1948 C170 - Pre-purchase guidance requested

[Romeo Tango]

I've searched the entire website (outstanding, thank you), and couldn't find explicit responses to some questions - with your indulgence I seek the collective wisdom.

I've got my eye on an 1948 ragwing C170. It's been refinished inside and out, and it's a gorgeous airplane. We'll get the mechanic on the inside of the engine, wings and fuselage to make sure all parts are in order. This is my first airplane purchase, so I have a few rookie questions.

My specific inquiries:

1) I'll be based at sea level in Northern California - with most trips to other coastal towns, and sometimes up into the Sierra Nevada. Is the C170 with 145hp an acceptable machine to take two adults and a picnic basket to Lake Tahoe (field elevation ~6000', 6000'+ runway)? I'd carefully plan for arrival time in the cool of the early morning.

2) Are shoulder harnesses a *you must have* item? I've never flown without them, and felt just a bit naked not having one on the test flight.

3) There was a bit more oil than I'd expect thrown inside the engine compartment after a 30 minute flight. It appears to have come from around the generator - which I'd want to replace with an alternator anyway. Any "gotchas" or specific things to point my A&P toward?

4) I plan to replace the generator with an alternator. This plane will eventually be equipped for light IFR, and I'd rather have an alternator. I've seen pro and cons on this on the discussion threads and invite any additional commentary.

5) I want to replace the fuses with circuitbreakers. I think this may be required when you replace the alternator. Does this require any special authorization or just proper documentation of modification?

6) I'd add the PPonk gear stiffeners - that plus the Scott 3200A tailwheel seem to be a reasonable insurance policy and value-add to the airplane.

Thank you in advance for guidance. If I make the purchase, I'll absolutely be joining the TIC170A.

Richard

[Dave Clark]

Richard

Welcome to the site and hopefully the wonderful world of 170s!

1. It's not the arrival time it's the departure, right? Two reasonably sized adults, one light picnic basket, and light on fuel you'll probably be fine if the density altitude has not gone much over the field altitude. The 170 really doesn't like tha last couple of hundred pounds to gross weight with the stock engine especially. Two things you might do, get a performance chart for the 170, and maybe get a ride in one or an early 172 at Tahoe.

2. Shoulder harnesses are really nice when you have a sudden stoppage into something solid. There was a thread, maybe on the old site, about the legality and ways of getting inexpensive harness protection in the 170.

I'll leave the rest to others.

[flyguy]

1. In the thirty something years I have owned '93D it has never indicated anything less than willingness to carry the published payload at "msl". Density altitude will affect the 170 the same as any other airplane. As Dave suggested, your arrival at the destination is of less importance than when you try to depart. Density altitude really affects the take-off attempt much more than landing. Cool early morning departures are the most sucessful where one might encounter HDA situations.

2. Shoulder restraints are the last bastion of a poorly planned flight attempt. Catastrophic engine failure is the only reason to make an un-planned off-airport contact with material that generates sudden stops. Others may disagree, but IMHO the addition of shoulder restraints over conventional seat belts in an egg shell such as an aluminun fuselage gives little additional chance of survival in a real wreck. Most likey I am the only one on this forum who has actually been upside down in a 170 while it was still on the ground! In that encounter, a shoulder harness would not have made one whit of difference. My only physical injury* was a little bump on my head when I released my (not metal to metal) seat belt and gravity forced me down onto the cabin roof and the beanie on my cap dented my hard head! (*The injury to my ego was more severe!)

3. Several comments about generator oil seals are addressed in the post of the last few months. Another seal to look at is the tach drive seal. Cheap items to fix.

4. An alternator is a very nice addition but has some downsides. Most of our planes can get along very nicely with a 25 or 35 amp generator. Why spend a lot of money for something that will add the ( un-? ) needed amperage but also lacks the ability to excite itself into charging the battery if it is completely dead. You can hand prop (if only really necessary) and start an airplane engine without benefit of a battery, but a dead battery will remain as dead as a doornail if you have an alternator in the place of a generator.

5. The "Ponk" mod will assure "total" destruction of the gear box in the event of a incident that would damage the gear box anyway. The gear box parts in the aluminum fuselage are no stronger than their weakest part and those are not the castings inside the 'box'. OLE GAR

MTCW!

[Curtis Brown]

At overhaul I went with the 50 amp alternator. I did not have to replace fuses with circuit breakers. However, their are circuit breakers that are in use for the alternator. I really like the alternator and can now operate the landing light and transmit on the radio at the same time.

I have the Hooker harnass system and feel more safe with it. It does limit my reach at times. With a little loosening, I can reach the flaps and my radio on the far right side yet still feel that it is tight enough for protection. I usually sinch it down tightly at take off and landing.

I also use the safe-T-locks on the seat rails. Just do not trust the seat to stay in position.
Good Luck, join us in the club and let us know what you do.
Curtis

[GAHorn]

I've searched the entire website (outstanding, thank you), and couldn't find explicit responses to some questions - with your indulgence I seek the collective wisdom.

I've got my eye on an 1948 ragwing C170. It's been refinished inside and out, and it's a gorgeous airplane. We'll get the mechanic on the inside of the engine, wings and fuselage to make sure all parts are in order. This is my first airplane purchase, so I have a few rookie questions.

My specific inquiries:

1) I'll be based at sea level in Northern California - with most trips to other coastal towns, and sometimes up into the Sierra Nevada. Is the C170 with 145hp an acceptable machine to take two adults and a picnic basket to Lake Tahoe (field elevation ~6000', 6000'+ runway)? I'd carefully plan for arrival time in the cool of the early morning.

2) Are shoulder harnesses a *you must have* item? I've never flown without them, and felt just a bit naked not having one on the test flight.

3) There was a bit more oil than I'd expect thrown inside the engine compartment after a 30 minute flight. It appears to have come from around the generator - which I'd want to replace with an alternator anyway. Any "gotchas" or specific things to point my A&P toward?

4) I plan to replace the generator with an alternator. This plane will eventually be equipped for light IFR, and I'd rather have an alternator. I've seen pro and cons on this on the discussion threads and invite any additional commentary.

5) I want to replace the fuses with circuitbreakers. I think this may be required when you replace the alternator. Does this require any special authorization or just proper documentation of modification?

6) I'd add the PPonk gear stiffeners - that plus the Scott 3200A tailwheel seem to be a reasonable insurance policy and value-add to the airplane.

Thank you in advance for guidance. If I make the purchase, I'll absolutely be joining the TIC170A.

Richard

Well, just to maintain my image as a non-conforming antagonist I'll disagree with my Louisiana friend regarding the shoulder harness, and with all whom have so-far indicated that arrival is not the concern at Tahoe. An arrival anywhere should always take into consideration the last minute go-around, which I can assure you will be "interesting" at Tahoe. (For those not familiar, Lake Tahoe arrivals typically come in from over the lake, and departures frequently depart the same direction...into a dead-end hillside that, unless considerable climb capability exists, requires a 180-degree turn at high density alitudes (even in winter) with hillsides filling all the windows in the cockpit. (I've performed straight-out departures there, but it was in Hawker jets, and even then all occupants kept a keen interest in the terrain closure rates.)
A go-around decision in a 170 should be performed early, if some numb-nuts pulls out while you're on final there. A departure toward the lake should be considered every time.
The shoulder harness issue is also important, in my opinion. The FAA and the NTSB and virtually every other organization considers shoulder harnesses tops on the list of turning fatal accidents into minor incidents. You don't have to turn upside down to bury a yoke in your chest, or a knob in your fore-head. (I also suspect Ole Gar' has been upside down in the cockpit many times when the airplane was right-side up. Don't ask me why.)
The shoulder harnesses can be installed in a ragwing for as little as $175 each with kits from Wag Aero, Aircraft Spruce, etc.
The P-ponk upgrade is critiqued by some with the claim that the airplane is damaged more seriously when the modification fails to prevent damage. (Doh!) It's sort of like saying a condom doesn't prevent disease if you use it so violently that it breaks. (And trust me, Ole Gar' hasn't got a clue what I'm talking about!)
I like and recommend the P-ponk mod, if for no other reason than it will protect your airplane from serious damage should the single little bolt/nut that holds the inboard end of your spring gear should fail, you won't lose the airplane over it. (And if you crash so severely that the P-ponk mod is torn out, then I'm afraid you'd have lost the gear-box anyway,...but not because of the mod.)
I know a lot of folks believe alternators are somehow better than generators, but only in one regard,....weight vs amps. Alternators became "hot" items when radio equipment advances required huge amperage increases. Two decades ago, to get better radios you had to add an ADF,a Transponder, an encoder, a DME, a Loran, a Glide-slope receiver, (or TWO of them!) and maybe even a VOR/DME-based RNAV unit. On top of that, many of the older radios had a heavy power-supply mounted in the tail somewhere that weighed more than the panel unit! Weight became a problem, and amperage-supply became a problem with generators.
But these days, with surface-technology avionics, you can do away with all that with a simple WAAS enabled GPS/COM and a transponder/encoder.
Not only can you do everything the older stuff did with about 30 lbs less weight, you can do it with less than 10 amps instead of 40!
A fully equipped IFR capable 170 should be happy with a 35 amp generator, and the owner will enjoy all the thrill of living in durable obsolescence. In any case, a failed alternator will cost you $500 and a failed gen only $175. The electricity is the same, just cheaper and easier to troubleshoot with a gen. and meanwhile you've saved $750-$1000 you didn't have to spend on an STC'd alt. that has limited repair facilities (unless you go with the even more expensive Cessna route.) My 2 cents.
Replacing fuses with C.B.'s is a good, but expensive mod, that is NOT req'd by the alternator upgrade. (It's easier to reset a C.B. than it is to find a fuse in the dark, but caution, ...only reset a C.B. or replace a fuse in flight if you KNOW you've isolated the problem. Don't do it more than once, in flight, unless you've gotten the offending appliance shut down.) It requires a Form 337 with Block 3 approval (field approval.) Your membership in TIC170A will more than pay for itself with the copies of previously approved paperwork you can obtain from headquarters@cessna170.org regarding such mods.

So, you're looking at a ragwing? Be certain it's fuel pump and the correct checkvalve are installed. And look for cracks in the rear bulkhead below the horizontal/vertical and especially at the tailwheel mounting bracket. Also, look at the wing attach mounting blocks within the carry-through spar attach's for corrosion.

[n3437d]

Flying out of Carson City (where I am based) I frequently fly westward over the Sierra's and then again Eastward back to Carson, usually flying through the gaps or much higher if the wind is blowing (which it frequently does). Anyone who discredits arrival time as being less important than departure time will sooner or later experience a surprise. However I do understand the intent. All aspects of flight should be well thought out as each has one or more critical phases. I will mention a few pointers for you to think about. Number one, the Tahoe tower is manned, usually after 9am. It is a somewhat tricky airport (due to illusion). With the Lake Breeze landing to the North is frequently the trend. You come in over high ground with the downwind to base being the highest and then the runway is a downhill grade. There is plently of room both width and length but be aware of this. The good part is that there is generally not much traffic at all. Now going up to the North end of the Lake near and around Truckee you have a lot of traffic of all mixes. Numerous glider activity and high speed approaches and departures from the "jet-setters."CTAF does a great job and usually responds to all calls. The next and what I would consider very important when flying around the Sierra's (or any mountainous regions), BE AWARE of the LEE side of the mountain as the "down" is many times more powerful than an 0300. There is frequent mountain wave and again the "sink" or downside of the lift can exceed 2000fpm. Be careful of the venturi effect when flying close to the gaps crossing mountains.
And last, the shoulder harness. I just installed a pair in my plane. I love the added security when it gets "bouncy."

My 2 cents worth

[zero.one.victor]

Regarding pre-buy items on a ragwing,it's a good idea to punch test the fabric. Like George said,make sure it's got the stock engine-driven fuel pump installed--necesary for airworthiness. The check-valve is located
near the carb where the fuel lines "tee",make sure the arrow on the check-valve case points toward the carb. Otherwise,check for everything you would on any other Cessna:AD compliance,corrosion,damage,etc. I wouldn't worry about damage history unless it's fairly recent--if it's old history & the plane has sufficient hours since repair,it's probably not a worry.But check the repair work anyway.
My ragwing was modified by previous owner(s) with 180 gear legs,Ponk kit,60-amp alternator,& circuit breakers. While I'm not unhappy with any of these mods,I don't know that I would have spent the time & money. It does NOT have shoulder harnesses,which I do think are a useful mod. If ya run into a ditch/hangar/whatever,or nose it over,harnesses might make the difference between being embarassed & having a broken face. Shoulder harnesses & tail-pull handles are on my list of things to get--of course,they have been for several years now! One of these days.......
I was originally looking for a B model,I just bought the ragwing (cuz it was too good a deal to pass up!) to tide me over til I found a worthy B. That was 6 years ago......

Eric

[1948ragwing]

1) I'll be based at sea level in Northern California - with most trips to other coastal towns, and sometimes up into the Sierra Nevada. Is the C170 with 145hp an acceptable machine to take two adults and a picnic basket to Lake Tahoe (field elevation ~6000', 6000'+ runway)? I'd carefully plan for arrival time in the cool of the early morning.

I was based out of Salt Lake City (U42) for a few years, where the field elevation was 4603' (density altitude in summer over 10000). We used to go camping in Idaho at a few high altitude strips and flew in to EVW at 7163'. The airplane will carry all that you need, just make sure the pilot is up to the task in case of a go/no-go situation.

2) Are shoulder harnesses a *you must have* item? I've never flown without them, and felt just a bit naked not having one on the test flight.

I have Hookers. Definately not the $$$ for inertial reel, but well worth it.

4) I plan to replace the generator with an alternator. This plane will eventually be equipped for light IFR, and I'd rather have an alternator. I've seen pro and cons on this on the discussion threads and invite any additional commentary.

My ragwing had an alternator installed when I purchased it. If I was buying a plane with a generator in it, I would leave it alone.

5) I want to replace the fuses with circuit breakers. I think this may be required when you replace the alternator. Does this require any special authorization or just proper documentation of modification?

I still have fuses in my bird. Circuit breakers would be nice if a fuse blew, but there was a reason it blew!

6) I'd add the PPonk gear stiffeners - that plus the Scott 3200A tailwheel seem to be a reasonable insurance policy and value-add to the airplane.

My airplane has the P.Ponk mods installed, plus C-180 gear and the Scott 3200.

[Romeo Tango]

All, this is extremely helpful guidance, thank you. I am taking my mechanic to go in deep this weekend and will report back. Hopefully with an enrollment in the association.

I will definitely put in the shoulder harness system. Certainly as the "last resort" for a bad flight attempt - but more for in-flight safety and security (I have gotten into some character building Sierra turbulence that was enough to take off my headsets). The BAS system is appealing, but not at the price. Hooker will do just fine, thank you.

My jury is still out on the Alternator/Generator. I understand the appeal of the dead-battery/handprop option, but I also like the more continuous and efficient power from an alternator. At some point the IFR stuff will wander onto the panel and that's probably a good starting point amp-wise.

Eric - re: "stock engine-driven fuel pump" - is there an AD on this? I downloaded all the ADs I could find. Were these simply removed by some folks thinking gravity feed was sufficient? Or replaced with inferior units? And is there a specific marking for the correct checkvalve in the fuel line? I've ordered documentation but it may not arrive prior to the inspection this weekend.

Richard

[Mike Smith]

Richard,

I live in Grass Valley (elev. 3150') and flew my 170A to OSH this year over the Sierra's and the Rocky's into the high elevations of Wyoming and SD. If you plan ahead (look at the takeoff performance numbers) and keep the weight at least 200 pounds below max gross weight then you will see adequate performance from the 170 (but certianly not sterling performance). I regularly fly to Truckee and the whole Tahoe area. Touch and go's at Markleeville (south of Tahoe) and other places. During my high altitude and High Density altitude takeoff's I always do a soft field takeoff technique (1 notch of flaps) and let the airplane "fly" when it's good and ready (I don't "pull" it off the ground). Once airborne I cut my climb rate and accelerate to about 85 or 90 mph for the climb. You will also have to take into consideration the terrain around you and always have a plan for a "way out". (i.e. where can I just circle or fly straight out to gain altitude) By doing these three things (T/O performance data, 1 notch of flaps on T/O, and having a plan for gaining altitude) you will address most of the issues you are concerned about for high altitude operations.

All that being said ... I usually do my Tahoe flying before noon and nearly always when the winds are less than 18 or 20 mph. More than 20 mph and it seems too much like work, and work is not why I'm flying my 170. : )

Cheers,
Mike

[zero.one.victor]

The fuel pump was standard equipment,and required by type certificate,on the 1948 (ragwing) 170 only. The only AD I'm aware of is to check the fuel screen inside the pump at every annual.
There are lots of ragwings operating (illegally) on 100% gravity fuel feed.I know a guy who owned one for 32 years,and he proudly told me that it never had a fuel pump on it in that time.99% of the time,that works great. The fuel pump is there for when the tank outlet is unported due to low fuel level combined with roll/pitch activity,the fuel can fail to flow thru the lines afterward due to the loss of siphon action.The high point in the lines is at the top of the front door post,this high point can be above the fuel level so once siphon action is lost gravity can fail to start it again. That's where the pump comes in.
I did a poor job of descrining the reason for the fuel pump,but that's beside the point. The point is that it's required by type certificate. In the past,a substitute (electric pump) arrangement has been OK'd by field approval.


Eric
Eric

[Romeo Tango]

Well, today I put my deposit down on a 1948 C170. Pending the prepurchase inspection, I'll be one of the gang. Very cool toy.

Richard

[Tom Downey]

Eric, did you know there is no failure criteria for Ceconite. So If it is Ceconite why punch it?

[zero.one.victor]

Tom,are you saying that Ceconite can not fail? Then you're right,why test it. However,I assume that it is not indestructible,and is therefore subject to failure. How does one detect a problem--wait til it is falling off the wings?

Eric

[Tom Downey]

Of course IF the Ceconite fails a cotton test it is bad, but keep in mind that the maule tester is made for cotton, not Dacron.

I have seen seen pretty poor ceconite, and it passed the cotton test.

It is usually the paint that FAILS.