Cruisair C.G. and battery placement

twheel47

twheel47

New member
I have noticed over the years that Cruisairs tended to have ballast weight (lead) affixed to the tail post when they left the factory and it only got worse as each later model had the battery migrating aft. Starting on the forward side of the firewall for the Cruisairs to under the passenger seat to under/behind the baggage area and finally at the stabilaizer L.E. in the14-19-3A and all Vikings.

I used my IA weight & balance shift app and determined that in crude numbers the CG would go just under 1" aft if the battery went under the passenger's seat and 1.7" if under the baggage compartment (not allowing for the weight (expense) of the required cabling incease. That could be handy, especially in the landing flare with low fuel.

My question is, How many Cruisairs have had the battery moved aft to compensate for the nose heaviness? Anyone have information or documentation?
 
if you say so about the lead. Not present in my a/c.

The worst case c.g. scenario for my particular example would be 2 empty tanks
and big pilot ( me 210 lbs) and not much else... which puts the C.G. right at the ragged edge of the
C.G. Limits. ( but my panel is sparse).

For this reason, I keep about 15 lbs of stuff stowed in the baggage compartment at all times.
1-2 Qts of oil, the rope tow bridle I use to tow the plane out of the hanger, tupper ware bin
with gloves, screw driver, gasoline try glass, rags, the calibrated fuel dip stick, and wheel chocks.

Usually there is flight bag and jacket or sweater in the back seat.. another 10 + lbs..
but not always.

I always need the stuff, it's too dirty for the cabin, and it insures that I cannot get the C.G. negative.
Unless you have orig small tail 14-13 rather than a later version, I cannot imagine you running out of elevator.

Dan C.. what say you ?
 
In all my years of dealing with Cruisairs...40+...I have never seen factory installed weight in the rear of the airplane.
Cruisemasters do, for the most part. Almost all Cruisairs were delivered with a "calculated" weight and balance sheet.
Check your paperwork for that and if you don't have it, it will appear in the FAA records file. This means that the factory did not do a real weight and balance on the airplane. They knew the c.g. of a basic constructed airframe and adjusted the c.g.
for the equipment installed, as delivered.
The company felt confident enough in their weight and balance program that Cruisairs were delivered with the battery installed at the firewall. Now, given some 50 years or so, with owners throwing all kinds of weight in the airplane....most of which is forward of the original cg., we end up with a forward cg. issue. Being at or near the forward cg. limit, according to most aeronautical engineers is not as bad as being at or near the rear cg limit. The airplane is more stable and predictable near the forward cg. So, don't get in a panic if your airplane, under certain conditions, is at the forward limit.
Batteries are heavy and necessary and tend to be the first thing moved to remedy a forward cg issue. This is certainly better than adding useless weight at the tailpost. My Cruisair has the battery under the luggage compartment because I have a slightly heavier Franklin 180 driving a much heavier constant speed propeller.
It is very common for all Cruisairs to be at or near the forward limit under certain circumstances. Like Blimpy, I like to load up the rear of the airplane first. It does help with the cg and the airplane will fly faster because you won't be loading the elevator/horizontal stabilizer as much.
 
My Cruisair's factory W&B was a Calculated W&B as you said. The second owner did an alteration to remove the flares and his 337paperwork states "Ballast required after remoal of flares to meet weight and balance requirements." Larry D"Atillio once told me his Cruisair also had weight in the tail.

I also carry "stuff" in my baggage compartment; some oil, a few tools, dipsticks &rags,Claw tie-down kit, windshield cleaning stuff, etc. There's enough elevator to flare the plane but not enough trim to fly at 75-80 in the patern without yoke back pressure. Trips are never a problem due to a Bruce's Custom Cover and normal baggage. My son and I usually fly it locally with a pair of 25# barbell weights also. That makes sense since the 10# of weight at +185 the fellow put in after removing the 17 # of flares at +86 are long gone. Apparantly the flares, racks and wiring was heavier than I imagined.

I've unearthed two Bellanca, Inc. drawings about the battery installation under the baggage compartment that looked like would make a helpful C.G. shift.

Just looking to see if anyone has done it or currently owns a Cruisair that was modified like that.

Scott
 
Tailwheel, could you post the factory drawings that you have? My first Cruisair (project) had the battery under the copilots seat,according to the logs. It was actually on the firewall like most Cruisairs. I have a project that is STCd for the Franklin 180, but it doesnt require the battery to be moved from the firewall. A friend (Frank Cotten) said that when he did the Debs Aero 180 STC, that his plane always seemed nose heavy afterwards. A 150 with a wooden prop, to a 180 with a constant speed is about a 60 lb difference, all forward of the CG. Bruce Kown once told me that with a Skyteck starter, a Stan Bedford alternator, helocopter intake logs, and slick mags, he could get a 180 almost down to the weight of a 165 with an Aeromatic. He said he turned the battery box sideways on the firewall to get into CG. I have a faint memory of reading that straight 14-13s that were flown solo needed a small amount of weight in the baggage compartment, but cant swear to that. I just always assumed that needing back pressure on final was normal. ______Grant.
 
Mine wont trim for approach speeds either. annoying at first, now I don't think about it much.
but it would be nice ! :D
 
80 mph+ glide was the slowest trim speed I could get with the 14-13-2 even with those heavy flares installed. So, I concur with the above reports that the high glide trim speed is sort of normal. I did do a full taping of the elevator trim tab slot and it helped reduce trim speed some. Otherwise, a doll baby landing, forward CG or not.
r
 
My 14-13-2 with a 150 and Aeromatic would never trim below 80 with only front seats filled, and required some backpressure in the pattern. It did wheel land easily. Our current 14-19-2 will run out of elevator with empty aux tank and only the front seats filled if you are slow on short final with the power off. Adding a little power gets your pitch control back but it is disconcerting to run out of elevator.
 
I had the same problem with my 14-19-2 when I first got it. I re-check cg comutations because that shouldn't be! I found up elevator control was out spec. I guess it was that way since it was recovered about 20 years prior to my purchase.
 
Checking rigging specs is a good idea. On the first annual after I got my Cruisair, I discovered that the right rudder travel was only about 2/3 of what it was supposed to be. It may have been that way for decades. If I had ever been foolish enough to spin it, I might well have become a statistic. The plane didnt even have the no-spin placard on the panel. Lots of little things can be wrong, and not be noticed. I am looking forward to Dans article on rigging. ______Grant.
 
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