My Road to LDRS 34

[codysmith]

I think your wooden retainer can work just fine. Just sand it well and put a good thick coat of paint on it.

Using non-rocketry tubes to build rockets can work just fine, but I've had some issues with them. The first ones I used were heavy 1/8" thick wall tubes (2" ID, 2.25" OD) I build my L1 cert rocket out of. It was DD and flew a couple times on AT I1299N-P Warp9 motors where it pulled 80+ Gs. and did just fine. Others I built from thin wall mailing tubes and they didn't do as well. They held up to the motor thrust fine, but landings tended to cause them to split and bend. One rocket only lasted 3 flights before the landings totaled the BT. Non-rocketry tubes are built with much less compression so the walls are softer and more pliable.

My recommendation is to put a thin coat of glass on any thin wall non-rocketry tubing you use for a BT. Also, spray a heavy coat of paint on the inside to keep the ejection gases from causing issues since these aren't usually finished as well as the rocketry tubes are. Just be careful of spraying paint down the tube if you used a standard MMT. The motor won't want to fit if you get too much paint in there.

Good Luck and look me up at LDRS34

Will do. Thanks for the tip. These tubes are thick walled so I think they will be fine but I might paint the inside as suggested. These won't be flying on Warp 9's so I'm not very worried.

 

[conman13]

Will do. Thanks for the tip. These tubes are thick walled so I think they will be fine but I might paint the inside as suggested. These won't be flying on Warp 9's so I'm not very worried.

You could do give it a thin coat of epoxy if you wanted to keep the "wood" look.

 

[codysmith]

To get things going again, I want to put up the openrocket for my minimum diameter rocket. I can't upload any files now. Grrrrrrrrr:gavel::gavel::gavel::caffeine:. So, they will be up hopefully in the AM. Right now, I am just going to kind of explain it.

First off, nothing has been bought yet and nothing will be for a while.

I would like your help in design as this is my first MD. The plan right now, is (from top to bottom) a PML Urethane NC. This sounds like a good low-cost way to do Mach. Next is a Small section of Body tube ( Glassed Phenolic) that is used as part of my AV bay. That airframe is connected with a coupler to the lower airframe. Fins are fiberglassed 1/8" plywood.

Electronics: RRC2+ for Deployment ( drougeless with a streamer at 500'. Single separation. Deployment of the streamer will be with a cable cutter.) and an eggfinder for tracking.

I think it will be less complicated once you can see what I'm talking about..

 

[T34zac]

I would like your help in design as this is my first MD.

Glad to help. I can share some of the things I learned with my MD.

The plan right now, is (from top to bottom) a PML Urethane NC.

From what others have told me it's a good nose cone. However, it's solid, you can't put anything inside it. Use wood if you can, then hollow it out a little bit to fit some electronics on the inside.

Next is a Small section of Body tube ( Glassed Phenolic) that is used as part of my AV bay.

If your doing 38 or 29mm MD, regular phenolic is good enough. No need to waste the money on glassed phenolic. If you put a J on it however...

Fins are fiberglassed 1/8" plywood.

PML makes custom G10 fins in 1/16" 3/32" and 1/8". Make the design for the fins and include all the dimensions, send it to the PML sales department (make sure to specify the thickness as 0.062", 1/16"). It will only cost about $10-$15. It will be lighter and stronger than the plywood.

Electronics: RRC2+ for Deployment ( drougeless with a streamer at 500'. Single separation. Deployment of the streamer will be with a cable cutter.) and an eggfinder for tracking.

Good choice, make sure your static hole is large enough.

I think it will be less complicated once you can see what I'm talking about..

Can't wait to see it

 

[codysmith]

Wow! Thanks for the help! Maybe I will do the PML fins. Do you think I need to do T2T? It's expected to go right around M2 and 8,100 ft.

 

[T34zac]

Wow! Thanks for the help! Maybe I will do the PML fins. Do you think I need to do T2T? It's expected to go right around M2 and 8,100 ft.

What motor gets you Mach 2?

 

[codysmith]

What motor gets you Mach 2?

I600

 

[T34zac]

I600

That's interesting. My min diameter was optimized to fly as high as possible on an I motor (I216). It simmed out to around 12.4k and Mach 1.6. With an I800 I only hit Mach 1.4. I would very much like to see your design...

 

[codysmith]

I will put the sims up tomorrow. I'm interested to see what's going on.

 

[T34zac]

I will put the sims up tomorrow. I'm interested to see what's going on.

As am I. I'm no expert on T2T, so I don't know if you need it for a Mach 2 flight on G10. But my guess would be that your not going to hit Mach 2. I would also guess that you would go higher with that kind of speed, I don't think it's that easy to stay under 10k at M2

 

[T34zac]

I just did the sims with my rocket, the I600 brings my rocket to M1.6. It is heavier and longer than I would like it to be. If your rocket weights less (aprox. 14grams), it is possible that you could hit M2.

 

[codysmith]

Well, here is the simView attachment Drag Racer.rkt. I don't see anything really wrong but I'd apreciate some advice. I know this won't hit M2, but it should be close.

 

[codysmith]

I'm trying to decide if I want to use phenolic or blue tube. Any thoughts? What do you think about recovery? Drougeless with a streamer?

 

[T34zac]

I'm trying to decide if I want to use phenolic or blue tube. Any thoughts? What do you think about recovery? Drougeless with a streamer?

I'm using drogueless with a 24" parachute. I like phenolic. Especially if your ordering PML g10 fins, then you can do it all in one order.

 

[codysmith]

I'm using drogueless with a 24" parachute. I like phenolic. Especially if your ordering PML g10 fins, then you can do it all in one order.

Good point...

 

[codysmith]

View attachment Drag Race Modified.rkt Here is the updated OR file. I changed the fins to 1/16" G10 and a Semroc balsa nose cone. I think it is still in inventory but I'll call/email first. Inside the NC I got it hollowed out to accept a BT-50 for the eggtimer. In front of the BT-50 there will be a BT-20 tube for a little extra space for antenna's and stuff like that. With a bulkhead to cap it off. I'm also extending the BT by 2 inches to make more room for recovery equipment. With a 24" chute and shock cord, I figured I'd better be safe than sorry.

For SC, I think I am going to get the same stuff conman13 got for his Aurora. I found it on ebay and I like the price! For Parachute. I think I am going to either 1) Make a really strong homemade chute or 2) reinforce one of my PSII chutes. I like topflite, but Unless I get more money, it's going to be a crunch.

With all the new stuff I'm doing, I really need you to check my sim because it is now showing 9800 ft and M2.19 on the I600.

I'm Trying to think of a cool name but I guess I still have time.
Thanks for hanging in there with me!

 

[conman13]

View attachment 183735 Here is the updated OR file. I changed the fins to 1/16" G10 and a Semroc balsa nose cone. I think it is still in inventory but I'll call/email first. Inside the NC I got it hollowed out to accept a BT-50 for the eggtimer. In front of the BT-50 there will be a BT-20 tube for a little extra space for antenna's and stuff like that. With a bulkhead to cap it off. I'm also extending the BT by 2 inches to make more room for recovery equipment. With a 24" chute and shock cord, I figured I'd better be safe than sorry.

For SC, I think I am going to get the same stuff conman13 got for his Aurora. I found it on ebay and I like the price! For Parachute. I think I am going to either 1) Make a really strong homemade chute or 2) reinforce one of my PSII chutes. I like topflite, but Unless I get more money, it's going to be a crunch.

With all the new stuff I'm doing, I really need you to check my sim because it is now showing 9800 ft and M2.19 on the I600.

I'm Trying to think of a cool name but I guess I still have time.
Thanks for hanging in there with me!

Cody I will send you some of the sc I have. How much do you need? You may want to change the motor to get the velocity down.

 

[codysmith]

Cody I will send you some of the sc I have. How much do you need? You may want to change the motor to get the velocity down.

Cool! I think I will need about 10-15 feet. I don't want it too long for space reasons but I don't want it to be too short. What motor would I change it to?

 

[T34zac]

View attachment 183735 Here is the updated OR file. I changed the fins to 1/16" G10 and a Semroc balsa nose cone. I think it is still in inventory but I'll call/email first. Inside the NC I got it hollowed out to accept a BT-50 for the eggtimer. In front of the BT-50 there will be a BT-20 tube for a little extra space for antenna's and stuff like that. With a bulkhead to cap it off. I'm also extending the BT by 2 inches to make more room for recovery equipment. With a 24" chute and shock cord, I figured I'd better be safe than sorry.

For SC, I think I am going to get the same stuff conman13 got for his Aurora. I found it on ebay and I like the price! For Parachute. I think I am going to either 1) Make a really strong homemade chute or 2) reinforce one of my PSII chutes. I like topflite, but Unless I get more money, it's going to be a crunch.

With all the new stuff I'm doing, I really need you to check my sim because it is now showing 9800 ft and M2.19 on the I600.

I'm Trying to think of a cool name but I guess I still have time.
Thanks for hanging in there with me!

Sorry this took so long. I just looked at your file in OR and immediately noticed something wrong. There is no way you will hollow out a balsa NC that much. Your body tube will end up longer than your original plan so you can accommodate the length of the electronics. Also, your av-bay will probably be heavier than originally thought as well.

Like I said earlier, this was just a quick look. I will look at it later today when I have time.

 

[codysmith]

Sorry this took so long. I just looked at your file in OR and immediately noticed something wrong. There is no way you will hollow out a balsa NC that much. Your body tube will end up longer than your original plan so you can accommodate the length of the electronics. Also, your av-bay will probably be heavier than originally thought as well.

Like I said earlier, this was just a quick look. I will look at it later today when I have time.

Alright thanks, should I try to fit a tracker in the NC still?Or could I possibly just make the NC the Av Bay extension? (I.e, Hollow out the NC only a few inches and cut a sled to shape that will fit from the tube to the NC?) I'll try to put it into OR.

EDIT: I put it into OR. If I put a 3 inch hole in the NC and lengthen the AV bay by 1 inch, it gives me 9 inches of space for electronics. That should be fine i think.View attachment Drag Racer(2).rkt

 

[T34zac]

Alright thanks, should I try to fit a tracker in the NC still?Or could I possibly just make the NC the Av Bay extension? (I.e, Hollow out the NC only a few inches and cut a sled to shape that will fit from the tube to the NC?) I'll try to put it into OR.

I hollowed out my NC about 1.75-2" (my shoulder was 1.5"). That's where my tracker goes, I friction fit it in there as it's in a plastic case (will post a pic when I can). I have no experience with an eggfinder (or is it eggtimer?) so I don't know if it needs a sled or not. Then the sled is just a small strip of wood to fit the altimeter and battery.

 

[codysmith]

I hollowed out my NC about 1.75-2" (my shoulder was 1.5"). That's where my tracker goes, I friction fit it in there as it's in a plastic case (will post a pic when I can). I have no experience with an eggfinder (or is it eggtimer?) so I don't know if it needs a sled or not. Then the sled is just a small strip of wood to fit the altimeter and battery.

Sounds good. Eggtime rocketry makes both the eggtimer ( dual deploy altimeter) and the eggfinder ( tracker). I will be using a RRC2+ for altimeter so I just need the eggfinder. I don't know if it has a case. Connor?

 

[conman13]

No case it could be friction fit in the nosecone with bubble wrap. Depending on which antenna you go with(wire or rubber duckie) you should be fine with the space you have.

 

[codysmith]

Alright, sounds good. Quick question about ejection charges. I want something simple, so I was wondering if a set up like this is okay. This is with the carraige bolt as the all thread/eyebolt whatever. Wire goes from the altimeter through two holes in the bulk plate. this wire can then be twisted and isolated (as shown) to the igniter. I would then seal the AV bay with a silicone or hot glue. Would this set up work? Also, I will ground test it, but do you think the igniter shown would work? They are for motors but Look like they could work. I think they are the same as these. https://www.amazon.com/Electric-Igniter-Fireworks-Pyrotechnics-Survival/dp/B00J4C0028

 

[T34zac]

Alright, sounds good. Quick question about ejection charges. I want something simple, so I was wondering if a set up like this is okay. This is with the carraige bolt as the all thread/eyebolt whatever. Wire goes from the altimeter through two holes in the bulk plate. this wire can then be twisted and isolated (as shown) to the igniter. I would then seal the AV bay with a silicone or hot glue. Would this set up work? Also, I will ground test it, but do you think the igniter shown would work? They are for motors but Look like they could work. I think they are the same as these. https://www.amazon.com/Electric-Igniter-Fireworks-Pyrotechnics-Survival/dp/B00J4C0028View attachment 183745View attachment 183746View attachment 183747

That setup would work just fine. However, I would put both igniter leads through the same hole for simplicity's sake. You can even put the cable cutter leads through the same hole, just don't get them mixed up.

That igniter you have should work just fine. ALWAYS GROUND TEST FIRST. You don't want to be caught in the air with a questionable igniter.

 

[codysmith]

That setup would work just fine. However, I would put both igniter leads through the same hole for simplicity's sake. You can even put the cable cutter leads through the same hole, just don't get them mixed up.

That igniter you have should work just fine. ALWAYS GROUND TEST FIRST. You don't want to be caught in the air with a questionable igniter.

Alright, Thanks for the Confirmation. I think since I have two holes, I will do one hole for ematch leads, and the other for Cable cutter leads.

 

[T34zac]

Alright, Thanks for the Confirmation. I think since I have two holes, I will do one hole for ematch leads, and the other for Cable cutter leads.

That's fine, as long as you seal your av-bay from ejection gasses.

 

[codysmith]

I just realized I really don't need the wire from the altimeter to the igniter leads. It just adds another potential failure point. Instead, I can just plug my (long) igniter leads into the altimeter.

 

[T34zac]

I just realized I really don't need the wire from the altimeter to the igniter leads. It just adds another potential failure point. Instead, I can just plug my (long) igniter leads into the altimeter.

Exactly what I do. I just shorten the igniter

 

[T34zac]

I just got back to looking at your design file and I have a few questions.

What are you using for a shock cord? And how long?

What type of battery are you using?

Is you NC hollow?

How do you plan on setting up the Av-bay?

Motor retention?

What size casing?

Plugged motor?

Also, another thing to consider is the length that the parachute takes up. My parachute is also a 24" (top flight). With the appropriate sized Nomex, my parachute takes up 5.5" of my airframe. Then you have to add room for the shock cord, room for the streamer, and room for the coupler to slide into this tube (PML phenolic couplers are 3" long).

Your electronics with sled most likely won't weigh 1oz. It will probably take up more than 4.7" as well. My electronics bay is 7". That accommodates for a larger RRC3 altimeter, 7.4v li-po for the RRC3, and tracker (with coin cell battery). So your Av-bay will most likely be 5.3" depending on the length of you tracker and the batteries for your electronics. I don't know what batteries you plan to use, nor do I know what the length of the eggfinder is. So that 5.3" assumption is based off my setup.