EC145
Joined: May 1999
Posts: 101
Likes: 0
From: UK
Thanks Nick, it now starts to make sense, with the formula for stored energy and 212 man's explanation. Wouldn't it be nice if the manufacturer's put a little bit of background information in the systems description of the aircraft flight manual?
Joined: Mar 2003
Posts: 573
Likes: 0
From: uk
I congratulate all those who have responded to this subject. Your inputs are informative and constructive and it would surely benefit the readers of the manuals if the explanation were provided of the particular system, but in a stand alone annex, not in the main text. The main text needs to be precise and to the point and not painted with extra explanations as is the system at the present time.
Thank you all.
Thank you all.
Joined: Jul 2006
Posts: 59
Likes: 0
From: Greater Dubach Metro Area
EC145 Tail Rotor RPM
Anyone know the tail rotor RPM of the EC145 ... or at least the ratio of the main to tail rotor? I've been trolling the web, manuals, etc and can't find anything that indicates this. Thanks for your help!
Tompkins
Tompkins
Joined: Aug 2005
Posts: 313
Likes: 0
From: West Africa
As I understand it , the ratio is usually 6-1.
That is 6 rotations of the tail rotor for every 1 rotation of the main rotor, but I am not sure if that is the case for all helo's.
For the Notars.....erm ?????
Does anyone know of any helos where this is not the case... 6-1 rule?
HF
That is 6 rotations of the tail rotor for every 1 rotation of the main rotor, but I am not sure if that is the case for all helo's.
For the Notars.....erm ?????
Does anyone know of any helos where this is not the case... 6-1 rule?
HF
Joined: Apr 2003
Posts: 3,012
Likes: 1
From: USA
HELOFAN,
There really is no rule about ratios of rpm, but many times the tail rotor tip speed is the same as the main rotor (when a conventional open tail rotor is used), so the ratio of the rpm is often the ratio of the diameters of the two rotors. Many rotors use a tip speed between 700 and 725 feet per second. For the EC-145 that turns out to be a 6.5 to 1 rpm ratio.
There really is no rule about ratios of rpm, but many times the tail rotor tip speed is the same as the main rotor (when a conventional open tail rotor is used), so the ratio of the rpm is often the ratio of the diameters of the two rotors. Many rotors use a tip speed between 700 and 725 feet per second. For the EC-145 that turns out to be a 6.5 to 1 rpm ratio.
Joined: Aug 2005
Posts: 313
Likes: 0
From: West Africa
Thanks Nick.
I should say that the word "rule" was a term I was using loosly and should have said average is around.
Do you know where the ration of about 6-1 isnt correct?
I was thinking for multi tail rotor helo's such as the Apache or possibly the larger or smaller helo's come into play.
I would think it should not matter but I had to ask.
Thanks again.
HF
I should say that the word "rule" was a term I was using loosly and should have said average is around.
Do you know where the ration of about 6-1 isnt correct?
I was thinking for multi tail rotor helo's such as the Apache or possibly the larger or smaller helo's come into play.
I would think it should not matter but I had to ask.
Thanks again.
HF
Joined: Jul 2002
Posts: 503
Likes: 0
From: mostly in the jungle...
EC145 - anyone?
Hi all,
it seems the used-market for the EC145 is bone-dry.
I am looking for a EC145 ASAP, pref. in Utility config. but will consider any machine as long as special equipment does not make the deal economically un-acceptable....
Please send me a Private Message....
Cheers,
3top
it seems the used-market for the EC145 is bone-dry.
I am looking for a EC145 ASAP, pref. in Utility config. but will consider any machine as long as special equipment does not make the deal economically un-acceptable....
Please send me a Private Message....
Cheers,
3top
Joined: Jul 2004
Posts: 146
Likes: 1
From: Huntsville AL
Well how about that we already have a EC145 thread...guess we just need to get it back to the top!
Svenestron, the Apache has a stacked tail rotor. It is basically two two bladed systems stacked with about 6 inches or so in between for noise reasons. If you have ever heard one nearby you would agree it works!
Max
Svenestron, the Apache has a stacked tail rotor. It is basically two two bladed systems stacked with about 6 inches or so in between for noise reasons. If you have ever heard one nearby you would agree it works!
Max
Joined: Jul 1999
Posts: 3,931
Likes: 142
From: Warrington, UK
Svenestron, the Apache has a stacked tail rotor. It is basically two two bladed systems stacked with about 6 inches or so in between for noise reasons.
Joined: Jul 2004
Posts: 146
Likes: 1
From: Huntsville AL
Svenestron,
Yes I believe it is to reduce the interaction between the tip vorticies but it has been a looooong time since I went to school on that machine so I wouldn't swear it to be true. I can say that the sound is much lower frequency and amounts to a low hum, much quieter than the unit on the blackhawk which is about the same size aircraft. Not only are they space apart axially but they have an odd phase angle separation (the blades are not all 90 degrees apart). This may have as much to do with the low noise as anything else.
I'll be interested to see if the B model EC145, whenever it comes, will have the fenestron tail on it. I don't think the machine has much of an issue with tr performance as it is so any change to the fenestron would most likely be for noise reasons only.
Max
Yes I believe it is to reduce the interaction between the tip vorticies but it has been a looooong time since I went to school on that machine so I wouldn't swear it to be true. I can say that the sound is much lower frequency and amounts to a low hum, much quieter than the unit on the blackhawk which is about the same size aircraft. Not only are they space apart axially but they have an odd phase angle separation (the blades are not all 90 degrees apart). This may have as much to do with the low noise as anything else.
I'll be interested to see if the B model EC145, whenever it comes, will have the fenestron tail on it. I don't think the machine has much of an issue with tr performance as it is so any change to the fenestron would most likely be for noise reasons only.
Max
