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Experimental Ducted Fan Aircraft Designs

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henryk

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way they can fit a larger cooler is to insert
=one,but bigger and located as "lays it down backwards"

(as we see on the photo).
BTW=+ INTERCOOLER=
" In the plane of symmetry, it was also necessary to create a NACA inlet for the air supply to the power unit intercooler. "

BUT= moore power (230/190 HP=+12 %) and 18% greater FAN diameter against weight increase ! (600/450=33 % !)

a=Fthrust/m !!!
 

Doggzilla

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I do not understand.

Are you saying that they have already added a laying down radiator?

Do you have a link to show new improvements?
 

Blackhawk

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Nearly all modern 4 stroke jet ski engines use "Closed Loop" cooling systems (not open loop as they previously did); they use a heat exchange which does the same job as a normal radiator and operate to a maximum engine temperature of around 195F

There would be no problem working out what size radiator you would need.

Most Radiator specialists would be able to work the size out for you.
 

Blackhawk

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From the Rotax Site.

Rotax 4-TEC 1503 XHO

Closed-Loop Cooling System
..........
Uses coolant to keep the engine running at the ideal temperature,
much like a car’s radiator. Also keeps out corrosive saltwater and debris
 

Malish

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This is the exploded view of the Rotax Jet Ski 4-Tech engine.

Heat exchange unit indicated
What is the weight of this engine? Wrong to assume that this heat exchanger will work in aircraft as air radiator(or with air radiator) - is NO COLD water supply there! Simply replace heat exchanger with air radiator may not work there.
And again - more powerful engine need larger radiator, but there is no "room" for it in this aircraft.
 

Vigilant1

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Liquid-to-liquid heat exchangers can be compact and very efficient. It takes a lot more room and tubing to get the same amount of effectiveness with liquid-to-gas exchangers ("radiators").

Do we know the design temperature of the engine coolant in the Rotax Jet Ski when it returns to the engine, and the rate (l/m, etc) at which the coolant is being pumped?
 

Malish

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It would be unwise to remove or bypass the Heat exchange; just connect the two hoses from the heat exchanger to a radiator with an additional water pump
Then it will add more weight and complexity. Plus, to get right coolant temperature(25 deg.C) it's will be require even larger radiator(heat exchanger use cold outboard water). This power plant setup will became very heavy, complex and unreliable for aircraft use.
 

Blackhawk

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Malish,

With your GM LS6 V8; what are your temperatures indicating for:

1 Idle
2 Take-off
3 Cruise
 

Malish

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With your GM LS6 V8; what are your temperatures indicating for:

1 Idle
2 Take-off
3 Cruise
LS6 designed working coolant temperature is 105 deg.C(pressurized system)
We use waterless Evans coolant(no pressurization and 185 deg.C boiling point) and 90 deg.C thermostat.
At Idle we have - 85-90 deg.C
At Cruise and Take-off - 100+ deg.C
On future aircraft we're planing to install larger radiator because this one was designed for regular antifreeze which have better(then waterless) heat exchange ratio. Also we're making airflow over radiator going upwards(instead of downwards) to improve TO and Cruise cooling.

PC202084.JPG PC202085.JPG PC202086.JPG
 
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henryk

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They are talking about small jet engine
="сила есть ("suitable jet engine with thrust about 3000 N. "),ума не надо !"
=и "на полный желудок и дурак заснёт."
 
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Doggzilla

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As Malish has pointed out, the heatsink will not work properly.

It’s designed to use cold water in the open loop. It’s not sized right to use warm water. It’s too small to cool the closed loop if the open loop is using warm rad water.

It should be removed or bypassed and use a direct loop from the radiator.
 
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