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Old 07-16-2017, 07:09 PM   #41
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That's an interesting perspective. My second AC would replace one of the vent fans. I was thinking the bedroom one, thus my comment. In my trailer, the doors between the living area and the head block the flow of air from the single AC to the rear bedroom. My plan was to replace the rear vent fan with the second AC, thus my comment.

Here's a picture of my trailer. Unfortunately you can't see the axles, but they are between the refrigerator vent and the bathroom vent which you can see in the picture. The bedroom vent fan is out of the picture to the right.

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On my trailer, I think the second AC would reduce the tongue weight. On yours perhaps minimally, but it probably wouldn't increase the tongue weight.

Al
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Old 07-16-2017, 07:50 PM   #42
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I don't think there is any downside I'm happy to have 2 ACs especially with the ducted system.
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Old 07-16-2017, 07:52 PM   #43
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How could the addition of anything to a trailer a couple feet behind the ball NOT increase toungue weight?
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Old 07-16-2017, 08:19 PM   #44
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Quote:
Originally Posted by Al and Missy View Post
That's an interesting perspective. My second AC would replace one of the vent fans. I was thinking the bedroom one, thus my comment. In my trailer, the doors between the living area and the head block the flow of air from the single AC to the rear bedroom. My plan was to replace the rear vent fan with the second AC, thus my comment.

Here's a picture of my trailer. Unfortunately you can't see the axles, but they are between the refrigerator vent and the bathroom vent which you can see in the picture. The bedroom vent fan is out of the picture to the right.

Attachment 289660

On my trailer, I think the second AC would reduce the tongue weight. On yours perhaps minimally, but it probably wouldn't increase the tongue weight.

Al
The OP has a 27FB (i.e. front bedroom). In that layout, the 2nd A/C replaces the fan over the bedroom, at the front of the trailer. This will most definitely increase tongue weight. Though likely minimally (~50lbs) as the unit weighs ~100lbs which is shared between the tongue and trailer axles.

This is in contrast to you 30' AS, which is rear bedroom I assume.
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Old 07-16-2017, 08:56 PM   #45
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Quote:
Originally Posted by BillF95 View Post
How could the addition of anything to a trailer a couple feet behind the ball NOT increase toungue weight?


If overall tongue weight is still in the 10-15% range of trailer weight then all is good It may reduce tongue weight a little bit, but in the big scheme of things all is good - especially given the fact that airstream is notorious at publishing lower than actual tongue weights.....
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Old 07-16-2017, 09:11 PM   #46
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Thanks for the response, but my question wasn't if things would be "all good" or anything other than the DIRECTION of weight change (more or less). Al and Missy corrected my statement that a second AC on a 27FB would INCREASE tongue weight and instead said it would DECREASE the tongue weight. I still don't understand how that is possible or if that correction was accurate?

How is it physically possible to add weight in front of the axle and decrease toungue weight? I would love to learn that secret!
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Old 07-16-2017, 09:15 PM   #47
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How is it physically possible to add weight in front of the axle and decrease toungue weight?
Mathematically (and hence physically) it is not possible.
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Old 07-16-2017, 09:21 PM   #48
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Quote:
Originally Posted by pteck View Post
The OP has a 27FB (i.e. front bedroom). In that layout, the 2nd A/C replaces the fan over the bedroom, at the front of the trailer. This will most definitely increase tongue weight. Though likely minimally (~50lbs) as the unit weighs ~100lbs which is shared between the tongue and trailer axles.
This is the correct answer.
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Old 07-16-2017, 09:31 PM   #49
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Well I should revise my answer I suppose. there would be a proportional distribution of mass for an increase of X units of weight that is placed Y distance aft of the axles with a trailer that has a length of Z for a given fixed position of the axles. Weight on the tongue is not 1:1 increased by weight that is aft of the axles, it would be increased proportionally, which could be a value >= 0 or it could be a value < 0.

If you stack a pallet of bricks on the rear bumper of a 25' airstream the tongue weight would be increased proportionally by, well, a negative factor.

So for the purpose of this discussion I suppose the correct answer is "it depends".
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Old 07-16-2017, 10:15 PM   #50
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Quote:
Originally Posted by pteck View Post
The OP has a 27FB (i.e. front bedroom). In that layout, the 2nd A/C replaces the fan over the bedroom, at the front of the trailer. This will most definitely increase tongue weight. Though likely minimally (~50lbs) as the unit weighs ~100lbs which is shared between the tongue and trailer axles.

This is in contrast to you 30' AS, which is rear bedroom I assume.
I totally missed that the OP's trailer was FB. My apologies - addition of an AC in the front vent fan location would obviously (except to me, apparently) increase the tongue weight. Sorry for the confusion.

Al
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Old 07-22-2017, 10:12 PM   #51
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I am semi-huddled in my 25 FB, with the exterior temp at 104 F for the fourth day. Never before have I even considered adding a 2nd unit but today... whew, it would be neat. I am on a full sun campsite which I'd have never chosen if anything else was available. And winds and passing storms havent made the area awning friendly either.

In spite of all that I still dont want an AC that I would only use 4 to 6 weeks a year. A portable that I could pop in my front window frame with a piece of plywood to fit it snugly in the frame and a heavy extension cord to the 20 amp outlet? Almost went shopping for that today.

Remembered but did NOT build the "redneck A/C" - a drywall bucket 3/4 full of ice with 2 or 3 holes drilled in the sides to fit short lengths of dryer exhaust hose, and a round fan facing down on the lid - which has the center cut to fit the fan. The thing actually works pretty well, even when you're outside under the awning.

Anyway as a full timer the last solution is the most weight and space effective... and cheap too.

Ah mountains, autumn or camping in the far North.....

Paula
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Old 07-23-2017, 09:33 AM   #52
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No changes to my posts of five years ago, except to amplify:

Granted I would use a second AC longer than 4-6/weeks (I am also w/o shade at present and winds are such to keep awning use at a minimum) it's also the option of only cooling part of my 35' that attracts; the redundancy of two AC in event of failure (I've replaced three in last five years on two trailers); it is also that I can rapidly cool the interior after being away without having to leave for most of the evening; I'd have choices about sound levels with an AC at either end; with one unit on Fan only and the other on Cool also speed/maintain comfort; with two Heat elements can much more effectively take the edge off of a chill morning; etc.

That it might be a six week window wouldn't change that for me. I still use the same now ten year old dehumidifier to lighten the load on the 15k unit.

I believe it also is more attractive to a buyer as well to two roof units. I may not ever sell, but I believe it "best practice" to maintain or modify accordingly.

.
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Old 07-23-2017, 09:44 AM   #53
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After mulling over this, I've decided that I'm going to try the approach of upgrading my single penguin 1 13.5k to a new generation blizzard next 15k heatpump. The 13.5k is marginal in my 27fb. I think the higher capacity 15k, but also better efficiency and higher airflow of the new blizzard should make it adequate.

This way I can keep the fantastic fan in the bedroom which is much more used. But also keep the 30amp electric system and not complicate it.
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Old 07-23-2017, 11:08 AM   #54
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Quote:
Originally Posted by BillF95 View Post
How could the addition of anything to a trailer a couple feet behind the ball NOT increase toungue weight?
Because the axle is the fulcrum, in this case, so any weight added behind the axle reduces the tongue weight.

Quote:
Originally Posted by Foiled Again View Post
Remembered but did NOT build the "redneck A/C"
I recall seeing a guy who had a garden hose from his house to a car radiator inside with an electric fan blowing on it. A second hose went out to a sprinkler head so the outflow went to water his lawn.
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