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Search: Posts Made By: delta3
Showing results 1 to 35 of 437
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Forum: Rotorheads
6th May 2012, 20:22
Replies: 137
Views: 25,721
Posted By delta3

Retreating blade stall

Fijdor,

Fully agree vibration is an early indicator
The stall in fact triggers a stable reaction of the rotor, the blow back tries to slow it down, resisting an "overspeed condition". Blow back...
Forum: Rotorheads
25th Apr 2012, 16:04
Replies: 7
Views: 3,087
Posted By delta3

I' am using since 2005 an own developed and very...

I' am using since 2005 an own developed and very complete navigation suite (2D, 3D, 2.5 D, tunnels, procedures , google synced, own terrain database, gyro and TAS integrated ( see elZee - Free...
Forum: Rotorheads
29th Feb 2012, 22:42
Replies: 23
Views: 7,692
Posted By delta3

Instructor

Aucky, check PM


d3
Forum: Rotorheads
18th Jan 2012, 13:07
Replies: 16
Views: 2,215
Posted By delta3

Stability

Crab

I can't publish a drawing right now, but the point I have trying to make (difficult apparently without a drawing) is that dynamic (un)stability depends mostly on geometry.

Picture a heli...
Forum: Rotorheads
17th Jan 2012, 20:54
Replies: 16
Views: 2,215
Posted By delta3

Low skids

EN48

You'r correct in stating that the low skid is statically more stable, but this has the reverse effect on dynamic stability:

the counter torque available from the rotor system remains the...
Forum: Rotorheads
16th Jan 2012, 10:13
Replies: 16
Views: 2,215
Posted By delta3

Dynamic roll over

crab


I agree with your practical comments, but:

I still don't like the reference because it should at least show first that the max cyclic counter angle is in all helis (I know of) smaller...
Forum: Rotorheads
13th Jan 2012, 21:40
Replies: 16
Views: 2,215
Posted By delta3

Dynamic roll

seafuryfan

The math, nor the scenario are correct.

Many articles that I checked on the reference you quote, are either wrong or incomplete, because the articles don't do the complete math, but...
Forum: Rotorheads
21st Dec 2011, 14:28
Replies: 14
Views: 3,896
Posted By delta3

DA and MR AUTO RPM

In auto rotation the angle of attack is (on average, forget for a moment the asymmetries of rotating blades) such that blade drag (plus some remaining gearbox torque=drag) needs to be compensated at...
Forum: Rotorheads
29th Sep 2011, 20:02
Replies: 23
Views: 7,692
Posted By delta3

I have the permit and can give you the name of a...

I have the permit and can give you the name of a licensed examiner.

The permit is about knowing the routes and demonstrating the steep landing procedures with one landing and take-off

Fly with...
Forum: Rotorheads
8th Aug 2011, 17:17
Replies: 317
Views: 57,148
Posted By delta3

Keeping VMC

Anfi: to apply your list one has to be in an armchair.

Why not keep it simpless as you proclaim yourself.

As been said before, stay in the middle of the clouds and the ground (vertical...
Forum: Rotorheads
5th Aug 2011, 14:45
Replies: 28
Views: 4,435
Posted By delta3

Anti Malaria

It probably depends how long you stay

If long, then you can do as the "Africans" say (ie no pil), but I noticed that most of them do get occasional fever attacks. Apparently suffices to forget...
Forum: Rotorheads
3rd Aug 2011, 18:09
Replies: 317
Views: 57,148
Posted By delta3

Anfi: "yup ... half way between the cloud...

Anfi:

"yup ... half way between the cloud and the ground at a speed that lets you stop before the cloud meets the ground
Some people cant see that."

I fully agreed with this seemingly...
Forum: Rotorheads
8th May 2011, 21:27
Replies: 29
Views: 13,160
Posted By delta3

Back to Sikorsky

Nick

Looking forward to see really new technology being tested and used.

Good luck.
Forum: Rotorheads
29th Apr 2011, 11:04
Replies: 37
Views: 6,028
Posted By delta3

Crab, bastOn

Gentlemen,

Perhaps you should take the time and the elementary politeness of reading what people say, before starting to jump on statements that were not there.

See previous post :

"Crab
...
Forum: Rotorheads
28th Apr 2011, 09:18
Replies: 37
Views: 6,028
Posted By delta3

Crab

Again you jump to the wrong conclusion.

Over and out.
Forum: Rotorheads
28th Apr 2011, 08:53
Replies: 37
Views: 6,028
Posted By delta3

Crab

Crab

Crab, yes it does.

It starts from basic physics, not from modelled behaviour, which makes it quite unique, but a formidably complex mathematical project (even including ground effect, tail...
Forum: Rotorheads
27th Apr 2011, 19:31
Replies: 5,672
Views: 4,591,029
Posted By delta3

Avoiding African Thunderstorm

http://www.pks.be/files/public/tunderstorm.JPG
Forum: Rotorheads
27th Apr 2011, 17:03
Replies: 1
Views: 877
Posted By delta3

EC 120 Rental in Kenya

Anybody knows an operator that has EC120 available in Kenya?

thx, d3
Forum: Rotorheads
27th Apr 2011, 16:47
Replies: 37
Views: 6,028
Posted By delta3

Crab

You are jumping a little fast to conclusions.

It pretend this is an advanced integrated simulator developped 6 years ago. (not really a humble statement, because I made it). It does very detailed...
Forum: Rotorheads
26th Apr 2011, 18:58
Replies: 37
Views: 6,028
Posted By delta3

Example of R44 dynamics

Levi

A very simple example :

R44, 2 POB, 140 liters, steady 50 feet hover, ISA.

Cyclic is at -2.15 degrees during this hover.
Pilot applies a step input to cyclic bringing and holding it...
Forum: Rotorheads
26th Apr 2011, 10:01
Replies: 37
Views: 6,028
Posted By delta3

Time lags cyclic control

Levi

Two main groups:

1. The rotor reaction time, depends on many parameters, but is in general very fast, typical 1 to 2 revolutions to execute the cyclic command. On a R44 that is approx...
Forum: Rotorheads
3rd Apr 2011, 09:22
Replies: 6
Views: 972
Posted By delta3

Back pain

One non US, non Military testimony:

5 years ago I developed pretty severe back pains. In part thanks to a previous thread here on PPRune, referring to previous military studies that Heli pilot are...
Forum: Rotorheads
11th Mar 2011, 20:09
Replies: 6
Views: 2,961
Posted By delta3

Frequencies

Coldreaction

I am afraid you pretty much answered your own question: MR-freq plus its higher order harmonics...

Most hull resonance frequencies will be below that frequency and certainly below...
Forum: Rotorheads
7th Mar 2011, 15:42
Replies: 12
Views: 4,259
Posted By delta3

Morocco

Look indeed at Helisud, new shareholders since 2008

Helisud Maroc: l'Historique de la compagnie Heliconia Aviation. (http://helicoptere.heliconia-maroc.com/helisud-maroc/)

Nice machines in...
Forum: Rotorheads
19th Feb 2011, 18:35
Replies: 431
Views: 203,774
Posted By delta3

Launch party

Of N-reg... ?

d3
Forum: Rotorheads
13th Feb 2011, 16:34
Replies: 5
Views: 1,376
Posted By delta3

Blowback

Stuck_in_an_ATR

There is a simple analytical formula for rotors that calculates the blow back. It boils down to:

Blow back is proportional to the coning angle
Blow back is proportional to the...
Forum: Rotorheads
1st Feb 2011, 21:44
Replies: 5,672
Views: 4,591,029
Posted By delta3

Albatross

This year a new nice hotel near Nyamagabe with helipad is build on the edge of the tropical rain forest just south of Gisovu

d3
Forum: Rotorheads
31st Jan 2011, 19:41
Replies: 5,672
Views: 4,591,029
Posted By delta3

Roundtrip Rwanda - Tanzania

http://www.pks.be/files/public/boats.JPG

Fishing boats lake Kivu - Rwanda

http://www.pks.be/files/public/tea_1.JPG

http://www.pks.be/files/public/tea_2.JPG

Tea growing Rwanda
Forum: Rotorheads
31st Jan 2011, 18:43
Replies: 392
Views: 86,466
Posted By delta3

Aucky, I kind of like the summary, only...

Aucky,

I kind of like the summary, only would refine :

Quote: "This perhaps turns into fully developed VRS if there is sufficient height for ROD to develop before ground contact, but even...
Forum: Rotorheads
4th Jan 2011, 22:31
Replies: 19
Views: 6,077
Posted By delta3

Dave

Quote from your link: "Musings on the single-blade rotor and 1P vibration."

This text indeed contains some of the scenario's of what can go wrong, first order oscillations in all directions.
...
Forum: Rotorheads
4th Jan 2011, 20:56
Replies: 19
Views: 6,077
Posted By delta3

Vibrations

Dave

The severe vibrations in cruise are produced by the different dynamic behaviors of the two different halves. These differences look nearly impossible to compensate in any reasonable dynamic...
Forum: Rotorheads
4th Jan 2011, 20:23
Replies: 19
Views: 6,077
Posted By delta3

Phil My concern is the total lack of...

Phil

My concern is the total lack of symmetry at the hub.

A stiff setup leads to big bending forces between an aerodynamically active blade and a basically dead weight that only sees inertial...
Forum: Rotorheads
4th Jan 2011, 18:47
Replies: 19
Views: 6,077
Posted By delta3

One blade

Adam

I think the BO-102 was a "hover training device"
I would be very doubtful it would be capable of achieving any speed.

As far as the construction would be:

flap : I can hardly see how a...
Forum: Rotorheads
3rd Jan 2011, 15:09
Replies: 28
Views: 14,163
Posted By delta3

B407 delta3

Helisphere

I finally got to do the math for the tail rotor and beware...

Any delta3 is better than no delta3 !
Negative delta3 can be better than positive !

In approximate numbers (for a...
Forum: Rotorheads
26th Dec 2010, 11:15
Replies: 28
Views: 14,163
Posted By delta3

B407 TR drawing

Helisphere

Not yet gotten hold of engineering drawings, only "artistic impressions" from maintenance manual, from which I made the following sketch:

http://www.pks.be/files/public/B407_TR.jpg
...
Showing results 1 to 35 of 437
 
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