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New SB and SL Issued for Pre-'05 Tri-gear models

Nose Gear Group Buy

Hey Captain John, I smell a "Group Buy" opportunity here.
 
Considerations regarding implications of this SB-discussion please!

Many factors to consider:
>Stabilizing aircraft while awaiting gear parts with NG removed
>Nose wheel pant-will it need modification?
>Removing those pesky bolts!
>Will tow bars still fit?
>Will Van's have enough parts ?
>Lead time for modifying gear legs?

Any others?
 
I don't think you're going to see a line form to comply with the SB. Some will, some won't. It very well could be a time consuming mod though.
 
Vern said:
Many factors to consider:
>Stabilizing aircraft while awaiting gear parts with NG removed
>Nose wheel pant-will it need modification?
>Removing those pesky bolts!
>Will tow bars still fit?
>Will Van's have enough parts ?
>Lead time for modifying gear legs?

Any others?
Click to expand...

I have done this retrofit and have the following to submit:

1) I had the luxury of using two aircraft grade jacks, placed under the firewall with padded blocks to lift and support my airplane. A well placed padded sawhorse right under the firewall should also do the trick. Not a big problem.

2) Not sure about the pants, as mine were not on the old leg/fork when I made the change.

3) Bolt removal was no biggie for me

4) Towbars still fit

5) I am sure that Van's will anticipate the demand appropriately

6) I had to have my new gearleg match drilled for the bolt hole, as mine is a 6A and was drilled in assembly with my engine mount during manufacture. Not so now with the 7A/9A. Sent my old leg to Langair and got my new leg, all drilled for my engine mount within 1.5 weeks. Might be a bit of a longer wait now that this bulletin has come out. Time will tell.



In a nutshell, this changeover was not a painfull process at all.
 
I am very close to getting my airworthyness inspection done. Will the DAR insist that I comply with the SB before first flight? ( I do want to comply - just not right this minute!)

Im also interested in whether I will need to rework my nose wheel fairing if anybody has the info on that (MORE fiberglass?)

thanks

erich
 
LifeofReiley said:
I don't think you're going to see a line form to comply with the SB. Some will, some won't. It very well could be a time consuming mod though.
Click to expand...

Vans claims this is a MANDATORY Service Bulletin to be implemented on or before the next 100 hourly/annual. Presumably no authority has the power to enforce the implementation of this Bulletin but if you have a nosegear failure and you have not upgraded there is always the risk that your insurance company may not pay up.
 
I did the conversion and the brackets for the wheel pant are totally different. This means that you can either drill out the rivets and put the new brackets on or do a whole new pant. The good news is that once you are finished with this mod the plane is not only safer but the wheel pant comes off quickly without pulling the wheel like the previous setup. As for the tow bar, I concur that mine still fits.

Last weekend my wifes dad was getting current in my 9A because he hasn't flown it in a while so I was sitting right seat. He has around 2300 hours complex for what it is worth and flies around 150 hours a year in his Comanche. Of course he flew it great but as we exited the runway at Gustine, CA there is a ridge between the runway and the taxiway. It is quite small, but I usually creep over it as slowly as I can just to be careful. He hit it at walking speed or just a little faster though. I could feel it and knew that some work had occurred under the front and was scared to look when we stopped at the fuel island. Well the good news is that nothing broke this time! However there is clear evidence of the movement that took place. Picture this if you can. When I change the oil on the plane it doesn't matter what the heck method is tried I always make a mess when removing the horizontally mounted filter. This oil drips down the back of the engine and motor mount as I'm frantically chasing it with a rag. There is always some that gets into the top of the web portion of the motormount where that receives the gear leg fairing. This is like a little trap that catches oil with no way to get it all out. So then over the next few flying hours it will find its way into the nose gear leg fairing were it runs down and onto the top of my wheel pant in flight. I hate this but have accepted it as a part of having my plane. With this explained the rest of this will hopefully make sense. With the slight film of oil inside the gear leg fairing and apparently the intersection fairing also where at the cowl to gear leg fairing junction, evidence of the movement was recorded! As the gear leg bent backwards the rear portion of the leg fairing moved up into the back of the intersection fairing . In other words the gear leg was flexing back and as the back of the wheel pant curves up towards the bottom of the cowl the leg fairing moves backwards and up at the same time. Then it apparently returned to the original position and most likely very quickly. This felt just the way it did the time the damage occurred for the record. Anyway the film of dirty oil on the inside of the upper intersection fairing left a clear mark on the gear leg fairing showing just how much movement had occurred. At the very trailing edge of the leg fairing where it touches the upper intersection fairing there is now a oil mark that goes down about 3/8" to 1/2" and angles its way to the front of the gear leg fairing. It is as clear as day how much this thing moved this time and since I didn't have a camera with me last weekend I left it exactly like this in the hanger to photograph it this weekend. So tomorrow morning I'll take some pictures. So the million dollar question is did the new design save the nose gear? Did it bend enough to have made the old style fork and nut dig into the ground or not? I'll never know but I sure am glad for the mod! Truthfully I had decided to never post on this subject again because it seemed to be doing nothing but hurting the hobby that I love. But now with the new policy from Van's it might help others to quantify the flexing by seeing these pictures with my oil stain marking the spot. So if interested check back for pictures.

Best,
 
Bryan Wood said:
Picture this if you can. When I change the oil on the plane it doesn't matter what the heck method is tried I always make a mess when removing the horizontally mounted filter. This oil drips down the back of the engine and motor mount as I'm frantically chasing it with a rag.
Click to expand...


Here is a tip to prevent this. Take a used one gallor bleach bottle or similar bottle and cut the bottom of it off. It then becomes very flexible. Keep the cap on the bottle and maneuver it around the oil filter so that it is under it and against the engine. Loosen the filter a bit so that your can turn it by hand. Use a punch and poke a hole on the top side of the filter. Rotate the filter one half turn and punch another hole so that the residual oil will drain out of the filter into the bottle. When it stops dripping, unscrew the filter and let it drop into the bottle. Use a rag to wipe off the area where the filter was attached and then maneuver the bottle with the filter in it out from behind the engine. Presto! Filter removed and no oil on the engine.
 
jamescone said:
Here is a tip to prevent this. Take a used one gallor bleach bottle or similar bottle and cut the bottom of it off. It then becomes very flexible. Keep the cap on the bottle and maneuver it around the oil filter so that it is under it and against the engine. Loosen the filter a bit so that your can turn it by hand. Use a punch and poke a hole on the top side of the filter. Rotate the filter one half turn and punch another hole so that the residual oil will drain out of the filter into the bottle. When it stops dripping, unscrew the filter and let it drop into the bottle. Use a rag to wipe off the area where the filter was attached and then maneuver the bottle with the filter in it out from behind the engine. Presto! Filter removed and no oil on the engine.
Click to expand...

Sure beats the ol "plastic bag around the oil filter trick" THANKS!

Do I need to remove the bleach first? ;)
 
I did the mod a long time ago..

I accomplished the mod to my 7A about a year ago (?) and had no problems at all. Sent the leg to Languir to be cut and rethreaded and installed the new fork. Fairing fit the new fork perfectly and did not require new brackets or anything. I did cut the fairing higher to take advantage of the additional clearance the new leg offered. The only thing additional I think vans should offer is a new fairing that takes full advantage of the mod. If you do a search on this subject I posted pics before of my modded fairing. The mod took about 2 weeks with the shipping and everything. I know some folks cut and rethread the leg themselves, if you did this you could do it in day or two.
 
why is 9A nosegear more limited?

After looking through Vans charts, I notice that the 9A nosegear is limited to 325 lbs and the 6A/7A/8A are allowed 375 lbs. Does anyone know why?
 
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Oil Filter

The bleach bottle idea is great. Just put a baby diaper under it all. Pampers work great and will catch all drips!
 
Mistake?

I really think Van's should have thought about this one a little longer. IMHO, Van's is digging a big hole around themself. Van's does not need to be issuing SB's on any aircraft as they do not manufacture aircraft; Just a bunch of pieces and parts that if worked with long enough, could be coerced into such an animal. A builder and an insurance company are going to get sideways on this issue one day and an attorney is going to have a field day with Van's. Hmmm, which side of the fence does Van's want to be on here? Then they will find them self in the hole they dug, looking up and well... we've all heard about these kind of events. The End.
 
Sorry, OT, but since someone asked...

Geico266 said:
Sure beats the ol "plastic bag around the oil filter trick" THANKS!

Do I need to remove the bleach first? ;)
Click to expand...

I've found that a square piece of aluminum foil works very well too. Work it under the filter, form it into a tray, remove the filter, carefully wad up the foil containing the spilled oil and remove the ball...no runs, no drips, no punching a hole in the filter.

Sorry didn't think this warranted another thread topic.
 
I know that working with new parts is easier. Lightening any part in the nose on -7A fixed-pitch Sensenich planes only exacerbates the tail heavy tendency, however small the weight reduction. I just had a wild thought because the old fork appears to be beefier than the new and would still be beefier after this mod.

Since the objective of this whole exercise is to raise the height of the fork by 1", how about reworking the old fork. Remove the bottom bushing, cut 1" off of the bottom, make an angle cut from the axle flange on each side to meet the cut made across the bottom (with a suitably rounded intersection to relieve any stresses), file and smooth the cut edges, re-insert the bottom bushing, remove old grease zerk and screw a plug in to fill that hole, drill and thread a new hole for the zerk midway up the front of the fork. Of course, the nose gear leg would still have to be shortened and reworked.

Big disadvantage: You end up with a fork of unknown strength, but is beefier than the new purchased fork.

Big advantage: No changes need to be made regarding fairing attachment or stop bracket attachment.

Any thoughts?

Mike
 
LifeofReiley said:
I really think Van's should have thought about this one a little longer. IMHO, Van's is digging a big hole around themself. Van's does not need to be issuing SB's on any aircraft as they do not manufacture aircraft; Just a bunch of pieces and parts that if worked with long enough, could be coerced into such an animal. A builder and an insurance company are going to get sideways on this issue one day and an attorney is going to have a field day with Van's. Hmmm, which side of the fence does Van's want to be on here? Then they will find them self in the hole they dug, looking up and well... we've all heard about these kind of events. The End.
Click to expand...

Agreed, the Van's community is starting to look more 'certified' every day and it concerns me from an insurance standpoint; especially the way that some insurers are trying to find any excuse they can to avoid a payout these days. IMO, it has a lot to do with the large numbers of Vans designs flying and Van's commendable desire to keep accidents to a minimum.

At least the FAA hasn't gotten their wringing sweaty hands involved in it...yet.
 
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IowaRV9Dreamer said:
After looking through Vans charts, I notice that the 9A nosegear is limited to 325 lbs and the 6A/7A/8A are allowed 385 lbs. Does anyone know why?
Click to expand...

I am wondering this as well. The 9A limit is 325 lbs, and the others are 375 lbs. Presumably the nose gear does not know which airplane it's mounted on. It may be that Van's has incorporated some dynamic limitations that we are not aware of. For example, the gear positions are different on the aircraft:

Moment Arms (approx):
9a nose gear: 34.3". Main gear: 90.9"
7a nose gear: 39.1". Main gear: 93.6"

Of course, it may be just a more arbitrary limitation. I wish Van's had explained it.

V
 
vlittle said:
I am wondering this as well. The 9A limit is 325 lbs, and the others are 375 lbs. Presumably the nose gear does not know which airplane it's mounted on. It may be that Van's has incorporated some dynamic limitations that we are not aware of. For example, the gear positions are different on the aircraft:

Moment Arms (approx):
9a nose gear: 34.3". Main gear: 90.9"
7a nose gear: 39.1". Main gear: 93.6"

Of course, it may be just a more arbitrary limitation. I wish Van's had explained it.

V
Click to expand...

Maybe in their mind it would deter folks from bolting Lycoming 360's on the nose of a 9. :eek:
 
Wonder if RV6 s/n001 has complied

Just got back from getting my wife trained with Mike Seager in RV6 s/n 001. We were talking and Mike estimated he does 40-60 circuits per day 4 times per week in this plane which has over 4500 hours on the airframe. Thats over 9500 circuits per year with "newbie" pilots manhandling and over controling and bouncing and... you get the picture. NO nose wheel failures on this bird and Mike says if you fly it properly there will be no problems.

Regardless, I will comply with the SB at the next annual but I wont be smiling.

BTW-my wife transitioned in the right seat and did a great job.
 
Some what unsatisfying

Seriously FEA analysis was good, I know a little bit about FEA, but the final conclusion was some what unsatisfying, "good enough?". :eek:


We know what we mostly already knew:

-If the fork does not dig into dirt/ground, the gear will not dig-in, thus no flipping. No dig, no flip. (makes sense)

-Pilot, skill, don't land hard, bounce or drive into a ditch. (makes sense)

-Tire, pressure, keep it inflated on the high side. Less air pressure less fork/ground clearance. (obvious thought, may be Van should redesign for a 5x5 tire and take the drag hit?)

-Surface, rough or soft surfaces with hills and valleys reduce gnd/fork clearance. (fair to say they implied more risk on soft fields than hard. So RV-A's are not back country Bush planes, we knew that. My input is TAXI slow on soft fields.)

-Nose, weight, keep it light, prop & engine. (the statistical data they quoted did conclusively show a direct correlation to me. analytically it was shown more nose gear load = less grd/fork clearance. makes sense but light prop/eng combos flipped as much or more, I suppose for other reasons?)

-Wheel fairing drag/tire catching is an insignificant factor, a minor contribution to reducing fork/gnd clearance. (I kind-a-sort-of disagree. I seem to recall a few cases, which although did not result in a full flip, it involved taxi on flat hard surface and clearly the fairing catching the tire causing the start of a full dig-in. Vans previous SB or RVator article warned about having sufficient tire/fairing gap.)

-New gear & folk seems like a goodness thing, providing more folk/ground clearance. We shall see. If or when the first RV-A flips with the new gear/fork, proper tire pressure & light prop and engine, taxing on smooth surface & flips, it will throw a monkey wrench into the works again.

FEA is good, but there are limitations. Who ever did the analysis seems to have a good basic understanding of FEA, but there is some user skill involved. The computer will pump out a solution, but it needs to verified with actual structural test, if only for small displacements. I would rather see a full scale test rig, testing a gear to destruction. You could vary gear load, tire press and surface. That would validate the computer model.
 
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The FEA model assumes that the legs were all heat treated properly. I'm somewhat skeptical that that is the case. There are several failures on asphalt which don't make sense from the conclusions drawn in the study and point to "soft" steel in these cases IMO. I don't think this is the case in the vast majority of incidents and especially flip over on grass however.

What was the problem with the original (early) leg design? Maybe I missed that part.

I agree that the new fork design will give more nut clearance on bumpy grass surfaces- this can only be a good thing if you fly off grass. I've got a late leg and I don't even taxi on grass so I feel ok, since the fork is for clearance.

The new fork will not end A model flips IMO, just reduce them. Hit a big enough hole or land on the nosewheel and it's over, pun intended.:(

If I flew off grass, I'd have the new fork for sure. I'm glad Van's stepped up and offers this for A drivers anyway. Do we know if 001 has ever had a gear problem. Didn't one of these early ones have a collapse?
 
rv6ejguy said:
SNIP

What was the problem with the original (early) leg design? Maybe I missed that part.

SNIP
Click to expand...

There were fatigue cracks happening, and a few flipped over after the leg broke. Van did a lot of dynamic testing on a rotating cam like machine. The new leg has a different profile.
 
SB Questions

Has anybody looked into this? Why do you need to shorten the leg? If the reason for the modification is to get 1" additional ground clearance and the new fork provides the proper geometry then why not add a 1" spacer on top of the new fork. No cutting of the existing gear leg and as an added benefit you will have an additional inch of prop clearance. I have a friend that has a new fork assembly on order and I will have an opportunity to check out this theory myself when we install / remove the fork assembly.

Russ Keith

RV9A Slow Build
 
Metalman9A said:
Has anybody looked into this? Why do you need to shorten the leg? If the reason for the modification is to get 1" additional ground clearance and the new fork provides the proper geometry then why not add a 1" spacer on top of the new fork. No cutting of the existing gear leg and as an added benefit you will have an additional inch of prop clearance. I have a friend that has a new fork assembly on order and I will have an opportunity to check out this theory myself when we install / remove the fork assembly.

Russ Keith

RV9A Slow Build
Click to expand...

Russ, very interesting idea. I would think the nose wheel fairing would not fit well, if at all, without major modification. But, the idea is interesting.
 
By adding a spacer you would effectively lower the nosewheel and make keeping it off the ground even harder.

Roberta
 
robertahegy said:
By adding a spacer you would effectively lower the nosewheel and make keeping it off the ground even harder.

Roberta
Click to expand...

Roberta, perhaps he meant the 7/9A's only? I suspect adding an inch to the nose gear height on a 7 or 9A would still put the aircraft in a lower angle of attack on the ground as compared to a standard 6A.
 
Oh well... We had a few nose wheels this weekend land on a grass strip; a couple of 6A's and an 8A and I watched them very close on landing and taxi. All of the pilots were elevator up, stick back and it did not look to even be an issue. Oscillation, well yes... signs of damage or flipping... not at all. Even on taxi out and takeoff, nothing out of the norm.
 
Using spacer

If you were to use a spacer with the new style fork on the longer axle you would be increaseing the AOA while on the ground and leave a 1 inch long 'ugly part' sticking above the nose wheel pant. You would also have to figure out a way to mount the nose fork swivel stop. You could possible just drill a new 5/16" hole an inch lower on the axle, but that would intersect the 7/8" weight reduction hole drilled up the middle of the axle.

I guess it is all possible, but might not be worth the hassle and trouble compared to the cost of shipping and the $75 it cost to get the nose gear cut off and re-thread.
 
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