Certification motors

[skaffgeorge2]

Hello, just a fairly simple question, What's the lowest power motor you can use to certify Level One with?I haven't even begun to consider attempting it yet, for two simple reasons, no place to fly and a low fixed income.The closest area to me is over three hours away and I don't drive so there's that also.I've been in this for well over fifty years and have never flown anything over a D motor.High power rocketry is just far too expensive for me.So here I am stuck here with my little bottle rockets with no place to fly them.There are two clubs located south of me but the lack of transportation makes it virtually impossible for me to get there, I don't know any other flyers in my area so that makes it even more difficult.So if anyone has a workable suggestion or suggestions they can offer I would be greatly appreciated.Oh, I also forgot to mention,I live in NorthEastern Pennsylvania.Nothing but trees and hills, there's no open land left here, and that's why I haven't flown in over 40 years.What's a poor soul like me supposed to do?I considered giving it up but that's not an option any longer.I just don't see a way out of this conundrum, does anyone else?C'mon somebody, throw me a lifeline here, ok?

 

[Velocity Aerospace]

From my experience, the aerotech H-45W-P or the H-100W-14A would be the lowest power. The H-45 has a longer burn time at 6 seconds, but it has the lowest thrust. There may be some other options with Ceccaroni or even with AeroTech. I would recommend looking on apogee's website. They have great comparison tables for stuff like this. I'm sorry to hear that you have such a hard time getting out, and I wish you the best of luck

 

[skaffgeorge2]

From my experience, the aerotech H-45W-P or the H-100W-14A would be the lowest power. The H-45 has a longer burn time at 6 seconds, but it has the lowest thrust. There may be some other options with Ceccaroni or even with AeroTech. I would recommend looking on apogee's website. They have great comparison tables for stuff like this. I'm sorry to hear that you have such a hard time getting out, and I wish you the best of luck

Thanks for the input.Just for the sake of it, what altitudes would we be talking about with the H45 and H100?I I were to attempt it it would have to be a very low and slow flight, s I'm not sure what vehicle I would use but it would have to be as simple a design as possible, LOC kits are known for their reliability and simplicity.Would you have an opinion as to what vehicle I could use? I would appreciate your feed back on this.

 

[tsmith1315]

H45 has a low average impulse, but a long burn time. It's 100% H at 320 N-s, that is to say: just one more N-s and it would be an I motor. H motors are from 160-320 N-s total impulse. The smallest L1 motors are going to be near the 160N-s range, and you have to look at the motor data to find the total impulse.

In Aerotech products, the H238T and H165R are baby-H reloads for 29/180 hardware that are just over the H motor threshold. In 29mm single use, the H115DM is about the same total impulse as those two. These are all in the 165-170N-s range. A typical lightweight 4" LOC rocket with nothing fancy will probably do 1000-1500' on these.

In CTI, there are a few 29mm 3 and 4 grain motors that are just over the 160g limit:
http://pro38.com/products/pro29/motor.php

 

[boatgeek]

The CTI H87 and H90 are great certification motors. Not quite as much thrust so they're a little easier on the rocket, but enough to get off the pad easily. They also are just barely H motors so the rocket doesn't go too high. Since they're under 125g of propellant, you don't even need an FAA waiver to fly them.

Thanks for the input.Just for the sake of it, what altitudes would we be talking about with the H45 and H100?I I were to attempt it it would have to be a very low and slow flight, s I'm not sure what vehicle I would use but it would have to be as simple a design as possible, LOC kits are known for their reliability and simplicity.Would you have an opinion as to what vehicle I could use? I would appreciate your feed back on this.

How high depends on the rocket. They'll go 3-4 thousand feet easily on a light minimum diameter rocket, or less than a thousand on a heavier 4" rocket.

 

[Sooner Boomer]

Once you achieve your L1, how often do you think you'll fly? Do you think you'll build/fly rockets equivalent to your cert rocket? Do you think you'll go on to higher levels of certification?

There are two reasons for my asking these questions. If you're only going to fly the cert flight, then fly high power only rarely, then a single-use motor might be the best way for you to go. If, however, you think you'll fly often, or even several times a year, then using an RMS (Reloadable Motor System) might be better. If you're hoping to advance in level of high power, an RMS would bear close thought.

The second half is cost. RMS cases are somewhat expensive at first, but the more you fly, the cost is spread out over the flights. As long as you don't lose or damage the case/closures, they should last forever. Another aspect of cost is buying the reload/motor, and paying for shipping. There are several loads that do not require the expensive haz-mat shipping. Attached is a list of non-haz-mat motors/reloads.

If you're thinking of flying bigger and more powerful rockets/motors, something to consider is the Aerotech RAS (Reload Adapter Sysyem), a special top closure that holds the delay grain and ejection charge, a closure ring to hold it in place, and a set of spacers that go inside the motor case that allow you to "down-load" the reload a particular motor uses. You should be able to find sets that have two motor cases with a set of closures and spacers that allow you to fly almost any reload in that motor diameter. Attached is a list for 29 and 38mm loads.

Last - if you think you *might* want to go bigger sometime in the future, consider this - you can adapt a smaller motor to fit into a latger motor mount, but there's no way to put a bigger diameter in a small tube.

 

[skaffgeorge2]

Once you achieve your L1, how often do you think you'll fly? Do you think you'll build/fly rockets equivalent to your cert rocket? Do you think you'll go on to higher levels of certification?

There are two reasons for my asking these questions. If you're only going to fly the cert flight, then fly high power only rarely, then a single-use motor might be the best way for you to go. If, however, you think you'll fly often, or even several times a year, then using an RMS (Reloadable Motor System) might be better. If you're hoping to advance in level of high power, an RMS would bear close thought.

The second half is cost. RMS cases are somewhat expensive at first, but the more you fly, the cost is spread out over the flights. As long as you don't lose or damage the case/closures, they should last forever. Another aspect of cost is buying the reload/motor, and paying for shipping. There are several loads that do not require the expensive haz-mat shipping. Attached is a list of non-haz-mat motors/reloads.

If you're thinking of flying bigger and more powerful rockets/motors, something to consider is the Aerotech RAS (Reload Adapter Sysyem), a special top closure that holds the delay grain and ejection charge, a closure ring to hold it in place, and a set of spacers that go inside the motor case that allow you to "down-load" the reload a particular motor uses. You should be able to find sets that have two motor cases with a set of closures and spacers that allow you to fly almost any reload in that motor diameter. Attached is a list for 29 and 38mm loads.

Last - if you think you *might* want to go bigger sometime in the future, consider this - you can adapt a smaller motor to fit into a latger motor mount, but there's no way to put a bigger diameter in a small tube.

That's somewhat helpful.But it's all strictly conjecture from me at this point

Once you achieve your L1, how often do you think you'll fly? Do you think you'll build/fly rockets equivalent to your cert rocket? Do you think you'll go on to higher levels of certification?

There are two reasons for my asking these questions. If you're only going to fly the cert flight, then fly high power only rarely, then a single-use motor might be the best way for you to go. If, however, you think you'll fly often, or even several times a year, then using an RMS (Reloadable Motor System) might be better. If you're hoping to advance in level of high power, an RMS would bear close thought.

The second half is cost. RMS cases are somewhat expensive at first, but the more you fly, the cost is spread out over the flights. As long as you don't lose or damage the case/closures, they should last forever. Another aspect of cost is buying the reload/motor, and paying for shipping. There are several loads that do not require the expensive haz-mat shipping. Attached is a list of non-haz-mat motors/reloads.

If you're thinking of flying bigger and more powerful rockets/motors, something to consider is the Aerotech RAS (Reload Adapter Sysyem), a special top closure that holds the delay grain and ejection charge, a closure ring to hold it in place, and a set of spacers that go inside the motor case that allow you to "down-load" the reload a particular motor uses. You should be able to find sets that have two motor cases with a set of closures and spacers that allow you to fly almost any reload in that motor diameter. Attached is a list for 29 and 38mm loads.

Last - if you think you *might* want to go bigger sometime in the future, consider this - you can adapt a smaller motor to fit into a latger motor mount, but there's no way to put a bigger diameter in a small tube.

Interesting, however it's probably just academic at this point because I really don't know if I'll be able to do it or not, my budget ceiling is so low that I doubt I can realistically afford it.I know for certain I wouldn't be able to go any higher than that so no Level Two and Level 3 is definitely out of the question.I was basically just looking for ideas should the situation present itself.I guess I just have to be content with what I have.Most of the kits I have in my build pile are decades old classic kits along with some newer ones,I searched a very long time to find a Centuri Nike Smoke and finally found one one line.Not likely that things will change for me anytime soon , but if they do,who knows?Time will tell

 

[rharshberger]

Rocketry is not a cheap hobby...anyone that tells you otherwise is a motor vendor....

However, the lower end of HPR can be enjoyed with a little planning and willingness to save a bit and "splurge" at the Black Friday motor sales when you get the most bang for your buck.

Enjoy the hobby at whatever level you choose, you may even decide to go for L2 eventually, but that is a personal decision and I know many fliers who are and plan only to be L1.

 

[boatgeek]

If your club has a local Aerotech vendor, a DMS motor can be had for ~$45 and an RMS for ~$30. If you have a rocket with a 29mm motor mount, most likely either of these will work for you. The trick is getting to the launch site (can you get a ride in exchange for gas or food?) and for the RMS, borrowing a casing. Most of the time, you can borrow a casing under the understanding that if you break it, you buy a new one for the lender. If there's a vendor on site who would have the motors in stock, you don't even need to pay shipping or hazmat fees.

As Rich says, it's an expensive hobby, but limited trips into HPR can be fairly reasonable.

 

[smstachwick]

All certification flights must be made on H or I motors. At the very bottom of the H total impulse class are the Contrail H222 and H300 hybrids, both with 161 N-sec of total impulse.

However, these are probably not good starting points. Hybrids come with a bit of a learning curve and some expensive GSE, although the latter can sometimes be mitigated by using gear that other hybrid fliers make available.

At 163.3 N-sec is the Cesaroni H133. The casing, Cesaroni’s Pro29 3G, has a two G loads that can be flown certification-free, plug a few HPR G and H loads. It can also accept spacers to fly loads designed for the Pro29 2G and Pro29 1G cases. Cesaroni appears to be having logistical difficulties at this time though, especially on the warranty side. While this might be a good option for regular MPR/HPR flights, you’re pretty much on your own if something goes wrong.

At 165 N-sec is the AeroTech H165R. The RMS 29/180 casing has options for other G and H reloads as well. These motors require assembly and the up-front cost of acquiring the hardware, but can be good investments if you do a lot of flying with them.

At 172 N-sec is the AeroTech H115DM, a 29mm preassembled single-use motor. It requires Hazmat shipping but you might be able to get around this with an on-site vendor, or you can pool shipping costs with other members looking to save on hazmat. This one would probably be your best bet for one or two certification flights, unless for whatever reason your flying site is not allowing sparky propellants.

All of this info is available on Thrustcurve.org.

 

[JohnCoker]

You might get a bigger picture by browsing motors in ThrustCurve.org:
https://www.thrustcurve.org/motors/browser.html?1class=H

 

[Hobie1dog]

The CTI H87 and H90 are great certification motors. Not quite as much thrust so they're a little easier on the rocket, but enough to get off the pad easily. They also are just barely H motors so the rocket doesn't go too high. Since they're under 125g of propellant, you don't even need an FAA waiver to fly them.

+1

 

[Steve Shannon]

@skaffgeorge2,
Although high power rocketry is great fun, you usually don’t need to become certified to fly with high power clubs. Most clubs welcome model rocket flyers. Don’t feel like you have to get certified to fit in. Contact a local club. Many of our members carpool and you might be able to catch a ride. Come and launch the rockets you have. Walk around and visit. Fly some E, F, and G motors if you want. Then, if you really want to certify for your own enjoyment you might even find that some of the senior flyers can advise you more helpfully based on your particular circumstances.

 

[prfesser]

If you haven't already done so, I would strongly suggest downloading OpenRocket---it's free, it's fun, and it's a great learning tool. You can find files for kits here (change to other manufacturers as desired), or design your own rockets. With OR you can run sims with various motors to determine expected altitude, appropriate delay times, etc. It will enable you to make a more objective choice of rocket and motor.

Increasing the diameter of the rocket is generally more effective at reducing altitude than adding weight. For example, my 3.1" diameter WAC Corporal will hit around 2300 feet on an H123. Scaling it up to 4" diameter but with the same weight reduces the altitude by 400 feet.

You'll have to go to a TRA or NAR launch (depending on which one you join) to certify. It's possible to design a rocket and use a motor that does not require an FAA waiver...but you need a prefect or a certified NAR member to sign your cert regardless. As you can't drive, I don't know how to solve that one...though you might be able to find a fellow member of your org who lives reasonably nearby and is willing to drive you to a launch.

Good luck!
Terry