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For a military 700AP - anyone know the CG?

Posted: Mon Sep 25, 2017 7:14 pm
by Czechsix
I'm sure that for the RAF models, and some others, there were Center of Gravity figures that were researched.

Does anyone have them for a 700AP?

I'm trying to figure out some trailer loadings prior to hacking on the trailer and modifying it, but if it comes down to it I'll just use empirical methods.

I'm gradually getting ready for the Calico Mogfest.

Re: For a military 700AP - anyone know the CG?

Posted: Mon Sep 25, 2017 8:08 pm
by heinkeljb
I haven't seen that sort of information anywhere, not to say it hasn't been done, but it might be better to get detail from your specific Haf if you are the one who is going to make use of it!

First thoughts on how you might do it.

Make sure the Haf is empty or at least only carrying stuff that is always going to be there and always going to be in the same place.

Put Haf on a single axle trailer and just move it back and forth until you find the balance point, then take measurements from the front and the back. (or from the wheel base)
Another idea:
Get a round 6ft fence post, couple of axle stands and a trolley jack.
On flat ground, jack up either the front or the back as you please. Place the axle stands approximately in the middle of the wheel base, put the fence post on top of the axle stands.
Lower the trolley jack slowly with someone stopping the Haf from tipping sideways. Check to see if it balances. If not, then jack it back up and move the fence post and axle stands one way or the other depending on how unbalanced it was with the first attempt.

John

Re: For a military 700AP - anyone know the CG?

Posted: Mon Sep 25, 2017 8:31 pm
by Czechsix
Thanks John,

Yes I was trying to make it a bit easier than doing the empirical path. For U.S. military vehicles, it's easy to find sling load data and CG data. All of them have data plaques installed that clearly shows the figures, but I'll bet for the RAF model of Haffy that data is out there. Has to be for aircraft loading.

I'll probably just load it on the trailer and go from there, probably try rear towards tongue first.

Re: For a military 700AP - anyone know the CG?

Posted: Mon Sep 25, 2017 9:43 pm
by Julian B
As an aside, did the RAF ever have Haflingers? I know the Royal Navy did (aka the Fleet Air Arm), but can't recall references to the RAF per se?

Re: For a military 700AP - anyone know the CG?

Posted: Tue Sep 26, 2017 1:46 am
by AustHaflinger
The Australian Army used Haflingers and did airlift them - one got written off when dropped too hard. While larger Aussie mil vehicles had CofG marks on the vehicles (my 101 has them) I do not recall seeing the same on the Haflingers - I have looked at all the pics of have of Aust Mil Hafs and cannot see any (that is not to say they are not there). However realistically, given the small weight vs the strength of lifting straps maybe they were not needed.

As far as building a suitable trailer - maybe you are over thinking this a bit. As long as the axle of the trailer is about mid way between the Haff wheels you will not have an issue - all I have sighted have the front of the Haff at the front of the trailer. Here the trailer axle has to be behind the mid point of the load area to ensure there is always nose weight on the coupling.

Here are some pics of mine in my 750kg trailer - loads level and tows fine.
P9290130_zps362d155b.jpg
P9290131_zpsb628a34b.jpg
P4210029.JPG
Garry

Re: For a military 700AP - anyone know the CG?

Posted: Tue Sep 26, 2017 7:43 am
by heinkeljb
I believe the weight distribution is 47 / 48 % front and rest back - to take into account the driver which would make it even front and back, so Gary's call on it being about half way would be correct. I don't remember where I read that bit of information so can't go and re-read it to find out if it had any other pertinent information.

Depending on where you live climate wise, put it on front first, drop the roof covering and drop the the windscreen and that should put it below the towing vehicles wind blast - should make for less impact on fuel consumption, drag etc.

John