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I really don't know where else to post this question

buzzbomb

I know nothing!
#1
Since I'm a noob, and we're supposed to post noob questions here, I figured this would be the right place. I'm currently building a Mini Scout and the cool curves on the back of the wing just strike me as awesomely cool. Awesomely. Cool. Curves.

I did a quick Google Image search of biplanes, and those curves are not common. Do they serve a purpose other than aesthetic? Here's a pic of what I'm talking about:

IMG_0105.JPG
 

PsyBorg

Wake up! Time to fly!
#2
I think those scallops have something to do with how the old fabric wings may have stretched and sagged giving that effect.
 

buzzbomb

I know nothing!
#3
I think those scallops have something to do with how the old fabric wings may have stretched and sagged giving that effect.
Assuming the capability to build a spar across the back, I can't see it. How hard could it have been just to put some straight wood on the backside? Those scallops were made on purpose.
 

buzzbomb

I know nothing!
#4
In retrospect... I'm imagining the vertical spars, and then stretching fabric over them, and then trying to bring the fabric taught... Weight is bad. Let the fabric just curve... OK. I can see that. Given that scenario, it'd be really difficult to have the wing surface flat at the back. Wow.

When I close my eyes and just think about it. Wow.
 

cranialrectosis

Well-Known Member
Mentor
#6
In the olden days the word 'dope' meant something totally different than it does today.

Planes were made from wood with the trailing edge being a steel wire ran through the end of the ribs. The frame was then covered in cloth and painted with dope. The dope stuck the cloth to the ribs and spars and tightened the cloth like a hot iron does to monokote leaving little scallops on the back edges of wings where the wire was bowed due to tension as the dope shrinks the cloth.

Covering with dope.

Trailing edge with steel wire.

Of all the planes of that era, perhaps the most famous is the Fokker DR1. These photos clearly show the scallops left as the dope tightens the fabric on the frame. The dope NEVER stops tightening the cloth. If not properly maintained, it can eventually pull the airframe apart. Modern dope is plasticized to slow this effect but still tightens and shrinks the canvas covering over the years.

Here you can see a Blue Max from the rear.

Eventually they stopped using the wire and the scallops went away. Having a wood trailing edge would seem to me to make for a more rigid and effective flight control surface but that's just me speculatin'.

I think the scallops on the back of the Mini Scout are an homage to the pioneers who flew these insanely flammable airplanes in the pursuit of testing the limits of human ingenuity and courage.
 
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buzzbomb

I know nothing!
#7
In the olden days the word 'dope' meant something totally different than it does today.

Planes were made from wood with the trailing edge being a steel wire ran through the end of the ribs. The frame was then covered in cloth and painted with dope. The dope stuck the cloth to the ribs and spars and tightened the cloth like a hot iron does to monokote leaving little scallops on the back edges of wings where the wire was bowed due to tension as the dope shrinks the cloth.

Covering with dope.

Trailing edge with steel wire.

Of all the planes of that era, perhaps the most famous is the Fokker DR1. These photos clearly show the scallops left as the dope tightens the fabric on the frame. The dope NEVER stops tightening the cloth. If not properly maintained, it can eventually pull the airframe apart. Modern dope is plasticized to slow this effect but still tightens and shrinks the canvas covering over the years.

Here you can see a Blue Max from the rear.

Eventually they stopped using the wire and the scallops went away. Having a wood trailing edge would seem to me to make for a more rigid and effective flight control surface but that's just me speculatin'.

I think the scallops on the back of the Mini Scout are an homage to the pioneers who flew these insanely flammable airplanes in the pursuit of testing the limits of human ingenuity and courage.
Awesome. One less mystery in life. Thank you. They had some serious skills to build a wood frame that could withstand that kind of tensioning and be light enough to fly. Hugely impressive.
 
#8
Goes back to the Ww1 plane designs....(aka back wing of the Fokker dr1). Yes truly scary what some of them were made out of.... and what you could & could not step on getting in & out.
 

buzzbomb

I know nothing!
#9
"Flyboys" is one of my favorite movies. It doesn't show the build process, but as far as I know it depicts what it was like to fly those things in combat. Wood, fabric, wire and a motor. Then they just took off and battled it out. Truly awe-inspiring.
 
#10
The flyboys replicas, if memory serves we’re built from scale reproduction kits by http://www.airdromeaeroplanes.com Now these are (if memory serves) aluminium frames... which is still no small accomplishment. If you want to see a group that flies these things (ww1 replicas about 75-80% scale) regularly look up the Kansas City Dawn Patrol... http://www.dawnpatrol.org/index.php Both are fun sites to look at.

I once had a chance to see a caproni bomber at the us Air Force museum... it is frightening imagining being in that front gun tub & not imagine falling out or going through the rather flimsy floor boards. 😀
 

buzzbomb

I know nothing!
#11
Something I picked up through the years: In the beginning, they shot up the prop (That's why the guns were high). Not good. So they put lead shields on the prop where the bullets would hit. Less than optimal. Then somebody came up with a brake that only fired the gun when the prop was not there! That's genius level stuff.

I'm cutting cardstock and foam board in the hope that my little RC plane will fly. I cut the scallops with all the perfection I could muster. An homage to to those brave men? Nah. Not even close. I'm glad those scallops are part of this plane, though.