Noisy, rattling nose wheel .... what’s normal?

[IBob]

18 hours ago, Blueadventures said:

It is not easy to keep the nose wheel up on the Nynja, like Nev says its to do with the main undercarriage axle location.  You will see the the Savannahs for example land and the nose wheel is easy to hold up; so their mains axle is further forward.  I have seen Savs low on fuel and loaded with cargo sit down on their tail; and this would be the lighter nose wheel weight and the mains axle pivot point and the mass of cargo behind the axle.

Blueadventures, re the Savannah, that would depend on what model (and, of course, loading):
The hugely experienced allround pilot who test flew my S noted in his report:
"Abrupt throttle closure in combination with low and reducing airspeed during landing flare...can see a loss of elevator control and potential  for the nose wheel to touch down firmly. Recommend trickling off power...alternatively, maintain 35kts into the landing flare."

 

I fly often on my own, with perhaps 40litres in the tanks, no baggage and my adjustable seat 1 notch back from the front position. And (too) many of my landings have seen the nose wheel touch down firmly.

 

I added VGs to the elevator underside, which improved elevator authority some, but there remains a distinct difference between the Sav VG, where the nose comes off readily and may be held there at sub-takoff speeds, and the S where the nose does not come off so readily.

 

Then recently I made up a 10kg sandbag and placed it in the centre of the baggage area. And suddenly I have an aircraft that no longer drops the nose wheel on.

 

I should add that my S is a standard build and all the calcs show my solo flight configuration as well within the forward limit according to the POH.

[Blueadventures]

25 minutes ago, IBob said:

Blueadventures, re the Savannah, that would depend on what model (and, of course, loading):
The hugely experienced allround pilot who test flew my S noted in his report:
"Abrupt throttle closure in combination with low and reducing airspeed during landing flare...can see a loss of elevator control and potential  for the nose wheel to touch down firmly. Recommend trickling off power...alternatively, maintain 35kts into the landing flare."

 

I fly often on my own, with perhaps 40litres in the tanks, no baggage and my adjustable seat 1 notch back from the front position. And (too) many of my landings have seen the nose wheel touch down firmly.

 

I added VGs to the elevator underside, which improved elevator authority some, but there remains a distinct difference between the Sav VG, where the nose comes off readily and may be held there at sub-takoff speeds, and the S where the nose does not come off so readily.

 

Then recently I made up a 10kg sandbag and placed it in the centre of the baggage area. And suddenly I have an aircraft that no longer drops the nose wheel on.

 

I should add that my S is a standard build and all the calcs show my solo flight configuration as well within the forward limit according to the POH.

XL

[BrendAn]

On 28/08/2022 at 10:40 AM, APenNameAndThatA said:

You’re not supposed to use the nose wheel for taxiing, 

this has made me scratch a bald spot on my head. 

[turboplanner]

57 minutes ago, IBob said:

Blueadventures, re the Savannah, that would depend on what model (and, of course, loading):
The hugely experienced allround pilot who test flew my S noted in his report:
"Abrupt throttle closure in combination with low and reducing airspeed during landing flare...can see a loss of elevator control and potential  for the nose wheel to touch down firmly. Recommend trickling off power...alternatively, maintain 35kts into the landing flare."

 

I fly often on my own, with perhaps 40litres in the tanks, no baggage and my adjustable seat 1 notch back from the front position. And (too) many of my landings have seen the nose wheel touch down firmly.

 

I added VGs to the elevator underside, which improved elevator authority some, but there remains a distinct difference between the Sav VG, where the nose comes off readily and may be held there at sub-takoff speeds, and the S where the nose does not come off so readily.

 

Then recently I made up a 10kg sandbag and placed it in the centre of the baggage area. And suddenly I have an aircraft that no longer drops the nose wheel on.

 

I should add that my S is a standard build and all the calcs show my solo flight configuration as well within the forward limit according to the POH.

When you round out the nose should be slightly up and you will sink onto the mains.

With persistent practice you can hold the nosewheel off a certain distance - say 300 mm.

My first instructor wanted me to set the throttle when turning base then leave it alone until after the roundout, and that would eliminate the abrupt throttle closure. What he wanted and what I have given aren't necessarily the same of course, but it's a good starting point.

[facthunter]

Some have small amounts for and aft, but most are in the wing. naturally where they are swept back there's more trim shift. It's all done for each flight usually graphically with zones  which have varying C of G effects. You enter at the top with the Planes zero fuel weight and Cof G. Generally the C of G is adjusted by the  cargo hold contents or Passenger seating.. Fuel in the wing makes for a lighter structure. Some loading specifies all above a certain specified weight must be FUEL and some planes have a minimum weight for flight where ballast may have to be carried.. Some wing tip tanks fuel must be consumed before the PNR is passed because it requires electric pumps to get it out of those tanks. Nev

[facthunter]

Turbo some planes aren't happy to hold off like the Piper Comanche which has laminar flow  wings  and may drop out of the sky if you hold off high or may drop a wing. They tend to be flown on and often a smaller nosewheel tyre is fitted to avoid premature contact in say crosswind conditions where a bit more speed may be used. Nev

[Markdun]

Found the knocking culprit. The main shaft that rotates in the plastic bushed aluminium pillow blocks bolted to the firewall. Rotates smoothly but there is about 1mm end float so the whole front wheel assembly (except for the pillow blocks bolted to the firewall) will go up and down 1mm as load is applied and removed which happens when the nose comes down after you hit a bump.  With a fast taxi I couldn’t notice it.... mainly because the whole plane rattles.  I’m still trying real hard to understand why ppl prefer noise wheelers instead of conventional.

Edited September 4, 2022 by Markdun
Pressed send by mistake.

[facthunter]

Tail wheels can get shimmy. Then you have to be a real cowboy and taxi with the tail up. Nev

[Markdun]

Nah. Just take the tail wheel off, ie convert to a tail skid. Only issue you may occasionally have to hop out to re-aim the aircraft. Had to do this at Temora once to line up for T/O on the grass.   But yes, bitumen certainly is tough on tail wheels, particularly the shopping trolley brand.

[turboplanner]

18 minutes ago, Markdun said:

Found the knocking culprit. The main shaft that rotates in the plastic bushed aluminium pillow blocks bolted to the firewall. Rotates smoothly but there is about 1mm end float so the whole front wheel assembly (except for the pillow blocks bolted to the firewall) will go up and down 1mm as load is applied and removed which happens when the nose comes down after you hit a bump.  With a fast taxi I couldn’t notice it.... mainly because the whole plane rattles.  I’m still trying real hard to understand why ppl prefer noise wheelers instead of conventional.

In 2005, a levee bank over capped in Melbourne next to a trailer park with 600 people. I warned that the 70 year ARI would produce serious flooding and the levee needed to be raised. The Park manager said "BS, I've been here 17 years and it's never looked like flooding", so the Council took the easy way out and did nothing.  In 2011, the park had to be evacuated, 15 houses were damaged and one woman lost all her possessions.

 

Tail wheel aircraft grew up in "all-over" fields. You could look at the wind sock then take off into wind or land into wind regardless of which way it was blowing.

As the demand for airfields increased it was common  for airstrips to be built; pilots often had to take off, land and taxy with crosswinds of various angles and speeds.  There was a chance of weathercocking and it became good form to have a helper walk along holding a wing tip to prevent this. Tail wheel aircraft also had a habit of nosing over onto the prop, particularly under braking and sometimes without brakes.

Towards the end of WW2, designers started fitting tricycle undercarriage because it avoinded having to find a helper, and the nose wheel contact was enough to prevent weather cocking, and brake technology could advance to dramatically reduce the length of landing roll Touch down points were more accurate, also helping to increase the working landing length. It also eliminated the old wheeler or three pointer debate with the mass distribution allowing the mains to do their job and a smaller nose leg and wheel because the pilot could land on the mains at landing speed and allow speed to wash off and the aerodynamics lowered the nosewheel with less landing force than the mains.

Today our airstrips are narrower because we don't keep running off them, so like the trailer par manager, someone in a tail wheel aircraft may never have been hit by the gust that turns him sideways and spears him into the drain. When it does happen he can say "Well the nose wheel would have stopped that."

[APenNameAndThatA]

On 28/8/2022 at 2:00 PM, Markdun said:

Ehhhh? When I did the conversion to nose wheel the instructor said to me as we were slowing down and about to turn off the runway (bitumen) that 'its ok for you to lower the nose wheel to the ground gently now'.  So if a nose wheel isn't for taxiing what exactly is its function; perhaps the same as a rubber duck?

I was mostly joking. 

[APenNameAndThatA]

On 4/9/2022 at 11:44 AM, Markdun said:

Found the knocking culprit. The main shaft that rotates in the plastic bushed aluminium pillow blocks bolted to the firewall. Rotates smoothly but there is about 1mm end float so the whole front wheel assembly (except for the pillow blocks bolted to the firewall) will go up and down 1mm as load is applied and removed which happens when the nose comes down after you hit a bump.  With a fast taxi I couldn’t notice it.... mainly because the whole plane rattles.  I’m still trying real hard to understand why ppl prefer noise wheelers instead of conventional.

The tail wheel pilots’ superior skill fails to compensate for their poor choice of aircraft, and they crash more than tricycle pilots on taking off and landing. That’s no joke. 

[Markdun]

Don’t know the stats & I wouldn’t disagree.  Might be different for operations flying out of and into a paddock compared to a bitumen runway. I would hazard a guess it will to a far greater extent depend on the pilot’s experience and currency.  I’m more than comfy flying a nosewheel off a paved runway.... I’d even admit it feels easier than a tail wheel aircraft. But on the grass and mud & ruts...?  I’ve been doing some fast taxies with the J200 and I find it a bit of a challenge.... compared to my tailgdraggers. No light tap dancing on the rudder pedals to keep it straight like the tail draggers... more like heavy pushing steering a rugby scrum... that is until the nose wheel comes up.

[facthunter]

When tailwheelers were the norm there weren't lots of incidents. In a strong wind you can PIN a tailwheeler on if the prop has enough clearance. it's no big deal if you start  on them.  Nev

[BrendAn]

18 hours ago, Markdun said:

Don’t know the stats & I wouldn’t disagree.  Might be different for operations flying out of and into a paddock compared to a bitumen runway. I would hazard a guess it will to a far greater extent depend on the pilot’s experience and currency.  I’m more than comfy flying a nosewheel off a paved runway.... I’d even admit it feels easier than a tail wheel aircraft. But on the grass and mud & ruts...?  I’ve been doing some fast taxies with the J200 and I find it a bit of a challenge.... compared to my tailgdraggers. No light tap dancing on the rudder pedals to keep it straight like the tail draggers... more like heavy pushing steering a rugby scrum... that is until the nose wheel comes up.

I think you're being a bit dramatic about nose wheels.  I am only a learner but I find the Jabiru easy to steer and control. I like that setup because the vision is excellent. 

[spacesailor]

AND THERES THE POINT.

Nose dragers have 100%, better forward vision  than those old timers of yesteryear,  or is it Now Millennium. 

Just the thought of Hanging outside the cockpit to keep your eyes to the front while taxying, is on the same learning curve as jumping out of a good aeroplane with your hand grasping your chute release handle .

spacesailor

[Markdun]

Now you guys should get some experience.  I’ve about 1500 hours total time and probably a bit over 30 hours on nose ploughers. I admit I don’t have a lot of experience on nose ploughers. But it is just plain untrue, wrong, incorrect that tail draggers have poor fwd vision. My Cygnet SF2A with the tail on the ground has far better fwd vision than the Jabiru, the Tecnam Bravo, a Cessna 150 & caravan all with their nose wheel on the ground. I admit the Corby has less fwd vision with its tail on the ground than the Jab..... pretty much the same as the Tecnam (nosewheel down).  Further the tail draggers (at least the ones I’ve flown) lift the tail within 20m from the start of a take-off roll, and all the tailwheelers I’ve flown with tailwheel up have had better fwd vision than any nose plougher I’ve flown with its nosewheel down. And then there’s what happens when the nose plougher rotates & lifts it’s nosewheel....pretty much no fwd vision along the airstrip ....& that’s at speed. The opposite happens for the tail dragger...as you speed up better vision.  I’d much rather run into the pothole going slow than hit the unseen wombat at speed. In the air the LG is pretty irrelevant to vision, except I note the Tecnam Bravo & the Cessna caravan suffer from astronaut complex in having a ginormous panel for all those fancy screens and switches and thingos which block the view for normal sized people.  In short, ‘some taildraggers’ have poor fwd vision when taxiing slowly with the tail on the ground... but not all.  I’d also say that in attempting to land short in a paddock (say from an engine failure)...an outlanding, the vision fwd on the Jabiru landing slightly tail down is no better than the Corby.  Don’t get me wrong, I’m not anti nose ploughers... I’ve just got one... the Jab200. As I’ve said before it’s probably pilot experience and currency which is more important.  Two big differences: first the wheel base is much longer in a taildragger. As such the pitching moment is much less when you roll over a bump or indentation. Second, a quick perusal of the RAA-aus incidents shows many a nose plougher damaged from the nosewheel digging in during an outlanding. It may well be the same logic of the fact that brown horses eat less than white horses in Australia (its true!), but I don’t think so.

[BrendAn]

29 minutes ago, Markdun said:

Now you guys should get some experience.  I’ve about 1500 hours total time and probably a bit over 30 hours on nose ploughers. I admit I don’t have a lot of experience on nose ploughers. But it is just plain untrue, wrong, incorrect that tail draggers have poor fwd vision. My Cygnet SF2A with the tail on the ground has far better fwd vision than the Jabiru, the Tecnam Bravo, a Cessna 150 & caravan all with their nose wheel on the ground. I admit the Corby has less fwd vision with its tail on the ground than the Jab..... pretty much the same as the Tecnam (nosewheel down).  Further the tail draggers (at least the ones I’ve flown) lift the tail within 20m from the start of a take-off roll, and all the tailwheelers I’ve flown with tailwheel up have had better fwd vision than any nose plougher I’ve flown with its nosewheel down. And then there’s what happens when the nose plougher rotates & lifts it’s nosewheel....pretty much no fwd vision along the airstrip ....& that’s at speed. The opposite happens for the tail dragger...as you speed up better vision.  I’d much rather run into the pothole going slow than hit the unseen wombat at speed. In the air the LG is pretty irrelevant to vision, except I note the Tecnam Bravo & the Cessna caravan suffer from astronaut complex in having a ginormous panel for all those fancy screens and switches and thingos which block the view for normal sized people.  In short, ‘some taildraggers’ have poor fwd vision when taxiing slowly with the tail on the ground... but not all.  I’d also say that in attempting to land short in a paddock (say from an engine failure)...an outlanding, the vision fwd on the Jabiru landing slightly tail down is no better than the Corby.  Don’t get me wrong, I’m not anti nose ploughers... I’ve just got one... the Jab200. As I’ve said before it’s probably pilot experience and currency which is more important.  Two big differences: first the wheel base is much longer in a taildragger. As such the pitching moment is much less when you roll over a bump or indentation. Second, a quick perusal of the RAA-aus incidents shows many a nose plougher damaged from the nosewheel digging in during an outlanding. It may well be the same logic of the fact that brown horses eat less than white horses in Australia (its true!), but I don’t think so.

good points

 

[facthunter]

A C-180 has pretty crook forward vision with the tail on the ground. It's surprising what little vision you actually need to land on a runway. Flying through a wisp of low cloud will cover the window with fine water drops and you can only see out the sides.. Lifting the tail up quickly causes a lot of gyroscopic effect which can catch you out particularly if you have a bit of crosswind from the wrong side as well.. Nev

[Markdun]

Sorry, correction. The fact is ‘Brown horses eat more than white horses in Australia’.

[BrendAn]

2 hours ago, BrendAn said:

good points but most of the aircraft on the planet are nosewheel for a reason.

 

 

 

[facthunter]

It's easier to insure them for ONE. Easier to load pax and cargo. More directionally stable if you don't transfer weight to the nosewheel. Better forward vision when taxiing. Many larger planes used nosewheels before WW2 particularly in the USA. Became pretty universal after the 50's. Nev

Edited September 8, 2022 by facthunter

[RFguy]

Brendan, let me know how you go when landing a nosewheel aircraft in rutted  mud on an outlanding.... compared to a tailwheel...... most likely, the nose wheel will be ripped off unless you have plenty of tail and can keep the nose up until the bitter end. 

[spacesailor]

But the t,d will nearly Always  dig it,s prop into the dirt, just when you think, " got it " safely down.

Then those ruts catch your mains & over you go .

Iv,e been watching the movies.  LoL

( I did say,  the OLD ONES )

spacesailor

[BrendAn]

45 minutes ago, RFguy said:

Brendan, let me know how you go when landing a nosewheel aircraft in rutted  mud on an outlanding.... compared to a tailwheel...... most likely, the nose wheel will be ripped off unless you have plenty of tail and can keep the nose up until the bitter end. 

Have to wait till I get a licence Rf. Jabirus are known for folding up the nose wheels I heard. I don't plan on landing mine anywhere that can happen.