Wittman Buttercup / STOL

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planecrazzzy

Well-Known Member
Joined
Aug 16, 2003
Messages
330
Hey Guys,
I just thought I'd post the address of our
Buttercup Building Forum...

It's a cool plane , So far , in the Photo section I have around

900 building Pictures... So if your interested ... Here's the address:
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Buttercup-STOL : Buttercup STOL
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Steve Wittman designed this plane before the Famous "Tailwind"

It has a moveable "Leading Edge"... it works with the Flaps.

There's a lot of "Spec's" on the Home Page...
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Gotta Fly...
Mike & "Jaz" the Flying Dog
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planecrazzzy

Well-Known Member
Joined
Aug 16, 2003
Messages
330
You might have heard of Earl Luce...

He does some EAA "Building Tip" Clips...

He sells Prints.... Also , Aircraft Spruce is on board with

Material "Kits"... Although you need to look them over...

You can pick and choose... You don't have to buy everything

they have listed....

Gotta Fly...
Mike & "Jaz" the Flying Dog
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planecrazzzy

Well-Known Member
Joined
Aug 16, 2003
Messages
330

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berridos

Well-Known Member
Joined
Oct 10, 2009
Messages
1,134
Location
madrid
Hi guys

I just ordered the Buttercup plans and want to build it, but not out of tubing.
Do you know why the wing sides dont touch each other? I mean why there is a space above the cabin between the two wing sides?
Is this due to the tube construction or has it any aerodynamic reasons? Maybe because the wing is in front of the cabin start.

Regards
 

planecrazzzy

Well-Known Member
Joined
Aug 16, 2003
Messages
330
Hi berridos,
There is no space between the wings...
They attach to the Fuselage and trim pieces are made to
seal things off.... The Fuselage acts like a Lifting Body....
Which is very important in the Tailwind and it's shorter Wingspan.
But Helpful in the Buttercup for better STOL performance...
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If yer Building... You might wanna join our Buttercup/STOL site...
Buttercup-STOL : Buttercup STOL
When your there , you can find "links" to Building logs with
TONS of pictures....

Basiclly , showing how EASY this plane is to build....

Your "NOT" using tube ?????

That's the easiest, strongest, safest way to do it....
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You'd need to look at the Building logs ( WINGS FORUM )
Wings Forum :: View Forum - Wittman Aircraft
( Register once , Or Pictures "don't" show )
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Gotta Fly...
Mike & "Jaz" in MN
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PS Good Plans/Prints... But We can help in grey areas...
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bmcj

Well-Known Member
HBA Supporter
Joined
Apr 10, 2007
Messages
13,746
Location
Fresno, California
Hi guys

I just ordered the Buttercup plans and want to build it, but not out of tubing.
Do you know why the wing sides dont touch each other? I mean why there is a space above the cabin between the two wing sides?
Is this due to the tube construction or has it any aerodynamic reasons? Maybe because the wing is in front of the cabin start.

Regards
Several possible reasons come to mind:

1. The wings are elevated so the lower surface sits above the pilots field of view (for a less obstructed view). If the top surface continued all the way across, it would mean additional frontal area and (in my opinion) a wierd "hump".

2. The leading edges taper inward to help visibility from the cockpit. The airfoil shape here is maintained for lift and streamlining, which results is a tapering thickness too.

3. The reduced frontal area of the fuselage means less drag and less blocking of the propeller's airflow.

4. The strut braced wing only requires a single bolt on each inboard strut end, so the section can be thinner (tapered).

5. The fuselage cross-section can be smaller and lighter because it doesn't have to include the wing depth.

Bruce :)
 

planecrazzzy

Well-Known Member
Joined
Aug 16, 2003
Messages
330
Those are a lot of good points....
Gotta Fly...
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Several possible reasons come to mind:

1. The wings are elevated so the lower surface sits above the pilots field of view (for a less obstructed view). If the top surface continued all the way across, it would mean additional frontal area and (in my opinion) a wierd "hump".

2. The leading edges taper inward to help visibility from the cockpit. The airfoil shape here is maintained for lift and streamlining, which results is a tapering thickness too.

3. The reduced frontal area of the fuselage means less drag and less blocking of the propeller's airflow.

4. The strut braced wing only requires a single bolt on each inboard strut end, so the section can be thinner (tapered).

5. The fuselage cross-section can be smaller and lighter because it doesn't have to include the wing depth.

Bruce :)
 

berridos

Well-Known Member
Joined
Oct 10, 2009
Messages
1,134
Location
madrid
If the fuselage acts like a lifting body would it be inappropiate to round the fuselage and make it smoother and more aerodynamic?
If I round/smooth the fuselage i would improve it structurally when working with composites.
My goal also would be to avoid the use of struts.
I dont doubt that "tubing" is fast to build and light but i dont enjoy the work with it and for such a project that will take years i need to be comfortable with the material.
 

planecrazzzy

Well-Known Member
Joined
Aug 16, 2003
Messages
330
Yes,
You would not want to round it off.... Also...

On "my" fuselage... I took out the Whoopty do's...

Earl had added EXTRA in that Tadpole effect....

Steve only had one inch differance...( Earl made it three inches )

I made mine straight... So really.... Mines closer to Steve's design.
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Isn't composite heavier ??? People learn to work the tubing everyday... it really is "pretty easy"....
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Gotta Fly...
. Mike & "Jaz" in MN
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We have an expert on Tailwinds on the Buttercup site...
He's an A&P , and been around Tailwinds since he was a Kid...
You might wanna bounce some questions off of him...
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If the fuselage acts like a lifting body would it be inappropiate to round the fuselage and make it smoother and more aerodynamic?
If I round/smooth the fuselage i would improve it structurally when working with composites.
My goal also would be to avoid the use of struts.
I dont doubt that "tubing" is fast to build and light but i dont enjoy the work with it and for such a project that will take years i need to be comfortable with the material.
 

steveair2

Well-Known Member
Log Member
Joined
Jun 1, 2007
Messages
989
Location
Dallas Texas
Mike, your plane looks great! You have me considering a Buttercup for my next project. I like the way you squared off the stabilizers, I also like the straight lower longerons. The rudder and ailerons look to little.

Steve
 

planecrazzzy

Well-Known Member
Joined
Aug 16, 2003
Messages
330
Hi Steve,
I also have Tailwind prints...

My plane is more of a hybrid...

We Joke about "Buttwind" HA !!!!!!!!!!!
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. Gotta Fly...
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PS I have a detailed Building log at the Wings forum...

It helps to see what's involved... Basiclly... Showing how

EASY it is...
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Mike, your plane looks great! You have me considering a Buttercup for my next project. I like the way you squared off the stabilizers, I also like the straight lower longerons. The rudder and ailerons look to little.

Steve
 
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