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G&L 1/5 DHC chipmunk - diary of a build.

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G&L 1/5 DHC chipmunk - diary of a build.

Old 10-07-2014, 12:02 PM
  #876  
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That suck's beyond comprehension.
Old 10-07-2014, 12:12 PM
  #877  
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So sorry.
Old 10-07-2014, 12:26 PM
  #878  
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Originally Posted by RCKen View Post
Please tell me that you are kidding Tony. After all the work you put into this plane I would hate to see that it's gone to a stall. Please say it ain't so!!

Ken
unfortunately yes she is gone to a stall. That is the result of a to heavy plane. All previous landings were ok but not perfect. But this time I think I was over heating and lost power (not a dead stick) and she stalled about 50 feet short of the runway on a routine approach. The plane just dropped and bounced up then hitting the left wing on the ground shearing it off at the end of the spar. Then a cartwheel separating the stab from the fuselage.

I was concerned about the high wing load and the overheating possibilities of the scale cowl.

Repairs are not in the plan as of now, to much damage and the fact that she was so heavy and the cowl issues does not make sense to repair.

This is always a possibility with highly modified and detailed kits, I know this but it does not deter me. I will say Johnny 5 served a great service in showing me that most of my ideas worked and are good for Angie. I have learned I just can't build without regard to weight or things like engine cooling.

15 good flights was worth the time spent building, I do wish that things turned out better but it was only a mater of time at that weight.
I will build one more in time as a super chipmunk but that will be after Angie.


TB
Old 10-07-2014, 12:29 PM
  #879  
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Great attitude tony.
Old 10-07-2014, 12:50 PM
  #880  
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T/B sorry to hear about your chippy

cheers Bob T
Old 10-07-2014, 03:16 PM
  #881  
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Default Some comments _ _ _

Addressed to the general reader ( viewer ) which includes participants.

Do not be surprised to read objections to my following comments.
If objections are posted I hope they will point to specifics and offer a correction with explanations.

Comments

Stalling is not the results of heavy weight ( high wing loading ). It is the result of exceeding the stalling angle of attack of the wings. That can happen at any wing loading. The wing angle of attack is self adjusting in any specific flying condition.

Airliners with high wing loading can glide at about the same angle of descent as light airplanes do. The difference is in the speed of travel.

A relationship, as one example, is that at twice the weight the speed has to be 1.41 times faster.

There is a method of judging the final approach angle of attack by looking at the horizontal tail surface versus the main wings. That is determined by observations while practicing stalls at sufficient altitude in level flight. Rarely is the angle of attack of the main wings more than 6 to 8 degrees on a stable approach rate of descent. This is where the setting of the decalage and the CG location is important.

At cruising speed the elevators should be neutral in line with the stabilizer while the airplane is not climbing and not descending ( level straight flight ). We should choose an engine to establish cruise speed at about half throttle opening of the carburetor ( not the transmmitter stick position ).

Note that I am not talking about airplane shaped helicopters _ _ _ aka _ _ _ 3D flying.
I am talking about normal realistic model airplane flying including patterns and aerobatics.

Some crash damage reduction methods.

A compression strong component from the firewall to behind the wings trailing edges.
This or these components can often be used as the engine mount.

A high compression resistant component between the wings leading edge and trailing edges to reduce or prevent the fuselage from breaking inward.

A high tension resisting component at both the wing leading edges and trailing edges to reduce or prevent the fuselage from breaking outward.

Some hard wood component in the fuselage structure to the tail assembly with diagonal crossings to reduce break away of the fuselage behind the wings.

A covering material resistant to tearing with a surface finish that does not affect the strength of the covering material.

I invite anyone to add to these basic principles.

Zor

Old 10-07-2014, 03:30 PM
  #882  
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Originally Posted by TonyBuilder View Post

unfortunately yes she is gone to a stall. That is the result of a to heavy plane. All previous landings were ok but not perfect. But this time I think I was over heating and lost power (not a dead stick) and she stalled about 50 feet short of the runway on a routine approach. The plane just dropped and bounced up then hitting the left wing on the ground shearing it off at the end of the spar. Then a cartwheel separating the stab from the fuselage.

I was concerned about the high wing load and the overheating possibilities of the scale cowl.

Repairs are not in the plan as of now, to much damage and the fact that she was so heavy and the cowl issues does not make sense to repair.

This is always a possibility with highly modified and detailed kits, I know this but it does not deter me. I will say Johnny 5 served a great service in showing me that most of my ideas worked and are good for Angie. I have learned I just can't build without regard to weight or things like engine cooling.

15 good flights was worth the time spent building, I do wish that things turned out better but it was only a mater of time at that weight.
I will build one more in time as a super chipmunk but that will be after Angie.


TB
Tony,

It is up to you but I think many of us who have faithfully followed your build would like to see pictures of the failing locations. Pictures covering a wide enough area to know where the failures were and see which component separated.

Thanks,

Zor

Last edited by Zor; 10-07-2014 at 03:32 PM.
Old 10-07-2014, 04:29 PM
  #883  
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Tony,

I have followed your build from the beginning.
First I want to thank you for sharing your build with us. Faithfully, daily updates. In-depth descriptions of what you were doing what you used and how you used it. Just a great build diary full of educational stuff.
Thank You !!!!!!

My heart felt condolences for the early retirement of Johnny 5. Said day to say the least.

Kevin
Old 10-07-2014, 04:34 PM
  #884  
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Tony,I can't believe Johnny 5 is gone.This thread was one that I really enjoyed. I look forward to your build of Angie.
Sorry for your loss,Bill
Old 10-07-2014, 04:39 PM
  #885  
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Originally Posted by Zor View Post
Tony,

It is up to you but I think many of us who have faithfully followed your build would like to see pictures of the failing locations. Pictures covering a wide enough area to know where the failures were and see which component separated.

Thanks,

Zor
I prefer to to remember her the way she was in all her glory, no pics please.....
Old 10-07-2014, 05:06 PM
  #886  
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I'm with you Gary. I've seen my fair share of beautiful scale planes go in. Never pretty. Well just remember ol chippy as she was. Beautiful.
Old 10-07-2014, 05:33 PM
  #887  
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Originally Posted by Zor;11895419[COLOR=#000000

[/COLOR]Some crash damage reduction methods.

A compression strong component from the firewall to behind the wings trailing edges.
This or these components can often be used as the engine mount.

A high compression resistant component between the wings leading edge and trailing edges to reduce or prevent the fuselage from breaking inward.

A high tension resisting component at both the wing leading edges and trailing edges to reduce or prevent the fuselage from breaking outward.

Some hard wood component in the fuselage structure to the tail assembly with diagonal crossings to reduce break away of the fuselage behind the wings.

A covering material resistant to tearing with a surface finish that does not affect the strength of the covering material.

I invite anyone to add to these basic principles.

Zor

Once you start building to avoid crash damage, you might as well go down to the home improvement center and buy a cinder block. That is what you will end up with in the end. Build a plane to fly, not to survive a crash, that is my motto.
Old 10-07-2014, 05:42 PM
  #888  
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Originally Posted by redbiscuits View Post
I prefer to to remember her the way she was in all her glory, no pics please.....
No wreckage pics will be posted.

TB
Old 10-07-2014, 05:43 PM
  #889  
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Originally Posted by Melchizedek View Post
Tony,

I have followed your build from the beginning.
First I want to thank you for sharing your build with us. Faithfully, daily updates. In-depth descriptions of what you were doing what you used and how you used it. Just a great build diary full of educational stuff.
Thank You !!!!!!

My heart felt condolences for the early retirement of Johnny 5. Said day to say the least.

Kevin
thank you Kevin


TB
Old 10-07-2014, 05:51 PM
  #890  
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Tomorrow I will disassemble Johnny 5. There is some talk of gluing her back together and mounting the frame out at the field above the field sign as a display.

So Johnny 5 may live on as a tribute to what we pilots and builders do.

TB
Old 10-07-2014, 05:59 PM
  #891  
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Default How much damage ?

It is hard to believe in much damage to the structure.

Being 50 feet from the runway as read in post # 878 she would not be more than 10 feet or so above the ground and likely in the flare out.

When a model stalls it does not fall like a brick nearly vertically.

Part of this post has been edited to comply with TonyBuilder's wishes not to repair his Chipmunk.

Zor

Last edited by Zor; 10-08-2014 at 04:44 AM. Reason: See blue text above
Old 10-07-2014, 06:01 PM
  #892  
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who is or what is Angie
Old 10-07-2014, 06:28 PM
  #893  
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T/B I have to ask a question IF you would have had your telemetry air speed set up for stall warning, do you think it would have made a difference ? I have been to several flyins this season and have seen they same thing happen then t/t the pilots and every one said they wish they had a stall warning, but most do not want to spend the $$$ to go to the new gear


Cheers Bob T
Old 10-07-2014, 06:28 PM
  #894  
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Originally Posted by redbiscuits View Post

Once you start building to avoid crash damage, you might as well go down to the home improvement center and buy a cinder block. That is what you will end up with in the end. Build a plane to fly, not to survive a crash, that is my motto.
redbiscuits,

You have your experience and I have mine.

There is no need to have much extra weight following the basic principles I talked about.

Any modifications made to achieve the reduced damage risks simply take into consideration the material used and the structure modifications. Some modifications can be very strong and weight next to nothing.

Example _ _ _ a piece of steel wire 4 inches long that will never break in tension.
An engine bearer of 3/8" x 3/8" x 18" that weigh 38 grams instead of a commercial mount can prevent a break away of a complete engine installation.

We all have our own way of making modifications depending on our experience and material knowledge.

Zor
Old 10-08-2014, 02:39 AM
  #895  
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Originally Posted by rye View Post
who is or what is Angie


http://www.rcuniverse.com/forum/kit-...-build-61.html






TB
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Old 10-08-2014, 02:56 AM
  #896  
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Originally Posted by rt3232 View Post
T/B I have to ask a question IF you would have had your telemetry air speed set up for stall warning, do you think it would have made a difference ? I have been to several flyins this season and have seen they same thing happen then t/t the pilots and every one said they wish they had a stall warning, but most do not want to spend the $$$ to go to the new gear


Cheers Bob T
Bob I had the telemetry and the Pitot tube installed but had issues and could not get my telemetry to work so I decided to go forward with the test flights without it. Would it have helped, I think so but again I think I was loosing power on my approach as I always fly in with a little power until I am at the landing area.

Flying off the grass was the way I was able to get around having to have air speed indication and stall warning. The stall on this plane happens fast. One second you are flying and the next it is not. The grass runway gave me 3x the landing area and I did not have to time it so I was at a specific speed at a specific point. When landing on a smaller strip of asphalt you have to be right on or you overshoot the end of the runway. Speed indication and stall warning will help you nurse the plane into that window. In my case it may have saved the plane or not. If the engine was overheating and loosing power there is nothing one can do.

Angie will have a working Pitot tube and telemetry. I am setting up an ARF with the DLE85 and all the electronics that will be going into Angie, telemetry and the Pitot tube. This will all be tested and working before I put it into Angie.

I am not making any excuses, I stalled and that was my fault. All I can do now is moving forward and learn from this and every thing I do is added experience that will make Angie that much more successful.
So to answer your question, yes the Pitot tube would have helped and I am a strong supporter of this technology and I have even convinced others at my field to put them in there high dollar planes (jets). Johnny 5 was a test bed for Angie and one of the things to be tested was the telemetry, that was unsuccessful but the other components were.



TB
Old 10-08-2014, 03:13 AM
  #897  
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Originally Posted by Zor View Post
It is hard to believe in much damage to the structure.

Being 50 feet from the runway as read in post # 878 she would not be more than 10 feet or so above the ground and likely in the flare out.

When a model stalls it does not fall like a brick nearly vertically.

Pictures of the damages does not prevent fellows from remembering its initial beauty.
I was thinking about doing the repair work for Tony if arrangments of transportation can be arranged.

Tony would pay the transportation and packaging.
My work would be at no charge to Tony
He could end up having to retouch the paint to original color in repaired areas .

Feel free to PM me Tony.

Zor
In fluid dynamics, a stall is a reduction in the lift coefficient generated by a foil as angle of attack increases. This occurs when the critical angle of attack of the foil is exceeded.

A stall is a condition in aerodynamics and aviation wherein the angle of attack increases beyond a certain point such that the lift begins to decrease. The angle at which this occurs is called the critical angle of attack. This critical angle is dependent upon the profile of the wing, its planform, its aspect ratio, and other factors, but is typically in the range of 8 to 20 degrees relative to the incoming wind for most subsonic airfoils. The critical angle of attack is the angle of attack on the lift coefficient versus angle-of-attack curve at which the maximum lift coefficient occurs.[SUP][citation needed][/SUP]
Flow separation begins to occur at small angles of attack while attached flow over the wing is still dominant. As angle of attack increases, the separated regions on the top of the wing increase in size and hinder the wing's ability to create lift. At the critical angle of attack, separated flow is so dominant that further increases in angle of attack produce less lift and vastly more drag.[SUP][citation needed][/SUP]
A fixed-wing aircraft during a stall may experience buffeting or a change in attitude. Most aircraft are designed to have a gradual stall with characteristics that will warn the pilot and give the pilot time to react. For example, an aircraft that does not buffet before the stall may have an audible alarm or a stick shaker installed to simulate the feel of a buffet by vibrating the stick fore and aft. The "buffet margin" is, for a given set of conditions, the amount of ‘g’, which can be imposed for a given level of buffet. The critical angle of attack in steady straight and level flight can be attained only at low airspeed. Attempts to increase the angle of attack at higher airspeeds can cause a high-speed stall or may merely cause the aircraft to climb.[SUP][citation needed][/SUP]
Any yaw of the aircraft as it enters the stall regime can result in autorotation, which is also sometimes referred to as a 'spin'. Because air no longer flows smoothly over the wings during a stall, aileron control of roll becomes less effective, whilst simultaneously the tendency for the ailerons to generate adverse yaw increases. This increases the lift from the advancing wing and accentuates the probability of the aircraft to enter into a spin.[SUP][citation needed][/SUP]
Depending on the aircraft's design, a stall can expose extremely adverse properties of balance and control, in particular in a prototype




Zor, if you read back I explained what happened and what the damage was, but still no pics will be posted. Yes the plane was only 5-10 feet off the ground when it staled. When I say stalled I mean stopped flying, lose of lift what ever you want to call it. I don't have a lot of experience so sometimes I may not use the right terminology that the more experienced pilots have. It is my understanding that stall is when the wing no longer has lift and stops flying....Different aircraft types have different stalling characteristics. A benign stall is one where the nose drops gently and the wings remain level throughout, that is what happened to me.

Could this plane be repaired or fixed? absolutely, will I..... no. The damage is fare to extensive for my liking.

Hope this clears it up for you.



TB
Old 10-08-2014, 03:51 AM
  #898  
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First I would like to say how sorry I am for your loss Tony, I also followed your build so I know you put heart and soul into that airplane.


Comments from Zor


Stalling is not the results of heavy weight (high wing loading). It is the result of exceeding the stalling angle of attack of the wings.

Yes, but it is much more likely to happen on a heavily loaded wing then a light loading. Heavy wing loadings are just not that forgiving, it's just that simple Zor...

Some crash damage reduction methods.

Forget that nonsense Zor, building to fly not crash is the answer. The heavier they are, the harder they hit the ground when things go wrong. Running your biplane out of fuel and softly crashing into the treetops is a much different scenario than crashing directly into the ground so you may as well build to fly and enjoy and enjoy the benefits of a lighter loaded wing...


Bob
Old 10-08-2014, 04:33 AM
  #899  
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Default It clears it up for me

Originally Posted by TonyBuilder View Post

>
>
>
This deleted text was an extract from Wikipedia on aerodynamics.
It can be read in Tony's posting.
>
>
>

Zor, if you read back I explained what happened and what the damage was, but still no pics will be posted. Yes the plane was only 5-10 feet off the ground when it staled. When I say stalled I mean stopped flying, lose of lift what ever you want to call it. I don't have a lot of experience so sometimes I may not use the right terminology that the more experienced pilots have. It is my understanding that stall is when the wing no longer has lift and stops flying....Different aircraft types have different stalling characteristics. A benign stall is one where the nose drops gently and the wings remain level throughout, that is what happened to me.

Could this plane be repaired or fixed? absolutely, will I..... no. The damage is fare to extensive for my liking.

Hope this clears it up for you.



TB
Thanks for your reply to my offer to help Tony even though you did not specifically refer to it.

You do not wish to have the Chipmunk repaired and your decision has to be respected.

When a stall occur the plane does not stop flying; it encountesr an aerodynamic wing condition in which the smooth airflow change to a turbulent fllow.above its upper surface. It can be a slow process or a very rapid one depending on the rate at which the change of the angle of attack is taking place.

You have faithfully installed strips at the wing leading edges near the fuselage like the full size has.
In the full size Chipmunk these strips create a buffeting effect noticeable to the pilot when approaching the stalling angle of attack. Of course they do not help while flying RC from the ground.

I wish to thank you for your Wikipedia insert in your post. The links do function and this information can be helpfull for many readers.

I will edit my post # 891 to get along with your desires.

Best to you with Angie ( the P47 ) now that you have posted what has been referred to as "angie".
Myself I asked at one time but it was overlooked at that time.

Best regards always . . . .

Zor

Last edited by Zor; 10-08-2014 at 04:46 AM.
Old 10-08-2014, 05:19 AM
  #900  
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T/b Thanks for the straight answer as I have done the same thing and wished I had stall warning of some kind.

Cheers Bob T,

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