finless rocket

Apogee's Newsletter 379 describes the workings and construction of different finless rockets. It is a good article and I want to build one as a demonstration for the Page School rocketry event we have every year. Figure 6 of the article shows ratios of the different dimensions that will yield a stable rocket and is pretty much all you need. However, there is no indication of exactly where to install the motor mount. The motor mount does go into the upper tube but it is not clear exactly where it needs to line up - i.e. does the aft end of the motor mount line up with the aft end of the upper tube, slightly above or slightly below? Looking at Figure 4, it would appear that the motor mount lines up with the aft end of the upper tube, but I'm not sure. Also, there is no discussion of recovery. I don't see why standard parachute recovery wouldn't work, but looking at Figure 4, there appears to be no room between the motor mount and nose cone to fit any recovery system.

I did e-mail Apogee a couple of days ago about this, but no response yet and I have no contact info for the author. Does anyone have any experience with finless rockets or any ideas.

I'm probably making too much of this and should just align the aft ends of the motor tube and the upper tube and just put a parachute in it, which in the end is what I will probably do. But it would be nice to get some feedback first, just to make sure.

Thanks.

Claude

Take a look at this patent . I tried building one based on the drawing a few years ago. It flew just like a rocket without fins usually does.

Remember, Bill, we've seen you fly rockets with fins, too.

Kenn wrote:

Remember, Bill, we've seen you fly rockets with fins, too.

That's true. I wish we could say we've seen you fly a rocket with or without fins.

I've flown a few of those myself!

The patent solved one question - it can take a parachute. However, from the patent it appears that the motor extends below the gap between the two body tubes which is different from the newsletter article - which could simply mean that it doesn't matter.

The patent was filed in 1972 with the inventor listed as W. Kendrick. The newsletter article was written by W. Dean Black and it states that he pioneered the finless rocket in 1964. That probably doesn't matter either since I don't think anyone has gotten rich on finless rockets!

In any event, Apogee did get back to me with contact info for Black and I e-mailed him. We'll see.