How Cool is this? Harrier Photos
06-07-2008, 01:55 AM
#26
RE: How Cool is this? Harrier Photos
Guys,
Just go back and read these threads...
http://www.rc-unionen.dk/nytforum/to...TOPIC_ID=12945
http://www.rcuniverse.com/forum/m_40...tm.htm#4019123
http://www.rcuniverse.com/forum/m_10...harrier/tm.htm
Just go back and read these threads...
http://www.rc-unionen.dk/nytforum/to...TOPIC_ID=12945
http://www.rcuniverse.com/forum/m_40...tm.htm#4019123
http://www.rcuniverse.com/forum/m_10...harrier/tm.htm
06-07-2008, 10:09 AM
#27
Join Date: Jun 2006
Location: ShulinCity, Taipei County, TAIWAN
Posts: 268
Likes: 0
Received 0 Likes
on
0 Posts
RE: How Cool is this? Harrier Photos
Hi all:
Here is a short video of Harrier's nozzle testing. The turbine is a JetCat P-180 and the ambient temperature is 32`C. Even in such hot weather, I still get 20Kgf of thrust in horizontal and vertical nozzle positions. In fact, with original exhaust cone, I can only get 19kgf thrust in the same ambient temperature.
http://video.google.com/videoplay?do...86407584145592
Here is a short video of Harrier's nozzle testing. The turbine is a JetCat P-180 and the ambient temperature is 32`C. Even in such hot weather, I still get 20Kgf of thrust in horizontal and vertical nozzle positions. In fact, with original exhaust cone, I can only get 19kgf thrust in the same ambient temperature.
http://video.google.com/videoplay?do...86407584145592
06-11-2008, 08:18 PM
#28
My Feedback: (41)
Join Date: Feb 2003
Location: HADLEY,
MA
Posts: 324
Likes: 0
Received 0 Likes
on
0 Posts
RE: How Cool is this? Harrier Photos
Just a stupid thought here, but could a turbo-prop set-up be used? How much thrust is available out of the exhaust nozzles, and then tap in to where the gearbox goes to the prop and utilize that for puffer nozzles or vice versa?? machine up a fan instead of a prop? Any thoughts guys??
06-11-2008, 08:29 PM
#29
RE: How Cool is this? Harrier Photos
Probably wouldn't work. The exhaust nozzle is optimised to drive the power turbine and produces only residual thrust, as most of its energy is used to drive the power turbine. Gearbox output speed is far too low to produce decent thrust with a fan. However, it might be possible to redesign the gearbox to produce the revs required for a reasonable fan rpm, then of course we would probably have enough thrust AND be dealing with cold air vectoring eliminating or at least reducing the heat problem of vectoring hot gas. Control puffer air could be from a compressor tapping (p3 ).
Just an idea, perhaps Wren are listening ! Someone will crack this.
Regards, David Gladwin.
Just an idea, perhaps Wren are listening ! Someone will crack this.
Regards, David Gladwin.
] Well someone will figure this out
06-11-2008, 08:47 PM
#31
Join Date: Jun 2006
Location: ShulinCity, Taipei County, TAIWAN
Posts: 268
Likes: 0
Received 0 Likes
on
0 Posts
RE: How Cool is this? Harrier Photos
ORIGINAL: Nighthawk117
Just a stupid thought here, but could a turbo-prop set-up be used? How much thrust is available out of the exhaust nozzles, and then tap in to where the gearbox goes to the prop and utilize that for puffer nozzles or vice versa?? machine up a fan instead of a prop? Any thoughts guys??
Just a stupid thought here, but could a turbo-prop set-up be used? How much thrust is available out of the exhaust nozzles, and then tap in to where the gearbox goes to the prop and utilize that for puffer nozzles or vice versa?? machine up a fan instead of a prop? Any thoughts guys??
The total thrust needed in this project is above 200N, a 160N core engined turbo-fan system maybe reasonable, but it is unavailable in market. So I use a P-180 turbine and move hot gas nozzles to CG position then left cold air nozzles just for dummy.
06-12-2008, 02:48 AM
#32
RE: How Cool is this? Harrier Photos
ORIGINAL: Likai
It is impossible to use current available turbo-prop in this project, cause the power needed to drive a fan which can generate about 120N is above 15HP shaft power and this is not include the power needed of hot gas thrust . The power of JetCat SPT-5 is about 10 HP and plus small unknown thrust from exhaust pipe.
The total thrust needed in this project is above 200N, a 160N core engined turbo-fan system maybe reasonable, but it is unavailable in market. So I use a P-180 turbine and move hot gas nozzles to CG position then left cold air nozzles just for dummy.
ORIGINAL: Nighthawk117
Just a stupid thought here, but could a turbo-prop set-up be used? How much thrust is available out of the exhaust nozzles, and then tap in to where the gearbox goes to the prop and utilize that for puffer nozzles or vice versa?? machine up a fan instead of a prop? Any thoughts guys??
Just a stupid thought here, but could a turbo-prop set-up be used? How much thrust is available out of the exhaust nozzles, and then tap in to where the gearbox goes to the prop and utilize that for puffer nozzles or vice versa?? machine up a fan instead of a prop? Any thoughts guys??
The total thrust needed in this project is above 200N, a 160N core engined turbo-fan system maybe reasonable, but it is unavailable in market. So I use a P-180 turbine and move hot gas nozzles to CG position then left cold air nozzles just for dummy.
if you are so close to CG i would go for 3 impellor fans imbedded in the wing, and a good gyro to control stability.
i seen a video years ago , with the same issue they used a few bruschless props on the wing tips just to stabilise it..
Great adventure.
ps i seen your thrust gain , but i am curious what is your temperature just after the turbine wheel doing?.
i have seen turbines coming apart.
if you squeeze it to much , the pressure will push back the lubrication from the aft bearing.
and causing faillure on the bearing?
06-12-2008, 04:45 AM
#33
Join Date: Jun 2006
Location: ShulinCity, Taipei County, TAIWAN
Posts: 268
Likes: 0
Received 0 Likes
on
0 Posts
RE: How Cool is this? Harrier Photos
ORIGINAL: digitech
if you are so close to CG i would go for 3 impellor fans imbedded in the wing, and a good gyro to control stability.
i seen a video years ago , with the same issue they used a few bruschless props on the wing tips just to stabilise it..
Great adventure.
ps i seen your thrust gain , but i am curious what is your temperature just after the turbine wheel doing?.
i have seen turbines coming apart.
if you squeeze it to much , the pressure will push back the lubrication from the aft bearing.
and causing faillure on the bearing?
ORIGINAL: Likai
It is impossible to use current available turbo-prop in this project, cause the power needed to drive a fan which can generate about 120N is above 15HP shaft power and this is not include the power needed of hot gas thrust . The power of JetCat SPT-5 is about 10 HP and plus small unknown thrust from exhaust pipe.
The total thrust needed in this project is above 200N, a 160N core engined turbo-fan system maybe reasonable, but it is unavailable in market. So I use a P-180 turbine and move hot gas nozzles to CG position then left cold air nozzles just for dummy.
ORIGINAL: Nighthawk117
Just a stupid thought here, but could a turbo-prop set-up be used? How much thrust is available out of the exhaust nozzles, and then tap in to where the gearbox goes to the prop and utilize that for puffer nozzles or vice versa?? machine up a fan instead of a prop? Any thoughts guys??
Just a stupid thought here, but could a turbo-prop set-up be used? How much thrust is available out of the exhaust nozzles, and then tap in to where the gearbox goes to the prop and utilize that for puffer nozzles or vice versa?? machine up a fan instead of a prop? Any thoughts guys??
The total thrust needed in this project is above 200N, a 160N core engined turbo-fan system maybe reasonable, but it is unavailable in market. So I use a P-180 turbine and move hot gas nozzles to CG position then left cold air nozzles just for dummy.
if you are so close to CG i would go for 3 impellor fans imbedded in the wing, and a good gyro to control stability.
i seen a video years ago , with the same issue they used a few bruschless props on the wing tips just to stabilise it..
Great adventure.
ps i seen your thrust gain , but i am curious what is your temperature just after the turbine wheel doing?.
i have seen turbines coming apart.
if you squeeze it to much , the pressure will push back the lubrication from the aft bearing.
and causing faillure on the bearing?
The EGT in this video is 700 degrees, only about 20 degree higher than original nozzle.
06-13-2008, 01:29 AM
#35
Banned
Join Date: Jul 2004
Location: England, , UNITED KINGDOM
Posts: 2,725
Likes: 0
Received 1 Like
on
1 Post
RE: How Cool is this? Harrier Photos
I thought the real Harrier used gallons of water injected into the exhaust to control heat..... I was also told that the hover time was limited by the amount of water the plane could carry
Dennis
Dennis
06-13-2008, 12:09 PM
#37
RE: How Cool is this? Harrier Photos
ORIGINAL: bigplumbs
I thought the real Harrier used gallons of water injected into the exhaust to control heat..... I was also told that the hover time was limited by the amount of water the plane could carry
Dennis
I thought the real Harrier used gallons of water injected into the exhaust to control heat..... I was also told that the hover time was limited by the amount of water the plane could carry
Dennis
08-29-2008, 10:42 PM
#38
Member
My Feedback: (7)
Join Date: Nov 2002
Location: Palmdale,
CA
Posts: 54
Likes: 0
Received 0 Likes
on
0 Posts
RE: How Cool is this? Harrier Photos
Gents,
You're both right. The water injection system on the AV-8B allows the engine to produce greater thrust by cooling the turbine. The 408 (pegasus) will produce the "wet" datum thrust without water, however it will most likely result in the engine needing to be replaced due to overtemp.
I am very excited to see a dedicated effort to produce a viable RC AV-8. Ive just recently crossed over to the dark side of turbine models after years of not having an adequate field (and turbine waiver holders) locally to make it worthwhile. So maybe I will be able to get an AV-8 as my first scale jet.
As a side note, I know everyone wants to have it hover, but I would love to see one that could do predictable STOL (Short T/O or Landing) ops. That is the most prevelant mode of T/O or landing in the AV-8B for myriad reasons. Watching a turbne model that big "jump" off the runway after a short roll (50') would be very impressive in itself.
Best of luck to Skymaster, keep up the good work.
You're both right. The water injection system on the AV-8B allows the engine to produce greater thrust by cooling the turbine. The 408 (pegasus) will produce the "wet" datum thrust without water, however it will most likely result in the engine needing to be replaced due to overtemp.
I am very excited to see a dedicated effort to produce a viable RC AV-8. Ive just recently crossed over to the dark side of turbine models after years of not having an adequate field (and turbine waiver holders) locally to make it worthwhile. So maybe I will be able to get an AV-8 as my first scale jet.
As a side note, I know everyone wants to have it hover, but I would love to see one that could do predictable STOL (Short T/O or Landing) ops. That is the most prevelant mode of T/O or landing in the AV-8B for myriad reasons. Watching a turbne model that big "jump" off the runway after a short roll (50') would be very impressive in itself.
Best of luck to Skymaster, keep up the good work.
