Von Braun Ferry Rocket

[SteveNeill]

Has anyone attempted to scratch build a flying version of this iconic rocket?

This is something on my bucket list. Since the spacecraft was design by Werner in 1952 (the year I was born) and growing up on "Man in Space" it holds a special spot in my heart.

I have all the skills and the tools and the shop to do it but I was just curious about past efforts.

My plan is to build it around D engines, have the shuttle plane or Ferry separate to be radio controlled back to Earth.

 

[neil_w]

CP location would seem to be the biggest challenge, what with those ginormous front-mounted wings.

 

[SteveNeill]

All true.

 

[Bat-mite]

Might need a ten-ton weight in the nose.

 

[SteveNeill]

Challenges.

 

[Nytrunner]

Mount the motor up in the body, use "windows" as ducts to prevent the krushnic effect or whatever folks call it these days

 

[aerostadt]

Steve, I tried the WVB Shuttle several years ago. Results are documented here. There was also 2 versions in the NAR Technical report that I believe I mentioned in the thread below.

https://www.rocketryforum.com/threads/wvb-xr-1-shuttle.120565/

 

[SteveNeill]

Thank you so much. I like your approach. And I thought of doing it that way.

I can lathe the form and then mold and from there make the parts out of epoxy glass. Thanks again!

 

[GlenP]

I haven't built one of these yet, but have been inspired by aerostadt's build linked above and have this one on my list. I would probably keep it small and just have the shuttle free-flight glide back. Bonus points if I could get the booster to glide back too, which was the original concept, wasn't it?

link to the NARTS order page for the CMASS Plan Book
https://blastzone.org/nar/narts/store.asp?groupid=92400111811376

I also found a couple of versions of cardstock models that might be suitable for conversion to model rockets with 18mm power, or scale them up for 24mm. I was searching for my son's science fair project last year and not sure where the links are now, here is some info that might help you find them. I think they were on a paper modelers forum, or try that AXM paper rocket site. Here is some info from the PDFs that I found and downloaded.

One was called the Collier's Ferry Rocket by Ferdinando Santandrea, I really like the details on this one, 1/300 scale.
https://www.flickr.com/photos/21308886@N02/sets/72157679381439555/

and the other was called the Wernher Von Braun Walt Disney "Man in Space" XR-1 Space Plane by Mike Vink.

 

[SteveNeill]

Thanks Glen! Very helpful.

I did a little playing around with Open Rocket and with a little cheating was able to get the shape close enough to test it's feasibility. The config is three Es for fun. Haven't decided on a size yet for the body. I've only had the program a couple of days and it's pretty easy to use. Notice the CG location with this config. Someone here was right. Lots of nose weight.

 

[Daddyisabar]

Power and nose weight will not solve all of your problems, but knocking 95% of them off the top ain't bad!

 

[aerostadt]

Power and nose weight will not solve all of your problems, but knocking 95% of them off the top ain't bad!

Daddy originally suggested to me the F24 for my model over the D12-3 and it worked good. Steve since you now have a simulation model it might be possible to see if this model needs some minimum power to come off the rod at enough speed to be stable.

Steve, I really love your graphics. If you have an Open rocket file, I would be interested in getting a copy. There is a part of me that would like to come back to this model. I repaired the original and it is ready to fly again, but I lost interest plus I have other model rocket projects going. If I were doing this again, I would at least come up with something stronger that ordinary paper for the main body shroud. That stuff is flexible enough to wrap around the body, but it "wrinkles" like crazy. I just slapped the wings on the bottom of the glider, but a better looking model would have the wings go through the body tube. Yes, with 3 E-motors in the first stage you will need a lot of forward weight.

Frank Burke had a very large R/C Dyna Soar model that is documented on TRF. It is different than the WVB Shuttle, but it flew and glided very well. Frank makes his models with depron foam and so they are very light.

The paper model that Glen posted looks very interesting, too, but has a lot of forward wing area that moves the CP far forward. Note that the first stage technically has 2 fins larger than the other 2 fins. My model and the CMASS model make all fins the same size. There is a lot information in "Spaceship Handbook" by Jack Hagerty. Some of you might already have this book.

 

[SteveNeill]

Thanks so much! Yes you can have the file. It's a but rough and I cheated the program using couplers to make the shapes. I then added body tubes to the ends and made then very small. But it allowed me to add the fins and adjust their positions. Send me a PM or maybe I can post it here, lest see. Seems that worked.

It's a work in progress I didn't really size it and it sporting 3 E's right now. No shock cord or chute yet.

I saw the Dyna Soar flying. Very tempting. I'm not a big fan of foam but have worked with it a bunch.

 

[SteveNeill]

Still working on the design and found I can trick Openrocket to give me contoured body tubes. Enough anyway that I can print off from the PDF and start cutting Dapron and build a test model.

It took some doing but renaming the transitions can be done and then you add a body tube to that but keep it super thin so it's just there enough to add the fins. Then I adjusted the body tube diameter to deepen the fins into the contour. It's crude but it works.

Right now I have three E12's(or something like that) in there but I'm going to have to work on that a bit more.

 

[SteveNeill]

Better still. I can't seem to get much over 158 feet to apogee so far but I'm not sure I have set the tubes for Dapron. I should be very light with that type of construction. I reduced the size and the ferry itself should be large enough still to get my RC gear into it. There's that nose weight I'll need to achieve the CG.

 

[SteveNeill]

And for fun I've been working on the Luna from Destination Moon.

 

[SteveNeill]

BTW if you guys want to use these files to make your own or improve on them or both I encourage you to do so.

 

[aerostadt]

Thanks for the files, Steve. They are fun to look at. I am not that familiar with Openrocket, but I have used RocSim a lot.

 

[neil_w]

I can't seem to get much over 158 feet to apogee so far

That would appear to be because OR thinks it’s unstable.

 

[SteveNeill]

You think? I mean look at it. But simulation isn't always accurate. Testing will tell more.

 

[mikec]

You think? I mean look at it. But simulation isn't always accurate.

I added 6 oz of nose weight and got a stable flight on the 3xE30s you had in the file. 3x E12-6 looks viable too.

Simulation isn't always accurate but I really wouldn't expect this to be stable without at least 3-4 oz of nose weight. Or you could reduce the span of the ferry wings, that would help.

 

[SteveNeill]

Thank you...I needed that.

 

[neil_w]

You think? I mean look at it. But simulation isn't always accurate. Testing will tell more.

OR was showing stability margin of about -0.5, which is (very) unstable. OR will usually simulate a vertical flight with stability margin of at least 0.25-0.5 (very rough guess); recommended margin for safe flight is 1-2. When OR simulates an unstable flight, it is simulating the rocket tumbling and bumbling, and mostly not traveling upwards.

That's why I mentioned challenge of getting into proper position at the top of the thread; those forward wings are going to pull it quite far forward.

Once the CP/CG relationship is as needed (in this case with sufficient nose weight, as mikec says) the OR simulation will yield a mostly vertical flight, and you'll get a true altitude estimate.

 

[aerostadt]

I put lead weight in the front of the first stage. If the R/C electronics in the glider are not sufficient to bring the c.g. forward enough, lead ballast may be needed in the front of the first stage. This model does have its challenges.

 

[burkefj]

Simething like this you want ultra light construction, foam is your friend, glass and cardboard are not. Imho a 24mm motor model will be too small to have a flyable glider and meet weight. Clusters are heavy and are not helping either. Id want the glider around 20" long at least to be able to see it at a boost altitude, and scale from there. You have to figure out a solid glider mount that releases easily and reliably. Consider the glider construction and what boost speed will be max, look at motors and thrust profiles that will meet that and determine your weight that will work.

 

[SteveNeill]

Thanks everyone for your input and it's all sound advice. Burkefj I've seen your work over the years and you are right. Best would be larger and I had always planned to use Depron. My problem is a source. I'm not finding it in CA too easily. My LHS use to carry it then they could get it anymore.

I'll have to do some more searching outside CA. I'm a long time RC pilot and designer scratch builder. The glider I can get right. The rocket part is newer toritory for me.

 

[burkefj]

Try model plane foam(MPF), its around 5.5mm, more flexy than depron but forms to curves easier. And cheaper.

 

[SteveNeill]

I just tried a simple adjustment in size to 20 inches on the glider, a single 38 mm engine and got nearly 300 ft and better stability with a drop of wingspan.

 

[SteveNeill]

https://www.modelplanefoam.com/index.php/foam1/ Wow. And at a great price too. Thank you so much.

 

[neil_w]

I just tried a simple adjustment in size to 20 inches on the glider, a single 38 mm engine and got nearly 300 ft and better stability with a drop of wingspan.

Again, the 300 ft number is nonsense, because the model is unstable. Overriding the CG forward into the stable region gets you 655 ft. That is still not much because it's incredibly heavy. Your centering rings, of which there are many (by necessity), are roughly 7/16" plywood; the larger ones are almost a pound and a half.

Lighten up those rings, and correct the CG as needed, and you'll get a reasonable sim. I'm not actually sure what you should make those centering rings out of, but Frank certainly does.