XB-70 Valkyrie: FT Style

[Mid7night]

Yup.

This is me posting my intent to build a foamboard Valkyrie.

Let's get right to the model overview...

Wingspan: 5.5ft
Length: 9.7ft
Power: 6 x 70mm EDF
Battery: 4S (lots of them)
Estimated weight: ~20lbs

Features: Folding wingtips, retractable landing gear, awesome jet sound

Modeling Constraints: All foamboard, as little of anything else as possible (wood, carbon, etc)

Oh yeah, and SIX DUCTED FANS!!!



The spirit of this project is to build a crazy giant jet, but do it using Flite Test building and modeling techniques at every possible turn. That means minimal round cross-sections, a few curved surfaces but not too many, and simple fold-over foam spar wings. Yeah I'll probably have some paint-stick reinforcement for the landing gear retracts, and the retracts themselves are going to be a bit more than "FT style", but the spirit will remain. The wing loading should be low enough that I shouldn't need ANY carbon rod or stringer reinforcement, but we'll see once I really get into things.

Because of that spirit, I reached out to Flite Test and asked if they wanted to be along for the ride, maybe even partner or sponsor me in some way. Long-story-short: Flite Test is absolutely on board. I'll share more what that means as it becomes appropriate, but suffice it to say they are the sponsor helping me bring this project before a larger audience, and inspire as many people as possible to dream and build big, even in foam!

To further kick things off right, I made a simple chucker-glider mockup for testing out CG placement. Well, it turns out to be a ridiculously fun chuck glider all by itself! So I'm posting my simple 1-sheet plans for that here right off the bat.

Download the glider plans here!: View attachment FT-70_chucker_v5_PDF.pdf




I WILL also be sharing my full-scale plans for the big bird as I go along, but those aren't ready for prime-time yet.

In the meantime, sit back, relax, and go build a mini-Valkyrie of your own! Stay tuned here for more updates as I gather parts, print plans, cut foam and start to piece together this BEAST!

I will also be posting periodic updates on my vlog channel, so be sure to check there as well: https://www.youtube.com/benharber

 

[Mid7night]

Kickoff announcement video, with video of the little glider!

Quick time-lapse-style build video of the little glider, and clips of my dad and my son flying it!

 

[Mid7night]

Parts List:

3 x Receiver: https://alofthobbies.com/frsky-x8r-8-16-channel-receiver.html

4 x UBEC: https://alofthobbies.com/6amp-ubec.html
(also used to power wingtips and retracts)

5 x Rx Batteries: https://hobbyking.com/en_us/turnigy-nano-tech-950mah-2s-25-50c-lipo-pack.html
(also used as aux. power for wingtips and retracts)

12 x Control Servos: https://store.flitetest.com/tough-tilt-servo-es3154-emax/

2 x Wingtip Fold Servo: https://alofthobbies.com/power-hd-1501mg-metal-gear-servo-15-5-kg-215-oz-in-16-sec.html

6 x Battery Voltage Sensors: https://alofthobbies.com/frsky-sp-flvs-smart-port-lipo-voltage-sensor.html

1 x Airspeed Sensor: https://alofthobbies.com/frsky-airspeed-sensor-spass-70-167mph-rated.html

2 x Main gear retract: https://hobbyking.com/en_us/all-metal-servoless-90-degree-retract-for-large-models-10-12kg.html

1 x Nose gear retract: https://hobbyking.com/en_us/all-met...ng-nose-retract-for-large-models-10-12kg.html

3 x Landing gear struts: https://hobbyking.com/en_us/turnigy...-oleo-strut-with-trailing-link-170mm-2pc.html

10 x Wheels: https://hobbyking.com/en_us/turnigy-scale-jet-alloy-wheel-54mm-w-rubber-tire.html

6 x EDF Units: https://www.banggood.com/FMS-70mm-1...5-KV2750-Motor-For-RC-Airplane-p-1023640.html

6 x ESCs: https://hobbyking.com/en_us/hobbyking-85a-blueseries-brushless-speed-controller.html

6 x Batteries: https://hyperion-world.com/en/p2602328-hp-g550-5000s4-13804

 

[Mid7night]

Reserved for unknown unknowns

 

[Michael9865]

Awesome project. It has been a popular airframe lately.

 

[willsonman]

Really looking forward to this, Ben. I have no doubt that you will have a successful build and maiden. These big projects can be draining so pace yourself and we are here for your support!

 

[foamtest]

I saw the title and read the first few sentences and I instantly subscribed. I can't wait to see how this turns out!

 

[jaredstrees]

Subscribed. Looks awesome and I am looking forward to seeing this beast come together!

 

[SP0NZ]

Sub'd!

You got this Ben! I can't wait to see it, and more importantly...HEAR it! This thing is going to make some NOISE! :applause:

 

[jhitesma]

Love the XB-70! And I bet my daughter will love the chuck glider.

Can't wait to see how it goes since I don't think there's any chance of collecting 6 EDF's to build my own

 

[LitterBug]

Love the XB-70! And I bet my daughter will love the chuck glider.

Can't wait to see how it goes since I don't think there's any chance of collecting 6 EDF's to build my own

WAY COOL! Love hanging out with the XB-70 at the museum down the road.

@jhitesma, Just need to come up with a way to 3D print some EDFs. I'm trying to come up with something that would work with 110x motors... And I need 8 =-O much smaller edfs for my winter project....

Cheers!
LitterBug

 

[jhitesma]

@jhitesma, Just need to come up with a way to 3D print some EDFs. I'm trying to come up with something that would work with 110x motors... And I need 8 =-O much smaller edfs for my winter project....

I considered that for a few minutes...but...

The duct...no problem. The fan? Scary idea IMHO. I doubt a 3d printed one would hold up. Better to use a 3d printed mold to cast one I'd think. And the big expense is the motor which isn't going to be printed anyway.

I have zero experience with EDF's so far (just got my first one to go in my X-29 but still need an ESC before I can get that going) but my gut is telling me not a great idea to try and 3D print one. Still...interested in seeing what YOU do

Fired up the MPCNC with needle cutter and cranked out an FT-70_chucker for my daughter tonight:



Took about 10 minutes to cut, probably less time than I'd spend printing and taping plans to cut by hand (Yeah, I did spend about 5 minutes on the CAM...but if I make more than one of these it's amortized over all of them. And if it flies as well as Ben's did I can easily see making a dozen or so to bring on one of our camping trips this summer for the various kids in camp to play with.)

If you look close you can probably see the one little T-pin current holding it together. Tomorrow she gets to fire up her glue gun and do the "real" assembly

 

[Mid7night]

Hahaha, that's awesome! SO glad to see another tiny Valkyrie take shape. The CG should work out just with the glue needed to assemble, but I'll be curious to see how it works out for you.

Also, the canard flaps will help it fly a little slower and float a bit, but it flies really good and long with them flush.

 

[Allenhat]

Following this to see where you go Ben. Looks great so far.

 

[jpot1]

So this happened this morning...

Thanks Ben!

 

[DamoRC]

"SIX Duc-ted Fans!" - for some reason I read this and in my mind all I could hear was "FIVE Gol-den Rings" from the Christmas song.

As with all Ben's projects - this is gonna be cool.

Can't wait to see it take shape. Are you planning on bringing it to FFW 2018?

DamoRC

 

[Mid7night]

DamoRC: Yes, taking it to FFW'18 is my plan...wherever that is.

jpot1: That's AWESOME!!! I love that you added a body too. You know people are gonna want added plans for that now.

 

[LitterBug]

I considered that for a few minutes...but...

The duct...no problem. The fan? Scary idea IMHO. I doubt a 3d printed one would hold up. Better to use a 3d printed mold to cast one I'd think. And the big expense is the motor which isn't going to be printed anyway.

I have zero experience with EDF's so far (just got my first one to go in my X-29 but still need an ESC before I can get that going) but my gut is telling me not a great idea to try and 3D print one. Still...interested in seeing what YOU do

I always thought it was scary too. But your 3D printed gizmo that flings props changed my mind... I'm looking at 2"ish which should be less explosive too. Probably use props initially till I come up with something.

LB

 

[jhitesma]

Ohhh...I like that jpot1! Look forward to seeing how it flies!

We got our chucker in the air today and it did well considering the conditions. Little gusty for chuck gliders. It did seem to have a bit of a roll to it which I figured out was due to the canard being canted relative to the wing. Had some issues with the new glue I got my daughter for her mini gun and it was cooling down too quick on us making assembly tricky. So we must not have had the nose pieces lined up as well as I thought. I was able to massage it more or less square and it tosses better. But we're hoping for calmer air tomorrow to play some plane catch.

I always thought it was scary too. But your 3D printed gizmo that flings props changed my mind... I'm looking at 2"ish which should be less explosive too. Probably use props initially till I come up with something.

You're bound and determined to make me regret sharing that project I'll admit those 3D printed props hold up better than I expected...but I have had a few of them blow apart after some hard landings. (Note - using that setup to launch props horizontally instead of vertically is an even worse idea than it sounds like....but a lot of fun )

I'll have to keep an eye on your threads and see what you come up with

 

[Mid7night]

Ohhh...I like that jpot1! Look forward to seeing how it flies!

We got our chucker in the air today and it did well considering the conditions. Little gusty for chuck gliders. It did seem to have a bit of a roll to it which I figured out was due to the canard being canted relative to the wing. Had some issues with the new glue I got my daughter for her mini gun and it was cooling down too quick on us making assembly tricky. So we must not have had the nose pieces lined up as well as I thought. I was able to massage it more or less square and it tosses better. But we're hoping for calmer air tomorrow to play some plane catch.

Awesome! Please take some video if you can, I'd love to see how it flies for others. Did you have to add any weight anywhere to get the CG close? FYI: That mark on the plans is just a suggestion, it's a pretty forgiving setup. I think you could move the CG back an inch or so and get it to float a little better.