Wright Stuff C

Airco2020
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Re: Wright Stuff C

Post by Airco2020 » November 18th, 2019, 12:30 pm

lechassin wrote:
November 17th, 2019, 11:48 am
I don't have any videos to post from today but it was all Luke flying the plane he built. In order to keep things simple and sturdy/reliable, he used a rigid (non-flaring) prop and has permanently centered wings, with a 1mm shim that he adds under the leading edge for left circles. We did tinker with the motor length and he's consistently 1'35" to 1'45" in both directions with few knots remaining. He's winding to 4440 initially, then back to 4170, launching at 0.3 in.oz torque. That's where we left things in anticipation of his first invitational next Saturday. Of course we have no way of knowing where he will stand because NOBODY IS POSTING TIMES (sorry for yelling ;) ). He did start to build a back-up plane; he should have it done for the invitational but obviously not fully trimmed (lesson in time management...)

I didn't fly mine at all with my new motors because I spent the morning helping my younger boy with elastic-launch gliders. We're getting 12-16 seconds at 25' altitude which is pretty good, considering that last week we just made balsa debris...
Still waiting on delivery of my kit!!!! Teacher claimed he ordered....going to be rough at the first invitational. I think I'll go your route and build from scratch.

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Re: Wright Stuff C

Post by lechassin » November 18th, 2019, 2:24 pm

I think scratch is the way to go. Not only does it better suit the intent of WS as I interpret it ("design, build and fly", IIRC), but it's waaaay more cost effective, doesn't take any longer than a kit, and you're not fixed/tied to someone else's ideas. If you don't have ideas, no matter: the rules dictate most of the layout so there's actually not much to think about. We've never won anything, but here's our design for whatever it's worth, as seen in the videos (sorry it's long):

In general:

The ribs, wing fences, and tail feathers are made of strips we cut from middle weight 1/32" balsa sheets (EBay). The only sticks we buy ready to use: the motor stick is firm 3/32"x1/4", the wing leading and trailing edges are firm 1/16"x1/8", and the tail boom is light 1/16"x3/16". There are no "butt" joints; all glue joints overlap so the surfaces aren't as flat as they could be but the plane is STRONG. Lay out the design with tape on a flat surface and build directly on that, taping the initial pieces down so everything stays square and flat. The structure is glued with tiny dabs of Gorilla Superglue (Home Depot) applied with tooth picks, with some areas soaked in thin CA and hardener (EBay). Covering is thin bags wrinkled tightly (repeatedly) and then spread onto a frame, held to the frame with Vaseline, lowered onto the wings/tail feathers/fences after the bits are sprayed with 3M 77(Home Depot). Some folks use dry cleaning bags, we've used grocery/veggie bags or even better, these super thin bags from our health club (for wet bathing suits).

1) Build two 29.4cm x8cm wings: 1/16"x1/8" leading and trailing edges, ribs are cut from long 3/32"x 1/32" strips taped wet around a dinner plate "template" to create the airfoil.
2) Build the 12x6 stab as a rectangle of 3/32"x1/32" strips, same with rudder, it's about 1.75"x1.25".
3) Build two wing brace/fences from 1/16"x1/32" strips: a 7.3 cm vertical, a 10.3 cm vertical, two horizontals, two triangulating segments. The glue joints overlap, so be sure to build a right and a left side.
4) Cover all those pieces .
5) Glue the fences to the wings using blocks to be sure that everything is perfectly square and the wings are flat (no twists). Just tack things at first, the final result is rigid so if it's crooked, it will stay that way. If needed, pop glue joints loose and adjust. When you're satisfied, soak the joints with thin Superglue.
6) Weight the stab flat and glue the tail boom. Leave the tail boom 12" (a bit too long) for now, you'll see why later.
7) Rudder hinge: glue half of a 1/4"x1/4" piece of thick paper to a corner of the rudder's leading edge, and glue the other half to a scrap of 1/8"x1/16" balsa that sticks out enough that it can be tack-glued to the side of the tail boom. Soak the area with thin Superglue, the paper becomes the hinge.
8) Cut a 1/2"x 1/32" strip from a soda can and glue it into a slot in the rear of the tail boom so it sticks out under the rudder's trailing edge on both sides. Curl it so it acts as an easily adjustable rudder trim tab (our rudder moves about 1/8" either way).

Here is the rudder (and offsetting wing mounts): https://www.youtube.com/watch?v=TSLT4MTYc74

9) Cut the motor stick to 18" and mount your hub and rear hook according to your preferences, zero degrees thrust angles, and exactly 1/4" clearance from the middle of the hooks to the stick.
10) Weigh all of that with the prop you intend to use. Expect the plane to be 8+ grams at this point. Taper the motor stick no thinner than 1/8" at the ends to get it all as far below 8 grams as possible. This will leave wiggle room for final glue joints, wing shims/mounts, and a little ballast you can remove as repair glue accumulates.
11) Glue the wing trailing edge to the motor stick 12.5" from the nose. This will yield the simpler design Luke uses where the incidence of the wings can be adjusted, but not the right/left offset. The offset keeps the wings level while turning, with none of the drag or complexity of wing warping adjustments. Omitting the offset produces a 5 second performance penalty, but it is much simpler, and things can easily be modified later to have the adjustable offset.
12) Glue two small verticals to the wing's leading edge that slide over the sides of the motor stick. Make a shim that slides in and out between the verticals under the leading edge, 3-5mm range. A rubber band for orthodontia holds the leading edge onto the shim. The wing incidence going to the right needs to be 1mm less and the shim makes the adjustment, and also accounts for all the 3.5-4.5mm decalage in the design (and also means there's a few degrees down thrust built in to control initial climb angle).
13) Mark the target CG which is 23mm from the leading edge with no motor. (I forget where the CG is with our 33" motor, but you can mark that when the plane is done so you know where to put ballast as you try different motors).
14) Tack glue the tail boom repeatedly, shortening it as little as possible to balance the plane right on your CG mark. Our booms end up about 28cm long, the distance from the wing's trailing edge to the stab's leading edge is about 37cm. The longer the better, resistance to turbulence may be marginal otherwise.

Our 3 bladed props are 1.1 grams without the drive shaft and bearing/mount. If you're using a two bladed (lighter) prop you may be able to extend the motor stick forward to keep the CG, and have the opportunity for an even longer motor with more knots in it than we have. That may actually be necessary in order to compete with a 3 bladed prop (you'll need to spin 2 blades faster to get equal thrust, ergo more knots to stay aloft as long). When we went to 3 blades the difference was something like 15 seconds with no other changes, so we haven't looked back. I don't know what others are experiencing because NOBODY IS POSTING FLIGHT TIMES (sorry for yelling ;)

I know that's long, hope it helps somebody.
Last edited by lechassin on November 18th, 2019, 3:36 pm, edited 1 time in total.

ilovebiologyPA
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Re: Wright Stuff C

Post by ilovebiologyPA » November 18th, 2019, 2:28 pm

lechassin wrote:
November 18th, 2019, 2:24 pm
I think scratch is the way to go. Not only does it better suit the intent of WS as I interpret it ("design, build and fly", IIRC), but it's waaaay more cost effective, doesn't take any longer than a kit, and you're not fixed/tied to someone else's ideas. If you don't have ideas, no matter: the rules dictate most of the layout so there's actually not much to think about. We've never won anything, but here's our design for whatever it's worth, as seen in the videos (sorry it's long):

In general:

The ribs, wing fences, and tail feathers are made of strips we cut from middle weight 1/32" balsa sheets (EBay). The only sticks we buy ready to use: the motor stick is firm 3/32"x1/4", the wing leading and trailing edges are firm 1/16"x1/8", and the tail boom is light 1/16"x3/16". There are no "butt" joints; all glue joints overlap so the surfaces aren't as flat as they could be but the plane is STRONG. Lay out the design with tape on a flat surface and build directly on that, taping the initial pieces down so everything stays square and flat. The structure is glued with tiny dabs of Gorilla Superglue (Home Depot) applied with tooth picks, with some areas soaked in thin CA and hardener (EBay). Covering is thin bags wrinkled tightly (repeatedly) and then spread onto a frame, held to the frame with Vaseline, lowered onto the wings/tail feathers/fences after the bits are sprayed with 3M 77(Home Depot). Some folks use dry cleaning bags, we've used grocery/veggie bags or even better, these super thin bags from our health club (for wet bathing suits).

1) Build two 29.4cm x8cm wings: 1/16"x1/8" leading and trailing edges, ribs are cut from long 3/32"x 1/32" strips taped wet around a dinner plate "template" to create the airfoil.
2) Build the 12x6 stab as a rectangle of 3/32"x1/32" strips, same with rudder, it's about 1.75"x1.25".
3) Build two wing brace/fences from 1/16"x1/32" strips: two verticals, two horizontals, two triangulating segments. The glue joints overlap, so be sure to build a right and a left side.
4) Cover all those pieces .
5) Glue the fences to the wings using blocks to be sure that everything is perfectly square and the wings are flat (no twists). Just tack things at first, the final result is rigid so if it's crooked, it will stay that way. If needed, pop glue joints loose and adjust. When you're satisfied, soak the joints with thin Superglue.
6) Weight the stab flat and glue the tail boom. Leave the tail boom 12" (a bit too long) for now, you'll see why later.
7) Rudder hinge: glue half of a 1/4"x1/4" piece of thick paper to a corner of the rudder's leading edge, and glue the other half to a scrap of 1/8"x1/16" balsa that sticks out enough that it can be tack-glued to the side of the tail boom. Soak the area with thin Superglue, the paper becomes the hinge.
8) Cut a 1/2"x 1/32" strip from a soda can and glue it into a slot in the rear of the tail boom so it sticks out under the rudder's trailing edge on both sides. Curl it so it acts as an easily adjustable rudder trim tab (our rudder moves about 1/8" either way).

Here is the rudder (and offsetting wing mounts): https://www.youtube.com/watch?v=TSLT4MTYc74

9) Cut the motor stick to 18" and mount your hub and rear hook according to your preferences, zero degrees thrust angles, and exactly 1/4" clearance from the middle of the hooks to the stick.
10) Weigh all of that with the prop you intend to use. Expect the plane to be 8+ grams at this point. Taper the motor stick no thinner than 1/8" at the ends to get it all as far below 8 grams as possible. This will leave wiggle room for final glue joints, wing shims/mounts, and a little ballast you can remove as repair glue accumulates.
11) Glue the wing trailing edge to the motor stick 12.5" from the nose. This will yield the simpler design Luke uses where the incidence of the wings can be adjusted, but not the right/left offset. The offset keeps the wings level while turning, with none of the drag or complexity of wing warping adjustments. Omitting the offset produces a 5 second performance penalty, but it is much simpler, and things can easily be modified later to have the adjustable offset.
12) Glue two small verticals to the wing's leading edge that slide over the sides of the motor stick. Make a shim that slides in and out between the verticals under the leading edge, 3-5mm range. A rubber band for orthodontia holds the leading edge onto the shim. The wing incidence going to the right needs to be 1mm less and the shim makes the adjustment, and also accounts for all the 3.5-4.5mm decalage in the design (and also means there's a few degrees down thrust built in to control initial climb angle).
13) Mark the target CG which is 23mm from the leading edge with no motor. (I forget where the CG is with our 33" motor, but you can mark that when the plane is done so you know where to put ballast as you try different motors).
14) Tack glue the tail boom repeatedly, shortening it as little as possible to balance the plane right on your CG mark. Our booms end up about 28cm long, the distance from the wing's trailing edge to the stab's leading edge is about 37cm. The longer the better, resistance to turbulence may be marginal otherwise.

Our 3 bladed props are 1.1 grams without the drive shaft and bearing/mount. If you're using a two bladed (lighter) prop you may be able to extend the motor stick forward to keep the CG, and have the opportunity for an even longer motor with more knots in it than we have. That may actually be necessary in order to compete with a 3 bladed prop (you'll need to spin 2 blades faster to get equal thrust, ergo more knots to stay aloft as long). When we went to 3 blades the difference was something like 15 seconds with no other changes, so we haven't looked back. I don't know what others are experiencing because NOBODY IS POSTING FLIGHT TIMES (sorry for yelling ;)

I know that's long, hope it helps somebody.
can you be my dad so you can boost me pls

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Re: Wright Stuff C

Post by Airco2020 » November 18th, 2019, 2:39 pm

WOW! Thanks for all the information. It's great that you are so willing to share your expertise!

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klastyioer
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Re: Wright Stuff C

Post by klastyioer » November 20th, 2019, 4:33 pm

lechassin wrote:
November 17th, 2019, 11:48 am
I don't have any videos to post from today but it was all Luke flying the plane he built. In order to keep things simple and sturdy/reliable, he used a rigid (non-flaring) prop and has permanently centered wings, with a 1mm shim that he adds under the leading edge for left circles. We did tinker with the motor length and he's consistently 1'35" to 1'45" in both directions with few knots remaining. He's winding to 4440 initially, then back to 4170, launching at 0.3 in.oz torque. That's where we left things in anticipation of his first invitational next Saturday. Of course we have no way of knowing where he will stand because NOBODY IS POSTING TIMES (sorry for yelling ;) ). He did start to build a back-up plane; he should have it done for the invitational but obviously not fully trimmed (lesson in time management...)

I didn't fly mine at all with my new motors because I spent the morning helping my younger boy with elastic-launch gliders. We're getting 12-16 seconds at 25' altitude which is pretty good, considering that last week we just made balsa debris...
i mean theres a reason why people don't post times
thats why you have to go to invitationals and watch other ppls flights
it's not about the medals; go out there and have fun. make progress, learn a few things, have one heck of a time, because that's all that matters.

Builder Cult >:)

'17 - Towers, WS, rocks
'18 - Towers, WS, Mystery Arch, road
'19 - WS
'20 - WS, Boomilever, PPP

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Re: Wright Stuff C

Post by lechassin » November 21st, 2019, 6:29 am

klastyioer wrote:
November 20th, 2019, 4:33 pm
theres a reason why people don't post times
Not any good reason, IMO. Sharing every shred of data will not hurt the best teams one bit. They will continue to have a pipeline of information that is unbeatable. Share the wealth, everyone will improve, and nothing will change at the top.

Or don't share. We'll figure it out, and then we'll keep it to ourselves. All of it ;) .

jander14indoor
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Re: Wright Stuff C

Post by jander14indoor » November 21st, 2019, 7:05 am

lechassin wrote:
klastyioer wrote:
November 20th, 2019, 4:33 pm
theres a reason why people don't post times
Not any good reason, IMO. Sharing every shred of data will not hurt the best teams one bit. They will continue to have a pipeline of information that is unbeatable. Share the wealth, everyone will improve, and nothing will change at the top.

Or don't share. We'll figure it out, and then we'll keep it to ourselves. All of it ;) .
I'm with you. We can tell you everything about how to build and fly a Wright Stuff plane, but if you don't do the work, you STILL won't succeed. If you do the work, you will.

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xiangyu
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Re: Wright Stuff C

Post by xiangyu » November 21st, 2019, 7:51 am

lechassin wrote:
November 21st, 2019, 6:29 am
klastyioer wrote:
November 20th, 2019, 4:33 pm
theres a reason why people don't post times
Not any good reason, IMO. Sharing every shred of data will not hurt the best teams one bit. They will continue to have a pipeline of information that is unbeatable. Share the wealth, everyone will improve, and nothing will change at the top.

Or don't share. We'll figure it out, and then we'll keep it to ourselves. All of it ;) .
I agree. See, that's the things about Science Olympiad that I don't like. There is not much collaboration between teams. In the world today, I think it is quite important to understand the values in collaboration. Of course, that doesn't mean that everyone should share their deepest secrets, but I think basic things like times wouldn't suddenly allow the other teams to be super good. The times are merely an indicator of potential and encourage me to continue to tweak things and improve.

Thank you, Lechassin, and all others on the forum for sharing your wealth of knowledge, I will continue to contribute as I gain progress!
So, please, keep posting and continue the discussion. Everyone is better off this way.
Xiangyu
2020 Events: Wright Stuff, Gravity Vehicle. Circuit Lab, Boomilever, Ping-Pong Parachute, WIDI

Inv.1/Inv.2/Reg
WS: 4/1st :D /
WIDI: 13/2nd :o /
Boom: 1st/1st :D /
Circuit: 15/7 :) /
GV: - /5 :? /
PPP: - /6 :cry: /

Medal & Ribbon Count: 8
East Grand Rapids High School Team Captain

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klastyioer
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Re: Wright Stuff C

Post by klastyioer » November 21st, 2019, 9:20 am

lechassin wrote:
November 21st, 2019, 6:29 am
klastyioer wrote:
November 20th, 2019, 4:33 pm
theres a reason why people don't post times
Not any good reason, IMO. Sharing every shred of data will not hurt the best teams one bit. They will continue to have a pipeline of information that is unbeatable. Share the wealth, everyone will improve, and nothing will change at the top.

Or don't share. We'll figure it out, and then we'll keep it to ourselves. All of it ;) .
that sounds like a bit of a threat...
i would if i could but i can't its team policy
i do think its kinda dumb it doesnt provide any harm to the teams who do share
it only benefits the majority but not in a way thatll improve their performance, only their priorities
it's not about the medals; go out there and have fun. make progress, learn a few things, have one heck of a time, because that's all that matters.

Builder Cult >:)

'17 - Towers, WS, rocks
'18 - Towers, WS, Mystery Arch, road
'19 - WS
'20 - WS, Boomilever, PPP

ilovebiologyPA
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Re: Wright Stuff C

Post by ilovebiologyPA » November 21st, 2019, 9:33 am

lechassin wrote:
November 21st, 2019, 6:29 am
klastyioer wrote:
November 20th, 2019, 4:33 pm
theres a reason why people don't post times
Not any good reason, IMO. Sharing every shred of data will not hurt the best teams one bit. They will continue to have a pipeline of information that is unbeatable. Share the wealth, everyone will improve, and nothing will change at the top.

Or don't share. We'll figure it out, and then we'll keep it to ourselves. All of it ;) .
why do u have a bad word in ur username, lechassin?

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