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Search: Posts Made By: NickLappos
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Forum: Rotorheads
16th Oct 2005, 04:46
Replies: 840
Views: 320,496
Posted By NickLappos

Shawn, Actually, the 430 has twin sets of WAT...

Shawn,
Actually, the 430 has twin sets of WAT curves, one set ( a pair of IGE and OGE hover charts) allows "wind from any azimuth" and the other set shows gross weights about 500 lbs more, and is...
Forum: Rotorheads
12th Oct 2005, 20:05
Replies: 840
Views: 320,496
Posted By NickLappos

212man, No pity here, Bell uses a different...

212man,
No pity here, Bell uses a different philosophy with everything, consistent with holding down the lower cost end of the market (that is not a slur, someone has to fill that market slice!)
...
Forum: Rotorheads
11th Oct 2005, 13:19
Replies: 840
Views: 320,496
Posted By NickLappos

Squirrel and Arm, The use of the governor to...

Squirrel and Arm,

The use of the governor to help controllability is a great idea, much in keeping with the idea that the total machine should respond to the mission.

I have personally worked...
Forum: Rotorheads
10th Oct 2005, 09:37
Replies: 840
Views: 320,496
Posted By NickLappos

good story, 3top! the maximum rotor thrust...

good story, 3top!

the maximum rotor thrust drops by the square of the rotor rpm, so that at 70% rotor, the max thrust is about half what it is at 100% (0.70 x0.70 = 0.49).
Forum: Rotorheads
9th Oct 2005, 15:25
Replies: 840
Views: 320,496
Posted By NickLappos

the difference is very important: In a helo...

the difference is very important:

In a helo prone to LTE, the machine screws you

In a machine experiencing LTA, you screw the machine.

Recovery from LTA involves reducing power (torque) down...
Forum: Rotorheads
7th Oct 2005, 20:45
Replies: 840
Views: 320,496
Posted By NickLappos

BigMike, I really do not know of any 206III...

BigMike,

I really do not know of any 206III LTE events, perhaps the redesign did help. It could be that it only covered the power/gross weight increases, however.

Please do not misread me on...
Forum: Rotorheads
7th Oct 2005, 18:41
Replies: 840
Views: 320,496
Posted By NickLappos

Some explanation of how LTE occurs: 1) Every...

Some explanation of how LTE occurs:

1) Every tail rotor has minor variations in its thrust output, based on the precise flow it is experiencing. If you put some turbulence into a rotor, the...
Forum: Rotorheads
7th Oct 2005, 08:04
Replies: 840
Views: 320,496
Posted By NickLappos

Two comments: Use the controls to the...

Two comments:

Use the controls to the fullest. It is not LTE if you don't use the pedal all the way, it is "shy pilot". I have tested helos for 30 years, and hit every stop on every control at...
Forum: Rotorheads
6th Oct 2005, 14:39
Replies: 840
Views: 320,496
Posted By NickLappos

headsethair, You are certainly right that...

headsethair,

You are certainly right that there is lots of middle ground, and one should fly appropriate to the type he is strapped into.

I just want to be sure that we don't tar all helos with...
Forum: Rotorheads
5th Oct 2005, 14:07
Replies: 840
Views: 320,496
Posted By NickLappos

Flingwing207, Your logic, if carried to...

Flingwing207,
Your logic, if carried to extreme:
If you bash your tail cone into a mountain along the right side, and your aircraft yaws right and "does not subside of its own accord and, if not...
Forum: Rotorheads
3rd Oct 2005, 02:56
Replies: 840
Views: 320,496
Posted By NickLappos

Most LTE's are due to rotor rpm drooping when too...

Most LTE's are due to rotor rpm drooping when too much power is commanded. Lowering the rpm reduces the available tail rotor authority, and is really not LTE, but rather over-pitching, a good...
Forum: Rotorheads
16th Jun 2005, 15:41
Replies: 840
Views: 320,496
Posted By NickLappos

chopperdr, If that loose change are Franc...

chopperdr,

If that loose change are Franc coins, it means someone has found a use for the Franc!

If you guys would like, I can post some comments on the type of absorbers commonly used.
Forum: Rotorheads
16th Jun 2005, 13:01
Replies: 840
Views: 320,496
Posted By NickLappos

TheFlyingSquirrel- That thing is a...

TheFlyingSquirrel-


That thing is a vertical vibration absorber, designed to "twang" probably at 4 per revolution frequency, kind of like a person standing on a diving board can make the board...
Forum: Rotorheads
14th Jun 2005, 16:57
Replies: 840
Views: 320,496
Posted By NickLappos

SASless, you used to complain about barebones...

SASless, you used to complain about barebones aircraft flogging around the patch at night, now you say that barebones aircraft are better (is that a gotcha?)
Forum: Rotorheads
29th Mar 2005, 03:42
Replies: 840
Views: 320,496
Posted By NickLappos

Gray Area, Inadequate is the definition of a...

Gray Area,
Inadequate is the definition of a rotor that can be bent by the pilot during relatively normal maneuvers. This is not hypothetical, it is (according to you) why the hydraulics were...
Forum: Rotorheads
29th Mar 2005, 00:48
Replies: 840
Views: 320,496
Posted By NickLappos

Gray Area said: "Eurocopter will argue that the...

Gray Area said:
"Eurocopter will argue that the hydraulic system is designed to ensure that the rotor head cannot be overstressed. Something that in the early days of the Starflex head was paramount...
Forum: Rotorheads
27th Mar 2005, 17:23
Replies: 840
Views: 320,496
Posted By NickLappos

Sandy, Good question! Any EC people out...

Sandy,

Good question! Any EC people out there who can answer?
Forum: Rotorheads
26th Mar 2005, 17:17
Replies: 840
Views: 320,496
Posted By NickLappos

407, The elastomers are not any stiffer...

407,

The elastomers are not any stiffer while in flight, because the internal heating from the flexure is quite sufficient. In any case, the stiffness of the elastomer is a very tiny force...
Forum: Rotorheads
25th Mar 2005, 16:16
Replies: 840
Views: 320,496
Posted By NickLappos

Devil, Were that "engine transparency" the...

Devil,

Were that "engine transparency" the howls would start. That it is "servo transparency" makes it ok!

I think it is properly labeled "servo inadequacy".
Forum: Rotorheads
24th Mar 2005, 21:24
Replies: 840
Views: 320,496
Posted By NickLappos

Brian Abraham said: "An interesting discussion....

Brian Abraham said:
"An interesting discussion. Our company employed a few senior ex army Blackhawk instructors and jack stall was a frequent topic of theirs and related a number of accidents which...
Forum: Rotorheads
12th Dec 2004, 09:37
Replies: 840
Views: 320,496
Posted By NickLappos

4dogs, Thanks for the link to the past! It...

4dogs,

Thanks for the link to the past! It is interesting to see that old topics don't just go away!

I have to note one issue with your comment,"did all sorts of things in the AS350 that...
Forum: Rotorheads
4th Dec 2004, 04:46
Replies: 840
Views: 320,496
Posted By NickLappos

devil 49, The reason for the jack stall is...

devil 49,

The reason for the jack stall is that the blades are stalling, and when they do, they progressively add more and more force to the swashplate. This is due to the pitching moment of the...
Forum: Rotorheads
2nd Dec 2004, 23:33
Replies: 840
Views: 320,496
Posted By NickLappos

ATN, I certainly don't want this to become an...

ATN,
I certainly don't want this to become an us and them thing. I believe that the servo strength of virtually every helicopter I know, civil and military, does not show any jack stall in regions...
Forum: Rotorheads
2nd Dec 2004, 19:22
Replies: 840
Views: 320,496
Posted By NickLappos

The terms can confuse you. We call it servo...

The terms can confuse you. We call it servo stalling, or jack stalling but "'Transparency" is a good ephimistic way to describe the same thing - the servo reaches its maximum force and then passes...
Forum: Rotorheads
2nd Dec 2004, 12:47
Replies: 840
Views: 320,496
Posted By NickLappos

The symptoms of jack stall are caused by blade...

The symptoms of jack stall are caused by blade stall pitch change link loads pushing through the servo, not by fluid supply limits. The hydraulic pressure warning lights would illuminate if the pump...
Forum: Rotorheads
1st Dec 2004, 20:37
Replies: 840
Views: 320,496
Posted By NickLappos

Disguise, What altitude, OAT, Indicated Air...

Disguise,

What altitude, OAT, Indicated Air Speed and gross weight were you when this occurred?

Collective Bias,

I think your description is quite correct, but let me translate the logic...
Forum: Rotorheads
1st Dec 2004, 19:13
Replies: 840
Views: 320,496
Posted By NickLappos

It is the term to describe when the blades...

It is the term to describe when the blades overpower the hydraulic servos, causing the controls to whip around, and usually causing control loss.

It is the product of having servo hydraulics that...
Forum: Rotorheads
12th Nov 2004, 12:22
Replies: 840
Views: 320,496
Posted By NickLappos

Jonathon Swift wrote a whole book about the...

Jonathon Swift wrote a whole book about the ability to argue about arbitrary things!
As lately seen, Americans go Right when more power is added, the French and Russians have always gone Left!
Forum: Rotorheads
16th Sep 2004, 04:31
Replies: 840
Views: 320,496
Posted By NickLappos

Devil49, Thanks for that info, it does seem...

Devil49,

Thanks for that info, it does seem to me the comments center around a yaw control that is both powerful and sensitive, and that we are talking about a bit of Pilot Induced Oscillation -...
Forum: Rotorheads
11th Sep 2004, 20:49
Replies: 840
Views: 320,496
Posted By NickLappos

as355f1 It is an old belief that the height...

as355f1

It is an old belief that the height of the main rotor vs the height of the tail rotor is a reason for hovering one skid/wheel down, this is really not correct. All the forces developed by...
Showing results 1 to 30 of 30


 
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