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  #1  
Old 10-07-2017, 10:28 AM
Tom Martin Tom Martin is offline
 
Join Date: Jan 2005
Location: Ontario, Canada
Posts: 1,288
Default RV14 climb test

In Canada one of the requirements for a final flight permit is a climb test. This is a steady rate of climb for three minutes. It is a non event for any RV or rocket but for low power airplanes on hot days it is a check in the system to make sure the plane can climb with a full load.
The test is done with a full Gross Load
We had 300 lbs of fuel
Pilot and Crew member 423 lbs
Aft baggage load of 100 lbs.
This made a gross weight of 2050 lbs, which is Van's recommended Gross

All was good and at 111 knots IAS we averaged 1150 ft/min.
Yes I could have climbed at a much higher rate of climb but there was no need

The interesting thing, for me, was that with that load, to land within the C of G range we had to have 118 lbs of fuel remaining, or 20 gallons.

The moral is, yes you can load it to gross but check your numbers for low fuel limits.

The plane handled the load great with no serious handling issues at either end of speed envelope. I landed with about 35 gallons of fuel into a stiff 10 knot gross wind with no handling issues.

The baggage load was made up of 25 lbs of lead shot and a combination of cat and dog food!

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  #2  
Old 10-07-2017, 10:32 AM
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bkervaski bkervaski is online now
 
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Awesome, I bet that was fun.
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  #3  
Old 10-07-2017, 11:34 AM
n982sx n982sx is offline
 
Join Date: Apr 2010
Location: Chicago, IL
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Hi Tom,

Reading your numbers regarding CG had me wondering if I had calculated all my CG cases correctly. I went back to my spreadsheet and did some new calculations and I have not found any indication of CG issues with zero fuel.

I do have a trike, not a tail dragger but I was not really close to a CG limit at any zero fuel weight. In replicating your weights and having no fuel, I get a CG at 87.7 inches. Still a half inch within limits.

My build is pretty standard. I don't recall from your previous posts but does your airplane have any significant changes from a stock 390 and Hartzell prop?

Just curious if your numbers may be outside of normal or are in fact normal.
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  #4  
Old 10-07-2017, 11:57 AM
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M McGraw M McGraw is offline
 
Join Date: Dec 2012
Location: Greenback, TN
Posts: 313
Default RV-14 Taildragger

If I use the numbers Tom used, I get the same result. However, reducing the baggage to 85lbs allows the fuel to burn down to zero and stay within CG. With that said 423lbs of pilots/passenger is pretty impressive. The standard FAA pilot/passenger is 170lbs each. My wife and I can carry full fuel, full 100lb baggage and still not exceed 2050lb and stay within CG at full and zero fuel. very capable aircraft, but please do pay attention to the warning from Tom.
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  #5  
Old 10-07-2017, 12:24 PM
BobTurner BobTurner is offline
 
Join Date: Dec 2011
Location: Livermore, CA
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Same caution applies to the -10: If you takeoff near either cg limit, then as you burn fuel the cg moves toward that limit. Always check cg at takeoff and landing configurations. (If you write an Excel spreadsheet it's easy to program it to always do a zero fuel cg calculation.)
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  #6  
Old 10-08-2017, 02:19 PM
KeithB KeithB is offline
 
Join Date: Mar 2014
Location: Granbury, TX
Posts: 93
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I built a tricycle model. When I did the flyoff, I used 150 lbs in the baggage area and the weight required in the passenger seat to reach gross. According to my calcs, the plane was never out of CG, even at zero fuel, and I found the handling to be delightful - just much less nose down trim required for landing with full flaps. My problem was forward CG. With just me, at 150 lbs and no baggage, the plane is "technically/numerically" out of CG forward. For early phase 1, I added 20 lbs to baggage to make sure I was in. Later in Phase I, I experimented with 0 baggage (i.e. out of CG forward). With full flaps, there was not enough nose-up trim to hold 75 kts - I needed ever so slight aft stick pressure. However, since that's the way I prefer to trim for landing anyway, it wasn't even an inconvenience.
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  #7  
Old 10-08-2017, 09:14 PM
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Ed_Wischmeyer Ed_Wischmeyer is offline
 
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Location: Savannah, GA
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170 lb average passenger weight is an obsolete number. The ASTM number for LSAs is 190. And average weights really only have meaning when you're considering a number of folks, not just one or two.
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  #8  
Old 10-08-2017, 09:44 PM
n982sx n982sx is offline
 
Join Date: Apr 2010
Location: Chicago, IL
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Quote:
Originally Posted by KeithB View Post
My problem was forward CG. With just me, at 150 lbs and no baggage, the plane is "technically/numerically" out of CG forward. For early phase 1, I added 20 lbs to baggage to make sure I was in.
Yes, this is an issue to watch out for with a very light pilot. My wife, who is not a pilot and has no intention to be one, is 110 pounds and would need to add 10 pounds of ballast in the baggage area to fit within the forward CG limits if she were to fly solo.

>130 pounds works in my airplane without ballast however.
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Last edited by n982sx : 10-09-2017 at 03:51 PM.
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  #9  
Old 10-09-2017, 01:01 PM
Berchmans Berchmans is offline
 
Join Date: Nov 2009
Location: Anchorage, Alaska
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Well, I am glad to see that I am above average in one category anyway...working of that though
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  #10  
Old 10-09-2017, 04:50 PM
helinut helinut is offline
 
Join Date: Apr 2017
Location: Pasco, WA
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So does someone have a generic spreadsheet they can share for the 14? I'm very much looking at building one. I flew the demo at Van's and loved it.

I'm 245 pounds and I'd say I have a few passengers I'd want to take that are 240 ish or less pounds. It appears with full fuel I should have 510 pounds of useful load. Anyone have CG issues with carrying that much as crew? If we dropped 10 gallons, could I get away with putting that weight in the baggage area?

Thanks!
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