rcnitrohead

Hi all, me and SpikeX from the monster truck forums are teaming up to build a land missile Savage. At first, we wanted a turbine engine to propel the truck but we then saw that the fuel consumption was ridiculous as was the price. Now we have settled on a setup which is: We keep the engine mounted on the truck which gets us to 45mph. Our goal is to hit at least 60+ Now Ive seen some electric jets go 120+mph but I understand out goal is harder to reach since we must propel a 12 pound truck that is being slowed down from lack of aerodynamic construction and the friction of the wheels touching the ground. After the truck hits 45, the engine will still be spinning at full speed and thats where the fans come in. We are looking to have a 2-4 fan brushless setup. We need as much thrust as possible. We are complete noobs when it comes to electric flight so it relies on you guys to choose the best setup for us. As I said, the goal is to hit 60mph at least with a 12lb truck. We will be using two power sources (engines and the fans/motors), how can we hook that up so it all works? We want the engine to work independently on a separate channel than the fans/motors, how do we hook that up to an ESC? Ok so to summarize, we need 2-4 high power brushless fans, a decent ESC, and I dont know if we can use this but I'd prefer to use a LiPo car battery rated at 4000mah 11.1v. How much runtime can we expect with a setup like that? Remember, the fans will be working with the engine in the top speed run!Thanks a lot! Tom.

rcnitrohead

Guys what are the most powerfull setups while still being able to fit in the palm of your hand

mopartybob

FOUND THIS WHILE GOOGLING...http://www.bvmjets.com/ good stuff in here....

Flypaper 2

Tie twenty bicycle inner tubes together. Tie them to the front axle and start walking backwards till the rubber doesn't stretch any more. It will get you up to your 60 MPH and you don't even need a radio. Just make sure the tubes are well nailed into the ground or get ready to duck. On second thought, don't duck.

mopartybob

Hey dick,why do you want to reply to my post like that? these kids asked for some help with a legitimate question,and you want to flame them with a not so very objective reply,for every other super genius who has a reply like dick's,my opinion is don't be a dick,and don't reply....

rcnitrohead

No one have any suggestions? Oh and its probably cause hes canadian

rcnitrohead

Wow what a shame and these are the electric plane forums....

rcnitrohead

Guys do you think a fan like this with 20+oz of thrust would be enough? How many oz do you think I need in order to successfully propel my truck to high speeds? Thanks.

http://www.modelflight.com.au/rc_mod...c_midi_fan.htm

vicman

My Feedback: (10)

while not an expert in any of the requested fields of question. I am thinking you will end up with so much drag from the truck you would render the DF useless in efficiency. Also the batteries to get there are crazy expensive. (you mentioned that as a concern) If you really want to go fast with a land truck why not consider a RATO set-up for a short boost. You can do this much cheaper. I strongly advise caution and keep a fire extinquisher handy.

mopartybob

hey vicman thanks for the reply,we kicked that idea around also and it's been done to death....[:'(],Shoot,we even kicked around the idea of using a pulse jet set-up,there are some pretty outrageous edf units out there with enuff thrust to do what these guyz want,and what these guyz are looking for is somethin never been done before,so consider money is no object....[:-],what would it take for a 12lb.truck travelling at 45mph. to boost it up to 60mph.+......thanks

sharpshooter223

here is my honest opinion, keep in mind i am probably insane and kinda a pyro, but im not kidding when i say the following things. mix your own rocket fuel and stick them in steel tubes with the front end capped off. add an igniter that can be triggered by radio. i dont think a ducted fan would work either, not on the ground anyway, if you saw a ducted fan jet going 120+ mph i find it hard to believe that was an electric one, it was probably a glow engine. im not kidding about the home made rocket boosts though, just mount them on the back, there are many places you can find online that will give you recipes for the fuels. just be sure you arent driving it in any place with a fire hazard. but if you arent as crazy as me, i think your first idea of a real turbine would be the best way to go. the required stuff to get an edf POSSIBLY near enough to the power you need would cost almost as much, so why not use the real thing which im sure would give a ton more power. but as the last guy said, FIRE EXTINGUISHER!!!!

vicman

My Feedback: (10)

EDF is just not efficient enough at the moment to be used as a heavy pusher. If jing is not a prob go for the turbine. Find one on the bay and kick the tires and light the fires.
PJ is pretty noisy.
A cluster of D engines on the back is neat stuff.

mopartybob

thanks guyz,as for the rato idea...I was thinking more along the lines of G or N rated boosters..[:-]LOL

vicman

My Feedback: (10)

Obviously you will get plenty of thrust. Getting somone to release an engine to you is another matter. Hence my suggestion of a cluster. Just think how cool they look at dusk going down the street.

rcnitrohead

You guys dont think that something with this much thrust cant make us reach 60mph?? It seems like a lot, I made the caclulations and with a mediocre setup it comes out to 17 pounds of combined thrust. That definitely overcomes the weight of the truck, what do you think?[8D]

BTW weight of the truck with all the add ons should be 12lbs.

sharpshooter223

use rocket motors and you will reach way past 60mph. but with my earlier idea, if you were to learn to mix your own rocket fuel and fill steel tubes with it, then you could keep refilling and it would be cheaper. if you use a rocket engine, be sure you make a proper mount or it will melt the plastic of your truck very easily.

rcnitrohead

You dont think that the ducted fan idea would work?? I really dont want to use rockets if possible. Id rather use somthing reliable and clean that wont make my truck explode[&:]

sharpshooter223

well, then use an rc turbine, but there is no way electricity will work for it. rc turbine you can just use propane to warm them up then you switch over to kerosene, as i understand. this is really more a matter for the other plane forum cause thats where you will get the power you need. but using an edf would be like sticking a blow-dryer on the ground and turning it on full blast. theres alot of air being pushed, just not being pushed very hard. for that you need the rapid expansion of air from a rocket or turbine.

SpikeX

We thought of that too, but we realised is was much too expensive, complicated, and used way to much fuel.

Flypaper 2

How about a gas motor on the back set up like a swamp buggy. 40to 45 CC motor with a pusher prop around 18 in. dia. A reed valve motor would run backwards so you wouldn't need a pusher prop.