Titan IIIE

Inspired by the Estes 2019 kit. Modded for parallel staging and pop off boosters.

Almost ready to fly.

Is this a clone or a modified Estes kit? If it is not an Estes kit, how did you make the SRB nozzles?

BTW, nice model!! It would be great to see photos or a video of the pop-off SRB's in action.

Cool. What motors? . . . I see what looks to be and Estes motor with red ink in the center. Any details on booster separation, CP/CG, inquiring minds want to know!

It's a clone-ish. The SRB nose and tailcones and the decals are from excelsior rocketry. The core nose cone and transition are from the large Estes TARC set.

The booster motor mounts are 24mm. The core is 29mm. The F15-0 spent casing is just there as a stand so I can take photos.

I've only got OpenRocket, so I can't completely sim it. So I built a downscale version for 13mm motors and flew it with varying tail weight to figure out a safe CG.

More info over at YORF
https://www.oldrocketforum.com/showthread.php?t=15092
https://www.oldrocketforum.com/showthread.php?t=15120

Big 'un and ickle 'un.

Looks good

Beautiful!!!!

Niiiiice!

Based on the mini version, the CG needs to be at the bottom of the upper lugs.

The Lexan fins weigh a ton. She's going to need some nose weight.

I haven't decided if I'm going to try some core engine only flights first, or leap right in with something like E9+2xC11.

I say load her up max with motors and nose weight, you know where to balance her, and let her fly the way she was meant to fly. With good cluster techniques, a long rod, a big field and good weather, you should be fine.

One of my all time favorites and yours looks great! And I also suggest clustering it!

Verna
www.vernarockets.com
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The dry weight turned out to be 60g for each booster and 180g for the core.

If I put in 2xC11s and various motors from E9 to CTI G33, it takes 150g in the nose to put the CG where I think it should be.

That seems huge. I think the 1/8" Lexan fins are really hurting me, weight wise. I wish I new where the CP -really- was for this design.

Darn, stinking, performance robbing nose weight! It always takes more than you think or want, I hate it. So frustrating not to be able to get the solid answers you need. Huge and complex rocket science. The seemingly huge amount of nose weight just can't be right - it kills the efficiency of my rocket, I will just fly it with this much for my first complex rocket flight. . . CRASH!

I know they say it is a crutch but more power to lift the required nose weight will help. Say good bye to wimpy C11s and heavy, inefficient E9's. Hello D12-3s and an F-15-4. Make sure they all ignite at the same time! Good igniters, battery, wiring, maybe a good clip whip. Oh my, I have turned into a cluster Prima Dona! Trust in Thrust! It is just an ignition issue!

Darn wind! I came to fly this thing today and Lord help me I am going to do it! . . .CRASH!

It is simple math. Look at the chart and see if your motor combo can lift it safely. No overly complex science needed. Just lots of good common sense and a calm day.

Darn, stinking heavy Lexan! But it looks good and that is the most important. Maybe there is a way I can get rid of those awful fins?

Even with 150g noseweight, with the cluster there's plenty of thrust. Even if it only goes to 600ft. But man that cone seems heavy. I'll swap in a nylon chute.

I'm not _too_ bad about waiting for calm days. But it seems like it's always windier out on the runway at Bong than it was at home.

I love the look of the clear fins. Maybe I should have looked harder for 1/16", rather than 1/8". But would it be stiff enough?

I'm using 3/16" makrolon(lexan) for a 20# titan 2 that puts landing loads on the fins...so 1/8" for this does seem like overkill....and your fins aren't at the very bottom, or sticking down....As long as they don't break due to flex, I would think 1/16" would be fine, I don't think you are going to have flutter at this size...

Frank

Charles_McG said:

Even with 150g noseweight, with the cluster there's plenty of thrust. Even if it only goes to 600ft. But man that cone seems heavy. I'll swap in a nylon chute.

I'm not _too_ bad about waiting for calm days. But it seems like it's always windier out on the runway at Bong than it was at home.

I love the look of the clear fins. Maybe I should have looked harder for 1/16", rather than 1/8". But would it be stiff enough?

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I'll keep that in mind for the future. I got the 1/8" as scrap from the construction shop at work - the thinnest they had.

I'm reluctant to try and cut this set out. TTW and epoxy.

Charles_McG said:

Even with 150g noseweight, with the cluster there's plenty of thrust. Even if it only goes to 600ft. But man that cone seems heavy. I'll swap in a nylon chute.

I'm not _too_ bad about waiting for calm days. But it seems like it's always windier out on the runway at Bong than it was at home.

I love the look of the clear fins. Maybe I should have looked harder for 1/16", rather than 1/8". But would it be stiff enough?

Click to expand...

With some of my nose cones I use the very scientific belly laugh test. I hand someone at the club the heavy nose cone and if I get a good belly laugh I know I am good to go. Nose weight and power rule!

As for fins you will just have to experiment. So many factors to consider. If the weight penalty can be overcome then great, bulletproofing is awesome. If you are launching from a runway and there is nasty concrete to land on you can be sure your pretty scale rocket will want to land on it nice and hard. How much damage can you take? What is the repair investment in effort for the different thicknesses? Do you really need all that "finnage?" Fewer, smaller, lighter fins with peppier motors? Bigger, lighter chutes? So many variables, such complexity again!

If it flies too stable and one of the booster fins breaks off at landing, I would just give a good spit on the ground, break off the the other booster fin and fly it again.

You get it down to the razors edge, perfection and efficiency achieved, then you go to launch and the long rod you have always used is missing. Do you chance it on a short rod? Only then will you know. You are the man!

With three awesome BP motors you are not going to have fin flutter on this one. Even with three MPR composites I would worry more about the booster attachments. Fin flutter is for the High Power guys busting Mach, they talk the talk, they walk the walk. With whoosh poppers I would not be concerned unless the fins are thin cardboard poorly attached with a hot glue gun.

It looks really good btw, I really like the titan Centaur, flew my estes model a lot...Here's mine circa 1989 flying on an E-11 blackjack 24mm reload at the Boeing Kent space center where the BEMRC used to fly.

I don't see any fins on that one! Or is it lexan and trick 1989 photography?

You're right Charles, it would be a heavy nc but that's a trade off too. I've done several mods like that and they all have heavy nc's. Using a nylon chute would be good and that also adds a little weight. I'd also go with a 4', 3/16ths rod if you cluster it.

Since it's a clone, maybe you can do another one and make all the adjustments to the next one.

Verna
www.vernarockets.com
https://www.amazon.com/dp/B00HHJHOK6/?tag=skimlinks_replacement-20
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It's an optical illusion, the plug in fins were black, they just happened to line up with the dark background, that's why I love this picture...

Daddyisabar said:

I don't see any fins on that one! Or is it lexan and trick 1989 photography?

Click to expand...

burkefj said:

It's an optical illusion, the plug in fins were black, they just happened to line up with the dark background, that's why I love this picture...

Click to expand...

Back in "The Day" you had to have some luck. No photoshop, film based photography from some company called Kodak. Like Robinson Crusoe its primitive as can be.

It won't be long and they will say back in "The Day" they slowly hand built Titan model rockets from paper and plastic, with out active stabilization and rapid, on demand 3D printout.

I downloaded Rocksim and I'm reviewing the simming and my mini test flights. I made the core fins a bit larger on the final than on the mini prototype. I'm thinking I might be okay with 2-3oz, rather than 5. We'll see

And I'm set up for 1/4" rod.

I've got some bottling and kegging weekends before I can get in a test flight.

Charles_McG said:

I downloaded Rocksim and I'm reviewing the simming and my mini test flights. I made the core fins a bit larger on the final than on the mini prototype. I'm thinking I might be okay with 2-3oz, rather than 5. We'll see

And I'm set up for 1/4" rod.

I've got some bottling and kegging weekends before I can get in a test flight.

Click to expand...

Ditch the high labor bottles, get more and bigger kegs, then use the saved brewing time to launch your awesome scratch built rocket!

Charles_McG said:

View attachment 267823

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Oh yeah, that is almost as purdy as a bunch of big rocket motor casings!

I see now you are not talking simple home brewing.

Johnny Appleseed did not go around tossing apple seeds in order to make pie! The drink that built America! And will someday rule again! Prohibition tried its best to destroy the liquid gold and failed. The Feds also tried to destroy model rocket motors and failed. Cider and AP must fuel our favorite American pass times!

Daddyisabar said:

With whoosh poppers I would not be concerned unless the fins are thin cardboard poorly attached with a hot glue gun.

Click to expand...

You mean like they did in my younger son's after school program?

Here's the Rocksim. I'll check some of the measurements tonight - but this is close. It suggests about half the noseweight. Much less silly, sitting in the hand.

With all those fins pulling down the CP down you can lessen the nose weight, put it on a long rod and give it a test flight. My MR 171 flies with no nose weight and is fine if one of the outboard motors does not ignite or CATOS, both of which have happened.

You might want to do a side view model/sim and be sure you ok in that orientation as well.
Can skip the boosters and have the fins rotated 45 degrees.
Frank

Is that more of a visual check? Orientation doesn't seem to matter to Rocksim.