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Old Oct 28, 2010, 10:07 AM
Rochester, NY
JustGoFly's Avatar
United States, NY, Monroe
Joined May 2004
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Quote:
Originally Posted by davereap View Post
Have a care,with any silica filler thats fine and floaty you need a facemask to stop it getting in your lungs... silicosis is no fun..
Thanks for the safety tip. A buddy of mine got pneumonia from sniffing CA all weekend during a build. I'd guess floaty glass particles are worse.

Looks like another week before the sun goes down earlier. Daylight savings will move flying after work possible only for night flyers. So it's weekend flying from now on - bummer. It's a long stretch until March when it opens up again. Adding the North East cold weather and it becomes build season, with frozen flying on weekends. I have alot of projects planned.

Thanks !
Vinnie
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Old Oct 31, 2010, 06:29 AM
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Ashford. Kent. England
Joined Feb 2005
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For night flying try these... but you will have to fly a bit slower
http://www.rcgroups.com/forums/showthread.php?t=987191
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Old Oct 31, 2010, 03:53 PM
The Kid
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Detroit, MI
Joined Dec 2007
2,587 Posts
Quote:
Originally Posted by JustGoFly View Post
Anyone flying a Hot Liner ? I've been looking at some and wonder what you guys recommend ? I want something I can see - not a microscopic Rifle.

Vinnie
Hey Vinnie, I quite enjoy my Siren. It is not a horrible performer. It will do loops and rolls fine, and with enough power climb like crazy. Also, it thermals decently enough. A 4 second run with my setup is enough to glide without thermalling for upwards of 5 minutes.

Great Planes Siren Hotliner 2200W (4 min 11 sec)


Its not the strongest airframe, but it goes like stink and its cheap. If you're looking for an actual "hot-liner" then the best one for bang-for-the-buck is the Enigma from SoaringUSA.

You said Rifle, which makes me think you're just looking for a very fast electric plane, aka a pylon model not a hotliner. In which case, the next size up from the Rifle would be the always popular Sunracer V2/V3. Tasajara (spelling?) also has one. They go very very fast and are not overly difficult to see. I love my Sunracer, as well as my Escape. Unfortunately the later is no longer available

Escape Pylon Compilation (4 min 10 sec)


Kid
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Old Nov 01, 2010, 05:21 PM
Rochester, NY
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United States, NY, Monroe
Joined May 2004
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- Very impressive. You are right - a pylon racer is what I'd like to get into next. I know I can handle high speed of a small plane, but would prefer as big as possible. I've been looking at http://www.icare-rc.com/pylon_racer.htm - any advice on those planes ?

I loved the vids - looks like a blast. I know Tas loves his pylon racer too.

I started the rebuild of my 30% Pitts Challenger last night. A buddy of mine is a master builder and has no hesitation in cutting a wing off and rebuilding from scratch. I felt like I was holding the flashlight for my Dad when I was a little kid. He put on some extremely cool WarBird funfly DVD's - so we had a good day, of patiently and meticulously started rebuilding the plane. I flew it TWICE without realizing it was tail heavy. It didn't FEEL tail heavy since it didn't porpoise and flew perfectly straight, but on inverted flight it would climb. I did a flat spin and couldn't get it to come out in time so did some serious damage to it - it's too painful to post the photos. It's a rare plane so I have to rebuild it. He looked over my 27% Sukhoi SU-26 and found some issues I hadn't seen. Man - what luck in having buddies who know their sheet. Makes it seem like the guys I help are ameba compared to some of these guys. Gotta think when they go to our R/C winter parties what they think when they see someone giving out build advice. I showed him the aileron connector I planned on using - basically a 2-56 rod and metal clevis. He showed me his - 4-40 rod, with aluminum tube over the rod - cut to fit exactly between two metal clevis and Hysol to fill the tube. HYSOL ? You don't know what HYSOL is - ahah - you newbie ! Hahaha. I guess we'll all newbies at something. Just too much to learn - which is why I love this hobby.

Vinnie
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Old Nov 22, 2010, 09:25 PM
SSpiff
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Long Beach, CA
Joined Mar 2009
28 Posts
MP Twin Jet

Hi All,

I just bought a MP Twin Jet, and I am trying to figure out what PS's to use.
I want to keep it light. Does anyone have any suggestions for
Light SpeeD?
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Old Nov 23, 2010, 12:52 PM
just Some Useless Geek
Chicagoland
Joined Oct 2008
2,544 Posts
Hail, Spaceman Spiff! Surely you didn't think you were the only one reading Calvin and Hobbes, eh?

Is your intent for the light weight, or the speed? Because you can have one or the other, but you gotta pick one.
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Old Nov 24, 2010, 11:26 AM
SSpiff
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Long Beach, CA
Joined Mar 2009
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Quote:
Originally Posted by A Useless Geek View Post
Hail, Spaceman Spiff! Surely you didn't think you were the only one reading Calvin and Hobbes, eh?

Is your intent for the light weight, or the speed? Because you can have one or the other, but you gotta pick one.

I think you are the first person to figure it out!

I would like to have speed at a relatively light weight. After looking at some of the earlier posts, I think I am going to use two MicroDan outrunners.
It looks like I can make some mounts for the motors and use two light-weight
4S LiPo's. That should do the trick.
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Old Jan 24, 2011, 04:46 PM
Registered User
The Netherlands, LI, Venray
Joined Dec 2008
1,405 Posts
motor angle

Someone found after 2 years a complete twinjet with 2 speed 400 brush motors on his ceiling,
i needed only to install the ESC , receiver and lipo.
COG is at spot, i flew the twinjet today , i had to downtrim (couple of clicks) the elevator to keep it straight at half throttle.

When i go to WOT it starts to climb at an angle of approx 30 degrees , i know it is related to the motor angle. I have read some posts ( from JustGoFly) and is talking about :
remounted the motors to be square to the thrust line.

I dont understand here what is the thrust line, is there a picture that makes it more clear ? Should thrustline go through the COG point?

In which direction and how much do i need to change the motor angle ? see picture of current motorangle .

Hope someone can explain this to me , thanks in advance
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Old Jan 24, 2011, 10:05 PM
Rochester, NY
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United States, NY, Monroe
Joined May 2004
1,883 Posts
Hi Jaccies,

If you point below the nose - it will fly nose up, and climb under power. Some power systems are setup that way since they fly easier and better at slow speeds. Try shimming the nose to be more level - not perfectly level. I mount mine lower than your photo and level - but I also have a lot more power so it is pushing right on the thrust line 90 degrees to the thrust line. I do this for Strykers, Projeti's and get alot more speed and rock solid control. You should be able to toss between full power and off and the nose should not dip or climb. It should remain rock steady. Do this test until you get the angle perfect.

A simple test we do is to trim the Jet to fly level at 1/2 throttle. Then fly by level and as it passes - gun the throttle and see if it climbs or dives. Climb = Shim motor back down a little, Dive=shim the motor back up a little.

Note - the opposite happens when you land. If it climbs under power - you are holding the nose down with elevator. Then you come off the throttle and she dives. This is why a lot of guys crash on landing. It's worth the work required to get it right.

Vinnie
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Old Jan 25, 2011, 05:47 AM
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The Netherlands, LI, Venray
Joined Dec 2008
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Quote:
Originally Posted by JustGoFly View Post
Hi Jaccies,

If you point below the nose - it will fly nose up, and climb under power. Some power systems are setup that way since they fly easier and better at slow speeds. Try shimming the nose to be more level - not perfectly level. I mount mine lower than your photo and level - but I also have a lot more power so it is pushing right on the thrust line 90 degrees to the thrust line. I do this for Strykers, Projeti's and get alot more speed and rock solid control. You should be able to toss between full power and off and the nose should not dip or climb. It should remain rock steady. Do this test until you get the angle perfect.

A simple test we do is to trim the Jet to fly level at 1/2 throttle. Then fly by level and as it passes - gun the throttle and see if it climbs or dives. Climb = Shim motor back down a little, Dive=shim the motor back up a little.

Note - the opposite happens when you land. If it climbs under power - you are holding the nose down with elevator. Then you come off the throttle and she dives. This is why a lot of guys crash on landing. It's worth the work required to get it right.

Vinnie
Thanks Vinnie,

not 100% clear, I dont understand here what is the thrust line, is there a picture that makes it more clear ? Should thrustline go through the COG point?

You say, Climb = Shim motor back down a little, Dive=shim the motor back up a little.
Do i understand it right see the color lines on my picture
thanks
Jac
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Last edited by jaccies; Jan 25, 2011 at 05:54 AM.
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Old Jan 25, 2011, 12:20 PM
BLANIK213
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United States, NY, Phoenicia
Joined Feb 2008
665 Posts
Jaccies,you are correct in your understanding of the thrust line adjustment explained by Vinnie.Once you get used to the brushed system you will be looking for more speed and JustGoFly has all the necessary brush less upgrades for the task including a better motor mount system.
Hey Vinnie just saw that Projeti vs FJ video looks like you guys had a great time even though it cost a FJ.How fast is your TJ with the 550th's on board and 4s?
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Old Jan 25, 2011, 02:03 PM
just Some Useless Geek
Chicagoland
Joined Oct 2008
2,544 Posts
Hey, jaccies? Another potential assistance is your radio. If you have a computer radio with programmable mixers you can dial in some elevator trimming in proportion to the throttle. So, if you still have a problem with pitch change on throttle change (it's hard to get it just right) then you might dial up a mix that puts in some elevator correction when you change the throttle. That way the plane stays level at any power setting.

I had to do that recently with a PrimeJet8 that another guy built for me to test out. I had the motor mounted way wrong and had to dial up the mixer just to fly the thing without constantly leaning on the flightstick. After I got the motor thrust angle sorted out I eliminated the throttle->elevator mix.
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Old Jan 25, 2011, 09:46 PM
Rochester, NY
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United States, NY, Monroe
Joined May 2004
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Jaccies - if you move the motor 90 degrees to the BLUE line that you drew, you are pointer further below the nose - lifting the nose, and causing the plane to CLIMB under power. This is the same as LIFTING the rear end of the motor. Make sense ?

If I understand your drawing the blue line that shows DIVE will actually cause the plane to climb more. Setting up to the blue line will make the problem worse.

The thrust line is the imaginary line through the fuselage that is the balance point. Typically right down the center of the fuselage. Many pusher motors will mount above the thrust line and point the axle just below the tip of the nose. The lower you point below the tip the more the plane will climb under power.

I've tried mixing in aileron throws to throttle for a funjet. Seems the funjet is extremely sensitive to torque and it makes the plane roll under full power. But that is extremely difficult to setup properly because full throttle when the plane is moving slow is not the same torque as full throttle at full speed. I prefer working on getting the motor angle correct.

I have some L mounts that I put screws in to a hard mount. Fly - adjust - fly adjust until it's perfect. It may not be ideal for your can motors, but I do think shimming the back end down a bit will reduce the amount the plane climbs.

Woodie we hit 154 on the FunJet in a steep dive. It's typically 130 on 4S.
Check out the video here:
http://www.rcgroups.com/forums/showthread.php?t=1374316

Enjoy,
Vinnie
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Last edited by JustGoFly; Jan 25, 2011 at 10:26 PM.
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Old Jan 26, 2011, 12:30 AM
just Some Useless Geek
Chicagoland
Joined Oct 2008
2,544 Posts
Hmm...torque roll. I hadn't considered that. Of course, if you are having problems getting the plane to handle in the first place then you probby aren't hitting the throttle hard enough to raise additional grief by introducing torque-related symptoms. Bringing the throttle on a little slower will ameliorate the problems associated with torque roll for the most part.

Naturally, the real solution is the get the motor(s) aligned properly. The elevon mixing trick is just a stopgap while you get the real issues squared away.
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Old Jan 26, 2011, 12:58 AM
Rochester, NY
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United States, NY, Monroe
Joined May 2004
1,883 Posts
Quote:
Originally Posted by A Useless Geek View Post
Hmm...torque roll. I hadn't considered that. Of course, if you are having problems getting the plane to handle in the first place then you probby aren't hitting the throttle hard enough to raise additional grief by introducing torque-related symptoms. Bringing the throttle on a little slower will ameliorate the problems associated with torque roll for the most part.

Naturally, the real solution is the get the motor(s) aligned properly. The elevon mixing trick is just a stopgap while you get the real issues squared away.
The torque roll is on the FunJet - I haven't had a problem with the TwinJet. I agree alignment of the motors is key to a great flying plane and often overlooked. As for hitting the throttle hard enough - I've always wondered why we need a variable stick for throttle. It should go on full throttle as soon as you plug in a battery The torque problem we had with FunJet was it would fly perfect at half throttle, but at full throttle it would pull crazy hard to the left. We added weight to the right wing which helped, I guess this is a known issue. I still think it's due to the horizontal motor angle. There was no adjustment built into the mount.

I still think the TwinJet is a much better flyer than the FunJet. It flys more precisely, lands easier and looks better. But the FunJet needs only one motor to achieve killer speed. Actually the Projeti kicks both Jets a$$ !

Vinnie
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