25 Apr 2024, 06:37 [ UTC - 5; DST ]
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Post subject: Re: Cessna 340 vs 414 vs the 421 Posted: 29 Aug 2019, 21:42 |
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Joined: 02/09/09 Posts: 5599 Post Likes: +2559 Location: Owosso, MI (KRNP)
Aircraft: 1969 Bonanza V35A
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Username Protected wrote: those are some mighty big claims they are making. Cant wait to get your report.
I don't have the data anymore (well, I might, but am too lazy to dig it up), but we did the first series on the 421C that I managed about five or six years ago and I recorded a noticeable difference in the rate of climb and the cruise speed. I was surprised how much difference a simple hubcap could make. The first version that we had didn't have doors for the air, so you had to take the three screws out each time you needed to check the tire pressure. It took about an hour to install them, and I did it without removing the wheels from the airplane.
I'm not sure why we didn't choose to put them on the 441...
It's one of the cheapest, simplest speed mods you can do on a Twin Cessna that doesn't have full landing gear doors.
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Post subject: Re: Cessna 340 vs 414 vs the 421 Posted: 29 Aug 2019, 21:54 |
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Joined: 08/09/11 Posts: 1739 Post Likes: +2058 Company: Naples Jet Center Location: KAPF KPIA
Aircraft: EMB500 AC95 AEST
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Username Protected wrote: This was missing from the previous email That’s fine and it’s nice to look at but it really says nothing. It’s reminds me of the Tamarack winglet; if the strakes are that helpful, the 421 doesn’t have enough power or wing for that regime. Entirely possible. Strakes can be really effective at adding lift to the plane. But they look almost vertical on the 421 application. Look at a Lear and you can see where they would add lift at relatively high AOA. Anyway, seems like there is no reason there isn’t published data other than it doesn’t really work as good as the marketing. IMHO of course. Even more so with hub caps. You could take those off and on on the same day easy and do back to back flights with some semblance of an experiment.
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Post subject: Re: Cessna 340 vs 414 vs the 421 Posted: 29 Aug 2019, 22:00 |
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Joined: 11/27/12 Posts: 955 Post Likes: +916 Location: Outer Banks
Aircraft: F33, 421C
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Username Protected wrote: Hub caps do work. I flew a 1000 hours without them and 600 hours with them. +1 For the hubcaps. You will see a difference!
_________________ The “Rattler”
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Post subject: Re: Cessna 340 vs 414 vs the 421 Posted: 29 Aug 2019, 22:41 |
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Joined: 12/03/14 Posts: 19252 Post Likes: +23622 Company: Ciholas, Inc Location: KEHR
Aircraft: C560V
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Username Protected wrote: those are some mighty big claims they are making. Cant wait to get your report. "Our Cessna 405 series III Speed Covers offer fuel savings 5-10%. Horizontal distance flown reduced by 18% with an increased rate of 25% on climb. Extra lift, reduced drag, lower angle of attack in climb, cruise and descent." Sounds like it reduces range by 18% while saving 10% on fuel. Weird. If you like the way they look, go for it. If you want 10% fuel savings, you are looking in the wrong place. Mike C.
_________________ Email mikec (at) ciholas.com
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Post subject: Re: Cessna 340 vs 414 vs the 421 Posted: 30 Aug 2019, 11:18 |
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Joined: 11/19/15 Posts: 1402 Post Likes: +1205 Company: Centurion LV and Eleusis Location: Draper UT KPVU-KVNY
Aircraft: N45AF 501sp Eagle II
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Username Protected wrote: This was missing from the previous email Worse part of this graph is the stock 421 is under 400fpm from FL200 to FL2500? that can't be true? Man that's worse than my Mirage. Mike
_________________ InstaGram @Mtpyle company @CenturionLV @eleusisdigitalcanvas race team @strappedracing
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Post subject: Re: Cessna 340 vs 414 vs the 421 Posted: 30 Aug 2019, 11:27 |
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Joined: 03/16/13 Posts: 51 Post Likes: +92
Aircraft: CE-510
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Worse part of this graph is the stock 421 is under 400fpm from FL200 to FL2500? that can't be true? Man that's worse than my Mirage.
It's been several years since I sold my 421C, but she really wheezed above FL200. I think I only climbed to FL250 once because the last few thousand feet were so painfully slow.
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Post subject: Re: Cessna 340 vs 414 vs the 421 Posted: 30 Aug 2019, 11:36 |
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Joined: 10/27/10 Posts: 10861 Post Likes: +6885 Location: Cambridge, MA (KLWM)
Aircraft: 1997 A36TN
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Username Protected wrote: those are some mighty big claims they are making. Cant wait to get your report. "Our Cessna 405 series III Speed Covers offer fuel savings 5-10%. Horizontal distance flown reduced by 18% with an increased rate of 25% on climb. Extra lift, reduced drag, lower angle of attack in climb, cruise and descent." Sounds like it reduces range by 18% while saving 10% on fuel. Weird. I think that's the quoted distance and fuel to the top of climb point. In other words, the airplane climbs at a faster rate and a steeper angle.
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Post subject: Re: Cessna 340 vs 414 vs the 421 Posted: 30 Aug 2019, 15:08 |
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Joined: 01/31/10 Posts: 13101 Post Likes: +6970
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Username Protected wrote: I put hubcaps on my 414A several years ago and they worked as advertised. They really helped with climb and high altitude cruise speeds.
I recently put them on my 425 but they don't seem to make any noticeable difference. Why is that? On my 421C, they helped at the highest AOAs the most. That made for a significant improvement in the 20s where the pistons really struggle for altitude. The 425 doesn't have that issue. Just an educated guess.
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Post subject: Re: Cessna 340 vs 414 vs the 421 Posted: 31 Aug 2019, 19:53 |
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Joined: 02/09/09 Posts: 5599 Post Likes: +2559 Location: Owosso, MI (KRNP)
Aircraft: 1969 Bonanza V35A
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Username Protected wrote: This was missing from the previous email Worse part of this graph is the stock 421 is under 400fpm from FL200 to FL2500? that can't be true? Man that's worse than my Mirage. Mike
At gross weight, especially ISA+10 or more, our 421C was a 500 FPM airplane after 10,000' at 140 KIAS. I spent many days climbing for 45 minutes to get to the low 20's. It would climb, but it was a dog.
The other problem I ran into is once you get into the flight levels, you usually end up in ice. At ISA+10 days, you just plain run out of energy to climb. I ran into a situation where I couldn't climb out of the tops at FL210 one summer day due to light rime ice and just not enough power.
I usually climbed at the top of the green on MP/RPM, even though it was certified to climb at full MP/RPM.
That was one of the very few negatives with the 421C.
Jason
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Post subject: Re: Cessna 340 vs 414 vs the 421 Posted: 01 Sep 2019, 01:47 |
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Joined: 12/03/14 Posts: 19252 Post Likes: +23622 Company: Ciholas, Inc Location: KEHR
Aircraft: C560V
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Username Protected wrote: At gross weight, especially ISA+10 or more, our 421C was a 500 FPM airplane after 10,000' at 140 KIAS. I spent many days climbing for 45 minutes to get to the low 20's. It would climb, but it was a dog. The POH suggests you weren't configuring it for good climb rates. See the climb chart (1976 421C): Attachment: 421c-climb-rates.jpg The red lines represent the following altitudes: 0 MSL - 1950 FPM 10K MSL - 1550 FPM 20K MSL - 1200 FPM This assumes ISA and gross weight (7450 lbs). Climb speed is 111 KIAS to 20K. So using max power and best climb speed seems to make a very big difference. The cruise climb chart uses 1900 RPM and 32.5 MAP and 120 KIAS and achieves: 0 MSL - 1220 FPM 10K MSL - 960 FPM 20K MSL - 720 FPM If a 421C is realistically a 500 FPM plane above 10K MSL, I am sure glad I didn't buy one. Mike C.
Please login or Register for a free account via the link in the red bar above to download files.
_________________ Email mikec (at) ciholas.com
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