Van's Air Force
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Any further information on rudder failure?
- Thread starter RV7AV8R
- Start date
jsharkey
Well Known Member
I have the habit of moving my -6 around by standing in front of the empenage and pushing it backwards using the leading edges of the VS and HS. These are way sturdier on a Van's than anything else I have flown but I'm sure that this practice applies more load than they ever see in flight and have wondered if it could cause damage that might eventually lead to an inflight failure.
How do others maneuver their Van's tail draggers on the ground?
Jim Sharkey
RV-6
How do others maneuver their Van's tail draggers on the ground?
Jim Sharkey
RV-6
chris mitchell
Well Known Member
Yes - I do exactly as you do and I wonder if it is not a good practise??? I am going to build myself something to clip onto the tail wheel for moving the aircraft into/out of the hangar. Not quite sure how it will look yet....
Chris
Chris
Mike, thanks for the link. I was just talking to a Cessna 140 owner on the weekend and lamenting that the same thing wasn't available for the RV's. Maybe we should design a home-grown solution?
Of course, it does mean adding weight to the tail of your RV... And it might stick out in flight if you roll. Not much of an issue for a 140.
Of course, it does mean adding weight to the tail of your RV... And it might stick out in flight if you roll. Not much of an issue for a 140.
flyboy1963
Well Known Member
rudder bar - locking
surely one of the great minds in the homebuilding world could devise a camloc or dzus type fastener, so a twist would lock the tube in a positive way.
Not as sexy, but a pin almost flush with the surface would do it, to!
surely one of the great minds in the homebuilding world could devise a camloc or dzus type fastener, so a twist would lock the tube in a positive way.
Not as sexy, but a pin almost flush with the surface would do it, to!
mculver
Well Known Member
Actually when Bud designed the commercial version, he set the tube up in a way that there is just enough friction to require you to pull it out. I'll have to look at the one on my plane to figure out how it's set up.
But to get back to how this is related to vertical stabs, at least in the case of the Luscombe it's easy to crack the VS attach bracket when you use the stab as a handle to maneuver the plane on the ground. There was an incident a few years ago where the stab partially separated in flight as a result. Oddly, also in Canada. The pilot was able to land safely, though.
I plan to install one of these on the -9 that I am building.
But to get back to how this is related to vertical stabs, at least in the case of the Luscombe it's easy to crack the VS attach bracket when you use the stab as a handle to maneuver the plane on the ground. There was an incident a few years ago where the stab partially separated in flight as a result. Oddly, also in Canada. The pilot was able to land safely, though.
I plan to install one of these on the -9 that I am building.
pierre smith
Well Known Member
They were standard on Cessna Agwagons...
...and Agtrucks. They also had a built-in clip so the handles stayed put.
You'd be surprised at the force applied to a fin during full-rudder crosswind landings. They've been laid over during too high airspeed snap rolls in various airplanes.
Best,
...and Agtrucks. They also had a built-in clip so the handles stayed put.
You'd be surprised at the force applied to a fin during full-rudder crosswind landings. They've been laid over during too high airspeed snap rolls in various airplanes.
Best,
N941WR
Legacy Member
While that looks great, be careful putting that extra weight way back in the tail.
As mentioned in other threads, don't try to fix something that isn't broken. We don't know why that tail came off. It is possible that the builder simply forgot all the bolts or the plane sustained some damage prior to the accident and was not repaired properly. I would try to gather more information before I came up with a ?fix?.
We have one of those BAS handle sets on our C-180, they work great. I would like to have one on my 8, but maybe a winter project
They won't slide out, like Pierre said they clip in. The plane also flies just fine with them sticking out, just ask how many times I have tried
They won't slide out, like Pierre said they clip in. The plane also flies just fine with them sticking out, just ask how many times I have tried
It would only be added cost, more work, and weight in the tail. It is a solution to a problem that does not exist on the RV.
For more than 12.5 years and 2,358 flying hours, I have been moving my RV-6 around with the tail that is already on the airplane. Yes I pick the tailwheel off the ground using the horizontal stab. No ill effect.
mv031161
Well Known Member
tail Wheel Tow bar
Sorry about moving from the original intended article...but since you are all concern about the loads placed during groung handling, i thought you may want to check an article that appeared on Sports Aviation a few months ago, on how to convert a regular under the armpit crutch into a tail wheel tow bar....
Sorry about moving from the original intended article...but since you are all concern about the loads placed during groung handling, i thought you may want to check an article that appeared on Sports Aviation a few months ago, on how to convert a regular under the armpit crutch into a tail wheel tow bar....
RV7AV8R
Well Known Member
My RV7 is so old it has the RV8 Rudder. Were there any recent (2-3 yrs ago)changes to the VS?
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I promise you this........if the tail surfaces on any RV model are installed correctly, pushing the airplane around on the ground using the vertical and horizontal stabilizers will never cause the sufaces to come off in flight. I don't have any idea what may have happened in that crash and it is very strange to read that the vertical stabilizer was found one half mile from the rest of the plane, but if properly installed, the tail did not come off from ground handling. So very sad.
jsharkey
Well Known Member
chepburn
Well Known Member
I have just posted a question to the TSB
Hi all,
I have just sent a question to the Canadian transportation safety board to see if they have any releasable information wrt the accident.
There are various rumours as to the cause of the accident in our RV community in Ottawa, but, since they are rumours, I wont repeat them here.
I will post the TSB response here if they send me one.
Chris
Hi all,
I have just sent a question to the Canadian transportation safety board to see if they have any releasable information wrt the accident.
There are various rumours as to the cause of the accident in our RV community in Ottawa, but, since they are rumours, I wont repeat them here.
I will post the TSB response here if they send me one.
Chris
n5lp
fugio ergo sum
Very unofficial information
I think this is a very unusual case where it would be best to relate some very unofficial and general third hand information. The story I got does not call into question the design or construction of the particular airplane involved nor the piloting skills of the pilot. It really sounds like a case of very bad luck.
Since this is not anything official, if someone deems it appropriate to delete this message, that is fine with me.
I think this is a very unusual case where it would be best to relate some very unofficial and general third hand information. The story I got does not call into question the design or construction of the particular airplane involved nor the piloting skills of the pilot. It really sounds like a case of very bad luck.
Since this is not anything official, if someone deems it appropriate to delete this message, that is fine with me.
RV7AV8R
Well Known Member
This would be a relief to know if it was very bad luck. Such a thing that we can not prepare for in advance, like being hit by a meteor or a goose or swan, would be understandable and part of the acceptable risk we all take. Kind of like hitting a deer on the highway.
There was a VS failure in a Rocket a number of years ago which was traced to the angle doubler attaching the stab deck to the fuse/ fin post rear bulkhead never being installed apparently. The TSB might want to confirm this part was installed.
When I heard about this earlier accident, I looked at my RV10 and there is nothing specified in the plans at this location so I added a piece of angle here. There was nothing tying the 2 parts together on the -10 like on other RVs. Of course the -10 is not aerobatic but it does have a very tall fin. It just looks right having the angle piece installed from a structural point of view.
As a word of caution, snap rolls put huge a loading on the fin. Not sure how many people might do these in RVs but...
When I heard about this earlier accident, I looked at my RV10 and there is nothing specified in the plans at this location so I added a piece of angle here. There was nothing tying the 2 parts together on the -10 like on other RVs. Of course the -10 is not aerobatic but it does have a very tall fin. It just looks right having the angle piece installed from a structural point of view.
As a word of caution, snap rolls put huge a loading on the fin. Not sure how many people might do these in RVs but...
sprucemoose
Well Known Member
I remember the Rocket accident that you're talking about. Ever since then I make it a practice to always look for this part on projects that I TC.
That said... geez, do you really want to be modifying a primary structure like this? Did you perform any engineering on this mod or just TLAR it?
TLAR "engineering". Proactive in my view. The factory brought out a VS hinge point doubler mod and a stab mount bulkhead doubler mod after cracks were found in their prototype. The RV10 airframe is very light given the size of aircraft and kudos for Van's in keeping it light but I just didn't like the fact that the longerons are not tied to the fin post bulkhead like in other RVs. No doubt in my mind it is stronger with the angle piece installed.
Figured I'd catch some flak posting it and not saying anyone else should follow what I've done and also not saying there is a problem with the original design. Just information.
Figured I'd catch some flak posting it and not saying anyone else should follow what I've done and also not saying there is a problem with the original design. Just information.
can you post pictures of this piece you speak of?
chepburn
Well Known Member
The response from the TSB
Well,
I received the answer that I sort of expected. Patience will be required I suppose. At least they answered... hopefully, the wait will not be too long.
Quote:
Dear Mr. Hepburn,
We have received your e-mail asking when the Transportation Safety Board
of Canada (TSB) report A10O0018 will be released.
This occurrence is still under investigation and unfortunately, the TSB
cannot estimate the publication date of the report. The TSB aims to
publish investigation reports as quickly as possible, however, the
agency takes the time necessary to do a quality investigation and to
produce a report that will advance safety and meet the expectations of
the Canadian public and the transportation industry.
Below is the link to the subscription services page for the TSB. The
subscription page lets you choose documents for which you would like to
receive a notification. When the document is posted on our Web site, an
e-mail that includes a short summary and a link to the document on our
Web site will be sent to you.
Please use the following link to subscribe to our electronic
subscription service: http://listserv.tsb.gc.ca/en/subscribe/.
Well,
I received the answer that I sort of expected. Patience will be required I suppose. At least they answered... hopefully, the wait will not be too long.
Quote:
Dear Mr. Hepburn,
We have received your e-mail asking when the Transportation Safety Board
of Canada (TSB) report A10O0018 will be released.
This occurrence is still under investigation and unfortunately, the TSB
cannot estimate the publication date of the report. The TSB aims to
publish investigation reports as quickly as possible, however, the
agency takes the time necessary to do a quality investigation and to
produce a report that will advance safety and meet the expectations of
the Canadian public and the transportation industry.
Below is the link to the subscription services page for the TSB. The
subscription page lets you choose documents for which you would like to
receive a notification. When the document is posted on our Web site, an
e-mail that includes a short summary and a link to the document on our
Web site will be sent to you.
Please use the following link to subscribe to our electronic
subscription service: http://listserv.tsb.gc.ca/en/subscribe/.
Rudder Failure
I just pick up the RV-3 with the tailwheel spring and move it around, I have a taildragger dragger but Most of the time I just pick up the tail and move it. Every flight instructer I ever had always advised against using the vertical or horizontal stabs. I suppose there are many opinions.
Ed Hawkins
N272DR
I just pick up the RV-3 with the tailwheel spring and move it around, I have a taildragger dragger but Most of the time I just pick up the tail and move it. Every flight instructer I ever had always advised against using the vertical or horizontal stabs. I suppose there are many opinions.
Ed Hawkins
N272DR
RV7AV8R
Well Known Member
Thanks Chris, Please continue to keep us informed. This is such a mystery to me. In general, it is hard to even speculate on possible reasons why a rudder would fall off an RV beyond flutter.
Correct me if I'm wrong - but from a physics perspective it occurs to me that on each and every takeoff, the HS is generating sufficient downward force to lift the nosewheel, and that force is generated from air loads on the HS and elevators. The structure doesn't know the difference between air loads and human-hand loads. If that loading was a "bad thing" we would be cycle-limiting the tail life.
Jamie
Well Known Member
...and on one side.
Having been involved in an investigation and obtaining facts on another a couple years back, the TSB usually takes 6-24 months to conclude an investigation and they may or may not publish the findings on the web. The Canadian mandate is not the same as that of the NTSB in the US.
I do hope they find the cause of this mysterious accident.
rv7boy
Forum Peruser
Ground handling via the horizontal stabilizer
OK, Greg, here's my effort at "correction:" I've seen folks (me included) move 172's by sitting on the horizontal stab to lift the nosewheel. I have just recently learned that this concentrated load can damage the front spar on 172 HS's. Cessna has issued a Service Bulletin for inspection and repair of front spars on the 172 horizontal stabilizer. Compared to many 172 maintenance items it can be expensive if repair is required.
Here's a quote from a Flight Training article at the AOPA.org web site:"There aren't too many maintenance gotchas on a fixed-gear 172. Look for buckles and deformation in the horizontal stabilizer front spar. The spar is sufficiently strong for normal flight loads, but until pilots stop sitting on the horizontal stabilizer, using body weight to lift the nose gear so they can horse the airplane around on the ground, these spars will continue to be damaged. Cessna Service Bulletin SEB94-8 addresses the inspection and repair."
I would hope the RV horizontal stabilizer is stronger than the venerable 172 horizontal stabilizer. I plan to avoid moving my RV with the tail surfaces.
OK, Greg, here's my effort at "correction:" I've seen folks (me included) move 172's by sitting on the horizontal stab to lift the nosewheel. I have just recently learned that this concentrated load can damage the front spar on 172 HS's. Cessna has issued a Service Bulletin for inspection and repair of front spars on the 172 horizontal stabilizer. Compared to many 172 maintenance items it can be expensive if repair is required.
Here's a quote from a Flight Training article at the AOPA.org web site:"There aren't too many maintenance gotchas on a fixed-gear 172. Look for buckles and deformation in the horizontal stabilizer front spar. The spar is sufficiently strong for normal flight loads, but until pilots stop sitting on the horizontal stabilizer, using body weight to lift the nose gear so they can horse the airplane around on the ground, these spars will continue to be damaged. Cessna Service Bulletin SEB94-8 addresses the inspection and repair."
I would hope the RV horizontal stabilizer is stronger than the venerable 172 horizontal stabilizer. I plan to avoid moving my RV with the tail surfaces.
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scsmith
Well Known Member
Not quite!
The center of lift of the wing is in front of the main landing gear contact point on a tricycle gear airplane. At some speed, the combination of wing lift and tail download is sufficient to lift the nose wheel. But the load on the tail is far less than what would be required to lift the nose wheel with no wing lift.
I would not recommend lifting the nose wheel on an RV by pushing on the H-stab. Done carefully, it is probably OK, but the structure is pretty light - I would avoid it. Also should not lift the tail wheel on a 'conventional gear' RV by lifting on the H-tail.
The center of lift of the wing is in front of the main landing gear contact point on a tricycle gear airplane. At some speed, the combination of wing lift and tail download is sufficient to lift the nose wheel. But the load on the tail is far less than what would be required to lift the nose wheel with no wing lift.
I would not recommend lifting the nose wheel on an RV by pushing on the H-stab. Done carefully, it is probably OK, but the structure is pretty light - I would avoid it. Also should not lift the tail wheel on a 'conventional gear' RV by lifting on the H-tail.
Bill Wightman
Well Known Member
On the RV7/8, the highest horizontal tail loads would be seen during maneuvering flight, not takeoff/landing.
The worst case scenario would be a forward CG, max aerobatic GW, maneuvering speed pull to max allowable G. Under these conditions, the tail would need to produce about 500# of down force.
Of course, the tail "lift" is distributed across its span, but the attachment points to the fuselage still must be able to react a force of this magnitude, plus factor of safety no matter if the load is concentrated or not.
I've not analyzed the 7 or 8 for yawing forces, but the V-stab also can be subjected to huge loads as mentioned before.
The worst case scenario would be a forward CG, max aerobatic GW, maneuvering speed pull to max allowable G. Under these conditions, the tail would need to produce about 500# of down force.
Of course, the tail "lift" is distributed across its span, but the attachment points to the fuselage still must be able to react a force of this magnitude, plus factor of safety no matter if the load is concentrated or not.
I've not analyzed the 7 or 8 for yawing forces, but the V-stab also can be subjected to huge loads as mentioned before.
scsmith
Well Known Member
Bad to lift or push down on tail
My main concern is that the H-tail only has 3 ribs. If you push down near the leading edge, you are putting considerable load in through the very few ribs. Flight loads have a more distributed load path into the two spars, and yes, can take many hundreds of pounds of lift that way. I'm not at all concerned about the attach point loads.
My main concern is that the H-tail only has 3 ribs. If you push down near the leading edge, you are putting considerable load in through the very few ribs. Flight loads have a more distributed load path into the two spars, and yes, can take many hundreds of pounds of lift that way. I'm not at all concerned about the attach point loads.
Barry_Barry
Member
More or Less pressure
Jim & Gaggle:
Just my thoughts on this:
The question being: Does pushing the plane around by the tail feathers cause forces equal to the G rating, or greater of the plane ?
I would have to say NO considering 'Normal' pushing... Normal pushing, well that has to be defined; I would say smooth ground or turf. When you talk about mud or snow or up hills, normal becomes a variable.
I put the forces required much less than normal flying forces. Consider this: A plane in straight & level flight has a downward force on the tail equal to the counter balance weight required to keep the nose up. Work out your W&B as the CG being your pivot point and consider that the downward force has to be equal to that nose weight JUST to keep your nose level. No go into a climb... Until the climb is stabilized the forces are greater than the nose weight. Now let's take it to the next level - - - What happens when you do a maneuver such as a loop. Yes, the forces increase even more. In design the plane is stress to cover what the G rating of the plane is. So if there is 100 Lbs of flying force on the tail just to keep it S&L and you do a 3 G maneuver (pull out) you now have 300 Lbs on the tail. You pushing around of the tail is no where near 300 Lbs of force.
Another way to consider this force is: What is your Tail Weight? You know, the weight of your tail when placed on a scale. Well, in flight you have a lifting force equal to that force just to keep the plane S&L. Would you say your tail is 100 Lbs? And that is without any pilot or passage or baggage.
So, does moving your plane around by the tail feathers damage anything? NO - Not under normal conditions. Just don't shoulder block your vertical stab to get it to move.
Barry
Jim & Gaggle:
Just my thoughts on this:
The question being: Does pushing the plane around by the tail feathers cause forces equal to the G rating, or greater of the plane ?
I would have to say NO considering 'Normal' pushing... Normal pushing, well that has to be defined; I would say smooth ground or turf. When you talk about mud or snow or up hills, normal becomes a variable.
I put the forces required much less than normal flying forces. Consider this: A plane in straight & level flight has a downward force on the tail equal to the counter balance weight required to keep the nose up. Work out your W&B as the CG being your pivot point and consider that the downward force has to be equal to that nose weight JUST to keep your nose level. No go into a climb... Until the climb is stabilized the forces are greater than the nose weight. Now let's take it to the next level - - - What happens when you do a maneuver such as a loop. Yes, the forces increase even more. In design the plane is stress to cover what the G rating of the plane is. So if there is 100 Lbs of flying force on the tail just to keep it S&L and you do a 3 G maneuver (pull out) you now have 300 Lbs on the tail. You pushing around of the tail is no where near 300 Lbs of force.
Another way to consider this force is: What is your Tail Weight? You know, the weight of your tail when placed on a scale. Well, in flight you have a lifting force equal to that force just to keep the plane S&L. Would you say your tail is 100 Lbs? And that is without any pilot or passage or baggage.
So, does moving your plane around by the tail feathers damage anything? NO - Not under normal conditions. Just don't shoulder block your vertical stab to get it to move.
Barry
Tom Martin
Well Known Member
Although I push on my tail to move my airplane on the ramp if I have to move it through tough conditions I steer with the tail and get others to push on the wing. As for the 300 lb push, I must debate that number. When I am at the gym on a regular basis I can easily do leg bench presses of over 500 lbs. The action is not unlike bending forward and pushing hard with your legs and with hips against the HS stab. I am not a large man, 5'8", 175lbs, nor am I a super strong guy. Watch some young fellows at the gym and you will see how much energy your legs can create.
RV7AV8R
Well Known Member
Maneuvering on the ground
My simple low cost tool for maneuvering my tail dragger is a 5 ft rope and wood handle (like on a small engine starter rope). I loop the rope on the tail wheel spring and pull it around with ease. Wrap the rope up and it takes less space in the plane than a can of Coke.
My simple low cost tool for maneuvering my tail dragger is a 5 ft rope and wood handle (like on a small engine starter rope). I loop the rope on the tail wheel spring and pull it around with ease. Wrap the rope up and it takes less space in the plane than a can of Coke.
Rope
This is a really clever idea! Pull on the rope to move left/right/back, pull on the prop to move forward.
jimski9
Member
Rudder failure
To answer the original thread question, the Transportation Safety Board of Canada accident report on Vans RV-7A C-GNDY is available.
The web link is a bit long to post.
Google search "C-GNDY" and it should appear as [PDF] AVIATION INVESTIGATION REPORT A10O0018 IN-FLIGHT ...
[ed. Link HERE. dr]
To answer the original thread question, the Transportation Safety Board of Canada accident report on Vans RV-7A C-GNDY is available.
The web link is a bit long to post.
Google search "C-GNDY" and it should appear as [PDF] AVIATION INVESTIGATION REPORT A10O0018 IN-FLIGHT ...
[ed. Link HERE. dr]
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panhandler1956
Well Known Member
That's what I use. We have horses so I just use a lead rope to pull my little 'stang around. I still push on the horizontal sometimes, but I'm conscious when I do.
David Paule
Well Known Member
Note that pushing on the tail generally means applying an aft or side force. The forces the tail is designed for usually are perpendicular to that.
Dave
Dave
Amazing accident report
http://www.bst-tsb.gc.ca/eng/rapports-reports/aviation/2010/a10o0018/a10o0018.pdf
I have never read such a through accident report. The US NTSB does not produce anything close to this report.
Thank you for sharing.
http://www.bst-tsb.gc.ca/eng/rapports-reports/aviation/2010/a10o0018/a10o0018.pdf
I have never read such a through accident report. The US NTSB does not produce anything close to this report.
Thank you for sharing.
BillL
Well Known Member
The NTSB file for the Georgia crash had all the collected flight data as attachments. That was very helpful for this (VAF) group to inspect/analyze and discuss to reach a conclusion. The Canadian data is mentioned, and indeed analyzed, but it was not attached. I looked to see if they had it on the canadian site, but could not find it. So, although the Canadian report is better (ok, much better), their availability of attached data is (apparently) not.
update: The data is available upon request, Thanks Snowflake
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