Originally posted by Hubb
OK, this is a legit question 
I have read many bits and peices about the newer widebody planes for competition. It seems that the goal is to acheive good slow pace to the whole sequence. uplines, downlines, straight and level flight.
my question is what makes this possible and in what combination.
widebody design - more physical displacement of the air?
drag - such as fixed gear, cowl cheeks?
wing area and wing design?
overall weight - 9lbs vs 11lbs?
2-stroke vs 4-stroke?
prop selection?
I fly a Focus/Webra 1.45. it seems that compared to a Smaragd/YS 1.40 that the Focus flys much faster.
so 'cmon all you Jedi masters, please share with us your knowledge.
Hubb
Widebody - No I dont think this is important for slow flight, maybe has a marginal effect on downlines but that can be acheived on a small fuse through other methods.
Gear/Cheeks - Again no, the cheek cowls are largely for looks and do nothing except maybe to help cool the motor if they are cutout. Most fixed gear is quite aerodynamic and would contribute little to the drag.
Wing Area/Design - Definately the design of the airfoil on the wing and stab will effect drag. I think this is a biggie, a properly designed wing has the potential to really aid in the downline breaking.
Weight - Again yes, a lighter plane is much easier to get a nice contant speed flight than a heavier one. I am not talking about 9.25lbs - 9.75 lbs, thats really insignificant for most models, but 9.75 lbs to 11 lbs now that is a difference.
2-stroke/4-stroke - I dont think so, the two strokes have come a long way. I think it takes more effort to set them up to get similar breaking etc as a four stroke but if properly setup and flown right I dont think its a key element anymore. The four stroke is easier to throttle manage than a two stroke though IMO.
Prop Selection - Yes most definately. I just tried a three blade 15x13W on my 140DZ and it didnt break any better than a 16.5x12W!! You need to try lots of props, and find one that gives lots of up power and good down breaking. Diameter is your friend when it comes to downlines. Now getting the right prop for that may not put you in the noise limits so you sometimes need to compromise a litte. That is where good throttle management comes into play.
If I was to rank the importance of the ones I said yes to it would be something like this I think
1. Throttle management!
2. A light model
3. Propellor selection
4. Design, shape etc of the wing/stab/fuse
In preparing for the Worlds I have spent a lot of time trying to acheive that elusive constant speed flight. The correct use of throttle is key! In this day with our massively powerful motors its really easy to overuse the throttle and really get your plane moving at warp speed. Really focus on the throttle when flying and using only enough power to maintain your speed, I think you will find that your constant speed flying starts to improve almost immediately.
Anyways those are my thoughts on it