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N81JG(at)aol.com
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 Posted: Wed Mar 23, 2011 7:56 pm Post subject: RV6 fuel tank sealant |
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New subject---
Does anyone have experience with the sloshing agent used to seal the fuel tanks prior to about 1994? I have heard of the agent sloughing off and blocking fuel pickup. Is this a sudden occurrence without any warning? Should all the sloshed tanks be replaced with Prosealed tanks? This is not a problem with my RV7A, but the tanks in a friend's RV6A.
John Greaves
RV7A N781JG
Redding, CA
In a message dated 3/23/2011 2:44:43 P.M. Pacific Daylight Time, andrew.d.zachar(at)gmail.com writes:
| Quote: | Flight Test Engineer. Worked in Kansas and North Carolina.
But, I'm a young guy and don't have as much experience as a lot of guys who are probably reading this list, so full disclosure, most of my knowledge comes from various advisory circulars and flight test guides.
Being a CFI has reinforced that I need to be conservative and being in Flight Test has reinforced that I need to seek other's experiences before embarking on stuff on my own. Modern flight test is a little like being a litigation attorney. We don't ever ask a question in the courtroom (fly a test) for which we don't already know the answer (have previous experience, data, or windtunnel predictions.) Surprises during any type of flight test are a bad, bad thing.
I think with aft-CG testing of RVs, going slow is good advice, but I'm actually most interested in hearing the data from others' expansions. Did they expand slow or fast, what results did they see?
Your shared experience is a good one to keep in mind.
-az
On Wed, Mar 23, 2011 at 2:09 PM, Louis Willig <larywil(at)comcast.net (larywil(at)comcast.net)> wrote:
| Quote: | --> RV-List message posted by: Louis Willig <larywil(at)comcast.net (larywil(at)comcast.net)>
Andrew, this is an excellent post. Wish you gave us your "day job" description. It sounds interesting.
I wasn't going to post on this question, since many members on this list have so much more experience than I have. However, as a 12 year RV-4 veteran, I just want to re-enforce your CG guidelines. Most of us quickly feel the effects of extra gross weight each time we take off after refueling, or take off or land with a passenger. What we don't "feel" as quickly or as often is the effects of pushing close to the CG limits. We are constantly making small adjustments in trim while always remaining within the envelope. It would be a shock to most of us if we made these adjustments to a plane that was loaded near the edge to start with.
I had an "aft CG" experience many years ago with a passenger who weighed 240#. I don't know how he even fit in the back seat, but he did. And I didn't realize what I was doing ( yes, I was stupid). When landing, I failed to add extra speed, and the aircraft stalled sharply, dropped a wing, and raised my blood pressure. All this, in the blink of an eye, with no telltale to a novice like me. I was only 6 inches off the ground but you would have thought I was two feet high. No damage, but very embarrassing. This problem is probably more acute in the -4's and -8's. So we pay more attention to CG.
Look, I am not experience or capable enough to advise anyone how to fly their RV. I just thought I would step in to say that an aft CG lightens the stick feel under some circumstances (when you are already slow and trimmed forward) and can help you learn the "Flying Farmer" routine very quickly. 
Louis
At 11:54 AM 3/23/2011, you wrote:
| Quote: | I'm far from getting into phase 1 with my RV-7, but I have a little insight from my day job.
We approach weight and CG changes with great care and in many small steps. Generally, someone like Van's will put weight and CG limits on the airplane because outside of those limits, some limit may be exceeded (this could be a handling requirement if it's a certified airplane, etc.).
| Quote: | From some guidance material, the effects of higher weights on the aircraft:
|
菱igher takeoff speed.
畢onger takeoff run.
紐educed rate and angle of climb.
畢ower maximum altitude.
百horter range (more weight lifted = more work done = more fuel required).
紐educed cruising speed.
紐educed maneuverability.
菱igher stalling speed.
菱igher landing speed.
畢onger landing roll.
髭xcessive weight on the nosewheel.
The effects of adverse CG conditions can be:
FWD CG causes problems in controlling and raising the nose
AFT CG affects longitudinal stability, and can reduce the airplane痴 capability to recover from stalls and spins (decreased rudder and elevator moments due to shorter arm (distance) from CG to control surfaces).
AFT CG also yields very light control forces. (This makes it easy for the pilot to inadvertently overstress the airplane.)
FWD CG is also limited by elevator effectiveness at slow speeds.
Anyway, the point is that by expanding the envelopes during testing, you can watch for these effects. If you do it slowly, you can watch for trends, instead of just going to the endpoint all in one go and getting yourself into a situation where something (like light longitudinal control forces) can get you into trouble if you aren't expecting it.
Hope this helps.
-az
On Wed, Mar 23, 2011 at 10:16 AM, Ralph E. Capen <<mailto:recapen(at)earthlink.net (recapen(at)earthlink.net)>recapen(at)earthlink.net (recapen(at)earthlink.net)> wrote:
--> RV-List message posted by: "Ralph E. Capen" <<mailto:recapen(at)earthlink.net (recapen(at)earthlink.net)>recapen(at)earthlink.net (recapen(at)earthlink.net)>
I did mine in stages.
It was pretty weird strapping in a bag of sand......
-----Original Message-----
>From: thomas sargent <<mailto:sarg314(at)gmail.com (sarg314(at)gmail.com)>sarg314(at)gmail.com (sarg314(at)gmail.com)>
| Quote: | Sent: Mar 22, 2011 4:06 PM
|
>To: rv-list <<mailto:rv-list(at)matronics.com (rv-list(at)matronics.com)>rv-list(at)matronics.com (rv-list(at)matronics.com)>
| Quote: | Subject: RV-List: max gross weight test
I am just about done testing my 6A. I specified a max gross at 1720lbs and
will fly it at that weight in a couple days. (Empty weight was 1076.) I
know some planes have significantly higher max gross weights. So far in my
tests (all solo), weight doesn't seem to change behavior very much.
Fully loaded the CG will be at 74.6" (in the 68.7 - 76.8 range), so it's
still more than 2" forward of the aft limit, although I haven't flown it
that far aft before. I think I've had it no further aft than about 72" or
72.5".
Should I approach the max gross configuration in a few steps or is it
reasonable to just go for it in one flight?
--
Tom Sargent
|
========================
get="_blank">http://www.matronics.com/Navigator?RV-List
===========
http://forums.matronics.com
===========
le, List Admin.
="_blank">http://www.matronics.com/contribution
===========
--
Andrew Zachar
<mailto:andrew.d.zachar(at)gmail.com (andrew.d.zachar(at)gmail.com)>andrew.d.zachar(at)gmail.com (andrew.d.zachar(at)gmail.com)
|
===========
target="_blank">http://www.matronics.com/Navigator?RV-List
===========
MS -
k">http://forums.matronics.com
===========
e -
-Matt Dralle, List Admin.
t="_blank">http://www.matronics.com/contribution
===========
|
--
Andrew Zachar
andrew.d.zachar(at)gmail.com (andrew.d.zachar(at)gmail.com)
|
[quote][b]
| | - The Matronics RV-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RV-List |
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Ed Anderson
Joined: 10 Jan 2006
Posts: 475
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| Posted: Thu Mar 24, 2011 2:25 am Post subject: RV6 fuel tank sealant |
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|
John, I have been flying with the sloshed tanks in an RV-6A since 1998 using both Mogas and 100LL with no problem (so far). My understanding is that if the tanks surfaces were properly prepared and the slosh properly apply there is no problem. However, with less "perfect" application, the slosh can and has broken away from the tank surfaces and blocked filters. This apparently can happen suddenly, although a number of folks have reported finding white flakes in their fuel filters before it got to that point.
There used to be some folks who would take your tanks and clean out the slosh - but the cost was not cheap and I think they finally decided better in the long run just to build new tanks with proseal only.
Ed
Edward L. Anderson
Anderson Electronic Enterprises LLC
305 Reefton Road
Weddington, NC 28104
http://www.andersonee.com
http://www.eicommander.com
From: N81JG(at)aol.com (N81JG(at)aol.com)
Sent: Wednesday, March 23, 2011 11:53 PM
To: rv-list(at)matronics.com (rv-list(at)matronics.com)
Subject: RV6 fuel tank sealant
New subject---
Does anyone have experience with the sloshing agent used to seal the fuel tanks prior to about 1994? I have heard of the agent sloughing off and blocking fuel pickup. Is this a sudden occurrence without any warning? Should all the sloshed tanks be replaced with Prosealed tanks? This is not a problem with my RV7A, but the tanks in a friend's RV6A.
John Greaves
RV7A N781JG
Redding, CA
In a message dated 3/23/2011 2:44:43 P.M. Pacific Daylight Time, andrew.d.zachar(at)gmail.com writes:
| Quote: | Flight Test Engineer. Worked in Kansas and North Carolina.
But, I'm a young guy and don't have as much experience as a lot of guys who are probably reading this list, so full disclosure, most of my knowledge comes from various advisory circulars and flight test guides.
Being a CFI has reinforced that I need to be conservative and being in Flight Test has reinforced that I need to seek other's experiences before embarking on stuff on my own. Modern flight test is a little like being a litigation attorney. We don't ever ask a question in the courtroom (fly a test) for which we don't already know the answer (have previous experience, data, or windtunnel predictions.) Surprises during any type of flight test are a bad, bad thing.
I think with aft-CG testing of RVs, going slow is good advice, but I'm actually most interested in hearing the data from others' expansions. Did they expand slow or fast, what results did they see?
Your shared experience is a good one to keep in mind.
-az
On Wed, Mar 23, 2011 at 2:09 PM, Louis Willig <larywil(at)comcast.net (larywil(at)comcast.net)> wrote:
| Quote: | --> RV-List message posted by: Louis Willig <larywil(at)comcast.net (larywil(at)comcast.net)>
Andrew, this is an excellent post. Wish you gave us your "day job" description. It sounds interesting.
I wasn't going to post on this question, since many members on this list have so much more experience than I have. However, as a 12 year RV-4 veteran, I just want to re-enforce your CG guidelines. Most of us quickly feel the effects of extra gross weight each time we take off after refueling, or take off or land with a passenger. What we don't "feel" as quickly or as often is the effects of pushing close to the CG limits. We are constantly making small adjustments in trim while always remaining within the envelope. It would be a shock to most of us if we made these adjustments to a plane that was loaded near the edge to start with.
I had an "aft CG" experience many years ago with a passenger who weighed 240#. I don't know how he even fit in the back seat, but he did. And I didn't realize what I was doing ( yes, I was stupid). When landing, I failed to add extra speed, and the aircraft stalled sharply, dropped a wing, and raised my blood pressure. All this, in the blink of an eye, with no telltale to a novice like me. I was only 6 inches off the ground but you would have thought I was two feet high. No damage, but very embarrassing. This problem is probably more acute in the -4's and -8's. So we pay more attention to CG.
Look, I am not experience or capable enough to advise anyone how to fly their RV. I just thought I would step in to say that an aft CG lightens the stick feel under some circumstances (when you are already slow and trimmed forward) and can help you learn the "Flying Farmer" routine very quickly.
Louis
At 11:54 AM 3/23/2011, you wrote:
| Quote: | I'm far from getting into phase 1 with my RV-7, but I have a little insight from my day job.
We approach weight and CG changes with great care and in many small steps. Generally, someone like Van's will put weight and CG limits on the airplane because outside of those limits, some limit may be exceeded (this could be a handling requirement if it's a certified airplane, etc.).
| Quote: | From some guidance material, the effects of higher weights on the aircraft:
|
菱igher takeoff speed.
畢onger takeoff run.
紐educed rate and angle of climb.
畢ower maximum altitude.
百horter range (more weight lifted = more work done = more fuel required).
紐educed cruising speed.
紐educed maneuverability.
菱igher stalling speed.
菱igher landing speed.
畢onger landing roll.
髭xcessive weight on the nosewheel.
The effects of adverse CG conditions can be:
FWD CG causes problems in controlling and raising the nose
AFT CG affects longitudinal stability, and can reduce the airplane痴 capability to recover from stalls and spins (decreased rudder and elevator moments due to shorter arm (distance) from CG to control surfaces).
AFT CG also yields very light control forces. (This makes it easy for the pilot to inadvertently overstress the airplane.)
FWD CG is also limited by elevator effectiveness at slow speeds.
Anyway, the point is that by expanding the envelopes during testing, you can watch for these effects. If you do it slowly, you can watch for trends, instead of just going to the endpoint all in one go and getting yourself into a situation where something (like light longitudinal control forces) can get you into trouble if you aren't expecting it.
Hope this helps.
-az
On Wed, Mar 23, 2011 at 10:16 AM, Ralph E. Capen <<mailto:recapen(at)earthlink.net (recapen(at)earthlink.net)>recapen(at)earthlink.net (recapen(at)earthlink.net)> wrote:
--> RV-List message posted by: "Ralph E. Capen" <<mailto:recapen(at)earthlink.net (recapen(at)earthlink.net)>recapen(at)earthlink.net (recapen(at)earthlink.net)>
I did mine in stages.
It was pretty weird strapping in a bag of sand......
-----Original Message-----
>From: thomas sargent <<mailto:sarg314(at)gmail.com (sarg314(at)gmail.com)>sarg314(at)gmail.com (sarg314(at)gmail.com)>
| Quote: | Sent: Mar 22, 2011 4:06 PM
|
>To: rv-list <<mailto:rv-list(at)matronics.com (rv-list(at)matronics.com)>rv-list(at)matronics.com (rv-list(at)matronics.com)>
| Quote: | Subject: max gross weight test
I am just about done testing my 6A. I specified a max gross at 1720lbs and
will fly it at that weight in a couple days. (Empty weight was 1076.) I
know some planes have significantly higher max gross weights. So far in my
tests (all solo), weight doesn't seem to change behavior very much.
Fully loaded the CG will be at 74.6" (in the 68.7 - 76.8 range), so it's
still more than 2" forward of the aft limit, although I haven't flown it
that far aft before. I think I've had it no further aft than about 72" or
72.5".
Should I approach the max gross configuration in a few steps or is it
reasonable to just go for it in one flight?
--
Tom Sargent
|
========================
get="_blank">http://www.matronics.com/Navigator?RV-List
===========
http://forums.matronics.com
===========
le, List Admin.
="_blank">http://www.matronics.com/contribution
===========
--
Andrew Zachar
<mailto:andrew.d.zachar(at)gmail.com (andrew.d.zachar(at)gmail.com)>andrew.d.zachar(at)gmail.com (andrew.d.zachar(at)gmail.com)
|
===========
target="_blank">http://www.matronics.com/Navigator?RV-List
===========
MS -
k">http://forums.matronics.com
===========
e -
-Matt Dralle, List Admin.
t="_blank">http://www.matronics.com/contribution
===========
|
--
Andrew Zachar
andrew.d.zachar(at)gmail.com (andrew.d.zachar(at)gmail.com)
|
[quote]
href="http://www.matronics.com/Navigator?RV-List">http://www.matronics.com/Navigator?RV-List
href="http://forums.matronics.com">http://forums.matronics.com
href="http://www.matronics.com/contribution">http://www.matronics.com/c
[b]
| | - The Matronics RV-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RV-List |
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_________________
Ed Anderson
Rv-6A N494BW Rotary Powered
Matthews, NC
eanderson@carolina.rr.com |
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Gary.A.Sobek
Joined: 09 Jan 2006
Posts: 217
Location: SoCAL USA
|
| Posted: Thu Mar 24, 2011 6:26 am Post subject: RV6 fuel tank sealant |
|
|
I followed the recommendations of Van's Aircraft that were in effect at the time of construction. I used the WHITE slosh painted over the Pro-Seal and sloshed the rear baffle per the directions at the time.
After 13.5 years of flying and 2,480 flying hours, there has been NO issues. NONE has come off, flaked, or got into my gascolator.
I know of one RV-4 that had a leak in the tank. A yellow slosh was added over the white slosh. The yellow slosh acted adversely on the white slosh and crinkled everything up requiring that the tank be taken apart, cleaned, and resealed.
The White Slosh is alcohol resistant and the Yellow Slosh is not. They are NOT compatible with each other.
Gary A. Sobek
"My Sanity" RV-6 N157GS O-320 Hartzell,
2,484+ Flying Hours So. CA, USA
From: N81JG(at)aol.com
Date: Wed, 23 Mar 2011 23:53:36 -0400
Subject: RV6 fuel tank sealant
To: rv-list(at)matronics.com
New subject---
Does anyone have experience with the sloshing agent used to seal the fuel tanks prior to about 1994? I have heard of the agent sloughing off and blocking fuel pickup. Is this a sudden occurrence without any warning? Should all the sloshed tanks be replaced with Prosealed tanks? This is not a problem with my RV7A, but the tanks in a friend's RV6A.
John Greaves
RV7A N781JG
Redding, CA
[quote][b]
| | - The Matronics RV-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RV-List |
|
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| Back to top |
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Gary.A.Sobek
Joined: 09 Jan 2006
Posts: 217
Location: SoCAL USA
|
| Posted: Thu Mar 24, 2011 6:26 am Post subject: RV6 fuel tank sealant |
|
|
I followed the recommendations of Van's Aircraft that were in effect at the time of construction. I used the WHITE slosh painted over the Pro-Seal and sloshed the rear baffle per the directions at the time.
After 13.5 years of flying and 2,480 flying hours, there has been NO issues. NONE has come off, flaked, or got into my gascolator.
I know of one RV-4 that had a leak in the tank. A yellow slosh was added over the white slosh. The yellow slosh acted adversely on the white slosh and crinkled everything up requiring that the tank be taken apart, cleaned, and resealed.
The White Slosh is alcohol resistant and the Yellow Slosh is not. They are NOT compatible with each other.
Gary A. Sobek
"My Sanity" RV-6 N157GS O-320 Hartzell,
2,484+ Flying Hours So. CA, USA
From: N81JG(at)aol.com
Date: Wed, 23 Mar 2011 23:53:36 -0400
Subject: RV6 fuel tank sealant
To: rv-list(at)matronics.com
New subject---
Does anyone have experience with the sloshing agent used to seal the fuel tanks prior to about 1994? I have heard of the agent sloughing off and blocking fuel pickup. Is this a sudden occurrence without any warning? Should all the sloshed tanks be replaced with Prosealed tanks? This is not a problem with my RV7A, but the tanks in a friend's RV6A.
John Greaves
RV7A N781JG
Redding, CA
[quote][b]
| | - The Matronics RV-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RV-List |
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