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Dakota cub battery box

D

d dyre

FRIEND
I see Dakota Cub has a new battery box that mounts in the boot cowl. It would be great with in panel electrical system. The only problem I can see is that CG might get pretty far forward. Anyone have an opinion?

Dan
 
You're right. It will be pretty far forward. I don't think it's a good idea and not sure where you'd find space on the firewall to mount it...

Crash
 
I've been putting them inside boot cowl(rt side) with external door for many years too, very nice short electric runs to dash, just fits there on -18.....

but anymore I just use atlees under seat pan....
 
Crash,

You could mount an Odyssey battery on the firewall if you had a Sutton Exhaust. I saw one on a PA-12. It was a very nice plane. That exhaust really opened up the backside of the engine to allow installations like this.

Kevin
 
If anyone LOST their battery box (the ol' original type w/lid & drain) I have one that you can have. I just didn't throw it away 'cuz it's an airplane part. :) I can imagine these are easy to lose. :)

Just pay the postman.
 
I have the Atlee Dodge box under the seat but if I had it to do over, I would go with the Dakota box located in the boot cowl. It would not be a significant balance penalty for almost any SC on wheels and would be easier to service and jump. The exception would be an 0-360 SC on amphibs. In one of those, with just a 200 lb pilot in the plane the center of gravity is right on or just forward of the allowable weight & balance envelop so the battery should go further back.
Here is the Dakota setup in a friend's wide body SC that Bob Schefter built up in Fergus Falls, MN.
PB060003.JPG

IMG_05151.JPG
 
Thanks for the information. I suppose that there's not much CG difference between the pilot seat and the boot cowl. Sure would be an easy install.

Dan
 
If you want to study the installation, just go to the gallery and bring up the photo of the installation with the boot cowl off then click once on the medium size picture. That will blow it up to the point where you can study minute detail. You also can calculate the effect of moving the 15 to 20 lbs forward from the pilot's seat to about 2 feet forward. I don't think this will be a deal breaker except for nose heavy SCs on amphibs.
Darrel
 
Weight and balance might not be critical until you get to amphibian Cubs, but then it starts to be really serious. I think a pilot and fuel puts you forward of the forward limit unless you load some bags.
 
Here is an example of a fairly heavy SC on Amphibs. This is one of two similar SCs I know that weigh about the same. These are wide body SCs with the 2000 lb upgrade on Wipair amphibs and an 0-360 engine.
Darrel
Points:
A = 200 lb pilot with full fuel (44 gal) and 25 lb baggage.
B = 200 lb pilot with 25% fuel and 25 lb baggage
C = 200 lb pilot with full fuel and 75 lb baggage
D = 200 lb pilot with 25% fuel and 75 lb baggage
Example_of_SC_on_Amphibs.jpg
 
Darrell:

Thank you for the information. This thing has 2000 gross and hyd. pump installed do it might see amphibs someday. It has hyd. skis as well and is nose heavy in that mode. So maybe the battery should stay in the tail. Guess I'll have to do some math.

Dan
 
The TCOW Cub which I am building on floats with an IO-360 (180hp) is going to have the battery mounted at the very aft end of the extended baggage for weight and balance purposes. If necessary I will add lead to the tail to keep the CG aft. This will optimize takeoff, climb and cruise.
 
skywagon8a said:
I will add lead to the tail to keep the CG aft. This will optimize takeoff, climb and cruise.
Click to expand...


umm a good tool kit bag is a more "useful" idea...

then you can move it up when loaded if needed...... unless you need the lead to get into CG range, and you can just require the bag of such weight stuff there as required equipment on your W&B sheet......instead of useless dead weight..
 
mike mcs repair said:
skywagon8a said:
I will add lead to the tail to keep the CG aft. This will optimize takeoff, climb and cruise.
Click to expand...


umm a good tool kit bag is a more "useful" idea...

then you can move it up when loaded if needed...... unless you need the lead to get into CG range, and you can just require the bag of such weight stuff there as required equipment on your W&B sheet......instead of useless dead weight..
Click to expand...

I agree to a point ,which is, in Darrel's example it takes 50 pounds of baggage (tools) to move from point A to C. I would use 10 pounds of lead at the tail and have 40 pounds left over for 6.6 gallons of more gasoline. Or, just a lighter plane for performance. Of course one could make a small baggage compartment under the stabilizer where you could store rocks for disposable ballast. :lol:
 
Just for kicks, here is the same Super Cub but now on 8.50 x 6 tires. Note that the allowable W&B envelop is different for wheels compared to amphibs. The points are a little different -- more baggage.
A = a 200 lb pilot, 44 gal (full) fuel and 25 lb of baggage just as before.
B = just like the other example is the 200 lb pilot, 25% fuel and 25 lb baggage
C = a 200 lb pilot, full fuel and 85 lb baggage
D = a 200 lb pilot, full fuel and 145 lb baggage
E = a 200 lb pilot, 25% fuel and 145 lb baggage
Note that even a fairly heavy SC on wheels is difficult to get outside the envelop with just the pilot on board. Note that no one is in the backseat but the plane can carry 2 big people and full fuel but with no baggage.
Darrel
W_B_of_SC_on_8_50s.jpg
 
Thanks Darrell - those pretty much compare with what I found. Note that the forward limit is well aft of that on floats - I know you mentioned it but a casual glance will not tell the reader that it moves aft on wheels.

Two recent examples of weight/balance problems:

A friend has an amphib (not a Cub) that purportedly can carry half fuel so long as there is nobody on board. Forgot to check that before the floats were put on? The Super Cub amphib is about the same way before the essential 2000# STC.

And a gorgeous J4 showed up a month ago - it had a 16 gallon tank ahead of the pilots, and a six gallon tank in one wing. Funny thing; the useful load in this show stopper was under 400 lbs - two guys my size and no fuel and you are good to go. Cannot get in too much trouble with that much fuel.
 
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