Do you consider MPR a pre-requisite for HPR?

[thzero]

As someone currently using a kit for my L3 build, and from people I've talked to, I would say very few are putting it together stock like an Estes kit. Most are using their own build techniques, especially since a large number of kits that can handle L3 sized motors don't come with instructions anyway.

Or are getting a kit for "cheap parts". Mine sits on the couch.

 

[loopy]

Or are getting a kit for "cheap parts". Mine sits on the couch.

Exactly. A lot of kits have everything you need for your scratch build, so really all you have to do is cut new fins or what not.

 

[loopy]

Tripoli is clear: "The rocket may be either a kit or scratch-built." NAR doesn't mention it either way. L3 candidates should adopt a 'no surprises' stance when dealing with your cert team.

https://tripoli.org/content.aspx?page_id=22&club_id=795696&module_id=479470

https://www.nar.org/high-power-rocketry-info/level-3-certification/

Yup. Which is why you get your plans approved by the L3CC or TAPs before you start.

 

[cerving]

For a L3 cert you also need to document your build, provide simulations, and provide some sort of diagram/schematic of your AV bay electronics layout. The idea is that you are submitting a project proposal first, then the documentation supporting your build. Highly doubtful that this could be done in one weekend, especially at a launch.

 

[ep29030]

Kits are just pre-cut parts. There is no guarantee of stability even with kits—I believe most of us have a kit that requires added weight to be stable with certain motors. For L3, you still have to do the simulation to show where the CG/CP relationship is for your kit. Recovery system and av bay components often must be designed by the builder—most HPR kits have minimal to no instructions for assembly. If it weren’t for kits, there would be alot of people who could not certify because they lack the shop equipment for fabrication. I have equipment for making av bays, fins, etc but 70% of my rockets start out as kits — saves me time.

“Scratch-built” = I bought the electronics, airframe/motor tubing, fin stock, shock cord and sleeve, Nomex pad, parachute, centering rings, allthread and nuts/washers. In reality, very few people truly “scratch-build” rockets. Fun to do, takes loads of time which most of us lack.

 

[loopy]

Kits are just pre-cut parts. There is no guarantee of stability even with kits—I believe most of us have a kit that requires added weight to be stable with certain motors. For L3, you still have to do the simulation to show where the CG/CP relationship is for your kit. Recovery system and av bay components often must be designed by the builder—most HPR kits have minimal to no instructions for assembly. If it weren’t for kits, there would be alot of people who could not certify because they lack the shop equipment for fabrication. I have equipment for making av bays, fins, etc but 70% of my rockets start out as kits — saves me time.

“Scratch-built” = I bought the electronics, airframe/motor tubing, fin stock, shock cord and sleeve, Nomex pad, parachute, centering rings, allthread and nuts/washers. In reality, very few people truly “scratch-build” rockets. Fun to do, takes loads of time which most of us lack.

Exactly. Also, I'm not that creative...My only scratch builds have been upscales of old Estes kits because I'm not someone that is creative enough to come up with my own design for a rocket. No reason to prohibit people without a good imagination from certifying higher levels...lol

 

[bad_idea]

For a L3 cert you also need to document your build, provide simulations, and provide some sort of diagram/schematic of your AV bay electronics layout. The idea is that you are submitting a project proposal first, then the documentation supporting your build. Highly doubtful that this could be done in one weekend, especially at a launch.

It's been done before. I know of an L3 that was built and successfully flown for certification at a multi-day launch. Because TAPs were on the field observing the build, documentation was able to be kept to a minimum.

That happened some years back, but looking over the current rules, it looks like this would probably still be possible given TAP availability and comfort with the plan, though I doubt many people would or could do it that way.

Also, I'm not that creative...My only scratch builds have been upscales of old Estes kits because I'm not someone that is creative enough to come up with my own design for a rocket. No reason to prohibit people without a good imagination from certifying higher levels...lol

I scratch build nearly all my rockets, and I never really do much that's creative, I just design parts to do what is needed when built from available components and stock, then put parts where they seem to fit. (Many kits are designed like that too, of course.) Not saying this to advocate that L3s be scratchbuilt, merely to encourage you that scratch building a rocket is probably not outside your skills if you wanted to do it.

 

[techrat]

I scratch build nearly all my rockets, and I never really do much that's creative, I just design parts to do what is needed when built from available components and stock, then put parts where they seem to fit.

I scratch build many many rockets, and I rarely ever consider it to be a purely creative process, probably because I don't design it first in my head (nor do I do Openrocket Sims); I just start building and do "what looks right" -- when I used LEGO as a kid, I built things that way as well, just started putting bricks together and it just sort of took shape on it's own. MAYBE that's a creative process, like when artists start a painting with no idea how it's going to turn out until they stop and say "it's finished".

But I always build that way -- I start with a general idea of what I want but honestly, when I'm finished, I'm just as surprised as anyone else regarding the final product.

 

[loopy]

It's been done before. I know of an L3 that was built and successfully flown for certification at a multi-day launch. Because TAPs were on the field observing the build, documentation was able to be kept to a minimum.

That happened some years back, but looking over the current rules, it looks like this would probably still be possible given TAP availability and comfort with the plan, though I doubt many people would or could do it that way.

I scratch build nearly all my rockets, and I never really do much that's creative, I just design parts to do what is needed when built from available components and stock, then put parts where they seem to fit. (Many kits are designed like that too, of course.) Not saying this to advocate that L3s be scratchbuilt, merely to encourage you that scratch building a rocket is probably not outside your skills if you wanted to do it.

I've done a few upscales, but that's about as creative as I get with it...lol...I just mean that I'm not good at coming up with my own fin designs and overall rocket designs. I'm fine with upscaling. My point is that being able to design your own scratch build isn't something everyone can do.

 

[ep29030]

IT seems that most of my scratch-builds tend to be upscales as well. Just started on a 3” Citation Patriot upscale with carbon-covered balsa fins. I will often cut parts from my stash to save time (no waiting for parts to arrive) rather than saving money.

 

[Titan II]

To restate the general question, do you consider MPR a pre-requisite for HPR?

Absolutely not.

 

[Wrightme43]

Off Grid Gecko said:
To restate the general question, do you consider MPR a pre-requisite for HPR?

Following the rules as written? No.

For me personally, Yes.

I have been studying, and have taken the L2 test twice. I will keep taking it untill I can get it lodged in my brain before I attempt my first high power build for L1. I feel like for (me only) it is important to build skills and experience in a small step manner. I hand load rifle for accuracy, I build strong beautiful things out of hardwood, I have built mild performance engines for fun from a bare block and crank. I started to get my private pilots license, but with all my kids I am just priced out of that dream. Some of these skills are transferable, but there is no substitute for experience to me. I want to build, and fly things I am proud of, and have the people that inspect my 1st high power rocket know before it is put in thier hands that it will pass inspection, and that my actions and behavior from start to finish will be safe and contain no surprises.

This is just my thoughts and opinion on how I need to do this. Please do not think I am telling anyone else what to do.

I am so excited about the progress I have made so far. My first club launch was very rewarding, and educational, the next is September 9th weather permitting.
I found Music City Missle Club as well, and they have a BIG field after crops are down.
This has just been a blast, but without help, and your build threads, and discussions I would not understand 1/4 of what I do now.

Thank you!
Steve

 

[Steve Shannon]

Off Grid Gecko said:
To restate the general question, do you consider MPR a pre-requisite for HPR?

Following the rules as written? No.

For me personally, Yes.

I have been studying, and have taken the L2 test twice. I will keep taking it untill I can get it lodged in my brain before I attempt my first high power build for L1. I feel like for (me only) it is important to build skills and experience in a small step manner. I hand load rifle for accuracy, I build strong beautiful things out of hardwood, I have built mild performance engines for fun from a bare block and crank. I started to get my private pilots license, but with all my kids I am just priced out of that dream. Some of these skills are transferable, but there is no substitute for experience to me. I want to build, and fly things I am proud of, and have the people that inspect my 1st high power rocket know before it is put in thier hands that it will pass inspection, and that my actions and behavior from start to finish will be safe and contain no surprises.

This is just my thoughts and opinion on how I need to do this. Please do not think I am telling anyone else what to do.

I am so excited about the progress I have made so far. My first club launch was very rewarding, and educational, the next is September 9th weather permitting.
I found Music City Missle Club as well, and they have a BIG field after crops are down.
This has just been a blast, but without help, and your build threads, and discussions I would not understand 1/4 of what I do now.

Thank you!
Steve

Great answer!

 

[86mustang408w]

I mean I think yes and no. It depends on the rocket. Some guys underestimate an F motor let alone an H, I guess it depends on the rocket and what motor you use. But the build techniques are far different, it confuses many when starting out. Even myself...lol.

 

[rcktnut]

Yup. Which is why you get your plans approved by the L3CC or TAPs before you start.

........................................... and that doesn't guarantee a successful flight either!!
I witnessed this rockets L3 flight attempt on a N2000, went straight up came straight down, none of the ejection charges fired.

 

[Banzai88]

........................................... and that doesn't guarantee a successful flight either!!
I witnessed this rockets L3 flight attempt on a N2000, went straight up came straight down, none of the ejection charges fired.

View attachment 603010

I've seen an alarming number of L3 attempts fail, many in dangerous and spectacular manners. Seriously makes me question the process, or at least the discretion of the L3CC/TAP.

I've seen some who CLEARLY have more first attempt success candidates than others, and those that'll sign on to just about anything/anyone have more 2x and 3x attempt candidates.

So, to my mind, choice of oversight is as key a component to certification as glue or parachute selection.

 

[smstachwick]

[snip] So, to my mind, choice of oversight is as key a component to certification as glue [snip]

Pray we don’t get threads about that too!

 

[Banzai88]

Pray we don’t get threads about that too!

Won't need 'em. Spend a season or two at any average rocket field that has L3 friendly waivers and anyone with half a brain can figure out the serious folks from the cowboys, and choose accordingly.

 

[RimshotRed]

I couldn't think of a clever title that encapsulated what I really want to ask, but I've been thinking on this lately.
First, this thread is not to demean, undermine, or discourage using MPR as a stepping stone to larger rockets. I'm simply seeking some concrete clarification and different people's opinions on the matter. That said.
I see it quoted quite often that experience should be gained in a hierarchical order. Generally LPR first, then "stepping up" to mid power, then onto L1 and L2, each in their own category. I won't discuss L3 here.
I see the merit in someone new to rocketry starting with low-power kits. I think a lot of us started there as kids, or even as adults. There's a lot to rocketry, and the LPR stuff offers a low barrier to entry, both in terms of cost and difficulty. It's an "easy" way to get familiar with rocketry, you can fly just about anywhere, and unless you live near an airstrip there is no need to call the FAA or the closest tower.
High power is obviously a different animal. I can Elmer's glue a LPR rocket from paper in a matter of hours and it will fly just fine. Obviously we don't want that kind of construction mentality when dealing with 10-s to 100-s of pounds of thrust, or higher as the scale progresses.
Now, MPR is in the middle. I know I had a kit or two that flew on D's and E's as a kid, just fell out before I got to them "big" F motors that I would drool over. They do need to be constructed with some minimal amount of care, but for the most part, they mimic the smaller LPR build process with a touch more attention to detail. Let me stop there for a minute.

So, not looking for anyone to argue with anyone else, just your own opinions on this. Should MPR find it's way into everyone's fleet before considering a high-power build at all? Why? Why not?
Some of the why's that I can think of quickly:
-More familiar with stronger building techniques
-More time to learn about bond strength and think about how much stress is applied to a rocket in different places.
-Fly a little higher and cement the idea that you need more space with more power.
-Failures are lower risk than with HPR (though things can still fail even with a careful build)

And finally, I don't see MPR as a "requirement" so much. I see it as a stepping stone. People come to our hobby from engineering disciplines sometimes, sometimes they are already expert model builders. Some have flown RC helis or race RC cars and understand a lot of concepts the average guy off the street wouldn't. Etc. Some people read a lot more than others (how many people visit this forum frequently to learn what they need to know without ever signing up?)
To me this is more of a case-by-case thing. To my brother I recommended him to get a little launch rod and a small kit. He knows how glue works and has built models before. I also recommended going with a small motor and explained how easily these things can get lost. And he did this as a kid at one point as well. But getting back into the hobby, it's the easiest way. I might also recommend MPR to him if he wants to go further so that he can learn some of the engineering concepts specific to rocketry.
But I don't consider these recommendations a one-size-fits-all solution. Someone who understands engineering and has built and flown several small rockets on C and D engines probably has the basics down, and might select more appropriate glue, but otherwise could be turned loose on a bigger build, especially if they are simulating all of their designs on the computer already.

Just some thoughts, sorry so long winded. What are your thoughts? To restate the general question, do you consider MPR a pre-requisite for HPR?

I think someone who is just getting into Rocketry should consider progressing in steps from a beginner LPR to a more difficult build in the LPR and adding a Mid Power before jumping to HPR level. this way the new Rocketeer can gain experience as well as confidence in their skills as they progress. I do not think it should be a requirement just a friendly suggestion.

 

[gldknght]

Oops

 

[Art Upton]

When I built my L3 Booster Bruiser Rocket from LOC with 98mm mount, I used the Same Estes saying; A, then B , C then the mighty D

Started with small K to get the recovery all figgured out.. Then a Full K and it worked then same. Then a full L motor ...

And then the 98mm long 15 second M motor for my L3 Cert... Doing the "Steps" to learn.

 

[Daddyisabar]

Won't need 'em. Spend a season or two at any average rocket field that has L3 friendly waivers and anyone with half a brain can figure out the serious folks from the cowboys, and choose accordingly.

Singing:

WHERE HAVE ALL THE COWBOYS GONE?

I'll deploy the landry,
If you'll do all the sims...

 

[smstachwick]

When I built my L3 Booster Bruiser Rocket from LOC with 98mm mount, I used the Same Estes saying; A, then B , C then the mighty D

Started with small K to get the recovery all figgured out.. Then a Full K and it worked then same. Then a full L motor ...

And then the 98mm long 15 second M motor for my L3 Cert... Doing the "Steps" to learn.

I’ve also elected to make practice flights part of my certification process.

My Astrobee D has flown on an F67W and I have a pair of G74Ws earmarked for further flight tests. I’m glad I did too, I busted a fin on the F flight so I redid the fin and upgraded one of the chutes to protect the rest of the fins.

I had a certification motor in mind but it looks like I’ll end up being somewhat flexible on launch day.