Need Help Exceeding Mach 1

I am a senior in high school and I am in the second tier of the SystemsGo rocket program. Last year, our class was responsible for sending a rocket with a one pound payload, one mile high. This year, our class has to design a rocket to break the sound barrier with a 3 mile ceiling.
While I have a decent amount of rocket knowledge, I would consider myself an amateur still. I've had several experiences with low power model rockets and last year was my first experience with a mid power rocket.

My teacher is a "figure it out yourself" kind of guy, and I'm searching for someone to at least point me in the right direction. I am a hard worker and very interested in this topic, I just need to know where to begin. If anyone has any resources or links they could show me, that would be great. Otherwise, it would help out if someone could answer a couple of the following questions:

What are the biggest/most difficult challenges in the design of a transonic build?

What would be the best method of tackling this task? In other words, what materials and specifications would be most practical for this kind of flight?

Where is a good link to learn the ins and outs of RockSim?

If there is any other advice or lessons that you would like to give me, I'm all ears. This is my first time on this site and I am hoping it is a supporting community. Thanks!

This is a great community an you should get lots of help.

If you don't already have RockSim I suggest you download OpenRocket. It is a similar program and is free. Its been a while sine I have used either, so I can't be of much help. But I remember that OpenRocket was fairly easy to use.

Do you have any rocket clubs near you? That would be a great place to start as you will need a good field to launch and recover at. More than likely there will be people who have exceeded Mach 1 in the club too. I assume you have to prove you went supersonic, so do you have electronics to do that?

Our class already has RockSim, and being an extensive program with a transonic rocket, I am assuming I will have to learn various complexities such as mass overrides. I was just wondering if anyone knew the best place to get tutorials for this program that exceeds the basics.

I live in Texas, and the closest rocket club to me would be in Houston, which is over an hour away. I am trying to learn as much as I can from the community if it would save the trip out there. However, I know they would be a great resource and would be a lot of help.

As for electronics, we have not began our construction yet, and we are only in the research phase. Last year we used the Stratologger CF as an altimeter and felt pretty comfortable using it. This year we have researched into using a backup altimeter. If one of these altimeters is not capable of GPS, we also need a way to have some sort of tracking system.

I think most OR and RS users will tell you to use OR for transonic and supersonic simulations. As Zeus-cat recommended I would grab OR https://openrocket.sourceforge.net/download.html and just start playing with some designs and simulations. If you are not aware, depending on where you are located you will require some form of certification for use of a high power motor as well as a designated launch site. I am betting there are many on this forum who will help out and have likely been involved in this type of challenge before so you hit the right place.

One thing you may want to factor into your design, if not already, would be some form of tracking as flights that hit this velocity can be challenging to visually track and sometimes you just lose sight of them and never pick them up again, so a tracker will help.

Good luck, you should have no problem doing this within a 3 mile ceiling.

Fontastic said:

Our class already has RockSim, and being an extensive program with a transonic rocket, I am assuming I will have to learn various complexities such as mass overrides. I was just wondering if anyone knew the best place to get tutorials for this program that exceeds the basics.

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Looks like we posted at the same time. The forum has a section for software and there are many threads on both RS and OR https://www.rocketryforum.com/forumdisplay.php?36-Rocketry-Electronics-and-Software

Fontastic said:

If one of these altimeters is not capable of GPS, we also need a way to have some sort of tracking system.

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Check out eggtimer rocketry

Fontastic, please also keep us posted as you progress!

I guess more knowledgeable people will answer but it kind of sounds like the design you are after is a minimum diameter (potentially 38mm) rocket that is elongated (lenght maybe 12+ times the tube diameter) that has been reinforced with carbon fiber. Have you ever played with fiberglass or carbon fiber and epoxy? (I myself haven't yet).

The rocket will probably require more than a G class motor (I may be wrong), so you may need to have someone wiyh a L1 certification either in your group or someone that agrees to launch your rocket.

First off, get an altimeter with an accelerometer. It's a more accurate way to measure speed than barometric only altimeters. When selecting an altimeter, pay attention to the G forces it's designed to handle. My last mach flight simmed to 44G. It peg'd out the 50G accel. opps. lesson learned.


Secondly, what size motor are you looking to fly, and what size rocket?

morlock said:

Fontastic, please also keep us posted as you progress!

I guess more knowledgeable people will answer but it kind of sounds like the design you are after is a minimum diameter (potentially 38mm) rocket that is elongated (lenght maybe 12+ times the tube diameter) that has been reinforced with carbon fiber. Have you ever played with fiberglass or carbon fiber and epoxy? (I myself haven't yet).

The rocket will probably require more than a G class motor (I may be wrong), so you may need to have someone wiyh a L1 certification either in your group or someone that agrees to launch your rocket.

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Fitting redundant systems into a 38mm MD along with a tracker is a challenge for most but MD is the way to go if you want to keep the motor class down. I cannot find the rules on the "find someone to launch your rocket" but it is ringing a bell for me so there may be an issue with it, having said that their may be exceptions in the case of group education projects?

I think finding a local club early is a good idea as that will dictate the rules and regulations you will have to follow.

Fontastic said:

I live in Texas, and the closest rocket club to me would be in Houston, which is over an hour away. I am trying to learn as much as I can from the community if it would save the trip out there. However, I know they would be a great resource and would be a lot of help.

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The Tripoli Houston guys are a great bunch and I would say that it would definitely be worth your time to spend a Saturday morning visiting one of their launches. You can find other launches in the south Texas area here:

https://www.artapplewhite.com/launches.html

Maybe one of the fields is even closer.

Our teacher is a has an L1 certification, and we are designated to launch with a program called SystemsGo, which sponsors their program to be "taught" in schools. Basically, our schools are entered into this launch and our teachers have the freedom to choose how to teach us. And mine offers little guidance, with the reasoning that we learn better if we figure it out by ourselves. I personally disagree with this mentality, however, I am looking to do what it takes in order to be successful.

If OpenRocket is a better program for transonic and supersonic flights, I will be more than willing to try it out. Thanks with the pointer towards the software threads and also the eggtimer rocketry.

We figured we would need to go with a smaller diameter, and after research we knew we needed carbon fiber or fiberglass or reinforcements by either of the two. We have never played with carbon fiber nor fiberglass, but have experience with epoxies.

With a 38 mm body tube, how much complications arise with the tightness of space when it comes to an avionics bay or packing parachutes? Last year our body tube was 98 mm so we had plenty of room.

Even in a 38mm Min Diameter rocket, you are going to need a Level 2 motor most likely a 38mm K motor like the Loki K1127-LB to get it to 15840' AGL (Thats what my Weasel 38mm MD sims close to with that motor). J class Mello Yellows only get about 13k.

38mm is tight but doable and you'll break Mach on a decent sized I motor. Here's a pic of my nose cone av bay. I used a cable cutter to do dual deploy but you don't have to add that complexity, you could just make the rocket long enough for a conventional dual deploy setup and still break mach without much trouble.

On one side is a stratologger and 2x lipo batteries. On the other side of the av bay is an eggfinder gps (definitely recommend you have tracking).

Aerotech I600R will get a 38 MD cleanly over M1.

FG will be heavier than cardboard, but can do the job easily. Thin-wall fiberglass will help keep the weight down. Carbon fiber isn't needed, but will work quite well.

Complications? just less space. using lipo batteries will help here.

That is a clever avionics system, but was there any difficulty in packing parachutes in such a tight space? and the goal for our class is to break the sound barrier while staying under a 3 mile ceiling. The size of the motor is not as much of an issue as getting the right amount of velocity quickly so the rocket will not coast over our ceiling.

As long as you make the main body long enough you'll have no issues packing an appropriately sized chute in there - I used an 18" main.

What were the specs and results of your rocket Zebedee?

Yes this task is very achievable with a 38mm minimum diameter.

Fontastic said:

Our teacher is a has an L1 certification, and we are designated to launch with a program called SystemsGo, which sponsors their program to be "taught" in schools. Basically, our schools are entered into this launch and our teachers have the freedom to choose how to teach us. And mine offers little guidance, with the reasoning that we learn better if we figure it out by ourselves. I personally disagree with this mentality, however, I am looking to do what it takes in order to be successful.

If OpenRocket is a better program for transonic and supersonic flights, I will be more than willing to try it out. Thanks with the pointer towards the software threads and also the eggtimer rocketry.

We figured we would need to go with a smaller diameter, and after research we knew we needed carbon fiber or fiberglass or reinforcements by either of the two. We have never played with carbon fiber nor fiberglass, but have experience with epoxies.

With a 38 mm body tube, how much complications arise with the tightness of space when it comes to an avionics bay or packing parachutes? Last year our body tube was 98 mm so we had plenty of room.

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38 mm MD is tight but doable. Having redundant altimeters may be a challenge, depending on how you mount them, but again something you will likely get around this if you need or want to. There are some 38mm G, H and I motors to use so an L1 may suffice but an L2 would give you a fuller range. You should just start playing with some sims and see what works for you.

As far as materials, at that velocity you could easily stick with a thin wall FW/FG, no need for CF, if you want to save some money. You could also likely get away with just surface mounted G10 plate fins with fillets and skip a tip to tip reinforcement, so the project should be relatively easy for a MD project.

I attached an Openrocket file that is very rough but should help you get the idea. I would recommend using a 36inch fiberglass booster with a nosecone of you choice.

View attachment 38mm.ork

Thanks for the advice and support. I will do some playing around with both RockSim and OpenRocket and see what problems I run into.

Yea, access to an L2 would make this "easy". I put my 2.6"/ 38mm motor mount Screech up 4 times to mach this summer. TONS of fun

I'll skip posting 100 photos here (for once), but here's a link to them

https://www.flickr.com/photos/31757945@N05/sets/72157652603347240

Cool project! I'm a high school teacher, and I'm actually looking into starting a program at my school this spring... I'm subscribed. Curious to see how you get from here to Mach! This is a great place to ask questions, but remember, there's a thousand ways to crack a nut. Here on TRF, you will be offered 3000 methods of cracking said nut... ;-)

DizWolf, our teacher might be L2 certified as we bought a J330 engine last year. What specs did you use to build your Screech?

I misread the OP as breaking Mach and over 3 miles, not read as breaking Mach and not exceeding 15840'. Like Diz says a 38mm MD will easily do Mach 1 and well under 3 miles altitude.

Nothing crazy for the Screech. It's a Madcow 2.6" Thin-Wall Fiberglass Dual Deploy Screech. I did the recovery harness to the MMT with JB weld, as well as the motor retention. The rings, mount and fins were installed with Aeropoxy ES6209. Fillets were proline 4500, drawn out with a 3/4" pipe.

4 foot rocketman chute. MARSA54L altimeter. BRB900 tracker. I flew it on an aerotech J510W, a Loki J1026 LC, and a pair of Loki K1127 Loki blue. (aerotech 38/1320 case, Loki 38/1200)

photos- https://www.flickr.com/photos/31757945@N05/albums/72157647408994783

thread- https://www.rocketryforum.com/showthread.php?123054-Madcow-2-6-quot-FG-Screech&highlight=screech

[youtube]2LlFECiy5oc[/youtube]
[youtube]bVJD1Akxh-U[/youtube]


you can see in the one photo, I roasted the rear end. I coated it in JB weld after the first two flights. Seems to be holding up. If I did this again, I would stick the rear of the motor further out. I'd also considering knocking it out to a 54mm motor mount. (and if you want 54 MD, the Tomach is aptly named for this- https://www.madcowrocketry.com/54mm-fiberglass-tomach/ I'm building one of those now. https://www.rocketryforum.com/showthread.php?128594-Madcow-54mm-Tomach-(4500-fillets))

Anything wrong with going smaller? An Apogee Aspire with an Aerotech H115 DMS? That stays within L1.

Well, other than the 50G accereration and the difficulty of recovery?

Aerotech 18 mm D21 motors will easily break Mach 1 in a MD rocket.

I just spent awhile cruising the class website [or one of several] and the Facebook page showing trip to White Sands by Fredricksburg school. Quite impressive.
https://www.systemsgo.org/

I believe you are in the Oberth section of studies at the moment:

Oberth Level : The intermediate stage, named after the German physicist Hermann Oberth, gives students the goal of designing and launching a rocket able to reach transonic velocity while maintaining a maximum altitude of less than 13,000 feet. This project is completed over the Spring semester with launches held in Fredericksburg, Texas.

I get what's expected of you guys now.
They want you to take the time & learn "how" to design a rocket in simulators first....to meet specific parameters. Then build the proof of concept.
In about an hour I ran many solutions to your project. You can build them in just about any size from 38mm -54mm -2.6 in -3in.- 4in. even 5in diameter rocket to hit mach 1 and stay under 13,000 ft. I did a 4in. diam. easily hitting requirements on a 54 motor, among the many sizes.

In your case I would stick with something easy to work on prepping & flying at LEAST 54mm diam.where you have some room. After a few sessions on Open R or Rocksim, just use some imported files to change and learn on, then build some of your own designs.

You will find it is quite simple to design, then fly on multitude of motors to stay within the bounds of Oberth. Keep it simple and standard, nothing fancy to guarantee success on your first time out.

Do you have funding available ....anyhow depending on your budget constraints...that will be key in size and design.

Contact me off list [PM] if you want some personal guidance from someone who's been there.

You should be able to do this without going to fiberglass or minimum diameter. The Cesaroni I540 and Aerotech I600 motors should be a big help, keeping it at basic certification too.

Fontastic said:

I am a senior in high school and I am in the second tier of the SystemsGo rocket program. Last year, our class was responsible for sending a rocket with a one pound payload, one mile high. This year, our class has to design a rocket to break the sound barrier with a 3 mile ceiling.
While I have a decent amount of rocket knowledge, I would consider myself an amateur still. I've had several experiences with low power model rockets and last year was my first experience with a mid power rocket.

My teacher is a "figure it out yourself" kind of guy, and I'm searching for someone to at least point me in the right direction. I am a hard worker and very interested in this topic, I just need to know where to begin. If anyone has any resources or links they could show me, that would be great. Otherwise, it would help out if someone could answer a couple of the following questions:

What are the biggest/most difficult challenges in the design of a transonic build?

What would be the best method of tackling this task? In other words, what materials and specifications would be most practical for this kind of flight?

Where is a good link to learn the ins and outs of RockSim?

If there is any other advice or lessons that you would like to give me, I'm all ears. This is my first time on this site and I am hoping it is a supporting community. Thanks!

Click to expand...

Fontastic, where specifically are you? I'm in Katy, and could walk you through pretty much everything that you need to know. There's also a metric shedload of Houston based resources on the NW and SE side of Houston. Hell, if you're nearby I could teach you how to glass and even help you make fiberglass tubing from scratch if you were interested. For reference, check out the FlyingMooMoo build thread in the High Power forum. Everyone at Tripoli Houston is really nice, it's half the reason I joined with them.