LOC/Percision Forte fin Question...

LOC/Percision Forte fin Question...

Post by Jeff Lon » Thu, 31 May 2001 13:23:17



Just a general question for all those that have built one of these.  I am to
the point in construction where I have to decide whether or not I
want/should use fiberglass cloth to reinforce the external fin joints.  I
know that it is a no-brainer when it comes to the internal fin joints, but I
am worried about appearance.  I have never worked with glass prior to this
project and I want it to turn out right.  This is also my largest rocket to
date.  My smaller 2.6" dia rockets utilized fins that attached to the motor
mount which gave you 6 fillet points per fin, so glass wasn't needed (in my
opinion).  Being that the Forte fins only protrude through the wall about
1/16", I am worried about strength.

Thanks for your time

Jeff

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LOC/Percision Forte fin Question...

Post by William Frazie » Thu, 31 May 2001 20:32:46


 Being that the Forte fins only protrude through the wall about

Quote:
>1/16", I am worried about strength.

>Jeff

I recently built one of these and only used epoxy fillets on the fins with
30 min epoxy (I did 'paint' each entire fin with 30 min epoxy too).
Unfortunately my first flight resulted in a lawn dart, high winds and a G33
(I don't recommend using a G33 in the Forte). The forward part of the BT got
crumbled,  and a fin got buried in the ground up to the body tube.  I
checked the fin that got planted and it sustained no damage at all (except
for loss of paint).

William Frazier
NHRC
NAR # 79307

 
 
 

LOC/Percision Forte fin Question...

Post by BRMut » Thu, 31 May 2001 19:49:22


Hi Jeff!
  An easier way to go may be to make your own fin copies with some aircraft
plywood.  Make a longer tab, so it will go to the motor mount.  I did this with
mine and used wood glue for the construction.  It's really strong, and other
than a zipper on the first flight, hasn't been any problem at all.  Wonderful
flier on a G64-7 or an H180-M

Fly straight and true!

MikeyR

 
 
 

LOC/Percision Forte fin Question...

Post by Joe Cacciato » Thu, 31 May 2001 22:46:47


I built mine to stock and have flown it once with no problems.

I am converting mine to a camera rocket and was wondering if anyone
had the RockSim file for the Forte. I want to know what all the added
weight in the payload section will do with the Forte.

You said the G33 was not a good engine for the Forte. Why? Mine is
going to be so heavy it is going to need something like a G33 or G64.

Joe C.
www.joecool.org/myrockets.htm
NAR 79136

On Wed, 30 May 2001 04:32:46 -0700, "William Frazier"

Quote:


> Being that the Forte fins only protrude through the wall about
>>1/16", I am worried about strength.

>>Jeff

>I recently built one of these and only used epoxy fillets on the fins with
>30 min epoxy (I did 'paint' each entire fin with 30 min epoxy too).
>Unfortunately my first flight resulted in a lawn dart, high winds and a G33
>(I don't recommend using a G33 in the Forte). The forward part of the BT got
>crumbled,  and a fin got buried in the ground up to the body tube.  I
>checked the fin that got planted and it sustained no damage at all (except
>for loss of paint).

>William Frazier
>NHRC
>NAR # 79307

 
 
 

LOC/Percision Forte fin Question...

Post by RDH8 » Thu, 31 May 2001 23:24:17


I have built two.
The first one I build per the instruction.
The fin filets cracked on landing.
Part of the reason was that I didn't use fibers in the fillet.
The second one I modified it to separate just above the fins.
I cut the BT ~3in above the fins and installed a coupler there.
I then screwed the NC on so it wouldn't come off.
I had to make a blocker so the chute wouldn't get pushed up to the NC. Some
people would just mount a bulkhead in the BT for this but I just attached a
CR to a ~18in section of MMT and slipped this into the BT so one end of this
MMT was up against the NC.
I rigged the shock cord so the chute was closer to the fin can so that they
wouldn't hit each other and so that the NC hits the ground first.

With this setup I have had no problems with damaged fins.
But you have to be careful of how you pack the chute.
The 'blocker' needs to take up any extra space in the BT.
I only had one event where the chute didn't come out.
But because the BT separates in the back it came down flat and there was no
damage.

Good luck
RDH8


Quote:
> Just a general question for all those that have built one of these.  I am
to
> the point in construction where I have to decide whether or not I
> want/should use fiberglass cloth to reinforce the external fin joints.  I
> know that it is a no-brainer when it comes to the internal fin joints, but
I
> am worried about appearance.  I have never worked with glass prior to this
> project and I want it to turn out right.  This is also my largest rocket
to
> date.  My smaller 2.6" dia rockets utilized fins that attached to the
motor
> mount which gave you 6 fillet points per fin, so glass wasn't needed (in
my
> opinion).  Being that the Forte fins only protrude through the wall about
> 1/16", I am worried about strength.

> Thanks for your time

> Jeff

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LOC/Percision Forte fin Question...

Post by David Weinshenke » Fri, 01 Jun 2001 03:13:36


Quote:

> I am almost afraid to ask this but I thought the G80 was also
> considered a HPR motor??

It's actually the largest available motor that is considered
to be a "model rocket" motor instead of a "high power" motor,
according to the criteria presently specified by NAR/NFPA-1122.

-dave w

 
 
 

LOC/Percision Forte fin Question...

Post by Joe Cacciato » Fri, 01 Jun 2001 03:24:34


Yep, I went on the AT web site and saw the specs for G80, G64 and G33
and how the impulse and propellent weight differ to give you the
different ratings. For sure the G33 is a low thrust, long duration
engine.

What I still don't like about the AT site is I can't quickly find the
maximum recommended lift-off weight for each engine. The engine matrix
sheet which I have home list it but I can't find it on the ATsite
under the engine spec section.

Joe C.

On Wed, 30 May 2001 11:13:36 -0700, David Weinshenker

Quote:


>> I am almost afraid to ask this but I thought the G80 was also
>> considered a HPR motor??

>It's actually the largest available motor that is considered
>to be a "model rocket" motor instead of a "high power" motor,
>according to the criteria presently specified by NAR/NFPA-1122.

>-dave w

 
 
 

LOC/Percision Forte fin Question...

Post by Alex Merica » Fri, 01 Jun 2001 03:27:29


Both G64 and G80 are wonderful motors for this rocket.

Quote:

> I'd go with a G64 or G80 for this rocket.

--
Alex Mericas
NAR 62956 Level 2
Senior Advisor, Austin Area Rocketry Group
 
 
 

LOC/Percision Forte fin Question...

Post by Lance Licktei » Fri, 01 Jun 2001 04:53:28


Man, I'm feeling particularly dense today, but I don't have a clue what
good the explained blocker does for you.  Don't all the forces on the
rocket push the innards *aft* and not toward the NC, making this a
non-issue?

Thanks,  --Lance.

Quote:

> I have built two.
> The first one I build per the instruction.
> The fin filets cracked on landing.
> Part of the reason was that I didn't use fibers in the fillet.
> The second one I modified it to separate just above the fins.
> I cut the BT ~3in above the fins and installed a coupler there.
> I then screwed the NC on so it wouldn't come off.
> I had to make a blocker so the chute wouldn't get pushed up to the NC. Some
> people would just mount a bulkhead in the BT for this but I just attached a
> CR to a ~18in section of MMT and slipped this into the BT so one end of this
> MMT was up against the NC.
> I rigged the shock cord so the chute was closer to the fin can so that they
> wouldn't hit each other and so that the NC hits the ground first.

> With this setup I have had no problems with damaged fins.
> But you have to be careful of how you pack the chute.
> The 'blocker' needs to take up any extra space in the BT.
> I only had one event where the chute didn't come out.
> But because the BT separates in the back it came down flat and there was no
> damage.

> Good luck
> RDH8



> > Just a general question for all those that have built one of these.  I am
> to
> > the point in construction where I have to decide whether or not I
> > want/should use fiberglass cloth to reinforce the external fin joints.  I
> > know that it is a no-brainer when it comes to the internal fin joints, but
> I
> > am worried about appearance.  I have never worked with glass prior to this
> > project and I want it to turn out right.  This is also my largest rocket
> to
> > date.  My smaller 2.6" dia rockets utilized fins that attached to the
> motor
> > mount which gave you 6 fillet points per fin, so glass wasn't needed (in
> my
> > opinion).  Being that the Forte fins only protrude through the wall about
> > 1/16", I am worried about strength.

> > Thanks for your time

> > Jeff

> > -----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
> > http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
> > -----==  Over 80,000 Newsgroups - 16 Different Servers! =-----