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Search: Posts Made By: NickLappos
Showing results 1 to 35 of 1000
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Forum: Rotorheads
12th Jul 2021, 03:55
Replies: 11
Views: 2,427
Posted By NickLappos

Tip Rocket, Tip Jet

The Rotordyne had rotor tip ram jet thrusters fed fuel along the blades. The Hughes H 17 (https://en.wikipedia.org/wiki/Hughes_XH-17) used tip jets that were fed air from engines on the fuselage. I...
Forum: Rotorheads
12th Jul 2021, 03:55
Replies: 19
Views: 6,082
Posted By NickLappos

Tip Rocket, Tip Jet

The Rotordyne had rotor tip ram jet thrusters fed fuel along the blades. The Hughes H 17 (https://en.wikipedia.org/wiki/Hughes_XH-17) used tip jets that were fed air from engines on the fuselage. I...
Forum: Rotorheads
28th Jul 2018, 18:11
Replies: 1,327
Views: 374,031
Posted By NickLappos

That is one way to describe it donut king (love...

That is one way to describe it donut king (love the name!), but it is easiest to see it as the fact that with higher tip speed at higher Nr, the retreating tips are quite a bit less stalled (yes,...
Forum: Rotorheads
18th Jul 2018, 04:02
Replies: 1,327
Views: 374,031
Posted By NickLappos

76 RPM

The original S76A had an rpm range in powered flight from 96% to 107%. This allow the pilot to select the RPM based on flight condition and the optimal performance. Some information was provided to...
Forum: Rotorheads
18th Aug 2017, 21:25
Replies: 1,327
Views: 374,031
Posted By NickLappos

TIMTS That doesn't have a grain of truth to it!...

TIMTS
That doesn't have a grain of truth to it! The Vne is a complex limit, because once it is established, then many calculations about dynamic system life are made from the flight loads at Vne...
Forum: Rotorheads
18th Aug 2017, 18:42
Replies: 9
Views: 3,550
Posted By NickLappos

BP Downdraft Video

worth a watch, forgive me if it has made the rounds. And thanks to any Ppruners who made this it is brilliant.

09bvuYRKwwc
Forum: Rotorheads
29th Jul 2017, 19:06
Replies: 32
Views: 10,961
Posted By NickLappos

Wiggins61 is right, on all counts. The grease...

Wiggins61 is right, on all counts. The grease lubed roller or ball bearings can get to about 250 to 300 degrees and still be very happy. The limit, based on the type of grease used, can be a...
Forum: Rotorheads
21st Jul 2017, 16:42
Replies: 24
Views: 6,640
Posted By NickLappos

Re: Controlled airspace. In the US the airspace...

Re: Controlled airspace. In the US the airspace is "controlled" in that the operations might be under ATC approval, esp in IMC, but otherwise (VMC)everybody can enter and use it without ATC...
Forum: Rotorheads
15th Jul 2017, 21:36
Replies: 53
Views: 16,958
Posted By NickLappos

I wrote this a few years back, it uses less...

I wrote this a few years back, it uses less oldeth English but tells what the ten best rules to handle an emergency are:

One – fly the aircraft, do not let it fly you. A crippled aircraft is still...
Forum: Rotorheads
14th Jul 2017, 14:17
Replies: 17
Views: 4,108
Posted By NickLappos

Here is a very detailed FAA document with lots of...

Here is a very detailed FAA document with lots of data. It is "Rotorwash Analysis Handbook" FAA AD A283 719:

http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA283719&Location=U2&doc=GetTRDoc.pdf
Forum: Rotorheads
11th Jul 2017, 14:17
Replies: 24
Views: 6,640
Posted By NickLappos

JimL said: "However, the majority of unprepared...

JimL said: "However, the majority of unprepared sites are in 'uncontrolled airspace'; for that reason the safe use of 'let down' procedures will be dependent upon the effective use of 'detect and...
Forum: Rotorheads
10th Jul 2017, 00:14
Replies: 156
Views: 73,193
Posted By NickLappos

It costs too much? Wow, let's take an example: ...

It costs too much? Wow, let's take an example:
the US EMS industry uses about 850 helicopters. It has about 8 fatal crashes a year. Hmmmm, that's 1% of the fleet.
If a fatality costs about 10...
Forum: Rotorheads
9th Jul 2017, 19:31
Replies: 156
Views: 73,193
Posted By NickLappos

alphanumeric, you are right, but if they cannot...

alphanumeric, you are right, but if they cannot fly IFR on their job, they are effectively Robinsons. The need is for helicopter approaches to heliports, helicopter routes and the equipment.
...
Forum: Rotorheads
9th Jul 2017, 18:11
Replies: 24
Views: 6,640
Posted By NickLappos

Driving on the Planet Mongo

Printed in HeliOps magazine circa 2007:

The IHST’s Challenge The FAA and the HAI have joined forces to form a safety team to reduce helicopter accidents by 80% in 10 years. Their efforts to date...
Forum: Rotorheads
9th Jul 2017, 18:08
Replies: 156
Views: 73,193
Posted By NickLappos

Time to weigh in on this: 1) Airplanes...

Time to weigh in on this:

1) Airplanes passed through this same Mayhem-by-Air phase in the late 1920's, when crashes due to CFIT were more common than any other cause. Mandatory routes, IFR...
Forum: Rotorheads
8th Jul 2017, 03:32
Replies: 5
Views: 3,175
Posted By NickLappos

Tickle, It is more than the rear of a Dauphin,...

Tickle,
It is more than the rear of a Dauphin, it has the same transmission, rotor head and blades. Basically it is an AS155/ Z-9 with a skinny fuselage. It has the Chinese version of the Arriel...
Forum: Rotorheads
28th Jun 2017, 02:05
Replies: 44
Views: 20,379
Posted By NickLappos

Good on you, 212man! The PBA did help that case,...

Good on you, 212man! The PBA did help that case, its contribution was included in the comment I made. The stroke of that Pitch Bias Actuator was not quite enough to fully cancel out the effects of...
Forum: Rotorheads
27th Jun 2017, 22:04
Replies: 44
Views: 20,379
Posted By NickLappos

I wrote the Vne Auto chart for the S-76! It is a...

I wrote the Vne Auto chart for the S-76! It is a fine story in itself, and I think it illustrates the randomness of Vne determination.

The FAA requires that you must have Longitudinal Static...
Forum: Rotorheads
27th Jun 2017, 16:18
Replies: 44
Views: 20,379
Posted By NickLappos

John Dixson is absolutely correct, in the...

John Dixson is absolutely correct, in the Sikorsky Test Pilot Office, the stock answer to any question was either:


1) Six knots per thousand
2) Hot and Dusty
3) All we really did was dance....
Forum: Rotorheads
26th Jun 2017, 19:34
Replies: 44
Views: 20,379
Posted By NickLappos

Vne is set during the design and test phase, and...

Vne is set during the design and test phase, and is the result of a mix of possible things. There is no reason why a manufacturer has to go to a limit to make a Vne, it could be just where they...
Forum: Rotorheads
7th Jun 2017, 01:15
Replies: 33
Views: 8,693
Posted By NickLappos

thanks Reely340 for so clearly stating the...

thanks Reely340 for so clearly stating the question!


What I am stating is that in c below, the application of original power of 80% will not steady the descent, because in a slight descent of...
Forum: Rotorheads
6th Jun 2017, 17:07
Replies: 33
Views: 8,693
Posted By NickLappos

albatross, I think the explanation is that it...

albatross,
I think the explanation is that it entered Power Settling and then degraded to VRS as the power-induced descent increased. The terrible thing about rotors is that as you go from a stable...
Forum: Rotorheads
6th Jun 2017, 02:28
Replies: 33
Views: 8,693
Posted By NickLappos

megan, That is a good system, I used to teach a...

megan,
That is a good system, I used to teach a similar one, what you are doing is estimating the shape of the power required curve from the Vx to the OGE power. The ratio is probably about 2x, with...
Forum: Rotorheads
5th Jun 2017, 21:29
Replies: 33
Views: 8,693
Posted By NickLappos

Hughes500 is quite right There is far too much...

Hughes500 is quite right
There is far too much worry about Vortex Ring State and not nearly enough about avoiding entering OGE conditions with too little power margin. The number of real VRS...
Forum: Rotorheads
2nd Jun 2017, 18:45
Replies: 1,327
Views: 374,031
Posted By NickLappos

riff_raff is right, there is a minimum fuel flow...

riff_raff is right, there is a minimum fuel flow for an engine that dictates how quickly it can slow down in normal circumstances. This min fuel flow is what we see when we drop collective rapidly,...
Forum: Rotorheads
28th May 2017, 20:33
Replies: 1,327
Views: 374,031
Posted By NickLappos

Aircraft lore is made of these kind of questions!...

Aircraft lore is made of these kind of questions!
For all S-76 models:
1) The tail rotor is driven by the main bull gear, and thus by either engine.
2) It is not possible to isolate the TR drive...
Forum: Rotorheads
3rd Apr 2017, 18:48
Replies: 8
Views: 4,460
Posted By NickLappos

It is bad form to make direct negative reference,...

It is bad form to make direct negative reference, otherwise I'd look like HC!

Seriously, the ability to have some excess yaw control is important, and should not be lightly tossed away. The...
Forum: Rotorheads
1st Apr 2017, 19:03
Replies: 8
Views: 4,460
Posted By NickLappos

In FAA Part 29 manuals, the maximum operating...

In FAA Part 29 manuals, the maximum operating weight for the type of operation (Cat A or B) is expressed in the WAT curve, the weight, Altitude and Temperature that defines the max operating weight....
Forum: Rotorheads
19th Mar 2017, 23:51
Replies: 21
Views: 4,631
Posted By NickLappos

Simply said, Vortex Ring State is the condition...

Simply said, Vortex Ring State is the condition that occurs when the rotor is descending into its own down wash. In autorotation, the rotor is descending far faster than that, so that there is no...
Forum: Rotorheads
21st Feb 2017, 17:43
Replies: 58
Views: 10,066
Posted By NickLappos

It is fun reading all the wishes, especially...

It is fun reading all the wishes, especially having participated in the design of perhaps 15 aircraft. The real issue for us all it to recognize the physics of the situation. Making metal fly is not...
Forum: Rotorheads
10th Jan 2017, 20:02
Replies: 8
Views: 2,635
Posted By NickLappos

Andrew, I had the pleasure of working with your...

Andrew,
I had the pleasure of working with your Dad, and Alistair Gordon (and Alan Bristow) during the S-61 and early S-76A days. He was the consummate professional, and as sharp as can be in all...
Forum: Rotorheads
22nd Dec 2016, 23:28
Replies: 23
Views: 5,662
Posted By NickLappos

AnFI, what is your problem?

AnFI, what is your problem?
Forum: Rotorheads
22nd Dec 2016, 22:26
Replies: 23
Views: 5,662
Posted By NickLappos

In an attempt to keep this thread purely...

In an attempt to keep this thread purely technical, let me try to explain how I see the vertical undersling's function. I believe the larger that undersling the worse the 1/rev vibration of the...
Forum: Rotorheads
22nd Dec 2016, 06:02
Replies: 23
Views: 5,662
Posted By NickLappos

A true teetering rotor has zero hinge offset. It...

A true teetering rotor has zero hinge offset. It produces no head moment if there is no positive thrust on the rotor (thus the worries about zero g maneuvers).
Forum: Rotorheads
29th Nov 2016, 23:58
Replies: 69
Views: 12,056
Posted By NickLappos

48 years, and counting. Wouldn't swap a day of it.

48 years, and counting. Wouldn't swap a day of it.
Showing results 1 to 35 of 1000
 
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