ROCKET BOOSTED 1/8 SCALE RC CAR HELP

Discussion in 'The Watering Hole' started by arelee, Jan 11, 2020.

Help Support The Rocketry Forum by donating:

  1. Jan 12, 2020 #31

    jlabrasca

    jlabrasca

    jlabrasca

    Well-Known Member

    Joined:
    Oct 31, 2016
    Messages:
    1,414
    Likes Received:
    451
    Yes. And what the OP is proposing is not among them.

    Here, I think, is the OP's inspiration



    David Windestal is the knucklehead (and I use the term "respectfully") who launches (sugar) rocket-propelled knives at things.

    The OP is coming to this project after seeing somebody do a YouTube stunt; the entertainment value of which is that it is stupidly dangerous and poorly executed.

    The posts in this thread pretty much add up to the disclaimer that Windestal ought to have flashing along the bottom of his videos in a perpetual crawl: "DON'T TRY THIS!"

    The OP is getting the same kind of advice (expressed stridently or pleadingly) he'd get if he asked about building a mortar, or a manned rocket glider, or any other thing that falls this far outside the safety codes for rockets that go up.
     
  2. Jan 12, 2020 #32

    arelee

    arelee

    arelee

    Forum Supporter TRF Supporter

    Joined:
    Jan 8, 2020
    Messages:
    43
    Likes Received:
    0
    Gender:
    Male
    Location:
    Virginia
    If one speaks to the wind calmly and in measured tones, they would most likely walk away in a more tranquil state of mind.
     
  3. Jan 12, 2020 #33

    kuririn

    kuririn

    kuririn

    BARGeezer TRF Supporter

    Joined:
    Oct 3, 2016
    Messages:
    3,598
    Likes Received:
    1,175
    Gender:
    Male
    Location:
    Hawaii
    Since your RC car is not free-wheeling, when the rocket motor ignites the acceleration will be greater than the wheels can turn and it will tumble or become airborne.
    The ejection charge can be redirected out the back to vent or deploy a parachute.
    BSNW, a small correction. The Brits were the first to put jet engines in a car and go supersonic over a measured mile.
    The Americans were the first to put a jet engine in a car and set a land speed record.
    1964, Craig Breedlove and his team, Spirit of America Supersonic.
     
  4. Jan 12, 2020 #34

    arelee

    arelee

    arelee

    Forum Supporter TRF Supporter

    Joined:
    Jan 8, 2020
    Messages:
    43
    Likes Received:
    0
    Gender:
    Male
    Location:
    Virginia
    Thank you for your reply BSNW.

    All information from the folks on this forum is extremely valuable to me. I simply wish to discover how these motors function, the laws,and what safety measures I will need to take. Once I have, then I can confidently move onto the next step in the project.

    Have a nice day!
     
  5. Jan 12, 2020 #35

    arelee

    arelee

    arelee

    Forum Supporter TRF Supporter

    Joined:
    Jan 8, 2020
    Messages:
    43
    Likes Received:
    0
    Gender:
    Male
    Location:
    Virginia
    Thank's for the reply kuririn.

    Actually, the "GT" body that I will be placing on the car, created by "Delta Plastik", is aerodynamically built for speeds exceeding 160mph. They are working with me on this 'rocket boosted' project.

    When the car has reached its maximum speed, I will let off of the power and let the rocket take over. I have replaced the center differential gear with a "spool" gear. Basically making it free-wheeling at that point.

    Bye the way, should I refer to the rocket as a motor, or a charge?

    Thank you.
     
    Last edited: Jan 12, 2020
  6. Jan 12, 2020 #36

    kuririn

    kuririn

    kuririn

    BARGeezer TRF Supporter

    Joined:
    Oct 3, 2016
    Messages:
    3,598
    Likes Received:
    1,175
    Gender:
    Male
    Location:
    Hawaii
    The rocket engine is also called a motor.
    The ejection element or grain is called a charge.
     
  7. Jan 12, 2020 #37

    arelee

    arelee

    arelee

    Forum Supporter TRF Supporter

    Joined:
    Jan 8, 2020
    Messages:
    43
    Likes Received:
    0
    Gender:
    Male
    Location:
    Virginia
    Yes, Windestal was preforming, in my opinion, some pretty foolish stunts. Not my plan. His video simply sparked my curiosity in creating a car that would run straight and fast, with the inclusion of a rocket motor. However in his defense, in one of his other videos, he shows how he made his casing. He's no slouch in that department.
     
  8. Jan 12, 2020 #38

    boatgeek

    boatgeek

    boatgeek

    Well-Known Member

    Joined:
    Dec 27, 2014
    Messages:
    2,236
    Likes Received:
    675
    If you use Aerotech motors, you can leave out or remove the ejection charge. For reloads or LMS, just don’t put the ejection charge in. For other single use, you can pick out the red cap and dump out the powder.
     
    arelee likes this.
  9. Jan 12, 2020 #39

    arelee

    arelee

    arelee

    Forum Supporter TRF Supporter

    Joined:
    Jan 8, 2020
    Messages:
    43
    Likes Received:
    0
    Gender:
    Male
    Location:
    Virginia
    Thank's BSNW.

    For what it's worth,before I retired, I was in the medical field= cellular and molecular neurological surgery research, and cardiovascular research at Stanford, then University of Virginia.
     
  10. Jan 12, 2020 #40

    arelee

    arelee

    arelee

    Forum Supporter TRF Supporter

    Joined:
    Jan 8, 2020
    Messages:
    43
    Likes Received:
    0
    Gender:
    Male
    Location:
    Virginia
    Hey boatgeek,

    Actually, when I first started pondering this project, (not knowing anything about model rocket motors), I had my eye on an Aerotech G54W-14A White lightning. At this point, with advice from a member of this forum, It was suggested that I start with a smaller motor and work my way up. Made perfect sense.

    Thank's for the information. It has been noted.
     
  11. Jan 12, 2020 #41

    jlabrasca

    jlabrasca

    jlabrasca

    Well-Known Member

    Joined:
    Oct 31, 2016
    Messages:
    1,414
    Likes Received:
    451
  12. Jan 12, 2020 #42

    BSNW

    BSNW

    BSNW

    Well-Known Member

    Joined:
    Jan 2, 2017
    Messages:
    618
    Likes Received:
    225
    Very interesting! I work in lab that studies renal and cardiovascular disease. As you know...they are closely related. We also study the effects of the microcystin toxin on the liver.
    Anyway, have fun (safely) and I hope you accomplish your hobby goals! It's all good clean fun!
     
    arelee likes this.
  13. Jan 12, 2020 #43

    BSNW

    BSNW

    BSNW

    Well-Known Member

    Joined:
    Jan 2, 2017
    Messages:
    618
    Likes Received:
    225
  14. Jan 12, 2020 #44

    gldknght

    gldknght

    gldknght

    Well-Known Member

    Joined:
    Jan 26, 2011
    Messages:
    792
    Likes Received:
    99

    Yes, and a lot of people got seriously hurt or killed doing these 'dangerous' things. And now we have laws coming out of our whosis's limiting or outright preventing most of these same activities.

    To the OP,

    A midpower rocket motor assisted r/c car is a BAD IDEA!! Listen to the others here who have said the same thing!

    If you insist you want to try this, please start with this:
    https://estesrockets.com/product/002502-blurzz-rocket-powered-dragster-blue-storm/
    Gain some knowledge, gain some experience.
    Learn how these motors work, what they are capable of, and what makes them so dangerous if misused.
    Follow all safety requirements.

    Also, I don't know where you live, but in a lot of places, using any rocket motor for something it is not designed for, is illegal.
    Doing any rocketry related activity outside the laws will extremely quickly make you very unpopular here.
     
    Last edited: Jan 12, 2020
    arelee likes this.
  15. Jan 12, 2020 #45

    BSNW

    BSNW

    BSNW

    Well-Known Member

    Joined:
    Jan 2, 2017
    Messages:
    618
    Likes Received:
    225
    HEY!!!!! HEY!!! Who flew the G? Was that a G motor?
     
    solid_fuel likes this.
  16. Jan 13, 2020 #46

    Charles Botkin

    Charles Botkin

    Charles Botkin

    Member

    Joined:
    Jan 11, 2020
    Messages:
    8
    Likes Received:
    6
    We started with trying to use the ejection charge to deploy a rear facing chute in a tube connected to the engine tube through baffles to prevent burning the chute.
    On the first try with this we discovered the chute would instantly pop out as the car accelerated from 0 to whatever and drag/shred and burn the chute till the ejection charge fired.
    The next test was with the chute attached to a 2ft length of steel fishing leader with a swivel eyelet placed roughly 100ft down the guide wire. *Note the second test was with the early small cars and an Estes C class booster motor which has no ejection charge. This worked in theory and on paper, but with the real world tests we quickly discovered that the chute needed to be further down the wire and stowed between two weighted pieces of cardboard to keep any breeze from moving it.
    As we did more testing and the cars became larger and the motors also became larger we began using chute deployment more like a current high powered rocket with nylon chutes and an electric timer with powder charge, but we went back to a rear facing tube with duct tape over the end to keep the chute in place.
    We tried and gave up on cluster motors early on as it was just too hard to get simultaneous ignition and we could just use a larger single motor if we wanted more speed..
     
    arelee likes this.
  17. Jan 13, 2020 #47

    arelee

    arelee

    arelee

    Forum Supporter TRF Supporter

    Joined:
    Jan 8, 2020
    Messages:
    43
    Likes Received:
    0
    Gender:
    Male
    Location:
    Virginia
    Hi BSNE,

    As you know from your medical research experience, the only way to achieve the goal at hand, is to thoroughly study all aspects,
    to complete the given plan.

    Thank's, and have a great day!
     
  18. Jan 13, 2020 #48

    arelee

    arelee

    arelee

    Forum Supporter TRF Supporter

    Joined:
    Jan 8, 2020
    Messages:
    43
    Likes Received:
    0
    Gender:
    Male
    Location:
    Virginia
    Hello gldknght. Thank's for the input.

    When I started this project, not knowing anything about model rockets, I assumed that a "G" motor would be my best choice, since the car would already be traveling at a speed exceeding 120mph. I even wondered if a "G" motor would be able to increase the speed any further. That's why I joined this forum. To find out, from folks that know model rocket motors, if I was correct. If I was wrong, what would their choices be. Obviously, I was wrong. One member suggested starting with smaller motors and working my way up. Makes perfect sense.

    Going into a project like mine, needs to be researched thoroughly. Until I have all information, both technical and legal, this project will not proceed. Period! That's why I appreciate ALL input given to me.
     
  19. Jan 13, 2020 #49

    Marc_G

    Marc_G

    Marc_G

    Well-Known Member

    Joined:
    Jun 6, 2010
    Messages:
    5,995
    Likes Received:
    180
    Gender:
    Male
    Location:
    Indianapolis Metro Area
    This reminds me of the outrage on gun and drone forums when some idiots decided to create a drone that could carry and fire a firearm, in a homebrew lash-up experiment. Bad idea from the start.

    How much does the car weigh, prior to any needed modifications? I can't imagine even a G will give it that much of a boost.
     
  20. Jan 13, 2020 #50

    arelee

    arelee

    arelee

    Forum Supporter TRF Supporter

    Joined:
    Jan 8, 2020
    Messages:
    43
    Likes Received:
    0
    Gender:
    Male
    Location:
    Virginia
    Overall, it will weigh-in at around ten pounds. I don't remember if I mentioned this before, but "Delta Plastic" is working with me to decide on The best "GT" body, that would prove to have the most suitable aerodynamics for this project.

    About the G motor, as I mentioned, I was concerned about that. Not being certified, I can't go any bigger, (but you already know that).
     
    Last edited: Jan 14, 2020
  21. Jan 13, 2020 #51

    Marc_G

    Marc_G

    Marc_G

    Well-Known Member

    Joined:
    Jun 6, 2010
    Messages:
    5,995
    Likes Received:
    180
    Gender:
    Male
    Location:
    Indianapolis Metro Area
    For what it's worth, a G motor will usually have a maximum lifting weight around 3 pounds. Which means, under typical conditions, a G motor can (barely) lift a 3 pound rocket with enough initial acceleration to provide stability via airflow over the rocket by the time it leaves the rail. You'll need to look this up but I think for rockets of this size / configuration this may be something like 50 miles per hour as it leaves the rail, probably 2/10 of a second after the motor finishes chuffing, fighting against gravity. This probably gives you enough to figure out the initial acceleration such a motor provides for a 3 pound rocket.

    What you propose will be using about 3+ times more weight, but not fighting against gravity (just friction and wind resistance). Imagine you are at full car motor speed, then kill power to put it in freewheeling mode. How much of a G does friction/drag impose on the car as its power stops? Perhaps this information plus what has been posted above will help a back of the envelope calculation about what sort of speed boost you will see during the 1 second or so that it is at initial thrust, balancing the friction/drag instead of downward G the rocket would face.

    Others have/can talk more in detail about the G limitation versus certification, but in most places I'm familiar with, any use of the motors inconsistent with its labeling would be both illegal (not just against a hobby code, but actually against the law) and a specific violation of fire codes, depending on your state regs about that. Private property doesn't matter to these considerations. Should you proceed, I recommend having the Delta Plastic company provide a written contract specifying they will insure you for the replacement cost of any structures nearby (including contents) plus the value of any human lives nearby (given this is a damn fool stunt that a jury or judge would condemn, go with $5M per person within half a mile or so).
     
  22. Jan 14, 2020 #52

    David M Schigoda

    David M Schigoda

    David M Schigoda

    Active Member

    Joined:
    Aug 16, 2019
    Messages:
    27
    Likes Received:
    12
    Gender:
    Male
    Arelee,

    Have you taken a look at the Budweiser Rocket Car from 1979. It reportedly exceeded Mach 1. Here is a video that outlines the development of that (non- F.I.M.) manned rocket car.

    On their first run at Edwards Air Force Base, the car did 0 to 800 kph in under 10 seconds!

    Earlier, in 1970, the rocket car "The Blue Flame" also did quite well. It appears to be nearly the same design.

    If you were to use this type of "car design" for your model - you could save a lot of weight, complexity, aerodynamic drag and expense. This makes more sense to me than attempting to accellerate and control a bulky, heavy, complex, expensive RC car.

    Since it would be tough to control it - when accelerating from a standing start (since the electric r/c car motor wouldn't be a part of this of type design), you could maybe use a modified "Hi-Start" or catapult(?) to get it moving fast enough to obtain aerodynamic stabilty, before igniting the rocket motor. https://www.horizonhobby.com/hi-start-450-2-3m-efla650 [Hi-Starts are used to launch RC gliders].

    And remember - Don't try this at home. And you didn't hear this from me. ;o)
     
    arelee likes this.
  23. Jan 14, 2020 #53

    arelee

    arelee

    arelee

    Forum Supporter TRF Supporter

    Joined:
    Jan 8, 2020
    Messages:
    43
    Likes Received:
    0
    Gender:
    Male
    Location:
    Virginia
    Hello Marc_G

    "Delta Plastik" simply fabricate lexan bodies for RC cars. They are not sponsoring my project, simply making suggestions as to a body type.

    As I have mentioned above, ALL technical and legal parameters are being addressed. If any of these factors cannot be met, this project will end. It's that simple.
     
  24. Jan 14, 2020 #54

    arelee

    arelee

    arelee

    Forum Supporter TRF Supporter

    Joined:
    Jan 8, 2020
    Messages:
    43
    Likes Received:
    0
    Gender:
    Male
    Location:
    Virginia
    Hi David.

    Thank's for the videos and the suggestions. Very impressive!

    I am not going for a land record. You are correct, even with an aerodynamically designed body for my car, it will, in regard to speed, still be less effective than the above videos show. What I am trying to do, is find out how fast I can push a couple of my RC cars. I chose the "Typhon 6S BLX V4" as my first platform. If you look at my avatar photo, it is the in the car in front, (before any modifications were done). If, after experimenting with it, and it proves to be a success, then my next plan is to try it on my "Limitless", (the car on the left in the avatar photo).

    Have a great day!
     
  25. Jan 14, 2020 #55

    arelee

    arelee

    arelee

    Forum Supporter TRF Supporter

    Joined:
    Jan 8, 2020
    Messages:
    43
    Likes Received:
    0
    Gender:
    Male
    Location:
    Virginia
    Thank's for the detailed information. Very helpful and something to seriously consider.
     
  26. Jan 14, 2020 #56

    dr wogz

    dr wogz

    dr wogz

    Fly caster

    Joined:
    Feb 5, 2009
    Messages:
    5,101
    Likes Received:
    496
    Location:
    Land of Poutine!
    I don't understand why you want to add a rocket motor to t a car that's not really designed for "go fast" speeds.. Especially if you are on a hard / paved surface.

    Why not go with a proper 2-wheel drive car, one that's road ready: limited suspension, foam / grippy tires, tight steering controls, lighter & already "aerodynamic", low CG, smooth underbelly for added road-stick..
     
    arelee and David M Schigoda like this.
  27. Jan 14, 2020 #57

    blackjack2564

    blackjack2564

    blackjack2564

    Crazy Jim's Gone Banana's

    Joined:
    Jan 18, 2009
    Messages:
    8,906
    Likes Received:
    1,022
    Location:
    Savannah Ga
    As I mentioned ,test mule would be first thing to do. Once that passes muster incorporate proven aspect ito actual car ...BUT where ya going to mount the rocket motor? It needs to be as low as possible and centered.
    This blow up up your car doesn't show any room, do you have a work-around?

    Then the center of pressure issue must be addressed or the car will tumble forward or flip, when motor is engaged.
    http://www.formula1-dictionary.net/aerodynamic_balance.html

    I see the inherent speed design is 70mph+ is your souped up for the 120mph you mention? Does this extra speed get special tires/rims designed for that ,or the ones on it capable of handling the extra stress.
    Are the tires one piece or on rims, they must be able to handle centrifugal forces or they will expand and fly off the rims.
    Once motor is engaged it will propel car faster than electric motor [unless some free wheeling device is there?] this may also cause the car to flip forward due to electric motor lock up.
    There are some 24mm G motors [78lb thrust vs 20-30] that have 2x-3x more thrust than a 29 -g are slimmer and may be easier to mount.
    How much ground clearance between that center mounting and ground, that's where I would put a motor if possible. It would help great deal with keeping low and forward center of gravity.

    The motor I chose would kick it in the butt...78lbs of thrust in a 9lb car is 8.67 thrust to weight ratio . If I was going to all the trouble to do this..I would take it too the limit. It also is low voltage ignition further reducing mods to light it. Do you have an extra channel to route the firing through? this one can be piggy backed to your on board battery. no need for another.

    Screen Shot 2020-01-14 at 12.58.08 PM.png Screen Shot 2020-01-14 at 12.58.49 PM.png Screen Shot 2020-01-14 at 1.09.26 PM.png Screen Shot 2020-01-14 at 12.51.44 PM.png
     
    Last edited: Jan 14, 2020
    arelee and David M Schigoda like this.
  28. Jan 14, 2020 #58

    Walter Longburn

    Walter Longburn

    Walter Longburn

    Member

    Joined:
    Aug 27, 2018
    Messages:
    17
    Likes Received:
    4
    Location:
    Kansas
    How would he get a G145 without certification? If I was doing it I probably would use a DMS G80 or if I didn't want to pay hazmat I might use a LMS G79 or G78. Unless he wants to buy hardware...
     
  29. Jan 14, 2020 #59

    blackjack2564

    blackjack2564

    blackjack2564

    Crazy Jim's Gone Banana's

    Joined:
    Jan 18, 2009
    Messages:
    8,906
    Likes Received:
    1,022
    Location:
    Savannah Ga
    I said "if I was doing it". However if I were anywhere near the guy I would donate whatever needed rocket supplies to him and help install it.
    This is a fascinating project if you read his RC forum thread. Very do-able with some serious research.
     
    jd2cylman and Titan II like this.
  30. Jan 15, 2020 #60

    arelee

    arelee

    arelee

    Forum Supporter TRF Supporter

    Joined:
    Jan 8, 2020
    Messages:
    43
    Likes Received:
    0
    Gender:
    Male
    Location:
    Virginia
    Hi dr wogz,

    Actually, The Typhon 6S BLX V4 is a platform that many RC enthusiasts modify for speed. It's a fast car out of the box. If you check-out my thread on Arrma Forum="TYPHON 6S BLX V4 MAXIMUM SPEED UPGRADE HELP", you can see what others are doing with theirs. In regard to the "LIMITLESS", if you look at my avatar photo on this forum, the car on the left is a Limitless. That will be my next project, providing that the technical and legal aspects work out with the Typhon.
     

Share This Page

Group Builder