Dual E Estes CC Express Mod Project

[Green Jello]

In another thread you guys were recommending the CC Express as a great two stage rocket. I saw it's on sale today at HobbyLinc, so I ordered one:

http://www.hobbylinc.com/htm/est/est1302.htm

Now my question is this. How do you build it so it can take dual E engines instead of dual D? Since the Estes E engines are 1" longer is it really possible?

Image Credit: SCIGS30


-----------------------------------------------------------------------------------------------------------------------------------------------------
UPDATE


Ok...I've been playing around and here is the design I came up with (I think):



CC Express Mod.ork

Here are the changes:

1. Lengthened the booster stage body tube to accomodate E size engines
2. Lengthened the sustainer stage motor mount to accomodate an E size engines.
3. Shortened the main body tube by 2" (from 18" to 16")
4. Changed the overall fin design for looks and aerodynamics
5. Added side tubes to house streamer recovery for booster stage.

I haven't started yet, so I'm not married to any of this, but I think it's what I'm going to go with. The side tubes are modeled with large launch lugs because Open Rocket can't do tube fins. I'm going to do them with BT-20 tubes that house streamers and they will be capped off with these nose cones from SEMROC:



What do you guys think?

[Green Jello]

Also, does anyone have a link to the instructions on this guy? I can't seem to find them anywhere.

Also an Open Rocket file?

[bradycros]

The Estes web site has a great many of the instruction sheets for their kits available at no cost. Look it up, it's there.

[Green Jello]

The Estes web site has a great many of the instruction sheets for their kits available at no cost. Look it up, it's there.

I of course checked there first. Like I said, I can't find them.

Edit. Ok, I R DUM.

http://www.estesrockets.com/media/in...CC_EXPRESS.pdf

[AfterBurners]

I of course checked there first. Like I said, I can't find them.

Edit. Ok, I R DUM.

http://www.estesrockets.com/media/in...CC_EXPRESS.pdf

You're not dumb just takes time to know where to look? A lot of the things you ask can be found if you do a little leg work. Converting the rocket to an "E" would require a longer engine tube of 1" for both the sub-stainer and booster and not looking at the kit you would probably have to get a piece BT-55 and increase the length of it to accommodate the longer tube.

[Green Jello]

Yeah, after looking at this for a while, I think I'll make the booster stage longer to accommodate an E and run it as E12-0, D12-7. That should be plenty to lose it on the first launch.

[chadrog]

You only want to fly it once? Edit- You beat me to it, glad you understand.

[MarkH]

In another thread you guys were recommending the CC Express as a great two stage rocket. I saw it's on sale today at HobbyLinc, so I ordered one:

http://www.hobbylinc.com/htm/est/est1302.htm

Now my question is this. How do you build it so it can take dual E engines instead of dual D? Since the Estes E engines are 1" longer is it really possible?

Image Credit: SCIGS30

Move the engine block forward in the top/ sustainer stage to accomodate the longer E. Tape both engines together, and friction fit into the sustainer first. For the booster stage, friction fit it also, letting the booster engine extend out the back the extra inch. I believe the kit comes with an engine block for the booster stage as well that goes in the aft end of the booster to retain the engine. Leave the booster stage engine block out.

[Green Jello]

Does anyone have an Open Rocket file of the CC Express?

[AfterBurners]

Does anyone have an Open Rocket file of the CC Express?

I have it ROCKSIM'ed if it helps... shoot me a PM if I can help you out

[plano-doug]

Move the engine block forward in the top/ sustainer stage to accomodate the longer E.

That will require a longer motor tube. Instead, he can leave out the block and let the motor hang out on the forward end. For a thrust ring, three wraps of ¼" masking tape on the aft end of the sustainer motor works fine.

But I like this approach, Mark. No new parts are required. The bird can be made into an E-E Express without ordering new stuff.

Tape both engines together, and friction fit into the sustainer first. For the booster stage, friction fit it also, letting the booster engine extend out the back the extra inch.

Yes, I agree. Just let the motor hang out aft. I'm pretty sure there's plenty of stability margin. (But it wouldn't hurt to sim it, just in case )

I believe the kit comes with an engine block for the booster stage as well that goes in the aft end of the booster to retain the engine. Leave the booster stage engine block out.

This can result in a fried booster if the booster stage doesn't kick with the motor. I've seen it too many times. The heat softens the friction tape on the booster motor just enough that it slides out leaving the booster stage stuck on the sustainer motor, which fries it like burnt toast.

As a work around, here's what I do. I recess the booster motor tube, then put a tape ring (3 wraps) around the forward end of the booster motor. That way, when the booster motor separates, it drags the booster stage with it. (The pic is for the 2nd stage of my Farside clone, but it applies to any booster stage that lacks positive motor retention.)

Doug



.

[Green Jello]

Ok....So I built the stock CC Express in Open Rocket. I partly did this as a base for the mods I'm going to do to it, and I partly did it to learn Open Rocket and improve my skills there.

Now can one of you who know Open Rocket well, explain to me why this thing is only reading 556' on a dual D12 setup?

Thanks.

[AfterBurners]

I don't have OR but it sounds like the altitude in feet??

[JPVegh]

Ok....So I built the stock CC Express in Open Rocket. I partly did this as a base for the mods I'm going to do to it, and I partly did it to learn Open Rocket and improve my skills there.

Now can one of you who know Open Rocket well, explain to me why this thing is only reading 556' on a dual D12 setup?

Thanks.

Change the booster motor from a D12-7 to a D12-0 and change the booster fin material to balsa. Also the nose cone is too thick and should be polystyrene.

[Green Jello]

Change the booster motor from a D12-7 to a D12-0 and change the booster fin material to balsa. Also the nose cone is too thick and should be polystyrene.

Thanks. Well, that helped, but it's still only 883'. :/

[Green Jello]

Up to 1412' on the latest version. (I keep finding errors, but I think it's right now)

[Pat.H]

Why do you want to dual E stage the rocket?
you could go for an E sustainer stage and a D booster stage quite easily
and if you want to go higher you could just remove a fin like this:

CC ExpressV1.2 .ork

[Wayco]

I went and looked at my CC Express, and I did move the sustainer thrust ring forward to accommodate an E motor, but since they didn't have an E booster motor at that time, mine uses the D12-0 for the booster. I considered making the booster a little longer, but with the fincan in my hands, I noticed that every one of the four fins on that booster had cracks at the base. Even with a D motor, that booster is too heavy for tumble recovery. If you put an E motor in it, you will constantly be repairing it unless you design some sort of recovery system that will slow it's descent. My rocket with a D12-0/E9-8 motor combination will fly out of sight in a clear sky, the only reason I have recovered it is the excellent launch area we have in Rainbow Valley, AZ. I probably will fly it with an E12-8, but I'm gonna watch it with my binoculars when I do!

[Green Jello]

I never really considered having a larger engine for the second stage. I was thinking about modding the booster stage to take an E and making it streamer recovery, and then having a D for the second stage.

I live in the desert and have a huge flat launch area, so I'm not all that concerned about losing it.

[plano-doug]

[FONT=comic sans ms][SIZE=3]... I noticed that every one of the four fins on that booster had cracks at the base. Even with a D motor, that booster is too heavy for tumble recovery. If you put an E motor in it, you will constantly be repairing it unless you design some sort of recovery system that will slow it's descent.

That's a good point. But I'd be inclined to over-size the fins rather than add a streamer. That's less complicated and probably more reliable.

Regardless, I know from flying hundreds of stagers, that broken booster fins are part of the deal. If the ground is too dry and hard, or if the bird simply lands wrong, you can get broken fins on just about anything. I usually just glue them back together and keep flying 'em. Only rarely do I actually refinish a broken fin. Makes it sort of a rat rod rocket

Doug

.

[Wayco]

I've had a long standing love affair with two-stage rockets, starting with my first build, the Estes Mongoose. After many crimped body tubes from the booster coming in ballistic, I made a slight change. I put the very durable plastic fin can in the middle of the body tube, now it tumbles just fine. My second two stage is a Apogee Rip-Roar, and it has been glued back together so many times it's overweight! Can't fly it safely on a D12-0, so I built a cluster booster 2x24mm that I'm hoping will work. One D12-0 and a D12-3 that ejects a small parachute after separation.
The CC Express might benefit from a fireproof streamer rolled up in the space at the top of the booster, but it would be "iffy" just hoping it would deploy and I can't figure a way to insure that it would. Oh well, guess I will just super glue cracked fins again this season and repaint it annually while it's too hot to fly rockets. (Like now)
Green Jello, you should definitely make room in your sustainer for an "E" motor, this rocket is awesome on an E9-8, and I'm looking forward to trying the new E12's too.

[Green Jello]

Green Jello, you should definitely make room in your sustainer for an "E" motor, this rocket is awesome on an E9-8, and I'm looking forward to trying the new E12's too.

After playing around a bunch, I think I've decided to lengthen the booster stage and make it so it can take a dual E, but I'll generally run it on something like E12-0, D12-7. It's really funny how terrible the fins are on this model according to Open Rocket. You can change their profile just about any way and they are more efficient. Was Estes trying to make the CC Express not go as high?

[JPVegh]

After playing around a bunch, I think I've decided to lengthen the booster stage and make it so it can take a dual E, but I'll generally run it on something like E12-0, D12-7. It's really funny how terrible the fins are on this model according to Open Rocket. You can change their profile just about any way and they are more efficient. Was Estes trying to make the CC Express not go as high?

The CC Express goes plenty high as designed.

I think Estes leans more towards stability, safety and ease of construction than performance in most cases, which is as it should be.

I also tend to think that too much emphasis is placed on higher and faster in model rocketry but then it could be that I'm getting old, my eye sight is going bad and I don't like taking long walks in the hot sun. I'll leave higher and faster to the young pups, this old dog has done that trick.

[awseiger]

Was Estes trying to make the CC Express not go as high?

Probably... Mine used to go out of sight, single staged on an E9....

[Green Jello]

Interesting. Here are the projected elevations from Open Rocket:

D12-0; D12-7 = 2,039'
E9-0; D12-7 = 2,478'
D12-0; E9-8 = 2,685'
E12-0; E12-8 = 2,831'
E12-0; E9-8 = 3,098'

Of course there is no such thing as a E9-0.

[JPVegh]

What does it show for an E12-0 to an E9-8?

[Green Jello]

What does it show for an E12-0 to an E9-8?

Woah...glad you asked.

E12-0; E9-8 = 3,098'

[Green Jello]

Ok...I've been playing around and here is the design I came up with (I think):



CC Express Mod.ork

Here are the changes:

1. Lengthened the booster stage body tube to accomodate E size engines
2. Lengthened the sustainer stage motor mount to accomodate an E size engines.
3. Shortened the main body tube by 2" (from 18" to 16")
4. Changed the overall fin design for looks and aerodynamics
5. Added side tubes to house streamer recovery for booster stage.

I haven't started yet, so I'm not married to any of this, but I think it's what I'm going to go with. The side tubes are modeled with large launch lugs because Open Rocket can't do tube fins. I'm going to do them with BT-20 tubes that house streamers and they will be capped off with these nose cones from SEMROC:



What do you guys think?

[Wayco]

That will look really cool with those tubes on the sides, now if it will deploy streamers without altering the sustainers flight, that's another question.... Seems like I remember someone else on here did something like that, but I can't remember what the thread was called. Anyway, good luck with this build!

[Green Jello]

That will look really cool with those tubes on the sides, now if it will deploy streamers without altering the sustainers flight, that's another question.... Seems like I remember someone else on here did something like that, but I can't remember what the thread was called. Anyway, good luck with this build!

I learned about the technique from [POW]Eagle159 in this thread:

http://www.rocketryforum.com/showthr...-power-rockets