[roc-chat] Re: G10 fin thickness question?
- From: SpartaChris <spartachris@xxxxxxxxx>
- To: roc-chat@xxxxxxxxxxxxx
- Date: Thu, 26 Apr 2012 15:44:05 -0700
Fin flutter largely depends on the shape of the fin as well as the
thickness. Hit up Giant leap's fin flutter calculator to get an idea of the
velocity your fins will begin to flutter at. This should give you a decent
starting point when planning what size motors to go with.
Don't forget, there are also 75mm K motors, and you can easily adapt down.
Adapting up, however, is a bit more challenging.
On Wed, Apr 25, 2012 at 7:45 PM, Kenneth Brown <ken@xxxxxxxxxxxxx> wrote:
> It's more a question of what velocity you are expecting. 1/8" G10 fins on
> a 4" Goblin with a K1100 (54mm) isn't going to fare very well. Mine didn't
> and it had the stock birch ply fins.
>
> If you plan to fly slow, use the 1/8". I would go with the 3/16" myself.
> You can always find a use for the 1/8" stock later.
>
> Ken (AKA, AG6LD) Brown
> Got my call sign. Amateur Extra on my first try.
>
>
> On Apr 25, 2012, at 5:48 PM, John Howard wrote:
>
> > I’m building a scratch dual deploy 4” G10 3FNC rocket, and was planning
> on using 54mm motors. If I used a 75mm MM then I could launch my first L
> motor up at XPRS in September (and 54mm’s with an adapter). I will be doing
> slots through the airframe with reinforced filets inside and out and I
> already have 1/8” G10. Most kits online look like they use 1/8” G10 for
> 54mm kits, and 3/16” G10 for 75mm/98mm kits.
> >
> > Am I asking for trouble if I use 1/8” G10 fins with a 75mm motor like a
> Ceseroni L800 or Aerotech L850W? In ROCSIM both look like rocket would be
> above 1100 ft/sec for about 2.5 seconds ? Or should I just stick with the
> 54mm??
> >
> > Any input would be appreciated!!
> >
> > Thanks,
> > John
> >
> > Sent from my old iPhone
> > --
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> >
>
>
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--
-Chris
TRA # 10762 L3
12" Talon on a P build:
ROL:
http://www.rocketryonline.com/modules.php?name=Forums&file=viewtopic&t=950
TRF: http://www.rocketryforum.com/showthread.php?t=3797
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