Nimbus 2B flaps/trim

[Airbuh]

Gents, Aaron Thomson here. I used to run Morgan Valley Soaring in Morgan UT.. After starting a career with Delta Air Lines and starting a family I have returned to soaring and recently purchased a Nimbus 2B. I've had my first successful flight but noticed something odd about the flaps and the elevator trim. My Nimbus has a flap handle that is located on the left side of the seat pan. That being said as many of you Schempp Hirth guys know the elevator trim is located in the same location and is connected to the flaps to provide less need for trimming when changing flap settings. What I have observed is that I can't move the flap position at all when the green trim knob is tightened down. If I loosen the trim knob and take it out of the trim detents I can now change flap settings. This seems odd to me but I thought I would seek advice from the experts!
Can someone clarify this for me?

Aaron Thomson,
Nimbus 2B N71TT
S/N 136

[[email protected]]

That's not right. I have a Ventus C and once you set the trim you can move the flaps all day and not have to touch the trim. While this is not a Nimbus 2, I have flown a Nimbus 2 and this is definitely not right. Have a knowledgeable mechanic look at it.

Bob
BV



On Tuesday, September 12, 2017 at 10:06:52 AM UTC-7, Aaron Thomson wrote:
> Gents, Aaron Thomson here. I used to run Morgan Valley Soaring in Morgan UT. After starting a career with Delta Air Lines and starting a family I have returned to soaring and recently purchased a Nimbus 2B. I've had my first successful flight but noticed something odd about the flaps and the elevator trim. My Nimbus has a flap handle that is located on the left side of the seat pan. That being said as many of you Schempp Hirth guys know the elevator trim is located in the same location and is connected to the flaps to provide less need for trimming when changing flap settings. What I have observed is that I can't move the flap position at all when the green trim knob is tightened down. If I loosen the trim knob and take it out of the trim detents I can now change flap settings. This seems odd to me but I thought I would seek advice from the experts!
> Can someone clarify this for me?
>
> Aaron Thomson,
> Nimbus 2B N71TT
> S/N 136

[Mike C]

On Tuesday, September 12, 2017 at 11:06:52 AM UTC-6, Aaron Thomson wrote:
> Gents, Aaron Thomson here. I used to run Morgan Valley Soaring in Morgan UT. After starting a career with Delta Air Lines and starting a family I have returned to soaring and recently purchased a Nimbus 2B. I've had my first successful flight but noticed something odd about the flaps and the elevator trim. My Nimbus has a flap handle that is located on the left side of the seat pan. That being said as many of you Schempp Hirth guys know the elevator trim is located in the same location and is connected to the flaps to provide less need for trimming when changing flap settings. What I have observed is that I can't move the flap position at all when the green trim knob is tightened down. If I loosen the trim knob and take it out of the trim detents I can now change flap settings. This seems odd to me but I thought I would seek advice from the experts!
> Can someone clarify this for me?
>
> Aaron Thomson,
> Nimbus 2B N71TT
> S/N 136

Hi Aaron,

The flap control and elevator trim on my Mini Nimbus, although located close to each other, are independent. Once set the trim position does not effect the flap movement and flap movement does not effect the trim in any way.

Mike

[Aaron Thomson]

Thanks for the input, it sure doesn't seem right to me. I am an A&P and I need to investigate further. Looks I'll need to pull the seat pan and figure it out. Just wanted to make sure I wasn't missing something.


Aaron Thomson

[Aaron Thomson]

Hey Mike my trim appears to be flap position compensated, I am going to pull the seat pan and figure this thing out. I have to wonder if the trim screw has been replaced and could be too long and thus interfering with the flap control tube. Not sure why it's doing what it is, but it sure doesn't feel right to me.

Aaron Thomson

[Alex[_6_]]

On many Schempp-Hirth gliders the trim moves with flap settings - flaps negative moves the trim forward and flaps positive moves the trim back. The advertised idea being that you only set trim once.

I believe the trim lever is mounted on sliding tube on the flaps rod. Possibly corrosion and/or missing lubrication blocks the sliding mechanism causing the interconnection.

[[email protected]]

,"If I loosen the trim knob and take it out of the trim detents"

I have not directly looked at the nimbus 2 but all the other Schemp-hirth products I have looked at, do not have trim detents. My ventus b has a sliding knob that is located on the flap sliding tube and moves with the flap handle. when tightened this makes (thru the use of a spring attached to the elevator circuit) the control stick have pressure fore and aft according to stick position. But the flap position is not hindered unless you hold the stick from moving. Then only deterred by spring tension. So definitely something wrong there.

CH

[Mike C]

On Wednesday, September 13, 2017 at 8:14:07 AM UTC-6, wrote:
> ,"If I loosen the trim knob and take it out of the trim detents"
>
> I have not directly looked at the nimbus 2 but all the other Schemp-hirth products I have looked at, do not have trim detents. My ventus b has a sliding knob that is located on the flap sliding tube and moves with the flap handle. when tightened this makes (thru the use of a spring attached to the elevator circuit) the control stick have pressure fore and aft according to stick position. But the flap position is not hindered unless you hold the stick from moving. Then only deterred by spring tension. So definitely something wrong there.
>
> CH

Similar to my Mini C, but it has detents. Set the trim at best L/D and forget it. All flap settings will have 'approximately' the same amount of stick pressure at any speed.

[Aaron Thomson]

Thanks Alex, I will be looking closely at the flap tube where the trim is located for proper operation and lubrication.

Aaron Thomson

[Aaron Thomson]

Thanks Cliff,

I agree, my Nimbus should work as you described. I hope to find something wrong and either lube it or make sure it's operation properly.

Kind Regards,

Aaron Thomson

[Aaron Thomson]

Thanks Mike,

Sounds like I am on the same page as you. I'm anxious to find the problem and get it operating properly.

Aaron Thomson

[Mike C]

On Wednesday, September 13, 2017 at 1:44:18 PM UTC-6, Aaron Thomson wrote:
> Thanks Mike,
>
> Sounds like I am on the same page as you. I'm anxious to find the problem and get it operating properly.
>
> Aaron Thomson

Aaron,

Removing the seat pan is a drag but I do it every year for the condition inspection.

You may find there is minor corrosion or dried up grease that is easy to clean up and lightly lube again. Hope that is all it is. The Nimbus is a neat older sailplane.

Mike

[Aaron Thomson]

After a thorough inspection of the flaps/trim issue, I found that the trim screw was able to bottom out on the flap actuation rod. A simple thin brass washer provided just the right amount separation without losing the trim detents and their ability to hold the trim in place while moving the flap handle through all available settings. Thanks all for the suggestions and wonderful support! STAY SAFE!

Aaron Thomson
N71TT Nimbus 2B

[Mike C]

On Saturday, September 23, 2017 at 8:00:18 PM UTC-6, Aaron Thomson wrote:
> After a thorough inspection of the flaps/trim issue, I found that the trim screw was able to bottom out on the flap actuation rod. A simple thin brass washer provided just the right amount separation without losing the trim detents and their ability to hold the trim in place while moving the flap handle through all available settings. Thanks all for the suggestions and wonderful support! STAY SAFE!
>
> Aaron Thomson
> N71TT Nimbus 2B

Have fun Aaron!!