reloading motor in the field

[sgirard]

Hello everyone!

I made some inquiries 2 years ago about motor casings and reloads. I did not follow up with the information at that time. I would like to save money like anyone else so I’m planning on educating myself.

I fly only mid-power rockets with mostly 24mm motors. I have only one question I would like to know before I start. Is it practical to fly, clean, reload, and fly again with only one casing in the field? I am interested in the larger selection of motors with the reloads over single use.

Thanks

steve

 

[SkiesAreClear]

It’s practical if you have all the right supplies handy, but can be cumbersome. I do it pretty frequently but it doesn’t end up being as quick or effortless as a disposable motor. If you have all the right supplies to disassemble/reassemble a motor handy and a good place to do it (table is great, doing it on your lap is rough, doing it on the ground isn’t fun), it can be done without too much pain.

I love the 24/40 Aerotech case and highly recommend it, but it’s definitely not the best option if you are optimizing on number of flights per day at the field. Can probably fly at least one or two single use motors in the time it takes to disassemble/reassemble a reload.

 

[terryg]

It can be done but it much easier at home. I only do it for multiday launches. Another factor is that you should simulate the launch with software to determine the best delay time to use and how high it will go. You will eventually get multiple cases, but at first a mixture of reloads and single use might be best.

 

[Neutronium95]

It also depends a lot on what brand of motors you're using. Assuming I'm flying a rocket with electronic deployment where I don't need to set the delay, I can turn a Cesaroni 29mm motor around in less than a minute, since assembly is so simple, and they tend to not really need much if any cleaning post flight. An Aerotech motor will require a thorough cleaning, and the assembly process is much more involved.

 

[Hobie1dog]

Sure, a table with a good bath towel to put parts on.

 

[Getmore]

I do it all the time.

 

[tsmith1315]

I always assemble at the field.

To clean small cases, I take a dowel and shop towels with WD40. Stiff brush for threads, nitrile gloves to keep hands clean and trash bags to toss it all in.

 

[David Schwantz]

A small Tupperware tray is handy to keep all the parts in. Never, never let anyone disturb you while building a motor. Missed steps are a disaster!

 

[DAllen]

Unscented baby wipes, case brushes from Chris Rocket supplies, a tray to put the reload items in and a steady table to work off of are all your friends.

 

[kjhambrick]

Back in the olden days, I always built my motors at the launch site because one never knows what the conditions will be until you arrive at the site.

In fact, I built my first motor at home before the launch for the first time last summer ...

The most annoying problem for me on-site was dropping o-rings in the dirt ... CLEAN them very well if you do, especially if they've been lubed before they land in the dirt !

Someone mentioned a bath towel ... I used a canvas painter's tarp over my table.

Same idea -- the bath towel or tarp help keep dropped parts ( especially small nuts and washers and o-rings ) from bouncing off the hard table top into the dirt.

I often reloaded a single case onsite for 2nd or even 3rd flights.

I have a set of bottle brishes that fit the my 18,24,29,38,54 mm RMS cases.

A paper towel wet with WD-40 then wrapped around a bottle brush does a pretty good job on the gunk but keep that steel handle away from the aluminum threads on your cases !

After the oiled paper towel treatment, swab with a wad of dry paper towel and reload and fly the rocket !

But now that I read that @tsmith1315 uses wooden dowels, I am going to try them instead because every time the hard twisted steel bottle brush handle scrapes the softer aluminum threads of my cases it is like nails on a blackboard to me

HTH !

-- kjh

 

[techrat]

When I'm out at a launch, I try and optimize my available time to fly as many rockets as possible. If our Sunday launch starts at 12:30 and ends at 5, I want to get in at least 10 launches. With stuffing in a motor, getting in the ignitor, attaching a chute, stuffing the rocket body with wadding and dog barf and then recovering the rocket after the launch, that's already 30+ minutes, assuming the rocket goes on the first try. While I'm waiting for the folks to count down to my particular rocket, I might be prepping others, so I try and be as efficient as possible.

I have a 24/40 case but I've never done the reload at the field. If you drop one of those o-rings in the grass, you're not finding it again. But that's not even the biggest problem -- cleaning out the case after a launch can be a chore that takes 15+ minutes by itself, getting the cardboard liner out is usually the toughest part, and my hands get filthy doing that, washing up after is quite the job. Unless you have the stuff with you to cover every eventuality, you'll find it's more work than it's worth.

I generally load the motor the night before, fly it as if it's just another disposable, and then clean it up when I get home, and use it again the next month. So yes, out of 10 launches, just one is my reloadable case, but, that's because I'm hustling to get in those 10 launches.

As with anything, your mileage may vary.

 

[tsmith1315]

motors at the launch site because one never knows what the conditions will be until you arrive at the site

Exactly.

But now that I read that @tsmith1315 uses wooden dowels, I am going to try them instead because every time the hard twisted steel bottle brush handle scrapes the softer aluminum threads of my cases it is like nails on a blackboard to me

A dowel is also useful to safely nudge stuck-on bits inside!

Also, I always build with the instruction sheet open, usually on the sheet itself. Something to hold that down is helpful, but not a clipboard. Too easy to bounce and roll.

 

[mtnmanak]

For smaller motors (29mm and below), reloading at the field is not a problem. Larger motors tend to need a lot more cleaning apparatus (still doable, but I usually do not want to deal with the hassle of cleaning and reloading a big motor case at the field).

Lots of great suggestions for field cleaning above. I bring a 5 gal home depot bucket and water to the field to clean parts. To transport the water, I use collapsible camping containers like these:

https://www.amazon.com/gp/product/B0717B6BTK
Even if you only have a car, the empty 5 gal bucket is easy to transport (can double as a holding container for parts, rockets, etc) and the collapsible water containers come in different sizes, so you can stash them in various open spots in your vehicle without fear of the water leaking out. On a multiday launch, bring the collapsible containers back to the hotel/campground and refill.

I have tried a LOT of case brushes and have found the ones that Brian (@DDSrocdoc) sells at BJAAM to be the best I have found. Pro tip - use the brush a size up (i.e. - use a 29mm brush in a 24mm case) to get the best cleaning.

https://rocketsok.com/case-brushes/

 

[DAllen]

And save yourself some $$ with casing brushes and get a (new) toilet bowl brush for the 75mm. I have one that’s dedicated to that purpose.

And as stated previously a dowel longer than the case is also your friend.

 

[kjhambrick]

<<snip>>

A dowel is also useful to safely nudge stuck-on bits inside!

Yes !

I salvaged a nice old threaded ash commode plunger handle that outlasted the rubber bizness end to scrub the grimy bits out of my cases.

The hard wood stick with the nice old threads makes an effective carbon removal tool ...

I had it in my rocket box for years -n- years and now I have to go up in the attic to find it !

Thanks for reminding me Tim

Also, I always build with the instruction sheet open, usually on the sheet itself. Something to hold that down is helpful, but not a clipboard. Too easy to bounce and roll.

Me too ... but make sure the wind can't pick up your instruction sheet and scatter RMS parts all over the place !

And I must confess that I broke my 'build it on-site' rule this afternoon ...

AARG is doing a 'bonus' launch tomorrow in Hutto, TX from 14:00 to 16:00 so there won't be a lot of time for on-site prep.

I opened, inspected, cleaned and built an old RMS 38/360 I357T ( Batch Aug 2 1996 ) and also a new RMS 38/480 I225FJ to fly in my Vulcanite.

Either motor will send "Spock's Johnson" up to 3,800 ft at 89 ft/sec off the rail ( I225FJ ) or 4,000 ft at 119 ft/sec off the rail ( (I357T ).

I'll select one or the other, depending on the wind ( forcast is now 7 -or- 8 mph, depending on who's talking ( Windy or WUnderground ) ...

Or maybe I'll just watch @JimJarvis50 fly his VOS System ...

And all this depends on whether I can finish a job for a customer tomorrow morning in time to get there and to launch and recover.

I think I am going to need those X-d fingers now, Tim

Please -n- Thank You !

-- kjh

 

[tsmith1315]

I think I am going to need those X-d fingers now, Tim

Indeed you do!

And all this depends on whether I can finish a job for a customer tomorrow morning in time to get there and to launch and recover.

And one more for that...

 

[kjhambrick]

Thanks Tim, I needed that

 

[J Blatz]

With practice you can make reloading pretty fast. I don’t fly much any more but I can turn around a 29/40-120 AT motor in less than 5 minutes under decent conditions. I know all the parts by sight. TBH same for many Aerotech reloads.

 

[sgirard]

thanks for all the information. Now I know it's an option I will start to wrap my head around everything. I will never fly anything larger than a 29mm because I don't plan on becoming certified. I fly low and slow because of my field size, and physical limitations. Just sitting here, I keep thinking of all kinds of questions. I think my best bet is to make a list and travel the 80 or so miles to a launch in Texas. I don't travel well but think it would be worth the trip. That way I can hopefully talk to some of the guys and get answers (assuming I'm allow in the area and can talk to them). I have always flown by myself and have never seen anything larger than a E motor before, but I'm sure you will hear from me again as I get into it. I've always wanted to see a high power launch in person.
Thanks again for the encouragement.

 

[kjhambrick]

Speaking of instruction sheets ...

This is my I225FJ Instruction sheet.

Is that a dead worm or was someone eating pasta while they packed my I225FJ ?

Either way, I hope it is a lucky strand of pasta or a benevalent worm

-- kjh

 

[Steve Shannon]

It’s possible until you lose one rocket and it takes your only case with it. I recommend a spare. Then you’ll probably never lose it.

 

[troj]

As others have basically said - it's quite practical, if you come prepared.

- Baby wipes (cleaning cases and your hands)
- Trash bag
- soft-bristled brush
- Appropriate size dowel to poke things through the casing
- Container of lube
- Knife (sometimes things need to be trimmed a bit)
- Scissors (opening the reload bag)
- Small screwdriver (poking flashing out of nozzles)
- Needle nose pliers (multi-tool is handy - knife and pliers in one!)

Those are the main things you need.

-Kevin

 

[Raythain]

As others have basically said - it's quite practical, if you come prepared.

- Baby wipes (cleaning cases and your hands)
- Trash bag
- soft-bristled brush
- Appropriate size dowel to poke things through the casing
- Container of lube
- Knife (sometimes things need to be trimmed a bit)
- Scissors (opening the reload bag)
- Small screwdriver (poking flashing out of nozzles)

Those are the main things you need.

-Kevin

Only thing I’d add to this list is a rubber strap wrench or similar. I’ve had forward closures get sticky when they burn hot, and are a pain to get off without marring the case.

Also, unscented makeup remover wipes do wonders for cleaning out the casing, especially the threads.

 

[terryg]

I would add needle nosed pliers to remove the spent delay elements from the forward closure.

 

[sgirard]

I've found several videos on how to assemble a reloadable motor but haven't seen anything showing what's involved in cleaning a casing before it's ready to reload. Does anyone know if there are some videos out there showing the cleaning process?

 

[David Schwantz]

I've never seen a video, although I have not looked for one. Lots of ways, soap and water, my preferred method, baby wipes, WD-40, gun solvent, rag and dowel, scrub brush and lots of elbow grease. Lots of venders have case brushes, mine I chuck up in a drill. Just get all the old grease off and any burnt deposits inside the case. I also use a lead removal cloth that is used in gun cleaning.

 

[troj]

I would add needle nosed pliers to remove the spent delay elements from the forward closure.

Yeah, good point - I always take my Leatherman to the field, so I forgot about the pliers!

-Kevin

 

[tsmith1315]

I've found several videos on how to assemble a reloadable motor but haven't seen anything showing what's involved in cleaning a casing before it's ready to reload

Bottom line, you’re just wiping it down. Then clean the stubborn spots.

With a 29mm like yours:
Most of the time, I soak a shop rag in WD40 and twist it through with a dowel. Double it up to make it fit tight. Push it through a couple of times and clean the threads with a brush. If parts of the old liner stick, use the dowel to nudge them. Run some dry towels through, and that’s usually good.

Note: I grease the outside of my liners and I think it helps with removal. Not everyone agrees.

 

[David Schwantz]

I used to grease the outside also, but I think the burned grease little nubbies are very hard to remove completely. But this is just me, I may be wrong. My wife says I am.

 

[n3tjm]

On the field I just did quick wipe down for quick reloading. I wait till I get home or after the launch is over to do a more thorough cleaning. This is very easy to do if you wipe it down while the motor is still warm, especially the delay and ejection residue and if you didn't grease the liner. Before going home, at least give the motors a quick wipe down. They are harder to clean when cold.

I been using reloads since they came out in the 90's, and I have learned that it's best not to grease the liner. To many times the grass has glued the liner to the case. Not usually an issue if cleaning while the case is still warm, but you still have the messy grease to clean up. There are a few reloads that rely on grease to help seal the motor, but those are a relatively few of them.

When I did my L3 the vendor helped me assemble my L3 motor. (That size motor it's nice having a extra set of hands). Well he greased the liner, and by the time I got the rocket back it cooled and the liner glued itself to the case. I couldn't remove it in field so I had to wait till I got home and did it the the hard way. Fwd bulkhead, block of wood, mallot. Anchor the case down. Slowly hammer the liner out.