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Brake Release to 10000' w/IO360 FP Prop

David-aviator said:
As per last year, I issue a challenge to anyone with a CS prop to do likewise just to compare numbers. :)
Click to expand...


OK, I took the challenge today. Clouds finally cleared enough for me to do a crosswind runway takeoff and straight-ahead climbout to 10,000'. Preferred runway would have put me into the clouds at about 2500'.

I had about 21 gal of fuel on board for a flying weight of about 1,350#.

Home Airport: Arlington KAWO
Airport Altitude: 144'
OAT at 144': 67F
Aircraft: RV-7, CS Hartzell, IO-360 with LSE / Slick ign

Time to climb numbers below...

Alt........Time.....Climb Rate

144' 0:00
2000' 1:12 1547fpm
3000' 1:42 2000 fpm
4000' 2:11 2000 fpm
5000' 2:43 1935 fpm
6000' 3:22 1538 fpm
7000' 3:57 1714 fpm
8000' 4:34 1621 fpm
9000' 5:18 1363 fpm
10000' 6:04 1304 fpm

Average Climb rate was 1625 fpm from 144' to 10,000'. I lost just a little climb rate from 5000' to 6000' due to inattention to my airspeed. I tried to maintain exactly 100mph for the entire climb, but I let it drift up to 120mph momentarily.:rolleyes: I'm sure that I could have been under 6 minutes if I had maintained airspeed.

Maybe I'll figure out how to load my plane up to gross weight (1,800#) and try it again to see what numbers I get.

Man, I love these planes!:D
 
I gave it a try but couldn't quite match Scott's performance:
6:30 from 130' to 10K'.
6:56 from 130' to 10.5K'

I've never bothered to really figure out (with any precision) what airspeed gives the best climb in my RV-4. I'll experiment and post my best result someday.


TIME ALT AS OAT VS FTot RPM MAN FF
03:01:07 PM 140 6 28 -30 3.2 1840 23.7 2.2
03:01:31 PM 520 82 28 2670 3.3 2624 28.1 18.1
03:01:50 PM 1020 93 27 1590 3.4 2624 27.6 17.9
03:02:05 PM 1530 98 26 2010 3.5 2632 27.2 17.6
03:02:20 PM 2010 96 26 1880 3.6 2634 26.7 17.4
03:02:33 PM 2520 86 25 2380 3.6 2634 26.1 17.1
03:02:51 PM 3020 90 26 1890 3.7 2638 25.7 17.1
03:03:07 PM 3520 91 25 1970 3.8 2639 25.2 17.1
03:03:24 PM 4000 92 25 1650 3.9 2645 24.8 15.6
03:03:41 PM 4500 92 25 1820 3.9 2644 24.4 14.8
03:03:58 PM 5030 92 24 1980 4 2644 23.9 14.4
03:04:16 PM 5520 92 24 1460 4.1 2648 23.5 14.3
03:04:36 PM 6010 92 24 1400 4.1 2649 23.1 14.1
03:04:56 PM 6500 93 23 1390 4.2 2654 22.6 13.9
03:05:15 PM 7010 91 22 1630 4.3 2650 22.2 13.8
03:05:37 PM 7520 92 21 1500 4.4 2656 21.8 12.2
03:05:56 PM 8000 92 20 1520 4.4 2656 21.4 12.5
03:06:21 PM 8510 92 19 1290 4.5 2659 21 12.1
03:06:44 PM 9020 92 18 1380 4.6 2660 20.6 12.1
03:07:11 PM 9520 93 18 1170 4.7 2666 20.2 11.8
03:07:37 PM 10010 93 17 1040 4.8 2667 19.8 11.7
03:08:03 PM 10510 93 16 1140 4.9 2667 19.5 11.6

 
Last edited:
Kevin,

Is the OAT column in Celcius? If so, you were flying in 82*F compared to my 67*F. That would really cut into your performance.

What is the GPH column? I thought it was Gallons Per Hour, but the numbers don't make sense.

I'm betting that with the same engine/lighter plane, you could easily beat my numbers on a cooler day.

Nice flight!
 
DakotaHawk said:
Kevin,
Is the OAT column in Celcius? If so, you were flying in 82*F compared to my 67*F. That would really cut into your performance.
What is the GPH column? I thought it was Gallons Per Hour, but the numbers don't make sense.
I'm betting that with the same engine/lighter plane, you could easily beat my numbers on a cooler day.
Nice flight!
Click to expand...

Thanks for the soothing words, Scott. The fact is, though, that that you did better. No doubt I could improve my numbers with some tuning of my airplane and my flying but you could probably do the same.

Yes. My OAT reads in Celcius. So that explains some of it. Note that my governor limits me to 30-50 RPM shy of the 2700 RPM redline. What's not as obvious is that my induction system is dropping about 1" of manifold pressure at sea level. I'm running dual mags which is probably costing me significant power at higher altitudes. I started with about 29 gallons of fuel.

But until I fix those issues and post better numbers it all amounts to just making excuses. For now, you're the champ (for 4-cylinder RVs that is).

The "GPH" column is mislabeled as you correctly pointed out. It's actually the accumulated fuel usage.

Lighter? Maybe not. My empty weight is 1106#.
 
Kevin,

You and Scott have pretty well established that the CS prop does out perform the FP in climb.

Thanks for taking the time to have a shot at it.
 
I decided to give it another try since my engine has broken in better since the top overhaul and is giving me noticeably better performance. The temp was a little cooler and I started with about 17 fewer gallons of fuel. Other than that I flew it more-or-less the same as last time.

Result:
5:36 from 150' to 10150'. Average ROC: 1785 fpm.

2010_11_6_1000_climb.png
 
pierre smith said:
...my Air Tractor weighs 3800# empty and I've flown it at 8500#, on 680 SHP.

Do you jet jocks carry twice your empty weight?

Best,
Click to expand...

8500-3800=4700 load
8500/3800=2.23

so yes that is slightly more than twice your empty weight.


B-52

488,000-185,000=303,000 load
488,000/185,000=2.63

the answer to your question is yes.
 
Kevin Horton said:
Burt's later round-the-world design, the GlobalFlyer was even more impressive - 3,700 lb empty, 22,100 gross weight, for a ratio of 6.0:1.
Click to expand...

That would be 3,067 gallons at $4.50 per gallon (CA price as of 11/20/10) = $13,801.50 to top off the tanks. Maybe a little less, im sure it wasn't all fuel.
 
DakotaHawk said:
I had about 21 gal of fuel on board for a flying weight of about 1,350#.

Home Airport: Arlington KAWO
Airport Altitude: 144'
OAT at 144': 67F
Aircraft: RV-7, CS Hartzell, IO-360 with LSE / Slick ign

Time to climb numbers below...

Alt........Time.....Climb Rate

144' 0:00
2000' 1:12 1547fpm
3000' 1:42 2000 fpm
4000' 2:11 2000 fpm
5000' 2:43 1935 fpm
6000' 3:22 1538 fpm
7000' 3:57 1714 fpm
8000' 4:34 1621 fpm
9000' 5:18 1363 fpm
10000' 6:04 1304 fpm

Average Climb rate was 1625 fpm from 144' to 10,000'. I lost just a little climb rate from 5000' to 6000' due to inattention to my airspeed. I tried to maintain exactly 100mph for the entire climb, but I let it drift up to 120mph momentarily.:rolleyes: I'm sure that I could have been under 6 minutes if I had maintained airspeed.
Click to expand...
I made another attempt at the climb to 10,000'. My airplane and airport hasn't changed, but OAT was about 22F cooler.

Home Airport: Arlington KAWO
Airport Altitude: 144'
OAT at 144': 45F
Aircraft: RV-7, CS Hartzell, IO-360 with LSE / Slick ign

Time to climb numbers below...

Alt........Time.....Climb Rate

144' 0:00
1000' 0:44 1167 fpm
2000' 1:08 2860 fpm
3000' 1:35 2222 fpm
4000' 2:04 2069 fpm
5000' 2:34 2000 fpm
6000' 3:07 1818 fpm
7000' 3:39 1875 fpm
8000' 4:14 1714 fpm
9000' 4:50 1667 fpm
10000' 5:30 1500 fpm

This time I was able to peg the airspeed at exactly 100 - 105mph for the entire climb. I continuously leaned to maintain EGT at the same value throughout the climb. With the cooler OAT and the better speed control, I was able to chop 34 seconds off of my time to climb.

One of the things that I tried to do (but failed) was to get my Pitch AutoPilot to fly the climb. My thought was to set the Minimum Speed to 100mph, and set the Max Vertical Rate to 4000fpm, and set the desired altitude bug to 12,000ft. As soon as the A/P came live, I would engage it and let it fly the entire climb at exactly 100mph. It didn't work as planned - the A/P engaged as expected, but then it began a very slow process of increasing the climb rate while allowing the speed to go way over the desired 100mph! I ended up circling back to land, and then hand flying the climb.

Still having a blast flying my RV!:D
 
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