Aerial Stability Question?

MFDPhoto1

USAF-SAC/Vet.
Massillon, OH
1948

I've had this photo for over 60 yrs. of a 'public demonstration' by MFD on their 1941 Seagrave 65' steel aerial. A fireman (BTW my Dad), with the ladder at full extension in horizontal position, walking the entire length from tip to the turntable, supported by only two 2" hydraulic jacks, mounted inboard directly from the frame to support the truck in that position, and WHY IT DIDN'T TIP OVER ON IT'S STARBOARD SIDE. ??

Many aerials of that time, did not have 'outrigger' stabilizers as all do today, which made them convenient for access in narrow alleys and streets with vehicles parked on both sides, where outriggers cannot be used.
 

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johnmocha

Firefighter
My guess is in that looking at the ladder it is of much lighter construction than today's ladders. Yes, the apparatus itself is much smaller but I'm guessing the ladder is much lighter on a ratio basis. Given that, and my statics and dynamics engineering class, there is simply much less weight exerted over the length of the ladder hence less counterforce necessary. Also, folks weighed a lot less back in the day. ;)
 

MFDPhoto1

USAF-SAC/Vet.
johnmocha said:
My guess is in that looking at the ladder it is of much lighter construction than today's ladders. Yes, the apparatus itself is much smaller but I'm guessing the ladder is much lighter on a ratio basis. Given that, and my statics and dynamics engineering class, there is simply much less weight exerted over the length of the ladder hence less counterforce necessary. Also, folks weighed a lot less back in the day. ;)
Thanks for your opinion, however; the Seagrave ladder was Steel not aluminum as most are today. Laying 'it' flat would exert more stress on the attachment point on the turntable, like trying to raise a ground ladder from horizontal on the ground, opposed to having it at a 45 deg. angle...?? Also, the fireman on the ladder weighed at least 160 lbs. as I recall.
 
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