Twins are No Safer Than Singles

[jaylw314]

  On 7/12/2021 at 11:01 PM, EricJ said:

Uh, that's the peer-review part.   Believe me, the desire to shoot down flaws in somebody else's research is strong among academia, and most academic or society journals have a reasonable blind review process populated with both academic and industry reviewers.     I've been on both sides, as an author and as a reviewer, and while it's certainly not bullet proof it generally produces good results.   When it doesn't produce good results, the likelihood of somebody else publishing a follow-up pointing that out is pretty good.

Some journals do this better than others, so like anything, one must consider the sources.   The reputable journals put a lot of effort into keeping the process working in order to maintain the reputation and attract quality papers. 

All that said it is getting harder for many journals to stay relevant or functional given the crazy ways that information flows these days.   Authors, reviewers, and editors are generally not compensated in most journals, and if a journal makes access and distribution difficult by limiting access through restrictive fees, etc., the system starts to shrink in relevance.   A bad thing on the horizon may be the loss of a lot of peer-reviewed publication organizations, just under the weight of maintaining the system.

Anyway, just another 0.02.

 

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The bolded sentence is kind of what I'm talking about

Peer-review mitigates study design errors, and maybe some forms of bias, but not academic bias because it's a PRE-publication problem that you can't review after the fact.  I suppose you could say the same for financial bias (another pre-publication problem), but at least there's a culture of financial disclosure in research.

There's been at least some talk of stuff like pre-approving publication based on study design rather than study results, so you'd agree to publish someone's article only before they knew what the results were.  We'd start getting a more confident picture of all the negative study results out there that we never hear about (unintentionally or intentionally).

Anyway, sorry about the thread drift...

Edited July 13, 2021 by jaylw314

[jaylw314]

  On 7/12/2021 at 10:35 PM, smwash02 said:

Twinkies are Twin Comanches

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Ooooh, ok, thanks! 

[aviatoreb]

  On 7/12/2021 at 2:14 PM, A64Pilot said:

You  have to be careful with stats, when I lived in Germany my neighbor told me that German’s have a saying, “Statistics are like a lady of the evening, if your paying, you get what you want”

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Its fun to say that - and of course there is always the famous "How to Lie with Statistics", https://www.amazon.com/How-Lie-Statistics-Darrell-Huff/dp/0393310728/ref=asc_df_0393310728/?tag=hyprod-20&linkCode=df0&hvadid=312014159412&hvpos=&hvnetw=g&hvrand=8701803441843384516&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9005342&hvtargid=pla-432731750539&psc=1

but there is nothing wrong with (the mathematics of) statistics.  But it is easy to bamboozle people with lots of fancy looking math and some people do make a game and habit of it.  I don't think that is the usual thing though.

  On 7/12/2021 at 9:42 PM, Scott Dennstaedt, PhD said:

That's why I only read peer-reviewed journals for this kind of stuff.  It's more objective and there's typically no axe to grind.  Although the ASI's Nall Reports are pretty darn good.

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You are reading us here.  :-). but we do enjoy your participating.

 

  On 7/12/2021 at 11:01 PM, EricJ said:

Uh, that's the peer-review part.   Believe me, the desire to shoot down flaws in somebody else's research is strong among academia, and most academic or society journals have a reasonable blind review process populated with both academic and industry reviewers.     I've been on both sides, as an author and as a reviewer, and while it's certainly not bullet proof it generally produces good results.   When it doesn't produce good results, the likelihood of somebody else publishing a follow-up pointing that out is pretty good.

Some journals do this better than others, so like anything, one must consider the sources.   The reputable journals put a lot of effort into keeping the process working in order to maintain the reputation and attract quality papers. 

All that said it is getting harder for many journals to stay relevant or functional given the crazy ways that information flows these days.   Authors, reviewers, and editors are generally not compensated in most journals, and if a journal makes access and distribution difficult by limiting access through restrictive fees, etc., the system starts to shrink in relevance.   A bad thing on the horizon may be the loss of a lot of peer-reviewed publication organizations, just under the weight of maintaining the system.

Anyway, just another 0.02.

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I don't feel "my people" are all that controversial - being a math academic - a lot of what goes on in our refereeing world is more about what is interesting or not interesting (which is a matter of taste as to what are the important problems) to get into the fancier journals but less so correct or not.  In math at least, no one is getting rich.

[N201MKTurbo]

Statistics are always accurate and they can be validated, but the data is anybody’s guess.

[Hank]

  On 7/13/2021 at 2:25 AM, N201MKTurbo said:

Statistics are always accurate and they can be validated, but the data is anybody’s guess.

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"There are lies, damned lies and statistics."--Samuel Clemens 

[carusoam]

Too soon for topic drift?

I have debated the twin vs. single many times before…

The arm chair weekend pilot… vs. EFATO….

The local accident was probably the last training accident of an intentional go around on one engine…

So… I lost the twin argument… several times in an ordinary year… I have been unable to keep up the recency that I would like…

Still wanting the increased speed, payload, and seating that a Mooney 301 could offer… with the side benefit…

What is the side benefit of a turbine engine?

No cam corrosion…

No pistons departing the case…

No cam followers… giving lessons in metallurgy…

No camguard… to keep oil from dripping off the moving parts…

 

Do turbine engines really live up to the bullet proof reputation they have acquired?

 

Don’t trees grow large in the windshield of turbine planes as well?

Doesn’t DA play a role in Turbine performance too?

 

If I spent the mother load getting a turbine bolted to the front of my Mooney…. Would it still just cause more challenges than the ones I have already?

Jerry’s P46T is really nice… 

Tom’s PIVT is a super cool turbine four seater…

Rocket engineering has improved many Mooneys…

Could a nice turbine on a long body use a 2k’ long field?

 

It turns out… I’m not a big fan of short fields where an engine out performance includes a family neighborhood…

 

A very theoretical discussion… it would require somebody hanging a turbine on my long body… and me somehow paying for the exercise….  

Call it the turbine vs twin argument…

Best regards,

-a-

[N201MKTurbo]

  On 7/13/2021 at 2:30 AM, Hank said:

"There are lies, damned lies and statistics."--Samuel Clemens 

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GIGO

[Scott Dennstaedt, PhD]

  On 7/12/2021 at 10:23 PM, jaylw314 said:

Readers of peer-reviewed journals should look critically at who is publishing that research.  

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Been there, done that, got the PhD. Any questions???

[ragedracer1977]

  On 7/12/2021 at 1:29 AM, philiplane said:

A twin costs about 50 percent more to insure, but only because the most common claim is a gear up landing. In which case, a twin has two props and engines to repair.

You'd think insurance should cost double, or more, but it does not.

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Weird. My 310 insurance is cheaper than my Mooney insurance.  The actuaries must be dumb at my insurance co

[Guest]

PHD= Piled Higher & Deeper, knows more and more about even less!  Sorry I could resist

Clarence

[steingar]

  On 7/12/2021 at 6:42 PM, aviatoreb said:

Glad you are ok.

I love the twinkies.  What happened in that one?

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I like them too.  Bit of a story.  I think in the Aztec he lost an engine below blue line and had no choice, I think that's the version I heard (this was more than a few years ago, and I had more than a little to drink at the time).  

I went flying with him (I'd never been in a Twin Comanche, or indeed a twin of any kind), and we were at a 3K strip nestled in the Canaan valley in West Virginia.  He came in high and fast, indeed I told him to go around.  I felt a bit bad, as I thought he was the far better pilot, but I know a bad approach when I see one.  He went ahead with the landing, which was accomplished with lots of braking and some tire smoke.  Like I said, he should have gone around.

He had to try that again, and on the next landing the tire he had weakened from that first landing gave way.  We went off the runway into the weeds.  There were a bunch friends there, so we hauled it out of the weeds and into parking. Looked like sudden stoppage on both engines to me, but a mechanic came the next day and put a new tire on it and he flew away.  

Edited July 13, 2021 by steingar

[Shadrach]

  On 7/11/2021 at 8:44 PM, Tim Jodice said:

A few things to be fair to 310s and twins in general,

Not all parts cost 3 times. in fact many of the parts are the same and when you get to the airframe they only have one. 

If all Mooneys had 4 cylinder engines then yes there would be 3 times the cylinders. At the other end of Mooneys a quick look on Airpower shows you can buy 2 factory IO-470s for a 310 or Baron for one engine on a Bravo. 

A small engine (IO-470) 310/baron usually burns 25-28 GPH ROP, I personally run a Baron at 22 LOP. compared to a J typical 10GPH Close to 3 only if you running the twins at a high power. 

20% faster in cruise but they climb at a much higher rate typically going faster as well.

Useful load is the big one and the only reason I fly a twin. Most Mooneys have around 900 useful load. yes there are the few around 1000 and some very rare examples like striped Eagles that approach 1100. Most small engine Barons 310s have 15-1600 Useful and some rare examples around 17-1800. They do need to use up some of it to carry the extra fuel needed but they still have a better useful load. 

At most twice the cost to repair from a gear up. while you do have 2 engines to fix you still only have one airframe to repair the sheet metal, flaps, etc and that can be a big part of the bill.

The reason I bring all this up is because someone reading MooneySpace my want to buy a twin and unless you are comparing a Mooney 201 to a turbo 310 or 340 it doesn't cost three times as much to run.

I learned all of this from  owning a 201, partner in a Baron along with other friends that own twins.

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It is not rare for vintage mid bodies to be well over 1000ul. It’s more the norm. Going through my W&B the lowest number I could find was 1046. I’m at 1059 now and could get more if I ditched the gen,  king center stack and remote compass.

The Encores (perfect airplane?) also do quite well. I think some approach 1200lbs UL.

Edited July 13, 2021 by Shadrach

[Scott Dennstaedt, PhD]

  On 7/12/2021 at 11:01 PM, EricJ said:

Some journals do this better than others, so like anything, one must consider the sources.   The reputable journals put a lot of effort into keeping the process working in order to maintain the reputation and attract quality papers. 

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The real value is looking at multiple sources on the same subject across differing journals.  I read over 250 accident studies in dozens of journals over the last 3.5 years.  I know many of these researchers personally (have met them, know their background, exchanged emails, spoke on the phone, etc.).  Their research differs in some cases, but that's just part of the natural process to understand the topic of interest. But if someone doesn't like the results of a particular study, my response to them is, "go do the study yourself."        

[Tim Jodice]

  On 7/13/2021 at 1:19 PM, Shadrach said:

It is not rare for vintage mid bodies to be well over 1000ul. It’s more the norm. Going through my W&B the lowest number I could find was 1046. I’m at 1059 now and could get more if I ditched the gen,  king center stack and remote compass.

The Encores (perfect airplane?) also do quite well. I think some approach 1200lbs UL.

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Agreed there are exceptions, the F model I fly has 1018UL. With the exception of some trainers most common light twins have 15-1600 UL.

[KLRDMD]

  On 7/14/2021 at 12:31 PM, Tim Jodice said:

With the exception of some trainers most common light twins have 15-1600 UL.

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My Barons/310 have all been between 1,650 and 1,775 lb useful load. My current 310 is 1,725. After the avionics upgrade I'm expecting it will be 1,750-1,775. And that's with full de-ice (boots, hot props and alcohol windshield). The 5,300 lb gross weight and wing loading of close to 30 really stood out yesterday as I flew home in the afternoon heat of Arizona, over the mountains. Subjectively the felt turbulence was probably 20% of what it would have been in a J/K Mooney.

[philiplane]

  On 7/13/2021 at 1:19 PM, Shadrach said:

It is not rare for vintage mid bodies to be well over 1000ul. It’s more the norm.

The Encores (perfect airplane?) also do quite well. I think some approach 1200lbs UL.

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I can put 900 pounds in the cabin of my early Aztec, and take full fuel (864 pounds), at 4800 GW.

I can put 1200 pounds in the cabin of my friend's C model Aztec, and still take 800 pounds of fuel at 5200 GW.

It's very hard to beat the versatility of these planes. They can do 1800 foot strips easily, and safely, yet still cruise at 165 to 180 knots. 

Caveat-they will not do it on 10 GPH like an M20F...everything in aviation is a compromise

Edited July 14, 2021 by philiplane

[Shadrach]

  On 7/14/2021 at 1:29 PM, philiplane said:

I can put 900 pounds in the cabin of my early Aztec, and take full fuel (864 pounds), at 4800 GW.

I can put 1200 pounds in the cabin of my friend's C model Aztec, and still take 800 pounds of fuel at 5200 GW.

It's very hard to beat the versatility of these planes. They can do 1800 foot strips easily, and safely, yet still cruise at 165 to 180 knots. 

Caveat-they will not do it on 10 GPH like an M20F...everything in aviation is a compromise

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All good points. By comparison, I can put 800lbs in the cabin of my F and go 500nm @150ish kts on ~35 gallons of fuel with VFR reserves. To me, that is a tremendous amount of output for the input. I’m not sure what does more or at least as much on so little.

[N201MKTurbo]

The big problem with twins is how long it takes to fill the fuel tanks...

 

From someone with a dead 310 engine for an avatar. 

Edited July 14, 2021 by N201MKTurbo

[KLRDMD]

  On 7/14/2021 at 4:50 PM, N201MKTurbo said:

The big problem with twins is how long it takes to fill the fuel tanks...

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It is about the same as filling the tanks on a Mooney Bravo or Rocket.

[rbridges]

  On 7/11/2021 at 3:36 AM, hammdo said:

I have personally experienced a single engine out (last May). My CFI and I followed the emergency procedures and when it was obvious she would not start up, we executed an off field landing. The biggest difference as mentioned would be a twin getting to an airport where I couldn't (we were still 5 miles from one).  Finding a good spot to land is key. Some places to land leave you with the lesser of two evils.

Just some context...

-Don

 

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That's the kicker.  We all know how to land, but at night or IMC, we may not know what we're landing into...

[N201MKTurbo]

  On 7/14/2021 at 4:53 PM, KLRDMD said:

It is about the same as filling the tanks on a Mooney Bravo or Rocket.

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The most I ever put in a Rocket was 108 gallons. The most I ever put in a 310 was 160 gallons. I haven't flown a 310 with locker tanks, what is that another 30 gallons? Brice's 310 has essentially two rocket motors on it. 

[KLRDMD]

  On 7/14/2021 at 5:11 PM, N201MKTurbo said:

The most I ever put in a Rocket was 108 gallons. The most I ever put in a 310 was 160 gallons. I haven't flown a 310 with locker tanks, what is that another 30 gallons? Brice's 310 has essentially two rocket motors on it. 

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Per hour of flying a Bravo, Rocket, Baron or 310 all burn pretty close to the same gallons of fuel (at least the way I fly each and I have flown all four and owned three of the four types mentioned) therefore a fill up of any of them will take about as long for a given flight.

[N201MKTurbo]

  On 7/14/2021 at 5:17 PM, KLRDMD said:

Per hour of flying a Bravo, Rocket, Baron or 310 all burn pretty close to the same gallons of fuel (at least the way I fly each and I have flown all four and owned three of the four types mentioned) therefore a fill up of any of them will take about as long for a given flight.

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I think you are in fuel denial....

Brice did tell me about a recent flight to Texas in the flight levels. He went LOP at 11 GPH a side and still trued out 190KTS That ain't bad, but it is still twice as much as a Rocket at the same altitude LOP at 11 GPH.

[KLRDMD]

  On 7/14/2021 at 5:27 PM, N201MKTurbo said:

I think you are in fuel denial....

Brice did tell me about a recent flight to Texas in the flight levels. He went LOP at 11 GPH a side and still trued out 190KTS That ain't bad, but it is still twice as much as a Rocket at the same altitude LOP at 11 GPH.

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I've owned 12 singles and six twins so I think I have their relative differences down.

[thinwing]

  On 7/14/2021 at 5:50 PM, KLRDMD said:

I've owned 12 singles and six twins so I think I have their relative differences down.

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thats pretty incredible...if youve been flying 20 years ,thats roughly one a year,flying 30 years ,one every 18 months ,40 years ,one every two years...I do know ,for me ,it took more than 2 years of ownership ,to really feel proficient