E E Express

Discussion in 'Scratch Built' started by Wayco, Aug 21, 2012.

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  1. Aug 21, 2012 #1

    Wayco

    Wayco

    Wayco

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    This summer I decided to support Marc G. and not buy any kits until I had used up some of the stuff I already have. This build fit right into that idea since I had a couple of BT-55 tubes and a left over 24mm MMT from an Executioner that I built with a 29mm MMT. The only thing I needed was a N/C to fit the body tube and some centering rings. Found both of those at Uncle Mikes Rocket shack, so I'm in business.
    Green Jello was asking about modifying his CC Express to use E motors, and when I took a look at mine I discovered that most of the fins on the booster had been cracked after just a few launches. I suggested he add recovery to compensate for the heavier E motors and I think he is working in that direction with his build here:
    http://www.rocketryforum.com/showth...s-CC-Express-Mod-Project&highlight=CC+Express
    My build went in another direction, I'm trying to beef up the booster so I don't crack fins every time it lands. I started by cutting my fins slightly longer and making them through the wall. I papered the fins and sealed the edges with medium CA. The MMT was modified with "stringers" that filled the gap between the body tube and MMT:
    [​IMG]

    That photo also includes the half moon baffles and bulkhead/anchor for the sustainer. I had a piece of blue tube that fit perfectly inside the BT-55 and that made cutting the slots much easier:

    [​IMG]
    I added a piece of masking tape to protect the blue tube, then managed to score it anyway. No biggie, it will buff out when I need it later.
    The tricky part was getting the body tube slots to line up with the stringers when gluing it together. I did pretty good with that and the slight mis-alignment was corrected with an exacto knife. Balsa wood is so easy to work with.
    [​IMG]

    I used Titebond in the slots, let it dry a bit and stuck the fins in with more glue on the root edge. My modified fin guide came in handy for this:
    [​IMG]

    The sustainer was done the same way with stringers and TTW attachment of the papered fins. I also added the baffle pieces using the blue tube to slide them in. I use Elmers glue-all for couplers and baffles, and treated the pieces with 5 min. epoxy to endure the ejection charge. My eye bolt is attached with a wire nut and washer that are epoxied in place. I use kevlar for recovery and the eye-bolts are brazed shut for added strength. Here it is ready for paint:
    [​IMG]

    I really like the N/C I got from Uncle Mikes, just not sure what it is made from. It's not blow molded so it doesn't have the seam, but it has a nice attachment point that runs the length of the cone:
    [​IMG]

    This build took me a bit longer than usual, mainly because I had to figure out the different sizes to fit the "E" motors. Then adding the stringers to the MMT was a little tedious. All in all, I'm quite pleased with the outcome. Now it just needs to survive the new E12 motors.....

     
    Last edited: Aug 2, 2013
  2. Aug 21, 2012 #2

    AfterBurners

    AfterBurners

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    Nice work...looks great so far. Can't wait to see the final rocket! Awesome!!
     
  3. Aug 21, 2012 #3

    El Cheapo

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    You're going to need a new set of bino's to track that thing.
     
  4. Aug 21, 2012 #4

    Wayco

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    Well, here it is with my original kit built CC Express:
    [​IMG]

    I stuffed a Top Flight 18" thin mill chute in it and weighed it, came out at 4.4 oz. The kit version with several coats of paint and decals on all the booster fins weighs 6.8 oz. I think I will reverse the colors on the sustainer and thanks to Green Jello, I will have another set of fin decals for the booster on this new rocket.
    I forgot to mention I double glued the fin fillets, using Titebond original first, then the "Trim and Molding" glue to finish. Should be a much stronger rocket than the kit rocket with all the added touches.
     
    Last edited: Aug 2, 2013
  5. Aug 21, 2012 #5

    Wayco

    Wayco

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    Yeah, you are probably right Tom. That is if it doesn't self destruct with the E12's in it. Maybe I should launch it first with D12's? NAH, E12-0/E12-8 and kiss it goodby! I have a spare after all....
     
  6. Aug 21, 2012 #6

    JPVegh

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    I'm gonna guess about 2900' on 2 Es. If you don't lose it you're definitely going for a long walk. Should be pretty cool man.
     
  7. Aug 21, 2012 #7

    Wayco

    Wayco

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    Green Jello posted these up on his thread:
    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'

    Long walks and chasing rockets is all part of my exercise program, so nothing new here. I have a Garmin forerunner that I use when I go to the launches. At the last big launch, I logged 9.21 miles running and walking! Launched at least ten rockets that day....
     
  8. Aug 22, 2012 #8

    JPVegh

    JPVegh

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    LOL! Well I never said that it wasn't an educated guess.:wink:

    Yeah, chasing rockets is the only real exercise I get these days, well that and walking back and forth to the laundry room. Maybe I should get a pedometer.
     
  9. Aug 22, 2012 #9

    Green Jello

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    Wow, I sure am mentioned a lot in this thread. That is looking great Wayco! I love the look of the motor / fin mount.

    As you mentioned I'm adding streamer recovery to the booster stage and I changed the fins to be 1/8" instead of 3/32".

    At the moment when I run the sim on Open Rocket, it's showing 3,249' on a E12-0, E9-8. I can't wait to get this one done and press the button. Weeeeeeee!
     
  10. Aug 22, 2012 #10

    dixontj93060

    dixontj93060

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    Nice project!
     
  11. Aug 23, 2012 #11

    Wayco

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    You're one of the reasons I started this build. The other being the questionable reliability of the new E12's.
    I cut my fins from 3/32" balsa, but after adding copy paper, they are very close to 1/8". I cut the fin slots 1/8", and they fit nice and snug.
    I'm flying mine in a couple of weeks at the SSS September launch. Unfortunately, I don't have an altimeter, so no way of knowing how high it will go. Would be interesting to know how real world performance compares to the sim's you ran. Does Open Rocket calculate Cd? I use Thrustcurve.com to estimate altitude and delay, and use .7 for the Cd on all my rockets. Be sure to take a picture of it when you finish it, I want to see how the pods came out. That might be the only record of this rocket we get before you launch it out of sight.....
     
  12. Aug 23, 2012 #12

    Rocketbuilder

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    This should be interesting! I'd say even if you had an altimeter, don't put it in that thing... You would probably never see it again.
    I LOVE that technique of putting the balsa spars on the motor mount tube; I'll definitely have to try that on my next build with TTW fins.
    +1 on skinning fins with the paper left over from cutting out Payloadbay templates! :D
     
  13. Aug 23, 2012 #13

    Green Jello

    Green Jello

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    I'm drilling the holes in the body tube tonight so it can give my JL Alt2 a ride. I will of course post the results.

    As for the pods....I'm starting to think I want a way to make them removable. Any ideas?
     
  14. Aug 23, 2012 #14

    Rocketbuilder

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    Glue little wood blocks inside the main BT where the pods are attached, and maybe smaller ones inside the pod, if possible. Then cut some small holes (and I know how good you are at cutting small holes in tubes ;)) in the outsides of the pods to allow screw driver access, and attach the pods with screws through the wood blocks. :2:
     
  15. Aug 23, 2012 #15

    Green Jello

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    Interesting idea. That might just work. Anyway...I'll move this question to my build thread so Wayco's doesn't get hijacked.
     
  16. Sep 5, 2012 #16

    Wayco

    Wayco

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    Just finished up my rocket, pretty happy with the outcome.

    [​IMG]
    Just finished loading it with an E12-0/E12-6 and prepped the recovery with some dog barf and an 18" thin mill top flight chute. If it survives it's first flight this Saturday, I will add the decals.
     
    Last edited: Aug 2, 2013
  17. Sep 5, 2012 #17

    Green Jello

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    Nice. What's the weight?
     
  18. Sep 5, 2012 #18

    Wayco

    Wayco

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    9.9 oz loaded with the E12's.
     
  19. Oct 5, 2012 #19

    Wayco

    Wayco

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    Finally got to launch this rocket a while ago and I must say it far exceeded my expectations! Video cut off before ejection, but it looked like a good 3000 ft. flight:
    http://s237.photobucket.com/albums/ff142/phx602biz/?action=view&current=MVI_0693.mp4
    Since it did so well on it's first flight, I added the decals:
    [​IMG]
    The through the wall fins mounted slightly forward on the booster survived it's first descent perfectly too.
     
  20. Oct 5, 2012 #20

    Green Jello

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    Nice flight. Really straight. I'm still waiting to launch mine on 2 Es.
     
  21. Oct 5, 2012 #21

    Rocketbuilder

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    Yup, looks like it went very well! And you even got it back! :surprised:
    You can see what some arcing over at what looks like the point of staging, and the upper stage seemed to have just a little bit of an S-curve to it, but I think you still got plenty of altitude! :D
     
  22. Oct 6, 2012 #22

    Wayco

    Wayco

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    The reason for that launch was my concern flying a scratch built rocket that wasn't like the kit version in a crowded environment. The next SSS club launch is our BIG GHS two day launch Oct. 27th and 28th. Lots of people just come out to watch, and with all the changes I did to the original design, I was worried that it might not go where it's supposed to go (UP). After watching it and your comments, I think the coupler between the booster and sustainer might be a little tight. Otherwise, it performed perfectly. Recovered it 100 yards from the launch, and the 18" chute brought it down softly. No worries flying it in a crowd now.
     

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