Landracing Forum
Tech Information => Aerodynamics => Topic started by: robfrey on February 20, 2013, 12:20:48 AM
-
Looking for a nice clean way to activate our cut off switch for our # 496 liner. Any ideas?
-
Flaming river remote unit, it has a rod that activates it. A quality part! I have had a cheap kill switch short out and blow a hole in the metal housing.
-
Rob, ours is on the push bar, cable operated to the front of the car where the battery and switch are.
-
The 444 Vesco liner has a push rod in the nose and a cable pull to the driver, a single lever is all that's required.
-
Rob, ours is on the push bar, cable operated to the front of the car where the battery and switch are.
Isn't that kinda rude calling the safety guy a jerkoff? :-D
-
not to mention it may be painful! :-o
-
Rob, ours is on the push bar, cable operated to the front of the car where the battery and switch are.
I like that. I figured we would do it cable actuated to a flaming river switch which should be here today but was not quite sure how the actuator would work.
-
Flaming river remote unit, it has a rod that activates it. A quality part! I have had a cheap kill switch short out and blow a hole in the metal housing.
Oh yeah! No cheap switches here. I once watched a guy chase electrical gremlins for an entire season never making a good pass. Problem eventually traced to old cheap corroded cutoff switch which kept braking contact. I bet that cheap switched cost him thousands not mentioning the embarrassment of not making a good pass for about a year! That cheap switch was quite expensive!
-
How many times do you hear of problems created by parts like that. We always look for the big thing that went wrong. It happens to all of us at some stage.
-
Switch setup with custom arm and dual cables. One out the back, with the other for the driver. I mount the switch next to the battery.
Hope it helps.
-
Thank Joe. I do plan to use cable system but I don't want to drag a handle like that through the air. I looking for a clean actuator that can be recessed into the bodywork or something.
-
Just add an aluminum post to the cable end. I buy my cables from www.surplusunlimited.com in Daytone Beach, a couple of blocks toward the ocean from the 500 Track. The 33C are the red Morse cables... less than the race supply houses.
-
Maybe consider this:
http://www.flamingriver.com/index.php/products/c0015/automaticbatterydisconnect/FR1052
-
Rob, that cable system looks good. Couldn't you configure it to be a pull instead of push?, then you could countersink the handle with enough space around it for a good finger grip. A few tenths lost speed wise is worth the safety aspect. I'm going to use Joe's setup for sure. Thanks Joe, great system.
-
Rob,
How about welding a tab down off a hartwell latch.
-
Rob,
How about welding a tab down off a hartwell latch.
I was thinking of this at my desk, I am going to play with the idea when I get home tonight.
-
To make it a pull, just run the cables the other way!
-
Mount the pull/push handle in a recessed space similar to a NACA duct.
-
Mount the pull/push handle in a recessed space similar to a NACA duct.
Too turbulent. Think smoother.
-
Rob,
How about welding a tab down off a hartwell latch.
I was thinking of this at my desk, I am going to play with the idea when I get home tonight.
Tman, did you come up with anything?
I was thinking of fabbing a 1.5 wide x 8" long flat rocker rocker switch that would sit flush when switch is in the on position. Maybe I can make the handle part itself extra thick (maybe 3/8" aluminum) so that it can stick up above the body work a bit then be contoured to match the body within a few thou using a flap wheel.
-
On our roadster build we are going to use a solid state battery isolator and use a flush mounted push button. Tony
-
solid state battery isolator
Tony, which one?
-
Why not make the rotary switch lever out of aluminum that is formed into a thin airfoil. It would be at right angles to the body but in the "ON" position it would be parallel to the airflow so its drag would be almost nil. The "OFF" position would be high drag but who cares?
Regards, Neil Tucson, AZ
-
Why not make the rotary switch lever out of aluminum that is formed into a thin airfoil. It would be at right angles to the body but in the "ON" position it would be parallel to the airflow so its drag would be almost nil. The "OFF" position would be high drag but who cares?
Regards, Neil Tucson, AZ
The problem with this idea is a problem of position. Due to real estate reasons the battery needed to be in the front of the car. Switch should not be positioned in front of the widest part of the car as it will disturb laminar flow. We did not want to run wires all to the back of the car then all the way back up to the front to all the electronics. It is safest if the switch is as close to the battery as possible.
-
A small thin airfoil should not disturb the airflowat all....?
Regards, Neil Tucson, AZ
-
Rob,
http://www.hartwellcorp.com/pdfs/Hartwell%20Corporation%20Brochure.pdf
page 4-6
Should give you a pretty good idea of what I was thinking.
-
A small thin airfoil should not disturb the airflowat all....?
Regards, Neil Tucson, AZ
Bugs disturb airflow.
Any protrusions at all off the fuselage will create a wake on a high laminar flow body making the whole shape a bit less efficient.
-
Javier. Could I also use this to reset the switch or would this be a one way only thing?
-
solid state battery isolator
Tony, which one?
I have the one made by CRATEK http://motorsportcables.com/content/battery-isolation , but there are plenty of companies that make inexpensive units. Tony
-
Bugs are not airfoils, ... at least the bugs that I've seen. :-D
Regards, Neil Tucson, AZ
-
Rob I would think about putting the switch directly in your line of sight just in front of the canopy. I would use Neal's air foil as the activator let it have a little free play on either side of on---and
wallah you have a built in yaw indicator as well as an frt sight to point at some horizon feature. any airstream disturbance should be minimized in that position!
-
Javier. Could I also use this to reset the switch or would this be a one way only thing?
I'm sure you could. Weld a tab down off the lever, slotted hole for cable to allow the slack to pop up. Enough lever length to positively activate switch lever in both directions.
-
one more link of same style latches from mfg Avibank
http://www.avibank.com/index.cfm?fuseaction=home.prods&product_id=45
-
Rob,
How about welding a tab down off a hartwell latch.
I was thinking of this at my desk, I am going to play with the idea when I get home tonight.
Tman, did you come up with anything?
I was thinking of fabbing a 1.5 wide x 8" long flat rocker rocker switch that would sit flush when switch is in the on position. Maybe I can make the handle part itself extra thick (maybe 3/8" aluminum) so that it can stick up above the body work a bit then be contoured to match the body within a few thou using a flap wheel.
Playing with a hartwell latch on the desk you could easily trip a heavy duty switch with one.
-
Pair of ideas which are closely related.
1. Have a spring loaded panel behind the main switch that allows you to get you fingers under the switch and pull it up.
2. Have a panel that you push down to trip the switch. This could be an insert type panel that you push down and it releases the latch and pops up or a whole panel area that you mash and and it trips the switch.
Now I doubt with the stringent aerodynamic rules you are imposing that you'd want a whole panel you mash since someone might miss and dent the fuselage, but a 2x8in panel in constrasting colour that you push or has the trailing edge inset to pull and a reinforced frame would prove pretty resistant to rough handling.
-
Both those companies have flush handles that pop up and then you turn.
Geo
-
Put it behind a flush mounted door, similar to the electric canopy switch or the emergency canopy jettison handle on the A7-E. Labeled properly of course.
Wow, never thought that would be needed again. (thirty years)
-
What did you come up with?
-
Still have not made a decision yet. Sort of put it on the back burner for now.
-
That is understandable. Something will pop into your head when you least expect it. :-)
-
+1 in the Cartek Solid State unit.
jon
-
Wondering what might have come of this. Any updates?
Mike
-
(http://img.tapatalk.com/d/13/11/29/3ahu6umu.jpg)
Works pretty good. I have the dxfs to make these if anybody else wants them.
-
Where is the switch located on the car?
-
Left hand side of the car above the wing.
So the left side of the picture is forward.
-
Where is the switch located on the car?
Rick,
Here is a pic I took that shows the location of the switch Rob was telling you about:
(http://i947.photobucket.com/albums/ad318/GKABBT/Wilmington%2009282013/IMG_0015_zpsb8c3e0dc.jpg)
Hope this helps,
Gregg
-
The rule book says must be mounted in the front or the rear of the vehicle. The reason is if a vehicle is on it's side or top it may not be accessable to the emergency personnel. The inspection committee might turn your vehicle down or make you change it at the event.
-
EDIT: I guess Glen posted while I was typing but will leave the post up as I spent so much time typing :cry:
=======================================================================
(http://i947.photobucket.com/albums/ad318/GKABBT/Wilmington%2009282013/IMG_0015_zpsb8c3e0dc.jpg)
Before going to the salt, while at the Roadster show possibly, run that position by one of the tech guys. One of my good friends, I won't mention names Sparky, had his new car at El Mirage and had to move his switch since they told him the switch should be at either the extreme front or extreme rear of the car. I'm not sure of how close to the front or rear is considered 'extreme'. It would be a shame to get to tech on the salt and then have to go work on the car over that issue. You might be fine where the switch is located and maybe have already run this by them and if so sorry for bringing this up.
Great work on the switch and you are not leaving any aero on the table :cheers:
The rule book doesn't clarify exactly what 'extreme' is but does say...
The disconnect switch or a positive mechanical control (cable or rod) for the switch shall be located on the front or rear of the vehicle operable externally and clearly marked.
He was told that it was ok to mount a solenoid like a Ford type at the batteries with an electrical switch operating the solenoid at the back or front of the car.
Since I got side tracked into boats and they have regs I'm going to do my batteries like on the boat where you have to have a fuse within 6 inches of the battery. You can get these fuses...
(http://www.genuinedealz.com/media/catalog/product/cache/1/image/9df78eab33525d08d6e5fb8d27136e95/B/l/Blue_Sea_Systems_5191_12.jpg)
(http://www.genuinedealz.com/media/catalog/product/cache/1/image/9df78eab33525d08d6e5fb8d27136e95/B/l/Blue_Sea_Systems_2151_12.jpg)
...that work off of the post and they come in sizes large enough to handle any load. They are not that expensive....
http://www.genuinedealz.com/marine-electrical-supply/fuses-and-blocks (http://www.genuinedealz.com/marine-electrical-supply/fuses-and-blocks)
... and just might stop a car from burning down,
Sum
-
Rob, the reason I asked was that my liner shut off is in the front third of the car, but not extreme front. Actually in the very front of the foot box near the driver. The rule books do not specify "extreme" front, and I have seen other streamliners that used a door for access.
Like you, I have the entire electrical system fused with a 400 amp fuse.(just enough that engine starting wont blow it) Any short to ground will pop the fuse as well as complete deactivation from the drivers steering wheel thru an automotive solenoid. I really thought I had it covered every which way.
The electrical switch is push to de-activate, but to reset, the hatch is necessary. I suspect most liners have switches that are hidden from the air but can't really remember specifically what cars.
At any rate most liners also if they are on their roof, will need to be up righted to open or cut canopy and cage since most are hinged. I realized they made Sparky change to extreme end, but if the rule book changes don't specify extreme ends of the vehicle...???????there is room for the shut off being "near" the front or rear as you and I have done.
I seldom disagree with SCTA/BNI rules since they are all about safety for the drivers and I am seriously in favor of overbuilding, but there are so few liners I think the safety crews will become acclimated to each specific location. Perhaps not.
I will work on "Plan B" however not a simple thing with my current body design. (both ends are complete enclosures.)
Love your car, and hope to see it run blindingly fast.
-
Can we see a picture of the whole car?
-
RR
Sorry the front is coming along with the design that is shown in the attachment, but the stylist/designers that I have had working with me don't know how to listen to me or the WindWizard. Both have been fired. The guy that produced the current front is much better, but still issues with understanding what the engineer wants.
The first was a real pro "Ford Designer" and thought he was smarter than my aero guy. He got it wrong.
The rear will use some of the aluminum body that was present on the lakester. It is good, fits extremely well, and will accommodate my composite panels for compound curves. I have not begun that yet, as LIFE got in the way for the past year. and more....
As a lakester we were on the salt in 04 testing. Not a fast session but I learned a lot about how smart I'm NOT.
I plan on running at Wilmington ECTA next summer with partial body, starting at the front and working my way back. Perhaps being at WOS next year. Financially though I'm not sure. In the same boat as most.
The car is considerably smaller than it looks in the photos. 21" wide thru the driver bay until the rear fenders begin.No scoop on the car and provisions to change vert fin from nothing to what size becomes necessary.
Objective 300 MPH+but not much more
-
Rick, just to clearify...
2013 SCTA rule book, page 36. 3.K, last paragraph.
"All vehicles shall be equipped with a main battery disconnect switch. The dissconnect switch or a positive mechanical control (cable or rod) for the switch shall be located on the front or rear of the vehicle, operable externally and clearly marked."
-
Due to the design if our car, it will probably never lay on its side after an accident. It will probably right side up or upside down. If it is upside down, it will be harder to get to if it is located at the very top of the vehicle. Reading the rules, I would have to say that we comply. Keith Turk is an official SCTA inspector and he had no problem with location. That being said, I want to get the car looked at by another SCTA inspector when we are in CA in January so we minimize any surprise issues that we may encounter at SpeedWeek. Oh yeah, Brandon also wants to get his bail out signed off while in CA.
-
I was on the SCTA/BNI Emergency Response Team for several years and been on many accidents. When a vehicle crashes ,1st. it won't look like it did in inspection and the emergency people don't have a lot of time to look for a switch under a door no matter how well it's identified. The Vesco liners have a push rod right in the nose with a pull cable. This simple rod to push the switch off. In many cases the body panels are crushed or torn off. Think about it. Just my thoughts.
-
Glen, there is no door, you just press where it says to. No protruding handles or rods to snag if car starts rolling and sliding. This design is probably MOST likely to survive an accident plus the inertia switch should have done its job.
-
This does have me thinking. I need to put stickers on the bottom if the car showing where shut off is in case car is upside down when they get to me.
Also, is it ok if I make my own much bigger decals telling where the switch is or does it have to be the little round SCTA sticker that you write on with a sharpie?
-
......but there are so few liners I think the safety crews will become acclimated to each specific location. Perhaps not....
I doubt that most of the safety crews on the course have seen many if any of the cars that are running during inspection or any place up close unless a car really interests them. I'd not want to count on the fact that they did or even if they did if they remembered where the switch was on any particular car. I'd say the rule is a good one and isn't that hard to comply with. If there is an electrical situation going on after/during an incident you don't want to wait for the car to be turned over to deal with it,
Sum
-
I wonder if the AMO/STEELE liner had a functional electrical cut off switch after crashing?
If the Hondata car had had an electrical cut off switch on the front. Guess what.
As in the past I will comply with the rule, but Isolating the battery energy source isn't all about a solenoid and switch.
Rob, I think we both have to change. Keith will be over ruled and over powered. I will keep my switch and access door, and add a switch at the front of the car. AND identify the location on top and bottom of the car.....
Sum, if the rule was good it would also require fuses on the electrical system so that if a 00 battery wire got cut and grounded in a crash, the whole chassis would be re welded...or somethin like that.
Anyone that has seen the cars I have built and/or been involved with, SAFETY has been paramount. Hell with some minor tweaks the cage I did for the Merkur 25 years ago would pass tech today. I think Mike is doing those tweaks. Every car I have done has gone thru SCTA tech successfully the first time.
-
....
Sum, if the rule was good it would also require fuses on the electrical system so that if a 00 battery wire got cut and grounded in a crash, the whole chassis would be re welded...or something like that. .....
I agree and plan on using them.
...Anyone that has seen the cars I have built and/or been involved with, SAFETY has been paramount. Hell with some minor tweaks the cage I did for the Merkur 25 years ago would pass tech today. I think Mike is doing those tweaks. Every car I have done has gone thru SCTA tech successfully the first time...
Yep, I'd have no concerns getting in any car you've made and can't wait until you get the changes done to the current one,
Sum
-
Rick,
I don't know about moving our switch. As I read the rules, we completely comply. Let's see what the inspectors have to say.
If I were to move the switch to the rear of the car, it would not be nearly as safe. The tail can be broken off our car in a crash leaving the switch useless. Also, it has a chance if getting tangled in the chutes. I will debate the issue that our safety cutoff switch is actually in the safest, most readily available position possible on our car. I have a lot of thought into this detail of our design. It's engineering in both design and location was one of things that kept us from be ready for Speedweek as we knew this could not be rushed.
-
I had our battery cut off on the fairing all most to the rear of the car (roadster) they asked me to move it to the rear of the car for the next meet. They also did not like the push rod I had connected to the switch, the rod was 3" long. It was no big deal I moved it put a big sign on it and they still hand me a round sticker to put on top of the car by the driver with an arrow to the rear.
Richard
-
The one small problem is that I have no flat panel at the rear of our car. Everything comes to a point. I don't want to stick some knob out the back if my car when we have taken the pain that we have to minimize separation drag. And yes, it matters! Alright, enough on this subject until a SCTA official chimes in.
According to 36.3k we are compliant.
-
Rob I'm not an SCTA official but I know that in a wreck or fire the rescue guys will first go to the extreme ends of the vehicle looking for the power switch. The longer it takes them to find it the longer your sitting in your car waiting for someone to help you.
-
Well I guess we are completely screwed because there no way this can happen. I wish they would have been more specific in the rule book. Oh well.,
Sort of ironic as you influenced the location of the switch. You described most Streamliner accidents to me years ago as accidents start out as a pencil roll then finish with pogo sticking . We if this true, there will seldom be a switch to shut off when they get to the wreck site.
-
TRUE
-
Here is the battery shut off on my brothers streamliner, it is the ring just visible at the lower corner of the fin. Passed 2013 tech
-
Here is the battery shut off on my brothers streamliner, it is the ring just visible at the lower corner of the fin. Passed 2013 tech
Nice!
Let's see some more if that car!
-
Here is the battery shut off on my brothers streamliner, it is the ring just visible at the lower corner of the fin. Passed 2013 tech
I like the color :-D
Can not imagine that the tail, alone the pull ring would be there after a crash or on any car for that matter.
-
Well I guess we are completely screwed because there no way this can happen. I wish they would have been more specific in the rule book. Oh well.,
Sort of ironic as you influenced the location of the switch. You described most Streamliner accidents to me years ago as accidents start out as a pencil roll then finish with pogo sticking . We if this true, there will seldom be a switch to shut off when they get to the wreck site.
Rob I agree but I'm just telling you what I see
-
..Well I guess we are completely screwed because there no way this can happen. .....
I realize that you must be down about this, but there probably hasn't been one of us that hasn't had to change something on the car that maybe we felt was ok. We all give up something aero wise because of a rule.
(http://purplesagetradingpost.com/sumner/bvillecar/carbinite-496%20streamliner.jpg)
How about a rod with a ring on the end of it near where the arrow is above. That area right behind your flap would probably not be effected much by something like that aero wise. Run it by them if you think it would work. No it isn't at the 'extreme' end of the car but at least behind the wing/axle configuration and awful close to the very back.
A fuse at the battery and the cable to the switch or run the rod forward under the skin to where the present switch is or rod to morse cable to do the same?
You have a ton of great engineering and construction in the car, I'll bet you will soon have a handle on this,
Sum
-
The switch on the liner survived my incident... it was mounted in the structure.. the body with the location information didn't. But it didn't need to, the switch turned itself to off during one of the many smacks the tail took before that part of the structure broke off. Most of the power cables ripped off as well.
The Lakester has the power switch integrated in the push bar, slides to the rear, takes a good jerk on the handle to pull it off. Labeled on the body and the handle... will the body be there... my experience tells me probably not... will the structure it is mounted to be there... I hope we never have to know
-
How about if we make the pushbar double as the shut off? We can make a 1" dia bar that slides in a 1.50 od x 1.000 id receiver with stop machined inside to keep it from pushing too deep. The 1" diameter stinger will be tapped 10-32 to accept the cable end. Basically you can grab the stinger and pull the switch off.
I don't think it is as safe as what we have but if it makes the correct people happy, we can do it.
-
Nice!
Let's see some more if that car!
Here ya go!
-
Nice!
Let's see some more if that car!
Here ya go!
I split this post off so that we don't get too far off topic. It is such a great car I think it deserves it. The new post is here.....
http://www.landracing.com/forum/index.php/topic,13398.0.html (http://www.landracing.com/forum/index.php/topic,13398.0.html)
Sum
-
Rob, saw the back of the car in another thread without the body, looks like there is structure in the stinger that could be used to relocate your switch if required. I agree with Sum, if it has to move to the back, I would see if they will allow it not all the way to the back.
-
Do you cut off the positive or negative battery cable? I have seen it done both ways.
Thanks,
Mike
-
Stainless, if necessary I can do what you did and make push bar the the handle. This insures that it will be at the extreme end of the car.
-
Do you cut off the positive or negative battery cable? I have seen it done both ways.
Thanks,
Mike
Electrically it doesn't matter at all. Whichever you choose, put the switch as close to the battery terminal as possible to minimize the length of wire that is still "hot" even when the switch is open. Protect any exposed terminals from getting shorted in a crash, whether from structure deformation or flying debris.
Regards, Neil Tucson, AZ
-
If you put the battery disconnect in the negative cable. It will allow you to connect any or as many power leads to the positive side of the battery as needed. (computers, data recorders, etc..