Lightest Level 1 rocket?

The best I've done is 20.5 oz H268 ready to fly less the added weight for optimal mass.

Hi, I am assuming that this would be for max speed and / or max altitude? For max speed you want the rocket as light as possible, but I don't think a rocket with an empty weight of 8oz could hold up to a mach+ flight. It would be pretty hard to do. With those motors mentioned, it's kind of a pointless exercise for max altitude, as optimal altitude would be achieved with a heavier rocket in order to take advantage of stored momentum (stored momentum is greater than the negative effects of gravity). Aerotech used to make/makes a H45-15 single use and Ellis MTN makes a H50, and H48 single use. They are still certified if I recall. They weigh in at 10oz. BUT, the H45 is a full 320ns, not 180ns or 220ns. You could probably build a 6oz rocket with these and have it hold up to the flight. Then the problem would be finding them! Daniel

snipped-for-privacy@sct.org wrote:

Mine was about 20 ounces with motor. RMS-29/180 H128W

-Fred Shecter NAR 20117 (L1)

Daniel,

No, you missed my point.

I don't want to design for either max speed or max altitude. I was wondering about the lightest weight rocket you could build designed for an Level 1 CERT FLIGHT.

To give you some more detail of what I was thinking, I was wondering if it would be possible to fly a Level 1 cert flight with a rocket that was designed to fly without requiring FAA notification or waiver (less than 113 grams of total fuel and less than one pound total weight). That's the reason I gave those specific L1 type motors; they all have less than 113 grams of propellant.

And since it would be a cert flight, the rocket must be able to be recovered safely and must be in good enough shape to fly again.

So far, I'm thinking that without using "exotic" materials (like carbon fiber and G-10), something like a slightly strengthened "Big Daddy" (stock weight about 5 oz., modified weight about 8 oz.) might do it.

And, just so you know, this is more of an intellectual excercise than anything else; I'm already certified L2.

Ric T.

Well, that's the lightest I've read about so far...with the exception of Art Applewhite's saucers, some of those are EXTREMELY light. But I've also read (even on his website) that NAR & Tripoli won't allow them for cert flights.

In doing some Google searches, I came across several construction techniques that MIGHT allow building an L1 cert rocket under 16 oz with motor. One technique involves using balsa stringers (like in traditional model airplane construction) to form the framework for the body tube, covered by Monocote or paper.

My idea is to take a "core" of 29mm MMT tube that goes all the way to the aft end of the nosecone, 2" thick white styrofoam (lighter than the pink stuff) centering rings placed about every 5-6", aft one with a balsa/epoxy laminate to protect it from the motor exhaust, body wrap of "heavy" paper or tagboard, balsa fins reinforced with paper & white glue going thru the wall and into the styrofoam CRs, pink foam nosecone. According to Rocksim, a 3" diameter, 40" long rocket built this way, should weigh just less than 16 oz when loaded with an H128, and go to about 2500', recovering with a 30" chute. I may try doing this later this season, just to see what happens.

Ric

See the rocket I built for the really crappy movie "Amazing Grace and Chuck".

29mm core tube with doorskin plywood centering rings above and below the fins and at the top of the main "tube". Solid foam centering rings elsewhere between core tube(s) and main "tube". main tube made by rolling 4 foot length of 1/64" acft plywood and gluing along small overlap seam. motor tube in core went up about two feet and the rest of the core was BT-80 which started about 9 inches below the top of the motor mount tube and extended a foot or foot and a half above the top of the main "tube". Standard Estes plastic cone on BT-80 (Colossus/Maxi-Alpha in those days) with a card stock shroud between BT-80 and main "tube".

Through the wall fins made from 1/16" acft plywood.

Designed to fly on an F or G motor and it weighed exactly 1 Kg at liftoff.

But it was 5.5 inches in diameter and 5.5 feet long.

A lightweight and smaller model can easily be built with this technique.

-Fred "I hate heavy" Shecter NAR 20117

Well, the easiest way to accomplish this is to buy the Apogee Aspire (29mm, weighs less than 2 oz) and replace the fins with 1/16" basswood brushed with thinned epoxy finishing resin. Or hell, just tissue them maybe. Make them clipped delta and they'll survive mach (I did this with a machbuster). Add an H180 and you are at what, maybe 9 oz liftoff with a small chute? And an H180 may be long enough that you could even trim the body tube and still be stable. A single use H55-10 weighs even less and will stress rocket less.

Well, that's certainly true; I just "Rocksim'd" the Aspire, and it's stable enough with either the H128 or the H55 to fly well.

The problem I see with this (as well as with scratch built, small diameter designs) is that it will go so high on an "H" motor that using it for a CERTIFICATION flight is an "iffy" proposition; unless you're flying from a desert/salt flat site, you'd probably never be able to find it again. I know I've flown small diameter scratch built designs on "E" and "F" motors that have totally disappeared at our launch sites here in the Northwest.

Although (thinking about it some more) with the newest radio tracking transmitters, you COULD put one into even a small airframe like the Aspire, and increase your chances significantly of finding it. I just purchased one that I'll be flight-testing for the first time in May in a large diameter airframe; I've ground-tested it, and it looks very promising. But again, if I were having to do my L1 cert flight as a newbie again, I'm not sure I'd want to complicate things that much...

Ric