PPRuNe Forums - Search Results

Go Back  PPRuNe Forums > Search Forums
Reload this Page >

Search Results

Search: Posts Made By: MeddlMoe
Showing results 1 to 34 of 34
Search took 0.00 seconds.
Forum: Rotorheads
18th Nov 2021, 10:14
Replies: 6
Views: 2,430
Posted By MeddlMoe

AW169 AW139 with real OEI landing

Hello Everybody,

There is one thing I have been discussing with a collegue:

The MPM of AW169 and AW139 mention lifetime penalty factors for CAT.A training mode.

Do you know the lifetime...
Forum: Rotorheads
15th Sep 2021, 09:00
Replies: 272
Views: 66,660
Posted By MeddlMoe

Isn't a flag on the starboard side supposed to be...

Isn't a flag on the starboard side supposed to be backwards?
Forum: Rotorheads
20th Aug 2021, 11:26
Replies: 9
Views: 2,895
Posted By MeddlMoe

Interesting, have you tried recording the sounds...

Interesting, have you tried recording the sounds and replaying them?

We have lots of crows at my work place, but they don't seem to be disturbed by any of the helicopters (no chinook). They do...
Forum: Rotorheads
21st Jul 2021, 16:19
Replies: 440
Views: 138,428
Posted By MeddlMoe

A cyclic input will tilt both rotors in the same...

A cyclic input will tilt both rotors in the same direction. Therefore the clearance will stay approximately the same.

That being said, I think the coaxial rotor idea is not very good. A lot more...
Forum: Rotorheads
13th Jul 2021, 15:30
Replies: 19
Views: 5,800
Posted By MeddlMoe

Many of the lift and cruise concepts for eVTOLs...

Many of the lift and cruise concepts for eVTOLs want to stop the propellers in forward flight. A single blade propeller may be usefull, because it could implement a flapping hinge, while still...
Forum: Rotorheads
8th Jul 2021, 15:31
Replies: 200
Views: 82,241
Posted By MeddlMoe

This is Lilium in a nutshell The performance...

This is Lilium in a nutshell

The performance claims are made up.
The time line for entry into service is made up.
The physics are made up
Forum: Rotorheads
22nd Apr 2021, 11:45
Replies: 21
Views: 5,074
Posted By MeddlMoe

I just picked a familiar looking graph from...

I just picked a familiar looking graph from google :-)

Thank you for the pointer to the YUH-61. I did not know about that one.
Forum: Rotorheads
22nd Apr 2021, 11:09
Replies: 21
Views: 5,074
Posted By MeddlMoe

I don`t know the huey rotor system, but I assume...

I don`t know the huey rotor system, but I assume that the rotation frequency crosses the blade lead-lag resonance.

The lead-lag resonance frequency increases with increasing rotor speed, but not...
Forum: Rotorheads
1st Apr 2021, 17:15
Replies: 14
Views: 2,317
Posted By MeddlMoe

The integrated solution is nice and compact, and...

The integrated solution is nice and compact, and you can use less tubing, so I thought that Eurocopter and Bell have a good reasons not to use them.

The front of the aircraft is ideal for dynamic...
Forum: Rotorheads
1st Apr 2021, 10:35
Replies: 14
Views: 2,317
Posted By MeddlMoe

AW169 quality of altitude and air speed measurement

Hello all,

I saw that the AW169 has the static ports of the barometric system (altimeter) integrated in the pitot tubes, which is different from Eurocopter or Bell helicopters (at least those that...
Forum: Rotorheads
29th Mar 2021, 14:10
Replies: 201
Views: 55,841
Posted By MeddlMoe

The Airbus Racer configuration?

The Airbus Racer configuration?
Forum: Rotorheads
29th Mar 2021, 14:08
Replies: 201
Views: 55,841
Posted By MeddlMoe

This Technology is also very promising for...

This Technology is also very promising for hydrogen powered electric aircraft:
https://www.fraunhofer.de/en/press/research-news/2021/february-2021/hydrogen-powered-drives-for-e-scooters.html
Forum: Rotorheads
25th Feb 2021, 17:14
Replies: 20
Views: 4,064
Posted By MeddlMoe

This is not trivial, because there are also...

This is not trivial, because there are also differences in purchasing price and operating costs.

American Helicopters (Bell, Sikorsky): Very High purchasing price and high maintenance cost ...
Forum: Rotorheads
25th Feb 2021, 13:58
Replies: 10
Views: 3,526
Posted By MeddlMoe

Do you mean the shear bearings between the rotor...

Do you mean the shear bearings between the rotor blades and the main rotor head?
Forum: Rotorheads
22nd Feb 2021, 11:29
Replies: 10
Views: 3,526
Posted By MeddlMoe

Thank you, everybody!

Thank you, everybody!
Forum: Rotorheads
20th Feb 2021, 13:53
Replies: 10
Views: 3,526
Posted By MeddlMoe

HEMS missions with IFR (does this make a...

HEMS missions with IFR (does this make a difference?), with often heavy payload on short or intermediate distances (<100NM).
Forum: Rotorheads
19th Feb 2021, 16:09
Replies: 10
Views: 3,526
Posted By MeddlMoe

Vibrations on Bell 429, AW109 or H135

Hello,

Has anybody flown the Bell 429, AW109 and H135 or two of these and can compare their experience with vibrations and noise?

Thanks
Moe
Forum: Rotorheads
11th Jan 2021, 10:17
Replies: 1
Views: 2,091
Posted By MeddlMoe

https://france3-regions.francetvinfo.fr/provence-a...

https://france3-regions.francetvinfo.fr/provence-alpes-cote-d-azur/bouches-du-rhone/marseille/vitrolles-incendie-cours-secteur-airbus-helicopters-90-pompiers-sont-place-1913370.html
Forum: Rotorheads
10th Jan 2021, 10:38
Replies: 7
Views: 1,822
Posted By MeddlMoe

There is not an easy answer. Originally the...

There is not an easy answer.

Originally the time limits (30seconds, 2 minutes, 5minutes) were at least partly based on preventing engine parts from overheating. I think (but please don't quote me...
Forum: Rotorheads
9th Jan 2021, 14:09
Replies: 23
Views: 7,032
Posted By MeddlMoe

That is just stupid

That is just stupid
Forum: Rotorheads
8th Jan 2021, 14:45
Replies: 23
Views: 7,032
Posted By MeddlMoe

The numbers per flight hour for helicopters are...

The numbers per flight hour for helicopters are somewhere between commercial airlines and private small planes. If you go by traveled passenger miles there is a huge difference between commercial...
Forum: Rotorheads
24th Dec 2020, 10:37
Replies: 146
Views: 19,952
Posted By MeddlMoe

No I mean 180 degrees peak to peak. The...

No I mean 180 degrees peak to peak.

The maximum "rate of flap up" i.e. the vertical speed is reached at the end of upward cyclic component of the aerodynamic force that is controlled by the AoA,...
Forum: Rotorheads
23rd Dec 2020, 16:48
Replies: 146
Views: 19,952
Posted By MeddlMoe

Can you explain in more detail, why you think...

Can you explain in more detail, why you think that pure aerodynamic forces applied as a sinusoidal function of time would not lead to 180 degrees phase shift?

0 degrees - - >acceleration...
Forum: Rotorheads
23rd Dec 2020, 12:12
Replies: 146
Views: 19,952
Posted By MeddlMoe

No, this would only be the case if the flapping...

No, this would only be the case if the flapping hinge offset was zero. The real flapping hinge offset is 2-6% for articulated rotors and 6-18% for "rigid" rotors (hingeless or flexbeam rotors)
...
Forum: Rotorheads
23rd Dec 2020, 11:57
Replies: 146
Views: 19,952
Posted By MeddlMoe

The off axis torque that is induced in a rotor...

The off axis torque that is induced in a rotor system is the cyclic component of the aeodynamic forces. This creates extra lift on one side of the mast and reduced lift on the other side. Lets say...
Forum: Rotorheads
21st Dec 2020, 21:50
Replies: 146
Views: 19,952
Posted By MeddlMoe

Congratulations, you have hereby explained how...

Congratulations, you have hereby explained how the gyroscopic effect works on a rotor blade.

What is next? There is no such thing as friction, it is just collisions between micro-structures and...
Forum: Rotorheads
20th Dec 2020, 14:15
Replies: 146
Views: 19,952
Posted By MeddlMoe

It just so happens that I used to work on rotor...

It just so happens that I used to work on rotor analysis for many years. I don't know what kind of engineers you have been talking to, but they seem to be not very good, or more likely you have...
Forum: Rotorheads
19th Dec 2020, 19:07
Replies: 146
Views: 19,952
Posted By MeddlMoe

Vessbot give it up! they are not going to...

Vessbot give it up!

they are not going to admit that they are wrong, and they won't engage in a physics based discussion.

They will ignore the phsics parts of your arguments the same way they...
Forum: Rotorheads
18th Dec 2020, 18:53
Replies: 146
Views: 19,952
Posted By MeddlMoe

The lock number has very little influence on the...

The lock number has very little influence on the phase lag. (It is also not the delta 3 angle, as somebody else claimed)

The phase lag is predominantly determined by the flapping hinge offset....
Forum: Rotorheads
18th Dec 2020, 11:46
Replies: 146
Views: 19,952
Posted By MeddlMoe

This is not correct. The Lock number has very...

This is not correct. The Lock number has very little to do with it.

The critical parameter for the phase shift is the relative flapping hinge offset. This is the ratio between the distance of the...
Forum: Rotorheads
17th Dec 2020, 09:33
Replies: 146
Views: 19,952
Posted By MeddlMoe

I think here is a fundamental misunderstanding by...

I think here is a fundamental misunderstanding by some of you:

The coriolis effect, gyroscopic effect, and centrifugal force are not some kind of "extra physics" or "magical effects" that occur on...
Forum: Rotorheads
15th Dec 2020, 17:37
Replies: 146
Views: 19,952
Posted By MeddlMoe

Of course I did not consider the roation of the...

Of course I did not consider the roation of the earth (indeed negledible for a helicopter rotor), but the rotation of the rotor.

The Coriolis force appears in a rotating coordinate system when...
Forum: Rotorheads
15th Dec 2020, 08:35
Replies: 146
Views: 19,952
Posted By MeddlMoe

The rotor blades are often analyzed in a...

The rotor blades are often analyzed in a coordinates system that rotates with the rotor blade, has its origin in the rotor center, and a primary axis parallel to the (coned) pitch axis. In this...
Forum: Rotorheads
14th Dec 2020, 16:49
Replies: 30
Views: 17,169
Posted By MeddlMoe

Vibrations on a flex beam rotor

Congratulations! :D

I am surprised by the low vibration levels on a flexbeam rotor. Is it only an improvement over the old 2-blade rotor, or is the vibration level even low compared to other...
Showing results 1 to 34 of 34


 
Forum Jump

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information

Copyright © 2022 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.