Voisin Type 8 French Bomber - Flite Fest 2022 Dawn Patrol Build

[jaypbennett]

Well . . . here goes nothing. No plans, limited number of good pictures, and little to no experience scratch building. And at 1/6 scale I'm being told it could be the biggest airplane in the group.

What have I gotten myself into!!??

Good or bad I will be documenting the process in pictures here and video on my YouTube channel.

Here are some images of what I'm building and a couple pics from day one of 1/18 scale prototype. First video should be ready by the end of the week.





Wish me luck!

 

[wilmracer]

No plans, limited number of good pictures, and little to no experience scratch building. And at 1/6 scale I'm being told it could be the biggest airplane in the group.

Jumping in with both feet! There are some other big models in the works but yeah, 118" span is pretty big . Don't hesitate to reach out to the community here for help and suggestions. Many folks here have built with foam at that scale so there is a lot of knowledge to lean on.

Watching with interest!

 

[Baron VonHelton]

Well . . . here goes nothing. No plans, limited number of good pictures, and little to no experience scratch building. And at 1/6 scale I'm being told it could be the biggest airplane in the group.

What have I gotten myself into!!??

Good or bad I will be documenting the process in pictures here and video on my YouTube channel.

Here are some images of what I'm building and a couple pics from day one of 1/18 scale prototype. First video should be ready by the end of the week.

View attachment 216022 View attachment 216023 View attachment 216024

View attachment 216025 View attachment 216026 View attachment 216027

Wish me luck!

If I can do it with ZERO foam experience, anyone can.

 

[jaypbennett]

Decided to do two full wings for the 1/18 prototype. Bottom wing glued on and prop area cut out. Will be working on the rest of the wing supports this weekend. I'm thinking of just using hot glue and larger bbq skewers. Same for the tail supports. Almost looks like an airplane!

 

[wilmracer]

Nice start, and smart to start with a smaller scale prototype.

Are you planning FT style fold over wings? Io under cambered with a few exposed ribs to hold the shape? Just curious how you plan to approach wing strength at a LARGE scale.

Something I don't see much in the FT world is the use of Kline Fogleman airfoils (https://en.wikipedia.org/wiki/Kline–Fogleman_airfoil) aka KFM airfoils. They make for some quick and easy wing construction, some allow for incorporation of spars and hard points for cabanes and struts, and produce more lift than flat plate airfoils. There are even a few that can be built with added under camber. These may prove an easier way to tackle a BIG set of wings. Granted it is less scale but we're just having fun here and folder foam board wings aren't exactly period accurate either

If you don't already have a plan for when you scale up take a look at that wiki link. There is a diagram with a lot of variations of KFM that you may find useful. What I've seen others do is adjust the % of one or more of the surfaces and line the trailing edge with appropriately thick hardwood dowel or even CF tube. The laminations themselves add a ton of strength and the added structure can make them QUITE strong.

On edit: Good article from the FT articles section with some more detail on the advantages and uses of the various versions. https://www.flitetest.com/articles/kfm-wings-a-basic-explanation

 

[Yankee2003]

Decided to do two full wings for the 1/18 prototype. Bottom wing glued on and prop area cut out. Will be working on the rest of the wing supports this weekend. I'm thinking of just using hot glue and larger bbq skewers. Same for the tail supports. Almost looks like an airplane!
View attachment 216317 View attachment 216318

Nice progress. I like the bbq skewer idea.
Keep up the good work I like where it’s going.

 

[leaded50]

In 1974, a NASA-funded study prompted by Kline and Fogelman's claims and the resulting national coverage found the airfoil to have worse lift-to-drag ratio than a flat plate airfoil in wind tunnel tests.

A 2008 study by Fabrizio De Gregorio and Giuseppe Fraioli at CIRA and the University of Rome in Italy tried this out.[6] The model aerofoils used in their wind tunnel tests were equipped with numerous small holes through which air could be blown or sucked in an active way.
They concluded that the trapped vortex formed by a cavity or step could not be held in place without such active control. Just relying passively on wing shape wasn't enough – the vortex would detach possibly giving you worse characteristics than the original unstepped airfoil. But when active controls were used to keep the vortex stably in place they found the results "really encouraging".

 

[wilmracer]

In 1974, a NASA-funded study prompted by Kline and Fogelman's claims and the resulting national coverage found the airfoil to have worse lift-to-drag ratio than a flat plate airfoil in wind tunnel tests.

A 2008 study by Fabrizio De Gregorio and Giuseppe Fraioli at CIRA and the University of Rome in Italy tried this out.[6] The model aerofoils used in their wind tunnel tests were equipped with numerous small holes through which air could be blown or sucked in an active way.
They concluded that the trapped vortex formed by a cavity or step could not be held in place without such active control. Just relying passively on wing shape wasn't enough – the vortex would detach possibly giving you worse characteristics than the original unstepped airfoil. But when active controls were used to keep the vortex stably in place they found the results "really encouraging".

Interesting. I don't doubt what you're saying but would be curious to know if Nasa looked at scales and Renolds numbers in the ranges our models fly at. I've flown a load of parkjets with flat plate airfoils and they flew great, but I've always heard good things about the KFM wings too. It was just a thought though.

 

[cyclone3350]

Interesting. I don't doubt what you're saying but would be curious to know if Nasa looked at scales and Renolds numbers in the ranges our models fly at. I've flown a load of parkjets with flat plate airfoils and they flew great, but I've always heard good things about the KFM wings too. It was just a thought though.

I don’t know where I saw it, but there was a study on models. If I recall, the lift & strength to weight did better in KFM. Due to the Reynolds’s #, the drag wasn’t much of issue & was hard to detect a reduction in performance due to the insanely higher power to weight ratio in models. There may have been a reduction in range, but 10 min of flight time is unchanged. The difference may be 9 times in the pattern vs 10.

 

[Baron VonHelton]

I don’t know where I saw it, but there was a study on models. If I recall, the lift & strength to weight did better in KFM. Due to the Reynolds’s #, the drag wasn’t much of issue & was hard to detect a reduction in performance due to the insanely higher power to weight ratio in models. There may have been a reduction in range, but 10 min of flight time is unchanged. The difference may be 9 times in the pattern vs 10.

This what yer looking for?

 

[leaded50]

Interesting. I don't doubt what you're saying but would be curious to know if Nasa looked at scales and Renolds numbers in the ranges our models fly at. I've flown a load of parkjets with flat plate airfoils and they flew great, but I've always heard good things about the KFM wings too. It was just a thought though.

anyway, as you wrote....long foamborad wings would get a lot stronger with KF style, and that type of plane is not speeedy anyway

 

[wilmracer]

Any Updates?

 

[jaypbennett]

Unfortunately, the news is not good for the Voisin build but good for something else. Bad news . . . Voisin build is not happening, at least not by Flite Fest. Good news . . . I have a 5x8 enclosed cargo trailer that I'm converting to a tiny camper for all these RC festivals. So that is taking up all of my time prior to Flite Fest so I can camp in comfort.

I am posting camper build videos on my YouTube channel if anyone is interested.
https://www.youtube.com/jaypbennett