How long does it take to prep a reload?

[neil_w]

I've only used BP and single-use composite motors so far, and to be honest have no real interest in doing reloads. But I am really curious about long it takes to prep a motor, once you know what you're doing. How long does it take you to prep a single motor? Do you ever do them at the field, or only at home in advance?

As I said, I am just curious.

 

[H_Rocket]

With the exception of a large motor that requires grain bonding, I can do most non-CTI reloads in under 5 minutes. CTI < 75mm under two minutes. CTI 75mm - about 5 minutes. I like to prep at home just to give me more pad time. In winter I exclusively prep at home.

 

[rharshberger]

I've only used BP and single-use composite motors so far, and to be honest have no real interest in doing reloads. But I am really curious about long it takes to prep a motor, once you know what you're doing. How long does it take you to prep a single motor? Do you ever do them at the field, or only at home in advance?

As I said, I am just curious.

I do most of mine in the field, and between paying attention to launches and safety calls it can take me 10 minutes or so to build a reload, I never try and build a motor quickly, SPEED IS A BYPRODUCT OF PRACTICE (which well known/famous guitarist said that last bit?)

 

[mhanna]

You can build an Aerotech motor in 5 to 10 minutes. Cesaroni in about 5 minutes. I always build my motors at the field in case I need to change plans due to wind or other field conditions.

 

[neil_w]

OK, that is a bit quicker than I imagined, not too bad. Thanks for the replies. One day maybe I'll venture there.

 

[rcktnut]

5-10 minutes here also, do them at home.

 

[Buckeye]

I take longer than most. I have built AT reloads for 20 years, but I still meticulously lay out all the parts, read the instructions, and carefully clean up the grease. I can never be too sure, because Aerotech has the annoying habit of changing the designs of delay assemblies and forward closures, rewriting instructions, giving incorrect instructions, adding addendums to the instructions, and renaming their products with new abbreviations. My pet peeve is the o-ring. Some reloads put the thick o-ring in front, some in the back. Some reloads need the additional forward seal disk o-ring. Grrr...

CTI reloads I can do in my sleep.

All that said, I can proudly say that I never, ever, had a reload fail on me.

 

[Zeus-cat]

I would say about 10 to 15 minutes for an Aerotech high power reload. I do them at the field and also follow the instructions for every one; which are awful by the way. I take care so that the grease never touches the delay grain or the propellant. They are not really difficult to do, but you have to pay attention to what you are doing and read the awful instructions carefully. You should have an experienced person help you with the first one, or twenty.

 

[dhbarr]

And some wipes, and some dry paper towels. SO much better.

 

[noffie79]

I really like building my motors. CTI are gravy, AT is a bit more time consuming, but it's a rewarding process. I always lay out my parts and read the instructions. Here is a great video from Apogee on building reloads. Not all are the same, so always have instructions at the ready.
https://youtu.be/g0GsbQS7GKI

 

[Dad Man Walking]

SPEED IS A BYPRODUCT OF PRACTICE (which well known/famous guitarist said that last bit?)

OK, I'll bite. Google wasn't helpful. And the answer is...?

 

[rharshberger]

OK, I'll bite. Google wasn't helpful. And the answer is...?

As long as my memory hasn't totally failed me it was John Petrucci of Dream Theatre from an issue of Guitar Magazine.

 

[byoungblood]

5-10 minutes on my AT motors. I find that I tend to be able to assemble them a little faster at home vs working on my tailgate at the field. Because I'm also having to keep an eye on my 5 year old son, I've just found them easier to load them the day before a launch.

 

[aerostadt]

I would say it could take up to 45 minutes for a 29 mm to 54 mm AT motor. Some of the AT motors with a seal disk, I want to make sure that I get it correct. Actually, the 54 mm AT motors take less time than a 29 mm H-motor can, because there is no seal disk. If no pressing problems come up, I would say about 50 sec. for a CTI and most of that time is adjusting the time delay. It may take longer for the CTI than 50 sec., if you need to add a contraption for extra ejection powder( but the same thing can happen for an AT motor). Otherwise, the CTI is incredibly faster than AT. If you have a complicated model that requires a lot of prepping, CTI is the way to go.

 

[Donaldsrockets]

I would usually spend about 4-5 minutes on an AT reload. I like to test fit parts prior to assembly to avoid any unexpected surprises.

One time I had a liner for a 38/480 I285R reload that was so tight that I had to sand the crap out of to get it to fit and that was after I had already greased it. I had to wipe the grease off and then hit it with some 100 grit sandpaper. I think I spent about 30-45 minutes on THAT reload. Ever since then I made it a habit to test fit liners first.

If the paper liners are too tight, all you have to do is remove the first layer or two from the liner and you've got it made. Same thing with the propellant grains. If the phenolic liners are too tight, well, other than obtaining a replacement from AT, sanding is the only option.

 

[eggplant]

I would say it could take up to 45 minutes for a 29 mm to 54 mm AT motor. Some of the AT motors with a seal disk, I want to make sure that I get it correct. Actually, the 54 mm AT motors take less time than a 29 mm H-motor can, because there is no seal disk. If no pressing problems come up, I would say about 50 sec. for a CTI and most of that time is adjusting the time delay. It may take longer for the CTI than 50 sec., if you need to add a contraption for extra ejection powder( but the same thing can happen for an AT motor). Otherwise, the CTI is incredibly faster than AT. If you have a complicated model that requires a lot of prepping, CTI is the way to go.

Just to be clear, there is such as thing as a 54mm seal disk and it is required for longer/hotter 54mm motors.

 

[cbrarick]

Get a box to dump your parts into for the aerotech loads. I have a plastic container the size of a shoebox. Works on most motors.

 

[markkoelsch]

As long as my memory hasn't totally failed me it was John Petrucci of Dream Theatre from an issue of Guitar Magazine.

Which is a paraphrase of many musicians before the incredible John Petrucci.

 

[blackwing94]

And when you clean up your AT motor casing after a successful launched, use your own trash sack, and take your trash home with you. Then when you realize you dumped out the seal disk into the trash, you can dig through the trash in private!

 

[Steve Shannon]

I would agree that the average AT reload takes 5-10 minutes. For smaller motors I usually don't even decide what I'm going to use until I'm at the launch and see the conditions, so I build them on site.
However, for some larger motors, 75 and 98 mm, Aerotech has recently issued advice to glue grains. Those simply must be prepared a day or two in advance and that preparation takes me an hour or so. Those 75 and 98 mm motors that do not require glued grains are typically the easiest Aerotech loads to build in my opinion.
Snap ring case Loki or Amw loads typically take me just a few minutes also. I do them on site.


Steve Shannon

 

[pcalvin]

And when you clean up your AT motor casing after a successful launched, use your own trash sack, and take your trash home with you. Then when you realize you dumped out the seal disk into the trash, you can dig through the trash in private!

This is just so true.

 

[Handeman]

And when you clean up your AT motor casing after a successful launched, use your own trash sack, and take your trash home with you. Then when you realize you dumped out the seal disk into the trash, you can dig through the trash in private!

This is just so true.

Don't I know it.... I had to make the call of shame to the guy that took the trash home from the last launch. My 54mm seal disk is in his range box now...

I only do my EX motors at home the night before. I have all AT cases in 24, 29, 38, and up to 4 grain 54. Baring a liner that needs sanding, or the glassine removed, I spend 5 minutes or less putting a reload together. I did buy an actual AT 38/480 case because my DR Rocket case in that size had issues with liners being tight. I found that if it didn't fit the DR Rocket case, it would slip right into my friends AT case. I got tired of borrowing his case and bought my own. I think I've only had to use it once since.

As I said, I only do EX motors beforehand, all the commercial reloads are done at the field so I can fly the conditions. Some days you go with a smaller motor, some days you go bigger. With the EX, it's either Go or No Go.

 

[blackbrandt]

I can get most loads together in about 5 minutes or so. I take the most time with Aerotechs. However, I can pull off a Loki load in 2 minutes or less.

 

[ColumbiaNX01]

no reason to rush. It can take me around 10 minutes or so. No reason to try to beat the clock. That can cause a major screw up. 10-15 minutes is good. This isn't jeopardy. You dont have to beat a clock.

 

[cavecentral]

I used to load all my AT cases at the beginning of the season and have them ready. Fly them all by the end (clean / reload as needed). Doing them in bulk helped, but yeah I rarely do them in the field anymore. No lost parts, no rush, etc.

I need to start cleaning them in the field instead of the several weeks later . . .

 

[mccordmw]

A CTI reload takes 30 seconds. Take it out of the package, drop it in the aluminum case, and screw it in. Not much to it.

 

[Steve Shannon]

no reason to rush. It can take me around 10 minutes or so. No reason to try to beat the clock. That can cause a major screw up. 10-15 minutes is good. This isn't jeopardy. You dont have to beat a clock.

Very good point. And don't do it when you're distracted either [emoji573]

 

[o1d_dude]

I try to avoid assembing Aerotech reloads on the range but have done it when necessary.

CTI is easy peasy and can be done anywhere. Drilling out the delay (if necessary) doesn't take any time at all.

 

[Nathan]

. . . I never try and build a motor quickly . . .

And take your time making sure all of the recovery quicklinks are attached correctly too. Don't ask me how I know . . .

 

[ECayemberg]

A CTI reload takes 30 seconds. Take it out of the package, drop it in the aluminum case, and screw it in. Not much to it.

Not a rant at you, Mark, but this brings up a point I'd like to emphasize.

I've seen countless flights where people do exactly as you describe..... and then they have a ballistic recovery. I fly a lot of CTI and appreciate the ease of assembly, but so often I hear them slated or sold as "pull out of the package, slide in the casing, and slide in the rocket". While this is mostly true, I have a strong hunch that statements such are taken literally, and lead primarily to failure to adjust delays on all the sizes and other anomalies caused by a speedy assembly (such as mis-threading the nozzle end of the 38 loads). Powder may have to be added for larger airframes, etc....blanket statements taken literally in High Power rocketry can be dangerous.

I can assemble most reloads with my eyes closed, but I too like to go slow and double check to make sure everything is just right. 99% of the reloads I fly are prepped at home in a controlled environment in advance. As others have said, it's not a race....take the time to make sure its done right, whether that's 5, 15, or 90 minutes.

This has been a public service announcement from the Frozen Tundra:wink:

-Eric-