Road Horse Power
 

Earlier I posted my HP table and the formatting was all screwed up in the process. The relevant data from my HP posting is for the 80 MPH and 85 MPH data which I will now summarize.

At 80 MPH the truck naked gets 15.1 MPG which translates to 64.2 RHP.

At 80 MPH with aero appliances 18.2 MPG which translates to 53.3 RHP.

This means it took 10.9 less HP to do 80 MPH with the aero appliances added.

At 85 MPH the truck naked gets 13.2 MPG which translates to 78.1 RHP.

At 85 MPH with aero appliances 16.2 MPG which translates to 63.6 RHP.

This means it took 14.5 less HP to do 85 MPH with the aero appliances added.

The truck naked requires 53.5 HP to do 75 MPH v 53.3 HP to do 80 MPH/aero.

The truck naked requires 64.2 HP to do 80 MPH v 63.6 HP to 85 MPH/aero.

This is an 17% and a 18% improvement at speeds respectively with aero.

Soo technically you could also have a higher top speed? Isn't it that aerodynamics dictate top speed

High Speed Testing
 

Yes, my truck would have a higher top end speed. Aerodynamics is free HP. Phil Knox and I beleive that my F-150 should have a top end of around 150 MPH. Ford set a record of 148 MPH with a Raptor using 412 HP and my truck can produce 365 HP at 5000 RPM. At these speed regimes my aero should be worth 60 free HP. Such a test would require speed rated tires, and lubricant. It would not hurt to have a spare truck in case you blew yours up. That's where the deeper pockets Ford has is of critical importance. My aero needs improvements such as a belly pan, and boat tail extention but we beleive it could do it. In Texas there is a stretch of turnpike where the posted limit is 85 MPH and we could easily test 90 MPH out. A 100 MPH test would be nice to start forming a good graph curve. We think the engine would be in a very efficient place at 120 MPH but my current tires and limiter would not allow me to reach that speed. P.S. At 85 MPH my RPMs were 2,050.

I assume you are using a BSFC number to go from MPG to HP? You mentioned some numbers in your other thread that makes me think that. What are you using for the MPG (and/or fuel flow)? Just the truck's data via the OBDII port?

Are you using a single number for BSFC? Or do you have a map?

It's a useful way to think about the numbers no matter how you did it. Really shows what the aero is worth.

If your gearing is tall enough so that you could reach the higher speed without redlining the engine, of course.

Bsfc
 

Yes we are using .452 BSFC per HP hour for the truck. We are assuming gasoline weighs 6.138 lbs per gallon and that our drive line loses are .893. So for the 18.2 MPG at 80 MPH our formula is

80/18.2 = 4.395 x 6.138 = 26.98/.452 = 59.68 x .893 = RHP 53.3

These are useful working assumptions as you say. At 150 MPH the truck would have to get just under 5 MPG to make these numbers work. Phil has data that says these numbers change faster you go. The relationship is not fixed the faster you go. I would have to let him address that.

top speed
 

Here you can see the relationship between drag reduction,and engine rpm (top speed for any given gearing).
*The streamlining allows engine over-speed and shortened engine life,as well as lower BSFC.
*To get the best mpg,the gearing is altered to get the engine back to it's original BSFC island,which maximizes mpg.
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*If our estimates are within range at all,Aerostealth's F-150 might do 156-mph at standard atmosphere.

Thanks Phil. I worked up a graph on really large paper today showing HP on the vertical axis to 425 HP and speed on the horizontal axis up to 155 mph. It looks kind of empty with the data I have only up to 85 mph and 70 HP.

empty
 

I've got dozens of case files for higher performance cars,some of which can easily exceed 200-mph.Over the coming months we'll be able to reverse-engineer data from their published performance which will help us think about the 'Stealth F-150.'
Here's a higher speed table from HOT ROD Magazine illustrating performance for a car of 25-sq-ft frontal area,at differing Cds.
It gives you an idea of what the F-150 is going to be capable of as its Cd continues to fall.
http://i1271.photobucket.com/albums/...ntitled1-4.jpg
:D

Hey, Aerohead, is it possible to get the issue-number/month of that HOT ROD Magazine article where that graph came from?

issue
 

Yes,I'll snag that for next week.

Hot rod magazine
 

The article is "ADVENTURES IN AERODYNAMICS",Part-1,by Jack Heltemes,Page 34 (for the graph),HOT ROD MAGAZINE,April,1962.
This graph also appeared in the same article
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snow
 

We are having several inches of snow here in sounthern NM this morning. I had to take my daughter to work. I was managing 20 mpg in my big truck at 40 mph. Not bad for some of the worst conditions for mpgs. Top speed was 50 mph in places.

No electronic speed limiting in your truck?

speed limiter for F150
 

I beleive there is a speed limiter in my truck. I don't know what it is set for? My tires are only speed rated to 105 mph so it is probably right around that speed.

top speed
 

Somewhere I read 100-mph.

100 seems about right. I don't wanna see trucks going anywhere near 100 though, that can end pretty badly, since they have a higher center of gravity and are more affected by wind because of a larger total area. Handling on one would be pretty bad compared to an average sedan. 8th gen and maybe 9th gen Civics are rated for 130 MPH top speed, but stock they can easily go above 150, it would just take a while. The Odyssey is rated around 110 I think, but it's pretty scary to be going 95 in one.

100 mph
 

You should see our blogs and articles in Ev World about doing 100 mph with aero. Phil Knox co-authored them with me. One is titled 100 mph at 32 mpg and the other is an article on how these higher speed aero principles could be applied to trucks and buses at 90 mph.

I would have no qualms about driving my truck with aero at 90 mph. I have already driven it at 85 mph in West Texas where the legal limit was 80 mph and I got 16.2 mpg. I think with further improvements the truck could get 16 mpgs at 90 mph. By the way the truck was extremely stable at 85 mph but I was just testing for mpg data and as soon as I got it I slowed down to 80 mph. Then I passed 2 cops with radar in short order.

The truck was so stable at this speed I let go of the wheel and counted to 14 seconds (1,001 1,002 etc) before I had to take hold of the wheel again. When conditions are good, when the highway is built for it, and the vehicle has the appropriate aero mods and is good condition I have no problem with higher speeds then 75 mph. I think aero can allow us to go faster, safer, and more fuel efficient then vehicles without good aero.

100
 

The T-100 felt rock steady at 105-mph on the salt.It had nearly a 50-50 weight distribution and isn't as tall as many contemporary pickups.
She's essentially zero-lift according to the wind tunnel,which validates Goro Tamai's comment about the stability of half-bodies.
And she's very stable in crosswind and gusts.
I suspect Aerostealth's F-150 can shrug off many issues which would plague a garden variety pickup.

My experience driving 100 MPH: "Wait, I am dead?!"

At one time people were terrified at flying along at speeds faster then a horse could run. We now routinely operate our own vehicles at 75 mph so what is so magical about 100 mph. Safety has improved so much that people can and do survive crashes at speed in many accidents. NASCAR expects drivers to survive crashes at double the speeds we drive. With pre 1960 cars people died in low speed accidents.

We were just pointing out that 1: the interstate highways are built for higher speeds 2: if the vehicle has good aero it can be stable at these speeds (80 mph to 105 mph), and that such a vehicle would return much better fuel economy at these higher speeds then current cars and trucks.

If you want to be absolutely safe I would recommend you not drive or ride in motor vehicles at all. I certainly would not ride in any vehicle traveling over 55 mph. After that crashes where you leave the roadway typically involve more than a half million ft lbs of forces which have to be dissipated some way. Science can help us with this, unreasonable fears and a closed mind can not. I for one would like to be able to travel in my personal vehicle at greater speeds between cities reducing travel times. I would never suggest anyone who does not be forced to do so.

[img]s1378.photobucket.com/user/John_Gilkison/media/20150104_113344_resized_2_zps72d02aab.jpg.html]20150104_113344_resized_2_zps72d02aab.jpg Photo by John_Gilkison | Photobucket[/url][/img]

You should have an [img][/img] between the photo fer it to show. ;)

Doesn't show...
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With the [img][/img] tags...image shows. ;)
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Bam zip pow, I appreciate your attempt to help but I have no idea where the [img] should be placed in the url from reading your post? Do I place it myself or do I take steps for it appear automatically. Phil has sent me written instructions on how to post pics from photobucket which I have followed to the letter. I could repost his instructions for you. There is some step that you all consider to be so obvious no one is mentioning but it is not so obvious to me.

A sample would help. The description tells me nothing I can interpute.

If you click on the "Quote" button on my previous post, you should see how the [img][/img] tags are used. Once I git to yer area this weekend, we can go over that as well. ;)

I figured it out. When are you coming through Las Cruces. You should call me soon.

If the Ferd also has 50/50 weight distribution I'd be more inclined to agree with the rest. The high COG and normal "bad" weight distribution plus limited tire contact patch exacerbated by tall sidewalls leads me to believe otherwise. Truck understeer (aggravated into oversteer by getting outside of door placard tire pressures) means the safe window is closed much faster at ordinary speeds (on a truck that is 65 and lower). I run that high speed Interstate all the time and can report I've seen some hairy moments for pickups through the passes.

That said, I believe FE numbers are pretty much meaningless -- just a stunt -- unless it is bracketed by mpg numbers and other numbers from when the truck is loaded to GVWR.

To be taken seriously I don't see how one can do otherwise. Driving under a load calls for changes to driving. And then pulling any kind of trailer yet another subset.

Am enjoying your efforts. Make no mistake. Look forward to more

In the 1930s they would find wrecked cars in the branches of trees. Now that's aerodyamics.

It is what you think you know that ain't so that can be the biggest obstacle to knowledge. I for one have no problems with traveling on the interstate highways at the posted speeds all day long. The truck is very stable at highway speeds, the fuel economy is good with aero and the engine is just loafing. In fact I would maintain that higher speeds put the engine in a more efficient place meaning a little more load.

I understand you believe you have a point to make. And that skill somehow compensates. I agree that better aero helps. But doesn't overcome the deficiencies of a pickup truck. Cars will skid and spin around well above the point where trucks roll over. Which is why the DPS Tahoes are lowered so dramatically. And why the operators have to exert such care at high speeds. (Their words to me). Keeping risk to a minimum is the only avenue worth exploring, long term. All other approaches have a higher cost. Driving skill arguments are a dead end.

Pickup trucks are about payload. It is their reason for being. Towing an especially large load compared to a car is second. They are a failure for passenger transport unless we include vans as to seat mpg.

Questions about payload, axle and tire loads, etc may not be exactly to your vision, but they are nevertheless central to what is a pickup truck. On that, with your truck and with or without your trailer, are the trade offs understood by others to arrive at a more satisfactory average annual mpg. It isn't merely highway versus city (better said as steady state versus stop and go), but working versus empty. How well is it justified if only for fuel expense (becomes the question)?

Empty miles don't pay. The cheaper they are, the better, granted. Things tend to come down to the percent of each. One can read the experiments of others with this known. As with climate and terrain past truck spec. Comparisons. Your mpg appears to be just above mine at 55 and at 65. Today's turbodiesel 1T trucks are grossly overpowered with a stratospheric initial cost and no longer desirable from a mpg standpoint versus work performed. But my comparison is made to yours when my truck is solo and loaded to 87% of gross.

So, how to compare? Would a replacement gasser 1/2T truck with aero aids skew the empty miles high enough for me to warrant the change? Etc. My travel trailer is heavy, but aero. A half ton can do it. But how well becomes the salient point when all miles are considered. A grey area.

I'm not alone in approaching pickups from the standpoint of commercial considerations. It separates the wheat from the chaff. And it isn't meant to be a wet blanket. On the contrary, it -- your truck, solo and towing -- can be powerful evidence of how to make a particular kind of pickup truck work more favorably. Shining a light on the grey areas is what is being asked.

Weights, loads, and steady state mpg as you accumulate miles will be greatly appreciated. And skillful use of a certified Cat Scale is your friend as to reducing road horsepower as you iron things out.

Thanks for your consideration.

My truck with full aero kit and me in it plus about 100 lbs of travel gear weighed 6,360 lbs. The front axle weighed 3,420 lbs. This means 53% of the weight was on the front axle and 47% of the weight was on the rear axle. This hardly qualifies as overly light in the rear or front heavy. A lot of cars do not do this good.

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I had a few people who criticized how my truck looks by comparing it to a Pontiac Aztec. We were at Sam's Club and I happened to park beside one so I took a picture for your edification. There is no way the air can follow the rear end roof slope of the Aztec but it can on my truck. I find it strange that some people are so hung up on looks enough to totally discount performance.

My brothers son is working on putting a 1966 Chevy truck back on the road. They have dropped a 327 Cubic Inch V-8 engine in it and changed the transmission to a 3 speed auto with overdrive. While I applaud the gear changes I just had to ask my brother just how much HP could that engine put out?

He told me 350 HP. I explained to him I had a 213 Cubic Inch V-6 that could put out 365 HP and it was mated to a 6 speed auto. What Rob may not understand about his new wonder truck is that it has a Cd of around 0.5.

On my truck doing 80 mph it takes about 30 HP to overcome rolling resistance and 48 HP total to do 80 mph. The remaining 48-30 = 18 HP is overcoming drag. MY truck naked (Cd=0.402) needs 64 HP to do 80 MPH so it is then requiring 34 HP to overcome drag. In other words my Herndon Aeroshell which reduces the Cd to 0.34 has reduced my HP requirements to do 80 mph to overcome aerodynamic drag by about 48%.

We will have some warm weather data for you all in April when I meet Phil at Monahans SP. I do find it interesting how completely unaware people really are about the real forces that are affecting the mileage in their vehicles.

Ah, lovely Monahans. If an all too large white 579 Pete with all too much power and a bigh aluminum tanker blows you a kiss in passing, you can think on my 4.6-mpg average for that round trip from Corpus Christi.

Agree about the Aerolid. Tried to get a new owner of an EcoDiesel Ram interested. He already has a '69 Chevy smallblock truck for fun. And is proud of his solo and Airstream towing mpg. But, no, looks are too far out. Just think how cool a riveted aluminum bed topper with basic aero lines would look while towing that travel trailer.

I IH10 is better than IH20 for this. Far less traffic and better road surfaces.
There are also some bad stretches between Gillespie County and Fort Stockton as to crosswinds. I'll try and make notes of the longer, better sections per mile markers next time. The final ten miles westbound into Fort Stockton from MM 270 on a downhill, to the 259B exit for Monahans is almost absolutely flat.

Try the high octane coffee there at the Flying J.

You might also consider a CB radio. A roof mounted Larsen NMO 27 or Wilson 5000 antenna, and a Cobra 29 with bigger finals by Clays Radio Shop in San Antonio (X582, at the Petro) with a Roadking 56 mike will get you heard. A Cobra 500 DSP external speaker will aid greatly. You can also mail order something a little nicer from BELLs CB (schottky mods).

I can easily converse 10 miles or better if the other operator has a decent radio out west of JNunction. And hear farther. Which matters if knowing what Joe Law is about at that moment.

Folks have next no idea how useful is a CB. A clean, no noise install using amateur radio guidelines (and covering underside of that Aerolid with McMaster-Carr sourced copper foil, would make a great rig) and it's an altogether different beast than what us oldsters remember from the 1970s.

From Ozona west can be a pretty good concentration of LEO usually working as task forces. Not many smokey reports these days, but you'll usually get an answer as this stretch can feature drivers out at the edge of their legal hours.

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Just installed this cheap wheel cover on my spare. I tried a larger cover yesterday and the air ripped it off in one mile. It is just a test as I need a more durable material then poster board.

You should swap your taillights side to side and turn them upside down. You'd probably only need to cut and swap a square foot of sheet metal to do it.