Do you consider MPR a pre-requisite for HPR?

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chuck2200

Member
I believe it is wise to build a few MPRs before trying to qualify for Level HPR.
It gives you experience in building larger airframes and stronger fins, as well as providing an avenue, IF desired, to learn the use of electronics for recover deployment. But the biggest advantage - in my opinion - is that the flyer can select a smallish HPR design, build it and fly it as a MPR to gain experience with it before that all important L1 Certification flight.

ChicagoDave

Well-Known Member
TRF Supporter
Required? No. But I still fly MPR at almost every launch. In fact I still fly the rocket I used to get my L1 on Gs quite often.

OverTheTop

Well-Known Member
The simple fact is that I went straight from D to H without ever flying anything in between, so obviously the experience of building and flying MPR wasn’t truly necessary. I never even saw a G motor until the day before I certified L1. In fact I might not have flown a G until after I was L3. That doesn’t say anything good or bad; I was just enjoying HPR.
This is exactly my progress to HPR. So is it "Great minds think alike" or "Fools seldom differ"?

I still don't fly anything between a D and a K.

Off Grid Gecko

Well-Known Member
Thanks everyone for the terrific posts so far. The personal stories have been full of insight and the more direct answers qualified by the poster. I think there's much wisdom and experience in this thread and look forward to seeing how it evolves. Some really good points on both sides!

Steve Shannon

Well-Known Member
TRF Supporter
This is exactly my progress to HPR. So is it "Great minds think alike" or "Fools seldom differ"?

I still don't fly anything between a D and a K.
I’m sure it’s great minds!
I find myself flying a lot of small motors just to fly.

Tim51

Well-Known Member
Everyone has different learning patterns. IMHO the fact that legally there is no such thing as Mid Power, but as a rocketry community we've created that distinction must mean something for at least a sizeable portion of us: eg. it serves a psychological and/or practical purpose etc, in some cases a stepping stone, but also a category in its own right.
In point of fact I went straight from flying D motos to HPR, but I did start clustering Estes and Klima D motors just prior to deciding to take the leap. It was then that someone told me my clusters were 'Mid Power'. Even so, I was still using LPR techniques. For me, my L1 cert build was my first time using epoxy, plywood, kevlar and reloadable motors. Now, 5 years into HPR, I confess I have an MPR itch, and I'm considering an E-G impulse build...

scschulte

Member
I would recommend an Aerotech DMS for an L1 flight. Eliminating the engine assembly limits variables. All you have to do is drill the delay. There are plenty of H DMS engines to choose from.
Thanks for your post because I’ve been a CTI kinda guy since 2009 but will now check out the Aerotech DMS. Steve on 8 July 2020

Alan R

Well-Known Member
I believe it is wise to build a few MPRs before trying to qualify for Level HPR.
It gives you experience in building larger airframes and stronger fins
Agreed.

In my mind MPR is 29mm F/G motors. Even though you can buy F rockets from Estes they require that you learn some new building techniques not usually present in LPR. Since I'm not even an official HPR rocketeer yet (soon, soon) this is just my personal opinion.

Some things in MPR that are not usually present in LPR:
Through the wall fins. Attaching these require some new skills you don't learn with small rockets
Plywood CR's and fins.
Using epoxy glue. Yes, you can build with titebond, but starting at 29mm, epoxies are recommended for high stress points: motor mounts and fins.
Various methods for shock cord attachments. They are no longer paper tabs white-glued to the inside of the BT.
Electronics. With F/G power you can lift a little more weight and start learning something about attaching/using something more than a small altimeter.

I don't think it's a requirement to go through the MPR stage to reach HPR, but if you don't, your first HPR is going to be using some radical new build techniques you haven't seen before.

ThirstyBarbarian

Well-Known Member
TRF Supporter
I think it’s generally best not to skip motor classes and to take your time gaining experience and actually enjoying the process.

That said, it’s not a requirement. I went to a multi-day club launch about 6 years ago where a group of 25 or so college students were there to cert. They had a mentor who had guided them through their builds and was there to advise on their flights and sign off their certs.

They had all built exactly the same model of simple L2 capable fiberglass rocket. On the first day, they all flew their L1 flights on the same type of DMS I motor. They did their L2 written test. And on the second day, they all flew their L2 flights on the same kind of DMS J motor.

I’m sure for a lot of them, those were their first flights ever. So after building one rocket with supervision and doing 2 motor-deploy flights on single-use motors, most of them left with an L2 cert and the legal right to buy and fly motors up to L impulse.

That’s not really what I would recommend, and it seems like it shortcuts the learning process that is supposed to be part of the cert process, but it can be done that way.

Off Grid Gecko

Well-Known Member
Agreed.

In my mind MPR is 29mm F/G motors. Even though you can buy F rockets from Estes they require that you learn some new building techniques not usually present in LPR. Since I'm not even an official HPR rocketeer yet (soon, soon) this is just my personal opinion.

Some things in MPR that are not usually present in LPR:
Through the wall fins. Attaching these require some new skills you don't learn with small rockets
Plywood CR's and fins.
Using epoxy glue. Yes, you can build with titebond, but starting at 29mm, epoxies are recommended for high stress points: motor mounts and fins.
Various methods for shock cord attachments. They are no longer paper tabs white-glued to the inside of the BT.
Electronics. With F/G power you can lift a little more weight and start learning something about attaching/using something more than a small altimeter.

I don't think it's a requirement to go through the MPR stage to reach HPR, but if you don't, your first HPR is going to be using some radical new build techniques you haven't seen before.
Cept for idiots like me that like TTW fins enough to stick them on A-powered rockets It's just better all around (and alignment is easier, imo), until you snap a fin instead of it simply popping off the rocket where you can re-glue it.
Just having some fun on that remark because it made me smile. I definitely agree that there is a lot to learn, and more still once that fist HPR cert is in your back pocket, but I also went to school with guys that build homemade lasers, telescopes, and other crazy stuff that the "normal" crowd wouldn't bother about.
I always have trouble with the concept that epoxy is a skill that must be learned, but maybe that's just because I've been using it for decades and I forget that other people don't touch the stuff, and it does take quite a bit of reasoning to know where the stress points are going to be, if the eye screw is going to hold, etc. etc. etc.
Thanks for all the good points; some more stuff to think about.

Spitfire222

Well-Known Member
Just to add my personal thoughts on this as someone progressing through the impulse classes: I've been building various types of models for long enough that I could likely successfully go straight from LPR to HPR, having enough experience with the materials and building methods that go with it. But I've been finding that it's enjoyable to experience a new motor impulse as it provides a similar rush as when I launched a rocket for the first time. If I jumped from D motors to Level 1, I'd be missing out on that feeling provided by the MPR range. Sure, that first HPR launch would be impressive, but then if I wanted to go back to MPR, there wouldn't be that initial feeling of excitement since I would have already experienced something more powerful.

I hope that makes sense. I guess I'm saying that I'm trying to enjoy each step up to a new motor impulse class, and if I jumped straight to HPR, I'd be missing out on a few of those incremental step-ups.

OKTurbo

Well-Known Member
Personally I think the progression thru ‘mid power’ helps you think more about safety and stability issues. When I was building and flying low power I never gave thought to CG and CP, or even recovery systems. I just built the kit and had a blast.

As the rockets get bigger and faster there is much more potential for something to go wrong. Mid power gives you a chance to build some rockets where you really need to check stability before put that ‘big’ G reload motor in it.

Off Grid Gecko

Well-Known Member
Just to add my personal thoughts on this as someone progressing through the impulse classes: I've been building various types of models for long enough that I could likely successfully go straight from LPR to HPR, having enough experience with the materials and building methods that go with it. But I've been finding that it's enjoyable to experience a new motor impulse as it provides a similar rush as when I launched a rocket for the first time. If I jumped from D motors to Level 1, I'd be missing out on that feeling provided by the MPR range. Sure, that first HPR launch would be impressive, but then if I wanted to go back to MPR, there wouldn't be that initial feeling of excitement since I would have already experienced something more powerful.

I hope that makes sense. I guess I'm saying that I'm trying to enjoy each step up to a new motor impulse class, and if I jumped straight to HPR, I'd be missing out on a few of those incremental step-ups.
Makes perfect sense. I'm the same way with my favorite video games. When I start a new save on Kerbal Space Program I always want to make sounding rockets and jet planes, and I like launching tiny satellites as efficiently as possible.
OTOH, after I finished my L1 build, all I wanted to do was build MPRs, so I bought a Mean Machine kit to bash up into several smaller LPR/MPR rockets. They're cheaper to fly and easier to find a launch zone for. Also cheaper to fine tune filling and sanding techniques, and other stuff like fin fillets, different glues, etc. Maybe even some fiber wrapping on cheaper projects. Lots of stuff that will help me make my L2 not only more complex (with electronics) but also look a heck of a lot nicer.
I suppose the door could swing both ways on that one. Personal taste is a very important factor in this discussion I think, as well as goals for rocketry.
I love the way you captured this feeling of progression so well, as it is a satisfying and gratifying way to do things.

HHaase

Well-Known Member
A common theme I see new HPR fliers struggle with is how the higher velocities, mass, and g-forces start changing the performance of recovery gear. We just had a few L1 Cert flights for a local College team. While their build quality was excellent all around, and the flights generally went well, there were some areas that I think would have been more successful with some MPR experience. They all struggled with delay timing and chute packing. It cost one of them a failed bulkhead and a non-certification, but the rocket was at least easily repairable. The lack of flight experience at higher velocities showed. I also had to send a couple back to work on their friction fit nose cones before I let them fly.

There are so many things that are just different enough that I definitely recommend working through MPR before going HPR. With a 24/29mm fleet you can incrementally learn to deal with nylon chutes, epoxies, loading/assembling composite motors, kevlar shock cords, rail guides, thrust rings, motor retainers, shear pins, different methods of chute protection, cutting delays, and all those little things that are optional with an E-F-G motors.

-Hans

JRL303

Well-Known Member
Personally I think the progression thru ‘mid power’ helps you think more about safety and stability issues. When I was building and flying low power I never gave thought to CG and CP, or even recovery systems. I just built the kit and had a blast.

As the rockets get bigger and faster there is much more potential for something to go wrong. Mid power gives you a chance to build some rockets where you really need to check stability before put that ‘big’ G reload motor in it.
This.

Fly lots of E18, F24 and G64's, Your H128 L1 will be no problem.

58pan

Well-Known Member
TRF Supporter
Saw a guy build a 4 inch DX3 with so much epoxy in the motor mount that anything bigger than a H was unstable.
He could have added nose weight except he also glued the nose cone and payload bay all together.
He had a lot of RC plane experience but had just gotten into rocketry that year.
This guy is NOT dumb and he builds beautiful rockets, but experience DOES make a difference.

woferry

Well-Known Member
The simple fact is that I went straight from D to H without ever flying anything in between [...] In fact I might not have flown a G until after I was L3. That doesn’t say anything good or bad; I was just enjoying HPR.
Same basic track for me, with a big time-delta in-between also. From flying model rockets as a kid (may not have even made it to a D, don't recall), to ~25 years of no flying at all, to my successful L1 cert flight (H148R). I didn't fly a G motor until after I had my L2 (not an L3 yet), and G's have been 2 of my 95 motors flown and they were just smaller motors in a HPR rocket (38mm RW Go Devil) to stay low on cloudy days since any H would have been in the clouds but I still wanted to fly something. It helped to have some good mentors to work with, and a really easy L1 kit to build (GLR T-Bolt, 38mm MD with the Acme fin can).

Though my dad surely helped me build some of the model rockets as a kid (or at least watched), his first flight ever was his successful L1, building a T-Bolt also.

Buckeye

Well-Known Member
That said, it’s not a requirement. I went to a multi-day club launch about 6 years ago where a group of 25 or so college students were there to cert. They had a mentor who had guided them through their builds and was there to advise on their flights and sign off their certs.

They had all built exactly the same model of simple L2 capable fiberglass rocket. On the first day, they all flew their L1 flights on the same type of DMS I motor. They did their L2 written test. And on the second day, they all flew their L2 flights on the same kind of DMS J motor.

I’m sure for a lot of them, those were their first flights ever. So after building one rocket with supervision and doing 2 motor-deploy flights on single-use motors, most of them left with an L2 cert and the legal right to buy and fly motors up to L impulse.
I think this is dumb and the "mentor" should have his head examined. Not only are these newly-minted L2's with all of two flights under their belts able to fly L impulse, but they qualify to RSO, LCO, and can sign off on certs of other newbies. This assumes that they even bother to attend another launch, but most never do, thankfully. They got the "experience" of rocketry and moved on to the next thing.

Off Grid Gecko

Well-Known Member
I think this is dumb and the "mentor" should have his head examined. Not only are these newly-minted L2's with all of two flights under their belts able to fly L impulse, but they qualify to RSO, LCO, and can sign off on certs of other newbies. This assumes that they even bother to attend another launch, but most never do, thankfully. They got the "experience" of rocketry and moved on to the next thing.
While I respect your opinion, the RSO at the launch cleared the rockets, which I think is the main thing. No telling how much probing he/she did into their construction techniques and assessing their flight readiness. Same with the mentor. I don't know his history either.
What I do know is that in a classroom or mentor environment, much can be learned quickly, and sometimes better than going it alone with some F motors in a field (i.e. outside a club launch environment). I was cleared to work with (handle, inspect, transport, etc) nuclear sources by the NRC after a couple weeks of training.
Calling somebody "dumb" seems a bit rash of an assessment based on what was presented.

ThirstyBarbarian

Well-Known Member
TRF Supporter
I think this is dumb and the "mentor" should have his head examined. Not only are these newly-minted L2's with all of two flights under their belts able to fly L impulse, but they qualify to RSO, LCO, and can sign off on certs of other newbies. This assumes that they even bother to attend another launch, but most never do, thankfully. They got the "experience" of rocketry and moved on to the next thing.
I didn’t think it was a great idea. But I don’t really know what the context of the thing was. They all looked like college students, so I don’t know if the certs were the end goal, or maybe they were working on a separate college project and wanted everyone on the project to be certified.

OKTurbo

Well-Known Member
I don’t think he meant that the rockets weren’t checked out by the RSO...what he said was that as new Level 2 certified flyers they are able to hold the position of RSO at a launch....and just two flights may not have given them enough experience to properly fill that role.

Off Grid Gecko

Well-Known Member
I don’t think he meant that the rockets weren’t checked out by the RSO...what he said was that as new Level 2 certified flyers they are able to hold the position of RSO at a launch....and just two flights may not have given them enough experience to properly fill that role.
Agreed on that front. I would say that an RSO should also have experience attending several launches as well. Not just building but seeing many many flights and have a good understanding of what works and what doesn't. But I also don't know how RSOs are selected for launches. I would assume that would be a decision made by each club, and internally they would regulate it in such a way that these kids wouldn't be recommended for that job.
Despite what I just said, I don't want to discourage Buckeye's opinion, everyone has a right to speak their mind. My main complaint with the post was the childing nature of it. I could be wrong and there could be a bunch of mindless teenagers out there (maybe they were younger than they appeared) who are planning to jump straight to an L3 build once they can find a TAP. Imagine that, an L3 with 3 flights total! That might make me a tad nervous, especially if they were below the legal drinking age.

Nytrunner

Pop lugs, not drugs
Calling somebody "dumb" seems a bit rash of an assessment based on what was presented.
Yeah, that happens semi-regularly in this hobby. Fortunately its not the majority behaviour

what he said was that as new Level 2 certified flyers they are able to hold the position of RSO at a launch....and just two flights may not have given them enough experience to properly fill that role.
But I also don't know how RSOs are selected for launches. I would assume that would be a decision made by each club, and internally they would regulate it in such a way that these kids wouldn't be recommended for that job.
I dont think anyone can just go up during a launch or club meeting and say "I'm L2 now, so I get to be RSO next launch". Every club or national event I've been at has had regularly active, well known, and experienced members serve as RSO. I like to think of the L2 qualification being a Bare Minimum.

Heck, as an L1 I got to assist the RSO at one of our regional launches handling the low and mid power stuff. It was good experience

Imagine that, an L3 with 3 flights total! That might make me a tad nervous, especially if they were below the legal drinking age.
Depends on the flier. There are smart capable individuals who I wouldn't bat an eye at taking that path. Their circumstances or budget may restrict their flight volume, but doesn't invalidate their capability and successful results (even if they have a 'small' number of flights)
Then there are others who've flown for over a decade and still dart or shred every other flight. I'd hesitate to have them be RSO for a boyscout launch

Well-Known Member
TRF Supporter
Not only are these newly-minted L2's with all of two flights under their belts able to fly L impulse, but they qualify to RSO, LCO, and can sign off on certs of other newbies.
planning to jump straight to an L3 build once they can find a TAP. Imagine that, an L3 with 3 flights total! That might make me a tad nervous
I think some of us here are taking certification way too seriously.

A cert doesn't mean anything other than the fact that a person had followed kit instructions assembling a rocket, paid money for a motor, launched it, and someone witnessed him getting the thing back in one piece.
Nothing more, nothing less.

I am pretty sure Elon Musk is not L3 certified, but he seams to be doing OK in the rocketry field.
Sadly, for him (I'm sure), he does not qualify for an RSO/ LCO position in our hobby.

boatgeek

Well-Known Member
...I could be wrong and there could be a bunch of mindless teenagers out there (maybe they were younger than they appeared) who are planning to jump straight to an L3 build once they can find a TAP. Imagine that, an L3 with 3 flights total! That might make me a tad nervous, especially if they were below the legal drinking age.
I suspect that most TAPs and L3CC members would tell that person to go get more L2 experience before attempting L3. It's possible that they would be able to shop for a TAP successfully, but I think word would get around pretty quickly.

Zman1961

Active Member
This is a very interseting thread. My BAR status began about 4 years ago with MPR. I was fortunate to have joined my local TRA chapter at the same time. The discussions I had with the other members (who are always more then generous with their help) had me building my MPRs with the HPR techniques dicscussed above from the beginning, and I learned a lot very quickly. I was building the Estes PS II's, which are on the moderate to large end of the MPR "category," and were fairly robust kits. I added a couple of things for my first HPR for my L1, like internal fin fillets, precise balancing for good CG/stability (not much of a concern with the Estes MPRs), etc. Then I did use the Aerotech DMS motors, and it went very well. The main thing is to take your time, learn as you go to promote safety and success, get to know a lot of great people, and mostly to have fun.

o1d_dude

'I battle gravity'
FWIW, I started out building and launching Estes kit LPR’s at the local club launches. Then I moved up to some small scratch built MPR’s. Captain Low and Slow suggested I attend a LUNAR launch at Snow Ranch...and that changed everything.

My MPR’s started going higher and faster to the point the local club started reminding me of the waiver at the pre-launch meeting. A 12” long BT60 tube fin rocket on an E30 does in fact scoot and an 18” long 54mm tube fin on a G80 simply vanishes when the launch button is pressed.

I then moved up to 3” diameter tubing and certed Level 1 on a scratch built tube fin with motor deploy. The following year I converted the L1 bird to a dual deploy and flew it a few times in that configuration. It always drew comments back then.

My L2 bird was a kit rocket...a Polecat Aerospace Goblin 5.5” which I have flown ~only~ with motor deploy and Jolly Logic Chute Release in spite of having a nose cone av bay for dual deploy with a cable cutter for the main. The L3 who did my cert said “You fly dual deploy all the time, what’s up with this?” Told him I spent a year launch testing various chutes and harness configurations to get a high level of reliability from the JCLR. He shrugged and gave his blessing.

After a season of launching the Goblin on BIG I-motors, the L2 flight on a baby J was a bit of letdown...and I haven’t flown the Goblin since. This season we’ve only had two HPR launches since last fall and two local LPR/MPR launches.

By following the experience trajectory, I learned a lot along the way and feel the trip was worth the effort.

Joshua F Thomas

Well-Known Member
I don't know about other people, but before I spend $100+ on a quality HPR kit and$30+ per motor, I want to be sure my skills are good enough for the bird to fly well. Plus it seems like a lot of HPRs use fiberglass or dual-deploy. I'll want to gain experience with those techniques on smaller birds before going up to the really expensive stuff.

Besides which, I can only launch them at my club launches where we have a waiver, and maybe you just want to fly some birds at your local park?

[Yes, I know reusable takes prices down, but when you start out your outlay is larger.]

grouch

Well-Known Member
Midpower is by no means a prerequisite but why skip it? It's a heck of a lot of fun in it's own right. I still fly more G's than any other motor class combined X3 just because they are fun and I tend to like rockets on the smaller side of the scale. You can get some crazy performance out of a small well build rocket on a large G.