Has anyone suggestion for high altitude turbocharger
 (40000feet-12000m) for renesis (75% of maximum power)?

 Garrett?
 http://www.turbobygarrett.com/turbobygarrett/products/turbochargers.html

 B.r.

 Viktor

 All,

 Perhaps this was discussed before, but I 'discovered' a
 fabulous
 book on the rotary engine: Street Rotary by Mark
 Warner, and his
 equally fabulous book: Street Turbocharging. Warner is the real
 deal: "Mark Warner is a professionally licensed
 mechanical
 engineer, a member of the Society of Automotive Engineers,
 and
 an expert in the fields of turbochargers and forced
 induction. He
 has over 25 years of machine design and fabrication
 experience,
 ranging from complex aerospace systems to high-performance
 automotive applications. He is the author of numerous
 patents and
 has published dozens of articles for the automotive press,
 including
 technical, how-to, and feature pieces."
 But the best thing about his books is that he tells you the
 numbers
 you need to know about the rotary and [in both books]
 about
 turbocharging...
 the important stuff without getting too lost in extraneous
 nonsense.
 His books
 are WELL illustrated, simple to understand, and he always
 supplies you
 with relevant numbers such as typical operating temperature
 ranges and
 pressures for oil, coolant, boost, etc etc.

 I carefully read the first book, took careful notes, and I
 feel I can
 much more confidently follow the conversations after having
 done so!!

 In fact, I have an extra "Street Turbocharging" book by
 Warner I can
 send someone for free if they desire.

 Gene Kahn


 Gene

 I would like to take you up on that generous offer. Will cover USPS
 media mail costs with Paypal.

 regards Robert




I just ordered one.
 Mark LaPierre

--


Does the book explain calculation corrections caused by drop in
inlet density and pressure with altitude?

Calculations by Garrett are logical, but they are for cars - do not
include altitude calculations. With altitude one has almost same
mass flow but much higher volume flow and different blade relative
angles. So the turbocharger increases by size for the same mass flow.

Doug, five years ago I was in Himalaya (trip from Lassa to Mount
Everest base camp 3800m-5600m). One can find there cold (no wood no
heating at all), "thin" air but still strong wind, extreme low
humidity, dust, uneatable "zampa" and useful yak tea. Maybe there
are bees but I didn't find them.

Viktor

Here are a couple of spread sheets that might help.
js was done by a gentleman that achieved 50,000 feet with a sequential
turbo 914 although the spread does not reflect that.

Paul Lamar


Viktor, Paul and all,

If I interpret Viktor's question correctly...no, the book does not
explain calculation
corrections caused by drop in inlet pressure and density with
altitude. It just
shows compressor maps, and explains them very well. It does
explain things like the "choke zone" [such as when the compressor
is too small for the application] and wheel speeds will increase
while compressor efficiency declines dramatically...and it also
explains compressor surge, when the compressor is too large
for the application, which can also cause turbo failure from
bearing failure. However, compressor maps are based on
pressure ratio vs corrected air flow, usually at 85 degrees F.
To the extent that inlet pressure and corrected air flow
are affected by altitude [and varying temperatures] this could
affect the map.

And now I will speculate on Viktor's question in case others might be
wondering the same thing, and also so that I can be corrected
by Paul and others: I am guessing that a high density altitude might
mimic a compressor too small for the job and lead to a "choke zone"
but trying to compensate for such a situation by using a larger
compressor might lead to surge at lower altitudes. Just have to have
a waste gate unless we use aerocharger adjustable vanes.

OK everybody, rip me to shreds.

Gene Kahn

Exactly! Ones density and ambient pressure is significantly
changed (cca 0.3 Rho_o) charger characteristics differ drastically.

B.r.

Viktor

Gene,

Sort of.  Also there is a world of difference if you are depending on say 15psi of boost at sealevel or simply want to normalize the engine at 16,000.  Hugh MacInnes explains it well in his book on Turbochargers.   p.104

"Temperature Effect at Altitude:  Depending on the engine and the amount of supercharging at sea-level, the engine should be able produce sea-level power up to at least 16,000 feet.  Even if the boost pressure is 15 psig at sea-level, the lower temperatures at high altitudes will help compensate for the "thinner" air."

p.105  "As air-inlet temperature goes down, a centrifugal compressor produces the same pressure ratio at a lower speed.
The exact ratio is the square root of  Standard Temperature Absolute over inlet Temperature Absolute."

Are you talking about a 55% cruize or a 85% cruise. Power settings also effect turbo performance.  What's your mission profile?


Doug in Japan