Level 3 certification flight and subsonic speeds

[Dillon Mayberry]

I am working on my Tripoli level 3 certification and I was wondering if it is possible to achieve the certification without having to go supersonic. I know the rules don't say anything regarding super vs sub-sonic speeds, but any design I make ends up with a max velocity of around Mach 1.65.

 

[rfjustin]

I am working on my Tripoli level 3 certification and I was wondering if it is possible to achieve the certification without having to go supersonic. I know the rules don't say anything regarding super vs sub-sonic speeds, but any design I make ends up with a max velocity of around Mach 1.65.

How about some details of your rocket and intended motor? 4" airframe, 3" hole?

What concern/problem are you solving for by not going supersonic?

What practical flight experiences have you had to date?

Welcome to the jungle...

 

[loopy]

Sounds like you need a bigger diameter. What are your design parameters?

 

[Titan II]

I am working on my Tripoli level 3 certification and I was wondering if it is possible to achieve the certification without having to go supersonic.

Yes. It is common practice.

 

[tsmith1315]

any design I make ends up with a max velocity of around Mach 1.65.

A full scale V2 should slow that down for you:

 

[pathtouch]

My 6” airframe on an M1315 sims subsonic.

 

[kswing]

I did my L3 with a 7.5" airframe and it stayed subsonic on an M1350.

 

[jkovac]

My L3 flight was subsonic at Mach .86 max velocity. 6” Wildman Ultimate on an M1790. I didn’t purposefully configure the flight to stay subsonic, though. As rfjustin asked, why is it that that you specifically want to stay below Mach 1?

 

[mtnmanak]

Build a BALLS or an LDRS and it should go low and slow.

 

[mtnmanak]

And, consult your TAPs/L3CCs. They are the only one's who have an opinion that matters when you go to your cert launch.

 

[Steve Shannon]

I am working on my Tripoli level 3 certification and I was wondering if it is possible to achieve the certification without having to go supersonic. I know the rules don't say anything regarding super vs sub-sonic speeds, but any design I make ends up with a max velocity of around Mach 1.65.

Design something with a larger diameter.

 

[KenECoyote]

I am working on my Tripoli level 3 certification and I was wondering if it is possible to achieve the certification without having to go supersonic. I know the rules don't say anything regarding super vs sub-sonic speeds, but any design I make ends up with a max velocity of around Mach 1.65.

OOC, What was your L2 rocket?

 

[cbrarick]

supersonic, subsonic, just a dot on the speed chart. Means nothing more as long as you punch transonic quickly.
Don't freak out over it.
one of my LDRS goals is to punch thru 1,800 mph with a unmodified big nuke 3E in the drag race. After all, second place is just first looser.

 

[2-0turbo]

My L3 flight was subsonic at Mach .86 max velocity. 6” Wildman Ultimate on an M1790. I didn’t purposefully configure the flight to stay subsonic, though. As rfjustin asked, why is it that that you specifically want to stay below Mach 1?

“Because it’s a wall man! You won’t survive!” You can’t break the sound barrier! It’s called a barrier for a reason!

 

[bjphoenix]

My L3 flight was subsonic at Mach .86 max velocity. 6” Wildman Ultimate on an M1790. I didn’t purposefully configure the flight to stay subsonic, though. As rfjustin asked, why is it that that you specifically want to stay below Mach 1?

The only L3 I've witnessed in many years was also subsonic, probably much slower than yours. I think that rocket was at least 8" diameter.

 

[thzero]

I am working on my Tripoli level 3 certification and I was wondering if it is possible to achieve the certification without having to go supersonic. I know the rules don't say anything regarding super vs sub-sonic speeds, but any design I make ends up with a max velocity of around Mach 1.65.

Not trying hard enough? Or big enough?

My 5" fiberglass l3 that I'm getting together gets close but is still under mach per sims, so will be under in reality

 

[thzero]

supersonic, subsonic, just a dot on the speed chart. Means nothing more as long as you punch transonic quickly.
Don't freak out over it.
one of my LDRS goals is to punch thru 1,800 mph with a unmodified big nuke 3E in the drag race. After all, second place is just first looser.

Or loser. But hey who is counting

 

[-Slick-Ice]

I'm going to use the AeroTech M650 for mine with 5.5" LOC IRIS.
This will be M.70.

 

[cbrarick]

we'll see about the loss, I don't think so. It's a hot motor. I have ways of getting it going fast.....

 

[RocketPro]

I'm going to use the AeroTech M650 for mine with 5.5" LOC IRIS.
This will be M.70.

I recommend that you discuss with your TAP/L3CC how that motor gravity turns early…it’s a long, heavy motor with not a lot of thrust by the time you’re off the rail. Just my experience with flying that motor. It’s kind of a sustainer motor for 2nd stages. Last time I flew that motor by itself in an all CF rocket it recovered 4 miles downrange…YMMV.

 

[-Slick-Ice]

I will definitely keep that in mind.

 

[ghuber]

Tube fin? My L3 was a 29lb (with motor) 4" Fiberglass tube fin. On an M1350 it topped out at mach .93 and max. altitude was ~8300 feet.

 

[Tom Flint]

Mine was made from PML 11.4" tubing and simmed out to 520 mph max on an M1939.

 

[Buckeye]

Level 3, huh?

 

[Handeman]

I am working on my Tripoli level 3 certification and I was wondering if it is possible to achieve the certification without having to go supersonic. I know the rules don't say anything regarding super vs sub-sonic speeds, but any design I make ends up with a max velocity of around Mach 1.65.

I don't think I've ever seen a L3 project go super sonic, and I've probably seen +100 flights over the years. There may have been one or two at an LDRS at URRG. The reason is I'm on the east coast. Most flights say under 8,000 ft. and you can't really exceed Mach and stay under that with a L3 motor.

 

[FredA]

On the east coast, it's hard to go supersonic and keep it under the short waivers.
Out west it's a different story.
I've seen plenty of supersonic L3's including my own.

Frankly think supersonic and successful dual-deploy should be the required flight profile for an L3, but that's me.

 

[Rschub]

Lol, this "guy" has exactly 1 post and has not replied. Meanwhile there are 26 replies and many views.

I suspect these type posts are AI generated to stimulate interest, views, site traffic and ultimately ad revenue.

If I am banned it was nice knowing you all.

 

[FlyBy01]

Is the original poster going to chime in or did they drop a grenade to see who would jump on it

 

[KenECoyote]

Maybe OP had a typo and it's "Level 2"?

 

[jkovac]

I think Rschub is right about this not being real. One post at 8:15 a.m. last Wednesday and signed off immediately, never even logged back on to see if anyone replied. The question they posted seems coherent by itself, but it is odd that someone preparing for a L3 cert would ask that.