Quantcast
L2 Semroc Laser-X Upscale


Page 1 of 3 1 2 3 LastLast
Results 1 to 30 of 75
  1. #1
    Join Date
    17th August 2010
    Location
    Valley Center, Ks
    Posts
    275

    L2 Semroc Laser-X Upscale

    I am planning on building a scratch upscale of the Semroc Laser-X. I have attached the OR file. I am planning on Dual Deploy with an Adept22. My question at this point is the main deploy is happening at 84.3 ft/s. Is that too fast for a Top Flight Par-70 chute and 1" tubular nylon. The BT will be 4" PML Quantum tube. My goal is to have this completed for AirFest 18 Labor Day weekend for my cert. Probably on the AT J315 or J415. Eventually I will fly it on a K550 or K1275 and join the mile high club. Thanks in advance for your comments.
    Attached Files Attached Files
    Last edited by davdue; 20th June 2012 at 04:19 AM.
    Dave
    TRA 13362
    Level 1 with Scratchbuilt KC Chief @ LDRS 30
    Level 2 with Scratchbuilt Wildcat (Semroc Laser-X 3X upscale) @ AirFest 18


  2. #2
    Join Date
    20th August 2011
    Location
    Windsor, Connecticut
    Posts
    2,335
    I will be watching this! Good luck!

  3. #3
    Join Date
    25th January 2009
    Location
    Out of my mind, please leave a message!
    Posts
    632

    Question

    Quote Originally Posted by davdue View Post
    I am planning on building a scratch upscale of the Semroc Laser-X. I have attached the OR file. I am planning on Dual Deploy with a PerfectFlite Stratologger (may use Adept22 if funds are short). My question at this point is the main deploy is happening at 84.3 ft/s. Is that too fast for a Top Flight Par-70 chute and 1" tubular nylon. The BT will be 4" PML Quantum tube. My goal is to have this completed for KloudBurst 22 Labor Day weekend for my cert. Probably on the AT J315 or J415. Eventually I will fly it on a K550 or K1275 and join the mile high club. Thanks in advance for your comments.
    I don't have OR so I have questions 84.3 ft/s = 57.477 272 727 mph So how big is your drogue? How heavy is the rocket?
    If the parachute is packed correctly especially if it is in a deployment bag I don't see a problem.

    Bill Richardson ENC USNR Ret.
    TRA 8703 L3

    It is my opinion that stupidity should be painful, very painful. If it was I think there would be less of it in the world today.

  4. #4
    Join Date
    19th January 2009
    Location
    Stafford VA
    Posts
    3,440
    Sailorbill is asking the right questions. I don't use open rocket either, but how you set up your dd, how long the shock cords are, weight of the two halves, all play into what happens when the main deploys.

    If you have a long shock cord on the drogue side and the upper payload is heavy, it can go ballistic and drag the fincan behind it. When the main deploys, the fincan can fall into the main and take it out, or if it misses, the main will be almost stopped because only the weight of the upper section is on it until the fincan hits the end of the shock cord. Either way, bad things can happen.

    I would recommend a drogue shock cord about 2x the length of the full rocket with a drogue just big enough to keep the upper section above the fincan on the way down. Don't go much longer on your main shock cord either and ground test, ground test and ground test. Don't over do the charges. Having to lengthen the shock cords because of the charges means the charges are too big and leads to other problems with those long cords.
    Handeman

    TRA #09903 L2

    "If you don't use your head, you have to use your feet!" my Dad

    Tripoli Central Virginia #25 - BattlePark.org

  5. #5
    Join Date
    2nd September 2010
    Posts
    1,649
    Love the Lazer X. 14+ lbs seems heavy!
    NAR#91770 level 2
    TRA#13995 level 2

  6. #6
    Join Date
    17th August 2010
    Location
    Valley Center, Ks
    Posts
    275
    Quote Originally Posted by Sailorbill View Post
    I don't have OR so I have questions 84.3 ft/s = 57.477 272 727 mph So how big is your drogue? How heavy is the rocket?
    If the parachute is packed correctly especially if it is in a deployment bag I don't see a problem.
    The new OR has the ability to save as a RockSim file so it is attached.

    Drogue = 18" (not purchased yet so could be changed)
    Weight = 11.4 lb with AT J315

    I had no plans for a deployment bag but if it is necessary then I will do that. What is a normal acceptable drogue velocity? I have the main deploying at 800 ft but I could deploy higher to give more time to inflate if necessary. KloudBusters has a huge field just trying to minimize my walk! lol

    If you have a long shock cord on the drogue side and the upper payload is heavy, it can go ballistic and drag the fincan behind it. When the main deploys, the fincan can fall into the main and take it out, or if it misses, the main will be almost stopped because only the weight of the upper section is on it until the fincan hits the end of the shock cord. Either way, bad things can happen.

    I would recommend a drogue shock cord about 2x the length of the full rocket with a drogue just big enough to keep the upper section above the fincan on the way down. Don't go much longer on your main shock cord either and ground test, ground test and ground test. Don't over do the charges. Having to lengthen the shock cords because of the charges means the charges are too big and leads to other problems with those long cords.
    I was planning on asking about the shock cord lengths eventually. The payload section will be about 5 lbs. (weights from OR for NC, AV Bay, Transition, BT, Chute, Shock Cord)

    Love the Lazer X. 14+ lbs seems heavy!
    I found a RockSim file for the Semroc Laser-X and used it to scale the fins from today and with some other tweaking on the various hardware components it is now 11.4 lbs.
    Attached Files Attached Files
    Dave
    TRA 13362
    Level 1 with Scratchbuilt KC Chief @ LDRS 30
    Level 2 with Scratchbuilt Wildcat (Semroc Laser-X 3X upscale) @ AirFest 18


  7. #7
    Join Date
    17th August 2010
    Location
    Valley Center, Ks
    Posts
    275
    I have a 28" chute. I believe it is a LOC Precision. If I put that in for the drogue then my main deployment speed is down to 61.2 ft/s and OR doesn't give a warning anymore. It might drift a little further but shouldn't be too bad. I use that chute on my LOC IV and never have to walk to far to get it. Of course that is much lighter rocket than this one will be.
    Dave
    TRA 13362
    Level 1 with Scratchbuilt KC Chief @ LDRS 30
    Level 2 with Scratchbuilt Wildcat (Semroc Laser-X 3X upscale) @ AirFest 18


  8. #8
    Join Date
    17th August 2010
    Location
    Valley Center, Ks
    Posts
    275
    Another question on this build. Since the Laser-X has a boat tail with "fins" (see picture). I am planning on using either a flat plate or angles of some sort for an engine retainer. I can't really use the AeroPack retainer. But I do want to be able to fly this rocket on a 38mm motor. Are there any retainers that would work for this that I can buy? Are kind of adapter would work for this? Can I use the AeroTech without an AeroPack retainer. I will be using strictly AeroTech motors because that is the hardware I currently own.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	Laser-X.jpg 
Views:	74 
Size:	18.1 KB 
ID:	76702  
    Dave
    TRA 13362
    Level 1 with Scratchbuilt KC Chief @ LDRS 30
    Level 2 with Scratchbuilt Wildcat (Semroc Laser-X 3X upscale) @ AirFest 18


  9. #9
    Join Date
    20th August 2011
    Location
    Windsor, Connecticut
    Posts
    2,335
    The closest thing I can think of to use is an Aerpopac tailcone motor retainer. This would mean getting rid of the small fins on the end, but Then again, they do not serve much purpose. I think they would actually only make things more difficult with all of those fillets, which also adds weight...

  10. #10
    Join Date
    13th November 2009
    Location
    Katy, Near Houston (still Texas, though)
    Posts
    3,113
    Very cool!

    On the K motors, I would be a little squeamish about flying it unless there were a few layers of carbon on the fins. But that's just me.

    Greg

  11. #11
    Join Date
    17th August 2010
    Location
    Valley Center, Ks
    Posts
    275
    Quote Originally Posted by GregGleason View Post
    Very cool!

    On the K motors, I would be a little squeamish about flying it unless there were a few layers of carbon on the fins. But that's just me.

    Greg
    I may be totally off base here but one thing I have seen on TRF and other places it appears that a lot of folks over build their Level 2 rockets. Why would you be squeamish without CF on the fins? Even with a K550 I won't be approaching mach speeds. I believe OR tells me .74 mach. But I may be totally wrong and wish I had done some tip to tip. I had an engineering manager that once told me in God we trust all others bring data. I think this is a case where if some calculations were done we would find that for most rockets plywood with TTW attachment in a paper airframe would be plenty strong. Now with all of that said I don't have any data to support my opinion either. I am going to do some research in some of my old engineering text books and see if I can remember how to perform those calculations (I am an Electrical engineer not Mechanical) and see what I find.
    Last edited by davdue; 29th March 2012 at 05:56 PM.
    Dave
    TRA 13362
    Level 1 with Scratchbuilt KC Chief @ LDRS 30
    Level 2 with Scratchbuilt Wildcat (Semroc Laser-X 3X upscale) @ AirFest 18


  12. #12
    Join Date
    17th August 2010
    Location
    Valley Center, Ks
    Posts
    275
    Finally got my parts purchased and started working on it. I cut the aft fins out of 1/4" Baltic Birch plywood today. I tried making my own centering rings with a circle cutter in my drill press but the motor tube was off center. I will go to my local dealer. Next week and buy them. I have one question though. Should I round off the leading edge of the fins? What about the trailing edges?

    I have done a lot of work on my OR file but I am typing this on my iPhone so I will upload it later.

    Thanks
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	image-3448068647.jpg 
Views:	71 
Size:	29.5 KB 
ID:	77931   Click image for larger version. 

Name:	image-370014079.jpg 
Views:	57 
Size:	60.7 KB 
ID:	77932  
    Last edited by davdue; 15th June 2012 at 04:24 AM.
    Dave
    TRA 13362
    Level 1 with Scratchbuilt KC Chief @ LDRS 30
    Level 2 with Scratchbuilt Wildcat (Semroc Laser-X 3X upscale) @ AirFest 18


  13. #13
    Join Date
    18th January 2009
    Location
    SW Michigan
    Posts
    2,223
    Ohhh this one looks interesting.

    *subscribe*

    Dave Brunsting | NAR 85879 | TRA 12369
    L1 - 11/04/07, Three Oaks, MI | L2 - 7/25/09, Muskegon, MI
    Michiana Rocketry
    Into The World of Dave

  14. #14
    Join Date
    13th November 2009
    Location
    Katy, Near Houston (still Texas, though)
    Posts
    3,113
    Quote Originally Posted by davdue View Post
    I may be totally off base here but one thing I have seen on TRF and other places it appears that a lot of folks over build their Level 2 rockets. Why would you be squeamish without CF on the fins? Even with a K550 I won't be approaching mach speeds. I believe OR tells me .74 mach. But I may be totally wrong and wish I had done some tip to tip. I had an engineering manager that once told me in God we trust all others bring data. I think this is a case where if some calculations were done we would find that for most rockets plywood with TTW attachment in a paper airframe would be plenty strong. Now with all of that said I don't have any data to support my opinion either. I am going to do some research in some of my old engineering text books and see if I can remember how to perform those calculations (I am an Electrical engineer not Mechanical) and see what I find.
    Totally understand the overbuild. I would say that for most fins plans, layups are not needed. However, my "gut" feel (I'm not an engineer) is that there is a stress intersection where the strake meets the part of the fin that kicks out. I'm visualizing that the fin may be susceptible to lots of torque when it gets to higher velocities. But, I haven't slept at a Holiday Inn Express and could be way off the mark!

    Regardless, it should be a great build and look forward to seeing the progress.

    Greg

  15. #15
    Join Date
    17th August 2010
    Location
    Valley Center, Ks
    Posts
    275
    Quote Originally Posted by davdue View Post
    I have one question though. Should I round off the leading edge of the fins? What about the trailing edges?
    Any suggestions?

    Thanks,
    Dave
    TRA 13362
    Level 1 with Scratchbuilt KC Chief @ LDRS 30
    Level 2 with Scratchbuilt Wildcat (Semroc Laser-X 3X upscale) @ AirFest 18


  16. #16
    Join Date
    13th November 2009
    Location
    Katy, Near Houston (still Texas, though)
    Posts
    3,113
    Quote Originally Posted by davdue View Post
    Any suggestions?

    Thanks,
    One idea would be to glue 1/4" birch rods to the leading/trailing edges. That will help to keep laminar air flow over the fins.

    http://www.mcmaster.com/#wood-dowel-rods/=h1ed5g

    Greg

  17. #17
    Join Date
    17th August 2010
    Location
    Valley Center, Ks
    Posts
    275
    I promised a new OR file the other day so here it is. I bought an Adept22 altimeter to use for DD on this. Ordered it Friday evening and received it yesterday. Awesome service. I am thinking of flying this rocket on an I motor at Sweaty Balls (Assuming I get it finished) in July to practice DD before I cert at AirFest.
    Attached Files Attached Files
    Dave
    TRA 13362
    Level 1 with Scratchbuilt KC Chief @ LDRS 30
    Level 2 with Scratchbuilt Wildcat (Semroc Laser-X 3X upscale) @ AirFest 18


  18. #18
    Join Date
    17th August 2010
    Location
    Valley Center, Ks
    Posts
    275
    Well I finally had some time to work on my rocket after re-painting my wife's 71 Mustang drag car. See picture below. I also spent some time building a BT slotting jig. It clamps the tube so i can use my router. The jig worked real good on the first two slots. After that the QT was hard to get clamped hard enough so it wouldn't move when I used the router to cut the slots. In fact the tube did move on the 4th slot so I will have some filling to do when I do the fillets.

    The Laser-X has fins just forward of the transition. Should I make 1/16" tabs and slot the payload tube or just surface mount the fins?

    This is my first build thread so I hope I can do a good job of presenting this build. I have learned so much reading everyone's build threads. Thank you for all of them.

    Sent from my iPhone using Forum Runner
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	image-436273443.jpg 
Views:	67 
Size:	47.9 KB 
ID:	86824   Click image for larger version. 

Name:	image-723609283.jpg 
Views:	62 
Size:	52.8 KB 
ID:	86825   Click image for larger version. 

Name:	image-3249799262.jpg 
Views:	69 
Size:	43.9 KB 
ID:	86826   Click image for larger version. 

Name:	image-898811006.jpg 
Views:	85 
Size:	231.9 KB 
ID:	86827  
    Dave
    TRA 13362
    Level 1 with Scratchbuilt KC Chief @ LDRS 30
    Level 2 with Scratchbuilt Wildcat (Semroc Laser-X 3X upscale) @ AirFest 18


  19. #19
    troj's Avatar
    troj is offline Wielder Of the Skillet Of Harsh Discipline, Potentate of Perilous Pans TRF_ADMIN.png
    Join Date
    19th January 2009
    Location
    In a house
    Posts
    13,172
    For motor retention, if you want to keep the aesthetic, use a Slimeline retainer from Giant Leap. You can notch the vanes at the bottom so that they sit on top of the retainer. Done that way, someone would have to look really close to see that it's even there.

    -Kevin

  20. #20
    Join Date
    19th January 2009
    Location
    Hole in the wall near Savannah, GA
    Posts
    4,115
    Or even an Aeropac tailcone retainer would look cool The Laser-X is an awesome design, looking forward to progress reports!
    Chute Happens!!
    NAR 86940 L2
    TRA 12270 L3 09-01-12
    KF4GUL
    TeleTubby Fan, Unofficial King of Namby-Pamby Land

  21. #21
    Join Date
    17th August 2010
    Location
    Valley Center, Ks
    Posts
    275
    Quote Originally Posted by troj View Post
    For motor retention, if you want to keep the aesthetic, use a Slimeline retainer from Giant Leap. You can notch the vanes at the bottom so that they sit on top of the retainer. Done that way, someone would have to look really close to see that it's even there.

    -Kevin
    Were you thinking of the classic or the Qwik-Lok? I had been thinking of using their motorholder and using longer screws and spacers that would go between the vanes at the bottom.
    Dave
    TRA 13362
    Level 1 with Scratchbuilt KC Chief @ LDRS 30
    Level 2 with Scratchbuilt Wildcat (Semroc Laser-X 3X upscale) @ AirFest 18


  22. #22
    troj's Avatar
    troj is offline Wielder Of the Skillet Of Harsh Discipline, Potentate of Perilous Pans TRF_ADMIN.png
    Join Date
    19th January 2009
    Location
    In a house
    Posts
    13,172
    Quote Originally Posted by davdue View Post
    Were you thinking of the classic or the Qwik-Lok? I had been thinking of using their motorholder and using longer screws and spacers that would go between the vanes at the bottom.
    Personally, I'd go with the Qwik-Lok -- no tools required, which means no tool to get lost in your box at the time you need it.

    For a design like this, the Motor Holder would work, but it's going to affect the aesthetics quite a bit. Plus, you have to make sure the screws aren't able to shift and allow the clips to come off the motor, which I think is a greater risk as the exposed portion of the screws gets longer.

    -Kevin

  23. #23
    Join Date
    20th August 2011
    Location
    Windsor, Connecticut
    Posts
    2,335
    Quote Originally Posted by MasonH View Post
    The closest thing I can think of to use is an Aerpopac tailcone motor retainer. This would mean getting rid of the small fins on the end, but Then again, they do not serve much purpose. I think they would actually only make things more difficult with all of those fillets, which also adds weight...
    Really guys?

  24. #24
    Join Date
    17th August 2010
    Location
    Valley Center, Ks
    Posts
    275
    Due to Vacation Bible School family night I didn't have any time or energy to work on it last night. But, I did order the following from Top Flight Recovery: 1 ea PAR-70 (main), 1 ea PAR-24 (drogue), 2 ea 9/16" X 25' shock cords, 2 ea 300 lb swivels, 1 ea 12" X 12" Chute protector, 1 ea 9" X 9" Chute protector.

    I still need to get rail buttons, altimeter power switch, 54-38 motor adapter, and some other misc. stuff.

    Some questions first:

    1. I plan on using shear pins for the nose cone (plastic PML 3"). Where do you get those? Local hardware store? Seems like I have seen on here that people use nylon screws. What size (Apogee has 2-56 x 1/4") and how many?
    2. Should I use plastic rivets to hold the payload bay to the transition?
    3. I plan on using a 9V Alkaline battery for the Adept22 with Quest Q2G2 igniters. Is that ok or do I need a LiPo or something. Adept documentation says 9V alkaline is fine.

    Thanks,
    Last edited by davdue; 15th June 2012 at 06:30 PM.
    Dave
    TRA 13362
    Level 1 with Scratchbuilt KC Chief @ LDRS 30
    Level 2 with Scratchbuilt Wildcat (Semroc Laser-X 3X upscale) @ AirFest 18


  25. #25
    troj's Avatar
    troj is offline Wielder Of the Skillet Of Harsh Discipline, Potentate of Perilous Pans TRF_ADMIN.png
    Join Date
    19th January 2009
    Location
    In a house
    Posts
    13,172
    Quote Originally Posted by davdue View Post
    1. I plan on using shear pins for the nose cone (plastic PML 3"). Where do you get those? Local hardware store? Seems like I have seen on here that people use nylon screws. What size (Apogee has 2-56 x 1/4") and how many?
    Your local hardware store, for 3", #2 nylon screws should work fine. You'll want to reinforce the plastic where you put in the holes -- a simple brass sleeve in the hole works fine for this. For a 3" airframe, I'd probably use 2.

    2. Should I use plastic rivets to hold the payload bay to the transition?
    That'll work fine.

    3. I plan on using a 9V Alkaline battery for the Adept22 with Quest Q2G2 igniters. Is that ok or do I need a LiPo or something. Adept documentation says 9V alkaline is fine.
    Duracell 9V, and you should be fine, but ground test, first.

    -Kevin

  26. #26
    Join Date
    17th August 2010
    Location
    Valley Center, Ks
    Posts
    275
    Duracell 9V, and you should be fine, but ground test, first.
    Definitely ground test.
    Dave
    TRA 13362
    Level 1 with Scratchbuilt KC Chief @ LDRS 30
    Level 2 with Scratchbuilt Wildcat (Semroc Laser-X 3X upscale) @ AirFest 18


  27. #27
    Join Date
    17th August 2010
    Location
    Valley Center, Ks
    Posts
    275
    I rounded the fins, sanded the centering rings to fit, and cut the 54mm MMT to length. Here is the dry fit if the fin can and the payload bay on top (it is a little long since to make it a true scale it will be shorter). Later today or tomorrow I will start gluing the motor mount and fun assembly together. That is my daughter who loves Rockets almost as much as me. She has built an Estes Big Bertha and an Aerotech Initiator.

    Sent from my iPhone using Forum Runner
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	image-2344424243.jpg 
Views:	67 
Size:	51.4 KB 
ID:	87045   Click image for larger version. 

Name:	image-2757294191.jpg 
Views:	110 
Size:	50.4 KB 
ID:	87046  
    Dave
    TRA 13362
    Level 1 with Scratchbuilt KC Chief @ LDRS 30
    Level 2 with Scratchbuilt Wildcat (Semroc Laser-X 3X upscale) @ AirFest 18


  28. #28
    Join Date
    26th January 2010
    Location
    Northern California
    Posts
    10,435
    It's looking good! Is that an old Dodge truck in the background?
    NAR 91107, Level 2

    Help me, I'm drowning in rockets!

  29. #29
    Join Date
    17th August 2010
    Location
    Valley Center, Ks
    Posts
    275
    That is my son's 1977 Ford F100

    Sent from my iPhone using Forum Runner
    Dave
    TRA 13362
    Level 1 with Scratchbuilt KC Chief @ LDRS 30
    Level 2 with Scratchbuilt Wildcat (Semroc Laser-X 3X upscale) @ AirFest 18


  30. #30
    Join Date
    26th January 2010
    Location
    Northern California
    Posts
    10,435
    Quote Originally Posted by davdue View Post
    That is my son's 1977 Ford F100
    Oh well, I was close. LOL
    NAR 91107, Level 2

    Help me, I'm drowning in rockets!

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •