ariis
Posts: 387
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Canadair CRJ-200 Rocks

Wed Sep 22, 2004 11:21 pm

Hello all,

I recently flew on Canadair CRJ-200 for the first time and after the plane reached its cruising altitude and started flying straight and level, I still had this strange feeling that something was unsteady and the plane was still turning or something, although everything seemed quite normal.

Then, when I looked at the opposite window (I was sitting by the window myself), I saw the horizon moving slowly from the top edge of that window to the bottom edge in an about 10 seconds cycle. The airplane kept rocking this way for the entire 1.5 hours flight and I felt like I was on a ship or something.

I am not familiar with regional (read: small) jets and by curiosity I want to ask: is it normal, that the plane cannot stabilize and keeps slightly banking left and right for a longer period of time? I believe it is the computer or the auto-pilot, that keeps the heading and bank angle most of the time. Perhaps something wrong with the left-right engine thrust stabilization caused this? I don't know.

If you ask me I would say that in synchronization with the plane rocking, I could hear a really slight change in the engine sound (like slightly louder-quieter-louder-quieter...), but that could just be me.

Thank you in advance
FAO
FAO - Flight Activities Officer
 
FinnWings
Posts: 633
Joined: Fri Oct 24, 2003 6:03 am

RE: Canadair CRJ-200 Rocks

Wed Sep 22, 2004 11:41 pm

Well, most likely it was just a strong jetstream on your route. Wind speed in a jetstream is usually around 100-150kts (50-70ms/s). That might explain the constantly changing power setting on engines as the pilot or auto-throttle tried to keep constant speed which was disturbed by the wind. This is normal for all sized airlines, I have experienced same on B747 as well.

Best Regards,
FinnWings
 
saab2000
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RE: Canadair CRJ-200 Rocks

Thu Sep 23, 2004 2:20 am

I have now got about 200 hours logged on the CRJ-200 with Air Wisconsin. I have noticed both things you mention. We have no autothrottle on our airplanes, and we also don't have the engine speed synchronization option which is apparently available. We have to sync them ourselves, which is not too hard. This cuts down on the pitch/tone oscillations you hear.

Also, yes, the slight roll you noticed is real. I guess because of the wing design there is a slight tendancy for dutch roll to develop. The yaw damper in this airplane is, IMHO, not very good at controlling it and indeed, there is less of a rock solid feel to the autopilot flying.

I was especially surprised to find out in the simulator that the rudder is not fully coupled to the autopilot, meaning that it is very easy to fly uncoordinated if there is not a lot of care taken with the rudder.

Yes, it rocks and rolls. But less than the ERJ if you ask me.
smrtrthnu
 
ariis
Posts: 387
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RE: Canadair CRJ-200 Rocks

Thu Sep 23, 2004 7:25 am

Hi there,

thank you for your great explanations.

I consider myself above average in terms of the number of flights I took so far (at least in the country I live in), but have never come across such a rocking plane. Interesting experience though.

Thanks a lot again & best regards
FAO
FAO - Flight Activities Officer
 
airplay
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RE: Canadair CRJ-200 Rocks

Thu Sep 23, 2004 10:16 am

In my experience, dutch roll is quite pronounced on small high performance airplanes regardless of model compared to larger aircraft.

Fokker had to deal with the issue quite agressively when they introduced their relatively small F-28.

Frankly I don't know why this is (I'm no aerodynamics guru) but I pretty much expect it on smaller jets.
 
DeltaGuy
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RE: Canadair CRJ-200 Rocks

Thu Sep 23, 2004 10:19 am

Yes, it rocks and rolls. But less than the ERJ if you ask me.

Anything's better than those ERJ deathtraps...rode one once, never again.

DeltaGuy
"The cockpit, what is it?" "It's the little room in the front of the plane where the pilot sits, but that's not importan
 
airplay
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RE: Canadair CRJ-200 Rocks

Thu Sep 23, 2004 10:40 am

DeltaGuy,

I've only ever been on an ERJ once, and even though I am biased towards the CRJ (being Canadian and all) I didn't remember it as an unpleasant ride.

It was a little noisier and since I was at the very back, looking down the long aisle on approach made me fell a little queasy (and I NEVER get airsick) but otherwise it was a nice ride.

After close ground inspection of both types, I think the CRJ is built better considering both design and craftsmanship though..

Do what exactly turned you off about the ERJ? (Besides the pictures that showed a 135 broken in half after a hard landing)
 
saab2000
Posts: 1216
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RE: Canadair CRJ-200 Rocks

Thu Sep 23, 2004 10:49 am

The ERJ is not a bad plane. I have ridden on one several times, both in back and in the flight deck jumpseat. I have heard from some who say it is not as well built as the CRJ and this may be true, but I am not a mechanic or engineer and cannot make that judgement.

I will say this: The CRJ is underpowered. We are certified to FL410 and mach .84. I have only once seen FL390 on an empty flight and only seen mach .80 in descent. When we are full, we struggle to reach FL310 and the cruise is about .76-.78. Those are not bad numbers, but the plane could use about 1000 lbs more thrust per side. Also, the cabin is a bit claustrophobic.

I have heard, though, that the 700 series fixes most of the issues with the 200. I would really like to fly the CRJ-700. Not only does it have better performance, it looks super! Big grin
smrtrthnu
 
FinnWings
Posts: 633
Joined: Fri Oct 24, 2003 6:03 am

RE: Canadair CRJ-200 Rocks

Thu Sep 23, 2004 7:50 pm

Saab2000,

Thanks for your good explanations. I didn't know that CRJ has such a strong tendency for dutch roll. Actually I have heard that many smaller general aviation aircrafts are sensitive with this (like Beechcraft Bonanza and Piper Seneca) but I didn't know that some bigger aircrafts has the same problem as well. My thoughts earlier about jetstream were obviously only a bad guess this time... Big grin

I suppose this dutch roll tendency of CRJ200 is caused by a relatively small vertical stabilizer and short fuselage, right? I'm wondering has Canadair tried to fix this tendency as it must effect to fuel consumption due the increased drag in cruise?

Best Regards,
FinnWings
 
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Starlionblue
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Joined: Fri Feb 27, 2004 9:54 pm

RE: Canadair CRJ-200 Rocks

Thu Sep 23, 2004 8:01 pm

The MD-8x has the same tendency, but in pitch. I have had the experience several times in SAS planes. Just a slight rocking back and forth about 4-5 seconds in period. Talked to a few pilots. They say it happens. They switch AP off, retrim, switch on, switch off, retrim, switch on, and in the end give up!
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
AC_A340
Posts: 2196
Joined: Wed Sep 08, 1999 12:01 pm

RE: Canadair CRJ-200 Rocks

Thu Oct 14, 2004 5:52 am

I have some time experience in a CRJ trainer, it could've been something as simple as the autopilot adjusting to stay on course. And the yaw dampers do indeed seem inadequate at times. The jet stream explanation is also very possible.
 
GroundStop
Posts: 607
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RE: Canadair CRJ-200 Rocks

Thu Oct 14, 2004 7:48 am

Hey SAAB,

Where are you based with AirWis? I have some good friends (and one great girl) who were based in ATL with the JetConnect operation and are now mostly flying out of IAD.

JP
 
XFSUgimpLB41X
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RE: Canadair CRJ-200 Rocks

Thu Oct 14, 2004 9:27 am

The plane always wiggles around a bit... the autopilot isnt a very smooth one. The yaw damper isn't worth crap either..it stops the dutch roll to an extent, but you still have to use the rudder when making turns..the plane will just sit there and fly uncoordinated.

Main thing with the wings rocking around is that's just the autopilot. It's not smooth- the plane always flies smoother and does things smoother with someone hand flying it (unless they aren't a good stick, haha).
Chicks dig winglets.
 
DeltaGuy
Posts: 3965
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RE: Canadair CRJ-200 Rocks

Thu Oct 14, 2004 1:06 pm

Do what exactly turned you off about the ERJ?

Well, OTHER than that photo...it was an extremely uncomfortable cabin (despite the 2-1 seating), and I just had this feeling that I was on an old EMB-120..rickety and made of the same construction as it's turboprop dad. Something I never want to do again. Canadair makes a much better regional product, in my opinion.

DeltaGuy
"The cockpit, what is it?" "It's the little room in the front of the plane where the pilot sits, but that's not importan
 
UAL Bagsmasher
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RE: Saab2000

Fri Oct 15, 2004 6:43 am

Stop by the ORD hangar some night and say hi!
 
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Bruce
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RE: Canadair CRJ-200 Rocks

Fri Oct 15, 2004 8:31 am

I agree, the -700 looks better. Though I've never flown on one. But I have flown on the 100/200 most recently in August (4 legs). I hate the CRJ. Very uncomfortable, BAD placement of the windows (too low) and cramped also.

I also flew on an ERJ last month, and it was more comfortable. The single seat on the left doesnt bother me. And its mighty quiet too.

Perhaps the CRJ is underpowered because in the design phase those engines were chosen, because the launch customer was Comair and they use 'em on short segments where they dont need FL400 and higher speed. It has been said that Comair really beats the heck out of those CRJ's with such short and frequent segments.

bruce
Bruce Leibowitz - Jackson, MS (KJAN) - Canon 50D/100-400L IS lens
 
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Francoflier
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RE: Canadair CRJ-200 Rocks

Fri Oct 15, 2004 11:09 am

Don't all tail engined aircraft suffer from that dutch roll tendency to an extent?

I mean the combination of having wings close the the vertical stabilizer really doesn't help, does it?
I'll do my own airline. With Blackjack. And hookers. In fact, forget the airline.
 
KALB
Posts: 564
Joined: Sat Mar 11, 2000 12:33 pm

RE: Canadair CRJ-200 Rocks

Fri Oct 15, 2004 10:44 pm

Believe it or not, but Microsoft FS 2002 simulates the dutch roll very well in the Lear 45, and for the CRJ 200 and MD-88 add-ons I have. Very frustrating to try to correct.
 
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rg828
Posts: 568
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RE: Canadair CRJ-200 Rocks

Sat Oct 16, 2004 11:31 am

I've experienced the slight rolling on most airliners - big and small - as well, always wondered what the devil made the plane do that in level, smooth flight.

I assumed it was the AP trying to control some minor dutch-rolling.

Tha last time I saw this was on a Boeing 763.
I dont know the key to success, but the key to failure is trying to please everyone
 
cannikin
Posts: 79
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RE: Canadair CRJ-200 Rocks

Fri Oct 29, 2004 10:20 pm

"Do what exactly turned you off about the ERJ? (Besides the pictures that showed a 135 broken in half after a hard landing)"



Whoa!!! Where can I find this pic? Didnt see it in the A.net Dbase.


I prefer the ERC over the CRJ in the looks dept, but I've never travelled on the ERJ, so I cant speak on that point. My only RJ experience was a Pinnacle flight from LIT-MEM-TUL. I was ammused at the small size...Even had to stow my CARRY ON in the hold! hehe. The overhead bins were smaller than the glove box in my Intrepid!
 
Qb001
Posts: 1923
Joined: Fri Apr 28, 2000 12:42 am

RE: Canadair CRJ-200 Rocks

Sun Oct 31, 2004 5:51 am

Sorry if I ask a dumb question, but may this "dutch roll effect" explain why Lear felt it had to add the strange inverted-V thing under the tail of some of their aircraft ?


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