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FF2017 Int. Racers: Caudron C.460

rockyboy

Skill Collector
Mentor
#1
I am SO EXCITED about the upcoming 2017 Flite Fest International Air Races and FTFF 2017 International Air Races Design Off!! :applause:

I love this era of plane - the most graceful flying machines ever built (IMHO)

So for the build challenge, and my very first scratch build design, I'll be tackling the Caudron C.450/C.460

1352980735_13_FT33377_caudron_c460_02.jpg

1280px-Salon_du_Bourget_20090619_136.jpg

From looking at historical technical papers, the only difference between the planes is the addition of retractable landing gear on the C.460 - all other shapes of the plane, power plant, etc. stayed the same between the models. I'll be doing the prototype as a belly lander, so we'll call it a C.460

I've been rolling through the excellent tutorial videos and info from NerdNic and LocalFiend to learn more about this DTFB design stuff. Initially I've been using InkPad - an SVG editor for the iPad with layer and image importing support - cause it's more portable than my desktop. However, I find that when I export an SVG out from InkPad it will load into Inkscape, but I can't go back in the opposite direction. So that's a little awkward. Eventually the plans will be moved into a CAD package for CNC / Laser cutting.

The plan is to use a standard FliteTest power pod and about a 40" wing span. I'd love to keep a rounded fuselage shape so there will be some poster board and former construction going on. I really liked the removable hatch design on AirPirate's Rascal Racer, and will see if I can work something similar in. Also supremely impressed with NerdNic's wing designs, and will be paying close attention to the Chipmunk's proportions as I get this closer to the prototype stage.

I found a good 3 view and started tracing.

a771165-137-caudron_c460_3view.jpg

Have the main shapes and wing worked out so far.

Caudron C.450 v1.jpg

More progress to post soon - the computer design part is much quicker than the physical building :)

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Plans, Skins, and Electronics Requirements
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Next time I'll put up a second post when I initially start the design thread as a place to park the final files. But for now, I'll just be updating this addendum to the first post.

Here's what she looks like before the maiden flight :) Keep reading to see what happened later... :black_eyed:

2017-02-08 17.19.07.jpg
2017-02-08 17.18.15.jpg

The zip file linked below has a svg and pdf version of the plans with notations for which parts are plywood vs foam and where the bamboo reinforcement skewers go. Also included are plans and skins files are both pdf with the paper size set for Arch E size (36" x 48") that Staples can use to make color engineering prints so you don't have to live through the paper tiling process.

Caudron C.460 Plans & Skins v12.1 ZIP

This is the 1/6 scale set which is a good bit bigger than my initial prototype. She tips the scales at 33 oz - just a touch over 2 pounds with a 3s2200 battery.

Going with a Power Up 25 Speed 1100kv from Heads Up Hobby which has a power and performance profile right between NerdNic's recommended "Advanced" and "Speed" setups for his 40" wingspan planes. Paired up with a 60amp ESC, 6 amp BEC, and starting with an 11x5.5 prop first for a 'little' more thrust to keep airborne, and after better understanding the flight characteristics switching to a 10x7 prop for more forward airspeed.

Build instructions are in this thread starting at Post #80
 
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HilldaFlyer

Well-known member
#2
This is going to be hot!
My prototype will also be belly lander, hand launched - of course.
How are you planning on doing the fuselage?
 

rockyboy

Skill Collector
Mentor
#3
Thanks!

In the spirit of 'borrowing' from the best, I'm looking to AirPirateNinsei's Rascal Racer for fuselage structure inspiration, and the wing internals of course from NerdNic's Chipmunk v2.

I figure designing is probably just like building - it's best to start close to something that already works, learn why, and then start getting further afield with the crazy ideas. :)
 
#4
Here's a build thread that I worked up. The plane is still on my garage wall in disrepair waiting for its second chance. I'm not convinced that it would fly well with scale sized control surfaces.

Maybe some info here will help you out.
http://forum.flitetest.com/showthread.php?14063-Scale-Build-Off-Caudron-C-450-Build

Looking back on the thread it crazy how "beginner" it all was. Maybe I need to revisit this plane as well. It's kinda been a thorn in my side since the failed maiden.

Good luck to ya.
 

rockyboy

Skill Collector
Mentor
#5
Here's a build thread that I worked up. The plane is still on my garage wall in disrepair waiting for its second chance. I'm not convinced that it would fly well with scale sized control surfaces.

Maybe some info here will help you out.
http://forum.flitetest.com/showthread.php?14063-Scale-Build-Off-Caudron-C-450-Build

Looking back on the thread it crazy how "beginner" it all was. Maybe I need to revisit this plane as well. It's kinda been a thorn in my side since the failed maiden.

Good luck to ya.
Very cool!! Thank you so much for the link - the 3 view you have is much better - it has the fuse former shapes! :)

And you have almost 2 years more experience now - you should absolutely revisit and get her flying! She looks great, and that rudder linkage hookup is a very cool idea.

Looking at all the discussion and experience, I will definitely increase the tail control surfaces. Probably extend the rudder line up so I leave the overall shape more intact. And rethink the lack of landing gear - a rolling take off might be just what this plane needs.

Thanks!
 
#6
A rolling takeoff is definitely a good idea. I was always thinking of using a cat launch and belly landing. Landing gear seemed like a weight increase that would only increase the already high wing loading. This would make flaps necessary which would increase the over all weight and loading even further. The other problem I saw with landing gear was a pretty high approach speed which means lots of roll out. I don't have a place to fly here that is suitable for such a long roll out with such small gear.

Either way you go unless you can build way lighter than I did I think hand launching is out. I could be wrong though. I've been contemplating throughing a more powerful motor setup in the airframe, taping it back together and seeing if she goes.

Or build this, scratch the c450 itch and move on.
http://www.jivaro-models.org/caudron_460_mathieu/page_caudron460.htm
 

rockyboy

Skill Collector
Mentor
#8
Plans progressing along...

While I started the outline on InkPad (iPad app) I moved over to Inkscape for the next phase of work - figuring out the foam shapes. I figure the prototype will be a little rougher - not worrying so much about the rounded top for instance. Mostly need to see if the proportions will fly. For example, I extended the control surfaces to the edge of the structure (instead of just a smaller control flap). Want to see if it will fly, or if I need to adjust, before I make the pretty one.

caudron c.460.png
 
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rockyboy

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Mentor
#9
Tonight's progress: increased the rudder and elevator to 125% from scale, and prepared the basic skin design. I added a red/white/blue stripe on the wing tip near the race number to help with orientation in the air. I think it fits rather well with the similar (but thinner) stripes across the fuse.

caudron c.460.png

To do:
- Create wing saddle shape in fuse
- Create folded elevator and rudder foam shapes (I was going to do that tonight, but got distracted with the pretty stuff).
- Create HHL (Hatch Hook and Latch) fuse top (AirPirateNinse style!)
- Prepare foam shapes in CAD for CNC/laser cutting
- Build the prototype
- Crash
- Adjust plans (build out all the nice formers for the more rounded fuse)
- Prepare skin with flattened foam shapes
- Build prototype v2 (the pretty one)
- Fly!

Simple! :)
 
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rockyboy

Skill Collector
Mentor
#11
Glad to have your eyes on it! :)

And, you're doing more than watching (virtually speaking). I'm progressing with the design while streaming your tutorial videos, and there are hidden layers in the file for the NerdNic speed wing and empanage I'm using to check my airfoil proportions - so thank you!! :)
 

rockyboy

Skill Collector
Mentor
#12
Either way you go unless you can build way lighter than I did I think hand launching is out. I could be wrong though. I've been contemplating throughing a more powerful motor setup in the airframe, taping it back together and seeing if she goes.
I don't think I saw your all up weight in the build thread - any idea how much she tipped the scales at?
 

rockyboy

Skill Collector
Mentor
#13
Tonight's progress:
- Installed development trunk of Inkscape - really like the new tool snap features - works very similar to AutoCAD now! I can actually move and draw with accuracy finally!
- Cleaned up a bunch of corners that were aligned OK enough for printing, but not so much for CNC
- Create folded elevator and rudder foam shapes, and better round out all their pointy edges

caudron c.461.png

To do:
- Create wing saddle shape in fuse
- Create HHL (Hatch Hook and Latch) fuse top (AirPirateNinse style!)
- Prepare foam shapes in CAD for CNC/laser cutting
- Build the prototype
- Crash
- Adjust plans (build out all the nice formers for the more rounded fuse)
- Prepare skin with flattened foam shapes
- Build prototype v2 (the pretty one)
- Fly!
 
#15
I don't think I saw your all up weight in the build thread - any idea how much she tipped the scales at?
So here are some numbers.

330g (11.64oz)- Air frame +servos and linkages
93.7g (3.31oz)- NTM Propdrive 28-36 1400kv
49g (1.72oz)- Hobbywing Platinum PrO V3 50A ESC
195g (6.88oz)- 3S 2200mah Batt

Estimated
AOW
667.7g (23.55oz), call it 700 ready to fly.

Other numbers for reference-calculated
34" wingspan gives 170 sq. in(11sq. dm) wing area
wing loading- 19.91 oz/sq ft (61g/sq. dm)
Cubic loading- 18.32 oz/cu ft
Stall speed 22.1mph (35.6km)

I cant imagine one being built this size being much lighter. I thought maybe my foam turtledeck could have been kinda heavy but I weighed it and it only amounts to 44g. I think if i were to rebuild out of balsa and fiber glassed foam the weight would be closer to 900g although it would be much more durable.
 
#17
Plans progressing along...

While I started the outline on InkPad (iPad app) I moved over to Inkscape for the next phase of work - figuring out the foam shapes. I figure the prototype will be a little rougher - not worrying so much about the rounded top for instance. Mostly need to see if the proportions will fly. For example, I extended the control surfaces to the edge of the structure (instead of just a smaller control flap). Want to see if it will fly, or if I need to adjust, before I make the pretty one.

View attachment 73517
Looking good!
 

rockyboy

Skill Collector
Mentor
#18
Back into this project again (after a few distractions) - finished layout out the upper lid, fuse formers, and arranging everything for cutting on a 18x24 laser bed. A little concerned about the tail being weakened by the addition of a joint in 3 of the surfaces. I staggered each of the joins to help, and we'll just get to see how it goes. The fuse panels are just a little longer than a full sheet of foam board anyway, so it's going to get a joint somewhere.

I haven't worked out the poster board parts yet, but I'm thinking I'll just rough something in for the prototype.

caudron c.463.png

To do:
- Cut the foam and plywood
- Build the prototype
- Crash
- Adjust plans (build out all the nice formers & posterboard for the more rounded fuse)
- Prepare skin with flattened shapes
- Build prototype v2 (the pretty one)
- Fly!
 

rockyboy

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Mentor
#19
Heading off to the laser cutter tonight with the current sized plans. I figure I'll learn a lot putting it together now, even though I will need to bring the next prototype up to full 1/6 scale for the contest rules. The current wingspan is about 4" short. I really hope the wings will still fit in the laser cutter's 18x24 bed after the change.

I also found a really interesting document in the NASA archives - NACA Technical Memorandum #765 - The 1934 Contest For The Deutsch de la Meurthe Trophy. It's a great read to get a better feel for the spirit and experiences of the era. Very big file to download though.

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930094652.pdf

It includes a lot of stuff in the Pilotage section like "During the first trials Delmotta, strapped to his seat by an abdominal belt, struck his head several times on the ceiling of his cabin. Subsequently the Caudron pilots used an Aviorex belt, whose 5 straps divided the strains more evenly . Seats with side cushions should be equally advantageous also for holding the pilot in his seat."

Also has specific commentary on the race manouvers - benefits and drawbacks of the turn styles, pilot prep and training info, etc. Very cool!