Converting to LiFePO4 batteries and Sailor Man's LiFePO4 Build

[sailor man]

Well the rear Advent Air conditioning unit is gone and there is a small 14” x 14” hole in the overhead. The old Advent air conditioning unit was 21 1/2” x 22 1/2” x 3 1/2” deep.
There is a nasty discolored patch in the overhead, 21 1/2” x 22 1/2” that looks nasty. I have ordered (2) Jensen 46VR 12v dc lat screen tv units that will lie up flat to the overhead on a 12” x 12” Vespa mount. The TV can drop down and rotate. The entire is 22” x 22 1/2” x 3 1/2”, so it will not take up the entire space.
I plan to fashion a sold cypress panel to match the cabinetry that hides the tv. I might add indirect edge LED lighting to illuminate indirectly illuminate the surrounding overhead and period a couple of adjustable recessed reading lights.
I will do the same thing forward in the salon where the forward air conditioning unit used to be.
And here is the 48v dc YMGI heat pump in the salon.
I think that the curvilinear surface of the YMGI mini split compliments the similar forms of the coach.
View attachment 8630
View attachment 8631
The overhead flat tv and enclosure will be much less bulky, so the and the space will seem much higher and more spacious.
The scissors couch will expand into a double bed and it is across from the dinette that also months into a double bed. I hope that I will be able to rotate both the passenger and driver seat around to make this a very spacious and cozy room.
On top of it all, the heating and air conditioning will be very quiet. In a pinch, I could even turn on the dashboard air conditioning without starting the engine.
I hope it will be a very pleasant and peaceful place, especially if we are boon docking in the wilderness.

On the top picture, you can barely see the 3 circuit dc breaker panel in the location where the former generator switch was located. In the original electrical power center there was a 15 amp dc breaker for the original refrigerator. I took that wire over to this 3 breaker panel to power it. Idel requires a 15 amp breaker for each of their compressors, but that is way overkill for the unit you are installing. I have not been able to get an update from Idel but I suspect that with the greatly reduced electrical power requirements, 5 amp circuit breakers would probably be more appropriate.

 

[sailor man]

I saw a YouTube video recently that a Hyundai sorrento electric fan nearly matches up with the original radiator, that might work for your desired fan setup.

Take a look at posting #244, 2/21/23 on Page 13. This is the fan cooling system that is described by Jason Stryker in the GMC COOP video on how this system works. It is the one that I having installed.

 

[sailor man]

View attachment 8738
Jason Stryker delivers the Drew Koba COOP 455 and the motor meets the coach.

JasonStryker

Now that the Drew Koba 455 is in my coach, I am left with the old 455 that was running just fine on the motor stand that I bought. I don't know what to do with this engine, so I called Jim Bounds and asked him if he would build a new COOP from it. He said that he would love to, so is there anyone interested?
I paid $8,000 for the new engine just as you see it here. I did not have to buy a crate 455 plus shipping. I didn't think there would ever be another built like it so I put in a bid at the COOP auction and won it.
The GMC COOP had options for serpentine belt systems, FiTech fuel injection and other upgrades for additional costs.

Jim Bounds says that no one else has made a COOP 455 arranged like mine.

My set up is very different. The March Racing components came with a new power steering pump and water pump. I am happy with that because so much of the new set up is brand new and I hope will be far more reliable.
I think that the head was replaced about 20 years ago.
I just hate the thought of just junking this engine. I can't stand throwing out useful stuff. Help me out!
Oh, Jim says that Chuck Botts is gone. However, I found something very interesting that he investigated. He installed a HHO system on his COOP 455 and tested it. He says that he increased his fuel efficiency from 8.0 mpg to 11.5 mpg. Does anyone know about this system?
Here is the link to his presentation:

https://doc-10-bk-apps-viewer.googleusercontent.com/viewer/secure/pdf/3nb9bdfcv3e2h2k1cmql0ee9cvc5lole/hsvneeuu3t1ubiq6rv7lr38ht19omog9/1711189425000/lantern/*/ACFrOgBVbtO-RIF6zKIAOJRz8BPJhpmkuhR8dTsG2EnT36XPkrPYJfQpptEefnvRlx-KtoNwYr9-rvfIvn8nedogKo6YTt-jZMZzWABxxeL8UL9h92E-snM4gb3vrx0INOqgSqACC3f1GTnYGxMu?print=true&nonce=1ka2oihskscag&user=*&hash=mntpkgsdvpu9l122t97hklkovl3uo7eu

Anybody know anything about this?

I already buy lots of distilled water because I use it in my CPAP machine to control my sleep apnea. I got tired of carrying around cartons of 6 jugs of distilled water, so I just bought a small device that makes distilled water from tap water. I wonder if I can make my own fuel.

I will be posting later my solution for collecting rain water to eliminating filling my water tank with municipal drinking water.

Just think, rain water is close to distilled already. If I collect it before it hits the ground, I make distilled water from rain water. I then turn distilled water into HHO (hydrogen & oxygen) using the solar electrical power I am collecting and mixing it with bought ethanol free gasoline. Won't that be cool!

Maybe this is better than than installing electrical motors to replace the internal combustion engines.

 

[LarryW]

The link to the presentation is damage and not working. Try again copy/pasting it and see if it works for you before you repost it. Interesting concept.

 

[RF_Burns]

Here is a discussion thread on HHO archived from GMCNet in 2015 started by Charles Botts.

Saving $1.00/mile with my HHO hybrid system

When gas is $3.47/gallon, I have saved $1.00/mile with my HHO hybrid system that has a patented PWM digital controller by adicorp.net http://adicorp.net/ . The systems ROI is less than 1400 miles. Everything is available over the net. The system can be viewed on gmcws.org/blog/?p=3340...

www.gmcmotorhome.org

The link in his initial post to the source of his PWM controller is no longer available as is the link to his book on the subject.

This link to his presentation to GMC Western States is still available. (for some reason I must click on the title of the document to get the actual presentation even though it shows the same URL)

Saving $1.00/mile with my HHO hybrid system

When gas is $3.47/gallon, I have saved $1.00/mile with my HHO hybrid system that has a patented PWM digital controller by adicorp.net http://adicorp.net/ . The systems ROI is less than 1400 miles. Everything is available over the net. The system can be viewed on gmcws.org/blog/?p=3340...

www.gmcmotorhome.org

Note that his initial math was wrong (at saving $1.00/mile) which was pointed out to him in this thread. Chuck acknowledged this and corrected the presentation as noted in his document title, although I did not read the document.

 

[sailor man]

The link to the presentation is damage and not working. Try again copy/pasting it and see if it works for you before you repost it. Interesting concept.

Chuck_Botts_HHO.pdf

I also found this that recently received an award in Europe.

HHO Kit HS 4000 Pro

Hydrogen Generator - Save fuel up to 30% Reduce emissions by 78% with a Hydrogen Generator. Get the latest HHO technology now!

www.hydroxsystems.com

 

[Kendra]

Now that the Drew Koba 455 is in my coach, I am left with the old 455 that was running just fine on the motor stand that I bought. I don't know what to do with this engine, so I called Jim Bounds and asked him if he would build a new COOP from it. He said that he would love to, so is there anyone interested?

Distance too far for me (opposite corner of country) but someone in the region‘s gotta want this built to spec or an as-is spare. GMCMI classifieds currently lists a 403 near Boston and a 455 north of Denver.

 

[RickHaugh]

One must consider the actual conditions, trying to match the actual demand for energy with actual solar radiation.
I am located in Florida, which means that I am closer to the equator than most of you. It is true that June 21 has the maximum solar radiation, but that does not match the time for maximum demand. Generally, air conditioning loads are maximized in the 6 weeks in August and September here. That is also true in other locations. It takes a long time to heat the Earth's mass. This is a delaying flywheel effect.
So as one approaches the autumn equinox, one faces the greatest cooling demand.
In Florida, it is spring when we collect the most solar radiation. It is the dry season with little moisture suspended in the air. In summer, it is sunny almost every day until about 4:00pm EDT here (Solar Time 2:00) and then the clouds and thunderstorms start. Tampa Bay is actually west of Detroit, so we are in the wrong time zone.
What seems to be never talked about is how to control demand. Air conditioning needs to be controlled by temperature and humidity. It is almost universally controller only by temperature.
Lowering the humidity in controlled air allows much higher air temperature and sensible load is directly related to the delta temperature between interior air and exterior

Who would have guessed…
Detroit is west of Tampa.
Detroit (United States): 42.33143, -83.04575

Tampa, FL : 27.964157, -82.452606.​

 

[eserv]

Chuck_Botts_HHO.pdf

I also found this that recently received an award in Europe.

HHO Kit HS 4000 Pro

Hydrogen Generator - Save fuel up to 30% Reduce emissions by 78% with a Hydrogen Generator. Get the latest HHO technology now!

www.hydroxsystems.com

 

[sailor man]

Distance too far for me (opposite corner of country) but someone in the region‘s gotta want this built to spec or an as-is spare. GMCMI classifieds currently lists a 403 near Boston and a 455 north of Denver.

I talked to Jim Bounds about my old engine and asked him if he was interested in making a new Koba Olds 455 COOP engine out of it. He is interested in doing it. I just can't throw it away or wait for someone to ask for it. Maybe we could have Cliff add another of my March Racing serpentine belt system.
Maybe my GMC Coop 455 will not be the last after all.

 

[eserv]

No water heater boondocking and I haven't tried the furnace this way (I will this year).
- 3 roof vent fans running 24/7
- Propane fridge 24/7 (also consumes DC power)
- 3 additional USB fans running all night
- Lighting as needed, and charged phones & iPad
- Swamp cooler 4 to 6 hours per day.
Swamp cooler fits over the engine cover and draws shaded air from underneath while parked, uses an electric car radiator fan plus a 12v pump to mist water (helps in Nevada but not Florida).

I'm about to switch from propane fridge to a dedicated 12v DC fridge. I'll do a full write-up this spring along with amperages.

Apologies to Sailor Man, I don't want to hijack your build thread. Hoping this information helps with decisions.

Tell me more about your swamp cooler! I need something to cool my rig without using much electricity. I'm in western Canada so the air is pretty dry here and I doubt I'll ever go where the humidity would be too high.

 

[Kendra]

Tell me more about your swamp cooler! I need something to cool my rig without using much electricity. I'm in western Canada so the air is pretty dry here and I doubt I'll ever go where the humidity would be too high.

The swamp cooler I designed is grafted onto the engine cover when parked. This was done at the same time we converted to solar (half dozen Renogy flex panels, 300A LiFePo, Victron inverter etc.) and eliminated the generator. The swamp cooler did the job while parked 1-1/2 weeks in the Nevada desert a loooong way from the nearest shore power. Didn't start the engine until we left and we were able to run everything except A/C.

I think one reason this design works is it draws air from under the GMC while parked. I figured the air under the engine (once it's parked a few hours) is a few degrees cooler since that's shaded by the GMC at all hours. It worked.

Details on the swamp cooler that snaps onto the engine cover are in the thread GMC at Burning Man 2022.

 

[eserv]

The swamp cooler I designed is grafted onto the engine cover when parked. This was done at the same time we converted to solar (half dozen Renogy flex panels, 300A LiFePo, Victron inverter etc.) and eliminated the generator. The swamp cooler did the job while parked 1-1/2 weeks in the Nevada desert a loooong way from the nearest shore power. Didn't start the engine until we left and we were able to run everything except A/C.

I think one reason this design works is it draws air from under the GMC while parked. I figured the air under the engine (once it's parked a few hours) is a few degrees cooler since that's shaded by the GMC at all hours. It worked.

Details on the swamp cooler that snaps onto the engine cover are in the thread GMC at Burning Man 2022.

Not a lot of details there, though I guess I can figure out what you have done from the photos. I have 300 watts solar installed with 200 ah LFP battery. A mixture of Renogy and Victron components! Also a 2500w pure sine inverter but I still have the generator. (for now) I'll try it out this summer and see if I need the genny at all. I think with an evaporative cooler I can eliminate the roof air and generator reducing the weight and wind resistance for more efficiency. I don't think any long distance trips are in my future so likely always will be in relatively dry Western Canada.

 

[sailor man]

I have come across a paper published in the Alexandria Engineering Journal, Alexandria, Egypt, Circa 11/21/2015 that seems to confirm Chuck's experience in using HHO in his coach.

https://pdf.sciencedirectassets.com/270704/1-s2.0-S1110016816X00026/1-s2.0-S1110016815001714/main.pdf?X-Amz-Security-Token=IQoJb3JpZ2luX2VjECcaCXVzLWVhc3QtMSJHMEUCIQCmM6%2F3ZGhFuhcMmDzO5BSv2sEtuVGQbrkYcDrs6jjMPQIgNwN45eB0VzgGbzp30695%2FVgK%2BGP%2B8jkIlBlk17KgZz0qswUIYBAFGgwwNTkwMDM1NDY4NjUiDKHmJrn8Fc%2B%2Fqe9lNyqQBdZuTSj%2Fmq0zSszqEdQe33DyYrFugd9IasIru9USBG291nwAivPV7whJwF%2FByywq1colJHWf30zvuaVG5AAsAGr1DDHJw1w41AZb4ZsRzaZk9WoVhhOcELjo%2BPYJDXaWoYnpkpkYCb6X1xe6tzGnzVTeneAYfit8Dat0a773m%2ByoGf%2FMriXzhCNwsR40JT7VziSNQBrAXc%2Bzy5yYqaXXSkoOPnvkMb%2FgJRbc2S6tpF97ptsiSxXCX%2FOwo7telliHvTIT0l4FXvpJwdhqDuH0h7vRyt6I0PGJPV1wRtYc6Q6XWBd8AUFN6j3ZWAfw3w8uIoOWKo%2FcGqIF1ysv5es2uJs8DfBWsdlyfPAEuZyvZoG0Dlt%2Fj1nYojzPmSd9BpXcw0HwaRYasb3MwA%2BvDLxV2wptbJyDScQq9LVTOKHrxsNyGHIx78KZ9ysrE1YcZ551X0ZfM4KtIDD2fu4NqT9R5Q45Pfyp7YohYdX2gLwQewBNiqu3PYXOB0rFAuhww4W%2Fujp7s4vg0M1c2AyVB5SWXKIGhTcYXeThB0xP99SLKaBIOMY9imKR%2Bb7EnWM11CS8%2FvHOImafTEdo95DmYovXn2%2FckpTp84ZOsy4gETlPJ6kbI55iw8zX029mSIWd29yE4spMEK1msOcAhOEWnqGV6eNaYgVMJk9AAMRqJnSvWm5QXzKVdFzyutXeLkiB%2BCZfA2nu6CVSb7IxRBvTuFcDw%2F5H9kZF4ONFAGwjIaN9ktZkkQeh73pMqXIn9qh%2FIb%2BJDgqw6qNdzuQ7A5xF2FRjPGh7uS5wXH2qngxwYtEdTkDKrt2mkAm6iYvV7Rd%2Bvn624QyJa5t25xVvRmLiPMfkv27bj2AjUdm%2FF%2Bqbu3vCUun9MOKI5bAGOrEBw%2B2%2FA6mKaH%2FykyOvYVzcV84hLUaaz2YZqtnjEiZPe8X7bBZWfhLwDVz5OZVR9mPo8Z5UOI6YfA5NLjOnyrNfGCUBHxpOp%2B44xp60MwbcWPIj8uJSedclazQhCeba%2B4VJtCEWxn9H0prBIz7jBTtQhXqhjewa4EU2OUKoFJxsYUdJK5HIM5UQj%2FX8EswGxXL9jD0VDACuEpBdlh1dTHQPFTkicdRR8mOWNNpNTWZGwEnv&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Date=20240412T161815Z&X-Amz-SignedHeaders=host&X-Amz-Expires=300&X-Amz-Credential=ASIAQ3PHCVTYUQHZMR63%2F20240412%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Signature=af8208b9d8bf54b2145733543553a4e2d90ca788fca71327d31b60ed2eb173b8&hash=102193b8c608f750e1c15d4c45a409ded8f542bcfbb115bf38d2c5c739403d10&host=68042c943591013ac2b2430a89b270f6af2c76d8dfd086a07176afe7c76c2c61&pii=S1110016815001714&tid=spdf-24a28017-35c0-45ba-8333-691b82bb3d4c&sid=60cff1377f7c4549ff89875977980bbf2332gxrqa&type=client&tsoh=d3d3LnNjaWVuY2VkaXJlY3QuY29t&ua=1517595756505a52&rr=873487fd0ad96d9e&cc=us

I hope that this link works!
The conclusion states that HHO increases the thermal efficiency by 10% resulting in a 34% reduction in fuel consumption. That is what Chuck Botts said. It also showed an 18% reduction in CO, 14% in HC and 15% in NO.
The link worked, so let me know if you have problems.

 

[boybach]

I have come across a paper published in the Alexandria Engineering Journal, Alexandria, Egypt, Circa 11/21/2015 that seems to confirm Chuck's experience in using HHO in his coach.

https://pdf.sciencedirectassets.com/270704/1-s2.0-S1110016816X00026/1-s2.0-S1110016815001714/main.pdf?X-Amz-Security-Token=IQoJb3JpZ2luX2VjECcaCXVzLWVhc3QtMSJHMEUCIQCmM6%2F3ZGhFuhcMmDzO5BSv2sEtuVGQbrkYcDrs6jjMPQIgNwN45eB0VzgGbzp30695%2FVgK%2BGP%2B8jkIlBlk17KgZz0qswUIYBAFGgwwNTkwMDM1NDY4NjUiDKHmJrn8Fc%2B%2Fqe9lNyqQBdZuTSj%2Fmq0zSszqEdQe33DyYrFugd9IasIru9USBG291nwAivPV7whJwF%2FByywq1colJHWf30zvuaVG5AAsAGr1DDHJw1w41AZb4ZsRzaZk9WoVhhOcELjo%2BPYJDXaWoYnpkpkYCb6X1xe6tzGnzVTeneAYfit8Dat0a773m%2ByoGf%2FMriXzhCNwsR40JT7VziSNQBrAXc%2Bzy5yYqaXXSkoOPnvkMb%2FgJRbc2S6tpF97ptsiSxXCX%2FOwo7telliHvTIT0l4FXvpJwdhqDuH0h7vRyt6I0PGJPV1wRtYc6Q6XWBd8AUFN6j3ZWAfw3w8uIoOWKo%2FcGqIF1ysv5es2uJs8DfBWsdlyfPAEuZyvZoG0Dlt%2Fj1nYojzPmSd9BpXcw0HwaRYasb3MwA%2BvDLxV2wptbJyDScQq9LVTOKHrxsNyGHIx78KZ9ysrE1YcZ551X0ZfM4KtIDD2fu4NqT9R5Q45Pfyp7YohYdX2gLwQewBNiqu3PYXOB0rFAuhww4W%2Fujp7s4vg0M1c2AyVB5SWXKIGhTcYXeThB0xP99SLKaBIOMY9imKR%2Bb7EnWM11CS8%2FvHOImafTEdo95DmYovXn2%2FckpTp84ZOsy4gETlPJ6kbI55iw8zX029mSIWd29yE4spMEK1msOcAhOEWnqGV6eNaYgVMJk9AAMRqJnSvWm5QXzKVdFzyutXeLkiB%2BCZfA2nu6CVSb7IxRBvTuFcDw%2F5H9kZF4ONFAGwjIaN9ktZkkQeh73pMqXIn9qh%2FIb%2BJDgqw6qNdzuQ7A5xF2FRjPGh7uS5wXH2qngxwYtEdTkDKrt2mkAm6iYvV7Rd%2Bvn624QyJa5t25xVvRmLiPMfkv27bj2AjUdm%2FF%2Bqbu3vCUun9MOKI5bAGOrEBw%2B2%2FA6mKaH%2FykyOvYVzcV84hLUaaz2YZqtnjEiZPe8X7bBZWfhLwDVz5OZVR9mPo8Z5UOI6YfA5NLjOnyrNfGCUBHxpOp%2B44xp60MwbcWPIj8uJSedclazQhCeba%2B4VJtCEWxn9H0prBIz7jBTtQhXqhjewa4EU2OUKoFJxsYUdJK5HIM5UQj%2FX8EswGxXL9jD0VDACuEpBdlh1dTHQPFTkicdRR8mOWNNpNTWZGwEnv&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Date=20240412T161815Z&X-Amz-SignedHeaders=host&X-Amz-Expires=300&X-Amz-Credential=ASIAQ3PHCVTYUQHZMR63%2F20240412%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Signature=af8208b9d8bf54b2145733543553a4e2d90ca788fca71327d31b60ed2eb173b8&hash=102193b8c608f750e1c15d4c45a409ded8f542bcfbb115bf38d2c5c739403d10&host=68042c943591013ac2b2430a89b270f6af2c76d8dfd086a07176afe7c76c2c61&pii=S1110016815001714&tid=spdf-24a28017-35c0-45ba-8333-691b82bb3d4c&sid=60cff1377f7c4549ff89875977980bbf2332gxrqa&type=client&tsoh=d3d3LnNjaWVuY2VkaXJlY3QuY29t&ua=1517595756505a52&rr=873487fd0ad96d9e&cc=us

I hope that this link works!
The conclusion states that HHO increases the thermal efficiency by 10% resulting in a 34% reduction in fuel consumption. That is what Chuck Botts said. It also showed an 18% reduction in CO, 14% in HC and 15% in NO.
The link worked, so let me know if you have problems.

yes the link works, but it's only really necessary to clip the first part of a link, like so:

https://www.sciencedirect.com/science/article/pii/S1110016815001714

 

[sailor man]

View attachment 10458
Well, what would my 1976 GMC Eleganza II look like when the solar installation was completed. I was beginning to loose patience, so I bought a damaged Hess Training Van model to mock it up.
I could not put the full size SunPower 110w units in some places because of the various vents that I could not get rid of.
It is a good thing that I have already bought the SunPower panels. There is scuttlebutt that SUnPower may have to go out of business because of the dumping of Chinese panels. Almost all of the semi-flexible solar panels use their very efficient Maxxon solar cals.
I think that it will look very cool and not catch the wind.

Well it has been a very difficult 10 months medically, but I am back. I have started to post for the last few weeks, but not on this thread. Please check out the other posts I have been sending.
This is the new Automodello GMC Motorhome model that I have altered to look more like what my coach will finally look like.
It is good to be back.

 

[sailor man]

This is a rather long term project that I plan to undertake after I get the coach back to Palmetto, FL.
The existing awning is not a Zip Dee and is aged. According to the previous owner, one of the studs broke and he fashioned a repair. I have no idea how old it is, so it is probably overdue for replacement.
Since there is 1.47kw of solar panels due to be installed along with the massive on board LiPO4 28.68 kWh, can I do any better?
How about installing (2) new Zip Dee Relax 12v dc awning, almost full length on both sides and instead of using the normal slope, which is almost level, suppose they are tilted up. I found an awning fabric that reflects 71% of the and is yet translucent enough to provide light underneath.
When I mentioned using the 5V galvanized aluminum roofing surfaces on the roof of my house to reflect additional solar energy onto the roof mounted solar panels, the 5V roofing was LEED certified to reflect 2/3 (66.6%) of solar energy. This fabric is supposed to reflect 71%. Not bad for an awning!
In addition, there is now a massive shaded area.
I am considering of how to fashion an easy and rapid take down for sustained and/or sudden winds and downpour.
View attachment 8636
How about this design? I will have to adapt the Zip Dee to allow it to tilt up, rather than down and get Zip Dee to approve this design and use a fabric like the Serge Ferrari. I might have to provide them the fabric. This fabric is a well tested and used awning fabric..
The area of the defective surface is much greater than the area of the solar panels, so there is a chance to achieve a two or three times greater collection of solar energy.
I know that this is really very far out but I would really like to hear everyone's comments, even those that are negative. Earlier in this conversation I mentioned the design for using the reflective surfaces of my house to collect additional solar energy. I also mentioned the possibility of using my coach to forgo using roof mounted solar panels for the house and use my coach instead.
With the three 12v winches, I could probably adjust the angles of the awnings.
Using the coach's air suspension, we could probably play with the tie down tension by raising or lowering the coach.
There are plenty of awning tie down systems commercially available.
Wouldn't it be great to use our coaches in such a fashion!
Anybody want to work with me on this?

This gives you a better idea of how the awnings can work as reflectors for the solar array.

 

[sailor man]

I would like to talk about what I am trying to accomplish by stripping as much as possible to reduce the air drag on my GMC Eleganza II coach.
Just how slippery was the initial GMC motorhome? According to GMC, the wind tunnel test was performed by an independent wind tunnel, not their own. What do these actually use in the wind tunnel and how was it configured?
The reported Air Drag of the test was 0.31. How does that stack up against the competition?
Well as one means of comparison, my front wheel drive 1989 Ford Taurus SHO had a measured air drag of 0.32 and that was pretty good.
If this is accurate, How did they reduce the air drag to that of a pretty decent 4 door sedan?
They made a test model and lucky they made about 8 additional copies of the model for some of the engineers that worked on the GMC motorhome as a retirement gift.
I was fortunate to find a photograph of one given to John G. Locklin and here is a photograph of it!
View attachment 10397
So how close am it getting to the test model?

My roof is almost as clean as this model with the following exceptions:

Pros: Cons
Front & rear bumper covers ZipDee awning on both sides
Bogie cover between read tires Sun shade over windshield
Air dam under front bumper Exterior side mirrors
(15) SunPower semi-flexible solar panels & wire
(pretty flat to the roof with no supporting frame)
Low resistance refrigerator streamline vent
Hopefully out of air stream
HVAC Mini-split heat pump
& Continental tire over rear over rear bumper

Hopefully, this is enough to get my coach very close to the listed 0.31 air drag.
Just how significant is the air drag ratio to how many miles per gal efficiency.

View attachment 10398
I have attached a chart called “GMC Aerodynamic Drag” that I found in the GMCWS technical seminar of 10/10/2006. This data was published by General Motors for a standard 26 feet Motorhome.

Speed Torque HP
40 40 15
55 100 50
70 180 100
80 290 145

When there are storage boxes, skylights, vents, air conditioners, antennas, railings, ladders, rigid solar panels/frames and all kinds of roof mounted items cause a very severe negative impact on the miles per gallon efficiency.
The charts states, “Power to overcome drag grows by the cube of the speed
2 times the speed = 8 x Power
The best payback is to get a much stuff off the roof as possible!

Well, I think that I am getting pretty close to the model that was tested. This is the morning after my coach was towed to my house in Palmetto, FL from Cliff Goldby's shop.
Pretty low air drag and ready for solar panels.

 

[sailor man]

View attachment 4830
When the spare tire is lowered to the ground for either parking or tire replacement, both YMGI mini splits can be used. For changing a tire, remove the lugs while the tire is on the ground and mount the flat tire in its place. There is no lifting of the spare.

If the KiPO4 battereis need help, pull out the lpg powered generator and augment the battereis to maintain the use of the two YMGI 48v mini splits. Since the dashboard air conditioner has been modified to run on 12v dc power, not engine power, all three of the units can be used when parked.

Well, almost everything is finally in place on the rear of the coach.

I need to put on the license plate and fashion a yellow painted board with a large GMC on it to hide the Thule.

Lots of road clearance and easy to get to everything. No more on the roof.


It just extends the belt line, doesn't it. What do you think about this arrangement? It is just as I drew it.
It looks so long, low and sleek.

 

[Kendra]

That clean roofline is inspiring. I rarely use my rooftop pod and it's just about shot. I've never used the rooftop A/C (western US and almost always off-grid). After seeing these photos, I think I'll delete most items off my roof this year. I'm running a DC fridge and no propane water heater, so I'll probably also remove the fridge roof vent.

Less wind drag, noise, and shadows across the solar panels.