Old Design -- Prometheus

[Tau Zero]

Here's one of Craig's "lost souls": my Prometheus design from May 2005 (http://www.oldrocketforum.com/showthread.php?t=173). Attached are my now-standard files with various views :D , PLUS some extremely rare "in the wild" shots! ;)

However, taking a look at the deployment velocities almost 4 years after designing this bird which really "gets up and goes," I think the 12" parachute would be fine for 18mm 1/2A and A flights, but I *highly* recommend using a streamer for B and C flights.

Unless, of course, you don't really want your rocket back. :eek: :rolleyes:

Enjoy!

.

[CPMcGraw]

Here's one of Craig's "lost souls": my Prometheus design from May 2005. Attached are my now-standard files with various views :D , PLUS some extremely rare "in the wild" shots! ;)

However, taking a look at the deployment velocities almost 4 years after designing this bird which really "gets up and goes," I think the 12" parachute would be fine for 18mm 1/2A and A flights, but I *highly* recommend using a streamer for B and C flights.

Unless, of course, you don't really want your rocket back. :eek: :rolleyes:

Enjoy!

.

Since I've built this one myself, I can attest to the "get up and go" part. I get great flights on just an A8-3, which is generally a test engine for first flights. I cringe at what this thing might do on a B4 or B6, and figure it's a gone goose on a C6.

Jay, have you tried simulating a 13mm version? You might get even better performance than the A8.

[Tau Zero]

Jay, have you tried simulating a 13mm version? You might get even better performance than the A8.See, Craig, you *always* think of that option. :chuckle:

Here's a go at the Prometheus with a 13mm mount (note the CR-510 centering rings :cool: ).

This design approaches 300 feet on 13mm A motors, which is slightly better than ~225 feet on an 18mm A motor.

"Your sky mileage may vary." :eek: :rolleyes:

.

[CPMcGraw]

See, Craig, you *always* think of that option. :chuckle:

Here's a go at the Prometheus with a 13mm mount (note the CR-510 centering rings :cool: ).

This design approaches 300 feet on 13mm A motors, which is slightly better than ~225 feet on an 18mm A motor.

"Your sky mileage may vary." :eek: :rolleyes:

.

I had a feeling it was a good candidate for 13mm power. You know, of course, this means it gets added to the list... :D

Those are good numbers for the 1/2 A3 and the A10. I will have to build this one.

[JRThro]

See, Craig, you *always* think of that option. :chuckle:

Here's a go at the Prometheus with a 13mm mount (note the CR-510 centering rings :cool: ).

This design approaches 300 feet on 13mm A motors, which is slightly better than ~225 feet on an 18mm A motor.

"Your sky mileage may vary." :eek: :rolleyes:

.
Hmmm... I might have to build the Prometheus kit you gave me w/ a 13mm mount, Jay.

That would stop me from loading the wrong B or C motor in there, and having the rocket drift away, or stripping the parachute and losing the rocket to impact damage.

[JRThro]

Hmmm... I might have to build the Prometheus kit you gave me w/ a 13mm mount, Jay.

That would stop me from loading the wrong B or C motor in there, and having the rocket drift away, or stripping the parachute and losing the rocket to impact damage.
I built it last night with the stock 18mm mount, but I might make an adapter for it to use 13mm motors.

I wouldn't hold my breath, though. I'll probably just fly it on A8-3's for now.

[Tau Zero]

Jay, I have a set of Prometheus fins, already papered and CA'ed, if you need them... No, wait a second, I need those to build the Prometheus! :eek:

I guess you'll have to ask Carl after all. ;)Yeah, 'cause I cut, sanded, label-papered, and CA'ed all but the root edges... for *you.* ;) :chuckle:


I built it last night with the stock 18mm mount, but I might make an adapter for it to use 13mm motors.

I wouldn't hold my breath, though. I'll probably just fly it on A8-3's for now.That'll get you *plenty* of performance! :eek: :cool:


Enjoy!

.

[JRThro]

Yeah, 'cause I cut, sanded, label-papered, and CA'ed all but the root edges... for *you.* ;) :chuckle:
I know, and I really appreciate it! You did a *far* better and cleaner job than I would have, I'm sure. Those fins look like they were cut/sanded/papered/CA'ed by machine or something, because all three fins are all *exactly* the same size and shape, which is something I can never get exactly right. Plus, the edges are all flat and perpendicular to the faces of the fins.

(Even ignoring the fact that I've never label-papered a fin.)

Right now, I'm filleting the fins with Elmer's white glue, and then construction will be complete except for the parachute. My club had a launch scheduled for this weekend, but it was rained out both yesterday and today, so we're shooting for next Saturday. That'll give me time to complete the building of the Prometheus and a couple of other rockets I'm working on.

[JRThro]

I flew the Prometheus at our club's rescheduled launch yesterday.

It was primered but not painted just yet.

Very nice! Perfect flight on an A8-3, perfect recovery, no damage at all.

[Tau Zero]

I flew the Prometheus at our club's rescheduled launch yesterday.

It was primered but not painted just yet.

Very nice! Perfect flight on an A8-3, perfect recovery, no damage at all.John,

Just wanted to get an update. Did you paint yours, or did you have any additional comments on this design?


"Inquiring minds want to know." :eek: ;) :D


Cheers,

[A Fish Named Wallyum]

More wilderness shots. :rolleyes:

[Tau Zero]

More wilderness shots. :rolleyes:*Nice!* I had the first two, but not the third one. :cool:

After extensive RockSim testing today, I confirmed that Prometheus owners will *definitely* need streamers on B and C flights, due to chute-shredding velocities. :o

OTOH, a 1.75X SLS Prometheus would be just fine with a 24" chute on C through G motors. :eek: :D ;)


Cheers,

[Tau Zero]

More wilderness shots. :rolleyes:Hey Bill!

What are the dimensions of that streamer? It appears to be Just About The Right Size. ;) :D


Cheers,

[A Fish Named Wallyum]

2.5" x 36"

[Tau Zero]

2.5" x 36"Thank you, sir! ;) :D :cool:

[A Fish Named Wallyum]

Thank you, sir! ;) :D :cool:

Sorry it took so long, but having it come to mind when I was in a position to check wasn't the easiest thing to arrange. It normally happened at work around 3:30am, but for some reason it happened in the middle of the afternoon yesterday. :o

[CPMcGraw]

Here is the fin sheet for both versions of Prometheus.