Boomerang nano thrust line problem?
08-19-2012, 10:48 AM
#1
Member
Thread Starter
Join Date: Aug 2007
Location: Kingswinford, UNITED KINGDOM
Posts: 67
Likes: 0
Received 0 Likes
on
0 Posts
Boomerang nano thrust line problem?
I have some interesting flight characteristics. Frankly I don't have any experience with setup problems like this, but am sure you guys do 
On 2/3rds throttle the plane is trimmed fine, but requires quite a lot of nose down trim (approximately half of the available trim). But when I fly upside down it wants to fly into the ground, and you have to hold the nose up.
On full throttle the plane wants to climb quite a lot. When I cut the throttle to idle the plane want to dive .
I thought it was a COG problem, and I moved the cog forward by adding lead to the nose area. Its now at 285mm 11 1/4" forward of the wing/flap trailing edge (header full, main tank 1/2"), which I think is considered optimal. This mean I could reduce some of the nose down trim, but the problem persists.
I am now starting to wonder if it could be a thrust line problem. My turbine is currently angled 4 degrees down (as measured by iPhone!) relative to the top part of the airframe (where it joins the canopy).
Is it a classic thrust line problem? Is there a link to the proper way to measure the thrust line?
I know others here have lots of experience sorting problem like this, so I am open to any advice. Its not a huge problem, and I realise I can fly round it, but I would be nice to feel like it wants to fly upside down !
On 2/3rds throttle the plane is trimmed fine, but requires quite a lot of nose down trim (approximately half of the available trim). But when I fly upside down it wants to fly into the ground, and you have to hold the nose up.
On full throttle the plane wants to climb quite a lot. When I cut the throttle to idle the plane want to dive .
I thought it was a COG problem, and I moved the cog forward by adding lead to the nose area. Its now at 285mm 11 1/4" forward of the wing/flap trailing edge (header full, main tank 1/2"), which I think is considered optimal. This mean I could reduce some of the nose down trim, but the problem persists.
I am now starting to wonder if it could be a thrust line problem. My turbine is currently angled 4 degrees down (as measured by iPhone!) relative to the top part of the airframe (where it joins the canopy).
Is it a classic thrust line problem? Is there a link to the proper way to measure the thrust line?
I know others here have lots of experience sorting problem like this, so I am open to any advice. Its not a huge problem, and I realise I can fly round it, but I would be nice to feel like it wants to fly upside down !
08-19-2012, 01:07 PM
#2
Member
Join Date: Jan 2008
Location: Pierantonio Umbertide, ITALY
Posts: 68
Likes: 0
Received 0 Likes
on
0 Posts
RE: Boomerang nano thrust line problem?
hy...... my nano had the same problem at first, with P60 at half throttle fly straigh and then when I apply full throttle it climb so fast.......
I've put 3 shim under the turbine bracket.......
now it still climb at full throttle but so gentle......
forgive me for my bad english languagge........
I've put 3 shim under the turbine bracket.......
now it still climb at full throttle but so gentle......
forgive me for my bad english languagge........
08-19-2012, 01:18 PM
#3
RE: Boomerang nano thrust line problem?
When you say on full throttle the plane wants to climb quite a lot. When I cut the throttle to idle the plane want to dive , are you inverted?
ORIGINAL: sieze2
I have some interesting flight characteristics. Frankly I don't have any experience with setup problems like this, but am sure you guys do
On 2/3rds throttle the plane is trimmed fine, but requires quite a lot of nose down trim (approximately half of the available trim). But when I fly upside down it wants to fly into the ground, and you have to hold the nose up.
On full throttle the plane wants to climb quite a lot. When I cut the throttle to idle the plane want to dive .
I thought it was a COG problem, and I moved the cog forward by adding lead to the nose area. Its now at 285mm 11 1/4" forward of the wing/flap trailing edge (header full, main tank 1/2"), which I think is considered optimal. This mean I could reduce some of the nose down trim, but the problem persists.
I am now starting to wonder if it could be a thrust line problem. My turbine is currently angled 4 degrees down (as measured by iPhone!) relative to the top part of the airframe (where it joins the canopy).
Is it a classic thrust line problem? Is there a link to the proper way to measure the thrust line?
I know others here have lots of experience sorting problem like this, so I am open to any advice. Its not a huge problem, and I realise I can fly round it, but I would be nice to feel like it wants to fly upside down !
I have some interesting flight characteristics. Frankly I don't have any experience with setup problems like this, but am sure you guys do
On 2/3rds throttle the plane is trimmed fine, but requires quite a lot of nose down trim (approximately half of the available trim). But when I fly upside down it wants to fly into the ground, and you have to hold the nose up.
On full throttle the plane wants to climb quite a lot. When I cut the throttle to idle the plane want to dive .
I thought it was a COG problem, and I moved the cog forward by adding lead to the nose area. Its now at 285mm 11 1/4" forward of the wing/flap trailing edge (header full, main tank 1/2"), which I think is considered optimal. This mean I could reduce some of the nose down trim, but the problem persists.
I am now starting to wonder if it could be a thrust line problem. My turbine is currently angled 4 degrees down (as measured by iPhone!) relative to the top part of the airframe (where it joins the canopy).
Is it a classic thrust line problem? Is there a link to the proper way to measure the thrust line?
I know others here have lots of experience sorting problem like this, so I am open to any advice. Its not a huge problem, and I realise I can fly round it, but I would be nice to feel like it wants to fly upside down !
08-19-2012, 01:38 PM
#4
Member
Thread Starter
Join Date: Aug 2007
Location: Kingswinford, UNITED KINGDOM
Posts: 67
Likes: 0
Received 0 Likes
on
0 Posts
RE: Boomerang nano thrust line problem?
No it want to dive when cut to idle and its the correct way up???
ORIGINAL: Justflying1
When you say on full throttle the plane wants to climb quite a lot. When I cut the throttle to idle the plane want to dive , are you inverted?
ORIGINAL: sieze2
I have some interesting flight characteristics. Frankly I don't have any experience with setup problems like this, but am sure you guys do
On 2/3rds throttle the plane is trimmed fine, but requires quite a lot of nose down trim (approximately half of the available trim). But when I fly upside down it wants to fly into the ground, and you have to hold the nose up.
On full throttle the plane wants to climb quite a lot. When I cut the throttle to idle the plane want to dive .
I thought it was a COG problem, and I moved the cog forward by adding lead to the nose area. Its now at 285mm 11 1/4'' forward of the wing/flap trailing edge (header full, main tank 1/2''), which I think is considered optimal. This mean I could reduce some of the nose down trim, but the problem persists.
I am now starting to wonder if it could be a thrust line problem. My turbine is currently angled 4 degrees down (as measured by iPhone!) relative to the top part of the airframe (where it joins the canopy).
Is it a classic thrust line problem? Is there a link to the proper way to measure the thrust line?
I know others here have lots of experience sorting problem like this, so I am open to any advice. Its not a huge problem, and I realise I can fly round it, but I would be nice to feel like it wants to fly upside down !
I have some interesting flight characteristics. Frankly I don't have any experience with setup problems like this, but am sure you guys do
On 2/3rds throttle the plane is trimmed fine, but requires quite a lot of nose down trim (approximately half of the available trim). But when I fly upside down it wants to fly into the ground, and you have to hold the nose up.
On full throttle the plane wants to climb quite a lot. When I cut the throttle to idle the plane want to dive .
I thought it was a COG problem, and I moved the cog forward by adding lead to the nose area. Its now at 285mm 11 1/4'' forward of the wing/flap trailing edge (header full, main tank 1/2''), which I think is considered optimal. This mean I could reduce some of the nose down trim, but the problem persists.
I am now starting to wonder if it could be a thrust line problem. My turbine is currently angled 4 degrees down (as measured by iPhone!) relative to the top part of the airframe (where it joins the canopy).
Is it a classic thrust line problem? Is there a link to the proper way to measure the thrust line?
I know others here have lots of experience sorting problem like this, so I am open to any advice. Its not a huge problem, and I realise I can fly round it, but I would be nice to feel like it wants to fly upside down !
08-20-2012, 01:24 AM
#6
Member
Join Date: Jun 2006
Location: , NEW ZEALAND
Posts: 68
Likes: 0
Received 0 Likes
on
0 Posts
RE: Boomerang nano thrust line problem?
Is your rear stab seated properly? My turbine is angled down as well but don't have any issues although I did have trim issues at one stage which I put down to not seating the rear stab properly (the elevator cable had got caught up when I put it together).
The only other thing I can think off is the boom holes might not be drilled in the right spot but that's just a guess. Good luck
The only other thing I can think off is the boom holes might not be drilled in the right spot but that's just a guess. Good luck
08-20-2012, 04:14 AM
#7
RE: Boomerang nano thrust line problem?
Make sure the ailerons are centered so you are not in "down" slightly.. little reflex is ok.. might have to shim tail and move Cg back a little.. Mine liked 10 3/4 inch.. Plane has alot of coupling, especially rudder to aileron, but rudder to pitch too, to the belly, so make sure the rudders are centered so its not coupling..
fly straight and level, put rudder in and see if it pitches.. I had to trim the rudders slightly OUT, and ailerons slightly up to get it quit doing that.
fly straight and level, put rudder in and see if it pitches.. I had to trim the rudders slightly OUT, and ailerons slightly up to get it quit doing that.
08-21-2012, 11:54 AM
#8
My Feedback: (25)
Join Date: Mar 2004
Location: Las Vegas, NV, ANGUILLA
Posts: 262
Likes: 0
Received 0 Likes
on
0 Posts
RE: Boomerang nano thrust line problem?
If it's ok at 2/3 throttle add a throttle curve mix with elevator that will add down elevator as the throttle is advanced. Cured mine.
Mike
Mike
08-21-2012, 12:49 PM
#10
My Feedback: (25)
Join Date: Mar 2004
Location: Las Vegas, NV, ANGUILLA
Posts: 262
Likes: 0
Received 0 Likes
on
0 Posts
RE: Boomerang nano thrust line problem?
Works fine...I have Jet Central Super Bee that spools up quickly. Mix cures zooming at high throttle even on missed approach...truth be told I have only about 4-5% down at full throttle which will not cause pronounced diving if that's what you're worried about.
Mike
Mike
08-22-2012, 04:56 PM
#12
My Feedback: (1)
Join Date: Dec 2002
Location: Co. Donegal, IRELAND
Posts: 2,760
Received 0 Likes
on
0 Posts
RE: Boomerang nano thrust line problem?
To check your engine thrust line you should trim for level flight at full throttle, then do a pass flat out and chop the throttle, if it dives you have to increase the amount the tailcone points down if it climbs up then you need to reduce it.
If your cg is correct and you have the tailcone of the turbine pointing down 3-5 deg and your control surface neutrals are correct then the only other thing it could be is tail incidence.
If your cg is correct and you have the tailcone of the turbine pointing down 3-5 deg and your control surface neutrals are correct then the only other thing it could be is tail incidence.
