Flying F9 *no fins*

[cscott]

Inspired by Dick Stafford's "The Inductor", I've started building a "finless" flying model of the SpaceX Falcon 9.

It's built with stock parts, which is why the fairing shape is a little wonky.  If it works and flys well, I might kit-bash one of the "official" SpaceX F9 models to fly with a gap and no fins like this.

Main body tube is 1" OD, engine tube is 18mm.  Liberal use of epoxy and aluminum foil to attempt to protect the lower induction tube; we'll see how well that works in practice.

Still needs paint to give it that F9 look.  Can anyone suggest a good source of graphics, and maybe some suggestions on making decals?

More pictures at https://plus.google.com/109541946294746531763/posts/iGMxL6CLhSR

[Paper Kosmonaut]

As far as decal making goes: there is very nice decal paper for usage in inkjet printers. It works well but is a little tricky since it is very thin, thinner than regular decal waterslide stuff that comes with model kits.
As for the logos and other stuff: try and use the parts for the paper kit that Alfonso Moreno has made. It is very accurate, just like his models.
The files are importable in apps like photoshop or inkscape.

[Ronpur50]

I have used a similar decal paper to print my decals for my plastic F-9 models.  I also used the graphics from AXM paper models and adapted it for my models.  Since you said your tubes are 1", that would make it 1/144th scale, which is what I used.  I can email you the word file of the sheet I made up if it will help. 

Also, I have never heard of this fin-less model rocket.  How does this work?

[cscott]

Thanks for the graphics and decal tips.  I think I'm going to print the AXM graphics on paper and wrap the tubes with appropriate sections.  Based on my test last night that should work out fine for the main body tube; the payload fairing isn't quite scale so I might have to work a little harder there.

Ronpur50, the way that induction rockets work is apparently a bit in doubt.  One theory says that the tube after the opening just acts as a narrow/long ring fin.  The other explanation has to do with the air mass losing angular momentum as it is sucked into and through the tube.  Probably both effects are at work to some extent.

Dick Stafford's posts, which I linked up top, have more detail including some dimensional guidelines.  There are some guidelines but not hard and sure way to ensure a finless rocket like this will work, so this thing might flip spectacularly on first flight.

[cscott]

Here are some pictures of the completed model, with paper wraps as suggested upthread.

Still hasn't flown yet!  Timing didn't work out on the launch day I'd planned.

Working on a flying falcon heavy now!

[cscott]

Launched this one on a test flight this past weekend.  I ran out of B engines, so I launched it with an A8-3 which (not too surprisingly) turned out to be rather underpowered.  It was a rather small field, though, so I wanted to be safe.  It traced a nice low arc, but didn't *seem* to be unstable.  Hard to say, I'll have to launch it with a B or C next and see what happens given a bit more thrust.

It did snap its elastic shock cord clean in half, so it's a good thing it didn't get higher than 50 feet or so!  The rocket exhaust didn't scorch the top of the induction tube at all (I was worried about that!) but it did delaminate the aluminum foil from the bottom half of the induction tube.  The cardboard behind the foil looked to be in good shape, though, perhaps the aluminum foil down at the bottom isn't strictly needed.

In any case, I need to come up with a better shock cord mount and do something about the frayed flaps of foil in the induction tube before I fly it again.