TIP TANKS FOR PA-24-250

[bartsch]

I am installing tip tanks on my pa-24, I was wondering where I should go to research how the plane will react (Va, crosswinds, ground effect, etc) with the new tanks, any suggestions?

[Kristin Winter]

Not meaning to be flip, but I would suggest the traffic pattern. You may not notice the difference in handling. You might notice a bit more airspeed at higher altitude.

[Hank Spellman]

I have had tip tanks on my 250 for years. The only thing I have noticed is a very slight increase in IAS at and above 8000 feet.

I would also suggest that you also strongly consider an Aero-Trim electric aileron trim tab (http://www.aeroresourcesinc.com/store_/). Price is $795. Installation is fairly simple. The electric trim allows you to trim out a heavy wing for coordinated flight so you don't have to hold a constant pressure on the yoke, or, if you have an autopilot, it saves the servos running all the time to stop the roll. An imbalance in the fuel quantity in the tip tanks can result in quite a hand full. Trying to burn from both tips at the same time does not work (impossible on the models originally equipped with four tanks, but possible on the two tank models). What happens is that the fuel will transfer through the selector valves and down into the lower (in altitude) tank, making it even heavier and even more below the level of the other tank. Eventually, the lower tank will overflow and the fuel will go overboard.

This particular arrangement can be used to transfer fuel ON THE GROUND ONLY from one tip to the opposite main by selecting one tip and the opposite main. The fuel will run out of the tip, through the selector valves, and into the opposite main. This trick can be used to get an absolutely full main tank. The tips then have to be topped off again. It will only work on the early model 250's (1960 and earlier). It will not work on the later singles because the plumbing for the tank selection is different.

I hope this helps.

Hank

[Jay]

Good on you, that's really the best mod for Comanches that there is. I honestly don't ever even think about differences in handling with full tanks versus empty. The slight increase in speed is real, and the extra range and W&B flexibility is great.

Jay

[David Pyle]

Hank Spellman is far better looking than his picture.

Looks like he is "tipping" more than avgas.

[Chief]

Brent,

Our Comanche 250 has tips. I've had it for 2 years. Love them. It definitely helps in a crosswind, always plan more fuel in your upwind tank, it will be heavier and it helps dip into wind. DO BE CAREFUL with an imbalance if you don't burn tips at same rate, you will get a (hopefully noticable) wing dip. Very noticable in the day and VFR. Night/IFR, pay attention!

Not sure about crossfeeding, never tried, probably never will, not good to run tips dry per the manufacturer. I'm afraid I'd run them dry and get air in lines.

I always keep tips full of fuel. Best speed mod made, you don't have to land and refuel.

One last thing, your Vna speed changes, it drops, so be careful to slow down when turbulence or manuevers require it. It is in the Osborne notes!

But I highly recommend the upgrade.

[Zach Grant L1011jock]

Brent,
You will find more roll inertia with the tip tanks installed and full, vs a stock airplane. This helps in turbulance as there is less displacement from vertical gusts, but it will also cause slightly less responsive handling, as well as additional inertia once the roll does develop. One of the big errors people make is at slow speed, setting up a PIO in roll (310's are especially bad for this). Not doing this is simple. Don't make control inputs you don't want the aircraft to follow! Realistically on a Comanche, you will not notice any difference with them installed/empty, and you will only notice a real difference between empty and full if you are looking for it. Fly the plane, make it do what you want it to do.
-Zach