NEW 8" GIZMO XL FROM PERFORMANCE ROCKETRY

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Not sure if you would know this but can PR do white colored fiberglass tubes. It would be a very nice color for some scale kits.
GP


Hey Gary.....
I had a white NC, spiral wound.
So I would imagine they do white tubes.

100_8938.jpg
 
Jim
Hope you had a nice Turkey Day. I just thought it would be nice for Tim or PR to have white tubes. The Nike Smoke line with tube and nose cone already colored. Us guys up here in the frozen tundra could build and not have to wait untill warm weather comes in May to paint.
See Ya
GP
 
Still in a holding pattern for Peter A to finish editing Sundays flight videos. Only went 3553 on the two grain AMW L-700. Because of the unintended drag race on Saturday---no video of the AMW L-1750 flight, only went 4632". Both flights did recover as advertised using the Rat-Works ARRD for free-bagged main deployment.

https://www.mdra-archive.org/photos.../Full/November_2011_Fred_Wallace_Gizmo_XL.wmv

Hi Fred, and Gary. I have a Gizmo XL on order and have been watching your build threads and launch videos with enthusiasm. You both do nice work and I've picked up some good ideas from you. I notice the altitudes you guys are getting seem to be much lower in altitude than expected. Using Rocksim 9 with a 20 lb finished rocket I am getting significantly higher simulated altitudes. Going up to 23 lbs (Gary's dry weight) still gives optimistic altitudes in Rocksim. Does the Cd in rocksim need to be adjusted because of some quirk in the design? I have Rocksim set to auto calculte Cd at simulation time
 
I only use Rocksims calculated Cd as a starting point, Once the rocket is flown I'll then adjust the Cd till the sim gives me what I actually got for altitude in the flight, The more the rocket is flown the more you can tweak the Cd getting closer and closer to your sim each time.

My Cd is set to .37 try that.
 
I only use Rocksims calculated Cd as a starting point, Once the rocket is flown I'll then adjust the Cd till the sim gives me what I actually got for altitude in the flight, The more the rocket is flown the more you can tweak the Cd getting closer and closer to your sim each time.

My Cd is set to .37 try that.

Thanks Gary. With the Cd set at .37 for a 21.4 lb build I get within a few feet of the actuals. You said your rocket was 23 lbs. dry. How did you get it so heavy? What nose weight did you finally use? I Rocksimed your construction technique (4" tube in nose etc.) and I come up pounds lighter. Is it possible that paint and epoxy are worth 2 or 3 pounds? Maybe so. One thing I wanted to do with my X-celerator was to weigh it before and after painting and I forgot.
 
Again, I never use any of the weights in Rocksim as it doesn't have any of the correct Performance Rocketry weights.

I build the rocket weigh it then add that total weight into my sim, That weight also includes my:

Chute - Star Chute Large
Shock Cords - Tubular Kevlar X2
1/4" Quick links
Aeropack
U-Bolts Etc etc
Plus I tend to build Strong!

I also don't add any Mass objects into the file, Again I just weigh the rocket ready to fly (No Motor) At that point balance the bird on a string get your CG and add that to the sim as well. Now your ready to sim specific motors and get the correct CP-CG ratio.
 
Thanks for the info Gary. Of late, I actually weigh every part that goes into a build and set the weight and C/G manually. I get a pretty accurate result and only the paint and epoxy change the final figures. I have made some measurements on alot of Performance Rocketry parts and put them into my database. I corrected a couple of Rocksim files for Wildman last year as the C/Gs were so far off the actual kits.

I think you have a fan here. I have 3 of your designs now; X-celerator, Gizmo XL and HellFire 4 (or will have when UPS arrives next week). Can't wait to start on the Gizmo XL.
 
Thanks Dave and glad you like the kits, The GIZMO XL isn't mine though thats a PR design. Its a really fun kit though.
 
Gary-

Did you drill a vent hole in any part of the 4in tube in the nose cone for the main chute, or is a vent hole not needed? Never did a set up like this before and want to be sure before I glue everything up.

Preston
 
Gary-

Did you drill a vent hole in any part of the 4in tube in the nose cone for the main chute, or is a vent hole not needed? Never did a set up like this before and want to be sure before I glue everything up.

Preston

Preston:
No vent holes in the 4" tube that holds the main?

Here is what I do, For the Main I use a piston in the 4" BT that holds the Main.

  • The piston gets attached to the main chutes D-Ring loop at the top of the chute via the quick link in the pic.
  • On the underside of the piston is a small Blastcap
  • An Ematch goes in the Blastcap with your BP & Dog barf and is then taped closed.
  • The Ematch lead comes up through that small hole next to the Eyebolt and is connected to the terminal block on the top of the Av-Bay.
  • Once the charge goes off the piston pushes the chute out breaks the small ematch lead and the piston remains connected to the chute.
0073.jpg

0102-1.jpg

0092-1.jpg
 
Preston:
No vent holes in the 4" tube that holds the main?

Here is what I do, For the Main I use a piston in the 4" BT that holds the Main.

  • The piston gets attached to the main chutes D-Ring loop at the top of the chute via the quick link in the pic.
  • On the underside of the piston is a small Blastcap
  • An Ematch goes in the Blastcap with your BP & Dog barf and is then taped closed.
  • The Ematch lead comes up through that small hole next to the Eyebolt and is connected to the terminal block on the top of the Av-Bay.
  • Once the charge goes off the piston pushes the chute out breaks the small ematch lead and the piston remains connected to the chute.
0073.jpg

0102-1.jpg

0092-1.jpg

Those pics cleared up a few questions I had. Thanks Gary for some great ideas. Cant wait to get started on mine. I have visions of the M2250 in this thing.
 
Gary, I didn't realize that you used a piston in the Gizmo XL. From your previous posts I got the impression that you laid a BP charge in front of the main and covered the opening of the 4" nosecone tube with tape to seal the chute in. Did you change your idea during the build or did I miss something? I was planning on putting a BP charge in a an enclosed centrifuge container in front of the main and use the tape method you described. I would think that the presure buildup would easily break the tape and force the main out before the pressure is dissipated.
 
Sorry Dave thought I replied.

Yes I flew the Gizmo XL with and without the Piston, Thing is the flight employing the piston one off the E-Match leads broke off of the terminal block, I should have taped the leads down to keep them tucked away, My guess is after falling from 6000' the drogues shock cord hit the mains leads.

Luckily the Gizmo XL sustained virtually ZERO damage, I mean not even a scratch lol

In the end after "ground testing" I prefer the piston for this set up, Without having the aid of the NC to pull the chute out I feel the piston is a bit more reliable.
 
Those pics cleared up a few questions I had. Thanks Gary for some great ideas. Cant wait to get started on mine. I have visions of the M2250 in this thing.

Jason,

Jenny's useing one of these for her Level 3 at Thunderstruck in the spring, she's thinking a M1770 6 grain skid if it fits. If not a 5 grain M1300 Dual Thrust. Shes going to use Gary's dual deploy design.
 
Jason,

Jenny's useing one of these for her Level 3 at Thunderstruck in the spring, she's thinking a M1770 6 grain skid if it fits. If not a 5 grain M1300 Dual Thrust. Shes going to use Gary's dual deploy design.

Very Cool! Be sure to post pics, The M1770 isn't going to leave much room at all for the main though, The 5G can probably be used but I think the M2250CS would be the best, But thats totally up to Jenny.

Looking forward to seeing it.
 
Gary,

That's what we're wondering if there is enough room for the 6 grain case. It's right at 36" long, so she will have to figure out which chute she's using after it's built. If she can keep it at around 20 to 23 pounds the Recon chute that is coming with it or a 60" Skyangle should be enough, I think that would fit with the 6 grain case. You can ask anyone that knows her, she's a Skidmark girl & the M1770 is the smallest 75mm "M" skid CTI has.

Here's a photo of her 5" Gizmo, she's doing the same thing but reversed, purple base paint & yellow stripes.

Tigress.JPG

Mike
 
Jason,

Jenny's useing one of these for her Level 3 at Thunderstruck in the spring, she's thinking a M1770 6 grain skid if it fits. If not a 5 grain M1300 Dual Thrust. Shes going to use Gary's dual deploy design.

I'd like to see the M1300. I'd LOVE to see the M2250! What about the M2020 IMAX? :eek:
 
Steve,

All nice choices, but If she can shoe horn the 6 grain into it, you know she prefers to lite that field on fire with skids. I think her second choice would be the Dual Thrust, she likes the way my M-Force flies on it.

Mike
 
Jason,

Jenny's useing one of these for her Level 3 at Thunderstruck in the spring, she's thinking a M1770 6 grain skid if it fits. If not a 5 grain M1300 Dual Thrust. Shes going to use Gary's dual deploy design.

Awesome, can't wait for that. I will be doing this same design. It looks pretty solid.
 
Steve,

All nice choices, but If she can shoe horn the 6 grain into it, you know she prefers to lite that field on fire with skids. I think her second choice would be the Dual Thrust, she likes the way my M-Force flies on it.

Mike

Gotta love her for that! Either way, I can't wait till Thunderstruck 2012!! Good luck Jenny!!
 
It's nice having my wife fly with my son & I. I don't have to lie about buying motors, just so long as she gets some. Plus she gets better deals with Tim than I do.

Mike
 
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Hi All
I have built many PR and Wildman kits and have had this problem before with nose cone not fitting body tube. My Gizmo XL came in today. The nose cone shoulder is not out of round. I have sanded a lot of the gel coat off already. It looks like I will need to sand off most of gel coat for it to work than reinforce inside of shoulder. Why does this happen.
Thanks
Gary
 
Hi All
I have built many PR and Wildman kits and have had this problem before with nose cone not fitting body tube. My Gizmo XL came in today. The nose cone shoulder is not out of round. I have sanded a lot of the gel coat off already. It looks like I will need to sand off most of gel coat for it to work than reinforce inside of shoulder. Why does this happen.
Thanks
Gary

I have the same issue,,

Tom
 
Hi All
I have built many PR and Wildman kits and have had this problem before with nose cone not fitting body tube. My Gizmo XL came in today. The nose cone shoulder is not out of round. I have sanded a lot of the gel coat off already. It looks like I will need to sand off most of gel coat for it to work than reinforce inside of shoulder. Why does this happen.
Thanks
Gary

Sad to say, but, sometimes Curtis or his hired help get in a rush to make the cones..Either the molds are not clamped down firmly enough or they take them out of the molds too early before the resin has fully cured..
 
I just picked up a new 8'' Gizmo also.....with my luck, he will come out with a new spiral wound version (right after I paint mine)

Either way.....better than a plastic cone ANY DAY.
 
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