38mm Deuce's Wild

ok, so I have flown my 18mm deuce 3 times, cracked a fin and needs repaired. Flew my 29mm deuce 4 times ready for its fifth time this time full DD. Now I am ready to start getting parts together for a 38mm Deuce's Wild!

This rocket will be built similiars to Carl T's. I am using LOC 4" tube with some 5oz FG on it. I will also do a 10degree cant on the motor tubes. This will allow me about 14 or 15" of motor. The fins will be 1/4" plywood with through the wall tabs t2t'd with 6oz FG. I will have sandman make me a nosecone. I am thinking foam with 2 layers of 3oz FG. I am hoping to keep this thing under 5.5lbs to get a 5:1 thrust ratio with 2 G61's. If I can keep it at 6.1lbs it will be at a 4:1. With the massive fins this thing has I feel comfortable with a 4:1. Pics will come as I do work. I am laying out the support triangle, fins, and CR's tomorrow.

Ben

May I suggest not using a support triangle?

I found with my 54mm deuce that the best way to do the larger deuce mounts is simply the centering rings with the motor tubes manually inserted and aligned. it should be a nice rocket though - much more doable for you than the 75mm

I've seen several upscale Deuce's with the cant angle set to 10 degrees so that more motor choices would be available, but I gotta tell you it just isn't the same

15 degrees really *does* look so much cooler...

Sounds cool. What happened to the 8" Patriot?

jflis said:

I've seen several upscale Deuce's with the cant angle set to 10 degrees so that more motor choices would be available, but I gotta tell you it just isn't the same

15 degrees really *does* look so much cooler...

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I am still planning and I think I can do 12 degrees with 14" not the same but closer!

cjl: I am going to put one in because in my 29mm I found it harder to keep them aligned with 2 CR's. and I do not think a 3rd one will do much either. I can always change things as I go along.

Ben

jflis said:

I've seen several upscale Deuce's with the cant angle set to 10 degrees so that more motor choices would be available, but I gotta tell you it just isn't the same

15 degrees really *does* look so much cooler...

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I don't know - you do get pretty good flame/smoke separation with 10 degrees between the motors...

Mine is done slightly differently though, so even though the angle is only about 9.5 degrees, there is a lot of space between the motors...

jflis said:

I've seen several upscale Deuce's with the cant angle set to 10 degrees so that more motor choices would be available, but I gotta tell you it just isn't the same

15 degrees really *does* look so much cooler...

Click to expand...

If you make the angle 10 degrees, then move the point of intersection further up the rocket the best of both worlds will be attainable. If you did it right the distance between the ends of the motor tubes would be identical in both cases make the flame/smoke seperation nearly identical but in the 10 degree rocket longer motors will be possible.

Of course the flames won't be as close to horizontal but I doubt the difference will be that noticable.

Plus you get more usable thrust.

Ryan S. said:

Plus you get more usable thrust.

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Doesn't reducing the angle result in less stable flight if one motor doesn't light?

No.

If anything, it should be slightly more stable, though it shouldn't honestly matter very much.

cjl said:

No.

If anything, it should be slightly more stable, though it shouldn't honestly matter very much.

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Really? I thought the canted angle was what made the duce so stable with a single engine. I know I have read that somewhere...

Maybe my confusion is this: Where is the angle measured? From vertical with vertical being 0 degrees or from horizontal with vertical being 90 degrees. If the former then I stand by my confusion.

from vertical. Theirfore the closer it is to zero the more power you have.

Ben

uncle_vanya said:

Really? I thought the canted angle was what made the duce so stable with a single engine. I know I have read that somewhere...

Maybe my confusion is this: Where is the angle measured? From vertical with vertical being 0 degrees or from horizontal with vertical being 90 degrees. If the former then I stand by my confusion.

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It's from the vertical. The reason that it doesn't really matter is that the lower angled motor also has its thrust closer to the centerline of the rocket. Because of this, the angle really doesn't make any difference in the performance of the rocket, other than that a smaller angle gives you slightly more usable thrust. A good example of this taken to the extreme is that larger rockets with clusters can be perfectly stable if only some of the motors go, even though the motors are canted at 0 degrees (perfectly inline with the rocket).

If anything the canted angle will make it less stable as the angle introduces a force vector normal to the rocket's airframe.

I beleive the reason it flies straight is a combination of factors including the CP CG relationship and the point the motor's thrust exerts force.

Ryan S. said:

If anything the canted angle will make it less stable as the angle introduces a force vector normal to the rocket's airframe.

I beleive the reason it flies straight is a combination of factors including the CP CG relationship and the point the motor's thrust exerts force.

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Unless the canted angle is vectored through the CG.

Actually, the optimum (since the CG moves forward during flight) would be to have it slightly rearward of the CG at launch so that it moves towards and past the CG during flight.

A canted motor configuration is the only configuration where you *can* have the thrust vectored right through the CG.

[NASCAR fan = ON]

cjl said:

A good example of this taken to the extreme is that larger rockets with clusters can be perfectly stable if only some of the motors go, even though the motors are canted at 0 degrees (perfectly inline with the rocket).

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No, no. That's just slight of hand.

Ryan S. said:

I beleive the reason it flies straight is a combination of factors including the CP CG relationship and the point the motor's thrust exerts force.

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That's magic.

[NASCAR fan = OFF]

Anyway... best of luck with your project Ben and keep us updated with plenty of photos.

been a while. I actaully have not moved any farther forward with this. :cry: I am working on finishing up other ones before I get this one any farther. I have been doing some drawing and I think I will use the support triangle with upper and lower Cr's just like the origional. I am going to make this electronic deploy only. I will go with a zipperless design. I am hoping to get around to this but if I don't its #2 on my list to use my Xmas money on (first is a CD3 unit)

Ben

ben said:

I am hoping to get around to this but if I don't its #2 on my list to use my Xmas money on (first is a CD3 unit)

Ben

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and rocsim

rocketkyle said:

and rocsim

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yes. My dad said he would pay 1/2 of it since he thinks its something good to have but it is so darn spensive!

Ben

ben said:

but if I don't its #2 on my list to use my Xmas money on (first is a CD3 unit)

Ben

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Just curious, what rockets have you built that would even slightly warrant the use of CO2?

ben said:

yes. My dad said he would pay 1/2 of it since he thinks its something good to have but it is so darn spensive!

Ben

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Just buy it.


It's well worth it, and if your dad is paying half of it, it's no more than many video games (and a heck of a lot more useful). I bought my copy right after V8.0 came out.

cjl said:

Just buy it.


It's well worth it, and if your dad is paying half of it, it's no more than many video games (and a heck of a lot more useful). I bought my copy right after V8.0 came out.

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true and i don't have a system so it don't matter to me

Ben

ben said:

yes. My dad said he would pay 1/2 of it since he thinks its something good to have but it is so darn spensive!

Ben

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Ben, Ben, Ben...
Rocksim should have been one of your first investments...that and some extra hardware that you typically use in your cluster projects.

Afterall...you just ante-d up for one huge Saturn V multi motor flight, and it will all go up in smoke in an afternoon.

RockSim you will use for the entire time in the hobby.

MaxQ said:

Ben, Ben, Ben...
Rocksim should have been one of your first investments...that and some extra hardware that you typically use in your cluster projects.

Afterall...you just ante-d up for one huge Saturn V multi motor flight, and it will all go up in smoke in an afternoon.

RockSim you will use for the entire time in the hobby.

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I am thinking about (trying) to sell 2 of the 54mm 2 grain cases. Its worth it, and I will get some more hardware so I don't have to borrow (I know you like to hear that!!).

Ben

ben said:

I am thinking about (trying) to sell 2 of the 54mm 2 grain cases. Its worth it, and I will get some more hardware so I don't have to borrow (I know you like to hear that!!).

Ben

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Not that 54mm I saw recently is it?
That nice grey one?

ben said:

yes. My dad said he would pay 1/2 of it since he thinks its something good to have but it is so darn spensive!

Ben

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You dont have rocsim?


You built an 8" rockit and you dont have rocsim??????????????


You know whats going to be darn expensive? When your rocket crashes because you didn't simulate it.

Ryan S. said:

You dont have rocsim?


You built an 8" rockit and you dont have rocsim??????????????

You know whats going to be darn expensive? When your rocket crashes because you didn't simulate it.

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Well now, wait a minute... You're making it sound like rocsim *created* high power rocketry. It sounds like, before rocsim it must have been impossible to design, build and successfully fly a high power (or perhaps *any*) rocket.

That just isn't so. Rocsim is a great tool, don't get me wrong. However, under NO circumstances is it a required tool to build and design rockets.

I hope you realize that the Saturn V moon rocket was designed with the help of little more than a glorified calculator...

jflis said:

I hope you realize that the Saturn V moon rocket was designed with the help of little more than a glorified calculator...

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Really? I thought they used one big cardboard cutout. :tomato:

jflis said:

Well now, wait a minute... You're making it sound like rocsim *created* high power rocketry. It sounds like, before rocsim it must have been impossible to design, build and successfully fly a high power (or perhaps *any*) rocket.

That just isn't so. Rocsim is a great tool, don't get me wrong. However, under NO circumstances is it a required tool to build and design rockets.

I hope you realize that the Saturn V moon rocket was designed with the help of little more than a glorified calculator...

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By scientists and people with degrees, who had experience building smaller (ish?) rockets. Not by kids with no experienc what-so-ever in their backyard.

Yeah you can build rockets without rocsim but why not utilize the tools you have if they are available. If Ben had done this he would have realized making the fins on his Patriot bigger would have made his life easier.

Sure I could cut all the wood to build my house with a hand saw, but why when I can just grab a chop saw and make the job half the work.

Ryan S. said:

By scientists and people with degrees, who had experience building smaller (ish?) rockets. Not by kids with no experienc what-so-ever in their backyard.

Yeah you can build rockets without rocsim but why not utilize the tools you have if they are available. If Ben had done this he would have realized making the fins on his Patriot bigger would have made his life easier.

Sure I could cut all the wood to build my house with a hand saw, but why when I can just grab a chop saw and make the job half the work.

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wow you and Todd must be like 2 peas in a pod! Ok, like I said to him, when you build a Scale rocket you use scale size fins, BT, nosecone. If I wanted a sport scale rocket I would have made the fins bigger. I do not need rocsim to tell me that I need noseweight. I use a borrowman calculator spreadsheet found here https://my.execpc.com/~culp/rockets/Barrowman.html at the bottom to figure out how much. Once I get it in its flight ready stage will I find out how much noseweight I need.

And I downloaded the demo for the patriot. But I don't even know the final weight so what is rocsim going to do for me? I already knew I needed about 10-12lbs of noseweight. Without the nosecone finished and and parachute none of those figures are set in stone. Again rocsim.....no help, unless it can get me an 8" 22" long nosecone and 17' patachute.......

Ben