Ben Harber's (Gigantic) XB-70 Valkyrie Build!

by FliteTest | November 14, 2017 | (6) Posted in Projects

It's not every day that you hear about someone making a giant scale RC airplane of a XB-70 Valkyrie. When we hear about a truly remarkable project that someone in the Flite Test community is undertaking, we want to shout about it. Recently, we came across Ben Harber's latest marathon build. I checked in with Ben to see how it's coming along.

Here is Ben with Josh Bixler at Flite Fest East 2017. 

An Introduction to the Project

Ben is in the process of building a gigantic model of the North American XB-70 Valkyrie. Primarily, it's to be made with foam board and simple FT building techniques. He's trying to push the limits of what can be achieved with these methods that all of us use to build our, somewhat smaller, FT designs. The design will be a whopping 9.7ft long - as builds go, that's pretty crazy!

During the early phase of the Cold War, the XB-70 Valkyrie was built as a supersonic prototype for a strategic bomber to be used by the United States Air Force. There's little doubt that the aircraft had some interesting features which allowed it to fly in excess of Mach 3 at 70,000 feet.

"It all came together in the CAD model" explained Ben. "I did do a lot of thinking through things as I designed the plans". As you can see from the mockup drawings below, this epic aircraft will be using 24+ sheets of waterproof foam board.

The CAD designs for the 9ft Valkyrie were drawn from standard 3-view drawings, a practice used by many other community members.

This was then made into a 3D model. Check out the crazy spec of this thing.

Chuck Glider Model

Ben has started the Valkyrie project by constructing a small chuck glider model. It's a model of a model! He has provided links to the plans in the main forum thread for the Valkyrie build so you can make one yourself. 

A Short Interview 

I talked to Ben about the project to delve deeper into his motivations and how it's all going to come together. Here's the interview: 

Q: What made you choose the XB-70 Valkyrie for this project?

A: After doing the C-17 in early 2017, and flying it at Flite Fest West '17, I wanted to tackle something bigger and I considered just doing a Bigger C-17, but that seemed boring. The XB-17 had always been an iconic aircraft, and when I ran through my brain-catalogue of other possible "big jets", the Valkyrie was top on the list. It also has a few notable features that I thought would be fun to attempt; mostly the folding wingtips. 

Q: Tell me about how you came to the decision of making this build a simply gigantic size!

A: Well, it actually is smaller than I had originally planned when I began modelling it! Again, coming off the C-17, I was thinking "how big can I go?". One of the largest common EDF sizes is 120mm, so I chose that to start with. I Then looked up the fan-diameter of the turbojets in the XB-70. [...] This made my first version sixteen feet long, with almost a ten-foot wingspan! When I realistically considered that scope, I dialled it back. 

Q: Where are you going to store the aircraft when it's fully built? I'm sure many readers are dying to know.

A: Haha! Yes, I think my wife would like to know the answer to that as well... we don't have a garage or even a second room in our small space, so my father (who lives nearby, and joined me at FFW'17) Kindly offered the ceiling of his garage. It already has an old 9ft rocket of mine hanging there as well. My dad rocks. 

Q: Talk us through what sort of design considerations had to be taken into account for a plane of this size. Surely features like wing spars are crucial?

A: Wing spars are essential, for sure, but an interesting difference with the Valkyrie is how short its relative span is. The main strength of the wing is in its skin, and the spars primarily serve the purpose of just keeping the skins "apart" and holding the wing's shape. For such a large Bird, it actually doesn't have a great wingspan. It has a ton of wing area, but it does so with a low aspect ratio (AR). [...] Also, the under-body (where the engines and inlet are) is quite wide and spans a good section of the center of the wing, acting as sort of an "under spar" support for the wing. One area that will definitely need specific reinforcement is the landing gear attachment. I will be reinforcing that area with some wood spars (paint sticks) so that I can effectively transmit the gear load into the entire airframe. 


I for one am very excited to see this project unfold. If you'd like to keep up to date with Ben's project, check out the XB-70 Valkyrie thread on the Forums here

Here at Flite Test, we love sharing projects like this with the wider community. It shows what can be achieved by anyone willing to put in hard work, time and determination. It's these kinds of undertakings that are indicative of the ambitious spirit alive in the FT community across the world. 

Check out Part 2 of this article series here to keep up to date. We can't wait to see more from Ben as he continues with this epic build.


Other Projects to Check Out

Here's another of Ben's current designs, his twin ducted fan F-4 Phantom

Here's a video of the Phantom maiden flight!

If you liked this article, check out some of the other mega projects from our archives and our community below: 

- 400th episode supersized FT planes!

- Flite Fest Square Plane

- XXL Nerdnic P39 (on the FT forums)

-10ft Ford Trimotor (on the FT forums)


Article written by James Whomsley Editor

Instagram @jameswhomsley


Air-headed Aviator on November 17, 2017
My Goodness Ben! I. Knew about your project but I didn’t know it would be super huge! Whenever the next Flite Fest is I have to go to see this in person.
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jtuttle11 on November 24, 2017
Unhappily the B-70 never made it beyond the prototype and testing phase and only two were ever built. During a formation flight for photo session the B-70 suffered a 'Mid-air' collision which severed one of its Vertical fins causing a catastrophic loss of control and crash of the aircraft.
The crew egress pod system proved to be a FAILURE and neither of the crew survived.
Thus ended the Valkrye project.
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ignafiltro on November 19, 2017
Any more info on the EDFs other than 70mm?
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thenated0g on November 17, 2017
Love all these big builds!
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Oske on December 18, 2017
Looks like I have some competition. I am also working on a simple valkyrie build from foamboard, doing a prop in slot instead of EDF.
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Ran D. St. Clair on November 19, 2017
It's a great subject. I had considered doing a big build with 1" Styrofoam and pusher props. A big EDF build is going to be super cool, but expensive and intolerant of mistakes. Best of luck to you.
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Ben Harber's (Gigantic) XB-70 Valkyrie Build!