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vettin74(at)yahoo.com
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 Posted: Fri Feb 29, 2008 10:47 am Post subject: New trim system and pitch stability... |
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To the Group,<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />
Arion Aircraft has finished flight testing of the servo driven trim tab in the elevator, more of a conventional trim system. Results were with out a doubt outstanding and worth the effort.
We have had some comments that the aircraft was responsive in pitch and or lacked the ability to be properly trimmed. The bungee trim system was designed to be simple to build and to trim off control pressures in flight, it also did good job of trimming airspeed although not always accurate due to the set up of the bungees. We have designed a servo operated trim tab internally mounted in the elevator. Using a ray allen servo and small push rod to drive a tab. I will run thru the results for one or two of the airspeeds selected. We did a full range of testing from 70mph up to 150mph IAS. The test were done in 10mph increments and the same tests were run at each airspeed.
For a trimmed airspeed of 110 mph IAS hands off flight. If a pull was initiated to 15 degrees above the horizon and power remained the same, than the stick released , the aircraft would start to decelerate to 100 pitch over and continue to 110 mph, after 15 seconds or so and a few pitch oscillations the aircraft would continue at 110 mph IAS hands off as when started.
If at 110 mph IAS and a push of 15 degrees nose down was initiated with the power constant and the stick released, the aircraft would accelerate some to 120 or so and begin a pitch up, again after a few oscillation the aircraft would regain the trimmed speed and continue hands off on its way.
When trimmed for 110 mph IAS and a reduction in power made, the aircraft will pitch down accelerate to 120 or so than begin to pitch back to 110, after a 15 sec or so the aircraft will find 110 mph IAS but in a glide as expected.
When trimmed for 110 mph IAS and power is applied, the aircraft will begin a pitch up slowing to around 100 mph IAS before the nose drops to around 110 and the aircraft continues in a climb at 110 mph IAS.
At higher airspeeds than 110 the aircraft did show all the same results except that the correcting tendency was a bit slower but did happen as described above and always came back to its trimmed configuration.
At speeds slower than 110 the recovery of the aircraft was quicker in all cases.
.
If trimmed for 110 mph IAS, any airspeed higher than 110 mph IAS required and push of the stick to hold that airspeed, for 10 above it was about 3 lbs stick force and 20 above about 5-7 lbs.
Any airspeed slower than 110mph IAS required a pull to maintain, speed of 10 or less were 3-5lbs stick force and speeds as slow as 30 less than trimmed requires 7-10lbs stick force.
Again this was performed at all airspeeds with the same results.
All airspeeds in the range were tested in the same manner as well as different flight configurations with the same results as above.
As some know from reading this list and those few who have flown the prototype aircraft, know the pitch forces to be light in that aircraft, the removal of the bungee system has increased the pitch force required in this aircraft by 3lbs per g or so….this means that this stick feel Is heavier and the aircraft less sensitive in pitch than before. I would expect the same results with the kits as well.
The bungees as well as providing control pressure trim did give some stick assist if you will that caused the aircraft to feel more sensitive than it is and less stable than it actually is. The new trim gives good positive feed back and controls pressures.
The end result of the new trim systems is that the aircraft is much easier to trim, It will hold a trimmed airspeed much better and will be easier to fly on long cross countries.
The pitch stability of the aircraft is positive both stick free and stick fixed at all airspeeds. It shows good recovery tendency back to a trimmed speed after a disruption in angle of attack, power, stick placement, ect
These tendencies were always inherent, the prototype does not have the longer motor mount, the pitch geometry is not changed ( although if it was would only heavy up the stick pressures not change these results) and is certainly at an aft CG situation for flight testing. A CG movement forward will only increase its ability to self correct or hold a trimmed airspeed. In other words the aircraft was flown in the worst condition it could be and showed positive results.
The good flying qualities of the lightning with the bungee trim have only been improved upon by the use of this more conventional trim system making it even more a joy to fly…..and believe me I had some fun while I was up there!
We are currently fitting the system to our 2008 demo and this will be at Sun N Fun 08 for demos. The system is retrofit table to any lightning current or in progress.
We also will be working on a price for the kit. Those who are building the aircraft and have not flown, we will be working out an exchange for the old trim motor as credit for the new trim kit if wanted, as it is also the flap motor and can be used in other installations, this is only if the motor is new and in unused condition and has not been flown……
I am sure that many question will arise and some more about the flight testing done, please post comments or email me or the group directly as to any questions you have…….
Nick Otterback
Research and Development
Arion Aircraft, LLC
[quote][b]
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pequeajim
Joined: 03 Sep 2006
Posts: 708
Location: New Holland, PA
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| Posted: Fri Feb 29, 2008 2:52 pm Post subject: New trim system and pitch stability... |
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Great news Nick!
Just a few questions that some other people may have also.
1. If this is an internally mounted servo, then how big a hole will I
need to cut in the elevator half to mount the servo, and for pushrod
clearance? My elevators and stab are already painted, but this can still be
done.
2. If a hole is cut, is it from the bottom side?
3. The actual trim tab; is it added to, or cut from the elevator
training edge?
Thanks again for presenting us with some nice options.
Jim!
From: owner-lightning-list-server(at)matronics.com
[mailto:owner-lightning-list-server(at)matronics.com] On Behalf Of nick
otterback
Sent: Friday, February 29, 2008 11:58 AM
To: lightning-list(at)matronics.com
Subject: New trim system and pitch stability...
To the Group,
Arion Aircraft has finished flight testing of the servo driven trim tab in
the elevator, more of a conventional trim system. Results were with out a
doubt outstanding and worth the effort.
We have had some comments that the aircraft was responsive in pitch and or
lacked the ability to be properly trimmed. The bungee trim system was
designed to be simple to build and to trim off control pressures in flight,
it also did good job of trimming airspeed although not always accurate due
to the set up of the bungees. We have designed a servo operated trim tab
internally mounted in the elevator. Using a ray allen servo and small push
rod to drive a tab. I will run thru the results for one or two of the
airspeeds selected. We did a full range of testing from 70mph up to 150mph
IAS. The test were done in 10mph increments and the same tests were run at
each airspeed.
For a trimmed airspeed of 110 mph IAS hands off flight. If a pull was
initiated to 15 degrees above the horizon and power remained the same, than
the stick released , the aircraft would start to decelerate to 100 pitch
over and continue to 110 mph, after 15 seconds or so and a few pitch
oscillations the aircraft would continue at 110 mph IAS hands off as when
started.
If at 110 mph IAS and a push of 15 degrees nose down was initiated with the
power constant and the stick released, the aircraft would accelerate some to
120 or so and begin a pitch up, again after a few oscillation the aircraft
would regain the trimmed speed and continue hands off on its way.
When trimmed for 110 mph IAS and a reduction in power made, the aircraft
will pitch down accelerate to 120 or so than begin to pitch back to 110,
after a 15 sec or so the aircraft will find 110 mph IAS but in a glide as
expected.
When trimmed for 110 mph IAS and power is applied, the aircraft will begin a
pitch up slowing to around 100 mph IAS before the nose drops to around 110
and the aircraft continues in a climb at 110 mph IAS.
At higher airspeeds than 110 the aircraft did show all the same results
except that the correcting tendency was a bit slower but did happen as
described above and always came back to its trimmed configuration.
At speeds slower than 110 the recovery of the aircraft was quicker in all
cases.
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info(at)flylightning.net
Guest
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| Posted: Fri Feb 29, 2008 4:55 pm Post subject: New trim system and pitch stability... |
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Jim,
I guess it is the type of builder you are. It will be a tab added o the rear
of the elevator ,but when finished does not look bad at all, if one wanted
you could make it flush using the same dimensions that the tab we are
providing is..The hole is in the bottom of the elevator and about 3.5 by 3.5
and than make a flush cover for it...
Nick
_____
From: owner-lightning-list-server(at)matronics.com
[mailto:owner-lightning-list-server(at)matronics.com] On Behalf Of Jim Langley
Sent: Friday, February 29, 2008 2:34 PM
To: lightning-list(at)matronics.com
Subject: RE: New trim system and pitch stability...
Great news Nick!
Just a few questions that some other people may have also.
1. If this is an internally mounted servo, then how big a hole will I
need to cut in the elevator half to mount the servo, and for pushrod
clearance? My elevators and stab are already painted, but this can still be
done.
2. If a hole is cut, is it from the bottom side?
3. The actual trim tab; is it added to, or cut from the elevator
training edge?
Thanks again for presenting us with some nice options.
Jim!
From: owner-lightning-list-server(at)matronics.com
[mailto:owner-lightning-list-server(at)matronics.com] On Behalf Of nick
otterback
Sent: Friday, February 29, 2008 11:58 AM
To: lightning-list(at)matronics.com
Subject: New trim system and pitch stability...
To the Group,
Arion Aircraft has finished flight testing of the servo driven trim tab in
the elevator, more of a conventional trim system. Results were with out a
doubt outstanding and worth the effort.
We have had some comments that the aircraft was responsive in pitch and or
lacked the ability to be properly trimmed. The bungee trim system was
designed to be simple to build and to trim off control pressures in flight,
it also did good job of trimming airspeed although not always accurate due
to the set up of the bungees. We have designed a servo operated trim tab
internally mounted in the elevator. Using a ray allen servo and small push
rod to drive a tab. I will run thru the results for one or two of the
airspeeds selected. We did a full range of testing from 70mph up to 150mph
IAS. The test were done in 10mph increments and the same tests were run at
each airspeed.
For a trimmed airspeed of 110 mph IAS hands off flight. If a pull was
initiated to 15 degrees above the horizon and power remained the same, than
the stick released , the aircraft would start to decelerate to 100 pitch
over and continue to 110 mph, after 15 seconds or so and a few pitch
oscillations the aircraft would continue at 110 mph IAS hands off as when
started.
If at 110 mph IAS and a push of 15 degrees nose down was initiated with the
power constant and the stick released, the aircraft would accelerate some to
120 or so and begin a pitch up, again after a few oscillation the aircraft
would regain the trimmed speed and continue hands off on its way.
When trimmed for 110 mph IAS and a reduction in power made, the aircraft
will pitch down accelerate to 120 or so than begin to pitch back to 110,
after a 15 sec or so the aircraft will find 110 mph IAS but in a glide as
expected.
When trimmed for 110 mph IAS and power is applied, the aircraft will begin a
pitch up slowing to around 100 mph IAS before the nose drops to around 110
and the aircraft continues in a climb at 110 mph IAS.
At higher airspeeds than 110 the aircraft did show all the same results
except that the correcting tendency was a bit slower but did happen as
described above and always came back to its trimmed configuration.
At speeds slower than 110 the recovery of the aircraft was quicker in all
cases.
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davemcc
Joined: 28 Feb 2007
Posts: 74
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| Posted: Wed Mar 05, 2008 5:33 am Post subject: New trim system and pitch stability... |
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Nick
The trim sounds great, it is nice to counter the force at the source rather than through hinges and controls. In cold Mn. the bungee will stay "frozen" or extended and be useless.
will it fit the Esqual, if so I want one
Thanks Nick
Dave Mc
[quote] ---
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info(at)flylightning.net
Guest
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| Posted: Wed Mar 05, 2008 3:02 pm Post subject: New trim system and pitch stability... |
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Dave,
Certainly will fit the esqual ...i can put you on the list..will be a weeks
or 2 before we get parts.
nick
_____
From: owner-lightning-list-server(at)matronics.com
[mailto:owner-lightning-list-server(at)matronics.com] On Behalf Of Dave
Sent: Wednesday, March 05, 2008 7:30 AM
To: lightning-list(at)matronics.com
Subject: Re: New trim system and pitch stability...
Nick
The trim sounds great, it is nice to counter the force at the source rather
than through hinges and controls. In cold Mn. the bungee will stay "frozen"
or extended and be useless.
will it fit the Esqual, if so I want one
Thanks Nick
Dave Mc
---
| | - The Matronics Lightning-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Lightning-List |
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