L1 Cert choices

Advertise with us
eggtimer rocketry
SilicdyneTRF
Onebadhawk
The Rocketry Forum

Help Support The Rocketry Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
DavidMcCann said:
pull the tape too late, and you'll have ridges.
Click to expand...

Currently re-sanding a rocket for that reason. Because the entire forum was all you got gravel fillets. They structurally held, but man they looked worse than awful. Try to do the fillets right the first time like David explains because it takes longer to fix it.
 
I’ve found fixing my own mistakes, that wrapping a Spent D motor in sandpaper helps.
 
Well I've had rocketpoxy down for 30-50 minutes. Trying to do sixteen fillets at once. There's a lot of fillet area compared to a BH29. I just gotta pull the tape up before its like cured this time. Tacky is a word for it. The alcohol trick helped some more.
 
Found some good information on phenolic at San Diego Plastics.

Phenolic sheet is a hard, dense material made by applying heat and pressure to layers of paper or glass cloth impregnated with synthetic resin. These layers of laminations are usually of cellulose paper, cotton fabrics, synthetic yarn fabrics, glass fabrics or unwoven fabrics. When heat and pressure are applied to the layers, a chemical reaction (polymerization) transforms the layers into a high-pressure thermosetting industrial laminated plastic.

PAPER REINFORCED PHENOLIC - Normal electrical applications, moderate mechanical strength, continuous operating temperature of 250°F.

CANVAS REINFORCED PHENOLIC - Good mechanical and impact strength with contiunuous operating temperature of 250°F.
Click to expand...

John Coker reports that MAC rockets are made of canvas phenolic and PML tubes are paper phenolic. He also notes regarding canvas phenolic: "In terms of brittleness, it falls closer to the PML end of the spectrum." This explains finding both negative and positive reviews of phenolic; until MAC, canvas phenolic was not common.

Does anyone know how MAC rockets take primer and paint? They have no spiral groove to fill.
 
Hi Randy,
Great sailplane photos!
My first HP and L1 was a Loc Precision Vulcanite H76 (https://www.locprecision.com/product/vulcanite-h76/)2.26) 38mm MMT that I have flown on G's thru I's over 40 times, both single and dual deploy!
I highly recommend whatever rocket or rockets you build to include the AeroPac (https://www.aeropack.net/) motor retainers and adapters!
Makes things a lot easier in my opinion.
Lately, I just use single deploy and a Jolly Logic Chute Release (https://www.jollylogic.com/products/chuterelease/) as do at least a dozen others in our club.
Enjoy!

Take a look.
 
Nice to meet you, Ken. Thx for the kudos. R/C is a great hobby with the same inspiration as model rocketry.

My first HP and L1 was a Loc Precision Vulcanite H76 (https://www.locprecision.com/product...nite-h76/)2.26) 38mm MMT that I have flown on G's thru I's over 40 times, both single and dual deploy!
Click to expand...

I get it. There's been enough time for all the feedback here to sink in, and for me to research new things. One of them is just doing SD and getting the L1, then letting DD happen in its own time. And OMG I am actually considering a phenolic rocket. It was great to post here and learn.

I highly recommend whatever rocket or rockets you build to include the AeroPac
Click to expand...

Thanks... the Slimline had caught my eye, but I haven't compared them in detail. I'm also prone to scratchbuilding.

Lately, I just use single deploy and a Jolly Logic Chute Release
Click to expand...

Well, fact is I got a PM recommending the JLCR in the last couple days. So now I'll admit in public I'm into benchrest target shooting and handload every round. BP feels comfy and (pardon me) NASA-like. I read a few posts here about JLCR fails that dissuaded me, but now you are supporter #2 in 2 days. Thanks for your input, but this may be a whatever floats your boat decision. I like the Raven3 with four outputs and two accelerometers. Tech junkie, what can I say?


I saw you're from Tucson. My parents live in Queen Creek. About four months ago we visited the Titan missile complex to your west. It probably contributed to my interest in HPR.

It's a tour everyone into rockets should take. Awesome in many dimensions.



IMG_0084.jpg


IMG_0091.jpg


IMG_0097.jpg


IMG_0101.jpg


IMG_0112.jpg


IMG_0127.jpg


IMG_0082.jpg


IMG_0081.jpg
 
Andrew_ASC said:
Well I've had rocketpoxy down for 30-50 minutes. Trying to do sixteen fillets at once. There's a lot of fillet area compared to a BH29. I just gotta pull the tape up before its like cured this time. Tacky is a word for it. The alcohol trick helped some more.
Click to expand...

Andrew, that will cause chaos. Do two fillets at once. Let them set, and do the next set the next day. Takes longer but is a much better method.


Sent from my iPhone using Rocketry Forum
 
Rockethound said:
Does anyone know how MAC rockets take primer and paint? They have no spiral groove to fill.
Click to expand...

I tried a couple MAC kits last fall (a 54mm Black Fly and 54mm Scorpion XL), now I have 4 finished MAC rockets and 2 more under construction. Consider yourself warned. :) The Black Flies are really fun (watch your Cg/Cp, they need nose weight). The Scorpion XL is versatile, can do SD with just the booster + NC class 1 motor flights, DD on "big" class 1 motors (H242, H130, H148 etc), and of course DD and Mach+/mile+ on big nasty Js.

No spirals to fill, which is awesome. The linen fabric does have lot of little pin holes which I've had good luck filling with Bondo GSP and sanding off before painting. Tubes and fins are then easily primered and finished. Rough everything up with sandpaper.

It's a little annoying that the tube IDs are very round, and then the OD can be a little eccentric, I guess this is the nature of rolling/wrapping the linen fabric. Not a big deal, but pay attention to how the tubes line up, and sand to match if needed.

I really like MAC kits, the attention to detail and fitment of parts is superb. Mike is great to deal with as well. His kevlar harnesses are very nice. They build quickly and easily. And no, I don't have a stake in MAC!

I like that the phenolic is waterproof... I've tested that with a lake landing and the rocket floated long enough to retrieve it via boat (well over an hour). The foamed fin can and my sealed NC kept it afloat. Like a FG kit you can wash the rockets out when they get gross from BP residue.

IMO it's worth the extra $ to upgrade to the FWFG nose cones. You won't regret a JLCR and some kind of GPS tracker either.

Read MPitfield's Black Fly build thread in MPR if you haven't yet, lots of info there.
 
Last edited:
One benefit of a JLCR is t so much avoiding using BP, but being able to do DD out of a single break in the airframe. Allows you to cut a significant amount of weight out of the equation.

If you’re opening up to the idea of flying Gs single deploy (which I think will be much simpler and less stress), id recommend either a 2.6” or 3” airframe with a 38mm Mount. Fly it short on small motors, and stack on the DD gear for bigger flights.

3" Darkstar short on an H178DM, then full stack on a K1100T
10028628506_92122a7e8c.jpg
17084519040_8308c23b14.jpg


2.6" Screech on a J510W. Could be flown short... Haven't done it on anything but 1200 and 1320's yet. (bought the rocket to have something to fly G80's on..lol)
17722782578_00f97c8dcc_z.jpg
 
Last edited:
One benefit of a JLCR is not so much avoiding using BP, but being able to do DD out of a single break in the airframe.
Click to expand...

I see. Maybe the failure rate of JLCR is similar to BP DD but got more-negative "press" due to its newness. I understand its concept, but found stories of chutes not opening. I also read it needs a certain diameter tube, but I've forgotten the value at the moment.

The Darkstar is fabulous. I love its lines. Is that Wildman's 3" DS? I found a 3" Darkstar DD Rocksim file, pulled out all the DD hardware and payload bay, saved it as 3" Darkstar SD. But doggone it, the weight is shown as 2370g no motor. Here is the ORK file:

View attachment Wildman Dark Star 3 inch SD.ork

Does that weight make sense?
 
Is mass override on? That would set a static weight no matter what you edit. Mine is 11 pounds on the pad with a 54/1706 loaded up. (K1100 or K805 in my case). I’ll toss the booster on the scale tonight.


I would put the JLCR failure rates as lack of experience. It’s a new item so there was no knowledge base to turn to. As more people fly them and talk to each other, I’ve seen the rates of failure generally decreasing.
 
Last edited:
Only a couple masses have overrides in the file I posted. They are very close to calculated and appear to be actual weights.

There are Darkstar Jr ORK files for DD and short configuration in this thread. A shortened DS Jr will do the job, and the DD version will almost stay under 1500g.

I've been reading about the JLCR. JL says "May work in some 38mm rockets" so I suppose a 54mm is the smallest reliable tube. Maybe it's just what I've read, but it seems Group A is "DD mostly" and Group B is "JLCR mostly". I'll keep reading.

This has been a good thread. People have opened my eyes to new possibilities, which was the whole point!
 
Rockethound said:
I see. Maybe the failure rate of JLCR is similar to BP DD but got more-negative "press" due to its newness. I understand its concept, but found stories of chutes not opening. I also read it needs a certain diameter tube, but I've forgotten the value at the moment.
Click to expand...

The current model of JLCR will just barely work in a 38mm tube. I think the problem with the JLCR is that it seems so simple. There are some real things to be careful of when you pack your chute and load your tube. The most important things in my experience is that the chute bundle has to be compact and smooth, and it has to slide easily in the tubes. If the chute doesn't bunch up when you do your shake test and you can blow it out of the tube with the puff test, you're in really good shape. At least if you turn it on. Ask me how I know. :facepalm:
 
Rockethound said:
Only a couple masses have overrides in the file I posted. They are very close to calculated and appear to be actual weights.

There are Darkstar Jr ORK files for DD and short configuration in this thread. A shortened DS Jr will do the job, and the DD version will almost stay under 1500g.

I've been reading about the JLCR. JL says "May work in some 38mm rockets" so I suppose a 54mm is the smallest reliable tube. Maybe it's just what I've read, but it seems Group A is "DD mostly" and Group B is "JLCR mostly". I'll keep reading.

This has been a good thread. People have opened my eyes to new possibilities, which was the whole point!
Click to expand...

I'm a "JLCR mostly" kind of person, mainly because I'm under 18 so no black powder. Most of my JLCR flights are in a 38mm airframe with no issues, even including the Estes style paper shock-cord mount. I've been using a homebuilt 12" hemispherical chute, but I bet I could get a thin 18" chute in if I had to.

I'm personally not a huge fan of fiberglass because of how heavy it is & how much of a pain it is to work with in regards to dust and such, but I can see why people like it- it's nice to have something indestructible, even if it flies like a brick. If it were me (and it is, I'm planning on flying my L1 this weekend) I'd fly something paper with a similar weight, which will end up being bigger and therefore much easier to deal with. (Of course, not heeding my own advice, I'll be stuffing my JLCR and Eggfinder in a 38mm airframe again. Low and slow has its merits, but it only goes so far for me.)

In the end it's completely up to you- I just love that I have a 3" by 5' rocket that I can break 1000' with on small G's.
 
At least if you turn it on. Ask me how I know.
Click to expand...

Aw, boatgeek, that's a deep sigh. And very odd for me to hear, because this thread started with a photo of my first L2 launch. What came before it was an L2 cert launch of a ~3" V2-style squat-rocket. The man and I chatted while Phil was setting up his rocket. At some point he said he didn't know if he'd turned on his JLCR. He disco'd the ignition ("I'm not opening this up live!"), checked the JLCR and it was on. Re-assemble, hook up ignition, and he got his L2. But I have to note that he remembered to check; you didn't have a warning, and some DD setups have sounds that indicate everything that should have continuity does have continuity. Pilot error is the cause 90% of the time.

I know the owner of JLCR reads and contributes here. I don't want anyone to think I'm down on his product. I believe I've identified a way to make it better - an audible confirmation that it's armed and ready. It might exist already... my experience is minimal.
 
I'm personally not a huge fan of fiberglass because of how heavy it is & how much of a pain it is to work with in regards to dust and such, but I can see why people like it- it's nice to have something indestructible, even if it flies like a brick.
Click to expand...

You said that very well. And then I think about how CJ's BH38 won the drag race against the Mongoose 38. There is this "optimal mass" concept that I've read about but need to learn. Who would think the WM BH38 would win against a CF costing 2x? This is part of the intrigue of the hobby.

As I make ORK files for rockets, the (OMG) phenolic Zodiac 54 has a lot going for it. I giggled as it was dragged across a field in David's video, a real testament to its durability. It sounded solid, and it weighs a lot less.

But I know how to finish, repair and refine FG. What to do?!?

(Rhetorical question)
 
A cert rocket just needs to go up on an H and land intact.The closer it is to you the easier it will be to find it. The less systems you will need to obtain cert. You can use motor eject and a main chute no JLCR no DD and get a cert if you pick the right kit and motor. That may sound boring dull and subsonic but that's a reality. If it's a material you like that's a plus on famailarity. Larger diameters will stay lower on same motor. Fiberglass bricks aren't exciting but are really hard to destroy even when the chute is flaming and it's falling fast. See these can CATO, take a swim, find a tree, and a CeRT is a cert. Try it on an H. A cert on a very heavy cardboard and wood hunk rocket counts the same as any fancy kit. A fiberglass kit is cheaper than a Cf kit. Heck a spool rocket might even been cheaper. There were crazy tube fin PVC threads long ago and people laughed but they got certs.

You can also try a MD where you blink, it's gone, and the excitement is cussing at a GPS unit to not crash while its tracking. You won't see a yardstick a mile up. Then you can walk about a mile to retrieve or more if it works. For multistage MD add the complexity of drive halfway across the nation for a twice a year national event with a high enough flying waiver. If you pick the wrong motor it exceeds electronic G ratings and is lost or a total write off. Some people don't even put a tracker outside of a CF tube then they never see it again. Designed two multistage Md L-1. Faster ain't always better. You'll spend more on a fancy FCC tracker and ground station than the cost of a other L-1 kit is. Although the airframe only costs are lower. These either work or entire airframe is total write off of loss of visual/signal can not find fail cert. The initial build and airframe costs are easier but the electronics and performance are very high. On that same H it's a mile up and gone. When electronics get small and precise they get expensive.

scale missiles may piss you off. They will fall between a MD and a highly recommended larger diameter kit Y whatever Y is. They won't have enough packing volume for certain motors and require a lot of lead shot. An RSO may tell you to get another rocket because it flies so horrid compared to usual choices because it needs a pound or more of lead to meet stability and the payload space sucks. They may hit a half mile on an H to a just over a mile on an I. You can still lose sight of these but the more realistic loss is wind drift. Whatever you pick it might be a trash bag or fire hose recovery first flight because rocketry. Oh start with a one bad hawk harness or a quality nylon:Kevlar cord. If cord snaps you fail. Maybe that helps you pick a kit to have general idea of it. Granted this is advice from a dude who failed a cert on an I300. My cord wasn't up to par but the fiberglass rocket survived enough to just need new fillets and recovery gear from 5.4 k ft up.
 
Andrew_ASC said:
A cert rocket just needs to go up on an H and land intact.The closer it is to you the easier it will be to find it. The less systems you will need to obtain cert. You can use motor eject and a main chute no JLCR no DD and get a cert if you pick the right kit and motor. That may sound boring dull and subsonic but that's a reality. If it's a material you like that's a plus on famailarity. Larger diameters will stay lower on same motor. Fiberglass bricks aren't exciting but are really hard to destroy even when the chute is flaming and it's falling fast. See these can CATO, take a swim, find a tree, and a CeRT is a cert. Try it on an H. A cert on a very heavy cardboard and wood hunk rocket counts the same as any fancy kit. A fiberglass kit is cheaper than a Cf kit. Heck a spool rocket might even been cheaper. There were crazy tube fin PVC threads long ago and people laughed but they got certs.

You can also try a MD where you blink, it's gone, and the excitement is cussing at a GPS unit to not crash while its tracking. You won't see a yardstick a mile up. Then you can walk about a mile to retrieve or more if it works. For multistage MD add the complexity of drive halfway across the nation for a twice a year national event with a high enough flying waiver. If you pick the wrong motor it exceeds electronic G ratings and is lost or a total write off. Some people don't even put a tracker outside of a CF tube then they never see it again. Designed two multistage Md L-1. Faster ain't always better. You'll spend more on a fancy FCC tracker and ground station than the cost of a other L-1 kit is. Although the airframe only costs are lower. These either work or entire airframe is total write off of loss of visual/signal can not find fail cert. The initial build and airframe costs are easier but the electronics and performance are very high. On that same H it's a mile up and gone. When electronics get small and precise they get expensive.

scale missiles may piss you off. They will fall between a MD and a highly recommended larger diameter kit Y whatever Y is. They won't have enough packing volume for certain motors and require a lot of lead shot. An RSO may tell you to get another rocket because it flies so horrid compared to usual choices because it needs a pound or more of lead to meet stability and the payload space sucks. They may hit a half mile on an H to a just over a mile on an I. You can still lose sight of these but the more realistic loss is wind drift. Whatever you pick it might be a trash bag or fire hose recovery first flight because rocketry. Oh start with a one bad hawk harness or a quality nylon:Kevlar cord. If cord snaps you fail. Maybe that helps you pick a kit to have general idea of it. Granted this is advice from a dude who failed a cert on an I300. My cord wasn't up to par but the fiberglass rocket survived enough to just need new fillets and recovery gear from 5.4 k ft up.
Click to expand...

Scale rockets or missles don't "fly so horried compared to the usual choices", they should fly as good as any other rocket, the trick is building them so they do fly like any other rocket. Scale models are an advanced type of model rocketry, most RSO's are going to examine the rocket (any rocket) carefully, and ask pointed questions about sims, stability, if you know the CG and CP relationship (its a good idea to mark them on the rocket anyways), and if they have any doubts about the stability its off to the away cell or HPR pads whichever is farther away, its really unusual for an RSO to deny a flight unless it for safety reasons.
 
BS'ng around. Mine flew fine stability wise with a POUND of lead epoxied to nose and recovery was horrid. If you forget the lead there's YouTubeRs oops. Literally there ain't room for a JLCR in a kit I chose already. Not telling him he can't pick a scale missile or a MD but expect more problems and hidden costs.
 
rharshberger said:
Scale rockets or missles don't "fly so horried compared to the usual choices", they should fly as good as any other rocket, the trick is building them so they do fly like any other rocket.
Click to expand...
You can't change the initial design specs of the rocket's natural behavior on a certain range of motors. With enough counter weight they fly fine. It's the performance range they operate at with sometimes very extremely limited packing volume that makes it naturally harder to to recover because you have less packing volume for more recovery assisting objects compared to rockets that ate more motor ranges and have more packing volumes and don't need a bunch of lead to make an RSO happy. Some of the scale missiles are so short and narrow diameter you can't fit an L-2 casing or a DD deploy upgrade. It's not that they are bad it's they are different and I think this guy may not want that. So I let him know upfront how they behave.
 
So it's not that you can't recover a rocket that goes to 2.6 k ft or 5.4 k ft on a single main chute, but without a JLCR it's much much harder for whatever the flying field wind conditions are compared to a Drago or whatever that will fly lower on that same motor and have a JLCR, Dual deploy, and room for multiple trackers for a given crosswind or given winds aloft for a standard descent rate. Then it's up to the flyer to know the difference between what the flying limits are on the model when they are brand freaking new and basically some scale missiles are a great way to mess up when your new and don't know much compared to rockets that may be more tolerant of wind conditions for example and have more payload capacity and motor selection in a class range or two. You don't think a mile up is far until you see a standard descent rate and lateral drift on a realist 7mph wind. And as a new guy myself that was real hard to understand about the hobby at first. Some people were picking certain kits and motors to make the cert flight easier for a broader range of flying field conditions. Where somebody might get a cert on a drago in a 5-10 mph wind. I may have to limit to 3-5mph for a chance of seeing a RB-05A single main apogee deploy rocket again if I don't fly a tracker.
 
Canvas phenolic finishes up pretty easy. Coat or two of primer, sand, paint.

Repair isnt too tricky, combination of techniques. I used to hang deployment charges on wires loose in the booster. Well, I had one set off the other in my villain and 4g of ffffg go off instead of 2, and the way it was contained, cracked my villain booster. Easy fix, drilled holes at the ends of the cracks, covered the interior with epoxy and slid a coupler in.

And Nd then I switched to charge canons on the bulkheads. Much better solution.
 
rZ7WLQf.jpg


Packing Volume. There's a H219 DMS, A 38/480 casing, 12ft of Kevlar, 12" Nomex, a 24" IRIS drogue and this kit basically maxed out it's volumetric payload.

wCaS1a9.jpg

It all fits just barely but forget cramming a JLCR into it, I may try to get one and shoehorn it. You guys see how little space this has. That's what I don't recommend about scale missiles like an RB-05A.
 
Lots of good thoughts here. I find myself thinking about following David's suggestion - getting a DD rocket, flying SD without the av bay and payload to cert, then working DD into the picture. Madcow Adventurer 2.2, Darkstar Jr and Zodiac 54 (with the 31.5" booster tube + DD) are on the list at this time. Thanks for the scale missile background - the Nike Smoke caught my eye and may be in the long-term lineup.

But I'm off to see today's SARG launch. Heaven knows what new ideas will come from that.
 
Nike Smokes are popular. I bought a Wildman Sandhawk Scale kit after flying the RB-05A, on a Black Sat sale. I haven't built Sandhawk yet but it's 3-4x as long as the RB-05A for same price and came with a dual deploy tube as long as the RB fuse tube. Basically the Sandhawk will accept anything from an AT/CTI H class to 38-1200 K class Loki. If you buy a longer scale sounding rocket like a Black brant, Nike, Sandhawk you won't have packing problems compared to a RB-05/Maverick/"Short Stumpy Scale Rocket" an RSO exclaimed.
 
Rockethound said:
I know the owner of JLCR reads and contributes here. I don't want anyone to think I'm down on his product. I believe I've identified a way to make it better - an audible confirmation that it's armed and ready. It might exist already... my experience is minimal.
Click to expand...

I have no personal connection to Jolly Logic, and I wanted to mention that I think JLCR is one of the greatest innovations for model rocketry in recent times. Almost everyone in my club uses it. It's hassle-free and about 100% reliable in our experience -- unless user error -- which is minimal if we just follow JL's simple full-color booklet. I used it for L2 cert to 3500+ feet on a windy day, and the JLCR was flawless. Rocket landed softly just a couple hundred yards away -- rather than floating a mile or more and getting lost -- no tracker or DD needed. Maybe that's too simple, but hey it works.
 
I've used TeleGPS for the student multistage L-1 UTC SEDS 2017 comp and placed 3rd nationally. We found a sustainer payloAd 1.7km away in a tree from 15mph winds after a sustainer CATO from 3,773ft. Winds aloft at 11k were 30mph +.Booster was in a freakin' pond. I don't want to think how far it would've drifted from the predicted 11kft if it actually had made that not Cato. You'll hear nostalgic sh*t like "Wanna lose a rocket today, you might find it in the next town three miles down the road!" And I wouldn't have doubted that logic. That was a real possibility. Some rockets that don't have diameter for JLCR suffer from lost syndrome. Real eye opener to me about wind drift. Hard to see a yardstick 1.7km on ground. Only dinky 29mm H motors. We weren't even trying big H motors we were trying to stay under waivers out east after going all out west once. Some universities rented light airplanes to look for lost rockets and never found them. One year Mizzou put a tracker in a CF rocket about 4" diameter and never found it CF not RF transparent. Lol. KN4EOU out.
 

Similar threads

zeketrimmer
What is the biggest 29mm cti motor you can use for an l1 cert rocket?
Replies
14
Views
492
-Slick-Ice
S
B
Question on allowable reuse of parts for an L3 Cert Rocket
Replies
17
Views
913
Handeman
Handeman
Rocketholic
Pro Series II 2.5" Tubes - Supersonic?
Replies
11
Views
389
lr64
L
DJRNY
Yet another Zephyr build thread? / Zephyr L1 cert motor?
Replies
16
Views
538
DJRNY
DJRNY
COSTransplant
Successful L1 Cert Flight
Replies
22
Views
1K
Rob Campbell
Rob Campbell

Latest posts

Back
Top