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Post subject: Re: Lancair IV-p  Posted: 06 Aug 2016, 23:35 |
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Joined: 11/03/08
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Location: Peachtree City GA / Stoke-On-Trent UK
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Username Protected wrote: Don't you think if you can avoid shard temp. changes 50 percent of the time that would be beneficial ? yes, that's why I'd avoid crashing into a freezing cold lake at full power. I can't think of any other way to get a "sharp temperature change" on these engines.
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Post subject: Re: Lancair IV-p Posted: 06 Aug 2016, 23:36 |
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Joined: 08/20/09
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Company: Jcrane, Inc.
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Username Protected wrote: Don't you think if you can avoid shard temp. changes 50 percent of the time that would be beneficial ? The MVP-50 engine monitors in our 421 had a datablock dedicated to 'S.Cool' when we bought the plane. In climb/cruise/etc it shows 0°F/M shock cool. Typical cruise is 32.5" MP. If I need a quick descent and pull the power back from 32.5" to 25" in less than 2 seconds I may see 10°/M shock cool. I can't imagine how that's a problem.
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Jack
N441M N107XX
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Post subject: Re: Lancair IV-p Posted: 06 Aug 2016, 23:38 |
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Joined: 12/13/07
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Location: Seeley Lake, MT (23S)
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Username Protected wrote: Don't you think if you can avoid shard temp. changes 50 percent of the time that would be beneficial ? 1.) Define shock cooling. How many degrees per minute? 2.) How fast does your engine cool at 2 inches per minute? 4 inches?
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Post subject: Re: Lancair IV-p Posted: 06 Aug 2016, 23:50 |
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Joined: 08/03/08
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Username Protected wrote: but for landing I don't like to reduce power any more than one inch per minute until I reach about 23 inches or so. I used to do the same thing, until I had good engine monitors. Shock cooling is an OWT, in my observation.
It has been shown to exist in glider tugs. Full power at low speed followed by immediate dive for the runway at idle.
I don't think it exists in regular cruise operations.
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Post subject: Re: Lancair IV-p Posted: 06 Aug 2016, 23:52 |
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Joined: 08/01/11
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Location: In between the opioid and marijuana epidemics
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I shock cooled my engine flying through moderate cold rain.
There are some on here who actually fly engines that have been submerged.
Still running last I checked.
I shock heated my plane 4 times yesterday.
Clearly I need a new engine.
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"Paranoia and PTSD are requirements not diseases"
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Post subject: Re: Lancair IV-p Posted: 06 Aug 2016, 23:54 |
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Joined: 11/03/08
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Location: Peachtree City GA / Stoke-On-Trent UK
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Username Protected wrote: It has been used as a scapegoat in glider tugs. Full power at low speed followed by immediate dive for the runway at idle which causes no problems, just as it causes no problem in jump planes.
I don't think it exists in regular cruise operations. fixed that for you
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Post subject: Re: Lancair IV-p Posted: 06 Aug 2016, 23:55 |
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Joined: 12/01/12
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Company: Minnesota Flight
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Shock cooling talk should keep this thread going for a while. But one better.......
RDD is putting BRS parachutes in the Lancairs. Will this make the plane safer or just give a false sense of security to under qualified and under trained pilots resulting in more crashes and chute pulls? They want to take some of the cirrus market with their conversion.
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Post subject: Re: Lancair IV-p Posted: 06 Aug 2016, 23:57 |
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Joined: 12/25/12
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Username Protected wrote: but for landing I don't like to reduce power any more than one inch per minute until I reach about 23 inches or so.
It has been shown to exist in glider tugs. Full power at low speed followed by immediate dive for the runway at idle.
I don't think it exists in regular cruise operations.
I would do flat inverted spins full throttle to 800agl then idle to landing never had a problem. It's taking off with a cold engine. The problem on the 421 with the gtsio engines is pushing the prop on geared engines.....if it's a problem at all.
Sorry if I screwed up the quotes
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Last edited on 06 Aug 2016, 23:58, edited 2 times in total.
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Post subject: Re: Lancair IV-p Posted: 06 Aug 2016, 23:57 |
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Joined: 01/06/13
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I don't see a drastic change in temps. at one inch per minute, about 5 or 6 degrees, best I remember, but with dissimilar metals in the cylinder, seems like the easier you can be the better. Everyone should operate as they see fit.
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Post subject: Re: Lancair IV-p Posted: 06 Aug 2016, 23:59 |
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Joined: 12/01/12
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Company: Minnesota Flight
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Username Protected wrote: It has been used as a scapegoat in glider tugs. Full power at low speed followed by immediate dive for the runway at idle which causes no problems, just as it causes no problem in jump planes.
I don't think it exists in regular cruise operations. fixed that for you
Fly a super cub? Put 180+ hp in it. Fly it slow at full throttle. They don't have engine monitors for a reason. If you can't see the CHT at 420+ it didn't happen right? Cooling is the least of their worries. More like lack of.
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Post subject: Re: Lancair IV-p Posted: 07 Aug 2016, 00:01 |
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Username Protected wrote: Shock cooling talk should keep this thread going for a while. But one better.......
RDD is putting BRS parachutes in the Lancairs. Will this make the plane safer or just give a false sense of security to under qualified and under trained pilots resulting in more crashes and chute pulls? They want to take some of the cirrus market with their conversion. seems like a lot of the accidents are in the approach & landing phase so I'd not rate a BRS too useful. I don't think a chute fixes some of the things you see in this very thread: "I'm so good I don't need training or insurance, anyone who says otherwise must be an incompetent fool because that's who needs training, I could TEACH how to fly this thing I'm so good, hey what are these speed brakes they seem to be important but I don't what I'm doing and I'm creating a hazard with them"
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Post subject: Re: Lancair IV-p Posted: 07 Aug 2016, 00:17 |
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Joined: 08/03/08
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Username Protected wrote: It has been used as a scapegoat in glider tugs. Full power at low speed followed by immediate dive for the runway at idle which causes no problems, just as it causes no problem in jump planes.
I don't think it exists in regular cruise operations. fixed that for you
If fixed means 'inserted my own bias', then yes, you 'fixed' it.
Lasham gliding society in the UK looked at this. Between 87 and 91 they did about 60,000 aero-tows and replaced 28 cylinders along the way (2 after barrel separations). Their SOP at the time was to release the glider, pull back to idle and to immediately dive for the runway to pick up the next tow. They then changed their SOP to reduce power over a period of about 30seconds and to initiate the descent gradually. Their cylinder cracking issue went away.
Jump planes already do this as part of routine operation. Every skydive I have ever done was from a plane that had leveled out at altitude at a reduced power setting for the jump-run. So unless there is someone out there who drops skydivers while in a full power climb, the fact that jump planes don't see this is not a counter-argument.
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Post subject: Re: Lancair IV-p Posted: 07 Aug 2016, 10:08 |
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Joined: 05/05/09
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Aircraft: C501, R66, A36
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Username Protected wrote: Shock cooling talk should keep this thread going for a while. But one better.......
RDD is putting BRS parachutes in the Lancairs. Will this make the plane safer or just give a false sense of security to under qualified and under trained pilots resulting in more crashes and chute pulls? They want to take some of the cirrus market with their conversion. seems like a lot of the accidents are in the approach & landing phase so I'd not rate a BRS too useful. I don't think a chute fixes some of the things you see in this very thread: "I'm so good I don't need training or insurance, anyone who says otherwise must be an incompetent fool because that's who needs training, I could TEACH how to fly this thing I'm so good, hey what are these speed brakes they seem to be important but I don't what I'm doing and I'm creating a hazard with them"
I would much rather fly with someone who has scientifically and rationally experimented with their aircraft in different configurations. You're wrong on discouraging this with your sweeping blanket statements that serve more to be hostile than constructive. While learning any new airplane, we often place it in non routine configurations. A perfect example is multi engine training. By your example, I guess you encourage never shutting a motor down or shooting a single engine ILS? You probably never encourage practicing partial panel or no flap landings too by your mistaken logic? I am glad I know what my speed brakes on my Lancair do in all stages of flight; not just the descent phase. Maybe one day I will need this knowledge.
Jeff, do you own a Lancair? Do you own a GA airplane with speed brakes?
Last edited on 07 Aug 2016, 15:24, edited 1 time in total.
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