islandmonkey
Well Known Member
Something that caught my eye earlier today was an advert from Flyboy Accessories.com. I took a look at the RV Rocket Steering Link:
http://www.flyboyaccessories.com/store/index.php?main_page=product_info&cPath=66&products_id=242
and noticed that the castor angle of the red tail wheel (look at the larger picture) looks negative to me. This may be an illusion caused by camera angles and I am not criticising this product, but I want to draw your attention to how bad negative camber angles on a tail wheel can be.
Having owned a Super Cub for a number of years, I went through the stage of suffering severe tail wheel shimmy when landing on tarmac or concrete. Landing on grass was not a problem and as most of my landings were on grass, I did not notice the problem until eventually, I landed on a hard runway. In the summer, if the grass was short and the earth was hard from lack of rain (unusual mostly in the UK and Germany) then I noticed a slight shimmy, which reduced if I took pressure off the tail by putting the stick forward. On hard tarmac or concrete runways, the shimmy was alway there and only reduced slightly by relaxing back pressure on the stick.
The solution and explanation to the problem I found here:
http://www.pierceaero.net/tws.php
http://www.pierceaero.net/techdata/tws.jpg
Take a look at these links to Steve and Gilbert Pierce's website. The explanation is explained eloquently.
I replaced my tail wheel spring and ensured a positive camber angle and Voila! my Cub was no longer a shopping cart with a dickey wheel.
http://www.flyboyaccessories.com/store/index.php?main_page=product_info&cPath=66&products_id=242
and noticed that the castor angle of the red tail wheel (look at the larger picture) looks negative to me. This may be an illusion caused by camera angles and I am not criticising this product, but I want to draw your attention to how bad negative camber angles on a tail wheel can be.
Having owned a Super Cub for a number of years, I went through the stage of suffering severe tail wheel shimmy when landing on tarmac or concrete. Landing on grass was not a problem and as most of my landings were on grass, I did not notice the problem until eventually, I landed on a hard runway. In the summer, if the grass was short and the earth was hard from lack of rain (unusual mostly in the UK and Germany) then I noticed a slight shimmy, which reduced if I took pressure off the tail by putting the stick forward. On hard tarmac or concrete runways, the shimmy was alway there and only reduced slightly by relaxing back pressure on the stick.
The solution and explanation to the problem I found here:
http://www.pierceaero.net/tws.php
http://www.pierceaero.net/techdata/tws.jpg
Take a look at these links to Steve and Gilbert Pierce's website. The explanation is explained eloquently.
I replaced my tail wheel spring and ensured a positive camber angle and Voila! my Cub was no longer a shopping cart with a dickey wheel.