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markdavis(at)wbsnet.org
Guest

Posted: Tue May 03, 2011 6:11 pm Post subject: Tailslides

Dennis,

     Thanks for the clarification.



Mark Davis

N44YK



---

markdavis(at)wbsnet.org
Guest

Posted: Tue May 03, 2011 7:04 pm Post subject: Tailslides

Dennis,

      From my limited experience as a big sissy sitting on an ejection seat 

it was the higher backward velocity that had the most violent break and 

therefore the highest loads on the airframe, control surfaces and tiny blood 

vessels in my eyes.  It's those rides when you stay tail down longer than 

normal that make you say "OH SH!T!  This is going to be a good ride!"  One 

hand on the stick, one hand on the OH SHIT handle on the canopy bow.  I had 

to do an out of control ride in a Guppy as part of my instructor syllabus 

when I went back to wave A-4's in the training command.  I needed to do one 

more inverted spin so I went vertical and jammed the stick forward and cross 

controlled out of a tail slide.  Kind of a backward lomcevak.  The ensuing 

oscillations were violent enough to rip my seat pan out of the ejection seat 

and stick me in the top of the canopy so I got to do my recovery once I got 

my hands on the stick enough to establish positive G to get me off the roof! 

I told the T-2 IP in the front seat, Lloyd Prince, that we'd better knock it 

off because my seat pan wouldn't go completely back down in the seat.  Lloyd 

commented something about it taking me a little longer than usual to 

recover.  He told me I needed to do one more upright spin to complete the 

flight.  I'm not sure he completely understood why I didn't want to do any 

more OOC maneuvers.  An ejection with a cockeyed seat pan would have broken 

my back at the least.  After that flight I realized why the Guppies used for 

the Out of Control syllabus at VF-126 at Miramar had an additional 6" lap 

belt that the plane captain cinched down until it hurt then gave it one more 

tug!



Mark Davis

N44YK

---

wlannon(at)persona.ca
Guest

Posted: Tue May 03, 2011 7:54 pm Post subject: Tailslides

 	  Quote: 	
		  From my almost zero experience with tail slides I am really not qualified to 

comment on this.
	


But I do have one in my chequered past that I remember well.

It was about 1956 in my first "warbird", a Fairchild PT 26.  trying to teach 

myself the hammerhead (there were no aerobatic instructors back then).

The PT had about the same vertical penetration as a bowling ball and ran out 

of steam immediately.  Definitely an "OH SHIT" moment.

Full back stick with both hands and feet locked on the pedals.  The initial 

recover went well past the vertical before it was done.

No damage to me or the aircraft but I swore never to do that again.



Walt

---

mark.bitterlich(at)navy.m
Guest

Posted: Wed May 04, 2011 8:50 am Post subject: Tailslides

I need to answer your message Bill, and I don't think you are going to

life it very much.....  sorry. 



You say: "There must be a reason that so much conversation is generated

by this. Why would you want to do this during normal fun flying on a

clear beautiful day? Unless you have something to prove to yourself.

Cause  No one else will care. "



The conversation is being generated because there is a sense that an

operating capability of an aircraft is being questioned based on a

source that is undocumented, with no named author, and I object to that.

As to what aerobatic maneuvers I do, or anyone else does, and why they

do them, that is a personal decision and needs no justification to you

or anyone else.   



You say:  "If it says in the manual, don't do it."



Agreed!  However, I do not refer to a download from a web site as "A

MANUAL".   



"If you believe something else, have at it. Go by yourself so the

innocent don't get hurt or run risk of getting hurt."



AND THIS IS EXACTLY WHAT I AM TALKING ABOUT!  You can see ALREADY that

because someone has said:  TAIL SLIDES ARE UNSAFE IN A YAK AIRCRAFT,

that now we have people saying what Bill just said above.  It's a done

deal.  It's unsafe.  If you do it you're risking your life.  And don't

do it with anyone else in the aircraft!    



Not only is this gent saying HE is not going to do it, he is advising

OTHERS not to do it.  That is just wrong.  



"It's like paying taxes, the book says do it,"



What BOOK Bill?  Have you got a copy handy?  



"but there is always someone that pushes the envelope and tries to avoid

it. And in the end, a burial at sea."



I guess I will end up buried at Sea then... because I always push the

envelope which is why I fly a fully aerobatic aircraft.  If you don't

want to, then that's your decision, but since you seem to be questioning

mine... I will ask you... why in the world do you own a YAK if all you

are going to do is fly it straight and level?  



Take care, 



Mark Bitterlich



On May 3, 2011, at 11:15 AM, "Roger Kemp M.D." <viperdoc(at)mindspring.com>

wrote:



 	  Quote: 	
		   

<viperdoc(at)mindspring.com>
	


[quote] 

 The translated RU pilots' manual states for the novice to avoid them.

 No insinuation of experience made with this post. Just stating the

 recommendations made by the guys that had the most experience.

 Doc

 

 --

mark.bitterlich(at)navy.m
Guest

Posted: Wed May 04, 2011 8:50 am Post subject: Tailslides

Mark,



 Excuse me, but I am going to reply in kind to your email.  



First, I think there is a tad bit of difference in loads, airspeeds,

handling characteristics, etc., between a YAK-52 and MILITARY JET

AIRCRAFT.  Ya think?  That said, I am not attempting to exclude you from

the discussion by any means.  But..... What single engine prop aircraft

have you done tail slides in?  If 'none', that is ok too.   



Second, I have a ton of internet "references" myself on many subjects

pertaining to Yaks and other Russian Aircraft.  There is a tendency for

many people to list a reference to a web site and from then on treat it

as "The Real Deal".  This is one of the reasons why Wiki is no longer

allowed to be used as a reference in any "paper" that is produced

professionally, namely in college.  I am not saying you are doing this.

I am saying that unless I see a document written by the Russians who

built this airplane, I tend to look at it askance.  My reason for saying

this, is that in one sentence you refer to "Don't Do It" stuff listing

NATOPS on one hand, and a web site on the other.  The two are not the

same, nor should they be treated as such.   



You mention that you "seen some [tail slides] done that appear to create

a much higher than typical backward airspeed".  Me too.  Namely at

air-shows.  Done by aerobatic professionals with GOBS AND GOBS of

experience.  I am very careful to never equate what I have SEEN with

what I can DO.  Regardless, you talk about these circumstances as

creating an excessively high loads on control surfaces.  Ok, tell me how

you came to make that statement?  In other words, this is your opinion

based on what exact data?  Do you happen to have any accident data

available that corroborates control surface damage from tail slides?  If

we have an Aeronautical Engineer on the web site, please chime in.  



Excuse me, but I am not going to equate what you learned as a child, and

what you did in the military with Unlimited Level Aerobatic Maneuvers.

There are similarities of course, but they are not equivalent.  



You said: " So, after all that, I still would be interested in knowing

why SOMEONE deemed it apparently unsafe in a YAK 52 enough to include in

a POH."



NOTHING WRONG WITH THAT!  However, that does not mean that

someone/anyone should impose those limitations on others, or IMPLY that

those limitations should be imposed on others without REFERENCES.  And a

"reference" does not mean what someone ELSE wrote on the "Internet" or

was pulled off a web site.  



You said:  Anecdotal evidence that the maneuver has been performed

routinely without causing structural failure doesn't mean it hasn't been

exceeding load limits that someone, somewhere thinks is excessive."



So you are saying that if I write an article about how unsafe your car

is to drive, and you have been driving it for 10 years without any

problem what-so-ever, you will immediately stop driving it because I

wrote an article, without references, without proof, without anything

other than my opinion, that said your car is UNSAFE?  I think not. 



You said:  "If it came from someone in the design, manufacture, or

writing the initial operating limitations of the YAK 52 then I'm

interested."



YEP!  That's exactly the same thing that I said.  If this "apparent

limitation" on tail slides came from someone in the design, manufacture,

or writing of the initial operating limitations of the YAK-52, then I am

interested.  



What you seem to be saying is that you do not need this kind of reliable

source to believe a limitation (because

"someone/somewhere/sometime/somehow SAID it) but you DO need that kind

of reliable source to allow you to dismiss it.  And if that works for

you, I'm OK with that.  Just don't tell others that you think they

should think the same way.   



The closest source I have right now that I PERSONALLY BELIEVE (emphasis

on PERSONALLY) is someone who flew these EXACT AIRCRAFT in competition,

became the Russian National Aerobatic Champion in these aircraft, and

then was a TEST PILOT FOR SUKHOI, not to mention the United States

Unlimited Aerobatic COACH!  This man worked hand in hand with the

factory who made these aircraft in Russia.   Now if you have someone

MORE QUALIFIED than that, or a RUSSIAN MANUAL that talks about this,

please let me know.  

Mark

--

mark.bitterlich(at)navy.m
Guest

Posted: Wed May 04, 2011 9:15 am Post subject: Tailslides

Dennis, I am sorry to argue or debate with you in any way .. in public.

Once again, you know how much I respect your knowledge and abilities.  



There are many regulations, from many other CAA's, from many other

countries, concerning these aircraft.  I will NEVER, EVER refer to those

in a manner that implies that they should be imposed in this country.  



In that regard I refer to the many postings by Richard Goode that detail

"how lucky we are" to have the Experimental Category that we have here

in the United States, and the privileges' and freedoms that we have

because of it.  



Again... I respect your knowledge and opinions.  I have rarely (IF EVER)

disagreed with anything you have said, and I hope I continue to keep

that record clear, and that is NOT HAPPENING NOW.  Not really.  What we

basically have going on in this particular conversation is actually a

comparison between "your expert" and "my expert". 



You are welcome to believe your expert, and I am welcome to believe

mine.  Where we may come to a split in the road is when it starts

becoming a matter of what each of us believes is correct to advise OTHER

people to do. 



In this case, I will say that I am not trying to advise other people

what to do... one way or the other, and I don't think anyone else should

either.  



Until there is a document from the manufacturer of this aircraft that

discusses this issue in ANY way, it remains a matter of personal

perspective.  I believe people should make up their own minds and avoid

trying to tell others that they are wrong or unsafe.  



Let me give you a real world example.  The FAA in this country imposes

Operating Limitations on all Experimental Exhibition Aircraft.  My

UTVA-66 has FAA Operating Limitations that spell out CLEARLY that my

aircraft is not to be used for Glider Towing, or Parachuting.  The only

problem is that my UTVA-66 was equipped from the FACTORY for Glider

Towing and Parachuting with the doors off.  Does it mean because the FAA

has put these words into my Operating Limitations that my aircraft is

unsafe to tow a glider?  Nope.  But THIS countries "CAA" has said you

can't do it.   



Is the above a good example of what you are talking about?  Nope.  But

it does bring up the point that:  We don't know exactly what this CAA

said.  We don't know the REASON for why this particular CAA said this,

and it is still hear-say.  I have a Russian Flight Manual for the

YAK-50.  I have had it translated.  There is no flight restriction on

tail slides.  Period.  However, since this discussion mainly centers on

YAK-52, that is probably not relevant.  I do not fly YAK-52's.  



My best, 

Mark



   



--

dsavarese0812(at)bellsout
Guest

Posted: Wed May 04, 2011 10:16 am Post subject: Tailslides

Mark,

I have no problem with your comments whatsoever.  I do disagree with 

some of the words in your last paragraph where you say, "We don't know 

the REASON for why this particular CAA said this, and it is still 

hear-say."  We do know the reason, assuming it is fact in the first 

place.  I posted it in the email where I said the Lithuanian CAA has 

prohibited tail slides in Yak 52's.



Do I have a document from the Lithuanian CAA that says this?  Obviously, 

no I don't.  But I am working on trying to get documentation pertaining 

to this so-called prohibited maneuver.  If and when I get a copy of it, 

I'll post it to the list.  In the meantime, consider it only hearsay.

Dennis



On 5/4/2011 12:06 PM, Bitterlich, Mark G CIV Det Cherry Point, MALS-14 

64E wrote:

[quote] 



 Dennis, I am sorry to argue or debate with you in any way .. in public.

 Once again, you know how much I respect your knowledge and abilities.



 There are many regulations, from many other CAA's, from many other

 countries, concerning these aircraft.  I will NEVER, EVER refer to those

 in a manner that implies that they should be imposed in this country.



 In that regard I refer to the many postings by Richard Goode that detail

 "how lucky we are" to have the Experimental Category that we have here

 in the United States, and the privileges' and freedoms that we have

 because of it.



 Again... I respect your knowledge and opinions.  I have rarely (IF EVER)

 disagreed with anything you have said, and I hope I continue to keep

 that record clear, and that is NOT HAPPENING NOW.  Not really.  What we

 basically have going on in this particular conversation is actually a

 comparison between "your expert" and "my expert".



 You are welcome to believe your expert, and I am welcome to believe

 mine.  Where we may come to a split in the road is when it starts

 becoming a matter of what each of us believes is correct to advise OTHER

 people to do.



 In this case, I will say that I am not trying to advise other people

 what to do... one way or the other, and I don't think anyone else should

 either.



 Until there is a document from the manufacturer of this aircraft that

 discusses this issue in ANY way, it remains a matter of personal

 perspective.  I believe people should make up their own minds and avoid

 trying to tell others that they are wrong or unsafe.



 Let me give you a real world example.  The FAA in this country imposes

 Operating Limitations on all Experimental Exhibition Aircraft.  My

 UTVA-66 has FAA Operating Limitations that spell out CLEARLY that my

 aircraft is not to be used for Glider Towing, or Parachuting.  The only

 problem is that my UTVA-66 was equipped from the FACTORY for Glider

 Towing and Parachuting with the doors off.  Does it mean because the FAA

 has put these words into my Operating Limitations that my aircraft is

 unsafe to tow a glider?  Nope.  But THIS countries "CAA" has said you

 can't do it.



 Is the above a good example of what you are talking about?  Nope.  But

 it does bring up the point that:  We don't know exactly what this CAA

 said.  We don't know the REASON for why this particular CAA said this,

 and it is still hear-say.  I have a Russian Flight Manual for the

 YAK-50.  I have had it translated.  There is no flight restriction on

 tail slides.  Period.  However, since this discussion mainly centers on

 YAK-52, that is probably not relevant.  I do not fly YAK-52's.



 My best,

 Mark



 --

markdavis(at)wbsnet.org
Guest

Posted: Wed May 04, 2011 10:29 am Post subject: Tailslides

Mark,

     My only intention in entering this conversation on tailslides was to 

respond to the message posted by Grayson <grayson50(at)hotmail.com> asking "Is 

there any consensus on doing tailslides in the Yak-52?"  As I said, the POH 

that came with my YAK specifically excluded that maneuver.  I thought that 

he might want to be aware of that so he could make his own decision.  But, I 

also later qualified my reference to the POH with "albeit possibly in 

error".  Unfortunately there's a language barrier that makes it impossible 

for most of us to research original Russian manuals.  Hopefully Grayson has 

taken enough from the discussion to make his own decision, just like 

everyone else who's interested.  I hope Dennis can backtrack where he got 

the information for the POH on his website and resolve it for everyones' 

benefit and *possible* safety.



Fly safe, fly often and FLY NAVY!

Mark Davis

N44YK

---

mark.bitterlich(at)navy.m
Guest

Posted: Wed May 04, 2011 11:25 am Post subject: Tailslides

Thanks Dennis.  



You are correct.  



I'd like to see the exact Lithuanian CAA statements.  



That said, all of us... you, me, and every other Experimental Exhibition

Aircraft owner OUT there in the United States, needs to be EXTREMELY

careful of what we say regarding our "obligation" to abide by orders

from Foreign CAA's.  Paying attention to them, and making careful and

thought worthy decisions based on them ... YES.  ABIDING by them as if

they are SACROSANCT...   NO!  

Think I am wrong about this?  And this is not directed at you Dennis,

but EVERY READER out there, then fine... 



Consider this:  When your M-14 engine reaches about 500 hours, remove it

from your airplane and send it in to be over-hauled.  Because gents,

that is what the Russians did and there is no end to the manuals and

books that require it.  Certain CAA's from certain foreign countries

ALSO require it.  There are also a lot of CAA's out there that OUTLAW,

PROHIBIT, DENY the option of putting automotive conversion spark plugs

and wires on M-14 engines as well.  Because they deem them to be UNSAFE.

U N S A F E !! 



But we know that to be wrong and we know that the automotive plug and

conversion kit offered (by Dennis for example) are EXTREMELY safe, and

actually grossly IMPROVES the operation of the engine and its overall

reliability.  I love it and have it on my own airplane.  Can't do it in

England though.  Their CAA says it is not allowed.  



This is where I am going with ALL of this.  Or at least some of it.  



Mark

--

cjpilot710(at)aol.com
Guest

Posted: Wed May 04, 2011 11:25 am Post subject: Tailslides

This discussion of tail slides has been real  interesting.  It points a problem  that both Dennis and Mark have so apply pointed out.  The real documentation of limits vs  practices.  I owned a Varga Kachina  for a number of years.  I found that  it looped and rolled nicely.  One  day (by-my-self) I spun it.  It did  it beautifully.  Oooops I THAN read  the placard â€œNo Spins Allowedâ€.  My  curiosity got me and I called the factory direct, and asked for the  engineer.  Small company way back  than- got right to the man.   I  asked why the Kacahina wasn't certified for acrobatics?  His answer was not a structural limited  but the airplane had a â€œpro unrecoverable flat spin character particularly with  the CG near the aft limitedâ€.  So  there you go.  I often spun the  Kachina BUT only with me in it and no one in the back seat.  Sweet little airplane. 

I would not try to tail slide a CJ-6.  Not that it might not do one  aerodynamically, but I look at the structure of the tail and from my experience  though the years, comparing it to similar aircraft, it â€œlooksâ€ to light to take  a lot of back loads.  This has  nothing to do with the fabric covering, but the very structure its self.  Plus weâ€™ve had a number of issues with  different CJs out there with cracked horizontal stabilizers front spars at the  hole for the elevator cable. 

Plus I think we need to analyze a true â€˜tail slideâ€™ vs a  â€˜wipe stallâ€™.  Not the aerobatic pro  here, a true tail slide requires enough power to maintain aircraft control  inputs to hold the aircraft in a vertical position but not enough to maintain  altitude (hover) so that it drops controlled along its vertical flight  path.  Thus there is positive  pressure on the flight controls (at least the tail anyway) until the airplane  either rights itself or the pilots recovers. 

A â€˜wipe stallâ€™ is quite different.  The airplane never has enough power or  the throttle is closed and the airplane starts to fall.  At some very early point the aerodynamic  loads from reverse airflow will start having an effect on the controls.  Here is where its get dangerous.  If the pilot holes the controls â€˜rock  hardâ€™ in the natural position, the airplane will NOT slide backward  indefinitely.  It will pick itâ€™s own  way to recover.  The pilots control  input can determine which way that accrues.  It is the uncontrolled rapid movement of  rudder and elevators against their stops where the damage can happened.  Here is where I think the CJ has its  limits. 

When I do hammerhead turns in the CJ, I donâ€™t wait for  the stop point like I did in my Pitts.   While still in forward flight, I â€œmotorâ€ her around quite early and I  make sure that I have a good hold of the stick/rudder.  I have inadvertently done wipe stalls in  the CJ and quite frankly she is very benign and predicable, BUT I am gun-shy of  the tail structure. 

I have not look at the structural difference between the  52 vs 50.  While the 50 is defiantly  lighter and there is very little difference in overall shape, it would be  interesting to â€œfine the truth so to speakâ€. 

Jim "Pappy" Goolsby 

  In a message dated 5/4/2011 1:16:19 P.M. Eastern Daylight Time,  mark.bitterlich(at)navy.mil writes:

 [quote]-->    Yak-List message posted by: "Bitterlich, Mark G CIV Det Cherry Point, MALS-14    64E" <mark.bitterlich(at)navy.mil>

Dennis, I am sorry to argue or    debate with you in any way .. in public.

Once again, you know how much I    respect your knowledge and abilities.  

There are many    regulations, from many other CAA's, from many other

countries, concerning    these aircraft.  I will NEVER, EVER refer to those

in a manner that    implies that they should be imposed in this country.  

In that    regard I refer to the many postings by Richard Goode that detail

"how lucky    we are" to have the Experimental Category that we have here

in the United    States, and the privileges' and freedoms that we have

because of it.     

Again... I respect your knowledge and opinions.  I have rarely    (IF EVER)

disagreed with anything you have said, and I hope I continue to    keep

that record clear, and that is NOT HAPPENING NOW.  Not    really.  What we

basically have going on in this particular    conversation is actually a

comparison between "your expert" and "my    expert". 

You are welcome to believe your expert, and I am welcome to    believe

mine.  Where we may come to a split in the road is when it    starts

becoming a matter of what each of us believes is correct to advise    OTHER

people to do. 

In this case, I will say that I am not trying    to advise other people

what to do... one way or the other, and I don't    think anyone else should

either.  

Until there is a document    from the manufacturer of this aircraft that

discusses this issue in ANY    way, it remains a matter of personal

perspective.  I believe people    should make up their own minds and avoid

trying to tell others that they    are wrong or unsafe.  

Let me give you a real world example.     The FAA in this country imposes

Operating Limitations on all Experimental    Exhibition Aircraft.  My

UTVA-66 has FAA Operating Limitations that    spell out CLEARLY that my

aircraft is not to be used for Glider Towing, or    Parachuting.  The only

problem is that my UTVA-66 was equipped from    the FACTORY for Glider

Towing and Parachuting with the doors off.     Does it mean because the FAA

has put these words into my Operating    Limitations that my aircraft is

unsafe to tow a glider?  Nope.     But THIS countries "CAA" has said you

can't do it.   

Is    the above a good example of what you are talking about?  Nope.     But

it does bring up the point that:  We don't know exactly what this    CAA

said.  We don't know the REASON for why this particular CAA said    this,

and it is still hear-say.  I have a Russian Flight Manual for    the

YAK-50.  I have had it translated.  There is no flight    restriction on

tail slides.  Period.  However, since this    discussion mainly centers on

YAK-52, that is probably not relevant.  I    do not fly YAK-52's.  

My best,    

Mark

-----Original    Message-----

From:    owner-yak-list-server(at)matronics.com

[mailto:owner-yak-list-server(at)matronics.com]    On Behalf Of A. Dennis

Savarese

Sent: Tuesday, May 03, 2011 8:51    PM

To: yak-list(at)matronics.com

Subject: Re: Re:    Tailslides

--> Yak-List message posted by: "A. Dennis    Savarese"

<dsavarese0812(at)bellsouth.net>

The Yak manual you    speak of is on my web site and was given to me about 

13-14 years ago by a    gentleman who is a CFI and was trained in Russia by

Russian    pilots.  He extracted, translated and condensed the information 

from    the original Russian flight manual and from the instructors who 

trained    him.

I think my only point is, regardless of who says it's OK or who    says 

it's not OK is the fact that a government Civil Aviation    Administration 

(CAA) has prohibited tail slides in Yak 52's.  There    has to be something

behind this prohibition, assuming it is true.     Now if I can find 

substantiating documentation, I will share that with the    group.

Dennis

On 5/3/2011 7:00 PM, Mark Davis wrote:

 	  Quote: 	
		      --> Yak-List message posted by: "Mark Davis"    <markdavis(at)wbsnet.org>

 Mark,

 Now I know    where I'd seen the prohibition on tail slides before.... in

 the POH    for my YAK. I found an online copy that is the same as the one

 that    came with N44YK. I'm not sure who generated it or if it is

correct.

 	  Quote: 	
		      I'm sure tailslides have been done safely in YAK 52's by many    for

years,

 	  Quote: 	
		   but I'm still curious why they are listed as prohibited    on page 10 of

 this POH. The link follows:

    www.yak-52.com/downloads/?YAK52%20POH.doc

 My copy of the above    manual doesn't have the question marks in

 parenthesis like the link    above shows. Maybe Dennis knows the origin

of

 	  Quote: 	
		   the    manual.

 Oh... for the record, so I can participate in the    discussion, I have

 done tail slides in several aircraft (TA-4J and    T-2C), just not in one

 that has the maneuver prohibited in it's POH    (EA-6B NATOPS/SOP and my

 YAK-52 POH albeit possibly in error). Must be    my Navy flight training

 that makes me heed the "don't do it"    stuff.

 As for the tailslides themselves, I've seen some done    that appear to

 create a much higher than typical backward airspeed.    Whether by luck

(my

 	  Quote: 	
		   case) or skill (Sergei Boriak) those would be    the ones that would

impart

 	  Quote: 	
		   a potentially damaging load on control    surfaces. As for your question

 "Which is higher? Tail Slide Air Loads,    or Snap Roll Air Loads? Well,

 you tell me", my simple mind goes back    to learning as a small child

that

 	  Quote: 	
		   it wasn't a good idea to stick    your hand out of the window of a car at

 80 mph fingers pointing    forward then deflecting your hand contrary to

 the prevailing wind.    Nearly getting my shoulder yanked out of the

socket

 	  Quote: 	
		   taught me that    fairing your hand downwind put a less rapid load on my

 joints. Back to    my flight training....don't yank on the G (or rolling

    pulls).

 So, after all that, I still would be interested in    knowing why SOMEONE

 deemed it apparently unsafe in a YAK 52 enough to    include in a POH.

 Anecdotal evidence that the maneuver has been    performed routinely

 without causing structural failure doesn't mean it    hasn't been

exceeding

 	  Quote: 	
		   load limits that someone, somewhere thinks is    excessive. If it came

from

 	  Quote: 	
		   someone in the design, manufacture, or    writing the initial operating

 limitations of the YAK 52 then I'm    interested.

 Thanks for your input. I enjoy the    discussion.

 Mark Davis

 N44YK

 -----    Original Message ----- From: "Bitterlich, Mark G CIV Det Cherry

 Point,    MALS-14 64E" <mark.bitterlich(at)navy.mil>

 To:    <yak-list(at)matronics.com>

 Sent: Tuesday, May 03, 2011 3:18    PM

 Subject: RE: Re: Tailslides

>    --> Yak-List message posted by: "Bitterlich, Mark G CIV Det    Cherry

> Point, MALS-14 64E"    <mark.bitterlich(at)navy.mil>

>

> Ok, let's talk    conjecture, just for the fun of it.

>

> When an aircraft    flies backwards in a tail-slide, what is the

estimated

 	  Quote: 	
		  > speed    and airflow over the control surfaces as it makes the reverse?

> Any    thoughts on that? Before we talk about it, let's limit this

>    discussion please to pilots who have actually performed    tail-slides

in

 	  Quote: 	
		  > any make or model of    aircraft.

>

> Now. How about a snap roll. What are the    speed and flow forces (that

> would be AIR LOADS) over the control    surfaces themselves when an

> aircraft performs an accelerated snap    roll. Let's focus on elevator

and

 	  Quote: 	
		  > rudder    please.

>

> Which is higher? Tail Slide Air Loads, or Snap    Roll Air Loads? Well,

> you tell me.

>

> The air    load on the control surfaces during a tail slide are

backwards.

 	  Quote: 	
		  >    Does this make them higher? We are talking about the actual    pressure

> induced air loads on the surfaces of these controls.    Remember that

> speed through the air during a tail slide is in    reality very slow as

> compared to normal    flight.

>

> How about bending moments? Are they higher    during a tail-slide, or

are

 	  Quote: 	
		  > they higher during a 9 G pull at    150 knots? We're talking about when

> everything is done    CORRECTLY!

>

> On the other hand.... what happens if you    manage to get into a good

tail

 	  Quote: 	
		  > slide and then just "let go" of    the stick? The result is that it will

> SLAM with a very large    degree of force right into the control stop.

> Anything hooked to    the elevator when this happens... such as a

> COUNTER-WEIGHT is    going to have a HUGE instantaneous load. HUGE.

>

> Would    it be possible to mismanage the aircraft to such a    large

degree,

 	  Quote: 	
		  > then LET go of the stick, and ALLOW it to SLAM    into the stop, and

when

 	  Quote: 	
		  > that happened, would it BE POSSIBLE to    incur some type of mechanical

> failure? Yep... I do believe that is    possible, and it can happen if

the

 	  Quote: 	
		  > pilot is not prepared for    the forces that can happen in advance!

>

> That said, I    fully agree that it is entirely possible for a pilot to

put

 	  Quote: 	
		  > an    aircraft into a situation where it exceeds its design limits and

>    something breaks.

>

> I have watched tail-slides being    taught in a YAK-52. I have performed

> tail-slides in a YAK-50. I    disagree with anyone that says that the

YAK

 	  Quote: 	
		  > model aircraft is    not safe to do tail-slides... politely and

> respectfully disagree.    The expert I believe in is my aerobatic coach.

> Who anyone else    believes is their own personal choice and I respect

that

[quote]> too.    If you have doubts, THEN DO NOT DO THEM!

>

> Mark    Bitterlich

>

>

>    --

mark.bitterlich(at)navy.m
Guest

Posted: Wed May 04, 2011 11:29 am Post subject: Tailslides

Understood. 



Good answer.  



To be clear, I want to see a Russian Manual that says tail slides are

unsafe in YAK-52's.  



Failing that, I want a person who has or had, direct contact with the

factory that built them.  It would be nice if that person also had VAST

experience in flying them and teaching others to fly in them as well.  



I have that.  Which is why I put in my 2 cents as well for Grayson to

consider.  



Take care,



Mark Bitterlich 



--

viperdoc(at)mindspring.co
Guest

Posted: Wed May 04, 2011 11:45 am Post subject: Tailslides

The manuals were first distributed by Wess Crowder as he was importing YAK's

brand new in the box from his source in RU. It came with the Russian

translated POH bound with a leather cover and the monofilament line binding

the paper. The one Dennis has on his website is a reproduction of one of

those manuals. I have a printed version of that manual. Scott Patterson has

the one of the original POH's from Wes Crowder since he bought his YAK

directly from Wes  around 1995. 

The manual states  as "Prohibited maneuvers...tailslides."

Doc



--

mark.bitterlich(at)navy.m
Guest

Posted: Wed May 04, 2011 12:00 pm Post subject: Tailslides

Exactly. 



Mark



--

mark.bitterlich(at)navy.m
Guest

Posted: Wed May 04, 2011 12:14 pm Post subject: Tailslides

Interesting.  



My YAK-50 was Wes Crowder's test aircraft for a lot of his

modifications.  I have the original Russian Manual.  I had it translated

by a Russian and written down line by line.  



No tail slide restrictions.  Might be a translation thing?  



Sorry. 



Mark

--

radiopicture

Joined: 23 Jun 2008
Posts: 263

Posted: Wed May 04, 2011 12:14 pm Post subject: Tailslides

Other countries notwithstanding, my understanding is that the reason we don't have standard airworthiness certificates for these airplanes in the USA is because they were not certified here for whatever reason (usually no economic reward for doing so). In order to to have permission to fly them we have a lot of restrictions, and the only requirement we must fulfill in terms of the hardware itself is that it passes a condition inspection. The extra risk inherent in this arrangement is the reason for the restrictions. The reason things like the automotive plug conversion are allowed is because the airplane as a whole is no more certified than the modification, so there's really no airworthiness standard to be diminished. 



As we know, the Russian way of doing things is different than ours, and not all of it translates to our system. Therefore it's up to us, with the help of the experts we rely on, to keep our own keysters intact. IMHO, the random application of the rules that were intended for aircraft with standard airworthiness certificates to our planes would be improvisational, overzealous and incorrect on the part of regulatory officials. I am sincere in saying that my local FSDO has never abused their authority or done anything else than try to get my Yaks properly documented. Yes, I feel lucky.



Having said all of this, my philosophy has been to first find out how the Russians did it. This is partly because I'm not as qualified as some to deviate from the stock airplane. However, even in my case, deviations are warranted. Let's face it: We can't conform to the rules meant for spam cans and their drivers, even if we were inclined to. 

On May 4, 2011, at 3:18 PM, Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E wrote:



[quote] 

 

 Thanks Dennis.  

 

 You are correct.  

 

 I'd like to see the exact Lithuanian CAA statements.  

 

 That said, all of us... you, me, and every other Experimental Exhibition

 Aircraft owner OUT there in the United States, needs to be EXTREMELY

 careful of what we say regarding our "obligation" to abide by orders

 from Foreign CAA's.  Paying attention to them, and making careful and

 thought worthy decisions based on them ... YES.  ABIDING by them as if

 they are SACROSANCT...   NO!  

 

 

 Think I am wrong about this?  And this is not directed at you Dennis,

 but EVERY READER out there, then fine... 

 

 Consider this:  When your M-14 engine reaches about 500 hours, remove it

 from your airplane and send it in to be over-hauled.  Because gents,

 that is what the Russians did and there is no end to the manuals and

 books that require it.  Certain CAA's from certain foreign countries

 ALSO require it.  There are also a lot of CAA's out there that OUTLAW,

 PROHIBIT, DENY the option of putting automotive conversion spark plugs

 and wires on M-14 engines as well.  Because they deem them to be UNSAFE.

 

 

 U N S A F E !! 

 

 But we know that to be wrong and we know that the automotive plug and

 conversion kit offered (by Dennis for example) are EXTREMELY safe, and

 actually grossly IMPROVES the operation of the engine and its overall

 reliability.  I love it and have it on my own airplane.  Can't do it in

 England though.  Their CAA says it is not allowed.  

 

 This is where I am going with ALL of this.  Or at least some of it.  

 

 Mark

 

 

 --

GeorgeCoy

Joined: 02 Dec 2010
Posts: 310

Posted: Wed May 04, 2011 12:21 pm Post subject: Tailslides

Kind of reminds me of the Shakespearean play .... you guessed it a comedy: "Much Ado About Nothing"



--

mark.bitterlich(at)navy.m
Guest

Posted: Wed May 04, 2011 12:54 pm Post subject: Tailslides

I wish I had written all that.  Really an excellent analysis Eric.  



Let me add one thing. 



You said: "IMHO, the random application of the rules that were intended

for aircraft with standard airworthiness certificates to our planes

would be improvisational, overzealous and incorrect on the part of

regulatory officials."  



You then said:  " Yes, I feel lucky "



YOU ARE VERY VERY LUCKY INDEED ERIC!  And just because it might be "

improvisational, overzealous and incorrect ", does NOT mean that someone

in the name of safety might decide to do EXACTLY THAT.  In fact, IMHO,

'someone' already is.    



Mark



--

jan.mevis(at)informavia.b
Guest

Posted: Wed May 04, 2011 1:11 pm Post subject: Tailslides

Well, whatever you do with a Yak or a Nanchang, as long as you don't end up in a hole in the ground ...



There have been too many accidents recently, for whatever reasons. Most of the time, but unconfirmed, pilot's error, unfortunately.



You won't find any precise Russian manuals describing what to do in this or that case, simply because there was no need to write that kind of manuals back in the Soviet time: a pilot obeyed the orders from his instructors. That's it. All other stuff has been written AFTERWARDS and as Mark indicates, is not authoritative.



To keep our Yaks flying: don't push them to the edge.

The 52's nor the 50's can be considered being competitors for today's aerobatics. THEY ARE OLDTIMERS!!!!!



Fly them as an oldtimer. You can do some nice basic aerobatics without pushing them to the edge. It hurts when you push an oldtimer as if it were a youngster.



Formation flying - with the proper instruction!!!!!!!! - is nice. 



Only my 2 cents,



Jan



Yak 50 RA2005K

Yak 52 RA1453K



[quote] --

tigeryak18t

Joined: 26 Sep 2009
Posts: 233
Location: PARIS FRANCE

Posted: Wed May 04, 2011 1:18 pm Post subject: Tailslides

Hey Yak people,

speaking is fine around a glass of beer...

Did anyone considered asking the Yakovlev Design Bureau in Moscow????

Whatever anyone can say if nothing happens all is well, but if there is an accident due to a tailslide, then the justice will ask Yakovlev Design Bureau

  Then it will be their answer which will count.

So let's ask Yakovlev Design Bureau......that's probably the best move.



Best



2011/5/4 George Coy <george.coy(at)gmail.com (george.coy(at)gmail.com)>

  [quote]--> Yak-List message posted by: "George Coy" <george.coy(at)gmail.com (george.coy(at)gmail.com)>

   

 Kind of reminds me of the Shakespearean play .... you guessed it a comedy: "Much Ado About Nothing"

 

 --

_________________
Didier Tiger YAK18T
Member of Commemorative Air Force
French Wing

GeorgeCoy

Joined: 02 Dec 2010
Posts: 310

Posted: Wed May 04, 2011 1:27 pm Post subject: Tailslides

B.T.W. that is LES Crowder. 



--

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