The International Cessna 170 Association

bigrenna wrote:

gahorn wrote: Well, ....just to be conversational ...

I believe you've likely made an error in calculating your 170 fuel burn at 5.5 gph. I suspect it's more like 7.5 gph. I also suspect you meant the 180 speed is 145 KTs...instead of mph.

You can be as "controversial" as you want George. (Whats new.) But my experience is my experience.

No reason to feel defensive. OR sarcastic. I was only showing some interesting comparisons.
(and if you re-read it.....you also misquoted me....the word is CONVERSATIONAL)

And Tim I completely agree with the comparative analysis of fuel load versus mission payload.
I was thinking of the occasions when I depart from base ops, planning to destination and return
without uploading additional (expensive) fuel.

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lagunitas should be easier to get for you east coasters soon. Opening brewery in Chicago.

I loveIPA! I just had a few pints of Ranger (New Belgium brew). I love the banter, all in good fun.

The best mod is a 180hp engine. It has more poke than a pointed stick, parts can be purchased at "nearly" corner lolly store and its a robust engine. However I have learned that Cessna produced a turbine version in the 50,s for research into blown flaps etc,etc. My question is what was the performance of this aircraft? I have recently flown a Birddog with a Allison 250 B17b gas turbine. What a hoot. We will not discuss fuel consumption. So I am now wondering how a 170 would go with a Allison up the front.

ghostflyer wrote:... So I am now wondering how a 170 would go with a Allison up the front.

Not very far.

There's a Seabee at our field fitted with a PT-6, sorry don't know the model but the fuel burn is impressive. The number, I forget the exact figure but somewhere in the mid thirties. So probably the best mod has to be placed in context with cost and performance of all possible missions.
Mods that reduce weight are likely to pay back more per aircraft usage. In my aircraft's case, the factory had it right again . My (both of our) empty weight (s) have been steadily increasing with time.

The 600-750 shp PT-6 engines operate at cruise around 270 pph which equates to about 40 gph of Jet-A. Their takeoff fuel flows are around 350-plus. Economy cruise is about 230 pph/35 gph. The smaller/older -20 engines such as used in many conversions of old recips only make about 500 shp and burn about 25% less.

My 170B gained about 100 lbs since it left the factory and was restored. Although not painted, it has full interior poliamide primer, which I'm told is quite heavy, and helps explain it's aft C.G. (Scales showed 703-L, 720-R, 149-T with full fuel/oil. Subtracting 222 lbs of fuel leaves 1352 Operating Weight, to which must be added payload for flight.)
Many operators forget that their calculated E.W. also subtracted unuseable fuel/oil (42.25 lbs) and so they likely operate about that much overweight when they think they are at gross. My E.W. is 1303.75 lbs.
If the math is correct, it appears my E.W. C.G. is at 55578 MOM/ 42.63 ARM. ....which makes it dang near impossible to ever get my airplane into the Utility Category (and another reason besides unnecessary stress that I've never spun it.)

So I guess wingnut is correct.... that poliamide is heavy.

Good thing my exterior stripes are RED.

Anyway, with a EM7655 prop it uses lots of runway and has a low ROC when it's loaded down on a hot day.
I have an EM7652 prop I intend to install for flight testing before this summers' vacation to Bardstown, and I hope to
document the differences carefully in an article. I'm waiting for a pretty day convenient for a helper to take measurements and times on level pavement. I expect to gain TO/Climb at the penalty of cruise and fuel-burn.

The thing everyone wants to know is exactly what effects a particular prop-pitch change will make, and that's a difficult thing to nail-down because of other variables, including individual prop-condition and engine performance. The prop I'm planning to use, measures full-length and has only 200 hrs and no visible defects on it since ovhl. My engine is mid-time at 900 hrs and runing good with fair compressions, so I'm hoping the results will prove useful.

The bottom line is that I suspect the best/cost-effective mod to make to a standard airplane for better short-field performance (STOL may be a misnomer in these aircraft) will be the propeller, coupled with a serious weight-reduction program. Cruise performance will be compromised.
You want better cruise and lower fuel burn? Give up on the shortest runways.

The turbine 170 wasn't actually powered by a turbine but had a turbine installed IN THE CABIN to provide air to be blown over the wing for boundary layer control as described below;

Model 309/319--Cessna participated in Boundary Layer Control (BLC) research from 1951 to 1955 with the U.S. Navy and Wichita University using a stock 170A modified to house a small gas turbine in the fuselage which blew air over the wing (1951). The 309A, first flown in February 1952, used an engine-driven electric generator to operate large fans in the wings to generate the air; the 309B of 1953 and 309C in 1954 used dry chemicals that generated airflow across the wings and flaps.

Another follow-on, the 319-A of 1953, had larger, more powerful flaps. With 225 hp Continental engine and BLC, the airplane had a stall speed of 32 mph. It could take off in 190 ft, land in 160 ft and make it in over a 50-ft obstacle in just 450 ft. As a research vehicle, the 309/319 was a success, but its commercial application was questionable--or as a Cessna test pilot wrote on a report after his first flight, "All in all, a rather nasty little monster!"

ghostflyer wrote:So I am now wondering how a 170 would go with a Allison up the front.

The Italian SM-1019 (turbine bird dog) with the 317hp Allison 250-B15 goes 125mph indicated at 18.5gph but it also has four 21gal fuel tanks for four hours range with an automatic Rube Goldberg fuel management system that actually works pretty well.

I can't see the 170 doing much better than 140mph indicated at 18.5gph but climb rate would most likely be over 2000fpm as long as you want. SM-1019 takeoff distance is pretty impressive at around 450' but is still no Super Cub and the spool-up time of the engine is no advantage in a bush flying role where you frequently need instant power. But as far as cool is concerned, it's hard to beat the Turbine Bird Dog.

Soloy put an Allison 250 in a C-185 and did a lot of testing back in the 1980s or 1990s with the intention of an STC which was never completed. If I remember correctly, the thinking was, the market was not there to justify it.

My mechanic in Anchorage who knows SM-1019s fairly well says the firewall-forward of the SM-1019 will bolt right onto a C-180. I would like to try that.

Not sure what is acceptable so set me straight if this is not. Also not sure if I should start a new thread to ask this questions. I tried to google it and look on this forum but didn't see anything conclusive. What is the Wing X product mentioned earlier in this discussion? Does anyone know if Vortex Generators are even being looked at for the 170's. From what I could find they are not but made no calls.

Maybe I haven't read enough on this stuff but never heard of that strip everything out of the plane you can talk. Maybe I need to reconsider what I am looking for an a plane. Maybe I can't have my fixed up pretty interior and a STOL plane as well in my price range. If I spend $35K on a base 170B it will probably always be base because I don't think I could ever in my lifetime (what's left of it anyway) pay for the prop and STOL kit much less an engine. Is the $45k a realistic number to go from a the stock 145 to the 180 engine?

Thanks,
Justin

backcountrypilots.org has some great info on stol kits and VG's the consenses was the VG's weren't worth the investment and destroy wing covers. the sportsman stol was highly praised,the horton stol was not.
I see alot of 170B with 145hp with stol kits already on...but i haven't heard a price for a conversion yet. i too would want a 170B with a 180hp and stol kit on some bushwheels...humm mmm fun.

Engine conversion cost depends on WAY too many factors to give a ballpark.
Are you able to do the work yourself or will you have to pay a shop?
Are you using a decent mid-time motor or do you plan to buy factory new?
The same with most of the other parts too. Serviceable or new?

The STC kit is probably the only constant in the equation unless you can get a field approval and make your own mount.

So, you can guess on anywhere between $25 to $85K for a conversion

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