Flint wing tanks?

[JimNelson]

I'm looking to get a bit more range out of my 170A. I'm considering the Flint wing tanks. I like that they are close to the center of gravity vs. in the baggage compartment, but I'm willing to be convinced that baggage fuel is the better way to go. (But I'm not really comfortable with fuel behind me vs. out on the wings.) Cost isn't really a consideration (it's an airplane!)... more about utility and convenience. I don't want to swap wings with a 175. While I like the Del-Air "just a bigger fuel tank" I don't know if that's still being done or being done outside of California.

I've scoured the forum and found reviews from "a bit kludgy" to "works great". So, from those with opinions: How was the installation? About how long did it take? Is it working for you? Would you do it again? Are there other options?

Thanks!
Jim

[GAHorn]

I”ve not done it, but I did look into add’t fuel capacity by replacing original 42 gal tanks with 52 gal C-175 tanks. The labor was estimated to be $7500 in 2010. I suspect it may be higher today. The useable fuel placarded in the 175 is only 43 gals… but operators of that airplane commonly report that cruise and descent profiles allow full useage. Adding-in the likely cost of the tanks and whatever fuel-gauging system selected, causes me to believe the conversion is simply not worth the extra 1.2 hrs endurance to be expected. You don’t want to swap wings, Jim…but that may be the most expedient way to gain extra fuel if you can find corrosion-free C175 wings….which can be a challenge in itself….the 175 had a reputation it suffered from corrosion more commonly than other Cessnas.

The Javelin tank is not currently available as a complete kit and collecting the full list of parts could be problematic. Some of the parts would likely have to be custom-mfr’d. I also do not like the idea of fuel within the cabin area. The O&N bag-comp’t modification which was available for the C172 was never offered for the 170 series as far as I know (and I was curious as to why that was the case) but it little matters any more since O&N are no longer offering that system. An owner would face a similar problem scavenging salvage parts and then also face the task of gaining approvals. The labor would appear to be easier than wing-tank changeouts.. but 2 hrs of addt’l endurance would be unecoomical, IMO.

The Flint tanks provide a little more than 2 hrs, the fuel is out in the wings, and otherwise operates similarly to the Javelin/O&N systems, in the sense of requiring electrical pumps to transfer the fuel to the main tanks. The unlikely loss of a pump would mean unavailable fuel, which should be considered.

It’d be nice if addt’l tanks could be installed plumbed to the main tanks similar to what the 170 “ragwing” system allows…but I’ve never pursued that option. I’ve never known of anyone attempting to utilize 182 wings with the 182 long-range fuel system, (reg approx 60 glas, L.R. approx 90 gals) although in theory that should be possible. The bladder tanks can introduce a different set of problems. In any case, adding 10 or 20 gals of fuel to a 170A or B is costly. After considering the options again due to your post…. I think I’d favor the Flint solution if I really needed more range.

Here’s the Flint Flight Manual Supplement: http://flintaero.com/wp-content/uploads ... e-5-06.pdf

[JimNelson]

Thank you for the great reply! It looks like Flint may be the best option. I'll have to look more into swapping wings. Finding polished 175 wings might be a problem so they match the rest of the plane. I really appreciate the advice.

Normally the 170's range is plenty for whatever I want to do. I'm finishing my instrument rating. Adding up the fuel for approaches, holds, fly to alternate, and then 45 minutes means the standard fuel for an IFR flight is less than I'm comfortable with. Add to that no takeoffs or go arounds with less than 1/4 tank and it gets tighter.

[n2582d]

… I'm considering the Flint wing tanks. I like that they are close to the center of gravity vs. in the baggage compartment … .

That’s true regarding the longitudinal CG but not the lateral CG. Aux tanks at the wingtips make for slower, less responsive ailerons. I think the ideal aux tank would be a fuel cell in a carbon fiber belly pod similar to this but no one makes such a thing for the 170. Lowering the CG would help short field landing performance. On the other hand, a belly pod not only increases empty weight, it also increases parasitic drag.

Cost isn't really a consideration (it's an airplane!)... more about utility and convenience. … While I like the Del-Air "just a bigger fuel tank" I don't know if that's still being done or being done outside of California.”

If cost is not a consideration, Del-Air’s STC is what you want. You’ll pay north of 8K for the 72 gal. (67 gal. usable) tanks compared to Flint’s 6K STC. As far as I know Chris Shaw is still in business at Del-Air. (559) 784-9440. His workmanship is outstanding. Unfortunately, as far as I know, he is a one man operation so has a significant backlog of work. If you’re in no rush but don’t want your plane down for years, buy a set of 170A, 170B, or early model 172 tanks from a salvage yard and send them to him. He’ll weld on the extensions and ship the tanks and required hardware back to you.

It looks like Flint may be the best option. … .

I did some rough weight comparisons of my standard 170B tank and cover to that of my 36 gallon Del-Air tank and cover. These weights don’t account for ribs removed or doublers added and were done on a cheap fish scale so can only be used as ballpark figures. For an additional 30 gallons useable the Del-Air tank and covers add 26 lbs. to the empty weight. Flint’s website says that for an additional 23 gal. usable the empty weight increases by 40 lbs. on their system.

… Adding up the fuel for approaches, holds, fly to alternate, and then 45 minutes means the standard fuel for an IFR flight is less than I'm comfortable with. Add to that no takeoffs or go arounds with less than 1/4 tank and it gets tighter.

As you know the cork float wing fuel quantity gauges are not known for their accuracy. I think you’re needlessly penalizing yourself by using the gauge’s red zone - 10.5 gallons total - as unusable fuel. The TCDS lists unusable fuel as 5 gallons. Theoretically you should be able to do a go-around as long as you have more than 5 gallons of fuel on board. Just for the peace of mind my suggestion would be to install a fuel computer if you don’t already have one.

[GAHorn]

It might be of interest to know that the 1/4-tank “no takeoff red zone” of the original indication system is not an operating prohibition and in fact …not mentioned in the AFM at all. It may be simply a Rochester/Scott creation for a gauge they hoped to sell to a variety of different aircraft models.

[JimNelson]

It might be of interest to know that the 1/4-tank “no takeoff red zone” of the original indication system is not an operating prohibition and in fact …not mentioned in the AFM at all. It may be simply a Rochester/Scott creation for a gauge they hoped to sell to a variety of different aircraft models.

The 170A POH says that "Take-off on less than 1/4 tank is not recommended". I don't know if that's because it's an aircraft thing or that they want people to be safe and take off with enough fuel to go somewhere. In addition, are the big red "no takeoff red zones" on the fuel indicators considered placards and are thus regulatory and prohibited, or are just there as recommendations? And with the engine drawing 60% left, 40% right, the left tank gets lower than 1/4 before the right tank. Should I not take off when both are less than 1/4 or I'm OK if just one is less than 1/4? Clearly I'm overthinking the issue

But I'm agreeing with you. The manual says not recommended, and so is not prohibited. The gauge is a more strongly worded recommendation. I do have a fuel flow and total remaining in my engine monitor. Someday I'll replace the current gauges with electronic. If only to make them easier to see without stretching my neck around.

[JimNelson]

If cost is not a consideration, Del-Air’s STC is what you want. You’ll pay north of 8K for the 72 gal. (67 gal. usable) tanks compared to Flint’s 6K STC. As far as I know Chris Shaw is still in business at Del-Air. (559) 784-9440. His workmanship is outstanding. Unfortunately, as far as I know, he is a one man operation so has a significant backlog of work. If you’re in no rush but don’t want your plane down for years, buy a set of 170A, 170B, or early model 172 tanks from a salvage yard and send them to him. He’ll weld on the extensions and ship the tanks and required hardware back to you.

I really like that idea. Either way it's fairly major surgery, but I'm in no hurry and the local shop also has a large backlog. I'll go down that road a while and see what I find. It seems that used but usable tanks should be relatively plentiful.

On the other hand, a bit more roll stability might be a good thing. The responsiveness and light touch that makes the 170 such a delight to fly VFR makes things go interesting in a hurry when I'm under the hood and playing with the GPS.

[n2582d]

Jim,
If you do decide to go this route and if Faeth Aircraft Salvage (near Sacramento) has tanks, I’d be glad to pick them up and deliver them to Del-Air for you. Our daughter works for Sequoia National Park in Three Rivers, not far from Del Air in Porterville so it would be a good excuse to visit her. Be aware that Del-Air has both the 14 gallon and the 30 gallon extended range options. I believe John Barrett has the 14 gallon extensions so he would be the one to talk to about the pros and cons of this modification.

Faeth Aircraft: 916-368-1832

[JimNelson]

Thanks for the offer! I'll start with the research to see what's feasible and the costs. What's interesting is after the upgrade, I'll have the old tanks from my plane out and available to the next person who needs them. I truly appreciate all the help on this forum!

[GAHorn]

It might be of interest to know that the 1/4-tank “no takeoff red zone” of the original indication system is not an operating prohibition and in fact …not mentioned in the AFM at all. It may be simply a Rochester/Scott creation for a gauge they hoped to sell to a variety of different aircraft models.

The 170A POH says that "Take-off on less than 1/4 tank is not recommended". I don't know if that's because it's an aircraft thing or that they want people to be safe and take off with enough fuel to go somewhere. In addition, are the big red "no takeoff red zones" on the fuel indicators considered placards and are thus regulatory and prohibited, or are just there as recommendations? And with the engine drawing 60% left, 40% right, the left tank gets lower than 1/4 before the right tank. Should I not take off when both are less than 1/4 or I'm OK if just one is less than 1/4? Clearly I'm overthinking the issue

But I'm agreeing with you. The manual says not recommended, and so is not prohibited. The gauge is a more strongly worded recommendation. I do have a fuel flow and total remaining in my engine monitor. Someday I'll replace the current gauges with electronic. If only to make them easier to see without stretching my neck around.

Jim…there is no “POH” for the 170. You are likely referring to the “Owners Manual” …published by the Cessna Marketing Dept…having good and conservative advice…but that is what it is. The Regulatory document is the Airplane Flight Manual (AFM).

However, certainly a conservative approach is admirable…I just wouldn’t want anyone to be fearful of a “Go-Around” when it is warranted because of a Marketing-brochure or an advisory-placard. You have 37 gals of useable fuel onboard a B model and that means it’s available, by definition —“under the most adverse fuel feed condition for all intended operations and flight maneuvers.”