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Bipe versus mono at altitude

Old 01-09-2012, 03:27 AM
  #1  
cartercg
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Default Bipe versus mono at altitude

Hi,

The 2013 World Champs will be hosted at Zebula in South Africa. The altitude at this location is 4200 feet. Here in Johannesburg in South Africa we fly at around 5500 feet. With the thinner air the speed of the plane becomes more critical. One needs to slow the plane down to fly on around 150m without being too rushed to fit the schedule in the box. The reduced lift at altitude makes this more challenging. I've watched bipes fly at our local altitudes and they seem to handle the altitude better in that they seems to be able to fly slower without the same magnitude of problems as a mono when flown slower (excessive dropping of the tail on KE, barrelling in rolls etc).

So what's the opinion regarding optimal setups at altitude:

a) Normal mono is fine
b) We'll see lots of large T-Cans on monos, or
c) Bipe is the way to go, especially with all of the rolling elements in the F13

I'm wondering if I should take the plunge and go the bipe route. I'm told the bipe rudder authority is excellent but that it does not handle cross winds as well as a mono. Who's flown both mono and bipe at altitude and what do they think?

Regards
Clint
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Old 01-09-2012, 06:35 PM
  #2  
blikseme300
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Default RE: Bipe versus mono at altitude

Where in SA is Zebula? I don't know these new names.

Bliksem
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Old 01-10-2012, 01:33 AM
  #3  
cartercg
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Default RE: Bipe versus mono at altitude

Hi, Zebula is in the Waterburg area 2 hours north of Johannesburg. It is a fantastic venue with championship golf course, game viewing and full size runway. Check out the following website for more info. It promises to be a fantistic venue for the next world champs. The misses won't mind you going flying given all the facilities available!

http://www.zebula.co.za/index.aspx?id=1

Regards
Clint
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Old 01-10-2012, 06:13 AM
  #4  
Mvelez
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Default RE: Bipe versus mono at altitude

We fly in Bogota, Colombia  at 8100 ft and we can state that the difference is huge. You need to fly faster and of course change your rates, expos, mixes, everything if you come from sea level.

once we got to the USA for the worlds, we had to make a new model on the radio and retune everything. It is much harder to keep constant speed up here since the model dives like a stone on downlines, and the plane stalls a lot on snaps, so you need speed and power to keep the tail from not going down. It is also a little harder to stop the reversing spins. it is much harder to keep the tail from not dropping on rolling maneuvers, specially on the horizontal ones. A good thing is that it teaches you a lot on throttle management.

of course it takes a higher speed to take off and land.

A little more wing area and a little thicker airfoil would help planes behave better. What is absolutely clear to me, is that current F3A planes have lots of troubles flying at this altitude. Conditions are very different. I also think that a Bipe in altitude is a good option, even with the crosswind handicap, the final result might end positive. 


As you can imagine, we take every possible chance to fly at lower altitudes, and I have around three different setups for different alttitudes (in Colombia you can go from 900 ft above sea level to 8100 ft in a three hour drive). In our experience, flying at Zebula altitude, is not very much difference to what most people is used to fly at sea level. there will be changes for sure but not substantial. 

now flying at 8100 ft. that is another story... YOU ARE ALL WELCOME!

regards

Marcelo Velez
Colombia
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