Turbine car update [Archive] - Radio Control Zone

EddieWeeks

08-18-2004, 12:01 PM

Another problem is I want to be able to have the car sitting there with
the turbine running at idle. Even at idle it still turns 35,000 rpms and
moves a lot of air... With my hosed up design that air will just go around
the turbo, but if I forced all that air into a turbo with a housing it will
most likely back pressure the turbine and overheat it..

My plan is to run it like this... cool and safe... then install a adjustable
plate just behind the turbine to deflect the hot air down..
This will force more of it to the bottom half of the turbo... if I force to much
it may run hot... The key is to make it adjustable..

Eddie

Hz-R

08-19-2004, 03:49 AM

Ah, didn't think of that, you've obviously thought this out more then I have! ;-)
With a turbo housing you would then some sort of valve as well, which would add even more weight..
It's pretty much all pioneering work you're doing there anyways, trial and error.. If you get it to work, this thing will surely scream!

Good luck!

Robbert

k_sw31

08-19-2004, 05:47 PM

Eddie-

I dont have a total understanding of how it will work but basically the exhaust from the turbine with spin that paddle type gear correct?

Wouldnt there be a potential danger in melting the body or any other plastic parts on the car? I believe those exhaust gasses will be above 500* C?

What about intake? Wouldnt the turbine need to be directly exposed to the air, not just sucking it out from inside the body?

Or is that where this turbo you keep talking about comes in to play?

Looks awesome!

EddieWeeks

08-19-2004, 06:21 PM

Every thing that goes in the car is in the pics.. It runs more like 600 C,
that is why the box houseing is all Stainless steel. I am just going to cut
a large hole in the back of the car body to let the exhaust out and a few
smaller ones for the intakes...

If it the box housing heats up the car too much. I will install some Stainless Steel
foil around that housing. I may even attach a small fan to one the drive shafts
to make it self cooling...

I think it will be fine... I have installed turbines in all foam airplanes before.. no problem

Eddie
http://www.corpcomp.com/weeks1/car/car.html

NotWalkinBlind

08-20-2004, 11:09 AM

Eddie, I know you iz lookin' forward to finishin' up and turnin' dat sumbeach loose.
:D :eek: :D

Piggy89373

08-20-2004, 11:46 AM

I bet that thing is going sound awesome...just the freakish high speed whine of the turbine. Man, when you get it finished and do a test run on video, don't add any music to the video.

EddieWeeks

08-20-2004, 01:46 PM

I have been doing some checking and only with minor assumptions
I calculated the power to the wheels to be around 8,000 watts..

An electric car would have to draw 330 amps with
20 cells to get this kind of power.

But then again, you never know whats going to happen... It
may just burst into flames... hahah

Eddie

NotWalkinBlind

08-20-2004, 02:51 PM

If it does, we wanna see that, too.

But have two versions of it... one with just the sound and one with music.

Now we need suggestions on the music... my first impression of something suitable would be... uh... "Whole Lotta Love"?

Piggy89373

08-20-2004, 03:03 PM

Guess that's better than "I don't want her, you can have her, she's too fat for me".

Actually, I was thinking more along the lines of Disturbed, "Sickness"

NotWalkinBlind

08-20-2004, 03:56 PM

Yeah... cool with that... or any other band that Zep paved the way for.

More suggestions, peeps... let your imagination run wild on a Friday.

nitrosportrules

08-21-2004, 12:25 AM

go with drowning pool, bodies and time it so when you hit the gas the song gets good(if you know what i mean, and if you listen to the song you will)

CENthasizer

08-21-2004, 12:31 AM

when do you think you will have a vid of your test run up eddie?

Toyotatogo

08-21-2004, 03:42 AM

It may just burst into flames... hahah

:eek: .........

promodvette

08-21-2004, 04:01 AM

Yo eddy I aint been around much lately buis keepin me away..but man you got a sweet idea on hand...Im thinkin...wastegate...have the turbine and a titanium tube with a servo that will work sorta like a nitro carb...let just enough air through but not enough for it to move...hit the throttle and open the gate and boom all the air from the turbine rushes through sendin that sucker 175 mph...LOL...Im gonna draw up what im talkin about tomorrow mornin and let you see what im really talkin about...i love the idea and the skills you are showin...thats awsome!

mtrsprt

08-21-2004, 01:28 PM

Eddie, just some constructive criticizm.

The design of air thrust to mechaincal energy, is going to lose about 70% of the efficiency of energy during the transfer. Im sure, you know this.

Isn't this type of design also going to need hundreds and hundreds of feet, to accelerate?????

Cory

EddieWeeks

08-21-2004, 06:03 PM

I don't disagree that it may be 30% efficient, but I was wonder
how you came up with that number..

Eddie

mtrsprt

08-21-2004, 06:12 PM

It was mostly an educated guess, but transfering kinetic energy to mechanical energy is a huge loss.

Anyway, I wish I had a turbine to play with!!!!!!!

Your tunnel that your thurst is going through, might want to be just barely slightly larger than your turbine gear fins, to make sure you can capture as much thrust as you can into the vanes.

NotWalkinBlind

08-26-2004, 05:51 PM

Eddie, yer bein' too quiet... what's going on?

How 'bout if we all go outside tonight at 9 P.M. Eastern time, and you rev it up a coupla times so we can hear what it sounds like?
:eek: :D :eek: :D :eek:

EddieWeeks

08-26-2004, 09:15 PM

I'll take some new pics tonight..

Eddie

EddieWeeks

08-27-2004, 12:46 AM

New pics and a small video

http://www.corpcomp.com/weeks1/car/car.html

Mike Keeney

08-27-2004, 01:38 AM

Nice vid Eddie, but I'd sure hate to see your bandwidth bill at the end of the month.

A couple of questions/comments/observations.

Why are you using a fan with blades that are curved on the end? It seems to me that you are losing surface area that could used for force. I would think that the best thing you could do would be to minimize the space between the blades and the tunnel to only a couple thou. at most. You'll never achieve 100% power transmission, but I think the open/missing blade area is allowing for a considerable power loss.

If you vector the exhaust straight out the back of the car I think you would probably still be ok with the rules since the majority of the power from the engine would have been directed and "used" by the turbine, I don't think the exhaust would contribute much forward momentum. It might be helpful in reducing the aerodynamic drag at the back of the car though. That might be a bit over the line so to speak.

Cheers,
Mike Keeney

NotWalkinBlind

08-27-2004, 10:50 AM

Eddie, is your present plan to run the exhaust straight out the back? You may have already said, but I don't remember.

Piggy89373

08-27-2004, 12:04 PM

After watching the vid, repeatedly, that has to be one of the loudest designs ever. Just the sound of airflow over the fins will be tremendous, I can only imagine adding the turbine noise into that. If nothing else, you'll definitely take first for scariest sounding entry.

In all seriousness though, have you tested the engine pushing the drivetrain yet?

EddieWeeks

08-27-2004, 02:24 PM

No.. All the jet thrust is going strait up.. I don't want any chance of
being disqualified... I will try to get the turbine running this weekend.

Peggy: Loud is an under statement. Even these little engines shake
your chest bone at full power.. But flying a jet powered airplane they
can be very quite (at 1/8 mile) away.

Mike: The reason I am using a curved bladed second stage turbine is because
I did not want to machine my own. That turbo charger turbo cost nothing
and is designed to turn > 80,000 rpm.. To make a tight fitting inconel paddle
wheel would take a lot of machine time. Also.. The car must stop at idle..
A tight fitting paddle wheel that was not spinning may back pressure the turbine
at idle.. All those gaps are there for a reason... As soon as I run this thing
and check the EGT (exhaust gas temp).. I may be able to add ramps to tighten
things up inside..

Eddie

Speedtester

08-28-2004, 01:15 AM

Eddie, If you have the thrust coming out the top wont the 16-18lbs of thrust cause the suspension to compress and make the car bottom out? Maybe you could make some kind of super wide dual side exhaust?

NotWalkinBlind

08-28-2004, 02:04 AM

How about an exhaust that goes straight out the back, but splits into a Y that flares out to point perpindicularly to each side. The only problem I can think of is you'd have to be certain that the gases are split exactly 50/50 throughout the entire RPM range so the side thrust wouldn't be uneven.

OK, so I guess that would be just about impossible to do... the perfect 50/50 thing.

I can't believe I used the word perpindiculary. Yukyukyukyukyuk.

Mike Keeney

08-28-2004, 02:43 AM

Mike: The reason I am using a curved bladed second stage turbine is because
I did not want to machine my own. That turbo charger turbo cost nothing
and is designed to turn > 80,000 rpm.. To make a tight fitting inconel paddle
wheel would take a lot of machine time. Also.. The car must stop at idle..
A tight fitting paddle wheel that was not spinning may back pressure the turbine
at idle.. All those gaps are there for a reason... As soon as I run this thing
and check the EGT (exhaust gas temp).. I may be able to add ramps to tighten
things up inside..

Eddie
Well that makes sense. I can see where back pressure could be a problem. What about a dump gate?

Do you think temprature will become a problem with the open gears? I would think rpm's that high would create a lot of friction.

I've got an optical RPM meter. I'll let ya borrow it if you want.

Cheers,
Mike

NotWalkinBlind

08-28-2004, 09:51 AM

Eddie, I just thought of something else for consideration in the exhaust vectoring... you've probably thought of all these, but... in case you haven't...

I'm sure you've seen those caps on race car exhausts... I have never known what they're for, but I think they're about 1/4" from the end of the pipe. If you ran your exhaust straight back, but had a flat plate positioned about 1/4" back, that would prevent any of the exhaust from being converted to thrust.

Of course, when you consider scale, that's a lot larger than on the real cars, but if it were closer, it might be too much back pressure.

NotWalkinBlind

08-28-2004, 10:03 AM

Found one on a motorcycle site... this one is adjustable... I realized I've seen them on crotch rockets, too.

http://www.cyclewareables.com/pages/exhausts_whitebrothers/whitebros_street_exhausts.htm

DanteXIII

08-29-2004, 12:24 AM

I don't want to be a jerk and post a super long reply, but i think i can help you out a little so if you want you can e-mail me at JJC_Neo@hotmail.com I don't know a great deal about the turbines your using but i know alot that i think could help you out.

P.S. I wouldn't worry about the suspension because the thrust coming out the top will be greatly decreased, a set of stiff springs should take care of it, and at the speed it'll be going the extra downforce will be neccisary. One little miniscule bump and it'll fly, literally, if you have next to no downforce that is.

Speedtester

08-29-2004, 01:13 PM

I stilll think exhaust coming out of the top is a very bad idea. Even if the exhaust is decreased on its way out it is still going to add alot of downforce which will put uneeded pressure on the suspension. I also think this could ruin the aerodynamics of the body design due to the air traveling over the top of the car and clashing with the exhaust air. The exhaust air will probally cause an airshield and prevent the needed air from traveling over the rear of the car like the body is designed to do. I guess we wont 100% know till Ed get his car out for testing but the other guys who posted have some great ideas also. I'm not sure if you live near any colleges but a few of the colleges around here have small wind tunnel cambers for their mini nascar gocarts. Perhaps you could ask them if they could help you with some testing or you donated a small donation to the school?

BTW: The Car looks awesome and I wish the best of luck with the testing and design.

I don't want to be a jerk and post a super long reply, but i think i can help you out a little so if you want you can e-mail me at JJC_Neo@hotmail.com I don't know a great deal about the turbines your using but i know alot that i think could help you out.

P.S. I wouldn't worry about the suspension because the thrust coming out the top will be greatly decreased, a set of stiff springs should take care of it, and at the speed it'll be going the extra downforce will be neccisary. One little miniscule bump and it'll fly, literally, if you have next to no downforce that is.

Mike Keeney

08-29-2004, 02:03 PM

I stilll think exhaust coming out of the top is a very bad idea. Even if the exhaust is decreased on its way out it is still going to add alot of downforce which will put uneeded pressure on the suspension. I also think this could ruin the aerodynamics of the body design due to the air traveling over the top of the car and clashing with the exhaust air. The exhaust air will probally cause an airshield and prevent the needed air from traveling over the rear of the car like the body is designed to do. I guess we wont 100% know till Ed get his car out for testing but the other guys who posted have some great ideas also. I'm not sure if you live near any colleges but a few of the colleges around here have small wind tunnel cambers for their mini nascar gocarts. Perhaps you could ask them if they could help you with some testing or you donated a small donation to the school?

BTW: The Car looks awesome and I wish the best of luck with the testing and design.
Go to any of those colleges and ask the aerodynamics professor if a bumble bee can fly. He will give you a very qualified and absolute "NO". But we all know it does. With enough power anything can move. In this case, Eddie's turbine will overpower any aerodynamic drag created by the exhaust. Personally, I think keeping the car on the ground at speed will be a major problem for all of us. Eddie's idea seems sound to me.

Cheers,
Mike

FastR

09-08-2004, 07:57 AM

Eddie,
NICE WORK!!

Can't wait to see that thing run! Good luck.

EddieWeeks

09-08-2004, 09:24 AM

http://www.corpcomp.com/weeks1/paddlewheel.jpg

p.n.e

09-11-2004, 07:41 PM

hey eddie, have you considered using presurized gas canisters instead of a turbine? I'm talking about stuff like paintball co2 canisters or something. Do you think they could put out enough pressure to get a car going? In which case you could get an industrial type canister and maybe get up to 3000psi in it?

Chris LaPanse

09-11-2004, 09:19 PM

Except that might count as a "Sacrificial" motor (I E not allowed) Also, they would not give you much run time at all, and they would be VERY heavy.

studysession

09-12-2004, 06:59 PM

Even if the sacrificial motor was allowed - what if it gave out to early. Just a thought.

Good work Eddie - A friend of mine is convinced that a jet engine is the way to go. If I had the budget, I would give it a try.

p.n.e

09-12-2004, 11:42 PM

well it was just a shot, but if it worked long enough i wonder would it be counted as a sacrificial motor? wouldnt the fan or turbo be the actual motor and the compressed air is the fuel? seems like a touchy issue since a nitro engine is also a sacrificial motor if you arent allowed to refuel!

Nightz

09-13-2004, 12:12 AM

Eddie, just wondering that if you assume the whole setup is probably ~30% efficient, wouldn't it be better to custom lengthen the turbine shaft to exit out the rear and be a turbine shaft into axle hybrid to reduce efficiency loss? And as for idling, the end of this CVD shaft can be the clutch setup.

EddieWeeks

09-13-2004, 11:04 AM

Nightz... That is not possiable.. That shaft turns 120,000 rpms and the only
reason it works at all is because its made of tool steel, harden then ground
and balanced... And evey now and then they still viberate..

I worked on the lathe some this weekend and cut the blank for the paddle wheel
as shown above.. Its made of 316L SS and took a while to cut from a 2.6" rod.
The most I could cut was 0.040 " per pass and then the chips would fly around
and burn any thing they touched.. I sould get the mill work done in a week or two.

Eddie

RrR

09-13-2004, 02:15 PM

Why can't you run a driect drive gear box on it? Thats how thay do it when that use helicopters motors on real cars and motorbikes.Are the RC turbines diffrent then the full size?Are heli turbines diffrent then the others? Thay showed a truck and bike with heli motor on Hourse power TV and Discover channel.

EddieWeeks

09-13-2004, 02:58 PM

Because its turning way too fast and you just can't conect anything to it
without viberating.

Jetcat built this

http://jetcatusa.sitewavesonline.net/hp5.html

but they had to limit the RPMs to 80,000.. At these lower RPMs they can
only get ~5 shp... still a lot but nothing like the ~20 air hp at full rpms.

The correct way to do this is with a second stage turbine with its own NGVs
(nozel guide vanes) and own shaft... Simjet of Denmark did this with a P80
size turbine and made 20 kw of power with a 5 lb turbine... The gear box and generator
was ~10 times larger than the turbine and the fuel consuption was ~10x more
than a cheep gas generator..

No.. I going to stick with a cheepo padel wheel for now.. The big advantage is
I will be puting power to the wheels from 0 mph to top speed mph...
That is something no gas or electric can do over such a large range of RPMs..

Eddie Weeks
http://www.corpcomp.com/weeks1/

e_lm_70

09-14-2004, 09:33 AM

The correct way to do this is with a second stage turbine with its own NGVs
(nozel guide vanes) and own shaft... Simjet of Denmark did this with a P80
size turbine and made 20 kw of power with a 5 lb turbine... The gear box and generator
was ~10 times larger than the turbine and the fuel consuption was ~10x more
than a cheep gas generator..

From where does it come your 20kw power for this case ?

They state : http://www.simjet.com/turboprop.htm
that it provide just 7 HP (around 5Kw) ...

To me it sound an expensive way to get "little" power !

BL look over this edge ...

e_lm_70

EddieWeeks

09-14-2004, 01:54 PM

Lars (Simjet owner) told me years ago, they used a SimJet3000
witch normaly produces 30 lbs of thrust to run their generator...
The turboprop uses a much smaller 12 lb.
He showed me the second stage turbine wheel they came up with
to extract the power.... It was only a few mm different in size than
the one I designed and had made..

Eddie Weeks

thefasttrack

09-20-2004, 03:41 PM

lets see thos pics

BMP Racing

10-02-2004, 11:31 PM

Are you currently buying your turbine wheels? I have several good friends in the turbo business. One of them would probably hook you up. Let me know.

Brad

andrew 630

03-23-2005, 08:24 AM

I'll take some new pics tonight..

Eddie
Hello everyone, I'm new at the forum! I'm going to be involved in the race though not with a turbine powered car (mainly for financial reasons and low availability of jet stuff at my area).Eddie ,I don't know how your project is going at the moment i write these.I hope the following would be of help (if you're still working at it !)
-First of all,shifting from the turbocharger impeller to the paddle wheel you scetched would most likely decrease performance.consider the turbocharger impeller as an outcome of serious engineering design ,built for the purpose you also have: to "steal" as much energy as possible from the turbine's exhaust gases and transform it to useful torque
-however, the impeller is almost useless if used without its casing.(Your configuration apparently feeds gases to only few blades at a time while the other blades simply wait for their turn to face the turbine's exhaust!!) A casing is there for one main reason:to pick the flow of gases and deliver it EQUALLY AND WITH THE CORRECT DIRECTION to EVERY blade of the impeller.For this reason ,the shape of the casing looks like a snail ! Gases enter the casing in a circumferencial direction through the large cross section and (as they are gradually "absorbed" by the successive blades they "meet" ) the cross section of the "snail" becomes smaller.At the same time, the gases flow between the blades from the circumference(where they entered) to the center (where they exit in the axial direction).
-.personally i would go for it if i had a model jet engine.If I had a turboprop(for airplanes) or a turboshaft (for helis) i would install these of course!(They only need gearing system, no additional impellers)
Since however you decided to go the hard way, in my opinion you will definitely need to incorporate a casing for your impeller. Of course the initial casing you stole the impeller from is too heavy as you mention.(just to be sure :are you sure you haven't removed the compressor half of the turbine-compressor pair;)Anyway, instead of asking your cnc buddy to make you a new paddle wheel, you could join your welding skills and create a simple snail- like case for the impeller made out of ,say, 2mm thick stainless steel .Take ideas from simple yet quite effective casings of centrifugal air blowers.The idea is to use a casing with the same geometry principles as the original(in order to operate as described above) but so simple (as an extruded 2-d object) that YOU can construct it and it will be light enough.
Know i've been too long, hope you read my reply and come up with something really killer!!!

fastrc

03-30-2005, 08:34 AM

[QUOTE=mtrsprt]It was mostly an educated guess, but transfering kinetic energy to mechanical energy is a huge loss.

It may be a huge loss of efficiency, but it is a huge gain in power and speed over nitro or electric engines. Have you seen these fancy tractors used in tractor pulls? Lots of them have jet turbines in a simiar setup like Eddie uses, and they've got to be powerful to pull that much weight.

cool head

03-30-2005, 10:01 AM

fastrc

03-30-2005, 10:32 AM

[QUOTE=fastrc]

true, but seldom do turbine pullers win over IC engines. don't think turbines can produce enough torque.

Coolhead I think your trike will be extremly fast very good chance of winning the contest and getting in the record books, but a turbine powered car sounded like a really good idea to me if you could get it up to speed in the required time.

cool head

03-30-2005, 08:19 PM

thanx for the props. i just dont see the turbine producing the torque thats required to get to 100+mph. i've done 20-30 runs and i'll tell ya its a struggle to get past 100. it was dificult for 1 engine with 1:1.2 hp/wt ratio to accelerate to top speed. the problem is with the high gearing it's difficult to get an engine to its peek power rpm. i found that it takes 3 hp to get to 100mph and 6 hp to get to 120+mph. electrics are going to be hard to beat. but my theory is, elect make most power at low rpm and decreases with rpm. nitro engine increase power with rpm,

hmmmm, i'm just rambling. i still would like to see a tubine car at the event though.

Dagger Thrasher

03-31-2005, 05:41 AM

Wow this sounds like an awesome project. Just a small suggestion though...if you have problems with heating up/melting the bodyshell, you could just use some of this Losi Heat Shiled stuff: Losi Heat Shield Adhesive Nomex (http://forums.radiocontrolzone.com/showthread.php?t=193093)

Keep up the good work :)

FreeRideJunkie

04-01-2005, 11:48 AM

I do agree with the idea of your shroud possibly being flawed. You are only using about 35% of the blades at any one time... the other 65% are dead weight spinning at that time. To make it more efficient you need a shroud that looks like today's conventional turbos on cars. This will allow all of the blades to be working at once and then the exhaust to exit out of the side (doesn't break the thrust rule). You could also direct it up if you so desired. Just my .02. Looking great though and I can't wait to hear the sucker scream.

EddieWeeks

04-05-2005, 03:05 PM

After reading everyones thoughts... I would say I agree with all of you...
There are many ways to make the paddle wheel / turbine more efficient,
but there is a major problem you may not be aware of...

This engine eats about ft^3/sec of cold air and puts out about 9 ft^3/sec
of hot air..... If you back pressure the core, it may only put out 8 ft^3/sec
then it over heats...

So you see what ever I design and build HAS to let all the air out without
too much backpressure... One good thing is the velocity of the hot air is in the 700-900 mph range. The design of the paddle wheel has an adjustable
flap on top to force more or less hot air through the paddles...

I told Darren.. (Machine shop owner) to just sit on it till they find a
location for the race... Meanwhile I have been flying that turbine in
an airplane till I need it...

So when they set a date.. I will be there...

I doute it will go win anything but it will be ... by far... the coolest car there.. !! or hotest..

Eddie Weeks
http://www.corpcomp.com/weeks1/