RV-6A nose gear with Anti-Splat device fails

[rhill]

Thread Drift?

Regardless of how they happen,Nose gear collapses happen,enough of them to be a concern.A data base,however flawed needs and should be started,refined with time,The Facts,Just the Facts,No conclusions or personal bias.I know of two collapses that were never reported and I'm sure there are more.how to validate an off the books event is problematic as these are some of the same guys who are Dieing to keep there medical.The less who know about it the better.Perhaps they shouldn't be counted or handled as a unknown percentage or left out altogether.
RHill

 

[Snowflake]

Did Van really say the 7A would get off quicker than the 7?

I'm pretty sure they said the A models would *land* shorter than the non-A models, as they could be rotated to a higher AOA at touchdown. Take-off distances shouldn't vary, as the TW model will climb just as steeply as the -A model and rotating to that angle would happen just as fast in either model?

 

[rvbuilder2002]

More thread drift

I'm pretty sure they said the A models would *land* shorter than the non-A models, as they could be rotated to a higher AOA at touchdown. Take-off distances shouldn't vary, as the TW model will climb just as steeply as the -A model and rotating to that angle would happen just as fast in either model?

Take-off distance a function of airspeed and the maximum AOA that can be achieved at the moment the airplane is rotated to leave the ground.
If the A models are able to rotate to a higher AOA on the ground (they are), then they are capable of leaving the ground in a shorter distance (I am not meaning to say that any and all pilots can safely do so).

Bottom line... anything AOA related, that can influence landing distance can have the same influence on take-off distance.

Technically, a tail dragger RV can land about as short as a the equivalent tri gear model, if the pilot is willing to plop it on with the tail wheel having touched first (in flight there is nothing to limit the tail dragger from achieving the same AOA as the trigear, like there is when they are on the ground).

 

[Snowflake]

If the A models are able to rotate to a higher AOA on the ground (they are), then they are capable of leaving the ground in a shorter distance (I am not meaning to say that any and all pilots can safely do so).

And yet... The Van's website shows takeoff performance for a 150HP RV-6 as needing 550 feet, and a -6A as needing 560 feet. I blame the difference on the extra drag on the nosewheel. Or maybe it just gets off faster because it looks better. (Kidding! Really!)

http://vansaircraft.com/public/rv6perf.htm

Technically, a tail dragger RV can land about as short as a the equivalent tri gear model, if the pilot is willing to plop it on with the tail wheel having touched first (in flight there is nothing to limit the tail dragger from achieving the same AOA as the trigear, like there is when they are on the ground).

I wish I could say I had no idea what you were talking about... But I suspect a number of my early landings were, well, just as short as if I had a nosewheel...

 

[csmith3603]

Nose Wheel

The nose wheel dangles with no physical control besides
the ground rudder & power?

 

[pierre smith]

Yep, just like a Grumman or Cirrus.

Best,

 

[Andy Hill]

Technically, a tail dragger RV can land about as short as a the equivalent tri gear model, if the pilot is willing to plop it on with the tail wheel having touched first (in flight there is nothing to limit the tail dragger from achieving the same AOA as the trigear, like there is when they are on the ground).

I would say you could abuse the brakes better in the A than the taildragger... you don't have to worry about a nose over - well until the nose gear fails which is probably not the intended way of achieving a short landing roll

Given most RVs have not stalled in the 3 pt attitude, the taildragger can land more slowly since as you say, TW first is an (almost) valid technique, but landing on the tail bumper on the A probably is not

 

[Snowflake]

Given most RVs have not stalled in the 3 pt attitude, the taildragger can land more slowly since as you say, TW first is an (almost) valid technique, but landing on the tail bumper on the A probably is not

The catch is that the main gear on a NW model is about two feet further back than on the TW model. Even without hitting the rudder on the ground (which would hit first), the NW RV's will rotate to a higher nose-up attitude, and hence can land just that tiny bit slower. In theory. It does require very precise flying and an intimate knowledge of your aircraft to fly your rudder that close to the ground though. A number of local NW RV's have skids attached to their aft fuselage "just in case". I don't know if that's a standard part or not.

 

[flyvans.com]

by default, there is no tail skid.
even the tie-down ring, that we keep installed in the back, does not completely protect the rudder from hitting ground (while main gear on ground) in such an extreme attitude.
during the fuel flow at attitude test we had to complete before first flight, we had to be careful so the aircraft didn't tip backwards / hit rudder bottom.

the rv accelerates/lifts off so quickly, that i see no reasonable way to hit the tail on takeoff. you had to be aiming for it and then you would likely end up in an extremely dangerous attitude shortly after. another scenario would be a porpoising grass runway, but then, the nosegear is likely more of a concern...

at landing, hitting the rudder would be slightly more probable, such in gusty conditions or the like, but even here, it would have to be extremely wild/dynamic and uncomfortably close to stall if not beyond.

the only cases where i have heard/seen rudder bottoms hitting, was at fuel stations with people standing on the steps and lots of baggage/aft cg.

 

[Andy Hill]

We had an RV-6A visit our strip that used the tail bumper landing technique It flew out again after some tactical "unbending" of the bumper from the rudder.

I'll withhold the picture to protect identity

 

[Flyist]

Anti-Splat Nose Gear Mods & My RV-8A

My apologies to adding to a slightly old thread but I feel the following needs to be added to the discussion;

I purchased a finished 8A last fall that sat for several years that had no nosegear mods, not even Vans fork upgrade. It had serious nosegear shake/chatter/vibration at low taxi speeds and the beginning of the take-off roll. Watching the nosegear in operation, it appeared to be attempting to "roll or knuckle under" up to an inch or more before snapping forward again, a aft-fore chatter motion if you will all occurring very rapidly. This was very unsettling!

I insured that Vans recommended fork breakout torque and wheel bearing torque was correct. With the spec wheel bearing torque the aircraft was difficult to pull/push by hand on the ground. I trialed backing off slightly on the wheel bearing torque which made ground handling easier and lessened the "taxi-chatter". However, upon removing the wheel from the fork both the fork and the wheel bearing spacer had serious galling. I immediately got the Anti-Splat wheel bearing mod. Problem solved! Smooth taxi, no chatter, no visible nosegear movement. I now have full confidence in my nosegear. For added peace of mind I installed Vans fork upgrade and Anti-Splats gear leg mod. (There is always the odd hole in a grass strip to contend with.)

After reading many posts and accounts of nosegear failures (especially the one that failed on a hard surface runway at a crossing runway junction), spending most of the day sitting beside runway 36 at Oshkosh studying -8 vs -8A landings and all the gear bouncing, shaking, shimmying and even pivoting/spinning nosegears upon touchdown (yes, very loose breakout torques), plus my own -8A experiences, I have come to the conclusion that the Vans wheel bearings/seal is the largest mechanical factor/catalyst in these nosegear failures. Essentially, by loosening torque on wheel bearings to allow for low wheel spin resistance permits nosegear fork flex, wheel spacer to fork galling thus resulting in momentary wheel lockup. This starts the chain of events that leads to Nosegear failure... The Anti-Splat WheelBearing Mod solves this problem.

 

[petersb]

My apologies to adding to a slightly old thread but I feel the following needs to be added to the discussion;

I purchased a finished 8A last fall that sat for several years that had no nosegear mods, not even Vans fork upgrade. It had serious nosegear shake/chatter/vibration at low taxi speeds and the beginning of the take-off roll. Watching the nosegear in operation, it appeared to be attempting to "roll or knuckle under" up to an inch or more before snapping forward again, a aft-fore chatter motion if you will all occurring very rapidly. This was very unsettling!

I insured that Vans recommended fork breakout torque and wheel bearing torque was correct. With the spec wheel bearing torque the aircraft was difficult to pull/push by hand on the ground. I trialed backing off slightly on the wheel bearing torque which made ground handling easier and lessened the "taxi-chatter". However, upon removing the wheel from the fork both the fork and the wheel bearing spacer had serious galling. I immediately got the Anti-Splat wheel bearing mod. Problem solved! Smooth taxi, no chatter, no visible nosegear movement. I now have full confidence in my nosegear. For added peace of mind I installed Vans fork upgrade and Anti-Splats gear leg mod. (There is always the odd hole in a grass strip to contend with.)

After reading many posts and accounts of nosegear failures (especially the one that failed on a hard surface runway at a crossing runway junction), spending most of the day sitting beside runway 36 at Oshkosh studying -8 vs -8A landings and all the gear bouncing, shaking, shimmying and even pivoting/spinning nosegears upon touchdown (yes, very loose breakout torques), plus my own -8A experiences, I have come to the conclusion that the Vans wheel bearings/seal is the largest mechanical factor/catalyst in these nosegear failures. Essentially, by loosening torque on wheel bearings to allow for low wheel spin resistance permits nosegear fork flex, wheel spacer to fork galling thus resulting in momentary wheel lockup. This starts the chain of events that leads to Nosegear failure... The Anti-Splat WheelBearing Mod solves this problem.

I agree, and so does Allan of Antisplat.

I used the Matco axle mod and removed one of the bearing seal lips, as per Matco, to reduce bearing rolling resistance.

Most of the tip overs occur after the aircraft pitches up, for whatever reason, and then comes down. This seems to occur even at walking speed on all types of surfaces.

 

[Bavafa]

I used the Matco axle mod and removed one of the bearing seal lips, as per Matco, to reduce bearing rolling resistance.
.

Installed the same axle mod a few years ago and have seen great results just as described here.