Hello All,

As the topic says,... "Is an early C175 straight tail with an STC'd 0-470 worth doing?
It turns out I have run across a project airframe that the guy wants to sell and it includes the STC to install an 0-470.
No motor though, but possibly a constant speed prop in the deal. I'll take a look at the whole thing tomorrow and report what's there.

The airframe is advertised for under $9k. That, and other factors yet unknown will determine if the project is worth the time and effort.

What I'm looking for is all the usual (and great) comments/advise ranging from: "Those who have done it before", -to- "I knew a friend of a 2nd cousin who seen one of em fly over one day".

If this thing is worth doing it seems it would compare favorably to an early C182 with slightly less gross T/O weight.
To look at it another way, it may end up being 'more plane per dollar' if cost can be kept inline. But thats a huge unknown at this point.

Cost can also be offset in that I have the basic skills to do most of the work and have an A&P/IA who will keep me advised along the way.

OK... let it rip with the.... "I wouldn't do it again if you paid me to!"

I don't have any experience with either but here is my 2 cents worth... I would opt for a straight tail 182, you can pick them up for under 40k. It has a trimable stab and the 175 does not, so it will be a faster airplane with the same fuel burn. Gross weight is 100lbs more on the 182 plus you have the option of increasing that by 400lbs with Wing-X extensions (STC not available for 175s). Also the 182 has larger tanks than the 175 did. By the time you finish your project 175 you'll probably have more in it than what you could have bought a flying 182 for.

I did one of these conversions for a customer.... They fly ok... Climb like a homesick angel... But, I would be more inclines to do an 0-360 conversion with a constant speed than the 0-470.....

Her are my reasons.... Engine weight, the 470 is nose heavy... The STC requires installing a chunk of lead on the rear tail bulkhead above the elevator and that brings the CG right at the forward limits.... The STC does increase the gross weight of the airplane though.... As mentioned the trim is not ideal and I was told by the owner that he ran out of trim in certain instances.... The 470 burns a lot more fuel....

The 360 engine is lighter than the original GO-300... With the constant speed prop the weight is just about the same with a better performing engine and prop combination.... With the 175's bigger tanks it makes a nice cross country machine over a 360 converted 172 of the same years....CG is not a factor with the 360 and it trims well.... Less fuel burn over the 470 and possibly even the GO-300, so more range....

Ultimately, a 175 with an 0-360 lightly pumped up converted to a tail dragger and a MT prop would be a sweet airplane....

Brian

I flew a 175 with 470 and as Brian says they are boasters on t/o and climb.....BUT, they need more gas unless you're not going far, they are far forward CG, etc. not a well balanced plane, but.....

The 470 is a great engine, but this isn't the right platform for that engine, in my opinion.

I'd second Brian's suggestions above.

MTV

I have recently looked at two different 175's with this conversion done to them. I forget what the asking price is/was but I think one was around $40K. This particular plane in located in Mn and looked like a decent aircraft. It was at Oshkosj that I originally saw it with a For Sale sign.
If I can find the picture I took of the sign I will post the info. You can at least call the guy and pose any questions you might have.

Do you really want your widow to have to deal with an unfinished project

+2 on ix-nay on the 175. Not having the trimmable tail makes it nowhere near as nice to fly as the 180/182's are.

There was a beautiful 175 conversion at JC this year, equipped with an O-360. It was cool looking, and probably very capable, but it is no substitute for a 180.

That's a project I'd tackle only if the project core was extremely inexpensive. Since they're a bastard when you're done, the resale is always a little low.

I knew I had a couple of pictures of the one I did.... Not very detailed but you the installation is there... Date on the photo is 2003 so it's been a while....





Forgot to mention that there was a second 175 built by a local guy here that he did the 0-470 and Tail Wheel conversion on.... That aircraft needed twice the weight in lead on the tail to get the CG balanced out.

Brian.

Not too bad combo except for fuel usage and having to put weight in tail. They had one 175 with 0-470 up front to tow banners - light blue that ran out of fuel and tried to land in Dodger Stadium parking lot ??? . If I had 175 without engine I'd opt for 0-360 or io-360 ( continital ) - or maybe Franklin 220 . 175 has smaller tail than 182 of same vintage - fuselage is close - wing is close to straighttail 182 .

Found the ad:

1959 175 Tail Wheel conversion with new paint, interior, and glass w O-470-R and CS prop
3000TT 800SMOH 200STOH
King KTN 89B GPS
KX-155
dual MX 11 Digital Flip Flop
AM/FM CD player
KT-76A Transponder w/Mode C
Four Place Intercom
CHT and Ex Temp
Wheel Pants
Stobes
Shoulder Harness
Float Kit available
And more...
$42,500
Dave 763-228-6533

I have a photo of the plane I can forward if interested. It was a nice looking plane from what I remember and think it would be very hard for a guy could build one for the asking price.

I had a $10,000 C-175 with the GO-300. Only got 400 hours on the engine. Piston rod came loose on takeoff from Santa Fe and I landed at Santa Domingo Pueblo. Put another engine in it and sold it. I really liked the airplane, however. I didn't keep scraping my bald head on the bottom of the wing, like with other Cessnas. You get about a foot less ground effect energy on takeoff. These boys are right about conversions never flying as well as the originals. Trim and balance are really important if you spend a thousand hours in them every year.

Don't forget, there's an AD on the 4 engine mounts-the part inside the airframe that the steel tube engine mount in the engine compartment attaches to, just behind the firewall, Cessna wants $1,000. for new mounts last time I checked, more every time I check, easy to do when engine off anyway. Apparently 175 streamline rudder/fin have marginal authority, straight tail/fin (like a 180) are better. Ez-flap working on TD STC, not have to redo floor, very good workmanship, Al gear. Waiting on Feds. Don't bug him, he will announce here when timely.

As to the 470 idea, I think a Lyc. or Cont. 360 w/ CS prop. is a much better package, Franklin 180 or 220 also good. One problem w/ STC's that are not very recent; prop makers, obsolete props every few years, making parts a problem. For a modern prop not spec'd in an STC, out of production, new engine-airframe-prop vibration analysis must be complied with, very costly.

I have heard that stock stabilizer/elevator authority makes it hard to do a full stall landing w/ flaps extended. Later 172 stabilizer/elevator w/ slightly longer span, after about '63, solve this problem. No known STC.

I do like my '59 C175 on floats with the 0470. Yes, it's heavier with the big engine and 11# of lead in the rear bulkhead. But it performs very well, cruises 110 mph on aqua 2400 floats, which are more than adequate, and I have no problem with the controls (square tail). With me solo I land with a little power and leave it on for a bit after touchdown to avoid the forward lurch it might want to do dead stick. With passengers or my big dog in the rear it's never a problem. My experience is that an empty 182 on wheels is also nose heavy solo.

When the engine mount stc came out my mechanic found one, the upper right, that had been deformed, and replaced it. I like the bigger tanks and beefier wings, and added the sportsman STOL. I pull it out of the water at 50 with the nice big manual flaps, then fly low, bleeding them back up until it's clean and climbing at 80 mph, then start pulling back the power and rpm. The engine book recommends cruising at 23/23, so that's what I do. It uses about 11 gph so my max range is about 400 miles. My engine is mid time and I fly about 30-40 hours/year. I live in Fairbanks, Alaska, so I have no reason to take it off floats. It goes into "suspended animation" from October to mid May.

The gross weight is 2550 and never fails to get up and fly. A major advantage of most 175's is the low total time on the airframe, it's rare to see over 3000 hours.

Finally, I have flown the 170B with the 180 hp Lyc and found similar performance on Edo 2000's, which is a bit under-floated, especially trying to turn around in wind. I have had to shut down and "sail" back to takeoff length, which I rarely need to do in the 175. The 0470 is a smoother running engine than the high compression Lyc 180 and can qualify for an unleaded auto fuel stc.

All thing said, I am very happy with the airplane, and probably use it until retiring from flying.