Holes in the grains

[prophecy]

Lol!!! Patrick, it's comments like this that you need to ignore, there's bullies everywhere and we all started from the beginning somewhere and some people forget that.......It will be fine, just burn it!!!

Hello Preston,

If you go back and read my comment, you'll see that it was directed at CarVac, and I was actually accusing him of being condescending, essentially saying folks in glass houses shouldn't throw stones. Nowhere in my post did I mention or even reference the OP or his question.

By the way, it was nice speaking with you at Thunderstruck.

Be well

 

[dave carver]

It looks to me like the holes are leftover from the hole drilling process, most likely from a jig used to hold the grain in place. This is a semi-educated guess but the uniformity of the indents lead me to that conclusion....but I might and could be wrong...I often am

 

[pnobile]

I guess it shouldn't have been directed at you or anyone directly, but to me this is a hobby and too many people take it way too serious and always try and out do each other like its a competition or they need to prove themselves somehow in every thread. I agree many comments posted by some are condescending.....too bad but that's the reality of it.

Preston

Hello Preston,

If you go back and read my comment, you'll see that it was directed at CarVac, and I was actually accusing him of being condescending, essentially saying folks in glass houses shouldn't throw stones. Nowhere in my post did I mention or even reference the OP or his question.

By the way, it was nice speaking with you at Thunderstruck.

Be well

 

[SS/EA 6BBL 71 Cuda]

These look like indentations, not bubbles. I've flown far worse in grains that I made. I'd fly them, but that's me.

I've flown many AMW loads that looked similar to those grains with no issue, but that's just me. I'd fly it as I have not had any problems in the past....

Preston

Seconded; a few bubbles and voids are normally found in AMW, Kosdon East, Kosdon loads. Nothing to worry about. I have NEVER seen a properly assembled AMW load fail....ever.

-Eric-

Thirded, saw these a lot in L1860 and L850 loads in the past. I think the defects here are bubbles that got cut in half.

Like Kevin said, i always wondered if they were indentations instead of bubbles...
Patrick, i may be the *darkhorse* advice wise here but, i agree with all four of the opinions above.
I've burned AT LEAST 200,000ns. in AMW motors and, NEVER had a CATO...Seeing grains that looked MUCH worse.

You will be ok, just fly it and, enjoy the show.

 

[Rocketry nut]

Prophecy,
I knew who your comment was directed to so don't sweat it.

Preston,
Yes, I've gotten that vibe from some people on here who always have something smart to say. I usually just ignore them because they either crave attention(which you're not getting) or don't really know what they are talking about. There is always that one know it all in the bunch...

Gustav,
I'll post pics after next weekend. I trust that the Midwest crew knows what they are talking about when it comes to AMW. After all you all fly an unbelievable amount skidmarks Unfortunately this will only be my 4th AMW motor and had never seen this before on any previous motors.

 

[georgegassaway]

Bubbles in general are bad. For some motors it might not matter, for others it can cause Catos.

NEVER fill grain holes or dents with epoxy or anything solid! When the flame front gets to the epoxy then you have a solid chunk of epoxy being thrown thru the nozzle throat. That could temporarily cause a pressure buildup that could cause a Cato.

Instead of epoxy, you could carefully "dab" some Petroleum Jelly over the surface of the hole (and nowhere else). That will inhibit the burning so that instead of a larger surface area from the hole, the flame front won't burn from the inside surface that is coated. Since the grain is a classic coreburner, it's burning out sideways from the center core, so there ought not be any serous side-effects from doing that,

But above all you ought to contact the manufacturer and find out if they are made that way, or why they think yours look like that.

If they were voids, I would not fly them. I' d either get them replaced or if voids are a common issue and not a rare thing, buy motors from someone else who can routinely mix propellant that does not have voids. Routine voids means poor quality control. I m NOT saying that is the case here. But always an issue to be aware of and consider.

- George Gassaway

 

[Ethan]

Small, isolated mechanical voids like this are not an issue, with the safety margins built into hobby motor designs. The effect would be lost in the noise from other manufacturing variabilities.

Porosity, or lots of small,evenly distributed bubbles as a result of gas generation in the mix is what causes problems.

 

[boomtube]

Here we were, moving right along having a serious discussion about a serious problem and somebody has to go and get squirrely on us.

 

[Rocketry nut]

The winds were howling like mad, but the L1300 burned it's 2 full seconds of awesomeness no problem Man I wish they still made these...

Due to the wind my Eagle Claw only reached 6924'. Thanks again Preston for selling me this so I had the opportunity to finally fly my own Blue Baboon

 

[pnobile]

Great pic and the L1300bb is always an awesome motor!! Funny how this discussion many of us that have flown AMW motors said they never had a failure......well this weekend in South Carolina, I had an AMW 75/2500 L700BB fail!!! Forward bulkhead blow by, which torched my whole booster section of my Broken Arrow XP 4in. Casing is shot, but was able to salvage the nozzle, one snap ring, and nozzle washer......Patrick glad the motor worked out for you and if I didn't like AMW so much I sell you more of my AMW 54/2550 loads....

The winds were howling like mad, but the L1300 burned it's 2 full seconds of awesomeness no problem Man I wish they still made these...

Due to the wind my Eagle Claw only reached 6924'. Thanks again Preston for selling me this so I had the opportunity to finally fly my own Blue Baboon

 

[ECayemberg]

Great pic and the L1300bb is always an awesome motor!! Funny how this discussion many of us that have flown AMW motors said they never had a failure......well this weekend in South Carolina, I had an AMW 75/2500 L700BB fail!!! Forward bulkhead blow by, which torched my whole booster section of my Broken Arrow XP 4in. Casing is shot, but was able to salvage the nozzle, one snap ring, and nozzle washer......Patrick glad the motor worked out for you and if I didn't like AMW so much I sell you more of my AMW 54/2550 loads....

View attachment 171293

View attachment 171294

View attachment 171295

View attachment 171297

Lessons learned in this thread:

1. I take full responsibility for Preston's cato; should've never said "I've never seen...".
2. Never name a rocket "Broken..."; rocket is destined to become its namesake.
3. Patrick is back at it again in full force. I see 3" motors in the very near future!

Preston, I'd be curious to see the 2500 hardware...did the gases go around the outside of the forward closure, through the recovery attachment hole in the fwd bulkhead, or did the case suffer a burn through near the base of the closure? I know my Blue Baboons always came with convolute liners as BB runs a bit hotter. Anyway, glad to see Patrick's motor burned well; and bummed for you Preston!

-Eric-

 

[SS/EA 6BBL 71 Cuda]

Funny how this discussion many of us that have flown AMW motors said they never had a failure...

We have lost a true Jedi Master along the way...Heads are bowed.

1. I take full responsibility for Preston's cato; should've never said "I've never seen...".

Oh....no....you....don't...:no: Don't you be putting the *WHAMMY* on us "Other Peoples"!
I STILL have like (5) AMW 75mm motors in storage. Strange things can happen between now and, 3...2...1.

Sorry too hear about your loss Preston, good job Patrick...apologize about not returning on Sunday.
Was feeling my age due to lots of walkage and, wind burnage...We will meet up soon and, burn a *BIG Fat One* in field somewhere down the road of life!

 

[Rocketry nut]

Sorry about your mishap Preston There is a first for everything, but I'd still blame Eric If you ever get sick of burning those 2550 loads you can send them this way(especially the K1000). I may have to start looking into gorilla loads since no one else makes anything for that case or I could get into EX...

Eric, just 3in? How about 4?! Planning on getting my L3 later this year(MWP time frame) and will be burning with the big boys before long.

Gus, when are you burning that N5600?

 

[pnobile]

Eric, it was the original 75/2500 bulkhead that has probably 15 or more motors burned on it and its been beaten around for awhile now, so I guess this time was its final motor it wanted to handle. It actually burned a hole right in the middle of the bulkhead and melted the end of the casing inwards. It did have the convolute liner as well. Oh well, gotta break out the reserve AMW 75/2500 hardware now.

Patrick I think I have 5 AMW K1000's skids left, but that's one of my favorites so you probably won't get 'em from me!!!

Gus, I have 20+ 75mm AMW motors left in storage and I won't let this get me down, as I will still burn them any chance I get!! :tongue:

Sorry about your mishap Preston There is a first for everything, but I'd still blame Eric If you ever get sick of burning those 2550 loads you can send them this way(especially the K1000). I may have to start looking into gorilla loads since no one else makes anything for that case or I could get into EX...

Eric, just 3in? How about 4?! Planning on getting my L3 later this year(MWP time frame) and will be burning with the big boys before long.

Gus, when are you burning that N5600?

 

[SS/EA 6BBL 71 Cuda]

Sorry about your mishap Preston There is a first for everything, but I'd still blame Eric If you ever get sick of burning those 2550 loads you can send them this way(especially the K1000). I may have to start looking into gorilla loads since no one else makes anything for that case or I could get into EX...

Eric, just 3in? How about 4?! Planning on getting my L3 later this year(MWP time frame) and will be burning with the big boys before long.

Gus, when are you burning that N5600?

Pat, i was going to burn the N5600 at Wildman's Memorial Day event (the Sunday edition) in my Gizmo XL. That rocket has always had a great *Up* but, an interesting history with *The Down*. I think we've got that problem taken care of now with eliminating the Tether and, going to an Archtype Cable Cutter System...
If so you will see it at an OAMC launch someday (or MWP) on something REALLY big!

K1000? One of my personal favorites of the smaller AMW Skids! VERY LOUD...

 

[rdh8]

since no one else makes anything for that case or I could get into EX...

Have you looked a the CTI compatible reloads?
https://cart.amwprox.com/index.php?...egory&virtuemart_category_id=52&limitstart=18

And there are soon to be a couple more loads.