Build thread - 24mm supersonic rocket

[teepot]

At LDRS in the summer. I might fly it on some D's before that though.

I'll be there too. I'll watch for it.

 

[thzero]

Planning on flying on D's and E's until LDRS, when I will shoot it on the F44, and if it doesn't reach mach, I will buy a casing and fly it on a G.

Which G?

 

[user 35280]

https://www.apogeerockets.com/Rocket-Kits/Skill-Level-2-Model-Rocket-Kits/Aspire

 

[diyaerospace]

By the way, how will you tell if your rocket breaks mach?

 

[James Kobel]

At LDRS in the summer. I might fly it on some D's before that though.

Get the CTI 6G case!

 

[jqavins]

https://www.apogeerockets.com/Rocket-Kits/Skill-Level-2-Model-Rocket-Kits/Aspire

29 mm, not 24.

 

[thzero]

Get the CTI 6G case!

Yeah I only found one long burn G which was from them. My sim without tracker or shock chord and not much in way of rentention said 1300 fps. That's with 4 fins, concincal nose cone, Estes bt50 body. So might be doable. At 4000' so is gonna drift quite a ways.

F44 only got to just over 1000 fps.

 

[user 35280]

29 mm, not 24

Use the 24mm adapter it comes with

 

[Starz]

By the way, how will you tell if your rocket breaks mach?

I will be using a Flightsketch mini in the AV bay.

 

[jqavins]

Use the 24mm adapter it comes with

Point taken. But the plan is a min diameter 24, and min diameter is indeed a good idea. (Apogee's recommended motor for supersonic flight is a 29 mm G.)

 

[PatD]

Cesaroni G145 6 grain 24mm. That should get you supersonic. Haven't simmed it, but maybe? Long burn is for altitude.

 

[thzero]

Cesaroni G145 6 grain 24mm. That should get you supersonic. Haven't simmed it, but maybe? Long burn is for altitude.

Point. Going to need an ejection altimeter though, since it doesn't have any ejection charge. But wildman does sell it (I just set the recovery to come out at apogee)





Just seems like this would totally shred the rocket.

 

[boatgeek]

Point. Going to need an ejection altimeter though, since it doesn't have any ejection charge. But wildman does sell it (I just set the recovery to come out at apogee)

View attachment 502471



Just seems like this would totally shred the rocket.

View attachment 502475

160+ G is pretty sporty... All of the 24mm 6G motors come with ejection charges, so you could use motor ejection and not an altimeter if you chose. What do the G65 white longburn and the G117 white get you in terms of speed? They would be a little less of a kick in the rear.

 

[user 35280]

Point taken. But the plan is a min diameter 24, and min diameter is indeed a good idea. (Apogee's recommended motor for supersonic flight is a 29 mm G.)

https://wildmanrocketry.com/collections/24mm-6-grain/products/pr24-6g-p

 

[dhbarr]

160+ G is pretty sporty... All of the 24mm 6G motors come with ejection charges, so you could use motor ejection and not an altimeter if you chose. What do the G65 white longburn and the G117 white get you in terms of speed? They would be a little less of a kick in the rear.

The g65 specifically almost never has enough delay for reasonable motor eject in a minimum diameter situation.

 

[PatD]

The G145, by your sim, puts you at mach 1.7, way past transonic. Airframe integrity may be an issue. I bought the 6 grain 24mm to use in a Mach1 BT60 Rim 66. Haven't had the urge to test it that way yet.

 

[Art Upton]

In about 1996 I had a 24mm G55 powered rocket design posted on Compuserve model.rockets for Mach busting.
Years later I found the Mach Buster being sold using not needed heavy phenolic tubing use that same motor.

I would try to find a G motor around the G55 spec if they make them, or a higher average thrust F.

I have flown many fire and if lost no regret rockets. At the price of the FS altimeter I would not cry except they are now back ordered due to supply chain issues. Ellis mountain made a 29mm I65 long burn motor. I flew that in an Estes Eliminator at LDRS 24. I lost it. Next day it showed up in the lost and found box.

Edit: I still have an AT G55 in my Stash Box.

 

[Art Upton]

The G145, by your sim, puts you at mach 1.7, way past transonic. Airframe integrity may be an issue. I bought the 6 grain 24mm to use in a Mach1 BT60 Rim 66. Haven't had the urge to test it that way yet.

Your talking fiberglass/carbon body at that speed, I still have a 24mm Mongoose I unboxed some years ago

 

[diyaerospace]

I will be using a Flightsketch mini in the AV bay.

Correct me if I'm wrong but I think that altimeter only goes up to 16 g. I'm pretty sure your rocket will easily pass that and that would result in the altimeter's speed readings becoming inaccurate. I have never used a Flightsketch altimeter before so take this with a grain of salt.

 

[jqavins]

I would try to find a G motor around the G55 spec if they make them, or a higher average thrust F.

From ThrustCurve.org, there are four current motors that more or less fit the above criteria:

• 24 mm
• G or not-too-low F total impulse
• 45 to 65 N average thrust

They are the CTI 60F50, 75F51, 144G65, and AT F51. They're all reloads. (Of those two F51s, the purple line is the AeroTech.)

 

[mrwalsh85]

All this talk about old school motors has me thinking I should try to break mach on a minimum diameter 18mm F55 motor

 

[jqavins]

ThrustCurve reports no 18 mm F engines, in production or not. Also no E engines. The best candidate in 18 mm would be the AT D21T. And even though ThrustCurve says it's in production, it doesn't seem to actually be available. (I think I have one.)

 

[mrwalsh85]

I have three AT F55's.

(3) Why Don't They Want Us Going Supersonic??? | Page 2 | The Rocketry Forum
(3) Jason's Motor Porn Thread | Page 12 | The Rocketry Forum
Rocket Basics (restorativland.org)

 

[dhbarr]

All this talk about old school motors has me thinking I should try to break mach on a minimum diameter 18mm F55 motor

Would certainly get the job done.

https://www.rocketryforum.com/threads/e45-f55-motor-details.135977/#post-1667261

; Aerotech F55 Data from data insert
F55 18 138 4-8-12 0.024000 0.034650 AT
0.025 88.846
0.05 89.295
0.075 89.744
0.1 89.744
0.15 90.641
0.2 91.090
0.25 91.987
0.3 91.090
0.35 90.192
0.4 89.295
0.45 85.256
0.5 76.282
0.525 67.308
0.55 53.846
0.575 40.385
0.6 26.923
0.625 22.436
0.65 17.949
0.675 13.462
0.7 9.423
0.725 8.974
0.75 7.179
0.775 5.385
0.8 4.487
0.825 4.038
0.85 2.692
0.875 0.897
0.9 0.000
;

 

[Starz]

Finished papering the fins today.

 

[Starz]

Glued on the fins using a 3d printed fin guide.

 

[diyaerospace]

Nice!
Do you plan on using epoxy clay fillets?

 

[Starz]

Nice!
Do you plan on using epoxy clay fillets?

No, I'm going to use Quick & Thick

 

[Initiator001]

ThrustCurve reports no 18 mm F engines, in production or not. Also no E engines. The best candidate in 18 mm would be the AT D21T. And even though ThrustCurve says it's in production, it doesn't seem to actually be available. (I think I have one.)

Somewhere on TRF is the story of how Scott Pearce and I came up with the 18mm E45/F55 and 24mm G42 motors.
The whole process was "Mostly Harmless".

In a minimum diameter/minimum mass rocket the E45/F55 could exceed Mach 1.
Our speed trials with these motors did not return usable data.
However, a rocket powered by a 18mm D21 motor was confirmed to pass the Speed of Sound (Mach 1.016).

 

[dhbarr]

Somewhere on TRF is the story of how Scott Pearce and I came up with the 18mm E45/F55 and 24mm G42 motors.
The whole process was "Mostly Harmless".

In a minimum diameter/minimum mass rocket the E45/F55 could exceed Mach 1.
Our speed trials with these motors did not return usable data.
However, a rocket powered by a 18mm D21 motor was confirmed to pass the Speed of Sound (Mach 1.016).

This does not surprise me at all.