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Is it possible? 38mm for Lv2?

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Ccolvin968

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So, is it correct that I will need to launch a J, K, or L motor for my Lv 2 certification?
Are there Reloadable J, K, and L motors that are 38mm?
What brand are they, and are they compatible with Aero Pack retainers?
I'll be studying throughout the No Launch season in MN due to -20 through -30 F temps.
Would it be in my best interest to just go buy another rocket and with a 54mm mount?
Any advice or guidance is appreciated.
 

Flyfalcons

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Sure, I'll be flying mine with either an Aerotech DMS J270W or reloadable J350W. Fairly popular motors for 38mm.
 

NateLowrie

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So, is it correct that I will need to launch a J, K, or L motor for my Lv 2 certification?
Are there Reloadable J, K, and L motors that are 38mm?
What brand are they, and are they compatible with Aero Pack retainers?
I'll be studying throughout the No Launch season in MN due to -20 through -30 F temps.
Would it be in my best interest to just go buy another rocket and with a 54mm mount?
Any advice or guidance is appreciated.
Aerotech, CTI, and Loki all has 38mm motors in J size. Loki has a K in the 38/1200 case.

54mm will give you a much larger range of motors in the J through L range.
 

bob jablonski

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There is a good amount of 38mm J options for L2 from all 3 major HP motor manufacturers. CTI is a bit thin at the moment but slowly coming back on line. Aeroech has 2 DMS loads J270W and J425 Redline and reload sets for 720 and larger 38mm cases. Good luck with your L2
 

Ccolvin968

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What do you mean by 720 and larger 38mm cases?
I only know of case sizes by grain.
Thanks for the help!
 

rharshberger

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What do you mean by 720 and larger 38mm cases?
I only know of case sizes by grain.
Thanks for the help!
Aerotech doesn't use grain capacity, but a 720 ( Total theoretical newtons capacity )iirc is a 6 grain equivalent .
 

neond7

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Here is my recommendation - build a rocket with a 54mm mount. You can use an adapter to fly a 38mm motor in a 54mm mount. Then when you are ready, you can the full range of 54mm motors. I think J motors are the largest 38mm motors.

I have personally found the 5.5" airframes the most versatile rockets as they can fly on J up to L motors. My first 5.5" rocket was a LOC Big Nuke that I still fly on K motors all the time.
 

watermelonman

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I think most people certify L2 on a 38mm rocket.

I think most L2 certified people quickly decide they want a 54mm rocket.
 

mccordmw

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Here is my recommendation - build a rocket with a 54mm mount. You can use an adapter to fly a 38mm motor in a 54mm mount. Then when you are ready, you can the full range of 54mm motors. I think J motors are the largest 38mm motors.

I have personally found the 5.5" airframes the most versatile rockets as they can fly on J up to L motors. My first 5.5" rocket was a LOC Big Nuke that I still fly on K motors all the time.
+1 to this. I built my Binder Design Excel Plus with a 54mm mount. I used a 54>38 adapter to fly on a 38mm 4-grain I242. For my L2, the adapter is out, and I'm flying on a 54mm motor. 54mm supply seems really rough right now until CTI production is back up. Availability has me planning my L2 on a 3 grain J380 SS.
 

Rex R

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my l2 bird (competitor 3) has a 54mm motor mount, did my L2 with a 38mm AT J350 (nice motor, great sound and flame) using an aero pack 38/54 adaptor.
Rex
 

Bat-mite

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Get a MAC Performance 4" kit with a 75mm MMT. Adapt it down to 54mm for your Level 2, then stick a baby M 75mm in it for Level 3.
 

Ccolvin968

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This is great info guys! I really appreciate it.
I guess I just gotta weigh my options and see which route I want to take.
 

Ccolvin968

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Yep. We have waivers up to 20,000 and there were people launching M sized motors last month.
Thank you for your advice.
 

cerving

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I think most people certify L2 on a 38mm rocket.

I think most L2 certified people quickly decide they want a 54mm rocket.
Doing L2 with 38mm gives you an easy way to test it with L1 motors first to make sure everything is gonna work. It also gives you a good excuse to get a bigger rocket after your L2 cert... :)
 

Handeman

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I agree with the folks recommending a 54mm for L2 rocket. I scratch built my L2 with a 54mm MMT and used a K695R Aerotech motor for the cert. That rocket had it's 35th flight this weekend. It flies a lot because it is so versatile. It is a DD rocket and has flown to 1100 ft on an I211W 38mm AT motor and +9500 and over Mach with a CTI Pro54 L935.

The only thing that would give you more versatility would be a 75mm MMT. You can adapt it down to 38mm or push the limits with 75mm full L motors, and as Bat-mite said, a small M would fit too if the fin can is long enough.

As other have said, you have to fly the field. The thing about doing a L2 cert on a 38mm rocket is that they tend to be light so you can fly them on 38mm H motors. When you do the cert on a J motor you are usually looking at over 3000 ft. and maybe over 5000 ft. That isn't an issue if it is a DD rocket, but most people doing a L2 cert with a 38mm don't have a DD rocket. The question become, can you fly that high with motor ejection on your field? A Jolly Logic Chute Release can make a huge difference in that situation, but still, how many L2 motors can you fly in that rocket? You will have to go to 54mm or larger if you want to fly a K or L motor so why not start out with that for your cert?
 

Ccolvin968

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I completely understand your altitude concerns, but I'm lucky enough to fly with a club that gets waivers up to 20,000 on the regular with no issues from what I've heard. They also state it on their website. I just gotta decide what my next rocket will be! xD HELP!! I CAUGHT THE BUG! :D :D :D
 

rharshberger

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We all have suggestions, usually I like to suggest upsizing the motor mount by one size, if you plan to fly 38mm's then upsize it to 54mm's and fly with an adapter that way you have the option of flying more powerful or just different motors than the 38mm selections. Save the larger motor mounts and rockets for later builds, for example building a rocket for a 75mm motor is really not a lot different than building one for a 54mm, but along the path to high impulse motors you also learn about proper construction techniques to handle the power the larger motors are capable of.
 

scsager

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Lots of 38mm J motors available. I did my L2 on a CTI 38mm 6-grain J330. My wife will attempt hers on a Aerotech 38mm DMS J425.

When you have questions about motors... >>> http://www.thrustcurve.org/
 

DavidMcCann

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Take a good hard look at how much you want to be spending per launch. Realize that popping off a K is a great way to burn up $100 every 2 seconds ;). If you're not flying a bunch of K/L motors, you may enjoy a 38 mount in a smaller rocket more. If you've got the budget, then going for a 54 makes sense.
 

KenRico

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I usually oversize my MMT as you can always adapt down..not up.

I flew a Vindicator DD a beast of a 4 inch fiberglass kit for L2 with a 54 to 38 adapter and a J350 White Lightning for a nice low certification flight.

Most versitile rockets out are Punisher by Wildman , have flown on an H and seen flown on a L .. close is the Formula 75 on sale today at Madcow. 3 inch rocket with a 54mm mmt would allow you to try the Aeropack Tailcone retainers too, just ask to pay the difference on a longer mmt.

Kenny
 

DavidMcCann

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To get away from the "this rocket is most bitterest!" and reply to the motor part.....Yes, a 38mm L2 rocket is possible. (from thrust curve)


MotorTypeDiamImpulseAvg ThrBurnPropellantHardwareFiles
AeroTech J340reload38651.7Ns354.1N1.8sMetalstormRMS-38/7201
AeroTech J420reload38658.0Ns420.0N1.6sRedlineRMS-38/7204
AeroTech J425SU38676.0Ns425.0N1.6sRedline1
KBA J740reload38682.0Ns815.0N0.9sMojave GreenAMW 38-6401
AeroTech J350reload38700.0Ns445.0N1.5sWhite LightningRMS-38/7202
AeroTech J270SU38703.0Ns270.0N2.6sWhite Lightning1
AeroTech J500reload38723.0Ns500.0N1.4sMojave GreenRMS-38/7202
AeroTech J575reload38798.1Ns594.0N1.3sFast BlackjackRMS-38/10802
AeroTech J570reload38973.1Ns509.3N1.9sWhite LightningRMS-38/10804
AeroTech J825reload38974.9Ns892.9N1.2sRedlineRMS-38/10802
AeroTech J510reload381162.0Ns509.9N2.3sWhite LightningRMS-38/13201

MotorTypeDiamImpulseAvg ThrBurnPropellantHardwareFiles
Cesaroni J94reload38644.0Ns94.4N6.8sMellowPro38-5G1
Cesaroni J285reload38648.0Ns287.5N2.3sClassicPro38-5G2
Cesaroni J335reload38649.2Ns335.5N1.9sRed LightningPro38-5G1
Cesaroni J270reload38650.3Ns270.8N2.4sGreen3Pro38-5G2
Cesaroni J316reload38654.3Ns315.1N2.1sPinkPro38-5G2
Cesaroni J357reload38657.6Ns357.0N1.8sBlue StreakPro38-5G2
Cesaroni J381reload38659.9Ns380.6N1.6sSkidmarkPro38-6G2
Cesaroni J290reload38683.6Ns295.4N2.3sWhitePro38-5G2
Cesaroni J400reload38700.0Ns402.1N1.8sSmoky SamPro38-6G2
Cesaroni J330reload38765.0Ns325.3N2.3sClassicPro38-6G2
Cesaroni J410reload38773.8Ns408.9N1.9sRed LightningPro38-6G2
Cesaroni J425reload38783.9Ns426.9N1.8sBlue StreakPro38-6G1
Cesaroni J354reload38818.7Ns354.7N2.3sWhitePro38-6G2
Cesaroni J520reload38848.4Ns519.4N1.6sSkidmarkPro38-6GXL2
Cesaroni J580reload38896.4Ns577.4N1.6sSmoky SamPro38-6GXL2
Cesaroni J150reload38949.2Ns148.4N6.4sMellowPro38-6GXL1
Cesaroni J394reload38970.4Ns394.1N2.5sGreen3Pro38-6GXL2
Cesaroni J595reload38985.0Ns595.4N1.7sBlue StreakPro38-6GXL2
Cesaroni J600reload38998.6Ns603.5N1.7sRed LightningPro38-6GXL2
Cesaroni J420reload381007.8Ns419.9N2.4sClassicPro38-6GXL2
Cesaroni J453reload381012.6Ns452.7N2.2sWhitePro38-6GXL2
Cesaroni J530reload381115.5Ns531.2N2.1sImaxPro38-6GXL2



MotorTypeDiamImpulseAvg ThrBurnPropellantHardwareFiles
Loki J396reload38650.0Ns396.0N1.7sSpitfire38-7402
Loki J320reload38720.9Ns335.0N2.2sLoki Red38-7402
Loki J528reload38741.0Ns528.0N1.2sLoki White38-7402
Loki J712reload38751.9Ns641.1N1.2sLoki Blue38-7402
Loki J650reload38942.0Ns648.0N1.5sSpitfire38-12002
Loki J1000reload381220.0Ns976.0N1.3sLoki White38-12002
Loki J1026reload381267.0Ns1026.0N1.2sCocktail38-12002
MotorTypeDiamImpulseAvg ThrBurnPropellantHardwareFiles
Loki K1127reload381285.0Ns1029.0N1.2sLoki Blue38-12002
Loki K627reload381519.0Ns627.0NLoki Red38/12001
 
Last edited:

Ccolvin968

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I can't seem to find the 38mm J's from any company in Openrocket to sim them.
Any ideas if I'm missing something?
I don't have any filters set.
 

Tonimus

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If you post your file, we could look it over.
 
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