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Old Jul 24, 2011, 01:22 PM
Another one on the way...
ysolomon's Avatar
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Quote:
Originally Posted by heychas View Post
Yoram - I noticed from your pictures that you are using the furthest hole on your control horns on the ailerons and flaps. If you use lower holes, you will get longer throws. It works opposite of the servo arm. FYI - I believe Tam recommends to his customers to always use the lowest horn on control surfaces due to planes he has lost caused by high speed flutter using the outer control horn holes... of course w/ jets that will go much faster than this one
I'm embarrassed... I didn't think about that... I will move to lower holes on the surfaces...
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Old Jul 24, 2011, 07:31 PM
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Hi Herb,
My first flight (video) the plane rotated fine, however the second flight even with cog back a bit the plane refused to pick up enough speed for me to even feel comfortable pulling any up in, I think also a factor was the nose leg (tams) the spring has softened a bit and with slightly longer grass and bumps meant the leg was slightly folded giving a negative AOA. However I do take your comments about weight on board (I presume you mean the plane) I'm just not comfortable pulling 80A out of much less than 4000mah's so the batts will have to stay for now, the wheels are a reasonable size but could be increased. Next week is flying from an old spitfire base with a very very long mown grass strip so I can experiment a lot more.
regards
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Old Jul 25, 2011, 12:01 PM
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Yes that negative AoA could definitely be the problem! Either a stronger spring, or pull the strut out a bit so the whole leg is longer. Or use smaller wheels on the mains ?

Spitfire base, that sound nice

.
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Old Jul 25, 2011, 12:06 PM
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Very nice flying site not during the football season, a massive area that is mown like a putting green, however as soon as the footbal season starts the local council put up goal posts everywhere and limit just how much can be used. This weekend is a fly-in hosted by a local designer/manufacturer where I will be picking up my 50cc spit I think they are manketed in the US as ESM. I wont be going electric on this one but have a four stroke 50cc gas engine lined up just for the sound.
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Old Jul 25, 2011, 07:50 PM
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Eddy, well that (EMS) looks like a very nice Spit !! ... and nothing flies like a Spit but of course, you already knew that
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Old Jul 25, 2011, 08:00 PM
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I installed the strobe light on the dorsal behind the cockpit,

.
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Old Jul 25, 2011, 08:04 PM
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... for now the strobe is just secured with some tape. I want to see how visible this thing is in the bright CA sun .

It's a fairly tall unit (high voltage lamp) and there's nothing I can do about it. It is VERY bright, brighter than what it looks like in the video.

.

CMP T-45 Goshawk (BAe Hawk) strobe light (0 min 8 sec)


.
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Old Jul 25, 2011, 08:47 PM
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canopy mod

has anyone else cut there canopy in half to mod it. i would like to know how it was done
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Old Jul 27, 2011, 12:56 PM
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ESC cooling

Hi all, my build has finally been kickstarted again. I'm looking at the ducting and trying to decide how best to cool the ESC.
I am using a 120 Amp Platinum Pro and my 'cunning Plan' is to make a shroud that will feed into the left and right ducting, basically the main fan will provide forced cooling for the heatsink.

Has anyone tried this before or can anyone see a problem with this.

I have seen that some chaps have installed the heatsink into one of the ducts however I felt this might generate uneven airflow between the intakes and cause disturbed flow to the main fan.

Herb, posting your control throws came at a perfect time as I have just started setting up the control surfaces. Many thanks.

I am hoping to have my T-45 test flown here in the UK, unfortuantly due to my flying location I can't provide a video, but I will certianly give a full feedback.
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Old Jul 27, 2011, 01:04 PM
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I found this Youtube clip from a German CMP T-45 build thread, I think Herb might have post the link to their thread before but here it is:
Thread:

http://www.rc-network.de/forum/showt...ara-CMP/page22

Video:
CMP T45 Rolf (1 min 32 sec)


My German is non existant but as they say a picture paint a 1000 words. They have really gone to town on theirs.

Enjoy

Marvin
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Old Jul 27, 2011, 01:05 PM
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Hey Marvin,

Whereabouts are you in the UK, Mine will hopefully be flown this weekend from the Greenacres/ YT funfly event in Aldridge.
Regards
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Old Jul 27, 2011, 01:42 PM
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Quote:
Originally Posted by Marvinrobot1510 View Post
[...] I'm looking at the ducting and trying to decide how best to cool the ESC. I am using a 120 Amp Platinum Pro and my 'cunning Plan' is to make a shroud that will feed into the left and right ducting, basically the main fan will provide forced cooling for the heatsink. Has anyone tried this before or can anyone see a problem with this. I have seen that some chaps have installed the heatsink into one of the ducts however I felt this might generate uneven airflow between the intakes and cause disturbed flow to the main fan. [...]
Hi Marvin, I think you are using exactly the same ESC as I am (see pics), mine's called K-Force...

I don't have a whole lot of cooling besides the air that comes in through the nosegear opening (good to have that one ) and from the two little blisters.

Any minimal amount of airflow is much better than none ... If it makes you feel better you can just make a nice round hole or two, 1cm or less diam, close to where the esc cooling fins are located ?

That will suck a ton of air right over the esc, where it matters.

Cutting a huge chunk of ducting out (and weakening the duct in the process) to put that monster esc in the airflow is silly overkill imo.

Run it up and see how warm it gets ... then go from there.
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Old Jul 27, 2011, 06:14 PM
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Originally Posted by Eddie-extra View Post
Hey Marvin,

Whereabouts are you in the UK, Mine will hopefully be flown this weekend from the Greenacres/ YT funfly event in Aldridge.
Regards
Hi Eddie, I fly near Amesbury...read between the lines for why I can't video.
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Old Jul 27, 2011, 06:26 PM
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[QUOTE=Herb;18878857]Hi Marvin, I think you are using exactly the same ESC as I am (see pics), mine's called K-Force...

Any minimal amount of airflow is much better than none ... If it makes you feel better you can just make a nice round hole or two, 1cm or less diam, close to where the esc cooling fins are located ?

Cutting a huge chunk of ducting out (and weakening the duct in the process) to put that monster esc in the airflow is silly overkill imo.

H i Herb, I was looking to place the ESC flat (in relation to the wing) and cut 2 5mm slots about 25 mm long in each duct, reinforcing the duct with thin ply around the slot. I would then put a shroud over the ESC cooling fins to direct the air. I was not intending on putting the ESC into the ducting as you quite rightly pointed out the ducted is not strong enough.

I have left the nose area open so air can still get in I just want a bit of forced cooling for peace of mind, it beats wasting energy by sticking a fan ontop of the ESC when you have a really big one at the back.
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Old Jul 29, 2011, 12:10 PM
DELTAS RULE
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tehachapi, CA
Joined Jan 2006
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you refering to the new jetfan 90?



Quote:
Originally Posted by Herb View Post
Yes JePe nailed it with that scale sound nonsense

Most of the time scale (ie turbine) sound means : bad inlets, bad ducting and poor fan efficiency, or all of the above

Case in point, the new 90mm high blade count fan is perhaps a glaring example, a whopping 9% fan efficiency lost to rather useless sound effects .

Some don't seem to realize that turbine-like noise is just due to very bad turbulence. The sign of good fan efficiency is in fact no sound !!

I had an F-86 with bad ducting that made a fantastic turbine-like noise . Until I fixed the shape of the intake, then it went quiet.
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