FF2017 Int. Racers: Caudron C.460

[rockyboy]

So here's the 33" Caudron - or v3 as I call her - nestled in with all the other things hanging from the shop ceiling.



And a close up of the reinforcement in front of the firewall to help her be more cartwheel resistant. :black_eyed:



And the wing for the 44" v4 being pressed while the glue dries...



I hope to have her all done this weekend - not going to be able to get out to fly due to family stuff, so might as well build!

 

[rockyboy]

Very productive building day! Here's the 44" Caudron - fourth in the series - ready to go!



And here she is hanging in the shop in front of the 33" one. That extra 10" of wingspan sure makes for a much larger airframe



Due to family trips and events, it's likely to be at least three weeks before I get a chance to fly them.

 

[wilmracer]

Very productive building day! Here's the 44" Caudron - fourth in the series - ready to go!

View attachment 88468

And here she is hanging in the shop in front of the 33" one. That extra 10" of wingspan sure makes for a much larger airframe

View attachment 88469

Due to family trips and events, it's likely to be at least three weeks before I get a chance to fly them.

Looks great! I'm looking at 2-3 weeks before having another go with the P-40 so I moved on to focusing on my Caudron build. If I can get mine wrapped up maybe we can maiden them together. I think I've got the last of the stuff I need for this build. Picked up some XT-90s and I'll redo a high C rated 4s 4000 with them. I think one of the issues I've had with the nn-P38 is way over-running the amp rating of the deans connectors and I don't want that here. For the racing I'm thinking I'll be pushing 70-80Amps through the entire race and I don't want to have an issue getting the power to the motor.

Next time we meet up I hope to have a little something for you for v5 too

 

[rockyboy]

Next time we meet up I hope to have a little something for you for v5 too

v5?

I haven't even crashed v3 yet!

 

[wilmracer]

So now that we're in the countdown to the races I need to get on this Caudron ASAP. The T-38 project is on hold for a few days while I get all signed up at a "local" field with a paved runway, and the P-40 is patched (again) and ready for another go... so its time to build!

As I noted earlier I'm planning on doing everything I can to squeeze as much performance from this design. The plan had been to go with a full Nerdnic speed wing, but after some thinking I decided to hotwire some racing wing cores. Now that I've got my templates and blanks cut making more wings is honestly pretty quick. Not AS quick as DTFB, but I think the tradeoff will be worth it.

I'm using an airfoil that is used in F5D electric pylon racing and is friendly to flaps. I'm probably skipping flaps on this one but if it looks like she really needs them they could be added. THIS AIRFOIL is the one I'm going with.

The cores were cut from 2" insulation foam, CF tow was added to the surface, and then using the beds as a base 2mm depron was laminated onto the core. I could have cut the servo wire channels before laminating but I'm still working out servo location and control surface size/shape. Once covered with low-temp covering my channels wont be visible anyway so I'm not worried.

When cutting the cores I added about 3mm of washout to help keep the stalls manageable. I THINK that ideally pylon racers have no dihedral, but I'll be adding a bit anyway. Everything is a trade off but I want this thing to race well but still be manageable to fly in non-race circumstances.

 

[rockyboy]

That looks awesome!

 

[Mid7night]

Hey, no fair using real AIRFOILS!!

 

[wilmracer]

That looks awesome!

Thanks! I need to cut a few more blanks this weekend and then I'll cut you a set of wings for all your effort on this model (if you want them of course . Not sure if you're sick of Caudrons yet ) Cutting and laying up the panels is actually pretty quick once you have everything laid out. Obviously still have to cut and shape the wingtips but that is pretty straight forward.

Oh, and I had a thought about your flap conundrum. Toss some fixed gear on it and tell everyone it is a Caudron c362!

Hey, no fair using real AIRFOILS!!

I remember a heated conversation about how, technically, everything is an "airfoil" if you build a wing out of it. Some are just a bit more efficient than others and this one just happens to be used by guys doing competitive electric pylon racing

 

[willsonman]

The rules of the races do not specify that the aircraft needs to be built per the plans. In fact, there are NO RULES around the construction other than the entry must be a subject of the design-off. As they are the inspiration... ANYTHING GOES!

 

[Mid7night]

I remember a heated conversation about how, technically, everything is an "airfoil" if you build a wing out of it. Some are just a bit more efficient than others and this one just happens to be used by guys doing competitive electric pylon racing

LOL yeah, if it's on a wing, it is by definition the airfoil of that wing, even if it's a flat plate.

 

[AircPirateNinsei]

Here is a card for this plane:


Download: View attachment Card_Caudron_C_460.pdf

For more cards take a look in this Thread: http://forum.flitetest.com/showthread.php?34748-CARD-GAME-Foam-Board-Planes

 

[rockyboy]

I love the card! Thank you!! :applause:

And yes - I'm absolutely interested in a set of foam core wings - right now I'm averaging about 5 flights per Caudron, so chances are high they will get put to use this summer

The primary difference between the Caudron C.450 and C.460 models were fixed vs. retractable landing gear. I've got to do something to address the hand launch risk on this bird - I've been thinking bungee launch system but might have to go for wheels. Our rough field is just a killer though, and I'd like to keep her from needing a rolling takeoff if at all possible.

 

[wilmracer]

I love the card! Thank you!! :applause:

And yes - I'm absolutely interested in a set of foam core wings - right now I'm averaging about 5 flights per Caudron, so chances are high they will get put to use this summer

The primary difference between the Caudron C.450 and C.460 models were fixed vs. retractable landing gear. I've got to do something to address the hand launch risk on this bird - I've been thinking bungee launch system but might have to go for wheels. Our rough field is just a killer though, and I'd like to keep her from needing a rolling takeoff if at all possible.

You'll get her dialed in eventually. I think of these as a lot like the issues I had with the Rare Bear at the beginning. They are very similar airframes in terms of "small" size, high wing loading, high-power setups. They need a REALLY strong toss and a locked in CG. I ended up putting some rough sandpaper on where I gripped the rare bear so you can really grip it and I'm planning the same with my Caudron. Giving yourself a CG you're confident will be nose heavy and then working back from there may help too.

 

[DamoRC]

They need a REALLY strong toss and a locked in CG.

I concur - a good strong chuck is needed and I was routinely setting her up at about 10 degrees nose heavy when I balanced her on the CG marks. I think part of the reason I killed mine was complacency - I had four good flights before FFW and a few at FFW and thought, "sure, this thing is no problem" and eased up on how hard I threw it that last time.

DamoRC

 

[rockyboy]

Thanks for the feedback - as the pilot with the most succesfull flying time on this design, it's an extremely valuable gift!

 

[wilmracer]

I got a bit more done on my build over the weekend.

• Wingtips installed and shaped
• Wing panels joined and dihedral set
• Fuselage construction about 75% complete
• Wing and empennage installed
• 1/16th Ply battery tray installed. I am skeptical that foam would hold the 4s4000 mAh pack under high G loads.

Because it seems I can never build a plane 100% to plans I've decided to make a few SMALL adjustments to the fuselage. I'm hoping to knock this out the next two or three nights

• Added additional foam doublers in areas to allow for sanding/shaping before covering
• Modification to the hatch. I will be permenantly mounting the upper fuse area behind the cockpit. The servos will be installed in this area to allow for short linkages. Hatch will separate just aft of the cockpit when complete.
• Plan is to use 2mm depron rather than posterboard to sheet the hatch sections. Formers have been adjusted to allow for the additional thickness of the skin.
• A set of servo fairings will be used for the ailerons, which will protect the servos and linkages on belly landings. I have a set that came off of a rare bear wing that I killed at FF last year that will work perfect.
• Planning a 3D printed cockpit. Once I have the hatch done I'll grab the measurements. I'm not certain if I'll use the 3D printed frame or if I'll print a solid one and use it to make a plug for pulling clear canopies. That is TBD.

 

[willsonman]

Awesome work, Carl!

 

[wilmracer]

Awesome work, Carl!

Thanks!

One thing I left off above... Never having done any pylon racing myself I've been doing some reading on pylon racer design, construction, and techniques. There were some interesting thoughts on control surface sizing, placement, and throws.

For starters aileron placement is a balancing act between minimizing drag and other considerations. I'll probably be moving my ailerons inboard a bit as it seems this will help reduce low speed snaproll tendencies and will allow more tolerance in servo centering. I'm using HS65MGs which should be good enough, but if your high speed throws are only a few mm any slop can make these things squirrelly.
Inboard ailerons are also thicker in cross section which can allow for stronger hinging and less risk of flutter. I'll be using a combination of slot hinges and monokote hinging for gap-less hinging.

According to one ranked pylon racer's notes you only need enough elevator throw to do a smooth 75' loop and only enough aileron to roll 360* in 2 seconds. I'm still working out the actual throws but I'll be using tons of expo to help keep things nice and smooth.

 

[willsonman]

FWIW I've been using 60% expo on my racers... and no gyro

 

[wilmracer]

Knocked out some more last night. All servos installed and surfaces hooked up. My ailerons are small. Normally I'd go larger for more roll authority at slower speeds, but I expect this one won't see the south side of 70mph except on takeoffs and landings. There is LOADS of authority in the rudder so slower flight may need to make use of it, but I think she will be perfectly manageable.

Aft servos are installed into a 1/16 ply plate, hotglued in, and then secured with screws. Maintenance will require surgery, but I went with metal gear servos in the hopes that it will never be needed. The only slop in the linkages is a result of the plastic control arms. I dont have any heavier or metal arms that fit the HS65MGs.

Ailerons servos installed into flush pockets with hot glue and the wiring run in a small slit in the underside of the wing. I'm using Typar house wrap tape, which I find is a bit like packing take on steroids, for my hinging on the ailerons. There will also be a top layer of the low-temp covering over the hinges. I did the same with the nnP-38 and the hinging holds up great to abuse. Not worried about them at all.

I hope to get some time this weekend to wrap up the airframe. There really isn't a TON left to do. Firewall, forward fuse, hatch and latching. I need to swap out the XT-60s for XT-90s on a pack or two and on the ESC as well. Don't want the XT-60s dying under 4+ minutes of 80ish amps.