Class 1 launch rules for MPR?

[Saint_Tiki]

Hello. I'm having trouble cracking the code on mid-power and class 1 and where the line is drawn. Looking for some clarification. 1127 is a rough read...

Can I launch a G126 motor at a class 1 launch if I am high-power certified?
Can I launch an H-class motor at a class 1 launch if the propellant weight is less than 125g?
Can I launch a G-class motor at a class 1 launch if the propellant weight is more than 62.5g?

Until I started digging, I thought the answer to some of these might have been yes, but now I'm thinking they are all a "no".

Mostly what I'm getting at is where is the overlap between FAA definitions and 1127? Or is it that if any criteria is busted then it falls under the most conservative definition?

 

[ThirstyBarbarian]

If you are attending a club launch, then you need to check with the club about the rules for the launch. Some clubs may just use the FAA definition for Class 1 to limit the kinds of flights allowed — they are only concerned about whether they need to get an FAA waiver. While other clubs may also limit the kinds of motors allowed — they don’t want to be checking high-power certifications or making judgements about the edge-case motors, or they may have landowner or other restrictions.

Most clubs I’ve flown with have followed the stricter set of rules for launches that are not their HPR launches. They don’t want high power by any definition, including both FAA and NFPA. So no Class 2 rockets that would require an FAA waiver — rockets must be under 1,500 grams, and propellant must be under 125grams. And no high-power motors that would require a high-power certification — average thrust must be 80N or under, total impulse 160Ns or less, no sparkies.

I think it would be great for more clubs to have Class 1 launches and allow the high power motors under 125 grams propellant, because the club would not need a waiver, but could still allow some Level 1 HPR flights, including cert flights with rockets under 1,500 grams and H motors under 125 grams, like the H135, H115, etc. It would also allow high-thrust F and G motors, like F100 or G125. And it would allow sparkies, like G75 and G72. Unfortunately that’s kind of rare.

If you are not planning to fly with a club and just want to know the rules for a Class 1 flight, like maybe you want to fly on your own property but don’t want to get a waiver, then only the FAA rules apply, not the NFPA. If that’s the case, here are the answers to your questions:

Can I launch a G126 motor at a class 1 launch if I am high-power certified? Yes. You can fly motors over 80N average thrust if you are certified, and it will not affect whether the rocket is Class 1 or not. It might not be allowed at a club launch, but it does not affect whether a waiver is required.

Can I launch an H-class motor at a class 1 launch if the propellant weight is less than 125g? Yes. If you are certified or attempting a certification flight, you can fly an H motor under 125 grams propellant, and it is still a Class 1 flight. Again, it might not be allowed at club launches, but it would not require an FAA waiver.

Can I launch a G-class motor at a class 1 launch if the propellant weight is more than 62.5g? Yes, I think so. I don’t remember what the 62.5 gram limit pertains to, but I think it has to do with mailing or shipping motors? I’m pretty certain this does not have anything to do with Class 1.

I hope this answers your questions. Are you planning to go up to the edge of Class 1?

 

[Art Upton]

62.5 grams was a past ATF issue and certain shipping issues, sometimes.

Under FAR 101
Any total propellent weight under 125g is still Class One.

Clubs will have their own rules on what they let fly from what pads and distance.

 

[samb]

Ditto what Thirsty and Art said, all of your hypotheticals are right at the edge of FAA Class 1. Club rules rule, usually to keep the neighbors happy. My go to reference is the lovely graph in this document.

 

[ThirstyBarbarian]

62.5 grams was a past ATF issue and certain shipping issues, sometimes.

Under FAR 101
Any total propellent weight under 125g is still Class One.

Clubs will have their own rules on what they let fly from what pads and distance.

Good point on pads and distance. That’s another reason some clubs don’t allow the H motors under 125 grams at unwaivered launches — they literally are “not set up for it.” An H motor needs a 100’ safety distance from the flight line, and most unwaivered launches have the furthest pads at 30 or 40 feet or whatever the G motor setback is.

 

[ThirstyBarbarian]

Ditto what Thirsty and Art said, all of your hypotheticals are right at the edge of FAA Class 1. Club rules rule, usually to keep the neighbors happy. My go to reference is the lovely graph in this document.
View attachment 585541

That’s a great graphic and one I refer to as well.

You are right about keeping the neighbors happy, also keeping the field owner, insurance company, local fire department, and police happy. There are a lot of factors. My experience is that almost everything flows from the field requirements. So if it’s below a certain size, you get altitude restrictions that have nothing to do with the FAA and are about not flying rockets out of the field, and along with altitude restrictions, sometimes come motor restrictions, just to keep the likelihood for breaking the ceiling low. I’ve been to launches where the motor limits are E or F motors.

You always have to check with the club about club rules for their field. And on that note, nobody appreciates a “rocket lawyer” arguing regulations at a launch, trying to convince the club to bend a club rule because it’s not based on FAA or NFPA regulations. I’ve seen those kinds or arguments around motors like G125 or sparky G motors. It’s a great way to be invited to leave and never come back.

 

[rcktnut]

HPR class motors allowed under class 1 launches still require all HPR rules in force. The only difference in class 1 is no waiver required, all other HPR rules, codes need to be followed.

 

[Art Upton]

You always have to check with the club about club rules for their field. And on that note, nobody appreciates a “rocket lawyer” arguing regulations at a launch, trying to convince the club to bend a club rule because it’s not based on FAA or NFPA regulations. I’ve seen those kinds or arguments around motors like G125 or sparky G motors. It’s a great way to be invited to leave and never come back.

Yes, never be that Dude or Dudette

 

[Art Upton]

HPR class motors allowed under class 1 launches still require all HPR rules in force. The only difference in class 1 is no waiver required, all other HPR rules, codes need to be followed.

Well yea, they are an HPR motor

 

[Saint_Tiki]

If you are attending a club launch, then you need to check with the club about the rules for the launch. Some clubs may just use the FAA definition for Class 1 to limit the kinds of flights allowed — they are only concerned about whether they need to get an FAA waiver. While other clubs may also limit the kinds of motors allowed — they don’t want to be checking high-power certifications or making judgements about the edge-case motors, or they may have landowner or other restrictions.

Most clubs I’ve flown with have followed the stricter set of rules for launches that are not their HPR launches. They don’t want high power by any definition, including both FAA and NFPA. So no Class 2 rockets that would require an FAA waiver — rockets must be under 1,500 grams, and propellant must be under 125grams. And no high-power motors that would require a high-power certification — average thrust must be 80N or under, total impulse 160Ns or less, no sparkies.

I think it would be great for more clubs to have Class 1 launches and allow the high power motors under 125 grams propellant, because the club would not need a waiver, but could still allow some Level 1 HPR flights, including cert flights with rockets under 1,500 grams and H motors under 125 grams, like the H135, H115, etc. It would also allow high-thrust F and G motors, like F100 or G125. And it would allow sparkies, like G75 and G72. Unfortunately that’s kind of rare.

If you are not planning to fly with a club and just want to know the rules for a Class 1 flight, like maybe you want to fly on your own property but don’t want to get a waiver, then only the FAA rules apply, not the NFPA. If that’s the case, here are the answers to your questions:

Can I launch a G126 motor at a class 1 launch if I am high-power certified? Yes. You can fly motors over 80N average thrust if you are certified, and it will not affect whether the rocket is Class 1 or not. It might not be allowed at a club launch, but it does not affect whether a waiver is required.

Can I launch an H-class motor at a class 1 launch if the propellant weight is less than 125g? Yes. If you are certified or attempting a certification flight, you can fly an H motor under 125 grams propellant, and it is still a Class 1 flight. Again, it might not be allowed at club launches, but it would not require an FAA waiver.

Can I launch a G-class motor at a class 1 launch if the propellant weight is more than 62.5g? Yes, I think so. I don’t remember what the 62.5 gram limit pertains to, but I think it has to do with mailing or shipping motors? I’m pretty certain this does not have anything to do with Class 1.

I hope this answers your questions. Are you planning to go up to the edge of Class 1?

Awesome. This was great, thank you.

I’m L1 certified but have moved states and am looking at nearby clubs. There’s a mid power site nearby that launches monthly. Guess I’ll need to reach out and see what exactly they allow and don’t.

I’m working on a 2-stage mid power rocket. Being able to put a high thrust G motor in it could help a few things which is sort of what sent me down the rabbit hole.

 

[Saint_Tiki]

That’s a great graphic and one I refer to as well.

You are right about keeping the neighbors happy, also keeping the field owner, insurance company, local fire department, and police happy. There are a lot of factors. My experience is that almost everything flows from the field requirements. So if it’s below a certain size, you get altitude restrictions that have nothing to do with the FAA and are about not flying rockets out of the field, and along with altitude restrictions, sometimes come motor restrictions, just to keep the likelihood for breaking the ceiling low. I’ve been to launches where the motor limits are E or F motors.

You always have to check with the club about club rules for their field. And on that note, nobody appreciates a “rocket lawyer” arguing regulations at a launch, trying to convince the club to bend a club rule because it’s not based on FAA or NFPA regulations. I’ve seen those kinds or arguments around motors like G125 or sparky G motors. It’s a great way to be invited to leave and never come back.

Great advice, thank you. Just trying to educate myself mostly. I’ll be reaching out to the (new to me) nearby club to see what ruleset they have established for their mid power launches.

 

[ThirstyBarbarian]

Awesome. This was great, thank you.

I’m L1 certified but have moved states and am looking at nearby clubs. There’s a mid power site nearby that launches monthly. Guess I’ll need to reach out and see what exactly they allow and don’t.

I’m working on a 2-stage mid power rocket. Being able to put a high thrust G motor in it could help a few things which is sort of what sent me down the rabbit hole.

Sounds like a good plan. That’s what I would do.

I’ve run into the same situation before where a high-thrust G would be ideal, but it’s not allowed. If you search https://www.thrustcurve.org/, you might be able to find some motors with a good, strong initial thrust spike well over 80N, but still have a nominal average thrust under 80. That’s one way to get off the pad fast and straight but keep to the rules. You can use Thrustcurve to do an automatic search for motors that will get a rocket of a defined mass and diameter off the pad safely.

And if you still have trouble finding a motor, you might try increasing the rail length. Maybe check with the club if they have an 8- or 10-foot rail at their midpower launches or if you or someone else can provide one. I’ve done that when trying to fly the biggest possible Class 1 rocket at a midpower launch.

My project was to build a large rocket out of foam insulation board. It weighed in at just under the 1,500 gram limit fully loaded. I flew it on a CTI G54, which has a good thrust curve with a nice initial high thrust that tapers off. And I flew it off a 10-foot rail provided by a friend.

 

[Saint_Tiki]

Sounds like a good plan. That’s what I would do.

I’ve run into the same situation before where a high-thrust G would be ideal, but it’s not allowed. If you search https://www.thrustcurve.org/, you might be able to find some motors with a good, strong initial thrust spike well over 80N, but still have a nominal average thrust under 80. That’s one way to get off the pad fast and straight but keep to the rules. You can use Thrustcurve to do an automatic search for motors that will get a rocket of a defined mass and diameter off the pad safely.

And if you still have trouble finding a motor, you might try increasing the rail length. Maybe check with the club if they have an 8- or 10-foot rail at their midpower launches or if you or someone else can provide one. I’ve done that when trying to fly the biggest possible Class 1 rocket at a midpower launch.

My project was to build a large rocket out of foam insulation board. It weighed in at just under the 1,500 gram limit fully loaded. I flew it on a CTI G54, which has a good thrust curve with a nice initial high thrust that tapers off. And I flew it off a 10-foot rail provided by a friend.

I'll ask about the longer rail. That's a good call and would open up some more options.

Currently planning on using the aerotech hobbyline reload G76 for the booster. It has a very favorable thrust curve peaking at about 150N initially and tapering. It absolutely RIPS off the pad and they're pretty cheap. I've used it to launch my just-over-3lb rocket before with plenty of off-the-rail velocity. And I once used it on a ~1lb rocket which I think briefly touched the speed of light before it completely disappeared into the air.

 

[ThirstyBarbarian]

I'll ask about the longer rail. That's a good call and would open up some more options.

Currently planning on using the aerotech hobbyline reload G76 for the booster. It has a very favorable thrust curve peaking at about 150N initially and tapering. It absolutely RIPS off the pad and they're pretty cheap. I've used it to launch my just-over-3lb rocket before with plenty of off-the-rail velocity. And I once used it on a ~1lb rocket which I think briefly touched the speed of light before it completely disappeared into the air.

That sounds like a great motor choice!

 

[jmasterj]

I'll ask about the longer rail. That's a good call and would open up some more options.

Currently planning on using the aerotech hobbyline reload G76 for the booster. It has a very favorable thrust curve peaking at about 150N initially and tapering. It absolutely RIPS off the pad and they're pretty cheap. I've used it to launch my just-over-3lb rocket before with plenty of off-the-rail velocity. And I once used it on a ~1lb rocket which I think briefly touched the speed of light before it completely disappeared into the air.

Yep, that's the motor I would choose. Biggest initial thrust spike of any non-HPR motor, I believe.

 

[rcktnut]

Awesome. This was great, thank you.

I’m L1 certified but have moved states and am looking at nearby clubs. There’s a mid power site nearby that launches monthly. Guess I’ll need to reach out and see what exactly they allow and don’t.

I’m working on a 2-stage mid power rocket. Being able to put a high thrust G motor in it could help a few things which is sort of what sent me down the rabbit hole.

Question: G76 in booster, what are you staging that to?

 

[Saint_Tiki]

Question: G76 in booster, what are you staging that to?

Probably a CTI F32, that’s what I have in mind currently. Or maybe a F30 longburn. Goal is to make a successful 2-stage build that I can fly on mid power just for the heck of it. Would only be going to <2k’. Can also fly it on high power or add tracking if I really want to send it after I have some more experience with it.

 

[waltr]

My local club (PARA 520) is NAR 'model' rockets only. Our Range rules are:

RESTRICTIONS:

High power rockets have a 1500 foot launch pad distance requirement in the safety code that we are unable to meet. We are bound to the 160 to 320 Newton-second total impulse limit. Rockets can not weigh more that 53 ounces (3lbs, 5oz) with the motor(s) installed. They can not contain more than 125 grams (4.4oz) of rocket propellant. A single motor can not have more than 80 Newtons of Average Thrust. This limits us to a G80 motor. We can launch a rocket with a 2G cluster or 4F cluster as long as it does not violate the above restrictions.

I also fly 2-stage composite with air start. To obtain enough speed off the rail to ensure minimal wind cocking I bought a 6 foot 1010 rail and made connectors to extend the club's 6 foot rail.
At local club typically fly an AT G74 to an AT D15 or CTI E22. This is to keep altitude lower due to smaller open fields and lots of surrounding trees.