Subject:
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Re: rocket powered LEGO vehicle
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Newsgroups:
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lugnet.loc.ca.bc.vic
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Date:
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Wed, 24 Nov 1999 20:43:08 GMT
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Viewed:
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2386 times
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> As James said, a longer burn might best. The majority of the energy might
> be spent breaking the momentum of rest. In a several gram cardboard tube
> not as big problem, lego vehicle (LV)... substancial problem. One
> suggestion might be engaging the engine after the LV has started moving. I
> am thinking of some sort of incline that the LV would roll down (two of
> those Hot Wheel tracks maybe?) and the engine would be engaged once the LV
> hit the flat (moving). This could incorporate the MS in a neat way; sensing
> when the engine should be engaged rather than just engaing it... touch
> sensor tripped, light beam broken, excetera.
>
> The engery equivilant of, Randy lifting the LV to the top of an incline,
> might be _several_ engines, depending on the mass of the LV.
No, the engines have a fair amount of energy. I will have to go and dig up my
sheets on the engines...(goes away, comes back soon)
First off, some physics.
Ep=MGH
Ek=1/2 mv^2 (thats V squared)
Where,
Ep= Potential Energy (gravity)
Ek= Energy to get something to a speed (Energy Kinetic) Both in J
M=Mass (in kg)
G=9.8 (gravity)
H=Hight
V=Velocity
Now, taking a look at my handy ESTES catalog, the motor I am suggesting has a
rating of
C-5-3 Total Impulse=10 N/S
Delay 3 sec
Max Thrust 5 Lb
Thrust Duration 2.1 Sec
(average thrust is 4.76 N, appiled for 2.1 sec)
(this is a very peaked graph, if you look at it it is like v- upside down)
Now, if only I could find the conversion from N/S to J, then I could go and do
some calculations.
>
> As to the LV itself; four or three wheels might produce better initial
> reuslts.
Three, because then your friction is reduced.
> Doesn't the Extream Team have a rocket car? That might be a cool
> conversion. Other things I was thinking about... rear wheels behind thrust
> point; slight downward thrust rather that upward; I think that engines have
> a thrust value that could be used to calculate approximently, if you were
> looking at launching a ABS projectile capable of penatrateing steel, or just
> zipping across a parking lot :).
Yep. I don't think that we are in danger of breaking the speed of sound with
this one though...
James
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Message has 1 Reply:
Message is in Reply To:
 | | Re: rocket powered LEGO vehicle
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| Cool Idea Randy and Steve, Before I go on, I was thinking that we should be using The LUGNET *.loc group for this kind of stuff. I know that you posted this to RTL, but our little discussions within the group would be nice to be in the newsgroup (...) (25 years ago, 24-Nov-99, to lugnet.loc.ca.bc.vic)
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