What G,H and I motors have long burns

I read on a website that there is a J90 motor - I think it is a 54 mm - that has a 7.9 sec burn time.

Is there anything comparable in burn time in the 38 mm casings for the G,H and I range?

The aerotech I59 has an 8 second burn time, according to thrust curve.
The I49 has a 7.7 second burn time.
The H45 has a 6 second burn time.

The CTI I216 burns fairly long (3 seconds), and above that, there's the aforementioned I59 and I69. There's also the Pro29 H54. The Loki I110 is pretty good too.

In the smaller sizes, there's not much for G motors, but the Apogee E6 and F10 burn for 8 seconds each.

And there's the 5+ second burning Quest D5....

The H45 is no longer made ( at least to my knowledge)...

It was a single use motor.
The I 132 was another nice long burn SU I motor.

JD

Aksrockets said:

The aerotech I59 has an 8 second burn time, according to thrust curve.
The I49 has a 7.7 second burn time.
The H45 has a 6 second burn time.

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Correct! It is a 54mm reload that goes in the 54mm x 852 case. It is used in conjunction with the extended forward closure. The J 180 also fit in that case; it's a C-slotted Blue Thunder load.


JD

dfos said:

I read on a website that there is a J90 motor - I think it is a 54 mm - that has a 7.9 sec burn time.

Is there anything comparable in burn time in the 38 mm casings for the G,H and I range?

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JDcluster said:

The H45 is no longer made ( at least to my knowledge)...

It was a single use motor.
The I 132 was another nice long burn SU I motor.

JD

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Dang. That in a cheap minimum diameter rocket would be great. Plus you dont have to worry about your casing getting lost.

cjl said:

In the smaller sizes, there's not much for G motors, but the Apogee E6 and F10 burn for 8 seconds each.

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There is the 8 second burn "G12" reload from Aerotech. Used in the 32mm "RC" casing (no ejection).

- George Gassaway

True enough. I omitted it because it's a non standard casing size, and has no ejection, but it could definitely be used (with the right rocket).

Look at thrust curves in the pdf aerotech catalog on their web site. There are a number of longer burning black jack reloads listed.

Ellis Mountain made some nice long burning motors such as a 6 second burn G20 and a 4 second burn G35 as well as several long burning H, I, J, K and L motors.

However since the owner, Robert Ellis passed away a few years ago, the supply of these motors have been steadily drying up.

terryg said:

Look at thrust curves in the pdf aerotech catalog on their web site. There are a number of longer burning black jack reloads listed.

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Yeah, the H 112 J and H73 J burn for about 3.5 sec.

The I49N and I59 WN are tons of fun.

I flew an I49 in a modfied a Semroc SLS Hustler last month to 5500 ft... was very cool.

Keep in mind that the I49 and I59 are boost-sustain and do not have motor ejection. You must use electronics with these motors.

The J90 is going to go in a Mongoose 54 as soon as I get around to building it.

The I110 is a great long burn - may be tricky getting them for now - until Scott ramps up production.

I still have a few G 35's somewhere....

They are a pain to get an igniter into.


JD

BEC said:

And there's the 5+ second burning Quest D5....

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so a quest D5 burns twice as long as a D 12 but both engines deliver the same total thrust? how do they get a D to burn so slow?

Besides the H54, Cesaroni also makes the G54, which is basically the same motor except with a slightly higher initial thrust and 8Ns less total impulse.

Rocket_Man said:

so a quest D5 burns twice as long as a D 12 but both engines deliver the same total thrust? how do they get a D to burn so slow?

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The casing for the D engine is a long, 20mm (not 18mm) tube. it is 3.7in long (about the length of an E9) with end burning motors, the length of the burn is determined by the length of the casing, the average thrust is determined by the diameter of the case (a c11 burns quicker then a C6) With composite motors this is exactly the opposite. this is why a 38mm H burns longer then a 29mm H.

I've been making and flying 38 mm I85 motors for years. 580 N-s, 7 sec burn, fits Aerotech 38/720 case. Hopefully, a commercial manufacturer will make a similar motor as it's feasible from the 100 or so I've burned over the years with no failures. Attached is a pic of my rocket boosting on one.



View attachment d720a.bmp

It might be due to a few things...Although I've never done BP motors; They could use a larger nozzle, denser propellant, or a slower burning formula.



JD

Rocket_Man said:

so a quest D5 burns twice as long as a D 12 but both engines deliver the same total thrust? how do they get a D to burn so slow?

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I'd guess it's the same formula, and the longer burn is simply due to the longer motor.

Don't forget the Kosdon I130. Such a sweet motor. Some vendors may still have some.

I saw an AT J135 at our last launch and it was amazing. I looked it up after the launch and I think it was a 6.8 second burn. It seemed like forever and was simply cool to see. I now own one. . . .

Sandy.

There are quite a few long burn 54 mm motors. In 38 mm, I've not seen any with longer than 4 second burn (except the previously mentioned EX I85).

Rocketjunkie said:

There are quite a few long burn 54 mm motors. In 38 mm, I've not seen any with longer than 4 second burn (except the previously mentioned EX I85).

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The I59 and I49 are longer than that, aren't they?

cjl said:

The I59 and I49 are longer than that, aren't they?

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You got me there - end burners. Wish there was a warp 9 speed propellant with smoke