Apogee Zephyr as Class 1 flyer?

[Mopo]

Has anyone been able to build a Zephyr to fly as class1, under 3.3lb? I'd like to be able to fly it at my local club launch to test and then also use it for L1.

I have seen pics of people flying LOC 4"goblin at my local club launch and see others on forum have been able to build this to stay under the limit so I will use it as my reference. It's the largest rocket I see flown there and I have been told it is basically the upper limit of what can be flown there, material wise (plastic cone / paper bt / wood fins) and power wise.

Goblin dry weight seems to be around 40-42oz vs the Zephy's is listed at 44oz.
The Zephyr comes with 2 18" booster sections and coupler, I was thinking of a shortened Zephyr with a single booster section bringing OAL to approx 38", same as the Goblin and reducing weight at same time.
Goblin has 4 fins vs the Zephyr's 3 but seem bigger.
Seems to sim out OK in OR but given the tight margin for error, was wondering if anyone had actually been able to do it.
I could just get the goblin since I know that's possible but I slightly prefer the aesthetics of the Zephyr, especially a shortened version.


thanks all!

 

[Adam3836]

Can you test it on some high thrust G motors ?
I no people who have tested there zephyr on G motors prior to L1 flights .

 

[rharshberger]

Has anyone been able to build a Zephyr to fly as class1, under 3.3lb? I'd like to be able to fly it at my local club launch to test and then also use it for L1.

I have seen pics of people flying LOC 4"goblin at my local club launch and see others on forum have been able to build this to stay under the limit so I will use it as my reference. It's the largest rocket I see flown there and I have been told it is basically the upper limit of what can be flown there, material wise (plastic cone / paper bt / wood fins) and power wise.

Goblin dry weight seems to be around 40-42oz vs the Zephy's is listed at 44oz.
The Zephyr comes with 2 18" booster sections and coupler, I was thinking of a shortened Zephyr with a single booster section bringing OAL to approx 38", same as the Goblin and reducing weight at same time.
Goblin has 4 fins vs the Zephyr's 3 but seem bigger.
Seems to sim out OK in OR but given the tight margin for error, was wondering if anyone had actually been able to do it.
I could just get the goblin since I know that's possible but I slightly prefer the aesthetics of the Zephyr, especially a shortened version.


thanks all!

Building light is your friend here, wood glue, very small fillets, thin mill chutes, motor deploy....

 

[Mopo]

Can you test it on some high thrust G motors ?
I no people who have tested there zephyr on G motors prior to L1 flights .

Yes, would like to be able to test on the AT LMS G-motors prior to the L1 or maybe even F67's for some cheap thrills if possible.

 

[TheTank]

I flew my original Zephyr on several G79Ws and G76G motors when I first built it. Didn't achieve any altitude records but it Flew fine. F67.... I wouldnt be that adventurous.

 

[waltr]

If you keep the weight under 1500gram (3.3#) with motor then a high thrust G (G76, G80) would be fine. Not sure if an F67 would have enough thrust for a safe speed off the rail.

Shortening the tubes would reduce weight and careful with glue etc as Rich stated.

Check this is the sim setting the rail length to the usable length, top of rail to the top button.
I did add a 4foot 1010 rail extension to our clubs 5.5foot rail to get higher speeds off the rail for heaver rockets or with lower thrust motors.

I chose the LOC 4" Goblin for L1 since I can fly it Class 1 of G's. Does about 500 feet of a G76 and needs a 4second delay. L1 flight on an H238 went to 956feet.

 

[ShadowSpire48]

The Goblin is the smarter choice for an L1 if you also want to fly it on G motors. I've seen one fly on an F67 but it was risky (did work though). Easy L1 on a small H to less than 1K and it's easier to carry around. Also I bet if you land that Zephyr just right and hard enough, there's a good chance of breaking those fin tips off that go below the body tube.

 

[Adam3836]

The Goblin is the smarter choice for an L1 if you also want to fly it on G motors. I've seen one fly on an F67 but it was risky (did work though). Easy L1 on a small H to less than 1K and it's easier to carry around. Also I bet if you land that Zephyr just right and hard enough, there's a good chance of breaking those fin tips off that go below the body tube.

Zephyr is a pretty robust rocket it’s got some thick fins… Iam sure In the right situation damage can be done but that goes for any rocket. Zephyr has been a really Popular pick over the last 2 years for a L1 rocket. I myself also picked the zephyr. Likes high thrust motors and with 29mm or 38mm you can definitely find a motor to keep it 1400ft or lower range

Goblins a classic also . Seems like two great picks

 

[waltr]

Yep, our local club has the Princeton U rocket club come out to do L1 cert flights. They always use the Zephyr with a 38mm motor to over 1000 feet. Just never checked sims to fly it as a Class 1 rocket.

 

[techrat]

To save weight, you could drill holes in the Zephyr's fins. This will increase drag, but you'd shave off at least an ounce in plywood. Another solution would be to cut out the center of each fin, leaving the plywood "outline" and then filling the center section with foamcore, cut to fit. Paper over each fin to hide the frankenstein solution, but it will definitely reduce the weight.

 

[Spitfire222]

Also I bet if you land that Zephyr just right and hard enough, there's a good chance of breaking those fin tips off that go below the body tube.

I had this concern when I was selecting a Level 1 rocket, but I was assured from other people on here that the Zephyr's fins are stout and can withstand quite a bit of punishment. I ended up going with a Zephyr myself, so I'll find out first hand!

 

[techrat]

I ended up going with a Zephyr myself, so I'll find out first hand!

It's a really good choice. FYI, Apogee has an entire series of youtube videos on building the Zephyr and they take you through the entire process step by step. When I do my L1, it's definitely a coin toss between the Zephyr and the SBR Fusion.

 

[ThirstyBarbarian]

To be a Class 1 rocket, it needs to be under 1.5 kilos (52.9oz), fully loaded on the pad — so that includes the fully built rocket (with the weight of construction materials, glue, and paint), all the recovery gear (including things like quick links, blankets or dog barf, chute release, etc.), the motor, motor hardware, retainer, and motor adapter if necessary — EVERYTHING! It seems like a 44oz estimate for the kit leaves some room, but it might be cutting it very close.

I love flying the biggest possible rockets at non-HPR launches. Big fish, little pond. It always impresses the new fliers and kids. And it’s great fun to fly a big rocket on a G motor and be able to stand 40’ from the pad. My favorite of this type of rocket built from a kit was my G-Force. It was a 4” diameter rocket, about 5 feet tall, but it was well under the weight limits when fully loaded with a G motor, even with some heavy decoration, upgraded recovery gear, and added retainer. You might consider that one. I think a LOC IV would probably easily qualify too. Those might have more of the look you are going for and not cut it quite as close as the Zephyr.

I used to fly my G-Force at every non-HPR launch. I liked the AT single-use G motors on the higher thrust end — G77, G78, G79, G80, all with 4-second delays. G38 and G40 were too low thrust. A single-use G74 would probably do it if you want a lower flight, and it’s economical. I think an F67 would be pretty low, and even a 4-second delay would be too long — good chance of a low flight, ejection well past apogee, likely crash! But you could sim it and see. The rocket would be a fine L1 rocket too. At HPR launches, I flew it on H motors all the time and an occasional I. The single-use G motors typically put it up around 500’ - 700’, so that‘s good for a smallish field. And H motors were probable around 1500’ give or take, and that’s a nice altitude for L1.

 

[Handeman]

What exactly is a non-HPR launch? G and below or Class 1 only? What about HPR G motors like a G138?
There have been a time or two that weather, ceiling, etc. have had us not called in the HPR waiver and we only allowed Class 1 rockets to fly. My PML Callisto on a H128W or H180W is a Class 1 so it could fly. Would that work?

 

[mtnmanak]

What exactly is a non-HPR launch? G and below or Class 1 only? What about HPR G motors like a G138?
There have been a time or two that weather, ceiling, etc. have had us not called in the HPR waiver and we only allowed Class 1 rockets to fly. My PML Callisto on a H128W or H180W is a Class 1 so it could fly. Would that work?

You don't need a waiver to fly a Class 1 flight, so you can fly those rockets at the local park, etc - but not with an HPR motor. I am assuming the OP wants to fly the rocket in local places where LPRs and MPRs are allowed, not at a club launch. If it is a club launch, then your point is valid.

 

[mtnmanak]

To the OP's original question, the short answer is "yes", but it depends on how much you are willing to mod the kit.

Some good suggestions in the thread about using light building techniques, trimming motor tubes, etc.

Your biggest weight savings would/could definitely come from the fins. The fins on my Zephyr account for just shy of 25% of the overall weight of the rocket. The fins that come from Apogee are some pretty heavy plywood. Excellent for that L1 cert flight, but not exactly svelte.

The easiest mod would be to take a jigsaw and cut out a large grid in the fins. You could leave it like that, but you would lose a lot of altitude to the wind resistance.

Next upgrade would be to fill the spaces you cut out with some foam and laminate the fins with lightweight fiberglass. This would get you a lot of weight savings and probably a boost in performance.

Finally, you could make your own fins. In my case, I CNCed some fins out of basswood and laminated them with carbon fiber. Very strong, super lightweight. That cut about 8 ounces off my rocket. Unfortunately, that rocket did come in ballistic last year, so I don't have pictures (had nothing to do with the fins, had a recovery malfunction). Laminating balsa would be even lighter.

If you go down the last path, you may as well cut your own centering rings as well. You could shave off an ounce or so with lighter rings and by ditching the "ribs" Apogee uses to space and center the rings.

Ditch the eye bolt and epoxy a kevlar attach point to the motor mount.

If you are willing to spend the money, replace the nylon shock cords with kevlar and use a high performance, lightweight chute like the Iris Ultra Compact from Fruity Chutes.

Go light on the paint (no primer) and leave the decals off.

For motor retention, go with a friction fit.

With a lot of discipline and some mod work, I bet you could get this rocket down to less than 35 ounces, dry weight. Zephyr builds are always fun, this sounds like a challenge I may want to try, how lightweight can you make a Zephyr... Sounds like a fun winter build.

 

[ThirstyBarbarian]

What exactly is a non-HPR launch? G and below or Class 1 only? What about HPR G motors like a G138?
There have been a time or two that weather, ceiling, etc. have had us not called in the HPR waiver and we only allowed Class 1 rockets to fly. My PML Callisto on a H128W or H180W is a Class 1 so it could fly. Would that work?

It’s true there are a few ways to define non-HPR. In my case, the club launches I’m talking about don’t allow anything that could be considered high power by any definition. So the pad weight has to be under 1.5 kilos, motors have to be G or lower, average thrust under 80 Newtons, propellant weight under 125 grams, no sparky motors, etc. And the clubs usually have had a low ceiling, like 1,000 or 1,500 feet. These clubs didn’t want to mess around with the edge case stuff, like a G125, where the individual needs a certification to buy it and fly it, but an FAA waiver is not required for the flight. I think a lot of it was motivated by keeping things as simple as possible to get landowner permission.

Technically, you can do a Level 1 cert flight at a non-waivered launch. Use a rocket under 1.5 kilos and keep the propellant mass under 125 grams. There are many popular motors that qualify, like the H115. If I owned a suitable property, I’d be doing this all the time.

 

[ThirstyBarbarian]

Personally, if I wanted a big Class 1 rocket, I would just buy something else. It probably could be done. I know someone who got a Minnie Magg down to Class 1 weight by skeletonizing everything and drilling tons of holes. But it’s a pain, and do you really want your rocket to be like that? I built a foam rocket to be the biggest Class 1 I could make, but ended up a few ounces over, and I really had to sacrifice some things to bring it back in line. Bought an ultralight chute, replaced the tubular nylon recovery harness with kevlar cord, got rid of the quick links, and a few other tricks. Not convenient.

 

[ShadowSpire48]

Zephyr is a pretty robust rocket it’s got some thick fins… Iam sure In the right situation damage can be done but that goes for any rocket. Zephyr has been a really Popular pick over the last 2 years for a L1 rocket. I myself also picked the zephyr. Likes high thrust motors and with 29mm or 38mm you can definitely find a motor to keep it 1400ft or lower range

Goblins a classic also . Seems like two great picks

Not denying that the Zephyr is a good choice BUT for what the OP wants to do, it's impossible without a lot of modifications. A Goblin is the better choice between the two in this case for flying as a class one and for L1 (and L2 if you want to).

 

[Mopo]

Thanks for all the sound suggestions, I will def consider if it is worth the trouble to go through with keeping the Zephyr class 1. Some of the mods are pretty simple, shortened tube, light glue, less primer/paint are def doable, but others like hollowing out the fins and laminating would be too much of a hassle for me and beyond my expertise. Didn't realize they were so hefty. On the one hand, I do enjoy the challenge and problem solving so I might decide to tackle this. On the other hand.. could just get a goblin... on the other hand... o wait I'm out of hands..

 

[ShadowSpire48]

Thanks for all the sound suggestions, I will def consider if it is worth the trouble to go through with keeping the Zephyr class 1. Some of the mods are pretty simple, shortened tube, light glue, less primer/paint are def doable, but others like hollowing out the fins and laminating would be too much of a hassle for me and beyond my expertise. Didn't realize they were so hefty. On the one hand, I do enjoy the challenge and problem solving so I might decide to tackle this. On the other hand.. could just get a goblin... on the other hand... o wait I'm out of hands..

You can always get the Goblin to fly locally and your L1 and then get the Zephyr later to play with and test the weight reductions.

 

[Handeman]

You don't need a waiver to fly a Class 1 flight, so you can fly those rockets at the local park, etc - but not with an HPR motor. I am assuming the OP wants to fly the rocket in local places where LPRs and MPRs are allowed, not at a club launch. If it is a club launch, then your point is valid.

Why not a HPR at a local park? If the rocket is Class 1 and you are certified and can abide by the safety codes for safe distances and launch site size, I don't understand why you would say it's not allowed.
If it is a local LPR/MPR club doing Class 1 launch at a park and they have special rules in addition to FAA codes as @ThirstyBarbarian explained, then I can understand that.

 

[ThirstyBarbarian]

Why not a HPR at a local park? If the rocket is Class 1 and you are certified and can abide by the safety codes for safe distances and launch site size, I don't understand why you would say it's not allowed.
If it is a local LPR/MPR club doing Class 1 launch at a park and they have special rules in addition to FAA codes as @ThirstyBarbarian explained, then I can understand that.

As a practical matter, around here you would never get permission from a park to fly something that size on your own. It’s hard enough to get permission to fly any rockets of any size at nearby parks, including Estes A, B, and C type rockets. It would be fine with the FAA, but not with the parks district, cops, or fire department.

My understanding is that one of the clubs I fly with used to have a site where they did fly up to maximum Class 1 rockets. So you could certify with that club, even though they never got FAA waivers. You could fly something like a LOC IV on and H135 and certify with a Class 1 flight. When I was ready to certify, someone suggested that I skip the club launch and just do it with some of my rocket buddies at the “secret spot”, but my rocket was over the weight limit.

 

[GalantVR41062]

Not a Zephyr but I acquired a MC Torrent 38mm mmt. I built this with the intent on flying as a class 1 rocket, and high power with only a recovery gear change.



The Loki 38mm G66 red motor is a little heavy but the hole rocket on the pad can weight in at 1,485 grams.

Rail velocity was a concern but I had already built a 1010 all aluminum pad with a full 86" rail length, I don't recall the usable guid length but happy with the flights pretty straight up to 700 feet.




For high power I change out the recovery gear and up the chute size. I have flown it on up to a Aerotech I 211W motor with motor eject, might try a small J some day.

 

[ThirstyBarbarian]

On the one hand, I do enjoy the challenge and problem solving so I might decide to tackle this. On the other hand.. could just get a goblin... on the other hand... o wait I'm out of hands..

Here, let me lend you a hand.

These are the rockets I mentioned as alternatives:

On the one hand, the G-Force:
https://www.buyrocketmotors.com/aerotech-g-force-rocket-kita/

On the other hand, the LOC IV:
https://locprecision.com/collections/rockets-4-00-diameter/products/loc-iv

 

[mtnmanak]

Why not a HPR at a local park? If the rocket is Class 1 and you are certified and can abide by the safety codes for safe distances and launch site size, I don't understand why you would say it's not allowed.
If it is a local LPR/MPR club doing Class 1 launch at a park and they have special rules in addition to FAA codes as @ThirstyBarbarian explained, then I can understand that.

Any rocket designated as "high power" is not a Class 1 rocket. By definition, if it is a "high power" flight, it is Class 2 and requires an FAA waiver to fly it.

Put another way, there is no way, by FAA regs and definitions, a high power rocket flight flight can be called Class 1:

https://www.nar.org/high-power-rocketry-info/understanding-faa-regulations/
This has become the perennial "what does 'high power' mean" thread. This dead horse has been beaten almost as much as "what is the best Level 1 Cert Rocket".

I am sure someone will hop on and "clarify" that FAA regs are different than NFPA recommendations.

But, by all means, if you can get the FAA to give you a waiver to fly high power rockets at your local park, I want to come where you are, because that would be a different FAA than the one we have in the US.

 

[novahobbies]

Been on this forum actively for 2 days and already so glad I joined. Learning so much. And yeah.....I'm also strongly thinking of adding a Zephyr to the rocket barn for whenever I decide to do my L1.

 

[LithosphereRocketry]

Any rocket designated as "high power" is not a Class 1 rocket. By definition, if it is a "high power" flight, it is Class 2 and requires an FAA waiver to fly it.

Put another way, there is no way, by FAA regs and definitions, a high power rocket flight flight can be called Class 1:

https://www.nar.org/high-power-rocketry-info/understanding-faa-regulations/

Nowhere in those regulations or in that explanation does it say that a class 1 rocket cannot be high-power.

From the US CFR website:


The FAA doesn't regulate motor classes at all-- they just leave it at 125 grams of propellant to need a waiver. NFPA 1127 does acknowledge the existence of letter classes, and requires that users of >160ns motors be certified, but they have no say in airspace classification. The NAR's site does say that "Class 2 covers high-power rockets", which is technically accurate but a little misleading: All Class 2 rockets are high-power (NFPA 1127 includes the conditions of being Class 2 as part of its definition of high-power), but not all high-power rockets are Class 2.

 

[mtnmanak]

Nowhere in those regulations or in that explanation does it say that a class 1 rocket cannot be high-power.

From the US CFR website:
View attachment 533305

The FAA doesn't regulate motor classes at all-- they just leave it at 125 grams of propellant to need a waiver. NFPA 1127 does acknowledge the existence of letter classes, and requires that users of >160ns motors be certified, but they have no say in airspace classification. The NAR's site does say that "Class 2 covers high-power rockets", which is technically accurate but a little misleading: All Class 2 rockets are high-power (NFPA 1127 includes the conditions of being Class 2 as part of its definition of high-power), but not all high-power rockets are Class 2.

Ummm.. Yeah, it EXPLICITLY says a high power rocket is Class 2:

Class 2 High Power Rockets​

The Class 2 rocket category covers high power rockets and is defined at 14 CFR 101.22 (b) and is listed as:

Class 2 – High-Power Rocket means an amateur rocket other than a model rocket that is propelled by a motor or motors having a combined total impulse of 40,960 Newton-seconds (9,208 pound-seconds) or less.

And, thank you for being that guy that brings up NFPA, bringing this full circle. Yup, you are comparing apples and oranges.

You are correct, the FAA does NOT, repeat NOT talk about motor letter designations, so why bring it up? It is completely irrelevant to the conversation. LPR and MPR are also irrelevant. The only thing that matters from an FAA perspective is "model rocket" vs. "high power rocket". I never said anything about G, H, I, etc motors.

The OP specifically asked about Class 1 rockets, which are, once again, by FAA definition NOT HIGH POWER rockets. The NFPA has nothing to do with Class 1 vs Class 2.

If you want to start talking about NFPA (which has no regulatory authority - it is a private organization), then we have to stop using the terms "Class 1" and "Class 2". Which is cool, but it is not what the OP asked about.

 

[rharshberger]

Ummm.. Yeah, it EXPLICITLY says a high power rocket is Class 2:

Class 2 High Power Rockets​

The Class 2 rocket category covers high power rockets and is defined at 14 CFR 101.22 (b) and is listed as:



And, thank you for being that guy that brings up NFPA, bringing this full circle. Yup, you are comparing apples and oranges.

You are correct, the FAA does NOT, repeat NOT talk about motor letter designations, so why bring it up? It is completely irrelevant to the conversation. LPR and MPR are also irrelevant. The only thing that matters from an FAA perspective is "model rocket" vs. "high power rocket". I never said anything about G, H, I, etc motors.

The OP specifically asked about Class 1 rockets, which are, once again, by FAA definition NOT HIGH POWER rockets. The NFPA has nothing to do with Class 1 vs Class 2.

If you want to start talking about NFPA (which has no regulatory authority - it is a private organization), then we have to stop using the terms "Class 1" and "Class 2". Which is cool, but it is not what the OP asked about.

You need to get off the soapbox, its important to understand ALL the regulations and codes that apply to our hobby. FAR 101, NFPA 1122 (model rockets), NFPA 1125 (rocket motor manufacturing), and NFPA 1127 (High Power Rocketry), NAR and TRA safety codes. In most of these threads Class 1 and Level 1 rockets get mixed up so its important to make sure the right classifications or cert levels are being talked about. If need be I will be the person that brings it up when there is a perceived need. RANT OFF!