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29/180 with RAS for g54 29/100 won't fit

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BTharpe

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Hey All -

Newbie question here. I'm trying to assemble my 29/180 casing with two (the short two) spacers to fit a G54 which works with a 29/100.

I don't think the nozzle is pointing out as far as it should and that's causing everything else to not fit in the tube.

Am I doing some sort of newbie mistake here?

I'll attach some pictures to hopefully show what I'm talking about.
IMG_20200102_211548.jpg
IMG_20200102_211508.jpg

I would expect in this picture below for a good fit that the nozzle would squeeze into the aft closure slightly?
IMG_20200102_211437.jpg


Thanks!
Bryan
 

llickteig1

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I believe the nozzle sits on the aft closure as pictured except that there is a 1/16" o-ring that should be between the closure and the nozzle. Obviously, the closures should both screw down snugly.

I can't find documentation which spaces(s) to use - it is in the assembly instructions? I don't have 29mm RAS (I own all 29mm size cases) so i can't compare.

HTH, --Lance.
 

CzTeacherMan

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Spacers... If you're using the two short spacers, I'm not sure that's correct for the 100 reload. Try different configurations of spacers (long and short) and you'll get it
 

Eric

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I don't think the R.A.S. works with the 29/100 case. Its an odd size. All the others are 60ns increments. The short spacer is just for use with the 29/360. So you 180 case can go to 120 or 60, with one and two spacers, respectively.
 

BTharpe

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Well then... That would explain a lot.

I saw on the apogee website that it would go down to 100, but 60, 120, 180 makes much more sense all being multiples of 60.

Whommp. Guess I have some random white lightning grains to use creatively?

Thanks for the quick responses!

Screenshot_20200102-230250.jpeg
 

solid_fuel

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Whommp. Guess I have some random white lightning grains to use creatively?
Where do you fly? I have a 29/100 case that I would let you use if you clean it well when you're finished. ask around at your club there is probably some one who can lend you that case. although the 29/100 case is not widely used
 

BTharpe

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Im in Dallas. Planning to go to the Gunter launch in Jan.
Where do you fly? I have a 29/100 case that I would let you use if you clean it well when you're finished. ask around at your club there is probably some one who can lend you that case. although the 29/100 case is not widely used
That's a good point, I'll see if anyone out there has a 29/100.

I took a picture of a grain from the 29/100 vs a 29/180 grain and the spacers and sizing make much more sense now!

Spacer == 60 off of a 29mm reload. The 180 grain is on the right

Thanks all for the newbie help [emoji16]
IMG_20200103_082645~2.jpeg
 

Buckeye

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Well then... That would explain a lot.

I saw on the apogee website that it would go down to 100, but 60, 120, 180 makes much more sense all being multiples of 60.

Whommp. Guess I have some random white lightning grains to use creatively?

Thanks for the quick responses!

View attachment 402550
Here we go again. Nice try by Apogee to lend some insight to these spacers, but this table is incomplete and outright wrong. Maybe I will drop them a line to fix it. At least 2 of us made incorrect decisions from it. Too bad AT doesn't have a proper table to help users understand their spacer system combinations.

https://www.rocketryforum.com/threads/what-is-a-grain.156793/#post-1949328
 

BTharpe

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mikec

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Aerotech has been around for a long time and has a very diverse collection of reloads and hardware, with a few oddballs that use special forward closures (endburning and long-burning), special aft closures (54mm "small nozzle" aft closure), or non-standard case lengths. The RAS doesn't play well with those situations and you tripped over one. I agree that Aerotech could document the RAS situation better. I've always found it useful to check out the instructions for a given reload on the Aerotech website (not that this would have helped your specific problem). http://aerotech-rocketry.com/resources.aspx?id=4
 

llickteig1

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Aerotech should have a matrix for reload/case/adapter configurations on their web-site, IMO.

And the vendors should link to it from their reload pages. There is just so much stuff to try to be aware of and try to remember.

My gut was telling me the 29/100 was an odd duck but i couldn't find anything to confirm that. I'm glad someone did.

I also have a 29/100 if you ever come to Argonia.
 

JDcluster

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The 29 mm x 100 hardware has been around for quite some time. Just to give you an idea; I flew a G 104 back in 1997.
 

BTharpe

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Agreed, a matrix from aerotech would be great!
 

dinoburb

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I have a question on motors that are in cases larger than the original design using spacers. Is the effective motor power reduced by the excess space provided by the spacers?
 

Eric

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R.A.S. doesn't change the performance at all. The forward closure is floating and goes bellow the spacers.
 

dhbarr

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With the added weight aft, for most birds you'll slightly decrease stability. For stubbies you could actually increase it if your casing extends substantially past the CG.

More inert mass always means a slower top speed. More mass also usually means lower total altitude, but sometimes higher ( think wiffleball vs. shotput ).

Assuming you don't change your recovery system the descent rate & landing speed will also be faster. Other than that performance should be unaffected.
 
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grouch

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Gunter huh? It's a shame this didn't come up several months ago as I have a couple of 100 cases I could have lent you but I am no longer in the DFW area. You might want to keep an eye for one and pick it up if you come across, the G104 is a fun motor to burn.
 

dinoburb

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Thanks Eric. I didn’t realize the foreword closure floats and is actually below the spacers, there by creating a functionally smaller case!
 

BTharpe

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Gunter huh? It's a shame this didn't come up several months ago as I have a couple of 100 cases I could have lent you but I am no longer in the DFW area. You might want to keep an eye for one and pick it up if you come across, the G104 is a fun motor to burn.
I'll keep a lookout for one for sure
 

pyrobob

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Pretty sure DARS has a loaner case in this size. They have many.
 

Rocketjunkie

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To get a 29/100 reload to fit, you need to use a liner 3.548" long. 3-9/16" will work. You can get liners at rocketmotorparts.com (https://www.rocketmotorparts.com/Paper_Motor_Liner_29mm/p1577809_7795909.aspx) This is the size for a 29/120. Use 1 spacer. (Replace the 29/100 liner with the longer liner. Use like a 29/40-120 reload with the space at the top.) You should have the rest of the needed parts in the reload kit.
 

swatkat

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I used one spacer in the 29/180 to fly the 29/120 G25 reload this weekend. worked perfectly, The 29/100 loads won't work with the system as the grain for that reload is an odd size.
 

Rocketjunkie

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I used one spacer in the 29/180 to fly the 29/120 G25 reload this weekend. worked perfectly, The 29/100 loads won't work with the system as the grain for that reload is an odd size.
That is why you need the longer liner referenced in my previous post. This makes the reload the same length as a 29/120. You will have some empty space in the liner like the 29/40-120 in the reloads less than G.
 

DeltaVee

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It seems to me that that the 29mm RAS (using one spacer) will allow a 29/60 reload to work in the 29/120 case... however on at least one vendor website (whose name escapes me right now), it states that the RAS is for the 29/180 or larger motor.

Has anyone tried a 29/60 reload in the 29/120 casing?
 

grouch

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There is no reason why it shouldn't. Apogee's information also shows it can be done.
 
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