# Four new rockets - one new question

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#### sandman

##### Well-Known Member
Don't forget the Aerotech F21 Single Use motor!

24mm by 3.75" Fits into an Estes "E" motor mount.

If you can find 'em.

sandman

#### NewEntity1

##### Well-Known Member
I'm putting the Big Daddy together with plain 'ol yellow glue, and I'll be strengthening the fins a little with filler, but they are still just balsa fins...

...I don't think it would survive an F, and a G would turn it into itty bitty rocket confetti

#### sandman

##### Well-Known Member
I'll be strengthening the fins a little with filler, but they are still just balsa fins...
That'll make 'em strong enough to survive an F21 motor!

sandman

#### powderburner

##### Well-Known Member
Originally posted by rocwizard
wouldn't it make more sence to do a 4-E cluster since it has 4 fins?

I think you are dead on, it definitely would make more sense from a configuration standpoint, it would make it much easier to nestle those four motor tubes amongst the four fin roots.

OTOH

Four E motors at once is definitely in the range of $20 per flight (did I tell you how cheap I am?), a slippery slope on the way to high-power hell. Myself, I could fly it once or twice but it would probably get retired after that. I kind of start choking at the$10-per-shot level, and like to keep things closer to that (maximum) expense.

#### powderburner

##### Well-Known Member
Originally posted by NewEntity1
Putting an E9 in a motor mount meant for a D12 woud leave the motor hanging out the end a fair distance, which isn't critical, but is kinda ugly looking .
You might get away with this, ugly or not, but you should definitely check for stability with this motor.
The E is not only longer, but heavier, and the extra length hanging out the rear moves the motor center-of-gravity significantly aft. All these things are BAD. Let me repeat, BAD.

Definitely run a sim, or swing-check, or both. Or have a good bunker handy near the launch pad.

#### powderburner

##### Well-Known Member
Originally posted by sandman
Don't forget the Aerotech F21 Single Use motor!
24mm by 3.75" Fits into an Estes "E" motor mount.
If you can find 'em.
sandman
I haven't seen anywhere to get these for a good price these days, AT does not seem to have gotten around to making any more before running into trouble again.
Any tips?
Who has 'em?
Who has 'em cheap?

#### sandman

##### Well-Known Member
Hey, don't look at me!

As far as I'm concerned the F21's are just a rumor...I've never seen one yet.

sandman

#### rbeckey

##### Well-Known Member
My V2 is begging for an F21. I can't find one either.

#### Stones

##### Well-Known Member
Originally posted by sandman
...As far as I'm concerned the F21's are just a rumor...I've never seen one yet.

sandman
The F21 is the 1st composite I flew when I got back into rocketry. Nice and loud with alot of smoke. I still have a dozen or so of them.

#### powderburner

##### Well-Known Member
Originally posted by Stones
I still have a dozen or so of them.
Let's all go over to Stones' house

#### NewEntity1

##### Well-Known Member
Originally posted by sandman
As far as I'm concerned the F21's are just a rumor...I've never seen one yet.

sandman
Lol --However, they fired off TWO of the buggers at the launch I went to on Dec. 7th

Meanwhile...isn't there a new Econojet SU call the F20-W? Aerotech has it listed on their website, but the webpages of the retail distributers didn't have it listed yet, last time I checked...

Opps my bad...the F20-xW is a 29mm SU, not a 24mm.

#### rabidsheeep

##### Well-Known Member
best thing ive done with a big daddy was fixed my friends after the kid stepped on it...

#### BlueNinja

##### Well-Known Member
Trying to post pic of E30, yes that is a GBA SP next to it.

#### sandman

##### Well-Known Member
Blue_Ninja_150,

I'm not seeing a picture.

I noticed that it's a bmp file.

Try saving it as a jpeg and downloading it that way. jpegs are smaller than bmp files.

sandman

#### BlueNinja

##### Well-Known Member
ok, will try that. How's this?

#### astronboy

##### Well-Known Member
I have a few 24mm F21s floating around here somewhere. I bought 8 at once when I found them and am glad that I did. I fly my Maxi Brute V2 with them, and I just LOVE this motor.