AeroTech Open Thread

[dhbarr]

Thanks. Very helpful... my online persona is happy. I expect great customer service, not "You shouldn't use a -4 in a BT50 rocket." WHY WOULD THAT MAKE ANY DIFFERENCE? I did not say it separated or stripped the chute or zippered. I said "It blew the rocket in half!" And it did so at apogee. Everyone one on field heard it go off like a shotgun.
I thought maybe they'd say, "Yeah... the early ones had an issue, file a claim". Instead they insulted me with a -4 is too short for a BT-50

Consider whether or not it makes sense to keep re-stating what you hoped someone else would say.
Consider whether or not "shotgun" "idiot" "admit" "exploded" "insulted" are the kinds of words you'd hoped you'd say.

 

[smstachwick]

Let's do this again!

Thanks. Very helpful... my online persona is happy.

Didn't you throw a similar tantrum over a difference of 6 clicks in the OpenRocket beta thread? I haven't had a genuine issue with your behavior since then but I have seen that you're more on the aggressive side than is typical.

I expect great customer service,

Then contact the customer service department. It's listed on their website and is easy enough to find. Less obvious is that it's in Gary's ( @AeroTech 's) signature. Turn your device sideways if you're on mobile. Please be more patient with Jenn than you were with Gary.

not "You shouldn't use a -4 in a BT50 rocket." WHY WOULD THAT MAKE ANY DIFFERENCE?

You've had the considerations of ejection charge size explained to you by the master. Clearly that consideration was weighed too heavily in that early batch but it does need to be weighed.

I did not say it separated or stripped the chute or zippered. I said "It blew the rocket in half!" And it did so at apogee. Everyone one on field heard it go off like a shotgun.
I thought maybe they'd say, "Yeah... the early ones had an issue, file a claim". Instead they insulted me with a -4 is too short for a BT-50

That's not an insult. For most rockets, that's just a fact. Clearly yours is a bit different than what was anticipated in the design of these motors and they were redesigned to be more accommodating.

 

[Initiator001]

Motors should be used within 5 years of manufacture to deliver certified performance specifications. They may be fine beyond that time, depending on storage conditions, but that is the NFPA requirement.

Darn.

I guess it's too late to fly my Coaster motors.

 

[3stoogesrocketry]

Thanks. Very helpful... my online persona is happy. I expect great customer service, not "You shouldn't use a -4 in a BT50 rocket." WHY WOULD THAT MAKE ANY DIFFERENCE? I did not say it separated or stripped the chute or zippered. I said "It blew the rocket in half!" And it did so at apogee. Everyone one on field heard it go off like a shotgun.
I thought maybe they'd say, "Yeah... the early ones had an issue, file a claim". Instead they insulted me with a -4 is too short for a BT-50

Was there a coupler where the "rocket blew in half" or was it in the middle of a single tube ?

 

[AeroTech]

I checked and the C12-4 still uses the original ejection charge at 0.5 grams because that is appropriate for most of the rockets they are being flown in. The charge was reduced early on for the longer delays only, since they are typically used in smaller rockets.

 

[AeroTech]

Darn.

I guess it's too late to fly my Coaster motors.

View attachment 538084

Bob, those Coasters were made long before NFPA 1125 was a gleam in G. Harry Stine’s eye.

 

[gdjsky01]

Ok fine. I am VERY critical of vendors (or others) than hawk stuff has been shown to be sub-par. OR has a UI that is awful. AT apparently thinks the C12-4 is used in BT-80 rockets and nothing smaller. Somehow other vendor figure out how to create C motors that work correctly in a wide range of rockets. Not AT. Fine. I am so sorry I point out that we have a terrible UI for launching in OR and that I can not be the only one to notice, and AT's early C12's had too much BP and will not do anything to make it right. Fine. I am apologize to everyone that I expect better of people and especially vendors. And too bad for me. LOL... Got it. Fan boyz unite! How sad. Yes, I expect better and complain when its not.

PS What I don't get is why there is no cry of foul when an vendor says "A C12-4 is not appropriate for a BT-50 model"? WHAT damn difference would that MAKE if the charge blows the rocket in half? Its maddening. The delay has NOTHING to due with what happen!

 

[smstachwick]

Ok fine. I am VERY critical of vendors (or others) than hawk stuff has been shown to be sub-par. OR has a UI that is awful. AT apparently thinks the C12-4 is used in BT-80 rockets and nothing smaller. Somehow other vendor figure out how to create C motors that work correctly in a wide range of rockets. Not AT. Fine. I am so sorry I point out that we have a terrible UI for launching in OR and that I can not be the only one to notice, and AT's early C12's had too much BP and will not do anything to make it right. Fine. I am apologize to everyone that I expect better of people and especially vendors. And too bad for me. LOL... Got it. Fan boyz unite! How sad. Yes, I expect better and complain when its not.

PS What I don't get is why there is no cry of foul when an vendor says "A C12-4 is not appropriate for a BT-50 model"? WHAT damn difference would that MAKE if the charge blows the rocket in half? Its maddening. The delay has NOTHING to due with what happen!

Let’s clear this dispute out of this thread, shall we? My DMs are open if you wish to scream into the void.

 

[AeroTech]

Demo of the new K750ST Super Thunder reload for the RMS-75/1280 casing. Photos by Dan Michael.

 

[3stoogesrocketry]

Gary I would personally like to say congratulations on making Aerotech / RCS 40 years old this year. Here to another 40 years .

 

[AeroTech]

Gary I would personally like to say congratulations on making Aerotech / RCS 40 years old this year. Here to another 40 years .

Thank you, and thanks to the great team members over the years that helped make it happen!

 

[rcktnut]

Ok fine. I am VERY critical of vendors (or others) than hawk stuff has been shown to be sub-par. OR has a UI that is awful. AT apparently thinks the C12-4 is used in BT-80 rockets and nothing smaller. Somehow other vendor figure out how to create C motors that work correctly in a wide range of rockets. Not AT. Fine. I am so sorry I point out that we have a terrible UI for launching in OR and that I can not be the only one to notice, and AT's early C12's had too much BP and will not do anything to make it right. Fine. I am apologize to everyone that I expect better of people and especially vendors. And too bad for me. LOL... Got it. Fan boyz unite! How sad. Yes, I expect better and complain when its not.

PS What I don't get is why there is no cry of foul when an vendor says "A C12-4 is not appropriate for a BT-50 model"? WHAT damn difference would that MAKE if the charge blows the rocket in half? Its maddening. The delay has NOTHING to due with what happen!

A picture is worth 1000 words. Lets see what happened.

Here is the thread I started a while back. Had the opposite problem of what you had.
https://www.rocketryforum.com/threads/wimpy-q-jet-ejection-charge.160955/#post-2045590

 

[AeroTech]

A picture is worth 1000 words. Lets see what happened.

Here is the thread I started a while back. Had the opposite problem of what you had.
https://www.rocketryforum.com/threads/wimpy-q-jet-ejection-charge.160955/#post-2045590

I’m waiting to see a picture as well.

The short-delay motors are generally used in larger, heavier rockets that need more ejection charge to pressurize a larger internal volume. That is why they contain more ejection charge. If you happen to use one in a small-diameter fantasy rocket with lots of drag from appendages or other add-ons, I would recommend that the charge be reduced by the user. This is easier to accomplish with Q-Jets than with black powder motors. The plastic cap is removed, the charge can be adjusted and the cap replaced.

 

[Charles_McG]

So perhaps we should be thinking of the C12 as a skinny C11, rather than a thrusty C5?

 

[rdrown]

PS What I don't get is why there is no cry of foul when an vendor says "A C12-4 is not appropriate for a BT-50 model"? WHAT damn difference would that MAKE if the charge blows the rocket in half? Its maddening. The delay has NOTHING to due with what happen!

I think maybe you should learn how to build stronger rockets. No one else is having a problem but you.

 

[Tractionengines]

[ @AeroTech let me know if you want this removed or there are any corrections. ]

As Aerotech Noted in post #5621 (and elsewhere).

The plastic cap is removed, the charge can be adjusted and the cap replaced.

For reference here are the NOMINAL charges based on type. Use this for planing purposes, for when adjustments may be necessary

Quest 18mm Q-Jets have 0.25 gram ejection charges. EXCEPT the C & D motors with 4 second delays, which have 0.50 gram ejection charges.

Quest 24mm Q-Jets have 0.7 grams for D22W and E26W motors. ( Not sure of the E35 & F41 Q-Jets which are being release, but are not out yet. )

Aerotech SU 24 & 29mm Motors have .7 grams.

Aerotech DMS motors ship with 1.4 grams in the ejection charge kit.

Aerotech RMS reload kit charges:
18mm. .4 prams
24mm. .5 grams
29mm
29/40-120 Hobbyline .7 grams
29mm RMS HP-Style. 1.4 grams
38mm 2.1 grams

 

[sr205347d]

I am flying an RC rocket glider, so don't want an ejection charge. I would like to use a higher thrust E18 or F24 motor, rather than a slow-burn E6. It looks like I would have two options to plug them. One would be to use the regular 24/40 case and fill the ejection charge well with epoxy to plug it. The other would be to use the R/C 24/40 case.

Would there be any problem with these approaches?

Thanks.

Andy

 

[Antares JS]

I am flying an RC rocket glider, so don't want an ejection charge. I would like to use a higher thrust E18 or F24 motor, rather than a slow-burn E6. It looks like I would have two options to plug them. One would be to use the regular 24/40 case and fill the ejection charge well with epoxy to plug it. The other would be to use the R/C 24/40 case.

Would there be any problem with these approaches?

Thanks.

Andy

As long as you are using the delay element, it is unnecessary to fill the charge well of the 24/40 case with epoxy if you don't want an ejection charge. You can just put a piece of tape over the end.

 

[sr205347d]

That is what I thought, until it burned through and partially melted the depron motor mount.

 

[SolarYellow]

Maybe try aluminum tape meant for sealing HVAC ducting, available at big box hardware stores.

Could also stuff a ball of wadding or some dog barf under the tape or cap.

 

[Tractionengines]

Usually when I don't use the charge I put the Red Plug in anyhow. I don't remember ever seeing it pushed out/off.

I would think you could put a little wadding or dog barf in then the red plug, and a layer of tape over it. That would be more than enough Belt and Suspenders to keep the flame from the delay burn doing anything...there's no pressure behind it, so a little blockage, just makes sure any hot gasses go out the back of the nozzle...but YMMV

 

[sr205347d]

Maybe try aluminum tape meant for sealing HVAC ducting, available at big box hardware stores.

Could also stuff a ball of wadding or some dog barf under the tape or cap.

Yes, I had some wadding under the cap. Wasn't good enough. The red cap popped off, and the hot gasses also toasted my servo leads.

Is there any problem with using the R/C case with E18 or F24?

 

[Tractionengines]

They are cored grains.

The R/C loads are end-burners that don't expose the case end to much heat and pressure. I would think you need to add a forward insulator of some type to protect the case. IF it fits. That would make it a research motor though as you are changing parts.

 

[sr205347d]

They are cored grains.

The R/C loads are end-burners that don't expose the case end to much heat and pressure. I would think you need to add a forward insulator of some type to protect the case. IF it fits. That would make it a research motor though as you are changing parts.

That is a concern.

Given that, it looks like the epoxy plug is the way to go.

Thanks for the replies.

Andy

 

[smstachwick]

So perhaps we should be thinking of the C12 as a skinny C11, rather than a thrusty C5?

The Q-Jet packaging even says to compare to a C11, if memory serves.

 

[3stoogesrocketry]

That is what I thought, until it burned through and partially melted the depron motor mount.

A gentle coat of grease on the forward side if the delay element should prevent any more burning issues . If you look at the closure after assembly and you see a little bit of grease pushing thru the gas port hole, you put on the perfect amount of grease.

 

[Theory]

Flew my first K750 today.

Took my 21 pound 4” rocket to 2054 feet. Left the rail with authority!!! Well done Aerotech!!!

Up close and personal slow motion video:

 

[jimzcatz]

Is that the one grain 75 super thunder?

 

[StreuB1]

Is that the one grain 75 super thunder?

Sure is, Jim!!

I flew the first one around here (Illinois) at Bong the launch before Airfest. Was quite popular by everyone there.

Like the K1499N, it is the perfect motor for big rockets on challenging fields or cloud cover, or when you just don't want to go high.

Flew the same rocket on the K1499N at Bong last weekend and like the K750ST, it was sure a crowd pleaser!! An entire troop of cub scouts launching LPR's went absolutely bonkers when that W9 K motor hit. Not sure what was better, the kids reactions or the rockets flight itself!


Here is my flight on the K750ST from Bong. Picture courtesy of @rfjustin !!

 

[StreuB1]

Flew my first K750 today.

Took my 21 pound 4” rocket to 2054 feet. Left the rail with authority!!! Well done Aerotech!!!

Up close and personal slow motion video:



View attachment 539111

I knew you'd like it!