L3 Build 4”,5” or 6”

I am planning on building my L3 project over the winter. I had originally planned on scratch building a 6” Astrobee D but with the Black Friday sales just around the corner the price of a kit may be just too good to pass up. So what I have been looking at are the 5” and 6” kits from Performance Hobbies, Wildman and Madcow. I also have enough parts lying around to build a 4” with a 75mm MM. I live in the northeast and am probably going to fly this at URRG with its 18k waiver. Here is my short list of pros and cons so far:

4”- pros: I have most of the parts I need so low cost. I can fly it on J motors. High performance flyer, A regular addition to the fleet that would be flown frequently.
-cons: Not much different than some of the rockets in my current fleet. Not super challenging

5”-pros: A nice compromise between a 4” and 6”. Still a high performance rocket with a M motor but that can be flown on a big J motor.
A nice “Big” rocket. Would probably be flown a couple of times a year.
-cons: More costly than going with the 4” option. Not a really “Big” rocket (see 6”)

6” -pros: A really BIG rocket with presence. A fun and challenging build. A slower and lower flyer that would be less risky for a Cert flight.
-cons: much higher cost. Would probably only be flown once a year at most

So what I would like to know is your opinions on which would make a better choice for my L3.

I would not fly a four inch rocket on M motors at Potter.

I flew a Performance Rocketry 5” Competitor for my L3. Great rocket when PR made it.

I would absolutely fly a 4” rocket on a 76-6000 in Potter. Just fly GPS and you’ll be good.


Sent from my iPhone using Rocketry Forum

Compromise- I just did my L3 on a 6" v2, which isn't a "monster" rocket.. it has a 75mm motor mount in the boat tail, so I guess it's between 3" and 6" Honestly, I probably will only fly it on M motors once per year- it's small enough that I could fly it on a high thrust K motor (like a K1440WT), so I'll do that more often.

patelldp said:

I flew a Performance Rocketry 5” Competitor for my L3. Great rocket when PR made it.

I would absolutely fly a 4” rocket on a 76-6000 in Potter. Just fly GPS and you’ll be good.

Click to expand...

We all have different tastes I suppose. I was trying to fit a six pack into my new Dominator 4 to fly it on exactly those motors, but it still goes too high for me that field.

I also have no desire to pay a three digit sum to professional tree climbers.

Your so lucky that the Black Friday sales are coming up. I purchased a 5.5” AGM Pike from MadCow during last years Black Friday sale. MadCow’s price was a steal during the sale. I was able to pass my Level 3 Certification Flight test at Potter in October. The Pike flew to 8042 feet on a CTI M1810.

I wouldn’t fly a 4” M rocket at Potter either. There are simply too many darn trees around. My thinking at the time was to purchase the 5.5” Pike and fly it with the smallest M class motor possible to keep it low. I ended up having to use a bit higher power M motor than I had intended. This was because of the CTI availability issues.

If you are thinking about MadCow’s Pike, there are a couple of modifications that I would recommend. First purchase a 12” longer payload tube from MadCow. The rocket needs an insane amount of lead added to the nosecone otherwise. You can private message me for other advice on this kit if you decide to go that way.

This year I am going to buy a Wildman Ultimate Wildman if they are offered at a good deal on Black Friday.

All the best wishes on your Level 3 Project regardless of what kit you decide to buy.

Sincerely,
Bob

My TAP advised me to fly something bigger than a 4" I learned a lot more flying a 40 pound rocket and dealing with that much weight during recovery than I would have flying a 15-25 pound rocket (or as he put it - a level 2 rocket with a level 3 motor).

Good luck with your project!!!!

AndrewW said:

I am planning on building my L3 project over the winter. I had originally planned on scratch building a 6” Astrobee D but with the Black Friday sales just around the corner the price of a kit may be just too good to pass up. So what I have been looking at are the 5” and 6” kits from Performance Hobbies, Wildman and Madcow. [...]
So what I would like to know is your opinions on which would make a better choice for my L3.

Click to expand...

I'm with you in the M-motor capable rocket shopping mode.
For me it boils down to:
(1). Where will I fly it all year round?
(2). What motors will I fly it on all year round?
(3). What is your target L3 field's FAA waiver (to avoid busting through it on a 4" rocket!) ?

I would hate to build a nice big rocket and only fly it once a year.
To me, that's a waste of an opportunity to have all-year fun with your big investment of labor and love.

6+" rockets put you into 98mm motor category. That's K+ motors, at $170+/flight. Can you see doing that monthly?
If not, step down into 75mm motor space, and most commercial kits for 75mm that I've looked at are 4.0+5.5" in diameter and 14-28 lbs in weight. Flying K+ 75mm motors runs you $130+/flight. A little better.
Or throw in a 54/75 adapter, and fly 54mm I's/J's (if weight allows) at $40+/flight. That I can do all year round!

So for me, having a rocket that is light enough to fly on I's/J's is a huge plus, thus I'm shopping for a sub-20 lbs 75mm MMT rocket.
That could be Wildman AAD-98, Madcow Terminator or AGM-33 Pike, or something from MAC.

Your considerations may be different.

Good luck!

a

afadeev said:

I'm with you in the M-motor capable rocket shopping mode.
For me it boils down to:
(1). Where will I fly it all year round?
(2). What motors will I fly it on all year round?
(3). What is your target L3 field's FAA waiver (to avoid busting through it on a 4" rocket!) ?

I would hate to build a nice big rocket and only fly it once a year.
To me, that's a waste of an opportunity to have all-year fun with your big investment of labor and love.

6+" rockets put you into 98mm motor category. That's K+ motors, at $170+/flight. Can you see doing that monthly?
If not, step down into 75mm motor space, and most commercial kits for 75mm that I've looked at are 4.0+5.5" in diameter and 14-28 lbs in weight. Flying K+ 75mm motors runs you $130+/flight. A little better.
Or throw in a 54/75 adapter, and fly 54mm I's/J's (if weight allows) at $40/flight. That's I can do all year round!

So for me, having a rocket light enough to fly on I's/J's is a huge plus, so I'm shopping for a sub-20 lbs 75mm MMT rocket.
That could be Wildman AAD-98, Madcow Terminator or AGM-33 Pike, or something from MAC.

Your considerations may be different.

Good luck!

a

Click to expand...

Your safest bet--LOC Precision 7.5"

From the Ether...

IMO, go with 5", 5.5" or 6" glass from Madcow or Wildman for URRG/Potter site.

I’m planning a 4” wildman on a Loki M2550LB at Potter.

Its not impossible, just adds some things to watch. Going high at Potter means watching the winds, and sometimes canceling flights. With the right winds, stuff will drift right down the old lakebed. I’m in no hurry, so this plan works for me. Had a great day this September, but I missed it.

In the end, do what makes you happy. They’re all good options.

Wanna do it on the cheap 4in. is way to go. You probably have chutes, cordage for this size on hand.
Small M's will carry most fiberglass 4's to 13-15,000ft. And those M's cost under 250.00 Off top of my head 7-8 at least available in that price range.

Comfortable with that...go for it.

Or just wait and see what grabs your eyes on upcoming sale and buy something that REALLY floats your boat.
Keeping in mind all the added expense in upsizing EVERYTHING due to weight . You'll probably be in for 700-1200 added expense.

3rd option is build the 4 for almost 0 since you have parts on hand, get L-3 the easy way.
Buy something on sale, take your time and acquire needed extra stuff over time from yard sale & E-bay, as there are always guys getting out and selling stuff cheap.

Have your cake and eat it too...Lol

BUT ALWAYS keep in back of your mind, how high your project is going to fly, where you can fly it, AND the added cost of BIG motor required to do so.

If you keep logic in the equation, it will all make more sense for future purchases.
Good luck & have fun, what ever you decide!

Keep in mind I see very few large L-3 rockets flying more than once every year or 2 after obtaining the L-3 status, due to cost of motors. And the drudgery of hauling a monster out of the field after flight.

I'm a newly minted L2, so a long way till L3. But I (and it sounds like you) have a deep enough build pile / fleet already that for any kit purchases going forward I definitely am asking "Does this add any capabilities to my fleet? Does it provide any challenges I haven't already mastered?"

So I pulled the trigger on the Madcow Apache deal to start toying with 2-stage. I might get a 4" 54mm/75mm fiberglass bird (all my FG is 3" or smaller) so I can fly L2 motors a little lower. But that's it.

For you, it sounds like a 4" doesn't add much to your skills or your fleet (although if you've got the parts anyway...). Maybe you won't fly a heavier bird very often. But you probably won't fly your 4" very often either if it's just one more rocket in the rotation.

Someone mentioned 7.5" LOC kits, which might be interesting. Big, impressive, and draggy, but not too heavy to require huge chutes or be impossible to loft on L2 motors.

My L3 rocket was a scratch-built 6" IQSY Tomahawk, very similar to an Astrobee D. I flew it at Geneseo on a 3" AMW M. Went to 6500 ft. Since moving 10+ years ago to New Mexico, I've flown it to 7500 ft on a variety of M's. (My avatar is the rocket on an AMW M Skidmark).

I went with the cheaper route of starting with PML tubing and fiberglassing it myself. It also comes out lighter so I have more options on motors. I also saved money on the parachute by using a 12-ft "play chute" and added extension lines to it.

A full fiberglass kit will be less work, more money, and you won't learn as much from the experience.

A 5" or 4" rocket will be easier to transport, and give you more motor options. But the 5" all-glass will come out as heavy as the 6" glass-over-kraft. The 4" will add extra recovery challenges you don't need for you L3 flight at Potter. And you won't be able to enjoy seeing the flight the whole way up and down.

https://photos.app.goo.gl/jr4jLEJG3lhhyGr12

The 11.5" Madcow Cowabunga Mammoth was not available yet when I was deciding on a L3 cert rocket but if I were picking one now that is probably what I would build.

I would personally go for larger for L3. Mine was an 8.25" Nike Smoke. As someone mentioned, it has a presence! It is also a part of my long-term two-stage 1/2 scale Nike Apache, and had been for years before I started building it. I don't plan on spending $1200-$1800 for fuel (N-O $AUD cost down here in Oz) on a frequent basis.

My recommendation is to go for something big, and with some character. Something like the Phoenix missile style I quite like. You need to figure out what you like

Build it for larger motors but fly it later on smaller motors if you like, or build other smaller performance rockets to fly on the smaller motors. You don't have to trot out your L3 project on a regular basis, but the crowd does love them!

This simply comes down to your budget and flying fields.

A four inch is the least expensive and can be flown on smaller motors. You can test it on a big j motor and fly it a bunch on K motors. This the route I went. I had to travel three hours to do my level 3 as it would break the local waiver.

A five inch is a nice compromise. K motors and up likely, but that is ok.

A six inch is cool. Probably L motors and up.

What is the waiver at the fields you frequent?


Sent from my iPhone using Rocketry Forum

Thank you all for such great feedback! I think my plan at the moment is to continue to build the 4” to fly on M power and to seek out a good deal on a 5” at one of the sales this week. As much as I would love to build one of those attention grabbing +6” monsters the cost of flying one more than once is pushing me towards a smaller airframe. I am also a bit of a performance junkie so the smaller 4” and 5” fit more inline with my goals. I am leaning towards a Performer 125 at the moment but am curious to see what pops up this coming week.

My next problem is what motor to invest in. I currently have only CTI hardware up to a 54mm 4G and will need to figure out what to invest in for my L3 motor. I had originally thought to by an Aerotech M1350 single use motor for the cert flight but I am now leaning towards buying some hardware and a reload instead. I made a decision a few weeks to pursue my L3 as my next goal in rocketry but that meant putting my EX aspirations on hold for a bit but that being said I would like to invest in hardware that would lend it self to both functions. I have been very happy with the CTI stuff but have been looking at the stuff from Loki lately. Any suggestions on what you all found to be a worthy investment would be appreciated as it is starting to look like the propulsion side of the L3 equation is going to be the largest financial burden.


Sent from my iPhone using Rocketry Forum

I’ve got 76/6000 hardware you’re welcome to use, and we’re got someone at Urrg with anything you’d need likely.

DavidMcCann said:

I’ve got 76/6000 hardware you’re welcome to use, and we’re got someone at Urrg with anything you’d need likely.

Click to expand...

Dave, thank you so much for the generous offer. I will likely take you up on it. One of the reasons I was looking at Loki was that I would like to support Teddy from One Bad Hawk and borrowing hardware would definitely soften the blow a little bit. I saw the sale Chris is having at CSRocketry but I would much prefer to buy from someone I see at most of my local launches. And it goes without saying that I would replace the hardware if I lost it.

Whatever you choose, enjoy the journey.

I'm in the same boat, starting to look at an L3 project. For motor hardware I was looking at the Aerotech RMS 75/6400 case and a 75mm reload adapter system (spacers and floating forward closure). That would allow me to fly 75/6400, 75/5120, and 75/3840, L through M, reloads, and some CTI reloads as well. What ever you select, have fun!! :smile:

How about a 6" lower body tube transitioning to a 4" upper payload section. Best of both worlds!

Swissyhawk said:

How about a 6" lower body tube transitioning to a 4" upper payload section. Best of both worlds!

Click to expand...

Flip it and make an upscale Ventris?

Sorry I'm a little late to your rocket discussion, but I wanted to respond because I did your choice #1 for my L3. Your advantages and disadvantages are pretty accurate. I have a 4" Xcelerator (54mm mmt) I set up with redundant altimeters and flew on J to L. It made the L3 easy and low cost. All I had to buy was the kit with larger mmt, which was on sale in last year's black Friday sale (Wildman Drago XL) and the 75mm aeropack retainer. Transferred the av bay, harnesses, chutes, tracker from the Xcelerator and it was ready. I knew what to expect and had an accurate sim based on my existing rocket performance.

Cheap and easy, can fly on large J, got me to the 2 miles and squarely into Mach milestones in one launch. PLUS I also have spare parts I can swap between rockets. The entire top half from the av bay up can be used as a spare if needed, an advantage in case I were to lose the nose cone or something. Easy to haul to the pad, no special pad is needed, doesn't take up too much room in the garage.

As you said, it wasn't much of a challenge or learning experience other than building a 75mm motor.

Since I have the 54mm mmt rocket and 75mm motors are spendy, it hasn't flown since even though I can fly it on a J. I figured a large project that could only eat expensive L and M motors would rarely fly, that ended up happening anyway.

I'm still happy with the choice I made and I would do it again. I can work my way into larger rockets, learning more and challenging myself now that I already have my L3.

As far as motor hardware, if you only plan on launching a big motor once a season maybe you can borrow from another flyer.

DavidMcCann said:

I’ve got 76/6000 hardware you’re welcome to use, and we’re got someone at Urrg with anything you’d need likely.

Click to expand...

Very cool,, that's really very nice of you Dave..

AndrewW said:

Dave, thank you so much for the generous offer. I will likely take you up on it. One of the reasons I was looking at Loki was that I would like to support Teddy from One Bad Hawk and borrowing hardware would definitely soften the blow a little bit. I saw the sale Chris is having at CSRocketry but I would much prefer to buy from someone I see at most of my local launches. And it goes without saying that I would replace the hardware if I lost it.

Click to expand...

I was going to say the same thing as David did Andrew..
Thank you so much for thinking of me as well..
You're always welcome to borrow hardware from me...

As far as the rocket goes,,
I don't think you should build something that's similar to your other builds..
For me I try to make each build something new and different,, keeps things new and novel for me..
In your shoes I think that'd be size,, a big rocket with a big presence...
A 6" build,, like any one of the Ultimates will be able to fly on high thrust K's-- maybe questionable but surly on an "L"..
My buddy Steve M built an Ultimate and flew it on an L 1482 LB to shake it out... Beautiful flight,, just as was his cert on the M 1650 CT...
Another 6" Ultimate went up at METRA which has a low waiver on a 54 / 2800 L 1400 LW...
Lept off the pad with authority,, I wish I knew some numbers for that flight...
Many options,, you don't have to not fly the rocket because it's big,, it just restricts your motor choice a bit...

Teddy

Ohh yeah,,
On my last order someone asked me for an M 1650 CT and I ordered it for him...
I cannot for the life of me figure out who this was...
So I have one in stock,, lol..
I also have a few "L"'s in stock for the 76 / 3600 case...

markkoelsch said:

This simply comes down to your budget and flying fields.

A four inch is the least expensive and can be flown on smaller motors. You can test it on a big j motor and fly it a bunch on K motors. This the route I went. I had to travel three hours to do my level 3 as it would break the local waiver.

A five inch is a nice compromise. K motors and up likely, but that is ok.

A six inch is cool. Probably L motors and up.

What is the waiver at the fields you frequent?


Sent from my iPhone using Rocketry Forum

Click to expand...

Mark's advice is the one to follow. You got a field with the waiver? Do 4 inch and make sure you have the tracking skills and hardware to find it. Doing it on the playa? Ya better have a good GPS tracker.

Don't have the waiver? The unfortunate choice is to go larger and heavier. Problem there is having the storage space sometimes after the flying is done. Kurt

Bobfly said:

Your so lucky that the Black Friday sales are coming up. I purchased a 5.5” AGM Pike from MadCow during last years Black Friday sale. MadCow’s price was a steal during the sale. I was able to pass my Level 3 Certification Flight test at Potter in October. The Pike flew to 8042 feet on a CTI M1810.

Click to expand...

That was you? Congratulations on that great flight! I meant to stop by in person, but beforehand I was too busy preparing my beloved Punisher 4, and afterwards I was too busy sulking over its loss.

Beautiful rocket.

CJ was one of my TAPs and I went the 4" route, and it went great...L3 done. I also flew from a dry lake bed in Nevada, so when my Wildman Darkstar Extreme went to 14.5k on the M1780NT and just over Mach, it was not a problem. The main downside was that I lost visual after motor burnout and did not see it again until the tracker took me to it already on the ground, 20 mins later. Lots of roar and moving out with a purpose, then silence and not knowing what the heck was going on. In hindsight it all worked out fine, but I build something to stay in visual range the whole flight if I were to do it again.

After getting my L3, I flew my MadDog 6" on a 98mm M1939 (really a 2% N motor), and even that beast of a rocket when to 14.3k and out of sight for most of the flight. So, keep in mind how to want to enjoy the flight and the limitations of your field. If you want or need to see most of the flight, I'd go no smaller than a 6" rocket. An 8" rocket with a punchy, 75mm motor that will not go too high could be kept in visual range the whole time.