Level 1 Cert rocket

Handeman

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I helped a Jr. flier this summer with a 4" dia, LOC rocket that has 1/8 inch thick fins. Upon landing a corner of one of the fins was damaged. The rocket was still able to fly again, and dispite the RSO's best efforts to tear the corner off, it was intacked. The Jr. Flier has a repair project ahead of them.
I had that happen to a 4" Patriot with 1/8" thick fins. It broke a 1" x 3/4" piece out of one fin tip. Since it really didn't affect the CP that much, I just continued to fly it with the fin with the broken piece until another fin broke and needed a repair.
 

Zeta

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I think we need to recognize the design inside the LOC kits. The rings, fins, MMT etc. all epoxied together are very strong, I have no doubts....
 

Black Bart

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if im building a 6 lb rocket and plan on L-2 cert a 54 mm motor tube give you more options.
i have a 4" iris with EB 3.9 e bay that i fly with a 54 mm -38 mm adapter.
 

thzero

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I think we need to recognize the design inside the LOC kits. The rings, fins, MMT etc. all epoxied together are very strong, I have no doubts....
Huh? Its no different than any other kit design. As as noted, its not that the kit can't handle the H motor.
 

thzero

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if im building a 6 lb rocket and plan on L-2 cert a 54 mm motor tube give you more options.
i have a 4" iris with EB 3.9 e bay that i fly with a 54 mm -38 mm adapter.
Well I ended up doing mine with a 38mm motor, but yeah depending on the rocket a 54mm can give you a few more options.
 

Black Bart

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Well I ended up doing mine with a 38mm motor, but yeah depending on the rocket a 54mm can give you a few more options.
i L-1 with a Apogee Zephyr H 100W. i fly it at every launch with 29 mm H motors depending on the wind. i wish that i did not glue in the tube coupler to put in a e bay. May build a new Zephyr $ 99.99. plus the Apogee e bay much lighter than the LOC. One all thread and no iner tube just rings.
 

Zeta

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Huh? Its no different than any other kit design. As as noted, its not that the kit can't handle the H motor.
actually I think they are designed such that the MMT, rings, and fin assembly can be built first and then slipped into the airframe. the advantage being that it is very easy to make really nice filets and get all the parts connected. The rings can be epoxied on to the leading and trailing edges of the fins. So they are a bit unique in this regard.
 

DRAGON64

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I was progressive on each of my cert flights;
2.6" for L1 (Aerotech H128);
4" for L2 (HyperTEK J300):
5.5" for L3 (Loki M1882)
They went 1,700ft, 3,333ft and 6,400+ respectfully.

I too was given the advice of low draggy cert flights. But I flew my rockets the way I envisioned them to be flown, and in such a way that I could see the whole flight start to finish.
 

cwbullet

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I was progressive on each of my cert flights;
2.6" for L1 (Aerotech H128);
4" for L2 (HyperTEK J300):
5.5" for L3 (Loki M1882)
They went 1,700ft, 3,333ft and 6,400+ respectfully.

I too was given the advice of low draggy cert flights. But I flew my rockets the way I envisioned them to be flown, and in such a way that I could see the whole flight start to finish.

I switched fiberglass and heavy on my level 2:

Level 1 - 5.5" LOC Minie Magg (2009); 1000+ om
Level 2 - 4" PR Broken Arrow(2010); 3000+ on a J
Level 3 - 10 inch Nike Smoke(2011): 5000+ on an M2550
 

Handeman

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Oh, I'm sure the I-Roc can handle the H550 fine. It's more the situation. Earlier we didn't know the OP's experience. For all we knew it could've been only Estes easy builds. Also the step up and build demands for a rocket that flies off a G64 is imo MUCH lower than that of a H550. Wouldn't you agree?
No, I wouldn't agree.
My opinion is if you can build a rocket that can handle a G64, building the bigger I-ROC with the naturally required bigger fillets, etc. required for the bigger parts is almost a given that it will hold up to the H550. I would expect the rocket that held up to the G64 would almost certainly hold up to the H550 also.

Over the years I've come to see that most people totally over estimate the loads and forces on cardboard rockets and the required build methods needed to fly on higher power motors.
The only rocket I ever "shreaded" because the motor was too large was one printed out on a sheet of paper and constructed with paper glue. It flew fine on a A8-3, but ripped the fins off when I couldn't resist flying it on a C6-7. The body tube held up fine. Just the fact a paper rocket made totally from a single sheet of printer paper can fly on a A8-3 shows that the structure of most rockets are much stronger than most people give them credit for.

I've flown every one of my 24mm Estes D rockets on composite F24W or F39T motors and everyone had held up fine, including the Renegade D with its side tubes and fin pods. I think most of us underestimate the strength and durability of cardboard rockets.
 

KenECoyote

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No, I wouldn't agree.
My opinion is if you can build a rocket that can handle a G64, building the bigger I-ROC with the naturally required bigger fillets, etc. required for the bigger parts is almost a given that it will hold up to the H550. I would expect the rocket that held up to the G64 would almost certainly hold up to the H550 also.

Over the years I've come to see that most people totally over estimate the loads and forces on cardboard rockets and the required build methods needed to fly on higher power motors.
The only rocket I ever "shreaded" because the motor was too large was one printed out on a sheet of paper and constructed with paper glue. It flew fine on a A8-3, but ripped the fins off when I couldn't resist flying it on a C6-7. The body tube held up fine. Just the fact a paper rocket made totally from a single sheet of printer paper can fly on a A8-3 shows that the structure of most rockets are much stronger than most people give them credit for.

I've flown every one of my 24mm Estes D rockets on composite F24W or F39T motors and everyone had held up fine, including the Renegade D with its side tubes and fin pods. I think most of us underestimate the strength and durability of cardboard rockets.
Losing My Mind GIF by systaime

Haha! I've thought it over and I'm now in more agreement with you guys. :)đź‘Ť
 

kramer714

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the specs say they are 1/8", while its not the force of the motor I am concerned with, it is the landing.
Yup, or the car ride...

Great choice for a level 1. One thing to think about for your level 1, really fast motors 'sometimes' are harder to get the delay grain lit well. A slower motor may be more forgiving. I'm guessing your delay is going to be kind of short.

Side note; short fat rocket on a VERY fast motors are fun, I launch my 4" fibergoblin (with electronics) on a J1799 - Fun!!! something like 50G's
 

bjphoenix

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Over the years I've come to see that most people totally over estimate the loads and forces on cardboard rockets and the required build methods needed to fly on higher power motors.
Nobody actually does design calculations on their rockets, we don't know what doesn't work until it doesn't work. I recall many years ago when we had the high thrust B3 motors people talked about weak motor mounts and the possibility of a motor going through the rocket and leaving the rest of it setting on the pad. I don't know if I ever heard of that happening but at our last LPR launch I saw a C6 go up into the airframe of an Estes model.
Somebody was talking about H550- max. thrust of about 150 pounds. Some of that force goes into accelerating the motor itself but in a reasonably heavy rocket a good part of that thrust would be transferred from the motor to the mount. I dare say that all of my MPR built with LOC tubing and epoxy would carry that load but I'm not going to test that, I suppose it's not out of the question that a mount could fail under that load.
I really think a rocket shredding could be more a factor of velocity than acceleration. A G rocket of the right weight could certainly go faster than a larger rocket with H550. I think this is the same thing as Handeman said, just because you have a high power motor doesn't mean it requires exotic materals.
 

thzero

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Nobody actually does design calculations on their rockets, we don't know what doesn't work until it doesn't work. I recall many years ago when we had the high thrust B3 motors people talked about weak motor mounts and the possibility of a motor going through the rocket and leaving the rest of it setting on the pad. I don't know if I ever heard of that happening but at our last LPR launch I saw a C6 go up into the airframe of an Estes model.
Somebody was talking about H550- max. thrust of about 150 pounds. Some of that force goes into accelerating the motor itself but in a reasonably heavy rocket a good part of that thrust would be transferred from the motor to the mount. I dare say that all of my MPR built with LOC tubing and epoxy would carry that load but I'm not going to test that, I suppose it's not out of the question that a mount could fail under that load.
I really think a rocket shredding could be more a factor of velocity than acceleration. A G rocket of the right weight could certainly go faster than a larger rocket with H550. I think this is the same thing as Handeman said, just because you have a high power motor doesn't mean it requires exotic materals.
Uh... Ok then
 

Handeman

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Nobody actually does design calculations on their rockets, we don't know what doesn't work until it doesn't work. I recall many years ago when we had the high thrust B3 motors people talked about weak motor mounts and the possibility of a motor going through the rocket and leaving the rest of it setting on the pad. I don't know if I ever heard of that happening but at our last LPR launch I saw a C6 go up into the airframe of an Estes model.
Somebody was talking about H550- max. thrust of about 150 pounds. Some of that force goes into accelerating the motor itself but in a reasonably heavy rocket a good part of that thrust would be transferred from the motor to the mount. I dare say that all of my MPR built with LOC tubing and epoxy would carry that load but I'm not going to test that, I suppose it's not out of the question that a mount could fail under that load.
I really think a rocket shredding could be more a factor of velocity than acceleration. A G rocket of the right weight could certainly go faster than a larger rocket with H550. I think this is the same thing as Handeman said, just because you have a high power motor doesn't mean it requires exotic materals.
You're right about not doing design calcs. I certainly don't, not for things like shear strength on motor mounts, etc.
I also think cost has something to do with it. If you don't build a LPR strong enough and it comes apart during flight, it isn't a high cost to repair or replace. If that happens on a HPR, it can be much more costly. Because of that, I think most people want to overbuild and make sure the rocket will survive not only a nominal flight, but some of the anomalies that can occur like early ejections, tangled main, etc. I know I think along those lines when I build. Then again, flying on the east coast with the lower COAs, light and high altitudes isn't something most of us are trying for. Heavy and lower is usually considered a good thing. Trying to keep an N or O motor under 10K ft. can only be done that way.
 
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