3 Engined Falcons

Frank Rome · April 17th, 2006, 17:18

Hello all,

This post may belong in the technical QA's section, but I figure a couple Falcon drivers out there may be able to shed more light on this topic.

I worked line service at a rather busy FBO in Atlanta for 3 years and one thing always caught my eye about Falcons. I am curious as to why on the FA50, F900, and FA7X Dassault only put a thrust reverser on the center engine and not on the #1 and #3 engines. I have read that certain aircraft have issues with reverse thrust on rear (fuselage) mounted engines causing buffeting and reduced control effectiveness.
However, on the F2TH they used the reversers on the fuselage mounted engines and the stablizer appears to be in the same place as on the 900. So it would seem that this is not the reason. Why wouldn't they have these reversers installed on the three engined Falcons as well? Wouldn't having 3 usable reversers create more efficient stopping power?

Thank you in advance for all your insight gentlemen.

FR

jonnyb · April 17th, 2006, 19:35

I don't fly a Falcon, but my first thought would be because they don't need them. Falcon's have relatively slow approach speeds and good brakes; I don't think they need additional reversers. They would add more weight, more moving parts etc. I think Dassault just deemed them unecessary. Just an observation though. I'm sure a Falcon pilot could shed some additional light on the subject.

JDE · April 17th, 2006, 22:02

jonnyb is right when he says Falcon's have low Vref speeds. The 50 for example typically has a Vref speed of 106 and can land in less than 3000' at max gross landing weight. The 900's typical Vref speed is 109 and can land in just over 3500' at max gross weight. (Taken from the Dassault website). Now, as far as only having 1 reverser, I would guess that just as jonnyb said, they just don't need them. Also, I looked through the 900B manual and if you notice, the reverser reverses the exhaust in a horizontal stream...so I have to think that the exhaust from the #2 engine is somewhat disrupting the exhaust flow out of #1 and #3 engines. I'm not sure how much effect this has, but it's a thought.

falconvalley · April 18th, 2006, 01:45

My dad flies a 900, I'll ask him. He's said that they barely use the available thrust on the reverser.

I've heard that some airplanes with rear-mounted fuselage engines have limitations on reverse thrust because of rudder control. I don't know the details, though. The final report of the MD-80 that went off the end of the runway at KLIT mentioned directional control at max reverse thrust.

Tim · April 18th, 2006, 02:06

I remember when it came out that the -88 had to have the nose on the ground before deploying reversers. I think they were having some tail strikes doing it the other way like it was a DC-9.

Bandit_Driver · April 18th, 2006, 08:13

The 727 has 3 reversers but the nose wheel should be on the ground first or you risk setting the bird on its tail.

I do believe one of the smaller CRJ's or ERJ's did have a problem with reverse thrust shaking the tail

n57flyguy · April 18th, 2006, 08:46

Yeah, you guys got it. Falcons have excellent braking and slower approach speeds as metioned. One center thrust reverser is really all it needs and it provides more control on the landing roll, all said before me. There was a pretty good artical in Flying magazine about the newest 900DX and the thrust reverser issue was brought up. However, I still dont know why that 900 overan the runway at KTEB.

Frank Rome · April 18th, 2006, 16:16

Thanks so much for the info guys. I didn't even consider how low their ref speeds are. It also makes a lot of sense that the sideways vector of the #2 reverser would disrupt the other engines thrust. I guess that's kind of like the paddles that Cessna used on the CJ. It's all starting to make sense now. I appreciate the help everybody.

FR

falconvalley · April 19th, 2006, 00:09

Quote:

Originally Posted by n57flyguy

Yeah, you guys got it. Falcons have excellent braking and slower approach speeds as metioned. One center thrust reverser is really all it needs and it provides more control on the landing roll, all said before me. There was a pretty good artical in Flying magazine about the newest 900DX and the thrust reverser issue was brought up. However, I still dont know why that 900 overan the runway at KTEB.

When did that happen?

Casper · April 19th, 2006, 23:31

tis true...i had a discussion with the Director of Operations in our company a while back when we started talking about the 50 and the possiblity of getting it when we got rid of the 20.

The DLE's are the key, and the brakes are great...they ahve to be. Dassault builds tanks with wings.

falconvalley · April 19th, 2006, 23:39

Quote:

Originally Posted by Casper

Dassault builds tanks with wings.

Yeah they do. Tanks that fly like fighters.

Casper · April 20th, 2006, 01:56

its amazing how that works...when i went from the Falcon to the citation I was like, where did all the handling go?

n57flyguy · April 20th, 2006, 09:14

Quote:

Originally Posted by falconvalley

When did that happen?

About two months ago. I dont think NTSB has released much yet. My friend who works there told me. First a Callenger 300 overran about a year before then a 900 recently. He had a tail wind on 24 then was able to land on 6. I really dont know much though, Ill do some research.

AlexF · April 20th, 2006, 23:50

Quote:

Originally Posted by n57flyguy

About two months ago. I dont think NTSB has released much yet. My friend who works there told me. First a Callenger 300 overran about a year before then a 900 recently. He had a tail wind on 24 then was able to land on 6. I really dont know much though, Ill do some research.

They only released the prelim info, but here that is just incase your curious:
http://www.ntsb.gov/ntsb/brief.asp?e...15X00308&key=1

n57flyguy · April 21st, 2006, 06:45

Quote:

Originally Posted by AlexF

They only released the prelim info, but here that is just incase your curious:
http://www.ntsb.gov/ntsb/brief.asp?e...15X00308&key=1

Alright, thanks.

April 18th, 2006, 01:45	#4
falconvalley Old Skool Join Date: Jan 2006 Location: KMKE Posts: 1,960	My dad flies a 900, I'll ask him. He's said that they barely use the available thrust on the reverser. I've heard that some airplanes with rear-mounted fuselage engines have limitations on reverse thrust because of rudder control. I don't know the details, though. The final report of the MD-80 that went off the end of the runway at KLIT mentioned directional control at max reverse thrust. __________________ British Airways flight asks for push back clearance from terminal. Control Tower replies: "And where is the world's most experienced airline going today without filing a flight plan?"

April 18th, 2006, 02:06	#5
Tim Old Skool Join Date: Apr 2003 Location: Atlanta Posts: 2,205	I remember when it came out that the -88 had to have the nose on the ground before deploying reversers. I think they were having some tail strikes doing it the other way like it was a DC-9. __________________ Once you have tasted flight, you will forever walk the earth with your eyes turn skyward, for there you have been, and there you will always long to return.----- Leonardo Da Vinci

April 18th, 2006, 08:13	#6
Bandit_Driver Old Skool Join Date: Oct 2003 Location: DTW Posts: 1,801	The 727 has 3 reversers but the nose wheel should be on the ground first or you risk setting the bird on its tail. I do believe one of the smaller CRJ's or ERJ's did have a problem with reverse thrust shaking the tail __________________ OOTSK Logbook Pro - Electronic Pilots Logbook

April 18th, 2006, 08:46	#7
n57flyguy Old Skool Join Date: Jan 2006 Location: Pennsylvania Posts: 3,771	Yeah, you guys got it. Falcons have excellent braking and slower approach speeds as metioned. One center thrust reverser is really all it needs and it provides more control on the landing roll, all said before me. There was a pretty good artical in Flying magazine about the newest 900DX and the thrust reverser issue was brought up. However, I still dont know why that 900 overan the runway at KTEB. __________________ -Paul It ain't always 65 and sunny

April 19th, 2006, 23:31	#10
Casper Junior Member Join Date: Oct 2005 Location: I dont care Posts: 194	tis true...i had a discussion with the Director of Operations in our company a while back when we started talking about the 50 and the possiblity of getting it when we got rid of the 20. The DLE's are the key, and the brakes are great...they ahve to be. Dassault builds tanks with wings. __________________ At the top of the food chain when you look below you, you see nothing but smiling faces, when you are at the bottom and look up....you see nothing but buttholes. DO328-300 IAI 1124 Westwind

April 17th, 2006, 17:18	#1
Frank Rome Newbie Join Date: Apr 2006 Posts: 2	3 Engined Falcons Hello all, This post may belong in the technical QA's section, but I figure a couple Falcon drivers out there may be able to shed more light on this topic. I worked line service at a rather busy FBO in Atlanta for 3 years and one thing always caught my eye about Falcons. I am curious as to why on the FA50, F900, and FA7X Dassault only put a thrust reverser on the center engine and not on the #1 and #3 engines. I have read that certain aircraft have issues with reverse thrust on rear (fuselage) mounted engines causing buffeting and reduced control effectiveness. However, on the F2TH they used the reversers on the fuselage mounted engines and the stablizer appears to be in the same place as on the 900. So it would seem that this is not the reason. Why wouldn't they have these reversers installed on the three engined Falcons as well? Wouldn't having 3 usable reversers create more efficient stopping power? Thank you in advance for all your insight gentlemen. FR

April 17th, 2006, 19:35	#2
jonnyb Senior Member Join Date: Apr 2001 Location: So. California Posts: 1,304	I don't fly a Falcon, but my first thought would be because they don't need them. Falcon's have relatively slow approach speeds and good brakes; I don't think they need additional reversers. They would add more weight, more moving parts etc. I think Dassault just deemed them unecessary. Just an observation though. I'm sure a Falcon pilot could shed some additional light on the subject.

April 17th, 2006, 22:02	#3
JDE Old Skool Join Date: Mar 2002 Location: Chattanooga, TN Posts: 1,568	jonnyb is right when he says Falcon's have low Vref speeds. The 50 for example typically has a Vref speed of 106 and can land in less than 3000' at max gross landing weight. The 900's typical Vref speed is 109 and can land in just over 3500' at max gross weight. (Taken from the Dassault website). Now, as far as only having 1 reverser, I would guess that just as jonnyb said, they just don't need them. Also, I looked through the 900B manual and if you notice, the reverser reverses the exhaust in a horizontal stream...so I have to think that the exhaust from the #2 engine is somewhat disrupting the exhaust flow out of #1 and #3 engines. I'm not sure how much effect this has, but it's a thought. __________________ Jason

April 18th, 2006, 16:16	#8
Frank Rome Newbie Join Date: Apr 2006 Posts: 2	Thanks so much for the info guys. I didn't even consider how low their ref speeds are. It also makes a lot of sense that the sideways vector of the #2 reverser would disrupt the other engines thrust. I guess that's kind of like the paddles that Cessna used on the CJ. It's all starting to make sense now. I appreciate the help everybody. FR

April 20th, 2006, 01:56	#12
Casper Junior Member Join Date: Oct 2005 Location: I dont care Posts: 194	its amazing how that works...when i went from the Falcon to the citation I was like, where did all the handling go? __________________ At the top of the food chain when you look below you, you see nothing but smiling faces, when you are at the bottom and look up....you see nothing but buttholes. DO328-300 IAI 1124 Westwind

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode