Tire size and weight make a difference

[Roger Larson]

Hi Paul. Are you talking about the stock Revolt tires the Aero Classic 21×8.00-6? I have been flying those tires for about 4 years. The only issue i have had with them is the bullhead stickers that we get in Arizona. I was wondering about going to a 6 ply and spoke with Larry and he gave his concerns with the heavier tires. The Aero Classics have been out of stock for a while and wonder if you have any thoughts of other tires to put on a Revolt?

[Paul Hamilton]

Aero Classic may be the lightest. You can shop for any brand so I went with Michelins but my observation has been that even the same size tire can have a significant difference in weight which I have noticed……. Look at the weights to establish a base line to work from. Never thought we would have trouble getting tires.

[Larry Mednick]

The “nose slam” phenomenon is very real. Without an elevator to control pitch attitude at touchdown like an airplane, the carriage swings back as the wheels touch, and the more rotating mass and the larger diameter they are, the more affect they will have. This is why we don’t use the 22” tires on the REVOLT on hard surfaces. The 600s and 700s aren’t horrible when you go to something like a Michelin (we have tried them all) but those tires are only 15-17”. By the time you go to a 21” tire, you don’t want more than 4 ply and you don’t want tubes because the moment of inertia is so much larger.

I ran into a fellow that had 29” tires on his trike and I asked him if he ever landed on hard surface with it. He said no. I told him to be very careful if he ever does.

[Peter Bronson]

Larry, I am having some continuing nose drop issues with my Revolt when landing on pavement. The mains come in smoothly but I am unable to hold off the nose wheel to grease the landing. Am I better off flying it on the runway as opposed to holding it off as long as possible to reduce the swing thru? On grass, there is not an issue.

Thanks

Pete

[Larry Mednick]

Hi Pete, a few factors… Having at least 20 PSI in the 21″ tires will reduce the contact patch size, the larger the contact patch with softer tires, the faster the tire will tend to spool up. The chirp we often hear is the time it takes for the tire to go from 0-landing speed. The longer the chirp, the longer the tire takes to accelerate which drastically reduces the aft force swinging the carriage backwards. In the grass it’s even longer. Adding power at touch down will typically increase the time it takes to put the weight onto the tires which again will slow the spool up of the tires. Smaller and or lighter tires may not slow the spool up, but will have less affect when they do.

Next is where is the bar at point of the mains touching down. If the bar is “pinned” forward you can expect the nose to drop uncontrolled regardless of tire size. So holding a flare off too long with a trike can be detrimental to lowering the nose down nicely. However, most often the nose comes down abruptly BUT the control bar is not all of the way out as the nose wheel touches. This is pilot error in my opinion, since there was control available, but unused. The most common 2 reasons for not using this range of AOA is not leaning forward and not being able to reach well. The second trick is to have the control bar in forward motion as the mains touch. This will allow the control bar to CONTINUE forward as the pilot seat is literally yanked back away from the controls. So holding the controls steady in one spot as the mains touch means that when the pilot seat gets pulled back, the pilot is actually pulling the control bar back without moving the bar. When the bar is traveling forward it allows the bar to keep moving forward at that critical moment. If you watch a no handed landing you will see the control bar appear to lunge forward when the mains make contact without the pilot’s input. See the 0:47 mark on video https://youtu.be/pxWXCbB3pHU

Lastly, if you can get the bar all the way out at the same moment the nose wheel touches the ground, that is a text book landing in my opinion and the nose should USUALLY touch soft and hopefully not bounce. This can be done with or without power.

Remember once the mains are down and the nose wheel is still in the air and the bar isn’t pinned all the way out, the tire’s moment of inertia, contact patch size and landing surface no longer affect the nose being lowered to the ground. And again I increase AOA to lower the nose down softly, although the popular way seems to be to decrease the AOA to do so which I do not personally subscribe to.

[Peter Bronson]

Thanks Larry. You have given me some ideas to work on. Really enjoying the Revolt.

[Roger Larson]

I Weighed the aero classic tires yesterday and it weighed in at 11 pounds. i have a tube in my nose wheel and that weight is 1.5 pounds. This does not include the weight of the rim. When landing, a high nose wheel can bounce easier than a low nose wheel. I trim a bit faster and land flatter. My ground speed is slightly higher but that is better with crosswinds like we get all the time here. I have been running 18psi in all my tires because i also land on dirt roads and fields. I almost always land with power other than to practice engine out landings. Not much but a little that allows me to grease my landings better. I have almost no wear on my tires after 4 plus years. I want to change them out because of time not wear. I also run slime in my tubeless tires because of the bullhead stickers we have here. In strong crosswinds i like to barely let my tires touch and have almost zero weight on them until the trike is exactly where i want it to be before landing. Larry has it mastered and its a bit hard for the rest of us to meet or exceed OEM. 🙂

[Larry Mednick]

Roger, trim speed and touchdown speed do not affect the height of the nose wheel when the mains touch. That is controlled by the geometry of the carriage. It is possible to swing the carriage which can cause the nose wheel to rise higher because of the swing with over controls during the flare.

In bowling there are many ways to get a strike, but only pro bowlers can get 10 in a row and all use a similar technique. Want to put the nose wheel down gently and consistently there is only one way to do it. Want to get consistent strikes, there is only one way to do it. And like bowling, if you change your technique don’t expect instant results. But with practice, the sky is the limit and total control over the nose wheel is possible in light enough. conditions.

Bar pinned as the nose wheel touches is like the spin on a bowling ball…

Here is the technique again. It’s a transferable skill with consistent results for a 400 hour pilot like Wayne.Wayne’s New REVO

https://youtu.be/UKQHPdQVegEWayne’s New REVO
https://youtu.be/UKQHPdQVegE

[Paul Hamilton]

Yes I wish I could replace tires from old age but with primary training I do endless landings. Teaching students how to land, spinning those tires up time after time, I go through tires like fuel and spark plugs.