L3 Certification Build: 8" Upscale Frenzy

jd2cylman said:

So,
I got a 8" x 10' 6" rocket that's still nekid after 2 flights... What would it take to bribe you to paint it?
No, never mind... With a paint job that beautiful, I'd be too afraid to take it out of the house.
Seriously, that looks friggen awesome! Well done.

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Considering it takes Nathan months to finish a paint job, you'd have to cash in your retirement. :wink:

Looking forward to your flight, Nathan (if it's on a Saturday). Looks incredible.

Stunning.... LOVE IT!

WOW! Nathan, that's simply beautiful!

Nick@JET said:

. . . I don't see any burn marks that you polished a little too much like the edge of fins or screw holes. . .

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I've accidentally sanded fin edges down to the bare fiberglass enough times in the past to hopefully have learned from my mistakes by this point!

When that happens you can do a pretty good touch up with a small brush. When using a brush, don't thin the paint as you would when spraying.

Beautiful work. I don't think I would want my rocket to look this nice, else I'd be afraid to fly it!

I have a couple questions, as I'm nearing completion of a smaller 4" Frenzy XL..

What size, how many and where did you place your parachute compartment vent holes?

When you painted the rocket, did you then have any trouble with a small thickness of paint on the edges of the components that prevented the parts from seating and thus aligning the shear pin holes? How did you deal with this issue?

I'm about to start painting today, and am considering how I can eliminate or minimize this issue... and if it's unavoidable, what's the best way to remove the paint from the tube end edges to allow the parts to line up without damaging the paint. I'll be using rattle cans or Rustoelum 2X white primer and gloss paint.

kevinkal said:

...What size, how many and where did you place your parachute compartment vent holes?

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I have a single 1/8" vent hole in the middle of the payload section. There is a similar vent hole in the booster section. There has been some discussion as to if those holes are large enough but several very knowledgeable people have told me that it should be fine.

kevinkal said:

...When you painted the rocket, did you then have any trouble with a small thickness of paint on the edges of the components that prevented the parts from seating and thus aligning the shear pin holes?

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No I haven't had any problem like that. I'm trying to think of what you might be referring to and the only places that I can think of where it could be a problem would be paint on the the edges of the av-bay switch band or the bottom edge of the nose cone. I just looked at those areas and there is a little paint there but certainly not enough to affect shear pin alignment. If you are experiencing that problem then I would attempt to remove the paint by sanding the edges with a sanding block.

Lovely work. Can you paint my rockets for me?

Nathan said:

I have a single 1/8" vent hole in the middle of the payload section. There is a similar vent hole in the booster section. There has been some discussion as to if those holes are large enough but several very knowledgeable people have told me that it should be fine.

No I haven't had any problem like that. I'm trying to think of what you might be referring to and the only places that I can think of where it could be a problem would be paint on the the edges of the av-bay switch band or the bottom edge of the nose cone. I just looked at those areas and there is a little paint there but certainly not enough to affect shear pin alignment. If you are experiencing that problem then I would attempt to remove the paint by sanding the edges with a sanding block.

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Thanks for the reply.

I wound up drilling three 3/32" vent holes in my "little" 4" Fiberglass Frenzy XL. It's going to be fairly fast and high.. so I'm trying to be careful. I have been researching what others have done and how they've analyzed the problem. If all vent holes are open, the force acting to separate my rocket due to internal pressure should be around 20 lbs peak for a flight to 16K at up to Mach 1.35. I don't know how fast and high you'll be going with your 8" Frenzy.. but it's good that you have a vent and discussed it. I'm no expert on this matter, but I would think a larger or perhaps multiple 1/8" holes would be in order. That 8" diameter makes for a lot of volume! If you're interested, here's a link to an interesting write-up and analysis on this matter: https://home.earthlink.net/~david.schultz/rnd/pressurelag/parachute.html

Regarding paint impacting shear pin alignment.. after my last paint job on a DD rocket, my pins and screws would not align.. so I had to sand off paint where the tubes butt together.. and I was hoping to avoid that this go around. You are correct, the problems were the joints at the Av bay switch band and nose cone bottom edge to payload tube upper edge. Getting the paint off the Av Bay switch band was difficult... as the Av bay coupler doesn't leave much room for sanding the edges of the switch band.

I think my vent holes will be sufficient. My rocket will not be going nearly as fast or as high as yours. The cert flight on a CTI M1810 sims at 3886 ft and 339 mph.

The cert flight is tentatively scheduled for the weekend of 11/18 so I'll let you know.

The pictures of Nathan's rocket don't do it justice. Saw it in person this past weekend, it's a work of art. Good luck with the flight.


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Nathan said:

I think my vent holes will be sufficient. My rocket will not be going nearly as fast or as high as yours. The cert flight on a CTI M1810 sims at 3886 ft and 339 mph.

The cert flight is tentatively scheduled for the weekend of 11/18 so I'll let you know.

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I had run some numbers for your 8" Frenzy compartments assuming no vent hole and no leakage (conservative) and with your three 4-40's, I agree with you.. you're fine for a 4k flight. For the 7K flight on the possible M2245, the numbers look more interesting. I was feeling guilty bringing this issue up.. as it was really a current personal interest item as I was working on my Frenzy's venting. I have it in my mind to run a parachute compartment pressure simulation for you when I have more time next week. I'm in a time crunch this week as I'm making final preparations for a cert flight on Saturday with either an M1297W or M1500G.

I was painting my Frenzy last night.. and all I could think about was how it did not compare to your finish! I've got a number of runs to sand out.. I was painting at 10pm.. 58 deg F but only 6% humidity here in CA, with terrible lighting (a work light dragged out of the garaged to the side yard). It was good equation for runny paint.

I look forward to your cert flight report!

Amazing like usual!

Going to bring it to BattlePark this weekend? Maybe do a shake down flight on an L, just to give it some "character"?

Hope to see you out there.

I'll fly it at BattlePark once some time this season. The first flight will be the cert flight with a CTI M1810 tenatively scheduled November 18th or 19th at Higgs farm with MDRA.

Reconfigured my altimeters today in preparation for my L3 cert flight next month.

Primary: RRC3
Drogue at apogee
Main at 600 ft

Backup: RRC2+
Drogue at apogee +1 second
Main at 500 ft

Deployment charges will be as follows:
Apogee: Primary 4.5g, Backup 5.5g
Main: Primary 5.5g, Backup 6.5g

Drogue chute will be a 36" FruityChutes elliptical
Main chute will be a 120" FruityChutes Iris Ultra

Nathan, overall looks good. One thing I would like you to consider is this- pop your main at a bit higher altitude. Bigger rockets require bigger parachutes. Usually bigger parachute require a bit more time to open. Maybe bump to 1000’ and 800’. My thinking anyway.


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I have used this 120" chute with my Formula 150 four times, deploying at 500 ft with no problems. For this rocket I will be deploying it at 600 ft. This has been approved by my L3 advisor.

Nathan said:

I have used this 120" chute with my Formula 150 four times, deploying at 500 ft with no problems. For this rocket I will be deploying it at 600 ft. This has been approved by my L3 advisor.

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I used an Ultra Iris 84" on my L3 flight. On shakedown flight I had main set at 900', ended up lowering it to 600' for my cert flight. That chute opens up really quick!

I agree with Mark 800' would be what I would do. Its a cert flight you want to make sure all works out well.

I think it depends on many factors, including the use of a drogue, d-bag, pilot chute, etc.

I use a pilot chute to pull the d-bag out of the payload and then pull the shrouds out of the elastic strap on the d-bag and then the bag off the main chute. Between the drogue chute and the time the pilot takes to pull eveything out, the rocket is pretty much stretched out below the main which is now in a vertical position and opens very quickly. I lowered the deployment from 1000 to 700 and could probably go to 500.

On the other hand I watch a L3 come in drogueless with the payload down. It deployed at 1000 ft. almost tangled the main in the cords as things fell and when the main finally opened and everything fell and jerked the recovery straight, the fin can was only about 100 ft above the ground.

Both methods work, but how high you deploy depends on HOW you deploy also, not just how fast the chute can open.

You're obviously going from experience on your deployment altitudes. I don't know your launch site, but understand there are plenty of tall trees in VA, so perhaps that's motivation to deploy a bit later. If it were me, I'd opt higher. I've seen a few fouled main parachutes correct themselves after falling (fast) a few hundred feet, the extra deployment altitude saved the day.
What do you anticipate the descent rate to be under the 36" Elliptical?
If you stretched out all your recovery components, how long would it be from the top of the 120" Iris to the bottom of your booster?

Nathan said:

I have used this 120" chute with my Formula 150 four times, deploying at 500 ft with no problems. For this rocket I will be deploying it at 600 ft. This has been approved by my L3 advisor.

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Nathan, fair enough. If you have it all worked out great. Good luck with the flight.


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I used to use apogee +1, now I use +2. Although altimeters may be close, I know from reviewing my post flight data that they are never exact. I changed this after I had a main deploy at apogee due to on over energetic charge. The extra second provides a bit more margin where I feel that the risk/reward is worth it.

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mpitfield said:

I used to use apogee +1, now I use +2. Although altimeters may be close, I know from reviewing my post flight data that they are never exact. I changed this after I had a main deploy at apogee due to on over energetic charge. The extra second provides a bit more margin where I feel that the risk/reward is worth it.

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I too have gone to the +2 seconds on redundant apogee charge.


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Successful L3 certification at MDRA today!!!!! It was a perfect flight to 3,926 ft on a rare calm day at Higgs Farm. And the best part is that the rocket didn't get a scratch on it.

I would like to thank Glenn, Dennis, Tom, Jess, Dave, and MDRA for all their help today. And also the following vendors who helped make this project a success:
AMWPro-X
Performance Hobbies
Upscale CNC
OneBadHawk
Missileworks
FruityChutes

Video coming soon . . .

Congratulations Nathan, Woohoo!

Congratulations Nathan! Well done

Woo! Congratulations! Can't wait to see the video.

Great flight Nathan!

Congrats! Rocket looks impressive on the pad!

From the Ether...

Great Job Nathan ! Glad to hear no scratches to buff out, congrats on your Level 3


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