please... need help with take off
06-09-2005 | 01:13 PM
#26
Senior Member
My Feedback: (4)
Joined: Jan 2005
Posts: 2,141
Likes: 0
Received 0 Likes
on
0 Posts
From: Madison, AL
RE: please... need help with take off
Bill,
I didn't think about that. I think the 11 incher will work for me. I hope it will, of course i have about 6 props now.
I didn't think about that. I think the 11 incher will work for me. I hope it will, of course i have about 6 props now.
06-09-2005 | 01:31 PM
#27
RE: please... need help with take off
A normal takeof (especially off grass) is usually not much above stall at a point when a plane really wants to accelerate to GOOD flying speed.
BTW Chad, I don't need your permission to PM or have anything to say that I am not willing to say right here. DO YOU?
Also BTW- did you know that under the right conditions a Lear jet stalls at over 500 MPH and the SR-71 can stall at speeds above mach 2? Still think speed is always the answer?
BTW Chad, I don't need your permission to PM or have anything to say that I am not willing to say right here. DO YOU?
Also BTW- did you know that under the right conditions a Lear jet stalls at over 500 MPH and the SR-71 can stall at speeds above mach 2? Still think speed is always the answer?
06-09-2005 | 02:36 PM
#28
My Feedback: (32)
RE: please... need help with take off
Chad,
I know you are taking Full Scale lessons so we will use that and assume you are in a Cessna 150 or bigger which will help explain what Bruce is talking about
Very early in your training you should have gone through stall training. You should know that a plane can be stalled at any airspeed. So knowing that, what actually is bringing on the stall? I will give you his much. yes speed has something to do with it but not in the example I am going to explain.
Angle of Attack (AOA) has everything to do with stall speed. Exceed that angle and the wing stalls. Exceed that angle in a turn and now you have one stalled wing and not the other. Guess what happens now, snap and spin. Now all of this is happening at full throttle and at 120 mph
Now you ask, if speed does not matter, then why are we taught to keep speed up to keep from stalling.
As I mentioned, speed is only one factor in a stall. AOA is the other. and now to really confuse you G load will create an aggravated stall that can be extremely violent.
So now take the same plane, flying straight and level, it's moving at 120mph but it's normal stall speed is 55mph. At 120mph you roll into a 45 degree bank and yank back on the stick to keep it level, you just added 2 g's or more depending on how hard you yanked on the stick to the plane and now your stall speed increased to roughly 70mph and as long as those "g's" are still there and you are slowing guess what will happen at 70mph per hour. Point is stall speed increases with G load. Yank too hard and the G loads can overcome the design of the plane itself and pull the wings right off. A good visual example would be to take the Stik you are going to buy and dive it from really high up at idle. At the last minute pull out hard and watch what effect G load has on the wings. I do not recommend this as I am trying to make a point.
In the past I have mentioned that the only thing that really transfers from full scale to R/C is aerodynamics and the stall is an aerodynamic property.
The above example is not that accurate when it comes to the speed examples so please be nice if I got something else wrong.
I do sincerely apologize to the original poster of this thread...
I know you are taking Full Scale lessons so we will use that and assume you are in a Cessna 150 or bigger which will help explain what Bruce is talking about
Very early in your training you should have gone through stall training. You should know that a plane can be stalled at any airspeed. So knowing that, what actually is bringing on the stall? I will give you his much. yes speed has something to do with it but not in the example I am going to explain.
Angle of Attack (AOA) has everything to do with stall speed. Exceed that angle and the wing stalls. Exceed that angle in a turn and now you have one stalled wing and not the other. Guess what happens now, snap and spin. Now all of this is happening at full throttle and at 120 mph
Now you ask, if speed does not matter, then why are we taught to keep speed up to keep from stalling.
As I mentioned, speed is only one factor in a stall. AOA is the other. and now to really confuse you G load will create an aggravated stall that can be extremely violent.
So now take the same plane, flying straight and level, it's moving at 120mph but it's normal stall speed is 55mph. At 120mph you roll into a 45 degree bank and yank back on the stick to keep it level, you just added 2 g's or more depending on how hard you yanked on the stick to the plane and now your stall speed increased to roughly 70mph and as long as those "g's" are still there and you are slowing guess what will happen at 70mph per hour. Point is stall speed increases with G load. Yank too hard and the G loads can overcome the design of the plane itself and pull the wings right off. A good visual example would be to take the Stik you are going to buy and dive it from really high up at idle. At the last minute pull out hard and watch what effect G load has on the wings. I do not recommend this as I am trying to make a point.
In the past I have mentioned that the only thing that really transfers from full scale to R/C is aerodynamics and the stall is an aerodynamic property.
The above example is not that accurate when it comes to the speed examples so please be nice if I got something else wrong.
I do sincerely apologize to the original poster of this thread...
06-09-2005 | 02:43 PM
#29
Senior Member
My Feedback: (4)
Joined: Jan 2005
Posts: 2,141
Likes: 0
Received 0 Likes
on
0 Posts
From: Madison, AL
RE: please... need help with take off
Bubba,
You misunderstand alot of what i said. I siad i was going to the fun fly to watch. Matter of fact i said " Going to the funfly" Which i assume you interpreted as Going and flying at the fun fly. I took your advice. Also, even if i did want to fly at the fun fly i couldn't because i haven't soloed with my club. I do fully understand what you said about stalling and that helped alot. I change my mind alot, but is there something bad about that. It's hard to either take the advice on what plane to get from people on here who haven't seen you fly or change your mind to do what people who have seen you fly think...
Again, that is just me.. and yes being 15 is an excuse..
-chad
You misunderstand alot of what i said. I siad i was going to the fun fly to watch. Matter of fact i said " Going to the funfly" Which i assume you interpreted as Going and flying at the fun fly. I took your advice. Also, even if i did want to fly at the fun fly i couldn't because i haven't soloed with my club. I do fully understand what you said about stalling and that helped alot. I change my mind alot, but is there something bad about that. It's hard to either take the advice on what plane to get from people on here who haven't seen you fly or change your mind to do what people who have seen you fly think...
Again, that is just me.. and yes being 15 is an excuse..
-chad
06-09-2005 | 03:00 PM
#30
RCU Forum Manager/Admin
My Feedback: (9)
RE: please... need help with take off
Ok, I've been watching this going on this afternoon and it's time that I step in. I'm not going to close down this thread because I feel that it still hasn't resolved the original issue that was presented. But there are a few here that seem to getting upset at what is going on. This needs to stop here and now. If members here can't discuss the issue at hand without getting personal then those people will be dealt with by the moderators here at RCU. I'm going to be sending out a few PM's to several posters in this thread so that hopefully we can defuse this situation and everybody can be friends. But the personal emotions needs to stay home and not out here in the open thread.
Hopefully there won't have to be anymore action taken here
Fishdeep, I do apologize that this thread has gotten a bit off of topic. Hopefully everything will get back on topic and we can get your problem fixed.
Ken
Hopefully there won't have to be anymore action taken here
Fishdeep, I do apologize that this thread has gotten a bit off of topic. Hopefully everything will get back on topic and we can get your problem fixed.
Ken
