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Old 02-07-2011, 09:17 PM   #15
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3 Point Level


Lew:
If the operator understands what is needed, the 3 point works great. As long as the unit can pivot on the front pivot point, there will be no twist on the unit. see my post here. The key is to understand what you are doing.
http://www.airforums.com/forums/f313...der-70332.html

On a lighter frame I agree that there is more chance of damage if done wrong.
Dave

Quote:
Originally Posted by lewster View Post
There is only one company that manufactures a MADE IN AMERICA, fully self-contained, ready to install hydraulic leveling system for RVs. That company is HWH, Inc. of Moscow, IA, where they design and fabricate almost 100% of their products; including their own steel and electronics!
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Originally Posted by lewster View Post

Their systems are available in either manual or automatic models for self-leveling and ALL of their systems use their patented 'bi-axis' leveling system which uses jacks in pairs so as to totally avoid any frame flex or twist. I have seen 3-jack systems pop windshields and break wall/roof seams open on large motor homes from frame twist. HWH 4-piston systems NEVER do this...they just level your RV!

If you're not familiar with these systems, you should check out their web site. And please don't tell me that they are expensive..........YOU GET WHAT YOU PAY FOR!

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Old 02-07-2011, 09:58 PM   #16
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Dave,

Unfortunately, I have experienced frame flex in my own Monaco Dynasty with 3-point jacks, as have clients of mine. Damage has resulted even though they have followed the very specific instructions TO THE LETTER regarding the operation of their 3-point leveling systems. These were made either by KVA or Power Gear.

In my experience, no HWH system has ever experienced a flex problem due to the pairing of the jacks that raise either the entire front/rear/or side jacks in pairs completely, thus eliminating any possibility of damaging frame or chassis flex.
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Old 02-07-2011, 11:12 PM   #17
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Quote:
Originally Posted by lewster View Post
Dave,

Unfortunately, I have experienced frame flex in my own Monaco Dynasty with 3-point jacks, as have clients of mine. Damage has resulted even though they have followed the very specific instructions TO THE LETTER regarding the operation of their 3-point leveling systems. These were made either by KVA or Power Gear.

In my experience, no HWH system has ever experienced a flex problem due to the pairing of the jacks that raise either the entire front/rear/or side jacks in pairs completely, thus eliminating any possibility of damaging frame or chassis flex.
Lew I'm not doubting you but I am curious how this might happen. The only scenario I can imagine is that too much rear leveling with not enough lift on the front jack therefore driving one front corner into the ground.

By the way I do have an older manual HWH system that is controlled by 4 independent valve levers. Unless you operate 2 levers together the jacks will operate one at a time.

Like others I would recommend boatdoc incorporate a 3 point system unless he can come up with some kind of electronically controlled system. Operating a hydraulic cylinder with a n/c solenoid is not really that smooth unless you can incorporate some proportioning to the valve,

Good luck, Dan
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Old 02-08-2011, 05:53 AM   #18
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Originally Posted by NevadaGeo View Post
Totally confused here. My Excella says to only lift the trailer at the jacking points, clearly marked on the frame behind the rear axle. Only. The other 4 jack type things are to be used just for "stabilizing" so the trailer don' be rockin'... Are you suggesting to us newbies it's okay to put a hydrulic jack anywhere on our trailer and raisethe trailer off the ground anywhere? Or is there a motorhome response in there. Please clarify.
Hi NevadaGeo, crusier54 and Lewster;
Thanks Lewster for clarifying the difference in frames. Despite my diagonal bracing built into cross members my frame will twist anyway if jacked up improperly. There is no way to build a 6" deep frame of 24' of length and 5' width which would not twist. This I am aware of. Regardless of the strength of my frame, the idea which I intend to incorporate is unique.

I am familiar with Motor Coach jacks. They are massive in bulk and length. I do not have 2' of clearance and I cannot have 2' of the jacks coming through my floor on the inside. What I have is a 6" belly pan space. At the same time I would hesitate to spend lot of cash on a integrated system which would turn out to be unusable to me. If you buy it you own it, like it or not. My point was to build a 6" overall length pistons with 4" stroke. We have machined four single acting pistons cylinders out of aircraft grade aluminum in 6" overall length. Bore is 1.5" with 4" stroke. SS piston rods with caps were salvaged from Evinrude "Fast Track" power trim unit from a outboard motor. In retracted position the overall length of the cylinder is 6". This length will permit installation of the pistons in vertical position inside the belly pan with only 3/4" hole in the belly pan skin for the piston pin to come through. To spread the weight on the frame evenly I will mount them 7' forward and aft from the center of the frame. But the problem I am having is finding a hydraulic pump with 1800 Psi capability which would pump no more than 10 Cubic Inches of fluid per/min. This would offer me ample time to respond while controlling it with a joystick. Even if the pump did not incorporate a pressure relief valve one can be integrated. Double acting pumps are not applicable for me because I do not want to have double number of hose and solenoids. If I must, I will use the New Generation Bennett pump at $1100.00 for which I was trying to avoid spending for this experiment.

The 4" of piston stroke will be more than ample to level the trailer where initial leveling can be done with spacer ramps. In order to efficiently utilize the 4" of stroke I intend to build a lightweight aluminum adjustable height stands to meet the piston rod while in retracted position. Since my accident and having three free floating ribs, I am not comfortable working the stabilizers bent down or laying on the ground. I am also not going to delegate that chore to Mrs, Boatdoc either. This is how this idea came to light and I am determined to accomplish it. Thank you all, for recommendation on the pumps. It looks as I have to place a request with my buddy, the aviation engineer. Thanks "Boatdoc"
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Old 02-08-2011, 06:30 AM   #19
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Hi Smartstream;
Lewster is right on the 3 point system, for as long as the load is proportionally distributed. The single point will find its own level, however on a standard and much flexing frame of an Airstream it may not be enough of side to side support to keep the trailer form swaying on that end while walking inside on that end.

In reference to electronically operated solenoids;
Peter-Paul electronics offers many 12 VDC, 2 way normally closed solenoids with response of 4-16 millisecond response which are also bubble tight and rated at 5000 Psi burst. This range of response and low volume pump, control of pistons can be made very precise. The smoothness of operation depends on volume and valve response time. It cannot be achieved with small volume cylinders and high volume pump. This is exactly why I am looking for a low volume pump so that reasonable response time can be effectively attained. A joystick such as one used by Bennett trim tab system of a boat can successfully operate the pistons in pairs or individually. Mechanical valves would make control of pump in simultaneous mode nearly impossible. Not wanting to go the expensive computerized system, is why I am taking next logical approach. Thanks, "Boatdoc"
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