Do you use your aux tanks?

[ThreeD]

For all four place users

how often do you use your aux tanks capacity?

If you did not add the aux tanks during the build how often do you wish you had them?

trying to decide if the 30 lb of hardware is worth it
DDD

[whee]

I did not install aux tanks so I can’t share any personal experience other than I didn’t want to carry around the extra weight that I didn’t think was necessary for my flight profile. However, a guy I know did install aux tanks and he uses them regularly. He runs mogas and tankers fuel so he doesn’t have to fill up except at home most of the time. He also used to come up to Idaho regularly and would be able to do a bunch of flying before needing to stop for fuel, usually on his way home. Sounds like a pretty great deal to me. If I wasn’t trying to maximize my useful load and performance I would have added them...and I still might.

Some additional thoughts: It takes 50 gallons to fill my airplane and last I checked all of the fuel is usable in straight and level flight. I burn 8gph (ROP) when flying at 125-130 mph or 6.5gph (LOP) at 120-125mph. I can fly a long way for a long time. Additional range isn’t really needed but the option to tanker fuel is what’s attractive to me.

[AKKen07]

That performance is drool inspiring. Wonder if I’ll be close when mine is flying... if I get your numbers +2 gph I’ll be satisfied.

[whee]

I forgot to state LOP and ROP so I edited my post.

It really is pretty awesome performance but I think there is more speed available as I clean up the airframe. I wish I could crank up the RPM and go faster rather than just burn more fuel and make more noise but I suspect my huge prop is a limiting factor.

A guy I know with a O540 BH flies at 125mph and 9gph as his normal cruise setting.

[ThreeD]

Whee,
Thanks I just sold my RV6 and am within 6 weeks of finishing my Pitts, the Bearhawk is next

I am in British Columbia and do plan on making some trips to remote parts, through unforgiving terrain. I do not have a remote cabin so will probably never need to tanker fuel,

I am torn as I want to keep things light,but I am sorely tempted........

I will probably not need them 90% of the time, but what about the other 10%????

don,t think there is a right answer but want to poll others opinions

DDD

[jaredyates]

Something to think about too is not just having the extra 30 pounds gross, but also where those 30 pounds are. Being way out in the wings, the inertia could impact roll feel, especially when the tanks are full. Regarding the philisophical question, each airplane will always have limitations. We usually don't get to conquer them. At best, we get to redistribute them.

[Mark Goldberg]

Something to consider if you are uncertain whether to install aux tanks at first is to install just the fuel lines in your wings going from where the aux tank would be to the wing root where it tee's into the sight gauge. If you do that before closing your wings you can always come back and install the tanks and transfer pumps later if you want. Not too hard. But installing the aluminum fuel lines after a wing is closed up would be much more difficult. Mark

[tailwind]

I use my aux tanks on trips of 200 miles or greater either to tank fuel for a return home or to extend my range typically about 3-4 times in a year. Currently flying about 70 hours per year of which 15 hours would be with fuel from the aux tanks.

[kestrel]

I have aux tanks. No, really, I have AUX tanks. 25 gallons each. Total capacity in the airplane is 100+ gallons. I do use them on long flights so that I can stop when/where I want and buy fuel where it is cheap/easy. That said, my family and I recently did a trip to UT and ID from NH. We started with all tanks full. On the flight out, we decided to lighten the load and stopped using the aux's. Never used them again for the rest of the trip out to UT, ID, VA and back to NH. I have an O-540 and don't seem to get quite the efficiency that some of the fuel injected guys get.

My take: I have them. I use them. I generally don't _need_ them. If I were building a Bearhawk just as I wanted it (I didn't build this one), I would skip the aux tanks and I would wish that each of the mains held and extra 5 gallons. I would focus on efficiency to close the gap: fuel injection (maybe electronic?) and electronic ignition.

I was able to dodge weather and fly a good lap of the country with just the mains. The family was always happy to have a stop for fuel and... If I were up in Canada for Alaska I might choose differently, but I've never been to either place.

A strategy that some use is to carry an extra can or two of fuel. Even if they are in the backcountry without services, they can stop at a strip or sand bar and pour the fuel in the wings.

...and I'd still wish that the mains held and extra 5 gallons each for good reserves. ;-)

[Mark Goldberg]

On the new Model B wing the main tanks do in fact hold 2.5 gallons more each for 55 gallons total. Half towards what you would like. Mark

[robcaldwell]

Oh wow! That's a pleasant surprise!

[kestrel]

Good to know! :-)

[Isilverone]

I have Aux tanks in the 4 place but not my Patrol. I wouldn't dream of building a 4-place without them for my missions. I regularly fly north and just couldn't get where I need to go without them. If I could, I certainly wouldnt get home. Mine are just 10gal per side but its such a great feeling knowing I have them when "Abroad" . Another reason is that I have my own Avgas tank so using my own fuel @ $1.47/L (Canadian) vs $2.10 in the north is very attractive. I often get asked if I could use Auto fuel but premium auto fuel is close to the price I can get avgas at so its not worth it financially. Not to mention that I cant think of 1 airport that sells auto gas and I hate packing Gerry cans around in the cabin.

[ThreeD]

Thanks, I appreciate the input as you probably have the closest idea to the distances between airports in Canada

ALL of my flying will be in mountainous terrain, and along coastal BC

[svyolo]

If the aux tanks in the kit (and plans) were bigger, I might have considered them. I think I will want more gas most often if I am flying with floats, but then I can carry gas in the floats.

[Battson]

Whee,
Thanks I just sold my RV6 and am within 6 weeks of finishing my Pitts, the Bearhawk is next

I am in British Columbia and do plan on making some trips to remote parts, through unforgiving terrain. I do not have a remote cabin so will probably never need to tanker fuel,

I am torn as I want to keep things light,but I am sorely tempted........

I will probably not need them 90% of the time, but what about the other 10%????

don,t think there is a right answer but want to poll others opinions

DDD

You can always put a fuel container inside the plane for that last 10% of the time. Noting the issues.

[ThreeD]

Thank you all,

am planning my build in more detail right now and trying to finalize my plans for the build....

my kit did not have the aux tanks included and will need to get them from Mark if I go that way....

Mark thanks for your input, what is the capacity of the aux tanks? DDD

[Battson]

Mark thanks for your input, what is the capacity of the aux tanks? DDD

Per the Bearhawk website specifications, the capacity is 22 USgal.

I understand it might be closer to 25 USgal, I seem to recall they make the tanks bigger now.

[schu]

I just flew a C170 with 36 gallons from Alaska to Washington state. I wasn't hurting for fuel, in fact, I was usually looking forward to getting on the ground so I could pee.

I just don't see anyone ever using the aux tanks for range, it's really just to have the ability to pick/choose where you buy fuel.

In Alaska, in the bush, fuel is $8 gal, so having aux tanks save you a lot of money really fast, but in the lower-48, I don't see it, unless you are running lots of mo-gas, but in my opinion, using fuel injection and knowing how to safely do LOP gives you near the cost savings of mo-gas and you don't have to search for it.

Anyway, I'm seriously considering omitting the aux tanks from mine. Seems like it would save me at least 10-15lbs.

schu

[Mark Goldberg]

Bob has said that the tanks, transfer pumps, and fuel lines add 30 lbs. Mark

[AKKen07]

My latest case is only marginally relevant but I just attempted a hunting trip to a remote island outside Cordova in a Citabria and having Aux tanks would have saved me A logistical headache. That is... if the hunt wasn’t weathered out the 1st day :P. I often wish for greater fuel capacity on long trips - refueling locations are often limited by weather this time of year too. I decided Aux tanks were necessary.

[nichzimmerman]

If you ever sell the airplane, a ~25 gal increase in fuel capacity will speak louder to a prospective buyer than a ~25 lbs of extra empty weigh, especially if you have a thirsty engine.

While you may never NEED extra gas in the lower 48 (other than float plane ops or mogas tankering), you may find yourself wishing you had it when your desination has very pricy gas or a broken fuel pump and you need to add an otherwise unnecessary stop just to fuel up. Or when your remote destination has an unforcasted overcast layer and extra gas enables you to comfortably circle for 45 minutes before diverting. Or when you wake up from camping and realize your left main is nearly empty because your drain valve was dripping fuel all night. Or so you can give a full day of rides at the small-town strip without returning to civilization to fuel up. Or if you just want the airplane to be heavy to smooth out a bumpy ride somewhat.

Ultimately, OCONUS travel and mogas usage drove my requirement for extra gas, but the above experiences (in non-Bearhawk airframes) stifled any second-guessing. But the great thing is, you can do whatever you want, or postpone the decision by installing just the lines.

-Nic

[kestrel]

...that 25 (30) lb decision is made multiple times in the build of an airplane and they add up. Each has to make their own decision as to which are worth it. I still put the 100+ lb decision of a 540 in the "worth it" category. For myself, I'm less certain about the aux tanks.

[zkelley2]

Depends on your mission, but even with the aux tanks I'm reasonably certain I'll have fuel in the cabin on occasion. I'm actually somewhat jealous of your dual main tanks.