any 18 mm motors larger than D

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dfos

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I am making a 18 mm minimum diameter rocket that would be able to take a motor larger than a D if it exists. Do any companies make 18 mm's that are larger than D -- like longer than 70 mm?
 
not anymore unfortunately. aerotech used to have a 18mm E for the reloadable case, but sales were low so they cancelled it :(
 
same length, but there was only a 4 second delay available due to the length/intensity of the burn
 
Oh, well I guess that wouldn't have worked anyways. I would need a much longer delay on this rocket. funny they aren't made. I would think they would be popular.
 
dfos said:
Oh, well I guess that wouldn't have worked anyways. I would need a much longer delay on this rocket. funny they aren't made. I would think they would be popular.
Click to expand...

The sales numbers were low for this reload along with the 'B' and 'C' reloads. :(
 
Initiator001 said:
The sales numbers were low for this reload along with the 'B' and 'C' reloads. :(
Click to expand...

seems like a B or C could be fit into a 13mm casing, though the price for them would be horrible for anyone but a contest flyer :O
 
Maybe if CTI makes Pro18 motors in the future. They came out with some pretty crazy stuff in the Pro24 series :eyepop:
 
Aerotech used to make E45 (40 N-s) and F55 (50 N-s) motors but it's been about 15 years since they made them. Still have a couple of each :D The E45 is 4-3/16" long, the F is an inch longer. Delays were 4, 8, or 12 seconds.

Might be a good time to look into 18 mm Rx motors. I already make reloadable C and D 13 mm motors. The picture is the D.

D40 Hi cnv.jpg

View attachment d40d.bmp
 
Green Monkey Aerospace makes 13mm, 18mm, & 24mm research hardware. I'm sure you can put together something. They have 18mm motor tubes up to 7.75" long.

I didn't post the link because my bit defender anti-virus put this on the top of their page when I went to it.
BitDefender 2011

This web page has been blocked by BitDefender Antivirus Real-time Protection!

The web page blocked by BitDefender included objects that were either infected or likely to be infected with a virus. Your system has NOT been infected.
Click to expand...
 
dfos said:
I would think they would be popular.
Click to expand...

I think there are gobs of people out there who would have the instant, "knee-jerk" reaction something like COOL, I want one!

Then, a second later, they all realize there is no place to launch something like that with any chance of recovering it, and it would be too expensive to just launch on a one-way flight simply for the thrill of it all.
 
I've still got an old Aerotech 18mm E in the rangebox. It was a single use and the same size as their 18mm Ds. I don't remember the specs but I do remember it is a 4 sec. delay.
 
JAL3 said:
I've still got an old Aerotech 18mm E in the rangebox. It was a single use and the same size as their 18mm Ds. I don't remember the specs but I do remember it is a 4 sec. delay.
Click to expand...
E25. 22 N-s, just a glorified D21 :wink:
 
The 18x70mm Es were barely Es and I think that is why they did not sell that well. The short delays limited the rockets they could be flown in.

The E45 and F55 were really cool but they were "outlaw" motors. I remember being told that I would not be allowed to fly them at a sanctioned launch. I used the last of mine 17 years ago?
 
JPVegh said:
The 18x70mm Es were barely Es and I think that is why they did not sell that well. The short delays limited the rockets they could be flown in.

The E45 and F55 were really cool but they were "outlaw" motors. I remember being told that I would not be allowed to fly them at a sanctioned launch. I used the last of mine 17 years ago?
Click to expand...

The E25 single use motors were available in 4, 7, and 10 second delays. It is the E27 reload that was only available in a 4 second delay. Either the E25-4 or E27-4 were good motors for low flights in Aerotech's 1.9 inch diameter kits. The E45 and F55 motors would be good motors. However, it is easier to use a larger diameter motor mount for rockets that would fly well on those longer 18mm composites and adapt down.
 
Now an E reload for the 18mm case. I could really go for that but the last time I got something from Aero-Tech was we will see. Maybe.

Andrew
 
Since this thread has probably attracted a bunch of 18mm guys could anyone PM me the inside dimension of a rouse tech or aerotech 18mm case.
 
I’ve launched a BT-50 sized rocket using an 18mm reload AeroTech D24 and that thing practically teleported off the launch rod. Even using a streamer for recovery and with no wind to speak of. . .Write of? I had a long, long walk to recover it

Put one of those into an even smaller lighter weight rocket and you’d need “Superman Vision” to keep track of it.
 
it's a 24mm motor but I've got one remaining G42, which I think was Gary's way of getting rid of remainder grain sections that were left after making E15 motors. They were dirt cheap but only available every once in a while, as I remember.

Initiator001, is that the correct origin story, and is that also the story for the E45 and F55 (and the G55, which I also had one of and used to destroy a FlisKits Thing-a-ma-Jig three years ago!)?
 
While I get the point why not start by showing there is support for 24mm reloads that are full, or near full E, F, and G's? Buy some Pro24. I'd bet a tenner that in a few years Pro24 is gone. We in the community claim we want X, Y, and Z but we don't put our money up.

There are wild 24mm reloads. Right now. CTI is making them. Want 18's? Show there is a MARKET for small reloads.

So says me who HAS bought Pro24.
 
gdjsky01 said:
While I get the point why not start by showing there is support for 24mm reloads that are full, or near full E, F, and G's? Buy some Pro24. I'd bet a tenner that in a few years Pro24 is gone. We in the community claim we want X, Y, and Z but we don't put our money up.

There are wild 24mm reloads. Right now. CTI is making them. Want 18's? Show there is a MARKET for small reloads.

So says me who HAS bought Pro24.
Click to expand...

a bit high and mighty and fully off topic, not to sound too offensive. I agree support what is out there when you can, but the op was simply asking if there are larger 18mm loads for an 18mm md rocket he is not building a 24mm rocket. I believe if anything shows market interest it would be buying more at 18mm reloads rather than buying cti 24 hoping that it would eventually show cti or at that they need bigger 18mm stuff. To further discuss this plz create a new thread or pm, there is no need to threadjack. Iirc didnt cti come out with the pro24xl around the time a kit came out that happened to be a 24mm md...

Back to addressing the op. There are 18mm research cases available if you feel somewhat comfortable with doing it yourself. I have been wanting to do an 18mm md rocket for a while, and also looking at getting into research motors. I may have to pick up a few cases myself. good luck and keep us updated.
 
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gagreen said:
a bit high and mighty and fully off topic, not to sound too offensive. I agree support what is out there when you can, but the op was simply asking if there are larger 18mm loads for an 18mm md rocket he is not building a 24mm rocket. I believe if anything shows market interest it would be buying more at 18mm reloads rather than buying cti 24 hoping that it would eventually show cti or at that they need bigger 18mm stuff. To further discuss this plz create a new thread or pm, there is no need to threadjack. Iirc didnt cti come out with the pro24xl around the time a kit came out that happened to be a 24mm md...

Back to addressing the op. There are 18mm research cases available if you feel somewhat comfortable with doing it yourself. I have been wanting to do an 18mm md rocket for a while, and also looking at getting into research motors. I may have to pick up a few cases myself. good luck and keep us updated.
Click to expand...
However there are real limitations on what you can do with an 18 mm casing.

The bore of a propellant grain is a duct that conducts hot gas to the nozzle throat. As the length to bore diameter get larger, the higher thegas velocoty gets over the last propellant grain. At some point, the velocity gets high enough to initiate eerosive burning which can cause a multitude of problems such as over pressurization and liner spitting. Both phenomenon can cause a cato, or at minimum, very strange and unpredictable thrust curves. To avoid this, the bore ID much be increase if the propellant is lengthened. When this point is reached, the thrust increased due the increased burning area, but the total impulse flattens or decreases as the total mass of propellant either remains constant or actually decreases as the bore get larger. Since is costs money to process a propellant grain, excessively long motors of small diameters cost significantly more than shorter but fatter motors which perform better, and thus there is no commercial market for really long skinny motors.

See the referenced thread for details. https://www.rocketryforum.com/showthread.php?t=22616

Bob
 
OK Jeff, when is an E not an E? When a G is high power? I am totally confused. Wasn't the E reload an E24? Or somewhere around there? Wouldn't that make the Estes E9, just a bit more than a D?

Inquiring minds want to know.

Andrew
 
A G can be HP if it has:
More than 62.5 grams of propellant,
Is sparky,
or has an average thrust of over 80 newtons.
 
accooper said:
OK Jeff, when is an E not an E? When a G is high power? I am totally confused. Wasn't the E reload an E24? Or somewhere around there? Wouldn't that make the Estes E9, just a bit more than a D?

Inquiring minds want to know.

Andrew
Click to expand...

The Estes E9 is long and will not fit in an older rocket with the normal 2.75" long D12 sized motor clip. And E9 would stick out the back, shift the c.g. aft and in certain models (like a Phoenix missile) it will make the model unstable.The E9 is about 150% of the total-impulse of a D12.
 
I am not sure how much more punch would be possible in the small 18mm case. Warp 9 might give more impulse, but without reliable ejection delays it would have limited use (dual deploy in an 18mm rocket any one?).
 

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