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Old Dec 04, 2011, 07:19 PM
Registered User
Australia, NSW, Plumpton
Joined Jan 2008
406 Posts
my question is still same, forget about flying the plan and adjust elevator, i m concern about CG

. 1 : in video when i fly yes its go up (elevator was in normal setting )
. 2 : i did it trim up ( so from tail side it should up " force plan to move down ")

question is that if i go to actual CG which is as per plan 2.9 (cuz my length is small)
plan already heavry from nose as you can see in video so why when i fly it its going up ? showing its tail heavy,

i can not move batter more forward cuz 2.9 cg showing alrady heavy from nose

if i pull battery back , then that mean when i will fly plan it will more heavy from tail

ahh lot of confusion.


its flying good with CG 2.1 and elevator trim up (arround 10degree or 15degree up)
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Old Dec 04, 2011, 09:15 PM
Fidler & twidler
empeabee's Avatar
Cranfield U.K.
Joined Mar 2004
4,087 Posts
Quote:
Originally Posted by aqkhana2002 View Post
my question is still same, forget about flying the plan and adjust elevator, i m concern about CG

. 1 : in video when i fly yes its go up (elevator was in normal setting )
. 2 : i did it trim up ( so from tail side it should up " force plan to move down ")
Up elevator forces the tail Down, to lift the heavy nose up. You can get the same effect by moving the battery back towards the tail and reducing the Up elevator trim.
Quote:

question is that if i go to actual CG which is as per plan 2.9 (cuz my length is small)
plan already heavry from nose as you can see in video so why when i fly it its going up ? showing its tail heavy,

i can not move batter more forward cuz 2.9 cg showing alrady heavy from nose

if i pull battery back , then that mean when i will fly plan it will more heavy from tail

ahh lot of confusion.


its flying good with CG 2.1 and elevator trim up (arround 10degree or 15degree up)
A little bit of aerodynamics.
The faster you go, the elevator becomes more powerful and with the large elevator trim you have, if you dive and go faster, so the nose will come up automatically, and you have to push the nose down to stop this zooming up. If you move the batter back (a small bit at a time) you will be able to reduce the Up trim, so reducing the effect of speed variation.
There will come a point where you get the balance point too far back, and the aircraft will become very sensitive to elevator control, and become difficult to fly - your balance point is now too far back.
Many trainer aircraft are setup nose heavy because it is self stable, as the speed goes down, so the nose drops the increase the speed, and as the speed increases the nose rises to reduce the speed, which is good while you are learning to fly, but this make aerobatics difficult, and people then move the balance point backwards (a little at a time) as their skill increases. But even the best pilot in the world will fail to fly an aircraft with its balance point too far back, which is why I said move the balance point back s l o w l y.
Hope this helps
Mike
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Old Dec 05, 2011, 05:31 PM
Registered User
Australia, NSW, Plumpton
Joined Jan 2008
406 Posts
is there any one who is using 2200MAH Battery for this plan and have pic to show where is his batter location?
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Old Dec 05, 2011, 05:40 PM
Pusher jets rule!
crxmanpat's Avatar
Mesa, AZ
Joined Jan 2006
17,679 Posts
Aqeel,

A lipo that big can be used, but you have to shove it way far back to make the CG. A different size of battery won't change where the CG needs to be located. You just need to find the proper CG first, then place the lipo in a position that makes the plane balance on the proper CG point.

Pat
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Old Dec 10, 2011, 03:04 PM
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umdpru's Avatar
United States, MA, Boston
Joined Jun 2006
1,086 Posts
Im using one that big. The battery needs to be at the very back of the cockpit area for balance. I like the longer flight times but I do notice the extra weight, though.
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Old Dec 21, 2011, 01:50 PM
jhi
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Norway
Joined Jun 2009
175 Posts
Steve Shumate's "F-15 Eagle" - maiden

Hi all!

Motor: RCTimer 2212-6 http://www.rctimer.com/index.php?gOo...6&productname=
Servos: RCTimer MG9025 http://www.rctimer.com/index.php?gOo...8&productname=
Battery: Turnigy 1.6Ah nano
ESC: HobbyKing HW30A (25A - max.30A)
Propeller: APC style 6x4 (pusher)
Radio: Futaba T7C (programmed with "Flaperon mix" and "Air brake")
AUW: 22.3oz (632g)

Again, thank you Steve Shumate for your plans, excellent drawings and instructions! Easy to follow and makes the building process a joy. This is my third depron model, previously I have built the Polaris and the Sukhoi SU-37.

Maiden yesterday, and I have mixed feelings. Not because of the plane, but because of my flying! I have decided to include the entire maiden flight, hoping to receive some good advice from the experts. I was tempted to take the plane up again at once, but resisted, I felt that I had had spent all my luck for one day.

You can see I had no control at around 60s on the video. After two right turns it started to become boring and I wanted to make a left turn . Maybe because of too much throw combined with a lot of expo (40%) things got out of hand, and I nearly crashed. For a second or two I could not see the plane but kept flying - throttled up, a little up elevator and to my surprise I could see the plane again! The aileron throw is about ±38mm, and elevator is ±35 - Steve's recommodation is ±1 1/2" (38mm) and ±2" (51mm). How much throw do you have guys?

Takeoff. The propeller is a APC 6"x4" pusher (turning left), so I got an expected right roll right after launch. I guess it is normal since I probably used too much throttle (got too excited!), but could easily correct in time. Next time I shall try with less throttle..

/Jan

F-15 Eagle maiden.mp4 (3 min 25 sec)



Here are some photos of my F-15 Eagle as "required" by Steve
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Last edited by jhi; Feb 03, 2012 at 05:57 PM. Reason: Added specs
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Old Dec 21, 2011, 03:15 PM
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Germany
Joined May 2009
51 Posts
well done, great plane :-)
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Old Dec 21, 2011, 03:47 PM
Falcon's rc
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USA, GA, Byron
Joined Apr 2009
241 Posts
nice looking plane jhi
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Old Dec 21, 2011, 03:56 PM
Kiss the Sky
electriceye's Avatar
Dorking, Surrey, UK
Joined Jul 2006
2,862 Posts
Yes, both look cool to me? A bit of torque roll perhaps on take off? Also, maybe reduce your elevator throw or use some expo? Other than that it looked cool? But I am a long, long way from being any kind of expert pilot!!! Good lookung models/lovely flying site!
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Old Dec 21, 2011, 06:34 PM
Have Fun! Land, Sea or Air
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United States, TX, Austin
Joined Jul 2006
1,358 Posts
Really nice F-15. Great job shaping the nose cone.
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Old Dec 21, 2011, 08:42 PM
Registered User
Australia, NSW, Plumpton
Joined Jan 2008
406 Posts
awesome..

Quote:
Originally Posted by jhi View Post
Hi all!

Motor: RCTimer 2212-6 http://www.rctimer.com/index.php?gOo...6&productname=
Servos: RCTimer MG9025 http://www.rctimer.com/index.php?gOo...8&productname=
Battery: Turnigy 1.6Ah nano
ESC: HobbyKing HW30A (25A - max.30A)
Propeller: APC style 6x4 (pusher)
Radio: Futaba T7C (programmed with "Flaperon mix" and "Air brake")
AUW: 22.3oz (632g)

Again, thank you Steve Shumate for your plans, excellent drawings and instructions! Easy to follow and makes the building process a joy. This is my third depron model, I have previous built the Polaris and the Sukhoi SU-37.

Maiden yesterday, and I have mixed feelings. Not because of the plane, but because of my flying! I have decided to include the entire maiden flight, hoping to receive some good advice from the experts. I was tempted to take the plane up again at once, but resisted, I felt that I had had spent all my luck for one day.

You can see I had no control at around 60s on the video. After two right turns it started to become boring and I wanted to make a left turn . Maybe because of too much throw combined with a lot of expo (40%) things got out of hand, and I nearly crashed. For a second or two I could not see the plane but kept flying - throttled up, a little up elevator and to my surprise I could see the plane again! The aileron throw is about ±38mm, and elevator is ±35 - Steve's recommodation is ±1 1/2" (38mm) and ±2" (51mm). How much throw do you have guys?

Takeoff. The propeller is a APC 6"x4" pusher (turning left), so I got an expected right roll right after launch. I guess it is normal since I probably used too much throttle (got too excited!), but could easily correct in time. Next time I shall try with less throttle..

/Jan

https://www.youtube.com/watch?v=kzM9R6xrGYo


Here are some photos of my F-15 Eagle as "required" by Steve
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Old Dec 21, 2011, 11:30 PM
Park Jet Guru
jetset44's Avatar
Seattle, WA
Joined Jun 2002
5,616 Posts
Great looking model, jhi, and you're welcome for the plans! In the video, it looks like it fly fine before and after the incident at the 60 sec mark, so my hunch this was just pilot disorientation, possibly combined with excessive stick inputs. That's easy to do with a white model against a snowy white background! And yes, roughly 60% throttle is all you need to get in the air smoothly and without torque roll.

Thanks for the pics and video! And good luck on the second flight.

Steve
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Old Dec 23, 2011, 06:53 AM
jhi
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Norway
Joined Jun 2009
175 Posts
My F-16 Eagle maiden.

Thank you all for nice comments and good advice!

I have lowered the R/C rate a little and also reduced previous -40% expo (Futaba) to -35% expo. To help with orientation I also painted some more under the wings - similar scheme to the one above the wing. Waiting for weather to improve, too windy and rainy at the moment - fingers crossed.

Merry Christmas and fly safe!

/Jan
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Old Dec 27, 2011, 11:16 AM
Registered User
al_cappuchino's Avatar
Germany
Joined May 2009
51 Posts
F-15 Crash

Hello Friends,

my 100% F-15 crashed today.
I have to bulild a complete new forward fuselage:
Nosecone
Forward Fuselage Side
Bulkheads...
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Old Dec 27, 2011, 06:24 PM
USA, Massachusetts
rcflyer50's Avatar
Joined Dec 2005
359 Posts
Beautiful plane and beautiful country!
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