T12 FTCs

[Blenderite]

I have a 4' FTC rocket that doesn't have a recovery system. So far I have launched about 4 times at 120 psi each time. All 4 times it landed in a field, drastically bent. I re-pressurized them and they straightened out perfectly. I bought 3 extra 8' T12 FTC yesterday. Lowe's still had a good stock of them. The T8 seems to be too small for rockets. I doubt that a release system could be used with T8. I suppose it would have to back glide.

[Nick B]

yeah,

set them up for backglide or chute and you will enjoy them more. T8s are more sturdy for RnD to get your methods sorted out, then 4 foot t12s and up.

There are narrow chute systems for the t12s and you can put larger nose sections on the t8s for recovery.

Once you get the touch for properly balancing and backgliding your FTCs you can get a 8 foot FTC with a onboard cam and a jolly logic, to drop down to the ground and land like a feather.

It's a beautiful thang.

[Asupremeflight]

yeah,

set them up for backglide or chute and you will enjoy them more. T8s are more sturdy for RnD to get your methods sorted out, then 4 foot t12s and up.

There are narrow chute systems for the t12s and you can put larger nose sections on the t8s for recovery.

Once you get the touch for properly balancing and backgliding your FTCs you can get a 8 foot FTC with a onboard cam and a jolly logic, to drop down to the ground and land like a feather.

It's a beautiful thang.

Is the secret to backgliding in the placement of the fins? Let's say I were to wrap a 4 ft t12 with glass tape which makes it heavier. Can I still set it up for backgliding? How do I know where to place the fins to create this effect? Does the size of the fins matter? I thought I read somewhere that backgliding is not always what happens no matter how you set it up.

I made a really nice plunger to fit into a T12 with electronics the whole kit and caboodle and that crashed. ( I think the g's created at 150 psi disconnected a wire.) it worked at 100 psi but due to the weight of the mech and the electronics it did not go high at all. I was bummed because it was a real slick mech reduced to rubble. I have not abandoned that method but I am in search of lighter alternatives.

[Nick B]

Is the secret to backgliding in the placement of the fins? Let's say I were to wrap a 4 ft t12 with glass tape which makes it heavier. Can I still set it up for backgliding? How do I know where to place the fins to create this effect? Does the size of the fins matter? I thought I read somewhere that backgliding is not always what happens no matter how you set it up.

I made a really nice plunger to fit into a T12 with electronics the whole kit and caboodle and that crashed. ( I think the g's created at 150 psi disconnected a wire.) it worked at 100 psi but due to the weight of the mech and the electronics it did not go high at all. I was bummed because it was a real slick mech reduced to rubble. I have not abandoned that method but I am in search of lighter alternatives.

not really. It's more a matter of fin size fin drag, and the rockets balance CG which you want farther back to backglide. How far back depends on the rocket. Yes, you can get a wrapped, heavier rocket to backglide. USWR has or had a backglider in their fleet.

Backgliding takes some experimenting with weight, fins and balance. Use a smaller rocket to get a feel for the adjusting. Backgliding is only problematic when your design is flawed, the weight has changed, it is too windy. You are adjusting the rockets wind resistance and balance while dropping horizontally. As the wind kicks it around, it will knock the rocket around and upset the glide balance, making the rocket dive nose or tail first, until the balance is restored on it's own with air resistance.

[Blenderite]

I have thought of backgliding, I just have not been able to find a site that gives a good explanation of it. Does anyone know of any like that?

[Nick B]

I have thought of backgliding, I just have not been able to find a site that gives a good explanation of it. Does anyone know of any like that?

Not sure by memory, but I think George's site does, Robert Youens, Yahoo groups along with a few others. Even a few conventional model rocketry sites using flammables like gunpowder or Kno3. Some give simple explanations, some give detailed explanations and diagrams with terms like center of mass, center of pressure, etc.



In the end tho, It all depends how to adapt your rocket designs make it happen.

[Asupremeflight]

could it be as simple as putting some weight close to the fins. something like a ring of plastic or even a ring of tape wrapped several times in order to bring the CG toward the bottom?
I can move my fins freely and put them where I want. If I were to move the fins up on the rocket a little that might work too.

[Nick B]

could it be as simple as putting some weight close to the fins. something like a ring of plastic or even a ring of tape wrapped several times in order to bring the CG toward the bottom?
I can move my fins freely and put them where I want. If I were to move the fins up on the rocket a little that might work too.

yes.

I have my.... 3......small............fins per ftc rocket, placed roughly 3 to 5 inches up from the bottom bulkhead leading edge. This gives me room to fine tune the weight to the bottom of the rockets, adjust fin size, mount the rocket to heavier grade o rings or tapered seals by getting a better grip on the rocket during launch tube/rocket insertion, add avionics to the bottom of the rocket instead of the top if needed, and get a better unobstructed view of the lower bulkhead function under pressure. You can add weight with tape or other material as you see fit. All my ftcs have this config, backgliding or using chutes.

[Nick B]

Or.........

you could just put a brass gardenia nozzle on the bottom and need bigger fins to keep it from punching a hole in your driveway....

[Blenderite]

I will be testing this recovery system very soon!

[Nick B]

just to touch on this again...

best to practice with a t8 or t12 4 footer before an 8 footer






that aside.........





just picked up 4 more t8s

they do seem thinner.......


dirty evil faceless greedy profit monger capitalist share holder board of director bastids......





but I also picked up an old used one that is unusually thick........

[Nick B]

Addendum:

After closer inspection, the current Lithonia FTCs in both t8 and t12 are marginally thinner and less stiff than the previous ones I already have, bought only two years ago.
I dont know about the other manufacturers, but they probably also executed the same cost saving tactics. This dynamic likely offsets most existing data here and at other sites and web pages, as far as pressure limits per temperature, before and after mods.


buyer beware.

[U.S. Water Rockets1]

I crashed an 8 foot T12 yesterday and it crushed horribly. Got home and noticed that the bulkhead had no cracks so I filled it with air and it straightened out and held air. I was surprised. This is an FTC from Westinghouse. Not sure of the wall thickness but I would imagine it is the same everywhere.

They all crush like that when you crash them. They even squash if they crash in the water. Nothing you can do about it, because the diameter is so thin compared to the length.

[Nick B]

just scored sum westinghouse t12s. They are thicker than the others.

[Blenderite]

Where did you get them Nick B?