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Old Nov 16, 2012, 10:44 AM
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DerekB's Avatar
Cape Coral, FL
Joined Nov 2001
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Originally Posted by FlyHighSelllow View Post
Interesting launch approach. Any reason this method wouldn't work for non control line EDF plane ? I supposed it would need quite a bit of thrust to get off the ramp, stay in the air before if got up on step.
I think the ramp would work for RC. With RC you have positive and subtle control over the elevator and ailerons, which is all you really need to keep it stable for those for maybe 10 feet beyond the ramp til it gets more speed. With control line, you rely on line tension which is quite minimal at take-off, but it still works. This Hawk weighs 2.0 lbs (probably gained a little after our repairs ) and 2.2 lbs thrust. It is easy to get more thrust with a more expensive motor. I was trying to use the cheapest motor possible which is $13. Not for "budget" reasons, but just to see if it works.

Derek
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Old Nov 16, 2012, 12:14 PM
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Canada
Joined Nov 2000
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Interesting Video.. Thanks.
Model did seem rather s l o w though.
However for initial flights, certainly good enuff.
AND it survived intact, nor everyone can manage that :-)
Note that CL planes typically have Far higher power needs than RC models.
Going in circles and dragging lines really sucks up the power... then throw in a few acrobatics for some serious power absorptions.
As a guess one would need 'at least' double the power of an RC setup, possibly 3 to 4X for Combat model equivalency performance.. should you want that :-).

Ohh as aside; dropping a rag at the centre of your intended flying circle helps keep one centered
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Old Nov 16, 2012, 12:56 PM
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Cape Coral, FL
Joined Nov 2001
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Quote:
Originally Posted by Bare View Post
Interesting Video.. Thanks.
Model did seem rather s l o w though.
However for initial flights, certainly good enuff.
AND it survived intact, not everyone can manage that :-)
Note that CL planes typically have Far higher power needs than RC models.
Going in circles and dragging lines really sucks up the power... then throw in a few acrobatics for some serious power absorptions.
As a guess one would need 'at least' double the power of an RC setup, possibly 3 to 4X for Combat model equivalency performance.. should you want that :-).

Ohh as aside; dropping a rag at the centre of your intended flying circle helps keep one centered
Yes, it was slow on purpose because I'm not that good at flying C/L. I was only at 1/3 to 1/2 throttle for all of the flights except for takeoff and one portion during 3rd Flight when the message "4.2 Second Laps" appears, that's when I went to full throttle for 2 laps. It was not comfortable for me, so I backed off and just stayed at 1/2 throttle or so. That gave 5 to 6 second laps, which I liked. Then for the last 2 to 3 laps before landing, I was just goosing the throttle to get a feel for "how slow can it go" for landing. I learned that if I just chop throttle, it did not glide very well (typical of EDF's - and the cause of my crash in 1st Flight) so it needs to have some power on for landing. All of which works great with the throttle control, once I got a feel for it.

I'm pretty sure at full throttle it would have looped, but I did not want to risk it since my experience is limited. I would want to hook up the flaps first before trying it. The flaps are just fixed in place for now.

The fan blade/shroud and motor ($28 combo) I am using is on the low end of thrust for a 70mm ducted fan. I'm getting 2.2 lbs static thrust for 2.0 lbs All Up Weight. With a different motor and aluminum shroud ($170 combo), this same fan blade will give 3.2 lbs static thrust with no weight gain. I'm thinking that should be enough .

Unfortunately, this Hawk will probably not get modified or upgraded any - it's at Dad's house now. He just wants to fly it as-is.

I may need to do another one for stunt .

I'm hoping somebody else will try one and chime in here!!

My Dad uses a pie plate with a nail in it to mark the center. We got the plate out after seeing how badly I was wandering .

Derek
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Old Nov 16, 2012, 12:56 PM
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FlyHighSelllow's Avatar
United States, FL, Orlando
Joined Jul 2010
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Quote:
Originally Posted by DerekB View Post
I think the ramp would work for RC. With RC you have positive and subtle control over the elevator and ailerons, which is all you really need to keep it stable for those for maybe 10 feet beyond the ramp til it gets more speed. With control line, you rely on line tension which is quite minimal at take-off, but it still works. This Hawk weighs 2.0 lbs (probably gained a little after our repairs ) and 2.2 lbs thrust. It is easy to get more thrust with a more expensive motor. I was trying to use the cheapest motor possible which is $13. Not for "budget" reasons, but just to see if it works.

Derek
Actually I have the same motor beig delivered today going in a CS 10 blade EDF going in a HK Vampire
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Old Nov 16, 2012, 04:40 PM
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Joined Jul 2012
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Quote:
Originally Posted by Bare View Post
Interesting Video.. Thanks.
Model did seem rather s l o w though.
However for initial flights, certainly good enuff.
AND it survived intact, nor everyone can manage that :-)
Note that CL planes typically have Far higher power needs than RC models.
Going in circles and dragging lines really sucks up the power... then throw in a few acrobatics for some serious power absorptions.
As a guess one would need 'at least' double the power of an RC setup, possibly 3 to 4X for Combat model equivalency performance.. should you want that :-).

Ohh as aside; dropping a rag at the centre of your intended flying circle helps keep one centered
It's something like 80% of the power output of the motor is just in overcoming the drag of the lines.
Nothing wrong with going slow. If you can slow fly and still maintain adequate line tension (i.e. safe control feel), then you are doing real well.
Combat jobs are a special case: VERY high power to wing loading ratio.
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Old Nov 16, 2012, 04:48 PM
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"My Dad uses a pie plate with a nail in it to mark the center. We got the plate out after seeing how badly I was wandering" .

Used to toss a "hula hoop" on the ground. Wandering isn't bad as long as you maintain control and don't impact any trees/people/phone poles/ tool box/ other stationary objects/etc...
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Old Jan 15, 2013, 10:02 PM
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Traian's Avatar
United States, GA, Roswell
Joined Mar 2008
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Well done
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