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

Inducing & recovering spins with sailplanes

Reply
Old 08-01-2004, 04:12 AM
  #1
luvbus
Thread Starter
 
Join Date: Jul 2004
Location: Beverley, UNITED KINGDOM
Posts: 21
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default Inducing & recovering spins with sailplanes

Hi,

I am looking for some info on spinning & recovering from spins with sailplanes,

I have done searches on the net and have mostly come up on info on flat spins with 3D pattern flying, not quite what I had in mind!

If I have pieced the bits together correctly to induce a spin you keep nosing up until you stall, watch which wing starts to drop then turn the rudder in that direction.

Recovery involves centering the sticks and the applying rudder in the opposit direction to the spin, then pulling out when the rotation stops.

My gliders do not seem to drop a wing when stalled, does applying rudder in one direction or the other 'force' the spin?

Do you need to do anything different with gliders as opposed to powered aircraft?

Does a v-tail have any effect on techniques?

Any help would be appreciated, thanks in advance,

Rich
luvbus is offline  
Reply With Quote
Old 08-01-2004, 09:48 AM
  #2
Rick K
 
Join Date: Nov 2003
Location: Fontana, CA
Posts: 259
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Inducing & recovering spins with sailplanes

Hi Rich, How I do it (with 2/3ch poly planes ) : Full up elevator with full R or L rudder and hold for the spin . . . To recover just 'neutralize' the stick(s) Plane will flop into a slightly nose-down but 'flat' tight, rapidly desending spin and after neutralizing the stick will recover in less than one turn. This is a great way to lose altitude quickly but only enter the spin from a fairly high alitutude . . . the plane sinks like a brick and each plane at different rates of desent and recovery. Be prepared to apply op. rudder if the plane doesn't recover within two turns. This assumes we're talking of polydihidrel planes, I don't know if it'd work the same with straight wings and I don't know if 'V' tails react the same. I guess this covers most of your questions except the power part. The difference is with sailplanes is that they, at least thermal sport ones, is that they're very stable . .. . they need to be forced and held into a spin and. . . you'd better plan to come out of the spin in a place/area and with enough air left under ya where your'e going to be able to set up for a landing pattern, you can't drive a sailplane over to the approach area, the 'thermal gods' might be busy elsewhere. The first time start 'way' high and only go a few turns before you recover . . . it'll leave you time to try plans 'b' or 'C' if 'A' doesn't work.
Rick K
Rick K is offline  
Reply With Quote
Old 08-01-2004, 04:10 PM
  #3
luvbus
Thread Starter
 
Join Date: Jul 2004
Location: Beverley, UNITED KINGDOM
Posts: 21
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Inducing & recovering spins with sailplanes

Thanks for the reply Rick,

I suppose I really need to get out there & give it a go!

The gliders I am flying are relatively flat winged ( Highlight & Banana ) but I am sure the techniques will work just the same, if a little less stable than a polydihidral.

I have both a sailplane & electric fuz for the Banana so I am tempted to try things out first on the electric first so I can have a go in clear air from a really good height to get the hang of things!

Thanks again for the help,

Rich
luvbus is offline  
Reply With Quote
Old 08-03-2004, 04:42 AM
  #4
luvbus
Thread Starter
 
Join Date: Jul 2004
Location: Beverley, UNITED KINGDOM
Posts: 21
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Inducing & recovering spins with sailplanes

Well I went out & tried spinning the e-banana but it didn't seem to want to play!

I waited for the stall, threw in full rudder and it just went into a wide high speed spiral dive (spiral was about 50' dia). It was quite impressive and the plane really 'howled' on the way down but was not the tight fluttering spin I was expecting.

I did a bit of experimenting, putting the rudder to max travel, moving the C of G right back but it did not make any difference to the spin.

I think the v-tail must have something to do with this as the rudder is not true rudder but a mix of elevator & rudder.

Anyone out there with any thoughts?

Cheers Rich
luvbus is offline  
Reply With Quote
Old 08-03-2004, 07:31 PM
  #5
flybaby101
 
Join Date: Feb 2003
Location: Devonporttasmania, AUSTRALIA
Posts: 80
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Inducing & recovering spins with sailplanes

man ths is easy ,

1. pull full direction of spin

2.wait for spiral

3. little bits oF up elevator until spin is acheived

4. oppisite rudder and level out

if this doesnt work try a dsing trick which is to stall , then apply full rudder during the stall , most v-tail models react this way.

cheers
dug[&:]
flybaby101 is offline  
Reply With Quote
Old 08-04-2004, 03:10 AM
  #6
luvbus
Thread Starter
 
Join Date: Jul 2004
Location: Beverley, UNITED KINGDOM
Posts: 21
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Inducing & recovering spins with sailplanes

Thanks fore the reply Dug,

Things must have moved on in DSing if you are now throwing in spins in the middle of those high speed passes! lol!

The DSing technique you have described is exactly the approach I have been trying but the result has always been the open spiralling dive.

A reply I got from another forum suggesting the small elevator/rudder throws you get with a moulded glider may not be enough to induce a spin, but if you can easily achieve them with the very small throws associatd with DSing this is obviously not the problem!

The same forum suggested as the v-tail rudder uses a componant of down elevator when you use the rudder this may be preventing the spin from developing properley!

Any thoughts on the above would be appreciated.

Please tell me if I have the other technique you described right:-

Flying along slowly you apply full rudder in the direction of spin you want before the stall to cause a tight yaw turn, then add up elevator ( small amounts ) until the spin starts and keep doing the same to keep the spin going?

This sounds reasonable I will give it a go!

Cheers

Rich [:@]
luvbus is offline  
Reply With Quote
Old 08-04-2004, 04:05 AM
  #7
flybaby101
 
Join Date: Feb 2003
Location: Devonporttasmania, AUSTRALIA
Posts: 80
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Inducing & recovering spins with sailplanes

yep ,

and it is a common thing to do a spin in dsing to wash off speed after a run , we dont do this until we have left the dry-air or the dead air so to speak by going into the lift , I have seen one pilot do a high speed run onto a verticial climb here and it was a truly amazing thing to see , since it aint got no engine , its going straight up at least 200ft then into a spiral to decend.

truly amazing

dug[&:]
flybaby101 is offline  
Reply With Quote
Old 08-05-2004, 03:50 PM
  #8
Rick K
 
Join Date: Nov 2003
Location: Fontana, CA
Posts: 259
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Inducing & recovering spins with sailplanes

"DSing"??? Say what? Iv'e never heard of that phrase. What does it mean?
feeling clueless Rick K
Rick K is offline  
Reply With Quote
Old 08-05-2004, 06:21 PM
  #9
flybaby101
 
Join Date: Feb 2003
Location: Devonporttasmania, AUSTRALIA
Posts: 80
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Inducing & recovering spins with sailplanes

Dynamic soaring , you know lil glider doin 200 n stuff , I thought that with your great experience you may of heard about it. Its when you get a glider and fly it in a circuit paralell to the dead air and lift , every circuit gets faster until high speed passes are acheived , the fastest ds run is about 230mph by a guy in northern california , although you need a good epp glider or compisite model to try it , and its dangerous due to the speeds and tightness of the circuit.

cheers
dug[&:]
flybaby101 is offline  
Reply With Quote
Old 08-05-2004, 06:54 PM
  #10
luvbus
Thread Starter
 
Join Date: Jul 2004
Location: Beverley, UNITED KINGDOM
Posts: 21
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Inducing & recovering spins with sailplanes

Hell I thought I was green!!!!!! lol !!!

Would love yo have a go but the local hills here in Yorkshire are not suitable, even had a go on CRRC sim and couldn't get the hang of it on there either!!

Do a google and have a look at the video's, v. fast! and no motor!!

Rich

[:@]
luvbus is offline  
Reply With Quote
Old 08-05-2004, 06:59 PM
  #11
luvbus
Thread Starter
 
Join Date: Jul 2004
Location: Beverley, UNITED KINGDOM
Posts: 21
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Inducing & recovering spins with sailplanes

Still had no luck trying to get a spin Flybaby!!

The closest I have got is using your pre stall rudder technique!

Been doing some flick rolls instead as suggested by another forum.

All glider aerobatic suggestions greatly appreciated ( diagrams even better!! )

Cheers,

Rich
luvbus is offline  
Reply With Quote
Old 08-05-2004, 08:27 PM
  #12
flybaby101
 
Join Date: Feb 2003
Location: Devonporttasmania, AUSTRALIA
Posts: 80
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Inducing & recovering spins with sailplanes

got flaps , put them in an up position at height then try it , but you have to return to neutral before minimum altitude..

cheers
dug[&:]
flybaby101 is offline  
Reply With Quote
Old 08-06-2004, 03:13 AM
  #13
luvbus
Thread Starter
 
Join Date: Jul 2004
Location: Beverley, UNITED KINGDOM
Posts: 21
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Inducing & recovering spins with sailplanes

Got flapperons, I take it they will have the same effect? I will give that a go.

Thanks

Rich
luvbus is offline  
Reply With Quote
Old 08-06-2004, 08:39 AM
  #14
Rick K
 
Join Date: Nov 2003
Location: Fontana, CA
Posts: 259
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Inducing & recovering spins with sailplanes

Now I understand, being mainly a thermal type of guy I'm not really into 'slope' acronyms but am familiar with the concept of dynamic soaring. Just never heard it abbreviated like that . . . Maybe I'm more 'Old-School' than I thought, a little more out of the 'loop' than I think. Well that's what happens when you become late middle aged I guess. Heck, besides my kids (grade school age) I don't know anyone well younger than thrity-two (wife) Humm, DSing . . . one of the times I did go sloping around ten years ago, I think that's what my sloper friend was instructing me to do, sounds like it anyway. Thanks for cluing me in.
Rick K
Rick K is offline  
Reply With Quote
Old 08-06-2004, 12:59 PM
  #15
1fish
 
1fish's Avatar
 
Join Date: Feb 2004
Location: RSM, CA
Posts: 157
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Inducing & recovering spins with sailplanes

The location of your CG and amount of total throw on your control surfaces has a lot to do with the way your plane will flat spin, some planes will spin better inverted and others right side up a lot has to do with the location of the wing in relation to the fuse (mid-wing, low-wing, top-wing) start out by trying a little more rearward CG and a lot more throw, see where this takes you, good luck...
1fish is offline  
Reply With Quote
Old 08-06-2004, 04:31 PM
  #16
luvbus
Thread Starter
 
Join Date: Jul 2004
Location: Beverley, UNITED KINGDOM
Posts: 21
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Inducing & recovering spins with sailplanes

Thanks for the reply,

Moving the C of G Back and increasing the throws was one of the first things I tried.

The C of G was already behind the recommended position to start with. The elevator throw is 5mm, any more than that and the elevator stalls and skids out, even so I did try using a much bigger throw just to try & make it spin but it didn't help! ( made the plane do some great flick rolls though!! ) the rudder throws are the maximum possible about 15mm either way.

The plane I have been using is a Baudis Banana which is a typical 60" molded jobbie, the only departure from the norm is a shorter tail boom than normal. I have both an electric & slope fuz for it and have been trying to/get the hang off spinning the electric one before moving onto the slope so I have the benefit of a quick climb back to altitude after each attempt.

I am going to try flybabys tip of putting some reflex on the wing to see if that helps, if it doesn't i'll try some down flap to see if that makes a difference.

I am at the point of giving up as I don't seem to be getting anywhere, I may have to go up to the slope and try the slope fuz or my Highlight to see if I do any better with those.

Still looking for tips if you have any.

Cheers,

Rich.
luvbus is offline  
Reply With Quote
Reply


Thread Tools
Search this Thread
Display Modes

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



All times are GMT -8. The time now is 10:57 AM.