I wasn't thinking very clearly last night, it's pretty obvious
that 175 / 6 is about 30 mpg. (29.2)
If you are getting 0.47 lb/hr/HP, 6gph would work out to 76.6 HP,
sounds reasonable at that altitude.
What do you think your actual BSFC is under these conditions?
If your mixture is about 17:1 lean and mine is 12:1 rich, that would
correlate well with 29 vs 21 mpg.
Perry
Tracy wrote:
Yes, my head (and main scale of ASI) is still calibrated in miles per
hour.
Yep, if you slowed down and were able to lean the mixture, your
canard should do better MPG than my RV.
----- Original Message -----
Sent: Tuesday, May 23, 2006 12:56 AM
Subject: [FlyRotary] Re: 100LL plug fouling / MPG
Tracy, just so we are on the same page, I assume you mean 175
MPH (not knots)?
My data was taken between 10,500 and 12,500. It might be
interesting to see what my fuel burn and MPG would be if I slowed it
down to 175 MPH.
Tracy wrote:
About 30 mpg is what I currently see under best case conditions
(12,500 - 14,500 MSL, 6.0 gph, 175 TAS).
Interesting experiment on way back from Lumberton. 4 RVs
departed for Florida Sunday AM, 3 Lyc powered and my rotary. The Lyc
guys were taking too long to get packed up (I get antsy when I'm ready
to go) so I left 15 minutes before they did and told them I would go
slow and meet up on the way since we were flying the same flight plan.
The Lyc guys flew at 8.5 GPH power setting and I flew at 6.0 GPH. Had
head winds all the way but interesting part was that after 2.75 hr and
370 miles after my takeoff, the Lycs caught up to me. The extra speed
of those 2.5 GPH really does not buy much! And I got to spend more
time in my beloved airplane : )
Fun & Relaxing trip & fly-in BTW.
Tracy (must get Ed's Gin & tonic formula)
Sent: Monday, May 22, 2006 12:33 PM
Subject: [FlyRotary] 100LL plug fouling
Al Wick might have got some of his "100LL in rotary" comments
from my experience.
I can't burn 100LL, it will foul my leading spark plugs after
only 4 hours. That is because my engine runs rich-best power all the
time. Of course running rich results in a higher fuel burn too. These
days I'm doing about 160 knots on 8.8gph, or 184 mph @ 21 mpg.
Burning mogas all the time, my leading spark plugs still only
last about 50 to 60 hours. Trailings always look better.
My 1988 RX-7 with exactly the same engine gets about 18.5 mpg
combined city/hwy driving, probably low 20s if it was continuous
freeway.
If I had lean control I would expect results more like Ed
Anderson with regard to 100LL and plug fouling.
I would like to see some fliers express fuel usage in mpg, an
easy way to compare efficiencies. For example, Tracy and Ed leaning
might see 25 to 30 mpg?