried a larger BC? The plans show that there isn't much room to have a larger one but it looks like a 3.5" would fit. Would this be much of an improvement or should I just build according to the plans? ???
Don "Kirm Dog" Kirmess
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Don,
If you have a 3 1/2" BC, go ahead and put it in there. Increase the horn height, also. This will give some help in slowing down the controls, and less stick force needed in the wind.
I do believe you can get a 4" in there witrh some minor alterations if you wanted to.
You can always increase line spacing at the handle for more response, if needed.
Of course, thousands of them have flown great with 3" BCs! y1 n~
Bill <><
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A 3" bellcrank will be fine, it's a fairly small light airplane and you won't really need the leverage advantage of a larger bellcrank. I have been flying the twistMaster for 8 years with a 3 inch bellcrank and it's less work to fly than anything else I have.
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Thanks for the quick responce guys! I have a 3.5" BC and a few 4" BC laying around and was hoping I could use them instead of ordering a 3". This was a question more out of convenience than anything else. It looks like if I used the 4" that I would have some major work relocating it so I might just order a 3" or try the 3.5 unless someone has a quick fix for using the 4". The 4" looks like it would have to be moved back towards the flaps to gain room and I'm thinking this is a MAJOR NO NO! >:D The only other way to use the 4" BC that I can see is to hog out the inside of the leading edge but I don't know what that will do to the strenght of the wing.
Oh well, half the fun of this hobby is opening up boxes that can in the mail with things you have ordered.
Don
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Don,
I think I have a new SIG 3" nylon bellcrank that I don't need. You can have it for the ungodly sum of $FREE :o if you're willing to wait until I see you this Saturday at the field (weather permitting).
Dennis
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Thanks Dennis.
I think I will go to the fields on Saturday rain or shine( I only live a few miles away). I want to see if it's true that Fred really goes home at the end of the day or does he sleep in his car overnight waiting for daylight.
Don
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Thanks for the quick responce guys! I have a 3.5" BC and a few 4" BC laying around and was hoping I could use them instead of ordering a 3". This was a question more out of convenience than anything else. It looks like if I used the 4" that I would have some major work relocating it so I might just order a 3" or try the 3.5 unless someone has a quick fix for using the 4". The 4" looks like it would have to be moved back towards the flaps to gain room and I'm thinking this is a MAJOR NO NO! >:D The only other way to use the 4" BC that I can see is to hog out the inside of the leading edge but I don't know what that will do to the strenght of the wing.
Oh well, half the fun of this hobby is opening up boxes that can in the mail with things you have ordered.
Don
Hi Don,
You should not have any problems moving the mounting point back 1/2" to get the 4" BC in there. The 3 1/2" will work great, too.
Bill <><
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Hi Don,
You should not have any problems moving the mounting point back 1/2" to get the 4" BC in there. The 3 1/2" will work great, too.
Bill <><
[/quote
Very true but sometimes creating the new path for the lead outs can be more of a pain in the neck than relocating the crank. y1 **)]
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Hi Tom,
That is true. ;D
Since the rear lead out is the only one that needs a *little* more opening (the front one will be unchanged), I take the sanding drum in the Dremel and work on the 4 or 6 ribs, or so, that I will use from the BC out towards the tip. The Lead outs will be coming together as they reach the tip and exiting the same as the originals, so there's not too many ribs to deal with.
I would, however, just use a 3" BC. y1
Bill <><