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possible engine question----

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  • possible engine question----

    I am talking to someone who has a (probably) run out (no prop strike) cont IO-470d for sale. Said it was running a year ago just before removed.
    My basic thumbnail search shows about260 hP, about 426 lbs dry. thats more hP than a 540. more or less the same weight.
    My question ---- i guess----- is this too heavy for a bearhawl 4 place or a patrol ? I guess the extra HP would just go into stupid high climb rate.
    I have read that this approximate weight allows for full load on the baggage area . But its about 100 lbs heavier than something like an o-360.....
    which it sounds like lands a bit slower due to the weight difference and maybe (?) elevator issues (?)

    Sounds like not too many have used this engine. Anyone know if the 470d can have a fixed pitch prop--- and if the modern companies produce one ?
    Am I right in thinking that each suffix would make a difference for props because of the different counterweight configurations ???

    With the engine being that heavy - might be nice to save some nose weight. I think I read where the first 310's had fixed pitch ( is that possible ?)
    and i think the pawnee had fixed pitch (but was that lyc. or cant. power-- )

    i can't find information on what is different on the d suffix model. Can find suffix info for Lycoming's but not cont.

    Any general thought on this whole big question mark ?

    Tim B.

  • #2
    260 hp is not more than a 540. Most 540 Bearhawks are 260.

    That is a VERY heavy engine for a Patrol.


    • #3
      Definitely not a Patrol engine. There are a few Bearhawks using the O-470, not sure the number but it is a viable option.


      • #4
        I'm running an io-470E on a 4-place A model. It works just fine. I'm not sure what the engine weighs. I had good intentions to weigh it before install but I never got around to it. The finished weight of the plane is 1550lbs so it couldn't have added too much. I've got aux tanks, comfortable seats, an extra baggage area aft of the main area... I'm running an aluminum CS prop so that adds a bunch of weight way out front.

        The engine is mounted further forward than an io-540 by about 5" so the CofG is definitely affected. I need ballast to fly alone but I can load it however I want and not have to worry about being too far aft.

        I wouldn't hesitate to do it again with the same engine. It's also super easy to work on with the extra space between the engine and firewall. I can change the oil, replace the alternator and starter and remove the exhaust system through the cowl doors with no issue.
        4-Place QB kit #111. First flight May 2022.
        IO-470 - 260hp


        • #5
          A guy had a couple of IO-470 selling cheap- but I just found out they are left had rotation engines. i guess that's why they are cheap.
          Would I guess that you would have to change the cam and every bearing in the engine and maybe all the cylinders to make it go right hand again ?
          or is there something else that makes it impossible ? i don't see any reason to start out with a left handed motor----


          • #6
            You could consider using a left rotating engine. It would probably have some effect on resale value, but wouldn't hurt performance any. Just reverse any offset in the vertical fin during the build.


            • #7
              I will contribute a little here, for what it’s worth -

              I have an O-470 that I am preparing to use on my “A model” QB. I have this engine for two reasons, really: 1) I have always liked the way 470’s and 520’s sound - the big-bore lope that they have when they are taxiing out turns my gears - hey, call me simple, and 2) it was cheap as dirt, about $2K, salvaged from an old abandoned Cessna 310 (O-470-M), and came as a full firewall-forward package with exhaust, baffles, all accessories, fuel-injection “carb” (PS-5C), and a CS Hartzell prop (HC-A2XF-2) and spinner. That was in 2012, and was a good deal at the time. My plan all along has been to convert it to either a low-compression 230hp carburetor -L, R, S model, or a 260hp IO-470-F or equivalent.

              Yes, I have heard all of the arguments on pros/cons of the Continentals vs Lycomings. And it really doesn’t matter to me, I simply chose to go with a “previously certified” engine and prop because I know enough of the engineering to know that I don’t want to go there with anything else. At least not for my peace of mind. And this one had a good price at the right time, most good Lycomings were more. For the weight argument, well I weighed my engine, in detail from the firewall forward package down to stripped bare, so I have the weights, and I can tell you there is little to no difference apples-to-apples between this and a Lycoming 540. I found it to be maybe 25#, depending on what you include. For instance, the Bendix PS-5C and the attaching manifold and brackets for my engine was about 10# - I don't know what a M-S MA-4-5 weighs, mounted right on the bottom of an O-540, so there's a small difference right there that's hard to account for. The published weights for the 540’s and 470's do not include starter and alternator, and that’s easily anywhere from 20-50# of a variation, so you have to keep that in mind. The choices of starter and alternator/generator are the main differences, and once you put those on, plus exhaust, baffles, etc., on either of them they are both going to be over 400#, no way around it. The next big difference is in props. I will get to that in a minute.

              About 12 years after getting this engine, after a long list of “life” delays, I have just yesterday gotten my new engine mount from BH Aircraft - Thank You, V. Irwin!
              Just hanging on two bolts for the picture… Now I can proceed to at least mount the engine, so I can lay out firewall penetrations and such, and work on the cowling, and the intake and exhaust routing, etc., etc.

              But here’s the drawback I have run into, and is something to consider before going down this road - the O-470 series pretty much has to use a certified propeller. There simply really aren’t any other options available, outside of doing your own R&D or taking a chance on some sketchy experimental choices that are out there. I will explain this best I can, with a little background, naturally.

              Since this package included the two-blade Hartzell constant-speed prop from the 310, I was thinking I was well ahead of the game. Right after I got the engine, an A&P friend of mine came to see it, and he mentioned that there was an AD on that series of prop. I thought, great, well I will cross that bridge when I come to it. That bridge sort of happened last week - the mount was on the way, so I started dusting off the old stuff, the engine and all the parts in boxes, and the prop - re-acquainting myself with all of it. I got the model number off the prop and looked up the AD, and it concerns cracks in the blade mounting system on the hub, and requires on-going inspection, every 500 hours. That includes UV particle, magnetic particle, and optical comparator testing every time - so I’m thinking $$,$$$.

              I called the Hartzell Service Center to ask about my options for an overhaul. The prop is considered obsolete in their system. But, they have a modification (the MV hub/shank system) that can be done to permanently address the AD, by reworking (via extensive machine work) the hub, clamps and blades - all for about the same cost as 3 new 3-blade propellers. The best, safest, most cost-effective option they have is to just buy a new propeller. And that actually isn’t a ridiculous option, but it is still two to three times what I expected a simple overhaul to cost…

              Well, since I am buying a new prop, what about these new composite ones? Nope - the 6-cylinder Continentals have a minimum polar moment of inertia requirement - composite props are too light. It seems the crankshaft and counterweight system of these engines is designed for what were the normal props of the day; steel hubs, aluminum blades. So all of the experimental-arena composite designs are not recommended - by Continental. Bad vibration and cracks can ensue… So this isn’t a propeller manufacturer thing. And it seems that that is likely why all the major experimental prop companies don’t have anything for Continental 6’s. At least nothing I could find.

              That said, there are several very nice 2 and 3-blade propellers available from both Hartzell and McCauley. The “scimitar” blade designs are available as retrofits for Cessna 180’s and 182’s and 185’s, and others - so there are options. But you have to be careful to select the correct compression ratio, RPM, and counterweight system to match the prop, so pick the O-470-() or IO-470-() or IO-520-() model number carefully. Actually, all of the 520’s have the same counterweight system (1-4th, 1-5th, 2-6th orders), so pretty much any prop for a 520 will work on another 520 as long as you aren’t increasing the compression ratio or RPM from the prop application’s base engine. Anything else is getting into the R&D thing, as well as trying a composite prop of any kind.

              Because of this sort of limited range of propellers, the weight is almost always going to be at least 60-80 pounds for the prop. Keep this in mind if you are concerned about nose weight and CG.

              Last edited by BradW1062; 04-10-2024, 10:42 AM.


              • nellie2110
                nellie2110 commented
                Editing a comment
                Could you clear something up for me, you mention composite props and later your mention experimental composite. Are you saying the MT or trailblazer prop are not OK on a 470 or 520? There are stc's and many (certified props per the stc) of these props on 470 and 520 engines. Or where you talking catto type props only?

              • BradW1062
                BradW1062 commented
                Editing a comment
                I asked directly if there was a Trailblazer option for an O-470 (whichever letter), since I know they are available for O-540 Bearhawks, in the Hartzell application guide. But, the person at Hartzell specifically told me that the Trailblazer is not an option for the O-470 because it is composite, and that Hartzell doesn't have any composite options for the O-470, but wasn't sure exactly why (didn't say what the problem specifically was). I just assumed it was because of limited demand or something. I was referred to the Hartzell Manual 193 which is for experimental applications, for more information on this.

                Then, I found info in the Manual 193 (vol 2, page 5-5) that mentions the minimum polar moment of inertia requirement for Continental 6's. This Hartzell manual says that this is "part of the installation manual" for a Continental 6-cylinder engine, and that Hartzell is aware of this limitation. Well, I have not been able to find that information specifically in any of the Continental documents that I have, so I am not sure exactly what the minimum is. The only Continental documents that I can find regarding installation are the "Operation and Installation" or "Operator's" manuals, and I have not been able to find anything in them referencing or specifying a polar moment of inertia. The only reference at all in my O-470 Operator's Manual, X30097, 2011 is under the specifications and limits section where it details "Propeller Drive Data", and lists flange type, clockwise rotation, direct drive, and damper number and order. That's the closest thing I have found. It is still a mystery for me, but I wanted to mention it here to hopefully help others who are considering this engine. It was surprising news to me.

                I don't know anything about the MT props, but I did see somewhere that someone was touting them as better for 180/182's specifically because they had "lower inertia" than metal props. I don't know if this is enough lower to be in conflict with whatever concern Continental may have about minimum inertia. I would definitely ask MT that question though, knowing what I know now. I would ask them if they are aware of any inertia limitations from Continental on their 6-cylinder engines. Since MT is a relatively large manufacturer, they have probably worked this out already. So they are probably and equal option with Hartzell and McCauley for "certified" type propellers, even though they have wood-composite propellers.

                I guess if an aftermarket or experimental-only propeller manufacturer has done the vibration testing of their props, then great, no problem. But to just take an off the shelf composite prop like a Catto or a Whirlwind or Sensenich airboat prop or something that is intended for a O-540 and put it on an O-470 with some adapter seems to be pushing the risk level up a bit from what I have learned. That's the experimental R&D area I was referring to. And by experimental-arena composite, I did mean things like Catto, Whirlwind, Ivoprop electric variable pitch, and Warpdrive ground adjustable, etc. - not just the constant-speed stuff. They ones that are sold for non-certified experimental aircraft. One fella on here was asking about using fixed pitch props on an O-470, I think. There are not very many of those at all in the certified world (Bird Dogs and Ag Trucks probably are all), but there is an endless variety of bolt-together and bolt-on ground-adjustable fixed-pitch carbon fiber props out there, and that is what I was really concerned about when I say "experimental composite" really. If Catto or Whirlwind say they have a prop for O-470's then fine, but I just haven't seen that so far.


            • #8
              I think AZBearhawk272 is especially equipped to chime in here. As I recall he has a Trailblazer and a Continental?


              • BradW1062
                BradW1062 commented
                Editing a comment
                Yes, I would very much like to hear about that. And if it was a "factory approved" option, that he purchased from Hartzell, then I am also wanting to question why I was told by the Hartzell rep that there are no Trailblazers, or other composite options for the O-470. Hmmmmm, things that make you scratch your head...

                I did specifically discuss converting the engine to another model with the appropriate counterweight system for matching one of their available metal props, and I mentioned that I was probably going to 8.6 compression and an IO-470 model as well. So if the Trailblazer is available for an IO-470, they failed to mention that to me. Maybe they didn't understand my southern accent or something.

            • #9
              Continental doesn't seem like it ever catered to the experimental crowd, and maybe Hartzel just can't deal with them.Lots of liability issues in aviation. I am not sure I blame them.


              • #10
                Hartzell did provide me a 3 blade trailblazer composite prop for my IO-470. No issues, coordinated the activity through Mark. Seems to work well so far.
                Kevin D
                272 KCHD


                • BradW1062
                  BradW1062 commented
                  Editing a comment
                  Kevin - I would like to know the details of that if you don't mind. I can't understand why they would tell me they don't have the Trailblazer for an IO-470, after selling you one. That simply doesn't make any sense.

                  What did you or MG tell them the application was to get such easy cooperation?

              • #11
                Appreciate the info everyone. I should have double checked with my neighbor before I said trailerblazer on a 470 or 520. It was a simatar he installed on a Pponk(470 convert to O-520).

                As for MT the place that has most the Stcs in the USA is flight resource. The link below is to their site and if you scroll down to cessna you can choice just about any 470 or 520 in one of those airframe. So I would say MT is a composite(wood core/composite wrap) option for 470s and 520s.


                • #12
                  I can't seem to get Hartzell to take an order for a prop they say they support. I've been working with Mark and then Virgil for a couple months and they won't respond to attempts to place an order. I was more than a little concerned when they were bought by a private equity firm...


                  • #13
                    I think the 470 is a great engine choice. While I’m happy with my Continental IO360 I do wish I had gone with an IO470. I only cared to look at McCauley Props, MTs and some other experimental prop options so so can’t comment on much. The proven Mac C203 is a hard prop to beat and they can be found cheap. I bought mine for $2600: 3 years old, 300hours and looked brand new. MT props were the hot ticket for a while on C180/182s and many folks still really like them. There is concern that the low inertia of the lighter prop may cause the starter adapter more susceptible to kickback damage. Whirlwind will put their blades on a McCauley hub. Catto has a constant speed option too, I think.

                    If I were putting an engine on my plane today it would be an IO470 with a 86” Mac C203 or possibly the Catto.

                    I was told there are two different length 470 mounts. One fits the carbureted engine and the other fits the fuel injected. Might be worth checking on that and making sure you have the one you want.
                    Scratch Built 4-place Bearhawk. Continental IO-360, 88" C203 McCauley prop.


                    • #14
                      The paperwork with my Hartzell propeller indicates HC-C3YF-1NX/NG8304-3X
                      It indicates the propeller is an experimental propeller configuration for installation on an Experimental Aircraft.
                      Propeller control is a matched Hartzell propeller governor.
                      I will be performing a balancing and vibration spectra survey in the next few weeks.
                      Engine is IO-470D.

                      Kevin D
                      #272 KCHD


                      • BradW1062
                        BradW1062 commented
                        Editing a comment
                        Thanks Kevin! I got a response from a Tech Support engineer at Hartzell. He said the minimum propeller polar moment of inertia that Continental specifies is in the Engineering Installation Manual from Continental, and that he can’t disclose that information. So no help for those of us who are not manufacturers I guess, or maybe Continental charges a nice price for that info.

                        He told me that they do not sell a “Trailblazer” prop for the IO-470, that those are Lycoming-specific 2 and 3 blade *lightweight* composite props. So they don’t technically call your prop a Trailblazer. I think that is where the confusion starts. But, he also gave me exactly the model numbers you have above as the “heavyweight” composite blades that are required for the IO-470. They just haven’t assigned a “brand name” to that series of props like they have the others - it is simply the composite blade option in the Top Prop series. He also said he will talk to the support people at the service center to make sure they understand that there is a composite option with the heavier NG8304 blades. So there ya go.

                        I look forward to some data on the vibration measurements…

                    • #15
                      What an interesting level of nuance and complexity created by themselves...