F7A Bellcrank mod

14 posts in this topic

Posted

Finished up my bellcrank mod tonite. I can't rig it till I get my wings back on but I adjusted them really close to where they were before so it should not be too difficult. Here are a few pics since the ones that come with the instructions suck. Took longer to pull all the cotter pins out and put them in than it did to actually install the parts. Pretty simple.

The modified one is on the bottom. It uses the same links but the rods are much beefier than I had before. I just noticed I have the modified one laying opposite the stock one but you get the idea.

IMG_3785-1.jpg

IMG_3792.jpg

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Posted

Great Pictures, C5Engineer!!

The assembly view finally lets me follow the links and understand how the mixer works!

In that view, it looks like the flap actuating "bell-crank" has the paint rubbed off its triangulating brace.  Is that from a side load (bushing slop) or does it just fit in there that snug?

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Posted

It fits snug in that V notch. Mine was rubbing a little bit where the paint is missing. I shimmed it over with a washer and it's all good now.

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Posted

C5,

I should be getting my new F7s this week. How do you set the rigging for them?

Thanks,

Bandit

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Posted

Dave Fisher has an instruction on his website.  It's for a Kitfox, but, well, you know...  :nutkick:

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Posted

Interesting. I'll be needing bell crank, mixer, and linkages for a tandem seat fuselage with Avid wings.

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Posted

I would wonder if you will have room for an Avid style mixer with the second seat in the back.  JImChuk

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Posted

will be a tight fit as the mixer isn't that far behind the seats

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Posted

What's the deal with the revised F7's that rudder input doesn't compensate for? Not a sarcastic question. I've got about 2000 hours in various Avids. I probably couldn't even fly another plane. Fits like a suit to me. So what would I experience different and would it be awesome? I mean that sincerely. I've never flown one with revised F7s.

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Posted

It's been a long time since I flew one with the old style bellcranks, but I didn't think there was all that much difference.  I have a tendency to glance at the ball in turns, and just do what is says.  For that matter, my Kitfox 4 doesn't seem all that much different from my Avid as far as adverse yaw.  Actually the Avid tends to fly better it seems.  The Kitfox seems like it's balancing on a needle point.  The Avid seems to right itself, and flys hands off better.   Seems no matter what I do with the trim, the Kitfox either wants to climb or descend instead of flying level.  Same for bank.  It's stiffer on the controls as well then the Avid.  JImChuk

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Posted


I think the biggest benefit is when you pull the flap handle.  You can pull more flap before you get into the control reversal issue.

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Posted

I know this is an older thread and I am exposing my ignorance, but can someone explain what “ control reversal” is? Is this something specific to the Avid/Kitfox flaperon design?

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Posted

I know this is an older thread and I am exposing my ignorance, but can someone explain what “ control reversal” is? Is this something specific to the Avid/Kitfox flaperon design? 

Control reversal is when the wing as a whole is pretty close to stall and you put a large aileron input in, which increases the angle of attack of the wing you want to lift up. If you're right on the edge of stall, then instead of lifting that wing, it could stall and drop that wing. The pilot would perceive this as control reversal because you ask for a right roll and the aircraft rolls to the left. The cure for this is to use some washout so the tips of the wings are always slightly lower in angle of attack than the wing root. This means that the ailerons still have some lift left to control the roll axis even during the stall.

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Posted

Awesome! Thanks for the detailed response!

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