7.5 inch diameter BLUE TUBE on a O3400

Just wondering what you guys think. A half scale patriot that is 7.5 inches in diameter on an O3400. I love blue tube and I have used it lots of times. I love fiberglass, but blue tube is lighter. I already have an O3400. I am just exploring my options. I know I could probably use full length couplers and basically double up the airframe wall. What are your thoughts.

I see no reason not to go ahead. Good luck.

Making your own glassed tubes is cheaper and more rewarding. You can also go with reinforcing the blue tube with two wraps of 6oz. glass and it should be fine.

SinfulDarkLord said:

Making your own glassed tubes is cheaper and more rewarding. You can also go with reinforcing the blue tube with two wraps of 6oz. glass and it should be fine.

Click to expand...

Whatever. It will be fine as is.

SinfulDarkLord said:

Making your own glassed tubes is cheaper and more rewarding. You can also go with reinforcing the blue tube with two wraps of 6oz. glass and it should be fine.

Click to expand...

It is however on a 7.5" tube its probably just more time consuming which may be worth the $$ to buy tubes. Like Jim said blue tube will be fine.

SinfulDarkLord said:

Making your own glassed tubes is cheaper and more rewarding. You can also go with reinforcing the blue tube with two wraps of 6oz. glass and it should be fine.

Click to expand...

For this size of project making my own tubes would be to time consuming and expensive. The cost of epoxy, peel ply, breather fabric, and vacuum bagging would cost outrages amounts compared to just ordering tubes from alwaysreadyrocketry.com

The O-3400 is a beast motor.
Were it I.........would use the full length couplers. Cheap way to guarantee success on an expensive project like this.

Also would either glass the inside of coupler/av-bay, or fit another section of coupler inside, by slicing it & removing a section.

I'll definitely be keeping an eye on this project. Good luck!

andrewlathrop87 said:

For this size of project making my own tubes would be to time consuming and expensive. The cost of epoxy, peel ply, breather fabric, and vacuum bagging would cost outrages amounts compared to just ordering tubes from alwaysreadyrocketry.com

Click to expand...

You dont have to go as far as vacumm bagging. Besides, my only doubts is no reinforcement. Alone I suspect it will get destroyed. The O-3400 is not to be taken likely just like the N-5800.

SinfulDarkLord said:

You dont have to go as far as vacumm bagging. Besides, my only doubts is no reinforcement. Alone I suspect it will get destroyed. The O-3400 is not to be taken likely just like the N-5800.

Click to expand...

I know what the O3400 offers, I have flown that motor before. If it is worth doing its worth overdoing. If your taking the time to do tip to tip why the hell not vacuum bag!!!!!

How old are you? What is your experience with big motors?

andrewlathrop87 said:

I know what the O3400 offers, I have flown that motor before. If it is worth doing its worth overdoing. If your taking the time to do tip to tip why the hell not vacuum bag!!!!!

How old are you? What is your experience with big motors?

Click to expand...

I dont have no experience, but I aint blind to everything else. Its common sense if the N-5800 has destroyed countless rockets even with advanced composite work (I will include metal) it is likely that the O-3400 will take down a blue tube with no reinforcement. I'd rather be assured than having it destroyed. Even as Jim stated using full length couplers to beef it up is not a bad option either.

It's flat stupid to fly a O3400 on the cheap. If you can't afford the rocket, don't fly the motor.

lawndartman said:

It's flat stupid to fly a O3400 on the cheap. If you can't afford the rocket, don't fly the motor.

Click to expand...

very good most if not all people know that. People get what they pay for. No one said they were gonna fly a O3400 in a Blue Tube rocket. That is what is great about this site people can share their thoughts and ideas. Nothing is set in stone.

SinfulDarkLord said:

I dont have no experience, but I aint blind to everything else. Its common sense if the N-5800 has destroyed countless rockets even with advanced composite work (I will include metal) it is likely that the O-3400 will take down a blue tube with no reinforcement. I'd rather be assured than having it destroyed. Even as Jim stated using full length couplers to beef it up is not a bad option either.

Click to expand...

You are correct. No one is flying a N5800 in this thread. No one is going for a min diam in this thread. Simply sharing thoughts. If you want to talk min diameter go to a min diameter thread.

Might be interesting to see what the load specs of the tubing is compared with the load created by this motor ? Might give you insight to what steps in reinforcing that you may want to do .

This isn't a project I would tackle.... but then again, I've not flown anything that big. I look forward to seeing how you do it!


Later!

--Coop

Andrew, You know I've flown the O3400 a few times, Personally I'd just go with G12 and guarantee your success, Excluding any other type of mishap that is.

I say do it. I love BlueTube, and I wish more people would jump on-board. Hey, you might even be able to get Dave from Always Ready Rocketry to sponsor your build as a way to showcase his product!

Rocketry was and still is about pushing boundaries to learn and excel. Go for it! If you don't, I'm sure someone will come later and try it anyway, so it might as well be you.

455 Buick has a great point! Go for it!

I say go for it. Crazy Jim's stiffener idea is a good one. Are those fins in your ORK file to scale? They look a little odd to me.

It's not an extreme flight due to the 7.7" BT diameter, and the 68 pound weight. It's fairly draggy so the peak acceleration is only 15 G.

I would have 2 concerns: 1.) Potential for column bucking of the airframe near max V. I don't think that's an issue with the large diameter airframe and certainly a double wall, full length coupler airframe would be sufficient if it was, but may not be necessary; and 2.) Potential for fin flutter near max V. Again, in the concept of keeping it cheap and light, just performing the fin flutter calculations to make sure the fins are stiff/thick enough.

A rather cool way to do a 4 mile flight with an O.

Bob

andrewlathrop87 said:

View attachment 262002

Click to expand...

I've been following this thread for both my interest on how you'll implement the O3400 w/ BT, and also because of the whole shpeal with Alexander and that previous thread that got locked.

Now I am also more on the inexperienced side in regards to working on L3 level rockets, but I am not providing advice on how to do so. However, when I see something that troubles me, it feels unjust to leave it as is.

I respect you and your work Andrew, as I do with all the other rocket builders out there, but I think this went and is going from making a point to someone and making them learn their lesson to the sole purpose of public shaming and "winning" against Alexander. If we were to follow the true "maturity" and "non-naive" aspects that others have mentioned, this incident would just be a laugh for you and your friends and could be dealt with privately (in relation to Alexander). In exposing it all like this, it puts Alexander in bad light for however long people remember this and/or bring it up, makes people also possibly look down upon you for exposing the Private Messages (however that is up to you if you care about what others think), and finally may discourage those looking on from wanting to part of this community, as the only thing they see here is hostility and being publicly shamed for providing advice that was swatted away.

Now I am not defending Alexander, nor do I know him, but he is also at fault for different reasons as many have stated in the locked thread. Both sides were disrespecting the other, but its time to move on.

Hopefully my advice on the non-building related issue may help you in some way.

Thanks for reading, and good luck with your building! I'll be following closely!

Alexis Thoeny

Fair is fair. Agreed!!

If you have flown with BlueTube, you know what it can do. My max is an L265 in a 3" and 4x38's (mid K) in a 4" BT Kraken. I have seen them come apart, they don't zipper, they unwind, etc. I have seen them fall from 1 mile high and bounce on the desert floor with scratches. Yeah. If you have used Blue Tube, you know what kind of animal it is.

You have flown multiple far larger motors, with a variety of materials. If you say you think you will be fine, it is your choice, your rocket and your experience.

Go for it!!

The full length coupler idea is a good one though.