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Performance with and without pants and fairings

A

ao.frog

Well Known Member
Hi.

I've just installed the pants and farings and found that they gave 11-18 KIAS speed increase.
Wheelpants alone gave 5-9 KIAS speed increase.

Here are the data I found:


1000'
21?/2100 RPM: 122 KIAS / 133 KIAS / FF 30
22?/2200 RPM: 128 KIAS / 141 KIAS / FF 33
23?/2300 RPM: 135 KIAS / 148 KIAS / FF 36
24?/2400 RPM: 138 KIAS / 154 KIAS / FF 40
25?/2500 RPM: 144 KIAS / 158 KIAS / FF 46
Full thr/2700 RPM: 158 KIAS / 172 KIAS /


3000'
21?/2100 RPM: 122 KIAS / 134 KIAS
22?/2200 RPM: 128 KIAS / 142 KIAS
23?/2300 RPM: 135 KIAS / 150 KIAS
24?/2400 RPM: 142 KIAS / 154 KIAS
25?/2500 RPM 145 KIAS / 161 KIAS
Full thr/2700 RPM: 154 KIAS / 170 KIAS


6000?
21?/2100 RPM: 125 KIAS / 136 KIAS
22?/2200 RPM: 128 KIAS / 143 KIAS
23?/2300 RPM: 135 KIAS / 151 KIAS
24?/2400 RPM: 142 KIAS / 157 KIAS
24?/2500 RPM: 144 KIAS / 161 KIAS
24?/2700 RPM: 146 KIAS / 164 KIAS

9000?:
21?/2100 RPM: 125 KIAS / 139 KIAS
21?/2200 RPM: 131 KIAS / 148 KIAS
21?/2300 RPM: 133 KIAS / 151 KIAS
21?/2400 RPM: 134 KIAS / 153 KIAS
21?/2500 RPM: 135 KIAS / 155 KIAS
21?/2700 RPM: 137 KIAS / 157 KIAS

Rmk: Bold numbers are full throttle at the given altitude.

FF is liters per hour, leaned to 75* ROP

I haven't calibrated the airspeed indicator 100% yet, but it seems to me it's within 5 KIAS .
Besides; it's the difference in performance I want to show here, not the exact speeds.
 
An addition

Hi again.

An addition to my post above:

Today I tried the "B-curve" on the P-mags for the first time and leaned to 50* LOP without problems.
It seems to me that the engine was more happy at 50*LOP with the B-curve than the A-curve. At 50*LOP with the A-curve, the engine ran slightly rough.

For those of unfamilar with P-mags: the A-curve of their variable timing gives max 34* advance.
The B-curve gives max 39* advance.

I didn't try all the settings as before, but did two of them just to get an idea:

2100/21: 24 litre/hr
2400/24: 32 litre/hr

In other words: it looks like flying at 50* LOP instead of 75*ROP saves close to 20% fuel...

Not bad at all...
 
nice

Thanks for sharing Mr. Frog...

That's a great increase. Any thoughts on where you're at relative to Van's numbers?

So, how does having a flying -7 effect your progress and decision-making on the second one you're building? OOC, do you have a top list of things you wanted to do differently?

Thanks,

Don.
 
WOW

I put the pants and fairing on yesterday and went for the test flight today.
Last time (w/o pants and fairings) I has a TAS of 174 MPH @ 2450rpm 23" map and 10.5 GPH. Today, I got 201 MPH with the exact same settings. Both flights were at 8000' but on todays flight I did not have a 200lb copilot with me. I am very impressed!!!
 
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