props vs. crankshafts ?

[fairchild1934]

is there a centralized database place I can look up what props are good for which engines (crankshafts) ?????
thinking of the continental IO-470d for one---- wondering if there is a currently made fixed pitch prop----

thanks
Tim B.

[BradW1062]

Tim,

I don't think there is one centralized database with all of this on it - that would be way too simple . Besides, propeller installations are not only engine (crankshaft) specific - it depends more on the aircraft the engine is installed in, rather than just which engine it is.

The propeller manufacturers usually have application guides that list which prop was approved for which aircraft/engine combination, really aircraft specific there.

I have an old parts list from Continental that says the IO-470-D was used on the Aero Commander 200C, the Bellanca 260A, and the Cessna 310C thru H. So you probably should get the Type Certificate Data Sheets for these aircraft to see the specific props that were installed for that engine. But, I would guess that none of them are fixed-pitch.

This is the FAA web site for TCDS:

https://drs.faa.gov/browse/TCDSMODEL/doctypeDetails

It may be better (easier, faster, less frustrating) to just contact the prop manufacturers and tell them the application to see what they recommend. At this point for the Bearhawk, they may have seen it before. But a fixed-pitch prop for one of these O-470 engines is probably fairly rare. I would suspect maybe the Cessna L-19 Bird Dog or maybe a Cessna 188 AGwagon may be the only ones you will find. One of the aftermarket companies like Catto or Whirlwind may have something that will work.

Good luck,
Brad

[rv8bldr]

I would talk to Catto props (https://www.cattoprops.com/). Craig will custom make a prop for your specific engine/airframe/performance parameters. Compared to certified props, they are a LOT less expensive and perform great. He made the 3 blade prop I had on my RV-8 with an IO-360-A3B6D and it was awesome. With that prop the engine hit redline RPM at 192 kts, just 8 kts below VNE. Super smooth and great quality.

You can fill out a quote request on his website if you are curious.

Michel Roy has one on his Bearhawk (O-540).

[fairchild1934]

I really like the idea of a 3 blade composite. more ground clearance and way less weight for less torque reaction. I asked Cato but nothing for a fixed pitch. said he could make a cs one. have not asked whirlwind yet. looking like the io-470 I found may be just rust buckets and not worth consideration.
By "compatible" I was mostly thinking of prop harmonics vs. crank counterweight configuration. I expect the airframe consideration would be more of a squishy problem. i guess speed envelope related ?

i had thought of birdogs because they used the 470 series. Thought of ag planes but most of them used a 540 lyc
or a 520 cont. I THOUGHT i read on the net that early 310's used fixed pitch-- but I really cant see how that would have been possible----

i dont want to end up like the navion--- and buy a core that there is no prop made anymore for---- that would be bad...
:-)

[Battson]

This is a really tricky area to navigate.

I tried to contact manufacturers about which prop models were appropriate. They were generally unwilling to take the risk on an untested engine / airframe combination with a metal prop.

Matching a for metal prop to an engine (and airframe?) is a complex business, with serious consequences if it's done incorrectly and the prop or engine break in flight. I agree that composite is a good idea, it removes so much of the risk and manufacturers are more likely to assist you.

Sorry if this is already apparent - a fixed pitch prop is going to sacrifice a lot of performance from an IO-470 given the speed range of the Bearhawk. You probably already know that, just want to be ensure it's no surprise. If your crankshaft isn't drilled for the governor oil system, I get it.

If you are still choosing an engine at this stage, I would say that fitting an O-470 into the Bearhawk cowling is not necessarily as easy as fitting a Lycoming. Careful consideration is required if the engine has an external oil system, sumpless design, inverted oil systems etc. - I am not sure whether would be an easy fit. I know some people had to modify the firewall the make room. It all makes the build longer and harder to finish.

[fairchild1934]

Batt---
Yes-- I was only going to ask them about the harmonic aspects of which prop goes with which engine.

Not too worried about cowlings -- its just sheet metal -- can be formed into any shape we can dream ! :-)

Yes- I understand the Appairent disconnect of a fixed pitch on a big engine. But let me throw out the counter argument. (knowing ahead of time it may be a somewhat weak argument-)

260 hp is a lot. i would guess the plane will hit the max airspeed and the engine will have more power to give. So one could argue that all that huge power is more useful as increased climb rate and for clearing obstacles. The flip side would be that a low cruse or even high cruise- you would be turning more RPM than you need to ( with a climb fixed pitch prop ) . Then its like taking a cross country trip in a paper pawnee. :-)

Another reason I was thinking of fixed pitch was weight. The IO-470 is near the max weight bob recommends. So a fixed pitch would save weight on the nose.

I wonder if a Cato CS prop is way lighter than a conventional aluminum bladed one ? I would guess that most of the weight is in the aluminum blades. (?)
and not so much the hub. So maybe the Cato could be half the weight. Maybe longer overhaul/inspection time due to the wood composite being rather dampening of vibration. (where aluminum blades are the opposite- they are effectively like resonant tuning forks---)

The two IO-470's I was looking at appear to have a lot of external rust and aluminum corrosion--- so I am guessing that the chances of the crank being rust free is small. They look like they sat out on a ramp on a derelict plane for 20 years---- and they were 800 miles away so I couldn't scope them.

i might consider a cont. IO-360 --- as it looks like that would work moderately well on either a patrol or a 4 place at 210 HP. But they seem less plentiful as cores these days.

Tim

[zkelley2]

Batt---
Yes-- I was only going to ask them about the harmonic aspects of which prop goes with which engine.

Not too worried about cowlings -- its just sheet metal -- can be formed into any shape we can dream ! :-)

Yes- I understand the Appairent disconnect of a fixed pitch on a big engine. But let me throw out the counter argument. (knowing ahead of time it may be a somewhat weak argument-)

260 hp is a lot. i would guess the plane will hit the max airspeed and the engine will have more power to give. So one could argue that all that huge power is more useful as increased climb rate and for clearing obstacles. The flip side would be that a low cruse or even high cruise- you would be turning more RPM than you need to ( with a climb fixed pitch prop ) . Then its like taking a cross country trip in a paper pawnee. :-)

Another reason I was thinking of fixed pitch was weight. The IO-470 is near the max weight bob recommends. So a fixed pitch would save weight on the nose.

I wonder if a Cato CS prop is way lighter than a conventional aluminum bladed one ? I would guess that most of the weight is in the aluminum blades. (?)
and not so much the hub. So maybe the Cato could be half the weight. Maybe longer overhaul/inspection time due to the wood composite being rather dampening of vibration. (where aluminum blades are the opposite- they are effectively like resonant tuning forks---)

The two IO-470's I was looking at appear to have a lot of external rust and aluminum corrosion--- so I am guessing that the chances of the crank being rust free is small. They look like they sat out on a ramp on a derelict plane for 20 years---- and they were 800 miles away so I couldn't scope them.

i might consider a cont. IO-360 --- as it looks like that would work moderately well on either a patrol or a 4 place at 210 HP. But they seem less plentiful as cores these days.

Tim

Carbon constant speed props are about the same weight as fixed aluminum. Yes fixed carbon is lighter yet, but the performance loss is massive. The difference at takeoff or climb of these low reving engines at 2700rpm vs 2500 or even 2400rpms is quite large. 20+hp. There's no other way to easily increase the power of a conti/lyc then actually spinning full rated rpm. No other mod that isn't rather radical and not good for longevity of the engine(n2o, boost)will add 20+hp at takeoff and climb, where it's really needed.

Excess horsepower has everything to do with takeoff and climb. It has very little to do with cruise speed. You could bolt a 500HP pt6 to the front and the cruise speed of the same airplane wouldn't go up near what you think it would at lower altitudes. For a given amount of drag, power required goes up with the cube of speed. Lots more horsepower means lots more fuel burnt and very little time savings.

My bearhawk with 260hp cannot exceed it's Vne in level flight. Too much drag.

Ultimately if you want a faster airplane, you reduce drag. If you want an airplane to takeoff or climb faster, you increase horsepower.

[svyolo]

There is a great deal of wisdom in this thread. I can't disagree with any of it. From a market standpoint, there are lots more Conti's and matching CS props for a lower price in the US, as Cessna liked Conti in the old days. But you will spend more time sorting out the FWF. I don't disparage the prop manufacturers for their conservatism WRT harmonics.]

A composite CS prop costs more, but if you have a prop strike, you hopefully get to keep your crankshaft.

If you are planning on running around on big tires, a big part of me thinks I could be happy with a fixed pitch prop

In the end I bought a Bob 540, and Hartzell composite CS prop.

[nellie2110]

Just so happens I have a catto prop(also happens will be selling if this happens to peak anyones interest, haven’t listed it yet anywhere) this thread made me take a look at it to get some numbers. It is 84 in long with a 62 pitch with nickel leading edge. Craig Catto calculated a top speed of 160mph(we liked the speed calculation so the pitch was focused on t/o and climb)with the plane and engine setup(comp air 6 with io-470-m 240hp at 2600), the plan was to pponk it down the road and prop was still setup for 265 at 2700rpm. When a catto prop(at least when this one was made) is made for a continental it needs a hub spacer from saber. The prop with hardware was 19.64lbs(strap was 1.18lbs) add the spacer at 5lbs for a total of 24.64.

[zkelley2]

There is a great deal of wisdom in this thread. I can't disagree with any of it. From a market standpoint, there are lots more Conti's and matching CS props for a lower price in the US, as Cessna liked Conti in the old days. But you will spend more time sorting out the FWF. I don't disparage the prop manufacturers for their conservatism WRT harmonics.]

A composite CS prop costs more, but if you have a prop strike, you hopefully get to keep your crankshaft.

If you are planning on running around on big tires, a big part of me thinks I could be happy with a fixed pitch prop

In the end I bought a Bob 540, and Hartzell composite CS prop.

I think there's a lot of reasons used continentals are cheaper. The biggest is vans are designed around lycomings, so the demand for used is a lot higher. You can see it even in lycoming prices. If it goes on an RV it's worth more used. Look at Angle valve 540s vs parallel. The angle should cost more as a core or mid time, but they're a lot cheaper. The reason is the RV10.

Also, Continental wanted nothing to do with the experimental market forever. So no one designed for it. Which means there's also less aftermarket for it.
I'd also argue the lycoming is a better design. From the starter to the valves to the cylinder longevity to the weight. There is a reason continental makes lycoming clones now.

[Mark Moyle]

When I built my IO520 with the IO520D induction and fuel system, I started with a sandcast TSIO520WB. Stopped by Alaska Aircraft engines and went through their books to find the counterweight arrangement for my crankshaft to use a three blade prop McCauley prop off of a 207 that had a 310 hp turbo normalized IO520. I have zero RPM limitations up to 2700 rpm, 2850 for 5 minutes. Counter weight bushings and pins are fairly inexpensive.

[fairchild1934]

that catto is amazing that it only weighs 20 lbs. I have a couple of sensitch dm70's and they must be 45 lbs at least---
it would appear - on the surface --- that a parallel 540 and a 260 hp 047 have just about the same weight. so it appears they might be roughly similar in hp/weight. I have been nicely impressed with the smoothness of all the contys i have tried. mostly o-300's in 172's.

so far i am balancing doing the patrol with the o-320 I have ---- or doing the 4 seat B with an unknown engine I don't yet have. I keep thinking about the "bird in the hand worth 2 in the bush" thing. I prob don't have a known need for 4 seats. (at the moment) and I note that the narrower patrol has better climb and slower stall- all else being equal----

I think I will be scoping the 320 as soon as I get an articulated scope. It appears to have a new- never run top end. but I cant see the cam or crank till I pull off a jug. (got 12 qts of phillips 66 pickleing oil in it at the moment) It had no oil in it when i got it. Hope it didn't get any rust before I got it. its a 57 model o-320 without the bannana plates- so I guess it wouldn't be a good candidate for souping up.

I should be done with wing ribs soon and moving to thinking about spars. So that's the fork in the road I have to decide - patrol vs. b model. Kinds seems like the patrol is surging ahead. (in terms of saving $--- and using what I have all ready) its a budget build from the beginning !
What say YE ?

would yall say a 150 hp 320 would be "adequate" for a patrol ? (rather have a 200 hp 360)

( I will have to weigh my sensenitch props to see how much heavier they are than the catto)

Tim

[rodsmith]

I think a light weight Patrol would do fine with 150HP, especially if you aren't operating out of high DA airports regularly.