# Rouse Tech 75mm Boat Tail Closure

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#### ChrisAttebery

##### Well-Known Member
I have a brand new Rouse Tech 75mm Boat Tail Closure for sale. I bought it to use with an M685 but it isn't compatible with the medusa nozzles used on the long burn 75mm motors.

I'm asking $125 shipped which is what I paid for it in February. Thanks, Chris #### ColumbiaNX01 ##### Red blooded white American male I have a brand new Rouse Tech 75mm Boat Tail Closure for sale. I bought it to use with an M685 but it isn't compatible with the medusa nozzles used on the long burn 75mm motors. I'm asking$125 shipped which is what I paid for it in February.

Thanks,

Chris

I know this page is from 2012 but did these sell for 74 bucks new?

https://forum.ausrocketry.com/viewtopic.php?f=21&t=3608

#### GRIFFIN

##### Well-Known Member
Five years of inflation.

#### ChrisAttebery

##### Well-Known Member
It really doesn't matter what it cost new. This is the free market in action. These are out of production and nobody that I could find has them in stock anymore. Just like NOS classic car parts.

I'm asking WHAT I PAID for it 7 months ago. I'm not making a cent on this deal.

#### ColumbiaNX01

##### Red blooded white American male
Last I checked Rouse Tech ceased production a couple years ago. These things are relatively scarce. Chris says he paid \$125 for it. The list price when they were still in production is irrelevant.
I guess that is true. Stuff is only worth what people would pay for it.

#### blackjack2564

##### Crazy Jim's Gone Banana's
TRF Supporter
Yes they did retail for 80 bucks, I bought one from the last run Rouse did, direct. So yes that WAS the actual retail, but so what....lol
Like a dumb ass, I sold [new, never used] it for 55.00 last year, not knowing I had one of the last ones made.
Nor how much they were commanding shortly there after. It does not matter what one pays for something......it's what the current market will bear.

Sale pending...

#### kevinkal

##### Insatiable Hobbyist
Get the dimensions on it before you ship.. so when you put that NC lathe next to your mill.. you'll be set. =]

#### MarkH

##### ---
If you are going for max altitude in 75mm, this closure isn't all that useful with Aerotech's motor selection. I mean, you could use the boat tail on the M1850W in the 7680 case, but the M685 is going to go higher in the same case, withiut this closure, since the closure is not compatible with the M685.

If AT would produce a 75/10240 case and could eek out both an N and a full M, in the same case, similar to the M1500 and L2200 both in the 75/5120 case, using this closure, they would be on to something. Keeping the average thrust in the low 2000 range.

#### ColumbiaNX01

##### Red blooded white American male
If you are going for max altitude in 75mm, this closure isn't all that useful with Aerotech's motor selection. I mean, you could use the boat tail on the M1850W in the 7680 case, but the M685 is going to go higher in the same case, withiut this closure, since the closure is not compatible with the M685.

If AT would produce a 75/10240 case and could eek out both an N and a full M, in the same case, similar to the M1500 and L2200 both in the 75/5120 case, using this closure, they would be on to something. Keeping the average thrust in the low 2000 range.
Mark, so ur saying a low thrust but high impulse motor like m or n is the best option when using a 75mm boat tail. But as is aerotech does not have that option.

#### ChrisAttebery

##### Well-Known Member
That sums it up nicely. I had read/heard that AT was replacing ALL of the 75mm medusa nozzles with single throat nozzles. Apparently that doesn't apply to the long burn motors, or at least not yet.

If you are going for max altitude in 75mm, this closure isn't all that useful with Aerotech's motor selection. I mean, you could use the boat tail on the M1850W in the 7680 case, but the M685 is going to go higher in the same case, withiut this closure, since the closure is not compatible with the M685.

If AT would produce a 75/10240 case and could eek out both an N and a full M, in the same case, similar to the M1500 and L2200 both in the 75/5120 case, using this closure, they would be on to something. Keeping the average thrust in the low 2000 range.

#### MarkH

##### ---
Mark, so ur saying a low thrust but high impulse motor like m or n is the best option when using a 75mm boat tail. But as is aerotech does not have that option.
Yes, in 4, 5, or 6 grain case the moonburners are going to go higher than the others, but the closure can't be used on the moonburnrers, because they use medusa nozzles.

The full M and baby N reference (if AT made such motors in 75mm) could be record attempt motors, and using the boat tail closure on them would be even better.

#### ChrisAttebery

##### Well-Known Member
Nice to see you lurking here Mark.

#### MarkH

##### ---
Nice to see you lurking here Mark.
Yes I do check in now and then.

Good luck with your flights at XPRS.

#### jondub

##### Well-Known Member
I contacted Karl at ST recently about the plan to replace Medusa nozzles with single throat nozzles. Not happening anytime soon. Was planning for that with an M685 at XPRS but alas, my hopes are dashed.

#### ColumbiaNX01

##### Red blooded white American male
I contacted Karl at ST recently about the plan to replace Medusa nozzles with single throat nozzles. Not happening anytime soon. Was planning for that with an M685 at XPRS but alas, my hopes are dashed.

Whats ST????

Staff member
TRF Supporter
Global Mod

#### MarkH

##### ---
I contacted Karl at ST recently about the plan to replace Medusa nozzles with single throat nozzles. Not happening anytime soon. Was planning for that with an M685 at XPRS but alas, my hopes are dashed.
It will still go plenty high with the regular closure. Here is one I flew a couple years ago:

#### ChrisAttebery

##### Well-Known Member
Man, that was a squirrelly launch.

#### MarkH

##### ---
Yeah, if you pause it, you can see it boosted straight out of the tower but did a wiggle about 50 ft up. Probably was due to small-ish fins combined with the offcenter core of the moonburner. That's Tony's dog Rocket barking in the background.

#### ChrisAttebery

##### Well-Known Member
Actually it looks a lot like my L265 flight from 2015. It took off straight too, then about 50 feet up it took a 5-10 degree turn, after that it was straight until burnout.