28 Nov 2025, 00:20 [ UTC - 5; DST ]
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Post subject: Re: Cessna 340 vs 414 vs the 421 Posted: 04 Nov 2015, 02:09 |
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Joined: 01/29/14 Posts: 206 Post Likes: +73
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Username Protected wrote: 520 vs 550 is only a 6% change in displacement. Relatively trivial. The main thing that allows more power is 40" manifold pressure and 3300 rpm. Good point. Though I thought it may make a difference when you are trying to get absolute max power out of an engine. For example there is a considerable improvement in performance of my P210 after going from a 520 to a 550. Both engines are rated at 310hp, yet I have picked up nearly 15kts in cruise at 80% power, and a much better rate of climb. I don't know where this additional performance comes from. More torque? Crossflow heads? In any event, I thought the engines may be suitable for the big twins.
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Post subject: Re: Cessna 340 vs 414 vs the 421 Posted: 04 Nov 2015, 07:55 |
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Joined: 01/09/13 Posts: 1249 Post Likes: +246 Location: Frederick , MD (KHGR)
Aircraft: C421 B36TC 58P
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Username Protected wrote: Does anybody have before and after experience with strakes? I've heard 8-10 kt tas increases recently from several sources...true? Jack- the stakes are a mod that cost $20,000 i believe.. 5-10 its not a game changer.
_________________ Good Luck,
Tim -------------------
Last edited on 04 Nov 2015, 09:44, edited 1 time in total.
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Post subject: Re: Cessna 340 vs 414 vs the 421 Posted: 04 Nov 2015, 08:24 |
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Joined: 04/28/09 Posts: 1556 Post Likes: +108 Company: ARC Group Medical Location: Jacksonville , FL (KCRG)
Aircraft: 1976 Bonanza V35TN
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Username Protected wrote: 520 vs 550 is only a 6% change in displacement. Relatively trivial. The main thing that allows more power is 40" manifold pressure and 3300 rpm. Good point. Though I thought it may make a difference when you are trying to get absolute max power out of an engine. For example there is a considerable improvement in performance of my P210 after going from a 520 to a 550. Both engines are rated at 310hp, yet I have picked up nearly 15kts in cruise at 80% power, and a much better rate of climb. I don't know where this additional performance comes from. More torque? Crossflow heads? In any event, I thought the engines may be suitable for the big twins.
One thing to remember is that the GTISO motors are the top induction angle valve motors so it not quite the same as your typical 520-550 conversion. Also the GTISO were rated with the accessories. The GTISO in the 421 are not at it max potential rating really....I believe there are some version up in the 425hp range.
_________________ Former GenX Bonanza owner.... now flying the 421 Golden Turkey
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Post subject: Re: Cessna 340 vs 414 vs the 421 Posted: 04 Nov 2015, 09:36 |
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Joined: 08/20/09 Posts: 2665 Post Likes: +2242 Company: Jcrane, Inc. Location: KVES Greenville, OH
Aircraft: C441, RV7A
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Username Protected wrote: I flown a few with and without and I think it depends if it's a B or C and wether it has winglets or not.... So I'm assuming winglets would diminish the value of strakes? Or is it the other way around?
_________________ Jack N441M N107XX
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Post subject: Re: Cessna 340 vs 414 vs the 421 Posted: 04 Nov 2015, 12:02 |
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Joined: 03/24/08 Posts: 2893 Post Likes: +1146
Aircraft: Cessna 182M
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Username Protected wrote: Why do the 421s use a 520 engine to produce 375 hp?
I would have thought a 550 would be better suited? Has anyone ever done a stc to put 550s in?
Or is it just two hard to match the gearing? Most likely b/c the 550 did not exist circa 1967 or so when Continental began producing motors for the 421. As to just dropping in a 550 now, the angle valve cylinders on the GTSIO probably make that not possible. RAS
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Post subject: Re: Cessna 340 vs 414 vs the 421 Posted: 04 Nov 2015, 14:14 |
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Joined: 02/09/09 Posts: 6530 Post Likes: +3240 Company: RNP Aviation Services Location: Owosso, MI (KRNP)
Aircraft: 1969 Bonanza V35A
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Username Protected wrote: - 1 item that I will often do is reduced takeoff thrust.. do this but the engines on the 421C run very cool... or cooler than the P baron engines.. I can't remember the reason at the moment, but there is s very good reason not to do reduced power takeoffs in any turbocharged Continental. I only seem to remember that mechanically something goes over enter in the FCU prohibiting fuel flow. I've been unable to reach the Maintenance a Manager that explained it to me 20 years ago. It was very clearly prohibited by him in our fleet of 15 (GTSIO) aircraft. Jason
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Post subject: Re: Cessna 340 vs 414 vs the 421 Posted: 04 Nov 2015, 14:54 |
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Joined: 12/15/10 Posts: 595 Post Likes: +301 Location: Burlington VT KBTV
Aircraft: C441 N441WD
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Username Protected wrote: Does anybody have before and after experience with strakes? I've heard 8-10 kt tas increases recently from several sources...true? Jack- the stakes are a mod that cost $20,000 i believe.. 5-10 its not a game changer. Ours were $15,300 installed. (APM Strakes).
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Post subject: Re: Cessna 340 vs 414 vs the 421 Posted: 04 Nov 2015, 15:28 |
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Joined: 01/09/13 Posts: 1249 Post Likes: +246 Location: Frederick , MD (KHGR)
Aircraft: C421 B36TC 58P
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Username Protected wrote: - 1 item that I will often do is reduced takeoff thrust.. do this but the engines on the 421C run very cool... or cooler than the P baron engines.. I can't remember the reason at the moment, but there is s very good reason not to do reduced power takeoffs in any turbocharged Continental. I only seem to remember that mechanically something goes over enter in the FCU prohibiting fuel flow. I've been unable to reach the Maintenance a Manager that explained it to me 20 years ago. It was very clearly prohibited by him in our fleet of 15 (GTSIO) aircraft. Jason
Jason-- I would love to see the evidence if you can locate it discouraging the reduce power takeoff.. thanks
_________________ Good Luck,
Tim -------------------
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Post subject: Re: Cessna 340 vs 414 vs the 421 Posted: 04 Nov 2015, 23:33 |
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Joined: 02/27/08 Posts: 3452 Post Likes: +1499 Location: Galveston, TX
Aircraft: Malibu PA46-310P
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Username Protected wrote: Wow, six pages and no one has brought up T-Bone or Duke.  Tim Tim, Shhhhhhhh.... Don't distract them. Besides dukes are pigs and don't fly LOP Kevin
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Post subject: Re: Cessna 340 vs 414 vs the 421 Posted: 05 Nov 2015, 01:55 |
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Joined: 10/04/14 Posts: 493 Post Likes: +113 Company: Take Flight Avaition. Location: Franklin, TN
Aircraft: Piper PA46 Jet Prop
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Username Protected wrote: Wow, six pages and no one has brought up T-Bone or Duke.  Tim Tim, Shhhhhhhh.... Don't distract them. Besides dukes are pigs and don't fly LOP Kevin
But Dukes are cool. Would I look cool in a Duke.
https://m.youtube.com/watch?v=pnCT24qod4M
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Post subject: Re: Cessna 340 vs 414 vs the 421 Posted: 05 Nov 2015, 08:20 |
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Joined: 11/06/10 Posts: 12192 Post Likes: +3076 Company: Looking Location: Outside Boston, or some hotel somewhere
Aircraft: None
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Username Protected wrote: Tim Doreen, you are right there is no reason why it is wrong to make reduced power departures.
No one can up with anything other than OWT's. Or bs they heard. I Watch the fuel flow as you throttle up. It has never looked linear to me in either my Cirrus or Aerostar. As such, one inch of MP at full power gives a lot more fuel then one inch farther down. So I am fairly certain that reduced power take off you are dramatically affecting the fuel air ratio which likely is reducing how far ROP you are. This may or may not increase the stress on the engine. Tim
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