Notices
RC Gliders, Sailplanes and Slope Soaring Discuss rc gliders,rc sailplanes and slope soaring in this forum. Thermaling techniques, airfoils, tips, etc

Nodd's Great Planes Spectra

Old 06-10-2014, 10:25 AM
  #51  
davevh
Member
 
Join Date: May 2006
Location: Cape Town, South Africa
Posts: 93
Likes: 0
Received 0 Likes on 0 Posts
Default

Interesting, I have not experienced that moisture problem before, thanks for clearing that mystery up!

Heh, HD or 4K? :-)

I actually used a fixed prop on the first few flights on the Gentle Lady above (folding prop I ordered via tower would not work with the shaft of the Park 480, its one of those APC doodads which does not seem to fit any regular shaft out there).
I know what you mean about making passes with the prop, I was stupid enough to have the brake disabled which made it that much more fun to line it up horizontal to the ground

I think its great (no pun intended) that you resurected this bird and did such a good job with it. Onto the maiden, and its report Sir!

Last edited by davevh; 06-10-2014 at 10:27 AM.
Old 06-24-2014, 10:37 PM
  #52  
Nodd
Thread Starter
 
Nodd's Avatar
 
Join Date: Feb 2012
Location: Fairfield, CT
Posts: 416
Likes: 0
Received 0 Likes on 0 Posts
Default

MAIDEN FLIGHT VIDEO
Well here we go, it's time to see if this will fly...


http://youtu.be/Wf1u4p4p1uU
Old 06-25-2014, 02:31 AM
  #53  
davevh
Member
 
Join Date: May 2006
Location: Cape Town, South Africa
Posts: 93
Likes: 0
Received 0 Likes on 0 Posts
Default

Hey Chris, big congrats on the successful maiden

I really enjoyed the video, thanks for taking the time to make it. It was especially cool having those pics of you when younger and seeing some of those older time gliders, brought back memories (I was quite a bit younger at that time, in the 80's I would have been less than 10, but good memories of the flying clubs with many poly wings in Johannesburg growing up).

Flying these planes really brings us back to the pure basics, and I admit that when flying this past Saturday with my GL and catching some light winter lift, staying up 1/2 hr or more, gave me such nostalgic enjoyment that it was the most fun I have had in RC in ages!
Only thing that sux is I cant stay up much longer due to neck pain. My GL also hates wind so I can only fly on very calm days (rudder has problems overcoming sudden wing dips, think its the small rudder).

One thing I must mention is PLEASE be careful when handling the glider when electrics are hot! In the video when you picked it up after landing you were holding the nose towards you with the prop very close to your forearm (that how it looked anyway). If you just bump the throttle (or have a glitch), I cringe to think what may happen.
I make it practice to lift the bird up from behind with a firm grip around the nose, or if I am going to re-launch I place my hand under the back of the wing under the fuse. In past experience I have had motors go full bore and had some very near strikes, and learned from those near catastrophic incidences (I was very lucky). I have disciplined myself to always think what may happen if the motor goes hot, and what it may strike. Sorry to harp on, but I would hate to see you hurt.

Enjoy the fun new bird.

Dave
Old 06-25-2014, 06:57 PM
  #54  
Nodd
Thread Starter
 
Nodd's Avatar
 
Join Date: Feb 2012
Location: Fairfield, CT
Posts: 416
Likes: 0
Received 0 Likes on 0 Posts
Default

That's excellent advice no doubt, that big folding prop will bite ya if you don't respect it. In my defence I use a throttle kill switch on my radio. That prevents the motor from turning in the event the throttle stick is inadvertently moved or bumped. I also employ both a throttle warning when turning the radio on & a switch warning that prevents the radio from booting-up until the throttle kill switch is engaged. You may also notice that while I may place my arm in the prop's arc temporarily while picking up the plane, I immediately turn the plane some so my arm is clear. At least that's what I generally do. I could take it a step further & do as you suggest, handle the plane from behind the wing only & I do just that fairly frequently too.

That said though, glitches happen, something distracts you, it only takes an instant for things to get gory. Better to be safe than sorry, thanks for the reminder.

I totally know what you mean about the nostalgia a plane like this can generate. Of course you need to have flown these in the past for that to work but even without that, they really are fun to fly. I especially like the way a rudder only polyhedral sorta lumbers its way into a turn. It's not an immediate response like you get from ailerons. There's a subtle delay, almost like the plane is thinking about it before it decides if actually wants to make a turn. You sorta need to plan ahead a little, especially around trees etc. I'd almost forgotten that about these old gals. Of course that delayed response is not quite as much fun when there's a good breeze blowing, as you mentioned. I have other birds I can fly when it's blowing though.

Anyway, looking forward to spending some quality stick time reacquainting myself with this style of flying. Fun fun!
Old 06-26-2014, 07:12 AM
  #55  
soarrich
My Feedback: (98)
 
soarrich's Avatar
 
Join Date: Feb 2002
Location: The Villages, Florida NJ
Posts: 4,677
Likes: 0
Received 0 Likes on 0 Posts
Default

Chris

Did I hear you say you had DOWN mix in with the spoilers? With the spoilers located where you did the plane should already pitch down with spoiler deployment.
Old 06-26-2014, 09:38 AM
  #56  
Nodd
Thread Starter
 
Nodd's Avatar
 
Join Date: Feb 2012
Location: Fairfield, CT
Posts: 416
Likes: 0
Received 0 Likes on 0 Posts
Default

Here's my understanding of how spoilers (or flaps) affect an aircraft's pitch...



From my deluxe diagram you can see how increasing the wing's drag either above or below the CG will cause the plane to pitch up or down. The Spectra's wing is mounted atop the fuselage slightly above the CG so I programmed down elevator to compensate. I over did it however, the wing is only very slightly above the CG on this model so needed very little compensation.

Last edited by Nodd; 06-26-2014 at 10:12 AM.
Old 06-26-2014, 10:05 AM
  #57  
longsoar
 
longsoar's Avatar
 
Join Date: Mar 2012
Location: East Stroudsburg, PA
Posts: 220
Likes: 0
Received 0 Likes on 0 Posts
Default

Chris,
It is only partially true. Mostly moment depends on airfoil design, Reynolds number and many other aspects. I have seen neutral response where pitch-up was expected and vise-versa.
The same goes for flaps. On full scale we usually see nose-down tendency while in RC - an opposite nose-up response.
I think mostly it depends on a Reynolds number. For example flaps or dive brakes wont matter much on a house fly wing.
Also, dive brakes momentum depends on position on a airfoil chord. Further back reduces dive tendency, but then again it depends on a wing focus.
A lot of focus changed with leading edge slots, flaps and air brakes besides changing the whole aerodynamics, which in-turn may change aircraft responsiveness, controllability and ability to stay in the air.
All I am trying to say, response to a dive brakes is not a simple follow-up on a chart, it's a combination of factors.
Cheers,
Mark
Old 06-26-2014, 10:48 AM
  #58  
aeajr
My Feedback: (2)
 
aeajr's Avatar
 
Join Date: Jan 2003
Location: Long Island, NY
Posts: 8,573
Likes: 0
Received 11 Likes on 11 Posts
Default

I have never had spoilers cause pitch up on any RES glider I have owned. All were located in front of or very near to the CG and they all caused a reduction in lift causing a drop in the nose. For some, like my Spirit, the drop was mild. My AVA is kind of medium in this regard. Without some up they would pick up speed as they started to drop the nose. On my Sagitta 600 the spoilers would induce a sudden drop leading to a dive if I did not add up elevator compensation right away.

Note that all of those had barn door type spoilers where a hinged section would raise at the rear and create an angled ramp that would spoil the lift and which seem to create an aerodynamic down force on the wing. The photo below of my Sagitta 600 shows an example of barn door spoilers.


Blades that come straight up, what I normally think of as air brakes, are different. They create a barrier to the air flow, which also spoils the lift but which may not create a significant down force as a barn door type spoiler would. In this case you might get a nose rise from a torque around the CG. I have never owned a glider with this type of spoiler/air brake so I can't speak from experience. The Hobbyking spoiler would be an example of a vertical blade airbrake/spoiler
http://www.hobbyking.com/hobbyking/s...Left_Side.html


Spoilerons, on the other hand, which are not spoilers but trailing edge being raised, can cause a pitch up as the force on the surface is behind the CG. My Easy Glider would demonstrate this characteristic. Whether I invoked flapperons or spoilerons I had to add down elevator compensation to maintain level flight.
Attached Thumbnails Click image for larger version

Name:	Front view with spoilers up.JPG
Views:	158
Size:	54.6 KB
ID:	2008936  

Last edited by aeajr; 06-26-2014 at 11:03 AM.
Old 06-26-2014, 11:13 AM
  #59  
davevh
Member
 
Join Date: May 2006
Location: Cape Town, South Africa
Posts: 93
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by aeajr
I have never had spoilers cause pitch up on any RES glider I have owned. All were located in front of or very near to the CG and they all caused a reduction in lift causing a drop in the nose. For some, like my Spirit, the drop was mild. My AVA is kind of medium in this regard. Without some up they would pick up speed as they started to drop the nose. On my Sagitta 600 the spoilers would induce a sudden drop leading to a dive if I did not add up elevator compensation right away.

Note that all of those had barn door type spoilers where a hinged section would raise at the rear and create an angled ramp that would spoil the lift and which seem to create an aerodynamic down force on the wing. The photo below of my Sagitta 600 shows an example of barn door spoilers.


Blades that come straight up, what I normally think of as air brakes, are different. They create a barrier to the air flow, which also spoils the lift but which may not create a significant down force as a barn door type spoiler would. In this case you might get a nose rise from a torque around the CG. I have never owned a glider with this type of spoiler/air brake so I can't speak from experience. The Hobbyking spoiler would be an example of a vertical blade airbrake/spoiler
http://www.hobbyking.com/hobbyking/s...Left_Side.html



Spoilerons, on the other hand, which are not spoilers but trailing edge being raised, can cause a pitch up as the force on the surface is behind the CG. My Easy Glider would demonstrate this characteristic. Whether I invoked flapperons or spoilerons I had to add down elevator compensation to maintain level flight.
From what I recall, the blade type spoilers used to cause a nose up pitch in the K13 glider I trained on many years ago. This throws something a little different into the mix as they deployed on top of, as well as below, the wing.
See here:
http://en.wikipedia.org/wiki/File:K13_glider.jpg
In the above picture, its looks like a little down elevator is being fed in which may confirm this.
I would think with equal deployment above and below, that the effects would be neutralised and cause no pitch change, though the airfoil may still cause there to be a pressure differential between the two.

Interesting stuff!

To test this, I say do the obvious Chris. Next time you fly, mix out the elevator and see which way she pitches and report back to us. All in the name of science, and to do the mythbusters proud!

Dave

Last edited by davevh; 06-26-2014 at 11:16 AM.
Old 06-26-2014, 11:19 AM
  #60  
aeajr
My Feedback: (2)
 
aeajr's Avatar
 
Join Date: Jan 2003
Location: Long Island, NY
Posts: 8,573
Likes: 0
Received 11 Likes on 11 Posts
Default

Do your testing at 100 feet, not near the ground.
Old 06-26-2014, 11:24 AM
  #61  
davevh
Member
 
Join Date: May 2006
Location: Cape Town, South Africa
Posts: 93
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by aeajr
Do your testing at 100 feet, not near the ground.
YES, good advice, something I should have mentioned. 3 mistakes high always!
Old 06-27-2014, 06:53 PM
  #62  
soarrich
My Feedback: (98)
 
soarrich's Avatar
 
Join Date: Feb 2002
Location: The Villages, Florida NJ
Posts: 4,677
Likes: 0
Received 0 Likes on 0 Posts
Default

I've built two planes that did not pitch down:
The first was an OLY II that I moved the spoilers an inch back from the main spar, (the hi-point of the wing), it had no pitching.
The second was my design "Dancing Hippo" it had the spoilers at 55% on a AG35 airfoil, the might have a little pitch-up. I liked to thing it just locked in a nice sink rate without any speed up that you normally see on spoiler deployment.
Spoiler deployment doesn't have to cause pitching, but in most cases in the '70s & '80s it caused pitch down.

Just for laughs at 1:43 I let down without spoilers, don't attempt this without lots of CF in the wings If you watch the video 2:35 is what the climb looks like looking back, 6:53 is the side view, and 9:10 you can see that the spoilers don't cause much change in pitch, if any.

https://www.youtube.com/watch?v=y4Jx...4&feature=plcp
Attached Thumbnails Click image for larger version

Name:	Ty65802.jpg
Views:	167
Size:	42.6 KB
ID:	2009378   Click image for larger version

Name:	Yw66332.jpg
Views:	191
Size:	59.6 KB
ID:	2009379   Click image for larger version

Name:	lg-66421.jpg
Views:	134
Size:	17.8 KB
ID:	2009380   Click image for larger version

Name:	Av68757.jpg
Views:	164
Size:	46.3 KB
ID:	2009381  
Old 06-28-2014, 11:07 AM
  #63  
Nodd
Thread Starter
 
Nodd's Avatar
 
Join Date: Feb 2012
Location: Fairfield, CT
Posts: 416
Likes: 0
Received 0 Likes on 0 Posts
Default

The second flight that day I reduced my spoiler > elevator compensation, problem solved.

I've found the high-wing, mid-wing, low-wing, pitch rule is usually right-on for flaps. I'd assumed the same would apply to spoilers but apparently there's more to it. Nevertheless I think that rule is a good place to start & as always, practice "landing in the sky" while still up high to see how she reacts.

I took the Spectra to a giant scale aerotow event last weekend & flew her some after we were done towing. Got a chance to fly with Paul Naton from RadioCarbon Arts. That was a real treat & I was impressed at how well my Spectra performed next to Paul's rather expensive DLG. Gotta love these old wooden ships, they really do fly very nicely.
Old 06-28-2014, 12:25 PM
  #64  
aeajr
My Feedback: (2)
 
aeajr's Avatar
 
Join Date: Jan 2003
Location: Long Island, NY
Posts: 8,573
Likes: 0
Received 11 Likes on 11 Posts
Default

Well I also had a joyful day of flying today. My friend built me a bubble dancer. This is the third or 4th he has built and this was by far the best. The weather was perfect and the Bubble Dancer, true to its heritage was like a think of beauty to behold. Wonderful.

36 ounces all up. No where near the 31 oz of Dr. Drela's but it flew wonderfully just the same.

Last edited by aeajr; 07-29-2014 at 01:43 PM.
Old 07-29-2014, 01:44 PM
  #65  
aeajr
My Feedback: (2)
 
aeajr's Avatar
 
Join Date: Jan 2003
Location: Long Island, NY
Posts: 8,573
Likes: 0
Received 11 Likes on 11 Posts
Default

Originally Posted by Nodd
The second flight that day I reduced my spoiler > elevator compensation, problem solved.

I've found the high-wing, mid-wing, low-wing, pitch rule is usually right-on for flaps. I'd assumed the same would apply to spoilers but apparently there's more to it. Nevertheless I think that rule is a good place to start & as always, practice "landing in the sky" while still up high to see how she reacts.

I took the Spectra to a giant scale aerotow event last weekend & flew her some after we were done towing. Got a chance to fly with Paul Naton from RadioCarbon Arts. That was a real treat & I was impressed at how well my Spectra performed next to Paul's rather expensive DLG. Gotta love these old wooden ships, they really do fly very nicely.
How is your Spectra doing?

One of our club members flew his in a club ALES contest. I won with my e-Supra but he was only a few points behind me and ahead of the guy flying the Xplorer 3.8M
Old 07-29-2014, 03:53 PM
  #66  
Nodd
Thread Starter
 
Nodd's Avatar
 
Join Date: Feb 2012
Location: Fairfield, CT
Posts: 416
Likes: 0
Received 0 Likes on 0 Posts
Default

While I've never flown a Bubble Dancer I've studied its design extensively, especially the wing-spar. I imagine it's a real treat to fly.

That's pretty impressive to hear a Spectra did so well, the guy with the Xplorer couldn't have been happy LOL. Congrats on the first place finish.

My kit-bashed Spectra is still going strong, I've been flying it weekly for a while now. I'm not really into competition although we do mess around with a little ALES action on occasion. For the most part though, we just follow each other around looking for lift. The Spectra hangs in there just fine with the EasyGliders, Radians, Calypsos etc. We also have quite a few guys flying other old polyhedral woodies. Since I'm one of the few guys with a variometer, I often find them bugging me to go find the lift, especially when it's one of those mostly sink days. It's funny they complain about my "Nintendo" radio beeping away but when there's no lift to be found, they're all of a sudden all into it LOL.

Tomorrow is flying day, the weather looks awesome! Fairly chilly tonight, tomorrow will be 78, 6 mph winds & sunny. Sounds like thermals to me! Inbetween running my aerotow tug, flinging my DLG & screwing around with my new tri-copter, I'll be spending several hours on the Spectra for sure.
Old 07-29-2014, 06:23 PM
  #67  
ejett
Senior Member
My Feedback: (4)
 
ejett's Avatar
 
Join Date: Dec 2002
Location: Athens, LA
Posts: 232
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by soarrich
I've built two planes that did not pitch down:
The first was an OLY II that I moved the spoilers an inch back from the main spar, (the hi-point of the wing), it had no pitching.
The second was my design "Dancing Hippo" it had the spoilers at 55% on a AG35 airfoil, the might have a little pitch-up. I liked to thing it just locked in a nice sink rate without any speed up that you normally see on spoiler deployment.
Spoiler deployment doesn't have to cause pitching, but in most cases in the '70s & '80s it caused pitch down.

Just for laughs at 1:43 I let down without spoilers, don't attempt this without lots of CF in the wings If you watch the video 2:35 is what the climb looks like looking back, 6:53 is the side view, and 9:10 you can see that the spoilers don't cause much change in pitch, if any.

https://www.youtube.com/watch?v=y4Jx...4&feature=plcp

Rich, just now reading this thread. I think I've seen this plane before but I forget exactly what it is. How about refreshing my memory on that.

Ed
Old 07-29-2014, 08:16 PM
  #68  
soarrich
My Feedback: (98)
 
soarrich's Avatar
 
Join Date: Feb 2002
Location: The Villages, Florida NJ
Posts: 4,677
Likes: 0
Received 0 Likes on 0 Posts
Default

ejett

I love the BubbleDancer, but it's complicated and it wasn't my design so I came up with the Dancing Hippo. I did a thread on it when I built it 5~6 years ago, either on RCU or RCGroups. I used CF tube spars, an AG35 airfoil on the center panel and Ag35 to AG37 on the tips. I like stab and elevator rather than a flying stab, put the spoilers out past the stab so the spoilers don't mess up the flow over the stab. The wing can't be broken on a winch, I launched so hard into a 22kt headwind that the outer panels where vertical. I used a BD pod and boom for the fuse. I flown it in two contest, it won the first contest, the second the wind was 22kts so it wasn't it's day. I don't do contest anymore so I put a motor in it, I usually fly about one hour, most times I get that with one climb, sometimes two, it has 6 cell 2200 mah batteries, the batteries are good for about 8 climbs.
Old 08-08-2014, 11:49 AM
  #69  
Indy Park Flyer
 
Indy Park Flyer's Avatar
 
Join Date: Jan 2006
Location: Mooresville, IN
Posts: 111
Likes: 0
Received 0 Likes on 0 Posts
Default

I picked up a Spectra last week and I plan to change out the motor and go brushless. It looks like you used a Turnigy motor, but would you mind sharing your power setup?
Thanks,
Indyparkflyer
Old 08-08-2014, 03:31 PM
  #70  
Nodd
Thread Starter
 
Nodd's Avatar
 
Join Date: Feb 2012
Location: Fairfield, CT
Posts: 416
Likes: 0
Received 0 Likes on 0 Posts
Default

Yeah totally ditch that old brushed motor & get some new gear in there. These old gliders fly awesome with modern guts.

I did actually list my setup back in post #47 but here's that info again...





I really like the Turnigy SK3 line of motors. They're a little more money than the other motors but the added performance is worth it. I was worried a dinky 28mm motor wasn't going to cut it for a seven foot glider but she climbs very nicely with this setup. Not balistic but equal if not better than most of the other guys I fly with.

Best of luck with your conversion.
Old 08-14-2014, 08:32 AM
  #71  
davevh
Member
 
Join Date: May 2006
Location: Cape Town, South Africa
Posts: 93
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by Nodd
Yeah totally ditch that old brushed motor & get some new gear in there. These old gliders fly awesome with modern guts.

I did actually list my setup back in post #47 but here's that info again...





I really like the Turnigy SK3 line of motors. They're a little more money than the other motors but the added performance is worth it. I was worried a dinky 28mm motor wasn't going to cut it for a seven foot glider but she climbs very nicely with this setup. Not balistic but equal if not better than most of the other guys I fly with.

Best of luck with your conversion.
Hi Chris

Where did you get the aluminium APC hub from, and what size is the shaft hole?
I ordered an APC 11X8 set from Tower Hobbies some time ago, but never got to use it since the blades come with a useless composite hub with non-standard 8mm prop size hole (I wanted it for a Eflite Park 480 which has a 4mm shaft, with the included 6mm prop adaptor).
The blades are nice, I would love to be able to use them (and no, I can't use a filler tube for the 2mm difference with the stock hub, since no store in South Africa stocks one the right size).

Thanks!
Dave
Old 08-14-2014, 10:02 AM
  #72  
Nodd
Thread Starter
 
Nodd's Avatar
 
Join Date: Feb 2012
Location: Fairfield, CT
Posts: 416
Likes: 0
Received 0 Likes on 0 Posts
Default

I believe I used a MPI folding propeller hub & spinner (follow link then scroll down some).
Old 08-14-2014, 12:53 PM
  #73  
davevh
Member
 
Join Date: May 2006
Location: Cape Town, South Africa
Posts: 93
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by Nodd
I believe I used a MPI folding propeller hub & spinner (follow link then scroll down some).
Got it, thank you!
Old 01-22-2024, 01:43 PM
  #74  
ChipChip
Junior Member
 
Join Date: Jan 2024
Posts: 1
Likes: 0
Received 0 Likes on 0 Posts
Default

Hi Chris , I cant see the images on your thread
Regards
Chip
Old 01-22-2024, 02:33 PM
  #75  
Nodd
Thread Starter
 
Nodd's Avatar
 
Join Date: Feb 2012
Location: Fairfield, CT
Posts: 416
Likes: 0
Received 0 Likes on 0 Posts
Default

Yeap. This thread was created back in 2014 before https was implemented. When it was, RCUniverse no longer allowed links to images hosted at regular http websites. Sorry but I'm probably not going to bother fixing this as this thread is rather old now.

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.