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dlm46007(at)cox.net
Guest

Posted: Wed Jun 11, 2008 6:39 pm Post subject: Emailing: sb08-6-1[1]

This is what I found about an hour ago. Look at the end of the pdf.

sb08-6-1[1].pdf

Description:

Download

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sb08-6-1[1].pdf

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385.76 KB

Downloaded:

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Dave(at)AirCraftersLLC.co
Guest

Posted: Wed Jun 11, 2008 7:39 pm Post subject: Emailing: sb08-6-1[1]

Well no wonder--it's the one with the Continental 



Seriously, if that's what we're looking for, that area is visible through

the aft inspection plates.



Dave Saylor

AirCrafters LLC

140 Aviation Way

Watsonville, CA 

831-722-9141

831-750-0284 CL

www.AirCraftersLLC.com

Do Not Archive 



--

rv10(at)sinkrate.com
Guest

Posted: Wed Jun 11, 2008 8:04 pm Post subject: Emailing: sb08-6-1[1]

A few observations...



1) Is the doubler going to be thick/strong enough to keep that from

happening?  That's a pretty hefty crack.  Seems the crack will just be on

the edge of the doubler if things are moving around that much.  Antenna

doublers are supposed to be secured along 3 sides.



I'm wondering if the rib was "forced" into position possibly installed with

a bit of a bending load on it?



2) The J-Channel is contacting the bulkhead...  Didn't we just discuss this?



3) I won't mention the nice long, uniform scratches in the side skin.



4) Anyone know what the pop rivets in front of the F-1010 are.... data

plate?



4) I'm with Dave... must be the Continental 



--

rv10(at)sinkrate.com
Guest

Posted: Wed Jun 11, 2008 8:06 pm Post subject: Emailing: sb08-6-1[1]

Oops forgot my name on the last one...



Ben Westfall

#40579



--

dlm46007(at)cox.net
Guest

Posted: Wed Jun 11, 2008 8:33 pm Post subject: Emailing: sb08-6-1[1]

I doubt it was the engine. I just talked with someone who flew the 220

version for transition training September 2007. He squawked the aircraft for

inadequate up trim. I have flown the 540 version for 33 hours and never

gotten the trim setting more than 2 bars from neutral. Inadequate up trim

suggest to me that a improperly rigged trim system might have the two

elevator halves fighting each other and twisting the elevators and stressing

the horizontal stab. 



--

daveleikam(at)wi.rr.com
Guest

Posted: Wed Jun 11, 2008 9:36 pm Post subject: Emailing: sb08-6-1[1]

After looking closely at the pictures, it appears that the metal is not only 

cracked, but also "crinkled."  If you look at the skin to the left of the 

crack, it appears to also be deformed which concurs with the failure of the 

bulkhead.   First thought is there was substantial down pressure 

(compression) on the longeron and on the F1010A angle at this point. 

Except when rolling, would there ever be uneven force on the HS?   And even 

then I would think the forces would be very little.  Would it be possible to 

detect equal tensional stress on the other side?



I agree with the twisted HS theory.



Dave Leikam

#40496  N89DA (Reserved)

Muskego, WI

- Original Message ----- 

From: "David McNeill" <dlm46007(at)cox.net>

To: <rv10-list(at)matronics.com>

Sent: Wednesday, June 11, 2008 11:29 PM

Subject: RE: Emailing: sb08-6-1[1]

[quote] 



 I doubt it was the engine. I just talked with someone who flew the 220

 version for transition training September 2007. He squawked the aircraft 

 for

 inadequate up trim. I have flown the 540 version for 33 hours and never

 gotten the trim setting more than 2 bars from neutral. Inadequate up trim

 suggest to me that a improperly rigged trim system might have the two

 elevator halves fighting each other and twisting the elevators and 

 stressing

 the horizontal stab.



 --

Deems Davis

Joined: 09 Jan 2006
Posts: 925

Posted: Wed Jun 11, 2008 10:13 pm Post subject: Emailing: sb08-6-1[1]

Dave, i agreeI

If folks take the time and go back through the archive and read the 

original posts  (12/06) which witnessed the 'twist' and the follow on 

discussion regarding the Elevator trim rigging and how  following Van's 

plan instructions, can and will result in a twisted HS. the situation 

described there is entirely consistent with the results depicted in the 

picture of the crack. I believe that there is a VERY high likelihood 

that the root cause of the crack lies in a twisting moment induced by 

the asynchronous movement of the elevator trim tabs. I was the individ 

David refers to that flew 220RV late last year, and there was not enough 

up elevator trim available to take the significant back pressure off the 

elevator during landings. I believe this is also consistent with the 

trim rigging and twisting explanation. Here's an excerpt from my post 

following transition training.

**This brings up the next point and that is elevator authority. N220RV had 

NO balast in the rear when we flew.  We initiated our approach with 20 

degrees of flaps (second detent), Turning downwind we added full flaps. 

With full flaps there is NOT enough trim to take the back pressure off 

of the stick. I found that the back pressure was much more than I found 

comfortable, and flew some landings with 2 hands! Makes it 

difficult/impossible to develop a fingertip feel on landings.  The other 

item has been reported by several others and that is when landing it  

takes the full aft movement of the stick. The topic has been discussed & 

debated previously, but in my opinion with only 2 people  and no  

baggage/balast  there is not enough elevator. Towards the end of 8.1 

hours,  I was able to get some of the rust scrubbed off, got a little 

less shy about the rapidly approaching ground, and found a way to  

'muscle' a couple of good landings. then Mike says " let me show you 

something, .... we took another trip around the pattern flew exactly as 

before only on our base leg after extending full flaps, he had me 'blip' 

off a degree or two of flap at a time until the back pressure I'd grown 

unaccustomed to holding was gone..... then flew the rest of the landing 

!!!!! WOW!!! what a difference  !!!!!  Mike why did you keep this little 

secret to the end??????? the plane landed almost identical to full 

flaps, but the 'feel' was completely different and actually a joy!!!!!**

Dave Leikam wrote:

[quote] 

 After looking closely at the pictures, it appears that the metal is 

 not only cracked, but also "crinkled."  If you look at the skin to the 

 left of the crack, it appears to also be deformed which concurs with 

 the failure of the bulkhead.   First thought is there was substantial 

 down pressure (compression) on the longeron and on the F1010A angle at 

 this point. Except when rolling, would there ever be uneven force on 

 the HS?   And even then I would think the forces would be very 

 little.  Would it be possible to detect equal tensional stress on the 

 other side?

 I agree with the twisted HS theory.

 Dave Leikam

 #40496  N89DA (Reserved)

 Muskego, WI

 - Original Message ----- From: "David McNeill" <dlm46007(at)cox.net>

 To: <rv10-list(at)matronics.com>

 Sent: Wednesday, June 11, 2008 11:29 PM

 Subject: RE: Emailing: sb08-6-1[1]

> 

>

> I doubt it was the engine. I just talked with someone who flew the 220

> version for transition training September 2007. He squawked the 

> aircraft for

> inadequate up trim. I have flown the 540 version for 33 hours and never

> gotten the trim setting more than 2 bars from neutral. Inadequate up 

> trim

> suggest to me that a improperly rigged trim system might have the two

> elevator halves fighting each other and twisting the elevators and 

> stressing

> the horizontal stab.

>

> --

msausen

Joined: 25 Oct 2007
Posts: 559
Location: Appleton, WI USA

Posted: Thu Jun 12, 2008 3:52 am Post subject: Emailing: sb08-6-1[1]

That was the first thing I noticed too.  It certainly looks like the cracks were induced from a repeated compression and release of bulkhead in that area.  Doublers may only be a band aid for this and I bet we will see more of these as the fleet gain hours.  If it really is being partially caused by asymmetric trim tab loading, seems like someone could come up with a mod fairly quickly.  I know I'll be looking at the trim servo setup while I have it off.



Michael



--

bcondrey

Joined: 03 Apr 2006
Posts: 580

Posted: Thu Jun 12, 2008 5:10 am Post subject: Emailing: sb08-6-1[1]

Interesting.  When I flew with Alex D. for my transition training he

carried 2 cases of oil in the baggage area in his IO-540 bird.  Also, he

said that he normally lands with half flaps (he has a flap positioning

system) unless there are rear seat passengers.  When only front seat

occupants there is a very noticeable nose down pitching when going from

half to full flaps.



Bob



--

Tim Olson

Joined: 25 Jan 2007
Posts: 2881

Posted: Thu Jun 12, 2008 6:20 am Post subject: Emailing: sb08-6-1[1]

This just proves how individual these airplanes will be, based

on equippage.   N220RV has a LIGHTER engine than the IO-540,

so if N220RV ran out of elevator, something probably really

wasn't right to begin with.  I remain skeptical that following

the plans will absolutely result in a twisted tail.  I've looked

back on many flights, and even during stall buffet, and watched

the tail.  On my last flight, both elevator horns were about 1/4"

up in cruise, but they were symmetrical. And now for the best

part.  I have zero problems trimming my stick for 100% hands

off flight, with full flaps, and a 70kt approach speed.  I

actually take most people who are NON-pilots who want to learn,

and show them that their job is to trim to the approach airspeed,

and that at that point, releasing their hand from the stick, or

only touching with fingertips, is what they want to do to test

for good trim.   And I show them that if you just put your hands

down for a sec, the plane flies just fine.



So while I do get intrigued by the reports people give of other

RV-10's running out of nose-up trim, or reports of twisted

tails, I'm not really sure I will believe that doing it the

plans way is the cause.  I think these planes are naturally

so diverse in layout and weighting and design that you're just

seeing that natural variation.   For instance, N220RV is

a pretty stripped down plane, built by Vans.  Alex's RV-10

is a John Nys plane equipped with A/C, and we've got people

building with extreme variations in engine choice, battery

positions and quantities, propellers, builder attention to

detail, and builders ability to follow plans.



One other thing to keep in mind is that some planes only have

trim tabs on one side, so our asymmetric trim isn't necessarily

that odd.  But, that said, wouldn't it be cool if there was

a trim servo mechanism mod that did allow both tabs to provide

the same nose down and nose up trim amounts, while being

symmetrical.



As far as "the Fix" goes, I'm mixed on that one too.  It does

look like perhaps there was a little compression to the

bulkhead, but also that perhaps that bulkhead was pushed

forward or aft, twisting slightly.  And when you see that the

patch is just another layer of metal over that area, it kind

of makes me wonder why that patch just won't do it again.

it seems that you'd want it to attach to the side skin, and

especially that you'd want to prevent any movement relative

to the longeron, of that top angle of aluminum.  Then again,

you don't always want complete stiffness, so maybe that's

part of it too.



I'll do the SB as planned but still watch to see what they

come up with next.  As far as trim goes though, I just don't

see a problem in my particular plane, with how the trim

functions, built per plans.



Tim Olson - RV-10 N104CD - Flying

do not archive

Condrey, Bob (US SSA) wrote:

[quote] 

 

 Interesting.  When I flew with Alex D. for my transition training he

 carried 2 cases of oil in the baggage area in his IO-540 bird.  Also, he

 said that he normally lands with half flaps (he has a flap positioning

 system) unless there are rear seat passengers.  When only front seat

 occupants there is a very noticeable nose down pitching when going from

 half to full flaps.

 

 Bob

 

 --

bcondrey

Joined: 03 Apr 2006
Posts: 580

Posted: Thu Jun 12, 2008 6:57 am Post subject: Emailing: sb08-6-1[1]

Tim,



You bring up a good point about configuration differences.  There is a

lot of focus on empty weight but equally important is where the empty

weight CG winds up.  



Regarding Alex's plane - Although John N. built it (but didn't do the

finish work), the airframe itself is in a stock configuration and

doesn't have some of the telltale signs of being built by John N. (i.e.

second set of fuel tanks outboard).  That plane does have AC and a heavy

looking interior but even with full flaps on approach there's plenty of

trim authority, he just prefers half flaps.



Regarding comments from Deems, it seems strange that with the small

continental up front that you'd still have a CG in the forward part of

the envelope.  I've never flown that plane but do have the numbers from

410RV and its empty weight ARM is at 106.99".  You'd think with a

lighter engine that the CG would be a little farther aft



I also notice that your empty weight Arm is 108.67" (from your POH) and

mine is 108.20" which makes a huge difference in the handling feel.  



See you Saturday at BNW!



Bob

--

rene(at)felker.com
Guest

Posted: Thu Jun 12, 2008 7:19 am Post subject: Emailing: sb08-6-1[1]

On the trim issue.  My empty weight CG is aft of 410RV.  During transition

training with no ballast in 410RV I ran out of trim on landing with full

flaps.  On my airplane I have plenty of trim and always land full flaps.  



Rene' Felker

RV-10 N423CF Flying

801-721-6080

--

Tim Olson

Joined: 25 Jan 2007
Posts: 2881

Posted: Thu Jun 12, 2008 7:23 am Post subject: Emailing: sb08-6-1[1]

Exactly....lots of differences.  Just pointing out that between

all of the planes there are significant equipment differences.

For me, I've been a pretty firm believer that you should not

TRY to "fix" the "noseheavy problem" any more than by doing

things that are natural to your design, because it will be very

easy to go overboard with moving that CG aft.  I have a PC925,

and have smaller batteries under the passenger knees.  Both

were part of my intended design, and let to a slight shift in

aft CG...which you pointed out.  But to go further than that

by much, like if I wanted to switch props, and do some other

funky stuff, won't give the same loading options that I have.

I actually can hold the nose off to REAL slow speeds even

when there are only front-seaters on board., so trim is not

an issue at all, nor is elevator authority.  Personally I

think the goal should be to stay as close to the very far

forward CG position like N410RV has as you CAN....only making

the compromises to put weight aft that you need to for your

other goals.  It's been said over and over that being aft

CG by too far is the most dangerous...and it's far more

important to be in CG than under gross when considering your

loadings. So preserving as much of the forward CG is

a good idea.



Yep, will see you there at BNW!



Tim Olson - RV-10 N104CD - Flying

do not archive

Condrey, Bob (US SSA) wrote:

 	  Quote: 	
		   

 

 Tim,

 

 You bring up a good point about configuration differences.  There is a

 lot of focus on empty weight but equally important is where the empty

 weight CG winds up.  

 

 Regarding Alex's plane - Although John N. built it (but didn't do the

 finish work), the airframe itself is in a stock configuration and

 doesn't have some of the telltale signs of being built by John N. (i.e.

 second set of fuel tanks outboard).  That plane does have AC and a heavy

 looking interior but even with full flaps on approach there's plenty of

 trim authority, he just prefers half flaps.

 

 Regarding comments from Deems, it seems strange that with the small

 continental up front that you'd still have a CG in the forward part of

 the envelope.  I've never flown that plane but do have the numbers from

 410RV and its empty weight ARM is at 106.99".  You'd think with a

 lighter engine that the CG would be a little farther aft

 

 I also notice that your empty weight Arm is 108.67" (from your POH) and

 mine is 108.20" which makes a huge difference in the handling feel.  

 

 See you Saturday at BNW!

 

 Bob

dlm46007(at)cox.net
Guest

Posted: Thu Jun 12, 2008 7:47 am Post subject: Emailing: sb08-6-1[1]

My point with respect to running out of up trim, is: if the trim was not

proper, the left elevator half could be commanding nose down while the right

elevator could be commanding nose up. Could be a real problem at high cruise

speed or even abrupt movement of the controls near maneuvering speed. IIRC

the V tail bonanza used to peel the leading edges of the ruddervators back

in opposite directions until the fifth or so AD fixed it. A mistake on a

factory airplane is hard to believe but not impossible.



--

indigoonlatigo(at)msn.com
Guest

Posted: Thu Jun 12, 2008 8:21 am Post subject: Emailing: sb08-6-1[1]

But also think not only of a twisted HS theory but remember the tail fuse skin is part of this equation, I don't see it so much as compression problem as a shearing problem...the fuse side skin going in a different direction from longeron and the horizontal angle that is going across the top and fastening to the HS stab. As though the HS is not rolling, but rather yawing and cycling with some harmonic.

  

 John G. 409



[quote] From: daveleikam(at)wi.rr.com

 To: rv10-list(at)matronics.com

 Subject: Re: Emailing: sb08-6-1[1]

 Date: Thu, 12 Jun 2008 00:36:05 -0500

 

 --> RV10-List message posted by: "Dave Leikam" <daveleikam(at)wi.rr.com>

 

 After looking closely at the pictures, it appears that the metal is not only 

 cracked, but also "crinkled." If you look at the skin to the left of the 

 crack, it appears to also be deformed which concurs with the failure of the 

 bulkhead. First thought is there was substantial down pressure 

 (compression) on the longeron and on the F1010A angle at this point. 

 Except when rolling, would there ever be uneven force on the HS? And even 

 then I would think the forces would be very little. Would it be possible to 

 detect equal tensional stress on the other side?

 

 I agree with the twisted HS theory.

 

 Dave Leikam

 #40496 N89DA (Reserved)

 Muskego, WI

 

 

 - Original Message ----- 

 From: "David McNeill" <dlm46007(at)cox.net>

 To: <rv10-list(at)matronics.com>

 Sent: Wednesday, June 11, 2008 11:29 PM

 Subject: RE: RV10-List: Emailing: sb08-6-1[1]

 

 

 > --> RV10-List message posted by: "David McNeill" <dlm46007(at)cox.net>

 >

 > I doubt it was the engine. I just talked with someone who flew the 220

 > version for transition training September 2007. He squawked the aircraft 

 > for

 > inadequate up trim. I have flown the 540 version for 33 hours and never

 > gotten the trim setting more than 2 bars from neutral. Inadequate up trim

 > suggest to me that a improperly rigged trim system might have the two

 > elevator halves fighting each other and twisting the elevators and 

 > stressing

 > the horizontal stab.

 >

 > --

rene(at)felker.com
Guest

Posted: Thu Jun 12, 2008 12:23 pm Post subject: Emailing: sb08-6-1[1]

Tim, I fell into the forward CG trap.  I put moving the CG aft as one of my

design objectives based on discussions on the old Yahoo list and this list.

In doing so I did move the CG back a little and now I am regretting it

because it limits the amount of weight I can put in the back of the plane

without running out of the aft CG.  In the end I like what I did from a

design point and may have done it that way anyway.  



I have a bigger battery in the back and I put my O2 system behind the

baggage compartment bulkhead.



I am now thinking of adding a little weight to the engine......got any ideas

on some useful things I could put up there?



Rene' Felker

RV-10 N423CF Flying

801-721-6080



--

AV8ORJWC

Joined: 13 Jul 2006
Posts: 1149
Location: Aurora, Oregon "Home of VANS"

Posted: Thu Jun 12, 2008 2:38 pm Post subject: Emailing: sb08-6-1[1]

Know your aircraft's mission!  It is time for Tim James to provide

discussion and pictures on his roll bar, VGs and low slow speed

improvements.  While he is at it, he can mention the tail

counter-weights which brought his CG "Dead nuts on".



Like Clint said..."A man has to know his limitations".  Following the

plan is great and safe. It should never be discouraged.  Knowing why the

10 is built or designed the way it is, is important as a baseline.  When

you know more or are trying something Experimental there are lots of

options available to those with proper training, technical education and

skill.

I don't think there will ever be a factory discussion on what led to

this crack.  Or why the J stringer make contact or that the doubler is

the final solution or that the bulkhead might have been spec'ed with a

beefier stock of material.  It is just a fix without meaningful

discussion.  Those who are on to asymmetric horizontal trim control may

just have stubbed their toe on a potential cause.  Great discussions.

More fleet hours and less accidents are a good thing.



Tim mentioned several of the variables.  Now why would N220RV have it

and N410RV with significantly more hours be okay?



John Cox



--

Kelly McMullen

Joined: 16 Apr 2008
Posts: 1188
Location: Sun Lakes AZ

Posted: Thu Jun 12, 2008 3:35 pm Post subject: Emailing: sb08-6-1[1]

Is the target empty wt CG what 410RV has or something else? I believe

it has well over 1000 hours on it now, as it was over 900 last August

when I flew in it.

It would seem desirable to start planning towards whatever the goal is

from the start of the tail cone on. Wonder if

Vans will spec that bulkhead in subsequent kits for the next thickness

up. I expect I will have the same as all others when I pickup my

empenage kit, allegedly arriving tomorrow.

Kelly

Builder # yet to come.



On Thu, Jun 12, 2008 at 3:34 PM, John Cox <johnwcox(at)pacificnw.com> wrote:

 	  Quote: 	
		   



 Know your aircraft's mission!  It is time for Tim James to provide

 discussion and pictures on his roll bar, VGs and low slow speed

 improvements.  While he is at it, he can mention the tail

 counter-weights which brought his CG "Dead nuts on".

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor
KCHD

jcumins(at)jcis.net
Guest

Posted: Thu Jun 12, 2008 3:54 pm Post subject: Emailing: sb08-6-1[1]

I talked to Vans yesterday to ask that exact question.  There is no plans to

change the bulkhead to a thicker product.  The doublers are the final fix to

it as of yesterday.



I received my Emp. Kit today and now have a very full garage.  Kelly make

lots of room the box is 11 ft long almost 4 ft wide and weights 300 pounds.



I am serial number 40864 and anything after 40866 will have the sb kit

included in build kit.

So the fun begins. 



John G. Cumins

#40864 Inventory starting soon.



Your Total Technology Solution Provider

--

partner14

Joined: 12 Jan 2008
Posts: 540
Location: Granbury Texas

Posted: Thu Jun 12, 2008 5:23 pm Post subject: Emailing: sb08-6-1[1]

Rene, I added a dry sump oil seperator that looks pretty cool.... might add a couple of pounds.  I wanted to do what I could to keep the crud off the bottom of the plane.  Designed for big block engines, so it should handle the IO540.

  Don McDonald

  #40636  Still Finishing.



Rene Felker <rene(at)felker.com> wrote: 

  [quote]--> RV10-List message posted by: "Rene Felker" 

Tim, I fell into the forward CG trap. I put moving the CG aft as one of my

design objectives based on discussions on the old Yahoo list and this list.

In doing so I did move the CG back a little and now I am regretting it

because it limits the amount of weight I can put in the back of the plane

without running out of the aft CG. In the end I like what I did from a

design point and may have done it  that way anyway. 



I have a bigger battery in the back and I put my O2 system behind the

baggage compartment bulkhead.



I am now thinking of adding a little weight to the engine......got any ideas

on some useful things I could put up there?



Rene' Felker

RV-10 N423CF Flying

801-721-6080



--

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Don A. McDonald
40636

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