38.5gal tanks on Arrow 2

hindsight2020

hindsight2020

Final Approach
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hindsight2020
It's daydream Friday. Did a search on the defunct piper owner site and found little info. Looking to research the possibility of installing the Arrow III tanks on a arrow II. From my cursory reading, the work would involve moving one rib to accomodate the wider tank, and trimming the skin. Probably new fuel senders and put 38.5 gal gages in the cockpit.

Is this something a 337 form/process would cover? What kind of shop would be best to undertake that modification work? How much would the tanks run me (salvage or otherwise), assuming I can get my 25 gal tanks exchanged for credit?

As always, when it came to engines, the answer was always to sell the airplane and buy one with the thing you want installed. But I've been looking at the prices of arrow IIIs and without a 430W and $5AMUs worth of K2U mods (installed) they still want in excess of 30K+ from my original purchase price on the II. There's no way two tanks and some sheet metal work would come close to that delta. I don't care about resale. I just want to be the father of the Piper Arrow II 1/2!!! :goofy:

As to why consider such a thing? Because I want to fly 1000NM non-stop and I don't want to re-start the new-to-me kabuki with another airplane that's not equipped the way mine already is. Additionally, the wings are only partially painted so it's PERFECT to fiddle with them without incurring additional paint costs. :yes:.

I must say I've yet seen an Arrow modded this way, so trying to see what's involved on the paperwork side.
 
The Arrow II and the Arrow III have totally different wings. The II has the constant chord (Hershey Bar) wing and is a couple feet shorter than the III which has the tapered wing.

Although the fuel tanks look similar I am not certain that they are.
 
You would have to hire a DER to do the engineering. Just buy a new Bonanza for the same cost.
 
Even if it was to be able to slide into the same hole. You'd have trouble getting the screws to start, as the holes were hand drilled, and no two tanks have the same hole pattern.
Have you looked into tip tanks?
 
tmyers said:
The Arrow II and the Arrow III have totally different wings. The II has the constant chord (Hershey Bar) wing and is a couple feet shorter than the III which has the tapered wing.

Although the fuel tanks look similar I am not certain that they are.
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My understanding of the cherokee wing is that onboard of the the rib station where the semi-tapered wing begins the aforementioned taper, it is the exact same wing and airfoil as the hershey bar. Fuel tanks are located within said stations.

kgruber said:
You would have to hire a DER to do the engineering. Just buy a new Bonanza for the same cost.
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Why? Is a 337 insufficient for such a mod? Guess i'll have to wait until the part 23 re-write is official.

bluerooster said:
Even if it was to be able to slide into the same hole. You'd have trouble getting the screws to start, as the holes were hand drilled, and no two tanks have the same hole pattern.
Have you looked into tip tanks?
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Haven't looked into those. Do they make em? All I've seen have been those cumbersome ferry bladders that are temporary, but that's a lot of fume inhalation in the cockpit and I want something permanent that doesn't compromise my cabin. If you have a link to tip tanks that would be awesome.
 
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Not aware of tip tanks for the Cherokee line. Next time I am at the airport I will take some measurements of the tanks on my III and let you know what they are.
 
hindsight2020 said:
Haven't looked into those. Do they make em? All I've seen have been those cumbersome ferry bladders that are temporary, but that's a lot of fume inhalation in the cockpit and I want something permanent that doesn't compromise my cabin. If you have a link to tip tanks that would be awesome.
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The 235s have them. So I suspect that there are some available somewhere. I haven't done any research, as 50 gal. total is more fuel than I can burn before I need to "drain the sumps".
 
bluerooster said:
The 235s have them. So I suspect that there are some available somewhere. I haven't done any research, as 50 gal. total is more fuel than I can burn before I need to "drain the sumps".
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They do? What capacity?
 
Pilawt said:
All Cherokee 235s and Cherokee Sixes (pre-1979) have tanks in the wingtips that hold 17 gallons each. But I've never heard of them being retrofitted on other models.
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Yeah I was thinking Dakota, they have the same setup as the Arrow III. I'll probably ask my A/P buddy and see what I can come up with. If it truly is a paperwork brick wall I may have to wait for the primary non-commercial thing to become reality. Oh well, it's still on the wishlist of things to do. My primary mission is not going to exceed the useful load of the Arrow any time soon and the long range bucket list type trips would be accomplished solo or with spouse only. For now the 50 gal capacity works for family trips. I'll def update the fellow POAers if I ever manage to undertake such a project.
 
hindsight2020 said:
It's daydream Friday. Did a search on the defunct piper owner site and found little info. Looking to research the possibility of installing the Arrow III tanks on a arrow II. From my cursory reading, the work would involve moving one rib to accomodate the wider tank, and trimming the skin. Probably new fuel senders and put 38.5 gal gages in the cockpit.

Is this something a 337 form/process would cover? What kind of shop would be best to undertake that modification work? How much would the tanks run me (salvage or otherwise), assuming I can get my 25 gal tanks exchanged for credit?

As always, when it came to engines, the answer was always to sell the airplane and buy one with the thing you want installed. But I've been looking at the prices of arrow IIIs and without a 430W and $5AMUs worth of K2U mods (installed) they still want in excess of 30K+ from my original purchase price on the II. There's no way two tanks and some sheet metal work would come close to that delta. I don't care about resale. I just want to be the father of the Piper Arrow II 1/2!!! :goofy:

As to why consider such a thing? Because I want to fly 1000NM non-stop and I don't want to re-start the new-to-me kabuki with another airplane that's not equipped the way mine already is. Additionally, the wings are only partially painted so it's PERFECT to fiddle with them without incurring additional paint costs. :yes:.

I must say I've yet seen an Arrow modded this way, so trying to see what's involved on the paperwork side.
Click to expand...

Run away.
 
1000 NM non-stop, in an Arrow??:mad2::mad2: that's a long flight in a Citation! :D @140 knots, no wind, that's over 7 hours!
If it's a one time going to Europe trip, get a ferry tank, if it's a regular trip, get a faster plane, much faster! :D
 
If I am light I will put the 72 gallons in my Arrow. I would never want to fly that long but it sure would come in handy if I needed to find better weather. My normal operations are to out it at the tabs which is 50 gallons.
 
N747JB said:
1000 NM non-stop, in an Arrow??:mad2::mad2: that's a long flight in a Citation! :D @140 knots, no wind, that's over 7 hours!
If it's a one time going to Europe trip, get a ferry tank, if it's a regular trip, get a faster plane, much faster! :D
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Yeah it's an occasional trip kinda thing. I wouldn't make a habit out of attempting such a thing on a regular basis. Also, the mileage on the trip is actually 875NM, which i round up to 900NM. An Arrow III @ 65% power can do it in 7.3 hours with 45 minute IFR reserves , with a 10knot headwind already accounted for. A mooney J can do it on stock tanks with IFR reserve. An F would need the extended tanks. If they weren't so cotton-picking uncomfortable to sit in I would have gone the F route with the 100 gal extension, but that's water under the bridge. Same for the Arrow III, I didn't think the extra fuel capacity was worth the listed price delta, plus they're rare to find on the market compared to arrow IIs.

tmyers said:
If I am light I will put the 72 gallons in my Arrow. I would never want to fly that long but it sure would come in handy if I needed to find better weather. My normal operations are to out it at the tabs which is 50 gallons.
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Yep, this would be my operating norm as well. 50 gal for the short hops with the fam, full gas for tanking to expensive places or bucket list solo type trips. I'm still in a life stage where my family size will not exceed useful load for decades, if ever. Springing up to a Lance would not net me any advantage (even if I could afford the purchase price, which I can't); it would just do my mission much much less efficiently.

I'm just gonna ask the question. The worst the FAA can say is no. :lol:

ETA: Spoke with my AP buddy and he seems to agree with yall regarding the economic non-starter nature of going the 337 field approval route. Looks like there never was any interest towards increasing fuel capacity at the stc level for the old cherokees. The 12`ferry tank thing looks like a mess, I want something permanent.

A mooney J or arrow iii are lateral moves not worth the hassle or expense for 5% of my mission. Looks like Im staying short legged for a long while. Oh well, it was a nice daydream. Thanks for all the inputs fellas! It's nice to spend figment money sometimes.:D
 
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Putting the design and engineering aspects aside, have you ever driven nonstop in a car for 7 hours without moving from the driver's seat? Have you ever sat on an airliner as a passenger, for that matter, without getting up to even walk to the bathroom or just stretch the legs for 7 hours straight?

It seems that sitting in the confines of a piston single for that long outweighs any benefits to being able to make the nonstop trip.
 
I did 6 hours in the Comanche. If I had an autopilot and more fuel I could have went further. It wasn't the sitting that was the issue. It was trying to hold attitude/altitude, hold something to pee into and hold my hangdang. I only have two hands.
 
I'll call the fsdo next week and talk to the mx inspector on duty as see what they say. If he tells me to go hire a DER to give me the run around (I'm an aerospace engineer; I don't need a rent-seeking middle man to try to charge me for what I already know), then I'll archive my engineering work and postpone the project for a day where primary non-commercial is law. Either way, I'll be sure and update you fine POA folks on my little eater egg hunt :D


deltaindia said:
Putting the design and engineering aspects aside, have you ever driven nonstop in a car for 7 hours without moving from the driver's seat? Have you ever sat on an airliner as a passenger, for that matter, without getting up to even walk to the bathroom or just stretch the legs for 7 hours straight?

It seems that sitting in the confines of a piston single for that long outweighs any benefits to being able to make the nonstop trip.
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You must have me confused, I don't fly a mooney. :D I shuffle plenty in my good ol' Arrow II. At least as an faa adult I can say that.
 
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