Aerotech L850W

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shp1255

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I don't own a rocket motor sim but would like to know if it is safe to use a single throat nozzle instead of a medusa nozzle on the Aerotech L850W?
 
I don't own a rocket motor sim but would like to know if it is safe to use a single throat nozzle instead of a medusa nozzle on the Aerotech L850W?

Why in the world would you do that? Just use the nozzle that comes in the reload kit.

Now that I think about it, if you change the nozzle to something other than what comes in the kit you will void the warranty and take a pretty big risk with a rather expensive case and probably a rather expensive rocket as well. If you don't get the throat exactly right...it'll be either a "HOLY CRAP IT'S A LAND SHARK RUN" or a KAH-BLAMMO.

-Dave
 
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It would be safe to do if you :

Knew the correct equivalent size.

Had that size nozzle manufactured to fit that case.

Flee it at a research launch and flowed safe distance.

.....but I agree, why would you want to alter the design of the original load?

The Aerotech K700 (and others?)was available with not a single throat and a medusa style nozzle. Aerotech can manufacture one nozzle and depending upon what load it is for, the nozzles are drilled with either 2,4 or 6 holes. It is a great system for a manufacturer. Seems impractical to modify as a hobby enthusiast.
 
In theory, yes - but your throat dimensions would have to be the same.

The Aerotech K700 (and others?)was available with not a single throat and a medusa style nozzle. Aerotech can manufacture one nozzle and depending upon what load it is for, the nozzles are drilled with either 2,4 or 6 holes. It is a great system for a manufacturer. Seems impractical to modify as a hobby enthusiast.
The K700W as well as (I think) everything else in 54/2560 uses a single-throat.
 
The K700W as well as (I think) everything else in 54/2560 uses a single-throat.

"Uses" is relative to a time line. I can show you 2 different K700's from my stock with 2 different nozzle styles. They once used the medusa nozzle.
 
I don't own a rocket motor sim but would like to know if it is safe to use a single throat nozzle instead of a medusa nozzle on the Aerotech L850W?

You would be better off submitting that question to Aerotech. Then you would know for sure. They would even sell you the correct one if it's missing.
 
"Uses" is relative to a time line. I can show you 2 different K700's from my stock with 2 different nozzle styles. They once used the medusa nozzle.
Yes, I was referring to newer motors. I think the K550W once used a Medusa nozzle as well?
 
Here's another thought...you change nozzles and alter the chamber pressure technically it isn't certified anymore because it will perform differently. That means you aren't supposed to fly it at a tripoli or NAR launch...
 
Based on Tony's link I guess it still is. I'll pull a J415 to take a closer look and confirm.
 
Yes it will work . 2 months ago I flew a Aerotech 4 grain 75 millimeter L 1170 fj as a 3 grain motor. I used a snap ring case with a standard graphite nozzle . The expected chamber pressure was right about the same as the four grain motor . Check your numbers . It will be a ex motor . The one I flew turned into a 3000 ns L750 .
Eric
 
Okay, the J315R, J460T, J415W, and J540R all have madussa nozzles. The J800T and K695R have a single throat nozzle. I've got the other reloads on the way and will check as they turn up.
 
Okay, the J315R, J460T, J415W, and J540R all have madussa nozzles. The J800T and K695R have a single throat nozzle. I've got the other reloads on the way and will check as they turn up.
I THINK the K185W is the only 54/1706 reload that uses a Medusa nozzle. Everything else (and above) in 54mm uses a single-throat.
I also believe that the J800T is the only 54/1280 reload that uses a single-throat.
 
I THINK the K185W is the only 54/1706 reload that uses a Medusa nozzle. Everything else (and above) in 54mm uses a single-throat.
I also believe that the J800T is the only 54/1280 reload that uses a single-throat.

I have seen a k550 with a Medusa nozzle, but I don't know when it was manufactured.
 
I THINK the K185W is the only 54/1706 reload that uses a Medusa nozzle. Everything else (and above) in 54mm uses a single-throat.
I also believe that the J800T is the only 54/1280 reload that uses a single-throat.

I figured someone would notice that the J800T appears to be the only 1280 reload with a single throat nozzle. Not sure why that is but perhaps they can interchange depending on their inventory?
 
I believe the J1799N (1280 case) uses a single-throat nozzle. The J1299N (for the 852 case) definitely does.

David
 
I figured someone would notice that the J800T appears to be the only 1280 reload with a single throat nozzle. Not sure why that is but perhaps they can interchange depending on their inventory?
You think I wouldn't notice that. ;)
 
I figured someone would notice that the J800T appears to be the only 1280 reload with a single throat nozzle. Not sure why that is but perhaps they can interchange depending on their inventory?

Most of the J800's I've seen were Medusa nozzles though...
 
They must be interchanging them based on inventory at the time the reloads is packaged?
 
I THINK the K185W is the only 54/1706 reload that uses a Medusa nozzle. Everything else (and above) in 54mm uses a single-throat.
I also believe that the J800T is the only 54/1280 reload that uses a single-throat.

I was about to build up a J800T-L and I downloaded the Aerotech J800T Assembly Drawing for it. It shows the Medusa Nozzel. When I saw this I was concerned, since the nozzle in my reload bag is a large single throat. I found your post doing a search. This gives me some confidence that my reload kit wasn't mis packaged.
 
Aerotech themselves recommend using a single throat nozzle for medusa reloads in Cesaroni hardware, so it clearly works. Other than that situation, I would be hesitant to go back and forth without seeing some numbers or talking to someone with direct experience.

Enjoy that L850, by the way. It is an absolutely gorgeous burn and one of my favorite motors.
 
I was about to build up a J800T-L and I downloaded the Aerotech J800T Assembly Drawing for it. It shows the Medusa Nozzel. When I saw this I was concerned, since the nozzle in my reload bag is a large single throat. I found your post doing a search. This gives me some confidence that my reload kit wasn't mis packaged.

I flew an Aerotech J800T last year at LDRS with a single throat nozzle and it worked perfectly. I wouldn't worry about it.
 
Aerotech used to use the medusa nozzle on all of their 54mm and 75mm motors. When the redlines were first introduced, there were some problems with the K695 and K1275 blowing nozzles iirc. The single throat was introduced for those motors. Sometime between '04 and '06 the rest of the 54/1706 and above loads started shipping with them as well as the 75/5120 and above loads. I believe the J800T may have been a little bit later though, because I've used a lot of medusa J800's.

It probably boils down to reliability. The more holes that are open on the medusa nozzle, the greater the chance of it letting go. So if the corresponding nozzle throat dia is large enough to use the single throat, then it has been switched over by now. Most of the 1706 K loads use an undrilled single throat nozzle.
 
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