Neubauer 4in. GEMINI TITAN Kit

[BRC]

I am about to embark on a Neubauer 4in. GEMINI TITAN Kit that appears to require a G80-4T engine..Being new at this, come someone suggest an equivalent to the G80-4T as they appear to be discontinued.....Thanks !!!

[GregGleason]

... [can] someone suggest an equivalent to the G80-4T ...

My substitute would be a G78G (https://www.discountrocketry.com/aerotech-single-use-motors/aerotech-g784g-single-rocket-motor-p-2163.html) . It has a similar thrust curve as the G80T, but not as robust. The G78G does have a 4 sec delay.

Try the G78G in the altitude simulator of your choice and see if it meets your performance objectives.

Greg

[Royatl]

I am about to embark on a Neubauer 4in. GEMINI TITAN Kit that appears to require a G80-4T engine..Being new at this, come someone suggest an equivalent to the G80-4T as they appear to be discontinued.....Thanks !!!


I don't think they've been discontinued, as they were re-done just last year with great fanfare to increase their total impulse from 109 (after previously being lowered a few years ago from 120) to 137 ns.

(EDIT) Oh, I see what you mean. The four second delay indeed has been discontinued, probably due to the extra impulse making a longer delay desirable. It is entirely possible that the Neubauer GT will fly just fine on a seven second delay.

(EDIT again) And I would agree with Greg, that the G78 would be the motor closest in performance to the old G80-4 (in fact, I would go with any of the G77,78, or 79 motors -- just pick your plume color)

[BRC]

Thanks guys !! :D

[Bravo52]

PLEASE PLEASE PLEASE do a build post..........I want to see one built.

[BRC]

PLEASE PLEASE PLEASE do a build post..........I want to see one built.


Ill do it..!!!! It was ordered today, my wife is taking my mother-in-law on a flight to a family re-union, leaving me home with my two sheperds and a Gemini TiTan to build (2nd week of August )...I even took that week off to build it !!! :chuckle:

[BRC]

Another question for you rocket scientists (heheh) ...Would a G79-7W work with this Gemini or is a 7 second delay too much...
I have been demo(ing) Rocksim with this motor but cannot get it to simulate properly on my Mac..

[GregGleason]

Would a G79-7W work with this Gemini or is a 7 second delay too much...


My "gut" feel is that it is too much and that you should back away from that and go with a 4 sec delay. If this was a lightweight and streamlined 3" rocket then you might get away with it. But the Gemini has a big OD and a blunt nose, both of which are aerodynamically draggy and are going to slow it down after motor burnout. If you never have built this size before then you will be surprised at how much the weight it can put on, since there is so much surface area. For example, painting a few coats of white from a spray can onto a 16" length of 2.6" airframe w/ fins took the weight from 738 to 755 grams.

Typically it is better to size the motor after you build the project of this size, so you have a pretty good idea of the weight. Now if you had 2 motors in it you might want to go with the 7 sec delay.

It should be a lot of fun to build and turn heads at the launch sight.

Greg

[BRC]

My "gut" feel is that it is too much and that you should back away from that and go with a 4 sec delay. If this was a lightweight and streamlined 3" rocket then you might get away with it. But the Gemini has a big OD and a blunt nose, both of which are aerodynamically draggy and are going to slow it down after motor burnout. If you never have built this size before then you will be surprised at how much the weight it can put on, since there is so much surface area. For example, painting a few coats of white from a spray can onto a 16" length of 2.6" airframe w/ fins took the weight from 738 to 755 grams.

Typically it is better to size the motor after you build the project of this size, so you have a pretty good idea of the weight. Now if you had 2 motors in it you might want to go with the 7 sec delay.

It should be a lot of fun to build and turn heads at the launch sight.

Greg



Thanks Greg...The motors I would like to have G79-4W is on backorder from just about everybody..But I wont need it for awhile... :D

[BRC]

Ill do it..!!!! It was ordered today, my wife is taking my mother-in-law on a flight to a family re-union, leaving me home with my two sheperds and a Gemini TiTan to build (2nd week of August )...I even took that week off to build it !!! :chuckle:


How time flys !!! I am all done with her...Took plenty of Pics to do a build thingy..Awaiting the engine and still have to build a launch pad..Great ideas for that on these forums..Still stuck on lugs or rail..I have never seen one up close and asked somewhere for someone to post a pic of both the rail and the button?? on the rockets side to see how it is attached...Here is a pic of the finished product that I had posted on this forum, but another conversation...

http://www.oldrocketforum.com/attachment.php?attachmentid=16046

[Bravo52]

How time flys !!! I am all done with her...Took plenty of Pics to do a build thingy..Awaiting the engine and still have to build a launch pad..Great ideas for that on these forums..Still stuck on lugs or rail..I have never seen one up close and asked somewhere for someone to post a pic of both the rail and the button?? on the rockets side to see how it is attached...Here is a pic of the finished product that I had posted on this forum, but another conversation...

http://www.oldrocketforum.com/attachment.php?attachmentid=16046

That's a great looking picture. Nice job. How about some detial shots! Capsule, Motors, Fins.....ect....

[BRC]

That's a great looking picture. Nice job. How about some detial shots! Capsule, Motors, Fins.....ect....

Motor is still enroute...Will take and post close-up(s) tomorrow...

[Bravo52]

Will take and post close-up(s) tomorrow...

How is the build coming???? I would really love to see some pictures! I'm interested in the kit myself.

[BRC]

Ready to fly !! Probably next weekend ..Will post some pics tonight !! Wish I had some decals for the capsule tho ...

[BRC]

Went out with the Tripoli Tampa Launch Group today and had a great time..Here is the launch of my Gemini Titan... :D
oops too big...Will try later.....