# Thread: Aerial apparatus turning radius

1. ## Aerial apparatus turning radius

More basic aerial questions:

Ignoring the platform/straight stick debate...

75' single axle vs 90-100 dual axle vs 75' dual axle all with 500 gallons and a pump.... is there really that much of a turning radius difference? (curb to curb and bumper to bumper)

We have alot of victorian era 3 story buildings (on the verge of collapse ) that have 12'+ floors, 2 large mining operations, and few true 4 story buldings, and a five story. Plus grocery stores and hardware store.

Streets are on average 40 feet wide with parallel parking on each side.

So the question has been raised about 75' or bigger. I am headed out with a tape measure and some geometry (what was that cos/sin/tan crap )

No extended bumpers, short as possible wheelbase, and a decent angle of departure as we are not flat. Chassis also has to support 500+hp as we are at 10,000 plus feet.

2. I do not know the geometry of single vs. tandem axles, but I know that to compare apples to apples you need to spec what really matters: Wall to Wall turning radius. The track of the wheels mean little if you "tailslap" a car in an intersection or keep taking out stop signs. Wall to wall gives you the width needed to turn the truck 180 degrees. This includes the tailslap and front overhang. This is important with any type of truck as rearmounts generally have front overhangs (not all) and mid mounts usually have long tails (everything behind the rear wheels). The newer chassis's offer great cramp angles and tighter turns but this also makes tailslap a larger concern. As part of our final bid evaluation process we requested the minimum wall to wall radius for comparetive purposes.(midmount tower).Also, don't trust you tape measure and mathmatics, make the dealers bring some trucks and drive them around. Know for certain that they'll go where you need them to!

3. Yeah, everything RFDACM said!

Also, something to consider:

Trucks with tandems usually pivot on the front tandem (they have a floating rear axle). Hence, a little bit tighter turning radius than a single rear axle with the same wheelbase (that would be placed in the center of where the tandems are).

For instance: we have three 100' rear mount tandem axle towers that can actually slightly turn inside our two 75' rear mount single axle quints even though the overall length of the tower is more. They are all from the same manufacturer with the same basic chassis design and the same front axle cramp angles. It just so happens that the distance from the front axle to the front tandem on the tower is slightly less than the wheelbase of our quint. Since the towers pivot on the front tandem, that makes all of the difference.

4. Oops, forgot to add...

Don't forget your setbacks!!! Yes, a 75' ladder can reach the roof of a 5 story building but only if it is parked very close to the building. If you must position any distance away from the building whether you got blocked out by the engine or there are parking spaces or landscaping your rig will be less useful. We have some 3 story apartments buildings that our 75' rigs can't reach because of setbacks and parking areas. Please do consider this and if you have any doubts you might want to look at a 100' rig.

5. Not to stir the pot,but figure your radius from the center of the rear axles(bogies),that is your ACTUAL turning point NOT the leading x.Hence the CB designation,center of bogie.Check it in a parking lot sometime,you'll see what I mean.Usually less than 24" from the leading axle but 2' is 2'. T.C.

6. Like I was saying: too many variables in turning radius's (radii?). Tell the prospective buildiers that you want the minimum wall to wall 180 degree turning width. This considers the whole package as specced. Given the vairaibles in axles, wheelbases, cramp angles and front/rear protrusions you cannot go wrong requiring the wall to wall.

You can do this with your current apparatus to get an idea of what you expect or require the new piece to do.
Start with the truck stopped. make an immediate turn at full tight cramp until the truck has reversed direction. You must ensure someone cna mark the tail slap spot when the truck first takes off into the turn and the front bumper's furthest point just as it comes to the end. The distance between is he overall wall to wall. The starting point is quite important as with many trucks the tail will 'slap' out over the curb.

7. For turning radius I would consider a rear mount over a mid mount. Our 95 foot midmount has a 17 foot over hang from the middle of the tandem rear wheels to the back bumper, not including the distance the monitor sticks out. This is greatly diminished with our 95' rear mount since the bucket hangs over the front of the truck. Just some food for thought.

8. This is just one point to consider in the decision of what type or aerial to purchase. You must determine what you expect from the truck and then see which type can best fit the bill, then can you manuever it around town? Will it fit in the station (length/height)? How's your driver training program? Without a decent program and good drivers transitioning from a rear mount to a mid mount could be disasterous. There are many distinct advantages but they certainly pose a problem where you can't ensure quality drivers.

9. Originally Posted by TVFDT141
For turning radius I would consider a rear mount over a mid mount. Our 95 foot midmount has a 17 foot over hang from the middle of the tandem rear wheels to the back bumper, not including the distance the monitor sticks out. This is greatly diminished with our 95' rear mount since the bucket hangs over the front of the truck. Just some food for thought.
While all mid-mounts have a long tail and tailslap issues, your's (E-One) has the worst tail length and angle of departure. Others do not have the bucket as the rearmost point either. But you guys still run it successfully? So it works for you. Plus with all the stip malls having the ability to put the bucket at sidewalk level is a true tactical advantage. That being said, I understand you have one of each (rear-mount and a mid-mount tower) in town? Course if I lived in Vernon I'd be to fat from eating at Rein's to be on the FD!

10. Originally Posted by RFDACM
While all mid-mounts have a long tail and tailslap issues, your's (E-One) has the worst tail length and angle of departure. Others do not have the bucket as the rearmost point either. But you guys still run it successfully? So it works for you. Plus with all the stip malls having the ability to put the bucket at sidewalk level is a true tactical advantage. That being said, I understand you have one of each (rear-mount and a mid-mount tower) in town? Course if I lived in Vernon I'd be to fat from eating at Rein's to be on the FD!
Living in this town my entire life, I have only been to Rein's a handful of times. And there is no reason why. They do make incredible food. We do have both a 95' mid mount and a 95' rear mount. Going into the Rockville section of town makes for some difficult manuvering. We have alot of very steep streets which the overhang poses some issues. I would say that there are only a handful of locations where both aerials can not be set up. To answer your question, I feel we are able to run it successfully.

11. Where I am there's no good deli's. Not many ethnic food places in general, certainly no Jewish Deli. Man, one of each rear mount and middy, that's great. As I recall Manchester has a stick (career?) and a midmount sister to yours (vol.?)

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