[NRV Rocketry] Suggestions for good L2/L3 Rockets?
Thomas Weeks
tweeksjunk2 at theweeks.org
Tue Jul 15 23:03:48 CDT 2014
Sure Sandra.. I'll take care of that. One note first though (to all folks on
list) -- We have another "nrvr-launches" list that is designed to be low-
chatter, launch announcements only. It is here:
http://nrvr.org/mailman/listinfo/nrvr-launches
If you only want to hear about launches, you might want to join that list.
That being said, all folks on both this list and the launches list have full
control over your status on the list. That's why you get a monthly email
telling you your account management password. Just look for the emails with
"memberships reminder" in the title, and it includes a link to your list
settings login from where you can un-subscribe, stay on but just get singe
email digests of the occasional chatter. :)
Hope that helps,
Tweeks
On Monday 14 July 2014 22:15:54 Arthur. Sandra wrote:
> Can I please be removed from this e-mail list? Thanks, Sandra Arthur
>
> ----- Original Message -----
>
> From: "bruce fette" <brucefette at yahoo.com>
> To: "nrv rocketry" <nrvr at nrvr.org>
> Sent: Saturday, July 12, 2014 12:51:53 PM
> Subject: Re: [NRV Rocketry] Suggestions for good L2/L3 Rockets?
>
>
>
> Tweeks,
>
>
> As I did my L3, I was guided over and over to make it really strong, and
> really simple! Everything must be redundant and everything must work
> exactly as planned! Yes Tripoli rules are slightly different from NAR
> rules, so read up!
>
>
> So let me tell you what I did to make everything simple. for example 3FNC
>
>
> 1) I used LOC tubes, but if you can find a good nose cone to match the ID
> of a "concrete sonotube", then you can simply fiberglass the sonotube and
> have a really strong design. My most recent visits to Home Depot and Loews
> I didnt find any decent sonotubes. They were all warped out of round and
> beat up. It may be better in Blacksburg. I used two pieces of Loc
> precision 5.5" tubing, for which it is easy to find a matching Loc nose
> cone. I bought a rotisserie and made cardboard inserts to the tubing
> diameter so that I could use that to rotate the tubing while glassing and
> painting.
>
>
> 2) Since the LOC tubes are not particularly thick, I lined them full length
> with another piece of loc tubing cut down to coupler thickness.
>
>
> 3) I made a 6 tube fin design where the tube fins were bolted to the frame
> with 8/32 TNUTS and bolts = 6TNC. When it lands, if you break a plywood
> fin, you have to do it all again. If you only bend a tube fin, you can
> straighten out the bend and you are ready to fly again. (Its all about the
> rules). If you choose to do plywood fins, be sure to use 1/2" birch
> plywood.
>
>
> 4) Dual deploy is a must so that you land at or below the 15 f/s landing
> velocity. Use two different types of altimeters so there can be no common
> design fault (have one use beeps and the other use LED flashing so you
> don't get confused about the eventual altitude). Use a big chute for the
> main and pop at 500-600 ft so it has enough time to open. And good strong
> risers, and good strong welded eyebolts. 1/2" plywood and good big fender
> washers. 1" risers at least 20 feet long and sewn really well by a shoe
> maker.
>
>
> 5) Motor mount was redundant, both at the nozzle and up at the forward
> closure.
>
>
> 6) You must be able to shut off the redundant electronics without moving
> the rocket, and you must be able to validate that each squib has fired
> without any danger to the reviewer. So you need to be able to ascertain
> the charges shot without moving the rocket in any way.
>
>
> 7) With care you can also make the motor igniter redundant.
>
>
> 8) So my L3 was a single purpose built. But I have recently determined that
> there is a high value in supporting a rather larger diameter motor, and
> doing your construction so that you can insert various motor adapters and
> thereby adapt the motor mount to smaller diameters. I do that by inserting
> a plywood centering ring to adapt the diameter, a smaller motor tube and a
> plywood thrust plate that can bolt to the original thrust plate. So I can
> adapt to various motor plans including clusters with various arrangements.
>
>
> 9) Sure bigger diameter, more drag, lower altitude. The alternative is to
> do your L3 elsewhere (Arizona, Colorado, Las Vegas, Blackrock etc =
> ROADTRIP :)))!)
>
>
> Good Luck,
> Bruce
>
>
>
>
>
>
>
>
>
>
>
>
>
> From: james desposito <jdesposito69 at hotmail.com>
> To: nrv rocketry <nrvr at nrvr.org>
> Sent: Saturday, July 12, 2014 1:55 PM
> Subject: Re: [NRV Rocketry] Suggestions for good L2/L3 Rockets?
>
>
>
>
>
> NO it can be a kit
>
>
>
>
> From: maier.chris at gmail.com
> Date: Sat, 12 Jul 2014 08:58:07 -0500
> To: nrvr at nrvr.org
> CC: tweeksjunk2 at theweeks.org; nrvr at nrvr.org
> Subject: Re: [NRV Rocketry] Suggestions for good L2/L3 Rockets?
>
>
> Go motor mount-less. Fixing a motor mount tube in large airframes proves
> inflexible if you happen to attend an LDRS or big waiver type of launch.
> You end up having to build another purpose but rocket instead of just
> swapping in a 98mm motor.
>
>
> I would recommend against any cluster that lacks a central motor capable of
> lifting the rocket solo for a cert flight - too much could go wrong for a
> cert flight, and the highest priority is safety when launching the larger
> L3 type rockets as well. Air start your clusters to minimize issues and
> provide better distance between the rocket and spectators in case there is
> an issue like one of the motors doesn't light or come up to pressure at
> the same time as the others.
>
>
> Don't the rules still specify an L3 project has to be scratch built?
>
>
> Chris
>
> On Jul 12, 2014, at 7:23, james desposito < jdesposito69 at hotmail.com >
> wrote:
>
>
>
>
>
> After a lot of homework and building a 5'' Big Nuke kit from Loc for my
> level 3 i found out it is going to hit a altitude of over 10,200 feet and
> not to many places to fly. know I''m thinking more toured a 7.67'' rocket
> like the Bruiser-EXP - 3" from Loc that will stay under 10,000 feet
> with the smallest M. You have a better chance of keeping your rocket with
> an 8'' just my opinion. jimmy d
>
> > From: tweeksjunk2 at theweeks.org
> > To: nrvr at nrvr.org
> > Date: Sat, 12 Jul 2014 02:00:08 -0400
> > Subject: [NRV Rocketry] Suggestions for good L2/L3 Rockets?
> >
> > Hey all..
> >
> > So we've had a lot of people certing up as of late. They've got their
> > Level-1 (H-I motors) and Level-2 certs (J-L).. and some are trying (or at
> > least starting to think about) their Level-3 now (M-O motors).
> >
> > I'm thinking my next big rocket will probably be a 5" (dia) airframe,
> > probably all fiberglass or bluetube. Maybe scratch built (with a nice big
> > ebay for lots of electronics and HAM radio gear).. maybe a kit. I like
> > the flexibility of a multi-motor cluster, like what Giovanni had on his
> > black momba:
> > http://nrvr.org/photos/2012-02-04-5_NRVR-VAST-VT-Launch/IMG_2421.JPG
> > http://nrvr.org/photos/2012-02-04-5_NRVR-VAST-VT-Launch/IMG_2422.JPG
> > http://nrvr.org/photos/2012-02-04-5_NRVR-VAST-VT-Launch/video/MVI_2435.fl
> >v.html
> >
> > or maybe a just a more traditional single 75mm:
> > http://nrvr.org/photos/2011-09-10-11_NRVR-VAST-Launch-WEB/2011-09-10-11_n
> >rvr- vast-launch/img_1053.jpeg.html
> >
> > Suggestions.. thoughts.. related questions?
> >
> > Tweeks
> > p.s. we're working out the final details for another Kentland launch in
> > two weeks (26th).
> > _______________________________________________
> > NRVR mailing list
> > NRVR at nrvr.org
> > http://nrvr.org/mailman/listinfo/nrvr
>
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>
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