Flaperons for Bobcat
01-15-2003 | 09:16 PM
#1
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From: Scotland, UNITED KINGDOM
Flaperons for Bobcat
Has anyone tried using Flaperons for takeoff on their Bobcat?
I fly my jets from a small model airfield – 100 ft of tarmac, so need maximum lift to get the model off the runway as quickly as possible. Obviously the model is heavier on takeoff with full fuel and smoke oil on-board, so I thought it might be a good idea to have both Ailerons set to 20 degrees down for takeoff (Flaperons), mid position for normal flying and both Ailerons up for landing (Spoilerons).
Has anyone tried this and what were the results? Did it shorten the takeoff run? What angles/travel did you set?
I fly my jets from a small model airfield – 100 ft of tarmac, so need maximum lift to get the model off the runway as quickly as possible. Obviously the model is heavier on takeoff with full fuel and smoke oil on-board, so I thought it might be a good idea to have both Ailerons set to 20 degrees down for takeoff (Flaperons), mid position for normal flying and both Ailerons up for landing (Spoilerons).
Has anyone tried this and what were the results? Did it shorten the takeoff run? What angles/travel did you set?
01-15-2003 | 10:03 PM
#3
My Feedback: (8)
Flaperons for Bobcat
You don't want to deflect the ailerons down on a Bobcat as when deflected down they drive the nose down. You will want to deflect the ailerons up for landing approximately 2 - 3 degrees for landing. This will enable you to maintain a nice nose high angle of attack on final. The final point is do not deflect the ailerons down as flaperons on the Bobcat.
I think I would look for a longer runway to fly off of. I can't imagine setting down and getting stopped in 100 feet with a 19 pound jet. I am thinking you would go through a lot of tires. Don't you have a nice grass field you could fly off of?
John Redman
Team BVM, Jet Cat USA, Shutlze Chargers
I think I would look for a longer runway to fly off of. I can't imagine setting down and getting stopped in 100 feet with a 19 pound jet. I am thinking you would go through a lot of tires. Don't you have a nice grass field you could fly off of?
John Redman
Team BVM, Jet Cat USA, Shutlze Chargers
01-16-2003 | 12:38 AM
#4
Senior Member
My Feedback: (11)
Flaperons for Bobcat
I have used both up and down flaperons.
When I had the little RAM 500 in my Bobcat, I followed Tony Frackowiak's suggestion, and set up some mixes for flaperons. IIRC it was something 10 degrees for mid, 18 degrees for full flaperons. I used the mid position for both takeoff and landing. It did require up elevator mixed in.
After I upgraded to the P120, the flaperons were not draggy enough to slow the aircraft down the way I wanted (much higher residual thrust), so I changed to using up flaperons and down elevator). This raises the nose of the aircraft more, so that the whole underside of the aircraft now produces more drag.
However, one interesting point is that while the up flaperon helps slow the aircaft down, it also increases the landing speed, according to my local aerodynamicist, Bob Parks of the jet-list fame. (I gave up trying to understand fluid dynamics a long time ago, so I take his word for it... I personally don't notice the difference)
Your runway sounds like the last one I flew from in Scotland - Dunfermline Model Aircraft club, with a runway that was about 80 ft long, 8 foot wide... and moguls beyond. Prior to that I was in a club in Invergordon that had an enormous ex-WWII bomber airfield to fly from - talk about going from one extreme to the other !
Gordon
When I had the little RAM 500 in my Bobcat, I followed Tony Frackowiak's suggestion, and set up some mixes for flaperons. IIRC it was something 10 degrees for mid, 18 degrees for full flaperons. I used the mid position for both takeoff and landing. It did require up elevator mixed in.
After I upgraded to the P120, the flaperons were not draggy enough to slow the aircraft down the way I wanted (much higher residual thrust), so I changed to using up flaperons and down elevator). This raises the nose of the aircraft more, so that the whole underside of the aircraft now produces more drag.
However, one interesting point is that while the up flaperon helps slow the aircaft down, it also increases the landing speed, according to my local aerodynamicist, Bob Parks of the jet-list fame. (I gave up trying to understand fluid dynamics a long time ago, so I take his word for it... I personally don't notice the difference)
Your runway sounds like the last one I flew from in Scotland - Dunfermline Model Aircraft club, with a runway that was about 80 ft long, 8 foot wide... and moguls beyond. Prior to that I was in a club in Invergordon that had an enormous ex-WWII bomber airfield to fly from - talk about going from one extreme to the other !
Gordon
