Backcountry Pilot • Whee's Bearhawk Project...Airworthiness Certificate issued!

Whee's Bearhawk Project...Airworthiness Certificate issued!

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Re: Whee's Bearhawk Project...the adventure begins

Just got off the phone with Bob. I called to talk about the trim system so I could come up with a plan. He agreed that since I will be flying with an aft CG frequently then I should eliminate as much servoing action of the trim tabs as possible. We talked about Pat Fagan's trim system and he thought it would work well for me but would cause higher than desirable stick pressures when lightly loaded. The plan we came up with is to extend the arm that comes off the trim tab that the pushrod connects to. The longer the arm the less servo action there will be. Cool, got a plan and moving on.
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Re: Whee's Bearhawk Project...the adventure begins

whee wrote:Just got off the phone with Bob. I called to talk about the trim system so I could come up with a plan. He agreed that since I will be flying with an aft CG frequently then I should eliminate as much servoing action of the trim tabs as possible. We talked about Pat Fagan's trim system and he thought it would work well for me but would cause higher than desirable stick pressures when lightly loaded. The plan we came up with is to extend the arm that comes off the trim tab that the pushrod connects to. The longer the arm the less servo action there will be. Cool, got a plan and moving on.


Nice. So the arm on the tab itself? I might do the same. I have my trim system ready to drill and bolt. Had to fabricate new pushrods, but got the bend(s) perfect. All that's left is to drill the holes through the torque tube and bolt em. I might hold off on that though given this new information.

Did Bob mention anyone else who had done that?
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Re: Whee's Bearhawk Project...the adventure begins

Zzz wrote:So the arm on the tab itself? Did Bob mention anyone else who had done that?


Yes, the arm on the tab itself. He did say you could raise the hole on the stabilizer side if you wanted/needed even more reduction in servo action but that would mean putting a depression in the skin of the stab.

He did not say if anyone had done this. It would be a really easy change so I'll likely just make it per the drawings and add an extension as I fly it to get it were I want.
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Re: Whee's Bearhawk Project...the adventure begins

I don't have a bearhawk, nor have I ever built an airplane, but what's wrong with having a completely non-servo'd trim tab? My two 150's & my 170 had non-servo'd trim and they all worked just fine.
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Re: Whee's Bearhawk Project...the adventure begins

Servo tabs lighten control forces. If there's a heavy elevator and light ailerons a servo tab can help balance control harmony.
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Re: Whee's Bearhawk Project...the adventure begins

CamTom is right on. IMO the Bearhawk is too light on the elevator so I want to make it a little heavier.
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Re: Whee's Bearhawk Project...the adventure begins

Brian-StevesAircraft wrote:Whee,

I can't remember who makes it but there is a mod for Super a Cubs that adds a front brace to the elevator. The brace moves with the jack screw. Friend of mine has it on his amphibian Cub... You could probably fab up a system that is similar and have the trimable stab..

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Re: Whee's Bearhawk Project...the adventure begins

whee wrote:Mark, can you send me those pics of Pats setup? I thought you were talking about Morse/Telex push/pull cables.
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Re: Whee's Bearhawk Project...the adventure begins

Whee...where you looking for pics of the Bearhawk float fittings?
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Re: Whee's Bearhawk Project...the adventure begins

Thanks for the pics Mark. I think I'm good with the float fittings. Paul M has a pic of them on the kitlog site. I just made a extra set of gear leg fittings. Where I'd have to machine a block for the floats I don't see why I can't use a gear leg fitting mounted at the float location. But then, I don't know anything about floats.
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Re: Whee's Bearhawk Project...progress.

Gear legs going on.

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Re: Whee's Bearhawk Project...progress.

Awesome!
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Re: Whee's Bearhawk Project...progress.

Another pic because I'm kinda excited. I know as soon as the fittings are welded it will come back off the gear but seeing the legs attached seems like a major milestone. I was having a hard time finding the springs for the shock struts as spec'd in the drawings. I got the part number from Avipro and ordered them so I should get those on next week. I couldn't find them because I was looking for a 3000# spring and the ones supplied with the kits seem to be 2300# springs (PN: EH200-800 from Dayton Progress). I don't know anything about springs so I'm content going with what Bob says.

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Re: Whee's Bearhawk Project...progress.

Are you going to build a rotisserie?
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Re: Whee's Bearhawk Project...progress.

whee wrote: Another pic because I'm kinda excited. I know as soon as the fittings are welded it will come back off the gear but seeing the legs attached seems like a major milestone..........


If you've got the MLG wheels on hand, you should mount them & take some more photos. It's amazing how much more these projects look like an airplane when they're sitting on the wheels. Ditto the wings- even uncovered and tip-less.
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Re: Whee's Bearhawk Project...progress.

m_moyle wrote:Are you going to build a rotisserie?

Not planning to but know when it comes time to cover it will probly be really nice so...maybe.

hotrod180 wrote:If you've got the MLG wheels on hand, you should mount them & take some more photos. It's amazing how much more these projects look like an airplane when they're sitting on the wheels. Ditto the wings- even uncovered and tip-less.


Don't have wheels yet. I can't decide which route I want to go and I don't need them yet so I'm not too worried about it.
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Re: Whee's Bearhawk Project...progress.

whee wrote:
m_moyle wrote:Are you going to build a rotisserie?

Not planning to but know when it comes time to cover it will probly be really nice so...maybe.

hotrod180 wrote: Don't have wheels yet. I can't decide which route I want to go and I don't need them yet so I'm not too worried about it.


I'd go with the round ones. =P~
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Re: Whee's Bearhawk Project...progress.

hotrod180 wrote:I'd go with the round ones. =P~

Think I know where a couple of these are...they are round.
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Re: Whee's Bearhawk Project...progress.

whee wrote:
hotrod180 wrote:I'd go with the round ones. =P~

Think I know where a couple of these are...they are round.
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That'd make for a funny picture for sure
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Re: Whee's Bearhawk Project...progress.

Cantom12, Whee and CamTom12 wrote:

whee wrote:

hotrod180 wrote:I'd go with the round ones. =P~
Think I know where a couple of these are...they are round.

I think ROUND wheels on aircraft are just so yesterday. Why not up your game and go with another shape ? I mean SQUARE sounds pretty cool.

Image
Image

Here is a video showing how well square wheels work.
https://www.youtube.com/watch?v=LgbWu8zJubo

I mean you can have a square engine with stroke and bore being equal. You can run an engine square say 26 and 26. You can run square-tailed Cessnas. Hey, it seems only natural to run square wheels... makes sense to me.
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