Estes Fat Boy question
Helen Rapozo
On Wed, 7 May 1997, Kevin Boorn wrote:
> Has anyone uprated a Fat Boy to take D or larger motors?
> If it's possible or been done, what additional mods are required?
>
Nope, mines still flys on B/C engines. If you do mod it for D
engines, you should use a 12" chute instead of the 18" chute. It
kind of drifts when flying on C engines with a 18" chute.
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Kevin Boorn
Has anyone uprated a Fat Boy to take D or larger motors?
If it's possible or been done, what additional mods are required?
Kevin Boorn
Steven C. Smith
Kevin,
Jack Wiker, a member of NIRA (NAR Section #117) converted his Fat Boy to
accept not only a 24mm 'D' size engine but 3 18mm 'C' size engines as
well.
However, things didn't go to well on the first flight, I believe Jack
said that it core sampled.
Steven C. Smith
NAR #69210
Member: NIRA (Northern Illinois Rocketry Association)
wo...@eda.mke.ab.com
In article <BPrwNMAm...@kboorn.demon.co.uk>,
Kevin Boorn <ke...@kboorn.demon.co.uk> wrote:
>
> Has anyone uprated a Fat Boy to take D or larger motors?
> If it's possible or been done, what additional mods are required?
There is a thread going on the CSI Sport Rocketry forum about this. The
typical "beefing up" techniques are used, such as bass or plywood fins,
TTW fins, fiberglassing of the body tube and fins, adding nose weight for
stability. Several have done the 24mm mount modification. But Andy
Schecter has built his with a 38mm mount and plans to fly it with the
AeroTech 38/240 casing with an H123 or H242. Someone else was talking
about using the 38/360 case and flying it with an I161 but there was
concern over the motor length and space for the chute. Anyway, I hope
Andy flies his at NYPOWER, uh, I mean NSL 97, as I'd like to see that
flight.
Dan Wolf
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Jack Wiker
Steven C. Smith wrote:
>
> Kevin Boorn wrote:
> >
> > Has anyone uprated a Fat Boy to take D or larger motors?
> > If it's possible or been done, what additional mods are required?
> > Kevin Boorn
>
> Kevin,
>
> Jack Wiker, a member of NIRA (NAR Section #117) converted his Fat Boy to
> accept not only a 24mm 'D' size engine but 3 18mm 'C' size engines as
> well.
>
> However, things didn't go to well on the first flight, I believe Jack
> said that it core sampled.
>
> Steven C. Smith
> NAR #69210
> Member: NIRA (Northern Illinois Rocketry Association)
It WAS stable, (with added nose weight), but I was air starting the
central E30 engine...and the thermalite chuffed out. No ejection
charge, no chute. I will retry it (with a D12) at MRRF.
Jack TRA 3416
Doug
Kevin Boorn wrote:
>
> Has anyone uprated a Fat Boy to take D or larger motors?
> If it's possible or been done, what additional mods are required?
> --
> Kevin Boorn
Yes, just use a piece of LOC MMT-095 and two CR 2.56-095 centering
rings. It's stable, but you probably want to use a better chute and
shock cord. Plywood or G-10 fins wouldn't hurt either. If you use .031
G-10, you can cut it with large scissors.
Doug
--
After a time, you may find that "having" is not so pleasing a thing,
after all, as "wanting." It is not logical, but it is often true.
- Spock, "Amok Time", stardate 3372.7
Jerry Irvine
> Schecter has built his with a 38mm mount and plans to fly it with the
> AeroTech 38/240 casing with an H123 or H242. Someone else was talking
> about using the 38/360 case and flying it with an I161 but there was
> concern over the motor length and space for the chute.
I suppose you could go I65 54mm and out the chute on the side :)
Converting it to 24mm D/E/F/G power is practical and even when stock (fins
covered with tissue) sufficiently strong for:
Estes: D12-7
USR: D12-8 D24-8 E12-8 E25-8 E50-8 F25-8 F50-12 F100-12 G35-8 G70-12 G140-12
--
Jerry Irvine <mailto:jjir...@cyberg8t.com>
Box 1242, Claremont, CA 91711 USA
Opinion, the whole thing.
The Silent Observer
Kevin Boorn wrote:
>
> Has anyone uprated a Fat Boy to take D or larger motors?
> If it's possible or been done, what additional mods are required?
> --
> Kevin Boorn
I've got one in primer with a 24mm core and 4 18mm outboards. I
calculate it'll need 4 oz of nose weight to be stable with motors in all
tubes, and will actually fly higher with only a D12 in the center mount
and light plugs in the outboards. With a D12 conversion and the other
weight the mount mods added, I'll need an ounce in the nose; that puts
liftoff weight around 6.5 oz, which coincidentally is almost exactly
optimum weight (assuming Cd of .8) -- altitude should be around 375 feet
with a -3 delay ejecting a fraction short of apogee. Oddly, if I put an
E18 reload in the core mount, I'll get around 800 feet, but still only
need a -4 delay -- the extra 400 feet of altitude is almost entirely
during boost, with only about .25 seconds extra coast time...
BTW, I saw a stock Fat Boy with a 24mm mount the only modification flow
last weekend -- flew beautifully, though I don't know how much if any
nose weight it was carrying.
--
A confidence man knows he's lying; that limits his scope. But a
successful shaman believes what he says -- and belief is contagious;
there is no limit to >his< scope. -- Jubal Harshaw, M.D, J.D.
Donald Qualls, aka The Silent Observer NAR # 70141-SR Insured
sil...@ix.netcom.com http://members.aol.com/silntobsvr/home.htm
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Opinions expressed are my own -- take them for what they're worth
and don't expect them to be perfect.
The Silent Observer
Jerry Irvine wrote:
>
> In article <8630196...@dejanews.com>, wo...@eda.mke.ab.com wrote:
>
> > Schecter has built his with a 38mm mount and plans to fly it with the
> > AeroTech 38/240 casing with an H123 or H242. Someone else was talking
> > about using the 38/360 case and flying it with an I161 but there was
> > concern over the motor length and space for the chute.
>
> I suppose you could go I65 54mm and out the chute on the side :)
>
> Converting it to 24mm D/E/F/G power is practical and even when stock (fins
> covered with tissue) sufficiently strong for:
>
> Estes: D12-7
> USR: D12-8 D24-8 E12-8 E25-8 E50-8 F25-8 F50-12 F100-12 G35-8 G70-12 G140-12
>
Those delays are a little long for a Fat Boy, Jerry. Even at optimum
weight (for a D12, about 6.5 ounces), the D12-3 delay is only about .5
second short, and the -4 is just right for an E18 reload. I doubt even
the F25 would need a full -8, though I gather your delays would give a
choice of -4 or -8 on that motor...and the -4 would almost certainly be a
good bit short.
Jerry Irvine
In article <3370D0...@ix.netcom.com>, The Silent Observer
<sil...@ix.netcom.com> wrote:
> Jerry Irvine wrote:
> > Estes: D12-7
> Those delays are a little long for a Fat Boy, Jerry. Even at optimum
> weight (for a D12, about 6.5 ounces)
You mean you don't piston launch your Fat Boy from a tower?
Jerry
Doyle Tatum
Kevin Boorn wrote:
>
> Has anyone uprated a Fat Boy to take D or larger motors?
Flys great on an 18mm Aerotech D21-4 - No modifications,
to speak of, necessary.
--
Doyle Tatum, RCDD
NAR #70025 doy...@mindspring.com
Member #554 NASA http://www.mindspring.com/~doylex
RMR FAQ = http://dtm-corp.com/~sven/rockets/rmrfaq.toc.html
The Silent Observer
Jerry Irvine wrote:
>
> In article <3370D0...@ix.netcom.com>, The Silent Observer
> <sil...@ix.netcom.com> wrote:
>
> > Jerry Irvine wrote:
> > > Estes: D12-7
>
> > Those delays are a little long for a Fat Boy, Jerry. Even at optimum
> > weight (for a D12, about 6.5 ounces)
>
> You mean you don't piston launch your Fat Boy from a tower?
>
I don't expect to, though I may use flash-pan to get all five motors
lit, if I every fly it with all five tubes loaded...
Mhollihan
One of our (Mid-South Rocket Society) club members converted his Fat Boy
to fly on D/Es with no problem. Be sure to use epoxy and careful
construction. Also, check to see that your kit didn't come with
lower-grade balsa fins (as mine did!) or you will be in for problems!
Finally, double-check your CG/CP balance with a string test, to be sure.
Mike Hollihan
Mid-South Rocket Society
NAR #53545
TRA #4309