Today's Message Index:
----------------------
1. 10:07 AM - First high speed taxi (Larry McFarland)
2. 03:10 PM - Re: First high speed taxi, OV (gary)
3. 04:30 PM - Re: First high speed taxi, OV (Larry McFarland)
4. 07:03 PM - Re: First high speed taxi, OV (The Meiste's)
Message 1
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| Subject: | First high speed taxi |
pts rule name description
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--> Stratus-List message posted by: "Larry McFarland" <larrymc@qconline.com>
Hi guys,
It's getting close here, but I wanted to share this experience.
Less than flight, but you get the feeling..........
First High Speed Taxi
June 22 It's sunny and winds are 6 to 13 north-northwest. This is a good day to
do a hi-speed taxi. I'm feeling like the student pilot on a first solo, but
pushed the feeling aside. I'd made notes of things to focus on for doing this
first one. They all relate to cooling and control responses. Clearance Delivery
was informed that Experimental N601EZ requested a full runway taxi with a
180 back to the other end at high-speed with no airtime. I waited approximately
15 minutes for ground control to clear me to the runway from the hangars,
so I pointed the plane's radiator into the breeze and waited. The RPMs were kept
down and temps never exceeded 219 CHT and 1100 EGT. Ground control provided
4500-feet of runway on 5-26, which is a direct crosswind in very low wind conditions.
The EIS was set for 230 EGT and 1400 CHT. Acceleration on clearance
to the runway was very quick and I came off the throttle to keep all three down
and pulled the stick back to feel the nose get very light. I crossed 9-27
and rolled to the end and turned around to do a repeat. The throttle was raised
again but held and the plane bounced lightly about a foot in the air while
crossing 9-27. This doesn't count as flight! The lightly loaded rear wheels
slid left a little, like being on grease, but that was the crosswind response
to the cushion of air. There was no directional instability. Quite the contrary!
The nose wheel lifted easily I found I could keep it there taxiing at about
35 mph to the other end. The 2 EGT temps were within 20 degrees of each other
and EGT on high taxi approached but never reached 1200-degrees F. Coolant
topped out at 189-degrees F.
All my concern for temps is based on the Stratus-Ram engine and my radiator setup
which is a subset of P51 scoop and louvers etc.
So far, so good.
Really looking forward to the next taxi and eventual flight.
Larry McFarland 601HDS @ www.macsmachine.com
Message 2
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| Subject: | Re: First high speed taxi, OV |
--> Stratus-List message posted by: "gary" <FlyinK@Efortress.com>
Excellent Larry! I was waiting to hear how that radiator scoop works out.
Sounds like a very high speed taxi test if the wheels hopped up, much more
daring than I was. Sounds like it's ready - good luck and be careful! What
was the OAT? Ground cooling is good?
70 hours and loving my plane and engine. Flew with the doors off last week
and subsequently just got my new ANR headset in today. I found out how
noisy it can be, but worth it. Can it get any more fun? Oh ya, floats
someday ;<}
My alternator OV contactor failed. I noticed lack of charging voltage when
doing a local flight. Bypassed the OV for now, not sure if all the extra
"safety" stuff is worth it. My fault though, I mounted it on the cyl head
without isolation from heat or vibration. I kinda figured it wouldn't last
long there. I added overcurrent (fuse) too. All are extra weight, money,
work and connections. Same w/fuel pressure, flow, coolant press, etc.
Simple is probably better with this simple engine.
Gary Krysztopik
Pelican N522GK
Newport, R.I.
----- Original Message -----
From: "Larry McFarland" <larrymc@qconline.com>
Subject: Stratus-List: First high speed taxi
> --> Stratus-List message posted by: "Larry McFarland"
<larrymc@qconline.com>
>
> Hi guys,
> It's getting close here, but I wanted to share this experience.
> Less than flight, but you get the feeling..........
> First High Speed Taxi
>
> June 22 It's sunny and winds are 6 to 13 north-northwest. This is a good
day to do a hi-speed taxi. I'm feeling like the student pilot on a first
solo, but pushed the feeling aside. I'd made notes of things to focus on
for doing this first one. They all relate to cooling and control responses.
Clearance Delivery was informed that Experimental N601EZ requested a full
runway taxi with a 180 back to the other end at high-speed with no airtime.
I waited approximately 15 minutes for ground control to clear me to the
runway from the hangars, so I pointed the plane's radiator into the breeze
and waited. The RPMs were kept down and temps never exceeded 219 CHT and
1100 EGT. Ground control provided 4500-feet of runway on 5-26, which is a
direct crosswind in very low wind conditions. The EIS was set for 230 EGT
and 1400 CHT. Acceleration on clearance to the runway was very quick and I
came off the throttle to keep all three down and pulled the stick back to
feel the nose get v!
> ery light. I crossed 9-27 and rolled to the end and turned around to do a
repeat. The throttle was raised again but held and the plane bounced
lightly about a foot in the air while crossing 9-27. This doesn't count as
flight! The lightly loaded rear wheels slid left a little, like being on
grease, but that was the crosswind response to the cushion of air. There was
no directional instability. Quite the contrary! The nose wheel lifted
easily I found I could keep it there taxiing at about 35 mph to the other
end. The 2 EGT temps were within 20 degrees of each other and EGT on high
taxi approached but never reached 1200-degrees F. Coolant topped out at
189-degrees F.
>
> All my concern for temps is based on the Stratus-Ram engine and my
radiator setup
>
> which is a subset of P51 scoop and louvers etc.
>
> So far, so good.
>
> Really looking forward to the next taxi and eventual flight.
>
>
> Larry McFarland 601HDS @ www.macsmachine.com
>
>
Message 3
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| Subject: | Re: First high speed taxi, OV |
--> Stratus-List message posted by: "Larry McFarland" <larrymc@qconline.com>
Subject: Re: Stratus-List: First high speed taxi, OV
> --> Stratus-List message posted by: "gary" <FlyinK@Efortress.com>
>
> Excellent Larry! I was waiting to hear how that radiator scoop works out.
> Sounds like a very high speed taxi test if the wheels hopped up, much more
> daring than I was. Sounds like it's ready - good luck and be careful!
What
> was the OAT? Ground cooling is good?
Gary,
Todays outside air temperature was 74-degrees F. It appears the P51radiator
intake and exhaust louvers do improve the heat exchange for the ground run,
short burst of high rpm and the long wait prior to taxi. I was surprised
that engine temps actually level off and dropped a couple of degrees when
the engine is facing into the breeze and idling at 1100 rpm. The real test
will come when the plane gets on the 90-270, 10,000-ft runway at higher
rpms. The more rpm, the more cooling needed to put heat behind the plane. I
just hope they keep pace. When regular flight commences, I'm going to
record the EGT, CHT, coolant, oil temps and airspeeds in 100-rpm increments
from 3800, to 4800 for 5-minutes each to see how it graphs out. Then
perhaps Kelly in his 601 Stratus HD will be able to provide matching
information and we might learn a bit more about these radiator
configurations that cool the Stratus Subaru.
Larry McFarland - 601HDS
Oops, I inadverdently transposed letters in the previous write up "CHT" and
"EGT" for presets on the EIS system. Brain disconnected from the fingers
while typing.
Message 4
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| Subject: | Re: First high speed taxi, OV |
--> Stratus-List message posted by: "The Meiste's" <meiste@essex1.com>
> Todays outside air temperature was 74-degrees F. It appears the
P51radiator
> intake and exhaust louvers do improve the heat exchange for the ground
run,
Then
> perhaps Kelly in his 601 Stratus HD will be able to provide matching
> information and we might learn a bit more about these radiator
> configurations that cool the Stratus Subaru.
++++++++++++++++++++++++++++++++++++++++++++++++++++
Hi Larry,
Glad to help out any time. For you guys on the list that may not no I'm
located approx 50 mile from Larry. I departed SQI this afternoon with an OAT
of 77 deg & 68 at my flight alt. My cruising speed today was 4,200 RPM (more
RPM than my normal cruse but it was a relatively cool day here in the
mid-west). My stock ZAC installation was running 195 on water & 225 on oil.
Larry the numbers below are the figures I had stuck on my IP the day you
flew my plane. They are my normal temps at these RPM settings & flight alt
temps, possibly they can be a ref for your P51 set-up.
Kelly
601 HD Stratus (88 hours)
OAT @ Alt ----- Cruise RPM ----- Water ----- Oil
80 - 85 ------------- 3,800 ---------- 200 ------ 225
75 - 80 --------------3,900 ---------- 195 ------ 225
70 - 75 ------------- 4,000 ---------- 195 ------- 220
65 - 70 ------------- 4,100 ---------- 190 ------- 220
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