MPH Challenge

[Tankdg]

I will have look up that thread

[dukeaholic]

AWESOME build!!

[1979chevy.]

AWESOME build!!

Where have you been haha, just kidding man it is an awesome project.




God answers prayer,pray,believe,NEVER GIVE UP!!!

[davidemaxx]

where is snook?

[humayrayakongkinaon]

his probably taking a day off to go black friday shopping with his family.

[Snook Man]

It would take RC products/parts at 75% off to get me to fight the crowds on black Friday…

I have been trying to figure out a way to use the same body with single or dual engines and making templates for the aluminum chassis and CF chassis side extensions.

Twin SB engines mounted at chassis deck height would keep the entire cooling heads completely covered, and twin BB engines would have only protruded out the top a little more.
I went ahead and lowered the rear body posts as low as I could but still allowed 3/4 inch between the body and the top of 6 inch diameter tires at full suspension compression (with shock limiters inside the shock body).

That allowed me to trim the bottom of the body close to where it will eventually be.
Even after lowering as far as I could the SB 3.3 heads only stuck out about ¾ of an inch.

I decided to make a scoop to see if I could design it to work with either twin SB’s/ BB’s or a single engine setup.

It should work OK and allow plenty of air to the heads. I will just need to make 2 more designs of the scoop, 1 a little taller for BB’s and 1 narrower for a single engine. I'm still not sold on the idea.

The outside edge of the red tape will be the outline of the main aluminum chassis.
Everything on the outside edge of the tape will be CF.


All components will mount on the main chassis. The CF plates will be to keep out as much air as possible from the underside and to have something to secure the sides of the body too. Without any bracing or the plates to support the bottom body edge it would probably start to distort at high speeds.

[stallion 63]

Looks like a space ship now,Snook.Careful,make sure it doesn't take off and never to be seen again.When will you finish this?Can't wait to see the vids.It's killing me.

[Snook Man]

When will you finish this?

Most likely will not see any run time until spring.

[Tankdg]

Snook, just a thought. I am thinking instead of scooping the air and routing it into the body how about dishing out the body? You could make an upside down tunnel or sorts.

[IMG][/IMG]

[Tev364]

that actually looks like a good idea but it still does the same thing and both ideas add drag and can potentially make the front end lift because of the parachute kinda effect

[Tankdg]

I am thinking that by allowing a space for the air to flow through the cooling fins without getting into the body it will minimize the drag. Snook could create a structure to seal the cooling channel from inside the body with some foam tape.

[Snook Man]

Snook, just a thought. I am thinking instead of scooping the air and routing it into the body how about dishing out the body? You could make an upside down tunnel or sorts.

[IMG][/IMG]

That’s a good idea and I almost redesigned the body like that, but with the tranny mounted on top of the chassis the spur gear is only about ½ inch from the body as it is.

The most convenient way I see atm is to just use a scoop. Hopefully with the rear completely open the air that gets in can get out easily and not cause too much drag or create too much lift.
I don’t think there’s anyway to know for sure until I run it up to speed.

I’ve set the body aside for now to concentrate on the chassis. Don’t need a body if I can’t go fast

I’ve also come up with an idea for different chassis bracing that should work better.

[Tankdg]

I see your point about the trans.

[spencer_lee1993]

Hey Snook, what if you made the air filter and the engine head stick out of the body, and keep the body as sealed or as close as possible to the head and air filter tube, then you wouldnt have to worry so much about air underneath the body.

[Tankdg]

Another thought-Direct drive, sort of. What is the normal RPM of the 3.3? I am thinking a dogbone with a gear one end meshed between the clutchbells and cupped to the diff on the other end. You already have the clutch in the clutch bell so do you really need the slipper clutch too? You would need 1 or two carrier bearings but it would eliminate the need for a trans and would open up the body to all sorts of alterations.

[2010450x]

It would literally be just like a real Nitro funny car then. Could be a pretty sweet idea

[Snook Man]

With the final drive ratio/roll out needed to even get close to 100MPH direct drive would be out of the question.
Unless you are willing to come push the rig up to about 60mph before the engine can take over that is…

[Snook Man]

I have pulled out my Ace in the hole so to speak for this build.

I spoke with my wife’s uncle who has worked for Pratt & Whitney in experimental Jet propulsion for 30+ years and he gave me a few ideas as well as some guidance as far as basic aerodynamic.

I sent him a few pictures of the chassis and body which he then showed to a few others with even more aerodynamic experience than him.
Basically the consensus was if I use the scoop to let air for cooling and engine intake in, I have to have at least 2.5x the size of the scoop opening in the rear of the body to let the air out or strange things will happen (he used a lot of big words that I couldn’t even spell)
With the rear of the body completely open I should have no problems with the parachute effect. The spoiler will create a vacuum effect (negative air pressure) directly behind the body which in turn helps to draw the air entering through the scoop out the back.

I also asked about the chassis side plate extensions as to if they were needed or not to keep the air out so I could reduce the total weight and not have the cost of the CF needed to make the plates. All agreed that if left open the turbulence created would play a factor and the amount of air let in would have to be calculated into the area of the opening to let that air out.
He recommended just making the side extension plates out of aluminum in a web design as light as possible and then cover the plates with a self adhesive shrink wrap that they use on occasion.
I asked if he thought shrink wrap would hold up to 100mph, he and said not the ordinary stuff, but he would send me a roll that would.
After talking with him I started thinking again and now I’m wondering if I can make a light weight body frame and shrink wrap it. The more I think, the deeper the hole gets

I mocked up a different rear chassis brace and transmission mount as 1 piece that should work pretty well to stiffen the rear of the chassis and a front brace that will tie the transmission idler block to the front suspension and throttle brake servo. The bellcrank for the throttle/brake will now just mount on top of the brace. If needed, I can add some supports between the top brace and the chassis deck for more stiffness.
I also cut out one side of the chassis plates to get an idea of how it would look.
If I use 2mm aluminum for the plates it shouldn’t add too much weigh at all and will be much cheaper than carbon fiber plate.

[Tankdg]

I am sensing flaming tire marks on the road just before the car disappears in brillant flash of light.

[Rick's Revo]

I am sensing flaming tire marks on the road just before the car disappears in brillant flash of light.

Snook, I just read all 5 pages. I am impressed Sir!

Tank, I think you're right. The Flux Capacitor will fit nicely under there. I am sure that Snook could adjust it to time jump at 101mph instead of 88mph to win the bet.

[lubecakes]

I'm quite impressed! I gotta say though, traxxas beat you to it with the Xo1.....well as long as the person driving the Xo1 has an ipod touch or iphone.
Either way it's a bad cool project, and you can't beat the satisfaction of doing something like this yourself.

[Snook Man]

Yep, beat again by a flashlight

I am glad to see they got a 10+ lb rc to hit the century mark. It gives me more confidence for the Nitro seeing it should only weigh in at under 7lbs. I may not need the Flux Capacitor after all

[stallion 63]

Snook,just a pointer.With your engine set up,the stingers on the pipes are facing forward and will restrict the out flow of the exhaust and stifle the engine.
I suppose you'll be using deflectors to point them back wards,right?
Btw,what pipes are those?

[Tev364]

this guy on youtube did 93mph with a jato without a body so i know you can get the 100+ mark easily check the vid

http://youtu.be/r3IErjkdH8Y

[08kgraves]

man that jato sounded a little lean when he first went off to the right.

i always wondered what little gps people put on there rides....... what do you use snook?

[Snook Man]

Stallion,
Those are just stock savage pipes (I won’t even run them on a savage). Just using them for mock-up since they are long and I want to make sure I have plenty of room for the pipes I will eventually use (undecided as of yet).

08,
I normally use a Garmin Nuvi gps on the Maxx for speed runs. But for this I will probably purchase something smaller and lighter in weight.
I’m 99% positive that I have permission to use an air strip for testing and also to have a friend in the police force radar the rig for 2 comparable mph readings.

[Tankdg]

I bet one of those Garmin Forerunners is going to be about as light as you will get. They are usually all over ebay.

[Nitronaught]

I have pulled out my Ace in the hole so to speak for this build.

I spoke with my wife’s uncle who has worked for Pratt & Whitney in experimental Jet propulsion for 30+ years and he gave me a few ideas as well as some guidance as far as basic aerodynamic.

Yeah but does he have 2 leaf blowers as a wind tunnel? If he doesn't I'm not impressed.... j/k

This thing is really developing.

As far as the 100 mph mark, That's with an electric, I still think Snook is going to surprize us all with a video of a 100+mph pass with a nitro RC..... That's something!!!! Really impressive..

As far as the cooling? I wouldn't be too concerned. It's not like you are going to be running this for a full 110 cc's of fuel..... I really wouldn;t worry about the cooling, you can actually make up for it with a longer header to help disappate heat, or a larger cooling head to make up for any lack of air flow. But like I said I don't think it's a big concern.

Keep us posted Snook!!!!

[jekyll818]

How about just cutting a circle out in front of the engines? The body slopes downward so it will expose the heads to some nice cool air, and it isn't as dramatic as tank's suggestion.


You might could even mold something to fill the hole up until it intersect the heads to make the air less turbulent. And I definitely agree with having an outlet in the rear of the body.

[2010450x]

But wouldn't that much air just cause unneeded drag? Like NN said, it wont be running long enough to really worry about over heating

[MaXXerBaSHer]

If you need some extra speed just find a big hill

yay 100 posts

[1979chevy.]

Yep, beat again by a flashlight

I am glad to see they got a 10+ lb rc to hit the century mark. It gives me more confidence for the Nitro seeing it should only weigh in at under 7lbs. I may not need the Flux Capacitor after all

No, you weren't beat. As you know the XO-1 is an electric vehicle. Yours has engines in it
If you get this thing to hit triple digits than you have accomplished something, you've already accomplished much with the fabrication of the body and chassis.

Can't wait to see this thing run


God answers prayer,pray,believe,NEVER GIVE UP!!!

[TMaxxer]

I just seen that XO-1 on yahoo news today..

http://autos.yahoo.com/news/the-supe...or--1-100.html

[rcdriver5]

Snook, have you thought about contacting a funny car builder about aerodynamics? I grew up around them and know that they design everything so that they have the right amount of downforce/drag so that they have the possibility of reaching over 300 mph. You may just get hung up on because of how busy they are right now during the off-season, but if you could get any tips, that would help a lot

[davidemaxx]

Another thought-Direct drive, sort of. What is the normal RPM of the 3.3? I am thinking a dogbone with a gear one end meshed between the clutchbells and cupped to the diff on the other end. You already have the clutch in the clutch bell so do you really need the slipper clutch too? You would need 1 or two carrier bearings but it would eliminate the need for a trans and would open up the body to all sorts of alterations.

thats a good idea and it wouldnt need to hit 60 mph with the clutch bell it would allow it to start at a lower speed

[Snook Man]

I don’t think you guys understand the torque that would be needed to hit 100mph with direct drive.
That would be like trying start from a stop in a 1:1 standard transmission car while in 5th gear.
It just doesn’t work, not to mention the stress on the engine and clutch.

[08kgraves]

i do, thats why i never said anything about it lol

[2010450x]

yeah you make an excellent point. I guess I should think then talk. not talk then think lol.

[Snook Man]

Aluminum on order for the chassis

[Nitronaught]

Snook, have you thought about contacting a funny car builder about aerodynamics? I grew up around them and know that they design everything so that they have the right amount of downforce/drag so that they have the possibility of reaching over 300 mph. You may just get hung up on because of how busy they are right now during the off-season, but if you could get any tips, that would help a lot

I would think getting with someone who deals with top speed records would be the direction to take,,,, 1/4 mile drag cars need a lot of downforce so they can get to top speed in a short distance, this requires a lot of traction....

Hey Snook, Looking forward to seeing that chassis.....