Ressources for payload beginners

I'm starting my first payload project with a friend who is working in electrical engineering. He will build the electronic payloads and I will build the rockets from scratch.

We will be starting small in LPR with 10-30g of payload but we want to be able to send up to 100g of payload above 500m, which will require some MPR power. We will do a simple model with a small payload first to be able to launch this year and then get on the design board for a second design during the winter.

As the whole payload endeavor is completely new to me, I am looking for good sources of information about how to build a successful payloader. Do you have a books, web page or video to suggest that could be useful to get into payload launching?

Here is a list to which I will add your suggestions:

Books
- Handbook of Model Rocketry (Harry Stine)

Web pages

Videos
- Make a model rocket payload bay (Tim Van Milligan, Apogee Components)
- Mount an altimeter in a model rocket (Tim Van Milligan, Apogee Components)

Thanks in advance for your suggestions!

This is bigger then what you want, but lots of good info.

Small Satellites for Secondary Students..s$

https://s4.sonoma.edu/

Tony

Stine's book is good. You might also want to look at payload kits. https://www.jonrocket.com/index.php?main_page=index&cPath=1_39_49 has a fair assortment. If you haven't done much rocketry you may want to start with some kits to get your feet wet...


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Never did worry about the weight of what I was flying in my payloads (they were always small anyways).

Some MPR Estes kits you might look into cloning... The Maxi Icarus, and the Magnum. Gord (Sandman/Excelsiorrocketry.com) has decals for both. On my latest Magnum, I had him change the color from blue (which was impossible to match) to black. Looks pretty sharp. Clear payload sections can be made from using Lithonia Fluorescent Bulb Protectors (available at Home Depot (8' for~$5.00 USD)). Much cheaper than buying a kit or parts assortment for the 5" BT-60 clear tube. They are a little bigger than the standard BT-60 tube, so you'll need to add a step (I used a coffee stir stick) to the launch lug to keep it clear of the payload section, and some shims to hold the shoulders of the tube coupler and nose cone solidly in place.

Don't forget your passengers...

Can we get a definition of "Payload rocketry"? Is this a novelty off-shoot? A serious weight issue? Or a NAR-banned practice of orbiting insects and rodents?:wink:

One thing to consider based on what you put in the payload bay, is a good way to secure the NC. While friction fit will work, if your payload can move, it could actually pop the NC during the flight, losing both the NC and the payload. What I do, is drill a small hole through the BT into the base of the NC, and then use a small sheet metal screw to hold the NC on. By using a screw, you can open the bay up to insert or remove your payload, and the NC won't come off when you don't expect.

RecoRocket said:

One thing to consider based on what you put in the payload bay, is a good way to secure the NC. While friction fit will work, if your payload can move, it could actually pop the NC during the flight, losing both the NC and the payload. What I do, is drill a small hole through the BT into the base of the NC, and then use a small sheet metal screw to hold the NC on. By using a screw, you can open the bay up to insert or remove your payload, and the NC won't come off when you don't expect.

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I don't know if I will use this method but I am looking for a way to close the payload bay while minimizing the weight. I will try to avoid metal but only one screw isn't that bad.

Any suggestions?

morlock said:

I don't know if I will use this method but I am looking for a way to close the payload bay while minimizing the weight. I will try to avoid metal but only one screw isn't that bad.

Any suggestions?

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You could use a nylon screw. There is a concept in "dual deploy", where a shear pin in used for the laundry in the payload bay, where the shear pin stays in place until the ejection charge in the payload bay fires, and then the pin "gets sheared" and the NC comes out. a #2 nylon screw is common for this. Drill a hole thru the BT and NC base where you can insert the #2 screw, yet it's held in place (tight, but not too tight), Another option is using a "plastic rivet". You again drill a hole thru the two parts, and when ready to fly, you pop in the rivet, and push it home. To open things up, pop up the inside of the rivet to free it, and remove the rivet. Here's a thread right here about plastic rivets..

https://www.rocketryforum.com/showthread.php?832-Plastic-Rivets

If you go with a sheet metal screw, for a small diameter payload, you can get by with something like a #4x3/8", which is really small. I use #6 for birds up to 75mm AF.

If/when you start flying 29mm midpower, I'd consider an Estes Partizon (Seal off the upper third BT and set it up to split at the coupler), Argent, or Ventris. All will probably be on sale for labor day, and they could probably lift 100g to 500M, although you might want to look into getting level one cert for that. A high impulse G should work though, if you want to stay midpower.

Finally, if you dont want to use screws (which shouldn't add almost weight on a D-G impulse), masking tape around both the nose cone shoulder and a bit to hold the nose cone can work.

SCrocketfan said:

If/when you start flying 29mm midpower, I'd consider an Estes Partizon (Seal off the upper third BT and set it up to split at the coupler), Argent, or Ventris. All will probably be on sale for labor day, and they could probably lift 100g to 500M, although you might want to look into getting level one cert for that. A high impulse G should work though, if you want to stay midpower.

Finally, if you dont want to use screws (which shouldn't add almost weight on a D-G impulse), masking tape around both the nose cone shoulder and a bit to hold the nose cone can work.

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Using "mid power" and Estes in the same sentence makes me laugh, and makes my brain hurt! From all I've seen, they are just like Estes LPR, and cost twice as much as rockets designed for MPR-HPR. (with thicker tubes, CR's, etc) And as I said, friction fit for the NC MAY work, but at deployment, the NC may still be moving fast when the SC reaches it's limit. If you can remove a friction fit NC, an ejection charge surely can! In my BAR roctry days, I build a few Aerotech and NCR birds, and it didn't take me long to realized how bad they really were, and again, from what I've seen, the Estes MPR stuff is just as bad.

RecoRocket said:

Using "mid power" and Estes in the same sentence makes me laugh, and makes my brain hurt! From all I've seen, they are just like Estes LPR, and cost twice as much as rockets designed for MPR-HPR. (with thicker tubes, CR's, etc) And as I said, friction fit for the NC MAY work, but at deployment, the NC may still be moving fast when the SC reaches it's limit. If you can remove a friction fit NC, an ejection charge surely can! In my BAR roctry days, I build a few Aerotech and NCR birds, and it didn't take me long to realized how bad they really were, and again, from what I've seen, the Estes MPR stuff is just as bad.

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Any suggestions at all?

I will make suggestions. Ignore pistons, Estes (LPR) style MPR,, and look at vendors like PML and LOC. Both the PML IO and the LOC Little Nuke would make fine L1 birds that fly on motors from E-H, and don't include the nonsense like pistons! (my L1 was a PML IO about 15 years back). And if you ever get a kit with parts for a piston, take those parts and throw them in your parts box and forget about them. And maybe buy a 3x3 and 6x6 nomex chute protector next time you buy on line!

RecoRocket said:

I will make suggestions. Ignore pistons, Estes (LPR) style MPR,, and look at vendors like PML and LOC. Both the PML IO and the LOC Little Nuke would make fine L1 birds that fly on motors from E-H, and don't include the nonsense like pistons! (my L1 was a PML IO about 15 years back). And if you ever get a kit with parts for a piston, take those parts and throw them in your parts box and forget about them. And maybe buy a 3x3 and 6x6 nomex chute protector next time you buy on line!

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While I generally agree with you, don't dismiss the estes (and AT) MPR kits so easily. The Mega Red Max is just as tough as any MPR and people fly them up to baby I's. All the Estes MPR kits i've seen have tubing the same quality as any madcow kit, and the only thing remotely low power about them are the shock cord mounts. Sure you need a Nomex, but most rockets don't come with them anyway. Also, if you don't add the baffle/piston on aerotech kits (and swap motor retention) I see no reason why they aren't just as good as LOC/PML.

SCrocketfan said:

While I generally agree with you, don't dismiss the estes (and AT) MPR kits so easily. The Mega Red Max is just as tough as any MPR and people fly them up to baby I's. All the Estes MPR kits i've seen have tubing the same quality as any madcow kit, and the only thing remotely low power about them are the shock cord mounts. Sure you need a Nomex, but most rockets don't come with them anyway. Also, if you don't add the baffle/piston on aerotech kits (and swap motor retention) I see no reason why they aren't just as good as LOC/PML.

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When I started back in rockets about 20 years ago, I built a few AT kits, and in reality, they are a JOKE! The "dollar store" of MPR kits, but they were very costly for what you got, but out there in hobby stores..... If you're building At and Estes MPR, trust me, you don't learn how to build a real MPR or HPR bird....

BTW, I've seen an Estes Fatboy fly on an I - but it wasn't built per then parts and instructions that came with it! And if you don't understand the baffle/piston issues, please don't go for L1! And I can tell, you never built a Loc or PML bird.....

RecoRocket said:

When I started back in rockets about 20 years ago, I built a few AT kits, and in reality, they are a JOKE! The "dollar store" of MPR kits, but they were very costly for what you got, but out there in hobby stores..... If you're building At and Estes MPR, trust me, you don't learn how to build a real MPR or HPR bird....

BTW, I've seen an Estes Fatboy fly on an I - but it wasn't built per then parts and instructions that came with it! And if you don't understand the baffle/piston issues, please don't go for L1! And I can tell, you never built a Loc or PML bird.....

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Only AT kit I've built is the G-force and I've been very happy with it so far. I mean, it's not a fiberglass kit and it does use plastic fins, but it's just as durable as any conventional plywood component kit I've seen. I've built plenty of plywood MPR kits and use epoxy, and fully understand not to use baffles/pistons. While I haven't built a LOC or PML kit, i've built Madcow kits and I get that conventional HPR kits tend to be stronger than Estes/AT. Estes/AT can still be fine HPR though, and they could definitely work for what Morlock wants.

Morlock, for the smaller payloads, you might want to consider modifying a small egglofter rocket. They can easily lift 30 grams, and can hit ok altitudes with 24mm motors.

SCrocketfan said:

Morlock, for the smaller payloads, you might want to consider modifying a small egglofter rocket. They can easily lift 30 grams, and can hit ok altitudes with 24mm motors.

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I really want the payloader to be a scratch design. What I am looking for is good info on how to build a scratch payload bay that is closed on both sides, easily opened when needed and lightweight. I'm aiming for cardboard and balsa.

morlock said:

I really want the payloader to be a scratch design. What I am looking for is good info on how to build a scratch payload bay that is closed on both sides, easily opened when needed and lightweight. I'm aiming for cardboard and balsa.

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Look at the thread I started am an adding to about a scratch build bird with a 38mm AF and 29mm MMT. While I'm just starting the build thread there, it will show you techniques you'll never get from Estes or AT. It's kraft tube and plywood, will do about 1500 on an F40, and can be built for DD.... And coule fly a H128.....

https://www.rocketryforum.com/showt...ill-challenge-you-and-costs-30-in-basic-parts. It will show you how to build - not too strong, not too weak, but just right!

Yes, I did get my L3 over a decade ago, and now building stuff I can fly in a park without a waiver, but using the same techniques as in HPR..

SCrocketfan said:

Only AT kit I've built is the G-force and I've been very happy with it so far. I mean, it's not a fiberglass kit and it does use plastic fins, but it's just as durable as any conventional plywood component kit I've seen. I've built plenty of plywood MPR kits and use epoxy, and fully understand not to use baffles/pistons. While I haven't built a LOC or PML kit, i've built Madcow kits and I get that conventional HPR kits tend to be stronger than Estes/AT. Estes/AT can still be fine HPR though, and they could definitely work for what Morlock wants.

Morlock, for the smaller payloads, you might want to consider modifying a small egglofter rocket. They can easily lift 30 grams, and can hit ok altitudes with 24mm motors.

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FG is a sales/marketing issue. Even my L3 birds were built without glass. Unless you are passing Mach, FG is overkill, and even then, it depends on the design... Have you ever lanched a payload that was a 12 pack of beer? I have! It gave the recovery crew something to do coming back to the flight line after recovery!

I think we can help you out here. The majority of our projects are centered around complex payload scenarios that are both static and passive in nature as well as payloads that are released from the vehicle at apogee. We are currently designing a third generation vehicle that will be produced in low, mid and high power versions. At this time I am on vacation with limited internet access. If you would PM me your email we can send you our Rocksim files for our current design and the our future project. Until then some great resources are G. Harry Stine's Handbook of Model Rocketry chapter 15, Tim Van Milligan's book Model Rocket Design and Construction as well as NARs NARTS available on their website. NARTs are technical reports and there are several on payload design for competition. If there is interest here we will post some of our payload projects but these tend to be on the extreme "geek" side of the hobby.

Padseven said:

I think we can help you out here. The majority of our projects are centered around complex payload scenarios that are both static and passive in nature as well as payloads that are released from the vehicle at apogee. We are currently designing a third generation vehicle that will be produced in low, mid and high power versions. At this time I am on vacation with limited internet access. If you would PM me your email we can send you our Rocksim files for our current design and the our future project. Until then some great resources are G. Harry Stine's Handbook of Model Rocketry chapter 15, Tim Van Milligan's book Model Rocket Design and Construction as well as NARs NARTS available on their website. NARTs are technical reports and there are several on payload design for competition. If there is interest here we will post some of our payload projects but these tend to be on the extreme "geek" side of the hobby.

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Hi Padseven,

Thanks for the ressources. I think a lot of people are on the geek side of things here, so fire away and open a thread about your projects!

If you have direct links about some interesting specific NARTs, please post them. I'll try to go through them but after a first search on NARs website, I did not fine much.

I'll PM you about your design, but, once again, if it is not a secret, others would probably be happy if you posted them online and linked to them here!

so just for fun I did up an example design using Estes parts(aside from fins and a bulkhead), on an F52-8 the simulated altitude is 1600'. if you figure in paint, launch guides, and glue, that would drop the altitude to around 1500'. feel free to play around with the design.
Rex

View attachment eh_paylord.ork

the estes "mpr" birds seem to me no more than LPR rockets with larger tubes. NOT the proper way to learn MPR!

If Estes starts making 29mm motors with a rear thrust ring, I'll look again. But they wont - their 29MM motor retention is PLASTIC, right where the motor is so hot to melt it, and then there is the blow back from the blast deflector!

Estes is just trying to sell you before you get to the point you know it's crap!

Rex R said:

so just for fun I did up an example design using Estes parts(aside from fins and a bulkhead), on an F52-8 the simulated altitude is 1600'. if you figure in paint, launch guides, and glue, that would drop the altitude to around 1500'. feel free to play around with the design.
Rex

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Thanks for the .ork file!

Here is my ongoing design, a two stager using E motors. Simulation gives 760 m with booster (E12-0) and 480 m with first stage only (E9-6).

Should begin building this weekend and hope to fly it within a month and a half at an event 1h30 from where I live.

RecoRocket said:

the estes "mpr" birds seem to me no more than LPR rockets with larger tubes. NOT the proper way to learn MPR!

If Estes starts making 29mm motors with a rear thrust ring, I'll look again. But they wont - their 29MM motor retention is PLASTIC, right where the motor is so hot to melt it, and then there is the blow back from the blast deflector!

Estes is just trying to sell you before you get to the point you know it's crap!

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Hi RecoRocket,

Thanks for your input, but I guess Estes and LPR suites me fine for now.

Having fun is really my sole focus and going up the motor class ladder very gradually is how I plan to keep it fun for as long as possible

When I feel ready to graduate to bigger stuff, I'll be sure to do it, but that won't be for this year. Maybe next year I'll step into the F and G motor arena. Until them, it is Quest, Estes or scratch builds, up to a maximum of 2.6 inches and with cardboard, plastic and balsa.

nothing wrong with taking the time to enjoy the journey. Estes did their homework when they were designing the Pro series II birds. they do have heavier/thicker walls on the tubes, and they can be flown on motors as large as an I200 (built stock, complete with the oversize tri-fold shock cord mount). motor cases are not supposed to get over 400F.
Rex

RecoRocket said:

the estes "mpr" birds seem to me no more than LPR rockets with larger tubes. NOT the proper way to learn MPR!

If Estes starts making 29mm motors with a rear thrust ring, I'll look again. But they wont - their 29MM motor retention is PLASTIC, right where the motor is so hot to melt it, and then there is the blow back from the blast deflector!

Estes is just trying to sell you before you get to the point you know it's crap!

Click to expand...

++ What Rex said.

I don't know what you consider "If Estes starts making 29mm motors with a rear thrust ring" but they do have their own brand of motors made for them by another manufacture. That happens to be Aerotech. Those are quality motors and they do have rear thrust rings.

As far as the motor retention, I've got no problem with that either. Have you ever seen one melted? They have worked just fine on my Leviathan with everything from SU G80s to RMS H250Gs. It doesn't even have burn marks, much less melting, just a little soot. I'm adding the Estes retainers to other 29mm HPR rockets I'm building. They are cheap and light and work just fine.

I know some folks can't resist Estes bashing, but the Pro II series are not bad kits. They may not be the highest quality, but for the price, if you can follow the assembly directions, they work well, fly fine, and last long time. There are worse kits out there.

I have 4 of the Estes Pro Series kits. Built 2 of them completely stock using wood glue. I've only flown one of them on a G using a reloadable case. No damage at all to the retainer. I loaded a 29mm H in a reloadable case but the motor spit the starter out and the waiver window closed before I could try again. But I have every confidence that a stock built Pro Series rocket is tough enough to do a level 1 on. With the kits on sale, anyone who thinks high power certification is too expensive could get a level 1 very inexpensively. Of course it then gets expensive after you get the cert because the motors get expensive.

Joe


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Jmhepworth said:

I have 4 of the Estes Pro Series kits. Built 2 of them completely stock using wood glue. I've only flown one of them on a G using a reloadable case. No damage at all to the retainer. I loaded a 29mm H in a reloadable case but the motor spit the starter out and the waiver window closed before I could try again. But I have every confidence that a stock built Pro Series rocket is tough enough to do a level 1 on. With the kits on sale, anyone who thinks high power certification is too expensive could get a level 1 very inexpensively. Of course it then gets expensive after you get the cert because the motors get expensive.

Joe


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Click to expand...

One good flight on a G (which G?) could just be luck, and not a real review. Even within a "class" of motors, some are designed for higher thrust, and some for a longer burn. As far as costs, both LOC and PML have had kits in the same price range for many years that could be used for L1. (I got my L1 on one of them back in the 90's). Madcow also has kits in the same price range today that could be flown for a L1.

This is actually Estes' second dance with MPR. In the 90's they bought out NCR (North Coast Rocketry) for MPR stuff. But NCR has this non-standard 28mm MMT, that wouldn't take the (even then standard) 29mm motors, and NCR products vanished due to bad press....

Any MPR that used a three folds paper system to attach the SC would worry me. Tell me Estes doesn't use elastic SCs in these kits! (even on LPR stuff from Estes, I use something else for the SC.)

And BTW, I know people that flew L2 with a bird built with wood glue. Once you get used to using epoxy, you might find it easier to use. For example, it will flow a bit more than wood glue, giving you more contact with things like the outside fillets on a TTW fin build. The glue only needs to be stronger than the parts it's attaching!

morlock, I've had a chance to glance at your design...looks like it should work but, you're going to need a bigger chute. descent rates tend to be more than a bit flaky to guestimate as you get under 10" and your rocket will quite likely crumple coming in that fast. I would suggest a 12" chute at a minimum.
Rex

Thank you Rex, I was hoping you would have a look

I made the chute that small so that the plot of the flight looks good. I mean, that the upwards part is not compressed in a tiny portion of the graph to the left. I will take your advice on the chute size.

Do you know how we can tell OR to plot only the first x seconds without having to export the files and do the plot in excel or open office?