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turbo prop aerobatic plane (it flies!!!!!) - 7/30/2003 3:08:53 PM   
robert


 

Posts: 2443
Joined: 3/2/2002
From: private, IRELAND
Status: offline 		[QUOTE]Originally posted by edible_engine
so the enguine is making high power and you just controll the pitch
[/QUOTE]
That would make hovering alot easier IMO?

If the prop was stalling at full throttle, the plane would loose speed and crash.

(in reply to mec)
       Post #: 326

turbo prop aerobatic plane (it flies!!!!!) - 7/30/2003 3:28:12 PM   
digitech


 

Posts: 1705
Joined: 8/23/2004
From: klimmenlimburg, NETHERLANDS
Status: offline 		[QUOTE]Originally posted by robert
That would make hovering alot easier IMO?

If the prop was stalling at full throttle, the plane would loose speed and crash. [/QUOTE]

ok ok here is a puzzle

with a 22x12 we can hover and go up and do a knife edge
with a 26x8 we can hover go up and CANT do a knife edge

_____________________________

Sandor Kruise
Dealers for:JetCat,Graupner,Futaba,Fei-Bao,Pro-Lynx,Airpower,Jets-munt,Xicoy.
"Home of the Jet-1A Gears"

(in reply to mec)
       Post #: 327

prop speed - 7/30/2003 3:43:33 PM   
blue62



Posts: 316
Joined: 7/3/2003
From: Rogers , TX,
Status: offline 		i got this from the windsor propellor website (masterairscrew) maybe this will help with the propellor speed thing. just a thought

For model airplane purposes, the best tip speed for efficiency and noise requirements is 600 feet per second. This is due to compressibility losses and the fact that subsonic airfoils do not work well in transonic/sonic speeds with required sound levels.
Feet Per Second (ft/s) = RPM x diameter in inches x .00436
For example, to find the tip speed of a 10x6 on a .40 size engine running at 13,500 RPM, the equation would be 13,500 x 10 x .00436 = 588.6 ft/s.

To find the correct diameter at 600 ft/s, use this formula:
Diameter in inches = 138,000 / RPM
Using a .40 engine running at 13,500 RPM, the equation would read as follows:

138,000/13,500 = 10.22

Rounding down, the correct diameter is 10"

For both of the above formulas, use RPM for the optimum power band of your engine. Consult your owner's manual if you do not know this number.


john

(in reply to mec)
       Post #: 328

Re: prop speed - 7/30/2003 3:57:28 PM   
digitech


 

Posts: 1705
Joined: 8/23/2004
From: klimmenlimburg, NETHERLANDS
Status: offline 		[QUOTE]Originally posted by blue62
i got this from the windsor propellor website (masterairscrew) maybe this will help with the propellor speed thing. just a thought

For model airplane purposes, the best tip speed for efficiency and noise requirements is 600 feet per second. This is due to compressibility losses and the fact that subsonic airfoils do not work well in transonic/sonic speeds with required sound levels.
Feet Per Second (ft/s) = RPM x diameter in inches x .00436
For example, to find the tip speed of a 10x6 on a .40 size engine running at 13,500 RPM, the equation would be 13,500 x 10 x .00436 = 588.6 ft/s.

To find the correct diameter at 600 ft/s, use this formula:
Diameter in inches = 138,000 / RPM
Using a .40 engine running at 13,500 RPM, the equation would read as follows:

138,000/13,500 = 10.22

Rounding down, the correct diameter is 10"

For both of the above formulas, use RPM for the optimum power band of your engine. Consult your owner's manual if you do not know this number.


john [/QUOTE]


nice formula

but since the turboprop we use (Wren) has no limit on the speed
you cant use this formula

our formula is: buy lots of props mount them and see wich one performs best
all is also dependant on weather , model ,weight,etc

_____________________________

Sandor Kruise
Dealers for:JetCat,Graupner,Futaba,Fei-Bao,Pro-Lynx,Airpower,Jets-munt,Xicoy.
"Home of the Jet-1A Gears"

(in reply to mec)
       Post #: 329

turbo prop aerobatic plane (it flies!!!!!) - 7/30/2003 4:05:31 PM   
robert


 

Posts: 2443
Joined: 3/2/2002
From: private, IRELAND
Status: offline 		Maybe the decreased pitch means less airspeed and propwash speed over the rudder?

(in reply to mec)
       Post #: 330

turbo prop aerobatic plane (it flies!!!!!) - 7/30/2003 4:18:02 PM   
blue62



Posts: 316
Joined: 7/3/2003
From: Rogers , TX,
Status: offline 		This is due to compressibility losses and the fact that subsonic airfoils do not work well in transonic/sonic speeds with required sound levels.
Feet Per Second (ft/s) = RPM x diameter in inches x .00436
For example, to find the tip speed of a 10x6 on a .40 size engine running at 13,500 RPM, the equation would be 13,500 x 10 x .00436 = 588.6 ft/s.

no matter how fast u turn the engine this still applies i think

the propellor is still limited to subsonic speeds. i believe this also applies tto full size props. maybe someone with propellor science experience can enlighten me further

john

(in reply to mec)
       Post #: 331

turbo prop aerobatic plane (it flies!!!!!) - 7/30/2003 4:22:25 PM   
digitech


 

Posts: 1705
Joined: 8/23/2004
From: klimmenlimburg, NETHERLANDS
Status: offline 		[QUOTE]Originally posted by blue62
This is due to compressibility losses and the fact that subsonic airfoils do not work well in transonic/sonic speeds with required sound levels.
Feet Per Second (ft/s) = RPM x diameter in inches x .00436
For example, to find the tip speed of a 10x6 on a .40 size engine running at 13,500 RPM, the equation would be 13,500 x 10 x .00436 = 588.6 ft/s.

no matter how fast u turn the engine this still applies i think

the propellor is still limited to subsonic speeds. i believe this also applies tto full size props. maybe someone with propellor science experience can enlighten me further

john [/QUOTE]

all theoretic aside: a big prop with small pitch makes a awesome sound when it does a slow pass

_____________________________

Sandor Kruise
Dealers for:JetCat,Graupner,Futaba,Fei-Bao,Pro-Lynx,Airpower,Jets-munt,Xicoy.
"Home of the Jet-1A Gears"

(in reply to mec)
       Post #: 332

turbo prop aerobatic plane (it flies!!!!!) - 7/30/2003 4:26:51 PM   
blue62



Posts: 316
Joined: 7/3/2003
From: Rogers , TX,
Status: offline 		can't argue with that

just wondering how efficient it is!!

lol just tryin to do my part

john

(in reply to mec)
       Post #: 333

Awsome noise - 7/31/2003 12:18:28 PM   
turboraven



Posts: 14
Joined: 10/26/2002
From: Norfolk England
Status: offline 		[QUOTE]Originally posted by Sandor
all theoretic aside: a big prop with small pitch makes a awesome sound when it does a slow pass [/QUOTE]
followed shortly after by expensive shower of power turbine blades, complaints from non flying residents and loss of flying field....!!

(in reply to mec)
       Post #: 334

turbo prop aerobatic plane (it flies!!!!!) - 8/1/2003 4:44:06 PM   
learjet-RCU



Posts: 243
Joined: 4/29/2002
From: Marco Island, FL, USA
Status: offline 		with the assistance of mec over one year testing and planning now it's possible to start the next project with a PJW turbine.

TUCANO


[URL=http://www.jets.at/images/gallery/tucano/index.html]see the gallery for more pic's[/URL]

[URL=http://www.jets.at]or here[/URL]


_____________________________

Michael Binder www.jetpower-usa.com
The most advanced online hobby business solution.

(in reply to mec)
       Post #: 335

turbo prop aerobatic plane (it flies!!!!!) - 8/1/2003 6:03:10 PM   
art43



Posts: 130
Joined: 10/17/2002
From: Redding, CA, USA
Status: offline 		Just found this thread tonight,and had to read it all from page 1. Mec,you made it read like a great who-done it novel. The best reading i've done in a long time.Hope there are more chapters to come.Congratulation on a well thought out project. art43


_____________________________

art43 Professor of Bovine Scatology

(in reply to mec)
       Post #: 336

turbo prop aerobatic plane (it flies!!!!!) - 8/3/2003 11:27:51 AM   
DSA.308



Posts: 1493
Joined: 10/27/2002
From: Denver, CO, USA
Status: offline 		Mec, now thats what I call thinking WAY outside the box! After seeing this I have no doubt anything is possible in RC, given enough determination, knowledge, and ability. Ever seen the(helicopter) Turbine powered superbike(motorcycle)? I thought that was cool until I saw your turboprop R/C plane Mec! I read from page 1 to the finish, thats the best project RC ANYTHING, I've ever seen!

_____________________________

"You are going into handcuffs for your OWN safety!"

(in reply to mec)
       Post #: 337

turbo prop aerobatic plane (it flies!!!!!) - 8/4/2003 1:27:20 PM   
digitech


 

Posts: 1705
Joined: 8/23/2004
From: klimmenlimburg, NETHERLANDS
Status: offline 		[QUOTE]Originally posted by learjet
with the assistance of mec over one year testing and planning now it's possible to start the next project with a PJW turbine.

TUCANO


[URL=http://www.jets.at/images/gallery/tucano/index.html]see the gallery for more pic's[/URL]

[URL=http://www.jets.at]or here[/URL] [/QUOTE]

yes michael very nice

remember i called you for some pictures of the tucano
however you did not have any until i see now that you do have some
if you have any more please send them to [email]sandor@digitech.nl[/email]
as i was planning to buy a tucano
but for me to drive up to austria i need to see some more details of the tucano

reg Sandor

_____________________________

Sandor Kruise
Dealers for:JetCat,Graupner,Futaba,Fei-Bao,Pro-Lynx,Airpower,Jets-munt,Xicoy.
"Home of the Jet-1A Gears"

(in reply to mec)
       Post #: 338

turbo prop aerobatic plane (it flies!!!!!) - 8/4/2003 1:58:20 PM   
learjet-RCU



Posts: 243
Joined: 4/29/2002
From: Marco Island, FL, USA
Status: offline 		[QUOTE]remember i called you for some pictures of the tucano [/QUOTE]

Hello Sandor,

sorry i was waiting for your inquiries by mail, i did not know your e-mail adress.


_____________________________

Michael Binder www.jetpower-usa.com
The most advanced online hobby business solution.

(in reply to mec)