Toe-in or toe-out on a warbird?
#27
RE: Toe-in or toe-out on a warbird?
Just to be clear here. Toe-in and toe-out refer to the wheels being convergent and divergent (rather than parallel) relative to the direction of travel, yes? What is it called, then, if the wheels are convergent ("splayed out" on the bottom) or divergent ("splayed out at the top") perpendicular to the ground? This was the case with the undercarriage geometry on several WWI aircraft, two examples, being the Fokker EIII and Sopwith Camel. Many of the Sopwith aircraft used a split axle with "independent suspension" and when sitting on the ground, the wheel have an awkward splayed out at the bottom "broken axle" appearance. With the EIII the UC geometry normal held the wheels below the UC center post so they would "splayed out at the top" when not under full compression (as for example on a landing).
Anyway, I've never used toe-in or toe-out (as described above) on any WWI model, but many of them (most of them?) end up having some degree of the situation I've described here.
Anyway, I've never used toe-in or toe-out (as described above) on any WWI model, but many of them (most of them?) end up having some degree of the situation I've described here.
#28
Senior Member
RE: Toe-in or toe-out on a warbird?
A Sopwith Camel at rest has negative 'camber' for the top of wheels lean toward the fuse. That was a fine explanation of 'wheel engineering' but still doesn't address caster changes with stab angle of attack changes (stab going up or going down). For fun make up a dummy set of wheels on an axle and play with it for anecdotal evidence.
Some of my landings have had the end result of negative camber and toe out!
Some of my landings have had the end result of negative camber and toe out!
#29
RE: Toe-in or toe-out on a warbird?
For all the engineering crap that gets spouted and always funny to see some people cling to academics like its the next coming of Jesus.....what matters is how the actual plane responds in real life. A lot of cases, as has been attested to by a great number of people in this thread, what works in theory isnt what works at the field. Some planes react better to toe-in, while others may be OK with a touch of toe-out.
And yes...there IS a debate. Someone claiming there is no such debate because of what they believe, doesnt make it fact that a debate doesnt exist. Some people find toe-in works for them, while others find toe-out works for a particular plane better. Whatever.
I prefer tow-in as it works on the planes I fly.
And yes...there IS a debate. Someone claiming there is no such debate because of what they believe, doesnt make it fact that a debate doesnt exist. Some people find toe-in works for them, while others find toe-out works for a particular plane better. Whatever.
I prefer tow-in as it works on the planes I fly.
#30
RE: Toe-in or toe-out on a warbird?
ORIGINAL: kahloq
For all the engineering crap that gets spouted and always funny to see some people cling to academics like its the next coming of Jesus.....what matters is how the actual plane responds in real life.
For all the engineering crap that gets spouted and always funny to see some people cling to academics like its the next coming of Jesus.....what matters is how the actual plane responds in real life.
#33
RE: Toe-in or toe-out on a warbird?
ORIGINAL: abufletcher
Especially when the engineering is taken from multi-ton full-scale aircraft.
ORIGINAL: kahloq
For all the engineering crap that gets spouted and always funny to see some people cling to academics like its the next coming of Jesus.....what matters is how the actual plane responds in real life.
For all the engineering crap that gets spouted and always funny to see some people cling to academics like its the next coming of Jesus.....what matters is how the actual plane responds in real life.
You dont see ANY full scale plane flying at 45oz/sq in wing loading. What you do see is how many POUNDS per square in on a full size plane. You can preach engineering crap for full size planes all you want....dont mean squat unless your flying a full size plane.
But of course, you just HAVE to be absolutely correct and no one can differ in opinion or even present real world experience thats different....if they do...well...they're just not smart enough right? Cuz they arent buying into whatever it is that YOU say?
#34
RE: Toe-in or toe-out on a warbird?
ORIGINAL: kahloq
Multi ton full scale aircraft are NOT the same and do NOT behave the same as small scale representations on the ground.
Multi ton full scale aircraft are NOT the same and do NOT behave the same as small scale representations on the ground.
#36
RE: Toe-in or toe-out on a warbird?
MY thoughts: A plane's response to toe-in and toe-out do follow the physics as was put forth. However, there are a lot of variables affecting ground characteristics of our RC models that are not accounted for when looking at just toe-in and toe out. I have seen that most wheels are not a perfect fit to the axles and have a lot of play. Many wheels are not drilled perfectly perpendicular to the desired line of rotation and wobble. On most models, the drag on the main wheels are often uneven. Just spin the wheels on any of your planes and it will be the very unusual instance when the two free-wheel the same. Another is that a lot of planes are not very well balanced laterally (though I think this is probably a more minor contributor to ground handling issues?). Also, it's tough to ensure that the angles of both wheels are set up exactly the same in both toe and camber. Landing gears also may flex and torque in ways that effect ground handling. All these variables are harder to determine and account for when setting up your plane for ground handling. Usually, you will need to resort to a more trial and error approach. I suspect that many times, two of the same models may end up using different amounts of toe (in or out) in order to achieve the same ground handling characteristics.
Scott
Scott
#37
My Feedback: (6)
RE: Toe-in or toe-out on a warbird?
When I'm landing one of my R/C planes, I'm not sure, but I think my toes are pretty much "out" - not quite like a duck's feet, but definately NOT pidgeon-toed. I'm not actually sure, because I'm usually concentrating pretty hard on the plane, it's speed, the wind, and stuff other than how my feet are placed toe-wise.
For War Birds, I think I'm mainly just really really happy if the landing gear actually deployed...
Hope this helps.
-Skip
For War Birds, I think I'm mainly just really really happy if the landing gear actually deployed...
Hope this helps.
-Skip
#38
Banned
RE: Toe-in or toe-out on a warbird?
" When I'm landing one of my R/C planes, I'm not sure, but I think my toes are pretty much "out" - "
Not me. My toes pretty much stay with my knees, and I lock them solidly together to keep them from knocking:-))))))))))))))))
Les
Not me. My toes pretty much stay with my knees, and I lock them solidly together to keep them from knocking:-))))))))))))))))
Les
#40
Senior Member
My Feedback: (26)
RE: Toe-in or toe-out on a warbird?
I had a 1/4 scale H9 J3 Cub and it came with toe out. This puzzled me so I went to an airport were there was a full scale J3 Cub and it also had toe out. I asked the FBO about it and his answere was that is the way it was designed and it works. Point is if you have a scale WWII model and wonder about the axle placement go to the real thing and copy it. My FW 190 has toe-in and it track just fine hereas my Extra 260 has no toe in or out.
#41
My Feedback: (6)
RE: Toe-in or toe-out on a warbird?
A lot does depend on the geometry of the gear. My 1/4 scale cub likes a little toe-out and negative camber as it sits static, but what actually happens when the tail lifts up is the main gear flexes, the camber changes, and the toe-out actually "dissappears". My P-51 is just the opposite, it likes a little toe-in because when the main gear is under load, they flex outward almost to the point of toe-out.