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  #1  
Old 04-23-2005, 04:08 PM
martinkh martinkh is offline
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Default Lets do some real R & D!!! Takeoff Performance

Guys, those of you with flying canards, can you help us get some data to make our esoteric theorizing a little more real? If my proposed experiment should be modified to make it more useful, lets get any changes out of the way so that we can maybe get a couple of you to record the same data the same way so that us non-flying guys can make better plans.

I am clueless at real world performance of these planes, so could someone with a copilot, or great multi-tasking ability please record some data on take off for me?

The experiment:

Do a normal full throttletake off, do not use brakes to hold back to get speed up.
Every 10 seconds jot down your rpms & IAS untill your prop reaches top rpm or you are 50 feet off the ground. This data from a stock cozy with a lycoming would give us a great baseline to compare all other engine setups. For the rotorheads, jot down engine rpm and do the reduction and post. If you could give us your top IAS and RPM at level flight at (this is totally from my hat) 8,000 feet, that would be beautiful.
When you post, state your starting altitude, air temp, plane type, engine, prop specs, cargo (you included) weight and reduction if applicable.

The results should help with the HP vs Torque discussion, and provide data for picking redrive ratio, prop specs, and engine suitablity.

If someone using an engine with known dynometer properties were to do this, it would be huge!!!!! If one Lycoming and one rotary guy did this the same, or even folks with the same engine, different prop, or same prop, different engine, we could substitute some brain time for trial and error work.

Last edited by martinkh : 04-23-2005 at 06:32 PM.
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  #2  
Old 04-23-2005, 06:20 PM
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John Slade John Slade is offline
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I'd be happy to collect the numbers. Unfortunately Tracy's still underwater and doesnt expect delivery of his new EC2 boards until the end of the month
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Old 04-24-2005, 04:59 PM
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rv6ejguy rv6ejguy is offline
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Default Takeoff run

If you must debate this further, be my guest. A normal 13B atmo Wankel with a fixed pitch prop in a fully loaded Cozy on a hot day will take in excess of 2000 feet to leave the ground and climb at 500 fpm if you are lucky. If you find that acceptable performance, that is an option. If you are looking for something better:

1. Atmo Renesis, Lyc or Cont
2. turbo Diesel with +++ boost
3. turbo Wankel, Sube, Cont/ Lyc

In that order of performance available.

An atmo 13B just does not produce enough torque or hp at 4000-4500 rpm to get the job done, Maybe 110-130 hp. Gonna be lame without any testing required.
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Old 04-24-2005, 05:17 PM
martinkh martinkh is offline
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Quote:
Originally Posted by rv6ejguy
If you must debate this further, be my guest. ... Gonna be lame without any testing required.
I am editing my post here as my first response was rather testy.

I am requesting data. I am requesting that folks suggest improvements to my list of data to be collected. I want it easy so that I can get some cooperation from folks who would rather just fly and have fun, so that we can figure out what is needed to help figure out how to match the prop to the engine to the redrive. You ASSUME that all I want is to prove an atmo 13b or some such, as it not the case.

Since your entire post was based on false assumptions of my intent, and is off topic, I wish you would delete your post, and I will delete this one, I don't want the request in the original post lost in the noise.

Last edited by martinkh : 04-24-2005 at 05:43 PM.
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  #5  
Old 04-24-2005, 09:46 PM
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John Slade John Slade is offline
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Quote:
An atmo 13B just does not produce enough torque or hp at 4000-4500 rpm to get the job done
I'm not sure that's entirely true. There are a number of non-turbo 13b's flying quite happily - Paul Connor for one. Having watched Tracy's "atmo" Renesis RV climb like a banshee and disappear from sight at 200 kts I'm still open to discussion on that one.
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Old 04-24-2005, 10:01 PM
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Quote:
Originally Posted by John Slade
I'm not sure that's entirely true. There are a number of non-turbo 13b's flying quite happily - Paul Connor for one. Having watched Tracy's "atmo" Renesis RV climb like a banshee and disappear from sight at 200 kts I'm still open to discussion on that one.
But is Paul launching on 4000-4500rpm? Also, reading his post carefully, it seems his reference of 'atmo 13B' does not include the Renesis cause he lists Renesis as one of the better solutions..
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Old 04-24-2005, 10:17 PM
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rv6ejguy rv6ejguy is offline
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Default RV and Cozy

Quote:
Originally Posted by John Slade
I'm not sure that's entirely true. There are a number of non-turbo 13b's flying quite happily - Paul Connor for one. Having watched Tracy's "atmo" Renesis RV climb like a banshee and disappear from sight at 200 kts I'm still open to discussion on that one.
An RV is an entirely different story, different airfoil, more wing area, diffrent characteristics. I can be off in 350-400 feet if I want to abuse it. Even fixed pitch RVs are off in 600 easy and have a very high angle of climb. Isn't Tracy using a VP prop? Atmo 13B Cozies are flying of course but I bet takeoff and climb are nothing to write home about with fixed pitch props. Anyone out there flying one that would like to give us the numbers?
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  #8  
Old 04-24-2005, 10:22 PM
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No, Tracy has a fixed-pitch prop on his Renesis with a 2.85:1 redrive and a 74?-inch prop.

There's 1 NA-13b Cozy flying, still trying to work off the 40 hours.
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