F106A

My Feedback: (2)

Hi,
When I was flying gliders 30+ years ago there was an even mix of V tails and conventional tails.
Looking over the available gliders I've noticed that the number of conventional tailed models FAR exceed the V tail gliders and was wondering why. The V tail seems to have many advantages but they're pretty scarce.

Also, I never saw a glider with flaps, we used spoilers so I'm interested in knowing why you would want flaps instead of spoilers.
Anyone have any experience with the PULSAR 3.6E RES?
Thanks,
Jon

hattend

My Feedback: (20)

With flaps you can fiddle with the camber for different flight modes. Slight down for launch and slow thermalling, reflexed for high speed travel, normal and full down for landing. Spoilers can be open or they can be closed and usually used only for landing.

Combo of the two is called CROW where the flaps go down and ailerons/spoilers go up. Rapidly slows the plane without a big pitch change (once set up correctly)

V-tails work but they aren't as effective in all flight modes as a cruciform tail. I like V-tails because they look cool. They can also be less prone to damage from landing out.

Don

longsoar

I agree with Don. On the top of it I'd like to add - nowdays most RC gliders use fly-by-wire setups.
One can mix-up with amazing accuracy many flight modes for the given airframe. Also pilots can share the settings digitally over the Internet.
I have never flown V-tail myself in over 30+ years. Just did not happen to me. Although I saw many V-tailed hi-performace gliders Today and they do perform as good as X-tail gliders.
Many hi-performace gliders available in both versions and I asked people who own the glider I fly (Graphite 2E) in V-tail variant - they stated it performs identically with X-tail as they own both.
So it's mostly depend on airframe design and less on tail design how glider performs.

Would be interesting to hear other opinions.
Cheers,
Mark

Art ARRO

My Feedback: (5)

Jon,
I too prefer V-tail gliders for their "coolness". They are harder to rig in order to achieve the desired incidence and alignment angles. Hop over the the RC Pylon forum for discussion techniques on V-Tail alignment. Paul Naton's DVD videos also describe the proper setup and control throws for V-tails. They are definately less subject to damage in any off-field landing besides looking cool.
Rgds,
Art ARRO

Soar RC

Yes.Wotchawannaknow?

F106A

My Feedback: (2)

Hi,
I was wondering how it compares with other gliders in the same class.
How's the build and quality, any issues that need addressing?
Any info on setup/mixing/trimming?
Would you buy another, if not, what model would you choose.
Thanks,
Jon

Soar RC

Great flying sailpane over all. Not a realy windy day flyer but will handle 15 kt winds with no problem. She'll do 10 to 12 minutes in dead air (like in the evening) flight after flight from a 200 metre launch.
Top quality,excellent build,no issues to address .Only odd looking bit is the servo to flying stab linkage. The servo arm and stab v-mount horn are 90° to each other and it seems that they should bind and need a swivel joint. In practice with the fairly small amount of throw,it's not an item.
My 3.6 setup:
Motor: MVVS 4.6/840
ESC:Castle Creations Phoenix Edge 75 amp
Spinner: RFM 38mm x 5mm
Power (real in air figures): 500 watts average ,45 amps . Actually lower once under way. See Castle Link log attached
Prop: Aeronuat 16 x 8 folder, above combo gives a 2300 FPM climb rate. Climb rate will vary on angle of climb, it'll show lower when ranging. See RAM graph, it's about a 70° angle average climb
2 Hitec HS-125MG for spoiler servos and 2 Hitec HS-65HB for rudder and elevators
Battery: Thunderpower 2250 mah 3s 70 c lipo
Horizontal stab is set at 27 mm from leading edge to boom at neutral. This measurement helps when setting up the full flying stab linkage
Throws :12 mm up and down on horizontal stab, 45 mm left and right on rudder, spoilers-full ( about 85°)
CG is set 102mm aft the leading edge
AUW is 62 oz. With 1250 sq.in. this gives a 7.2 oz/sq.ft wing loading.
I use no mixing. Some like to add elevator mix to throttle but I prefer my thumb, just me.

If you use this motor,program your ESC to 25° timing or as far as you can for full power. Also,with the Edge ESC set the throttle with the throttle stick first to get the end points set. This is only a problem if you use a switch for the motor for off/on control. I have mine setup with motor on a switch (Hitec A-9) and the motor is further controlled with a Soaring Circuit CAM altitude switch. I put the spoilers on the throttle stick so I have full proportional control. Whether you go up for deployed and back for retracted (like me) or the other way is your preference.[TABLE="class: invoice-detail, width: 772"]
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Yes, I have three. However I did just buy a 4 metre Kennedy Composites Longhorn which is just a rebadged Super AVA Pro. Only and I mean the only reason I jumped ship from the Pulsars is that they don't make a 4 metre RES. I was in line for a 4 metre Pulsar full house until I learned a RES 4M AVA was available. I prefer the simplicity (no wing wires to plug in and lots of servos) plus 95 % of my flying is for fun. A two hour flight at 2500 feet is a bit less tedious with the more stable RES setup. The 3.6 Pulsar will hold her own at a ALES contest, if I'm paying attention.

Hope this helps you. If you have any other question just fire away.

F106A

My Feedback: (2)

Thanks for the info, I really appreciate it.
I've been flying jets for the last 12 years and looking forward to some relaxing flying for a change.
Is there any advantage of using a geared motor versus a direct drive? Seems people are using both.
Also, is Castle a better ESC (more features) than the Jeti. Seems like the Jeti is used on high end models and Castles arte used on everything else.
Thanks again,
Jon

Art ARRO

My Feedback: (5)

Jon,
You'll enjoy some relaxing flying with sailplanes as compared to jets. I fly both, with jets from May-Oct and sailplanes from Nov-Apr. My biggest hurdle is finding a local sailplane-friendly field and I'm currently flying on a converted cow pasture. E-power is the way to go without the hassle of a high start or winch.
All of my E-sailplanes are direct drive in-runners although I understand you can swing a bigger prop with a gear box. My sailplane ESC's are all Castle for ease of programming- brakeon/off, soft start, etc.
There's a lot of lnfo available here on this forum plus Paul Naton's Radio Carbon ART series of videos. Send me a PM with a mailing address if you wish to borrow some these DVDs.
Rgds,
Art ARRO

aeajr

My Feedback: (2)

GLIDE PATH CONTROLS


First, lets make sure we are using the same terms.

Spoilers and Spoilerons

Spoilers sit on top of the wing, typically near the spar.

Spoilers will reduce lift while inducing drag, but their primary value is not as brakes but as lift reducers. This raises the stall speed, the speed at which the wing can no longer produce enough lift to support the aircraft. So the wing will stall at a higher speed. Some rise like barn doors. This is what we typically call spoilers. Some come straight up like a blade. These we often call air brakes.

When spoilers are deployed typically the nose will drop, due to reduced lift, and we compensate with some up elevator to keep the glider from going into a dive. The best effect is that the glider remains fairly flat but the sink rate is raised so it comes down more quickly but without gaining a lot of speed.


Spoilerons are trailing edge devices that go up. This might be based on ailerons, full span ailerons, flaps or flaps and ailerons in combination. Spoilerons will reduce camber, reducing lift. Think of this as raising the trailing edge like an aileron but on both sides at once.

The wind hits the raised trailing edge and and induces a pressure down at the trailing edge of the wing. Whether you think of it as induced down force or reduction of lift the effect is the same. When done on both wings at the same time this often induces a rise in angle of attack, it picks up the nose since the down force is behind the CG. This may require some down elevator compensation to keep the glider from stalling.

Spoilerons induce drag as you raise them but their primary purpose is not as brakes. This also raises stall speed meaning the wing will stall at a higher speed. So spoilers and spoilerons are different but their overall purpose for use is he same. The elevator compensation needed may be opposite.


Flaps and Flapperons

Flaps go down and increase the wing’s camber, makes the wing bottom more concave. This causes more drag and more lift while reducing stall speed allowing the plane to fly more slowly without stalling. That is why they help fast planes land more slowly. What we are looking for is not the breaking effect of the drag as much as it is the lowering of the stall speed which allows the plane to land more slowly. When flaps are deployed the increased lift will typically bring the nose up so we we compensate with down elevator to avoid stalling.

Flaps might be set to as much as 90 degree down angle, but 60 degrees is typically all you need for enhanced, slower landing speed.

If you have a glider with ailerons you can use them as flapperons. This works best when the ailerons are full span, like many discus launched gliders. Here you get full trailing edge control with only one control surface on each wing. You get thermal camber and reflex and you get flap behavior and spoileron behavior if you can get enough upward motion. This works best on a straight wing where any dihedral is at the root rather than a curved wing or a polyhedral wing where dihedral is introduce gradually over the length of the wing.


VERSATILITY

So, overall, flaps are more versatile than spoilers as you can use them to lower stall speed or increase it. However flaps are also more dangerous.

If you lower flaps, reducing the stall speed you can slow the plane down and keep flying below the normal stall speed. If you pull the flaps in because you realize you are not going to make the field you MAY stall because as you pull the flaps in the stall speed goes back up. If you are flying too slowly the plane will drop like a rock.

Spoilers on the other hand are more forgiving. If you apply spoilers too soon and realize you want to extend the glide you can retract the spoilers which lowers the stall speed. You will not stall and you will not drop out of the sky. The glide is extended. Personally I prefer spoilers for new pilots for this reason. Gliders with R/E and spoilers are called RES gliders.

Each approach has advantages. Flaps more versatile but more prone to error. Spoilers are less versatile but more forgiving of errors.

If I was modifying the trailing edge, I would make them flaps rather than spoilerons. However if I was a new glider pilot and wanted to avoid those stalling errors, I would install spoilers, not spoilerons.

I learned to fly gliders on a RES glider, a Great Planes Spirit. I fly RE, RES, REA and full house REAF gliders and I enjoy them all. But you fly them all a little differently. The more controls, the more versatile and the greater propensity for mistakes.

Of course, your smileage will vary.

F106A

My Feedback: (2)

Hi Art,
Thanks for the info.
I'm lucky in that I fly at Quakertown, PA-GREAT club! Everything from gliders to turbine's with a few heli guys for variety. Everyone gets along, we take turns flying our "stuff" and everyone has a great time. Being retired, I go out during the week and have the field mostly to myself, doesn't get any better than that.
AEAJR-thanks for taking the time for your post. When I flew gliders there were no flaps or ailerons, just spoilers so your info was very informative.
I think I'll get the 3.6 Pulsar Competition with REAF, it's only $20 more than the REF model. Just have to decide whether to use direct or geared motor.
BRG,
Jon

Art ARRO

My Feedback: (5)

Jon,
On the geared vs. direct choice, AEAJR should provide some you advice. Another question to consider is whether you plan to fly this sailplane for sport or competition. Competition tends to "high end" the choices that you may have, I fly sailplanes for sport although I have flown in competition but was never very good at it. Most of my "all-sailplane" buddies now fly for sport and enjoy it more. It's another thing to consider but you'll enjoy flying at the Q-town field. I maidened my BVM Maverick there many years ago.
Rgds,
Art ARRO

F106A

My Feedback: (2)

Hi Art,
I'm just a sport flier, I've never had much interest in competition, just didn't want to spend endless hours of practice; the payoff just isn't there for me.
Jon

aeajr

My Feedback: (2)

As far as gearboxes go, their major benefit is that they can be narrow to fit in the nose of a sailplane and nothing is spinning inside the fuse. If you have the room I would recommend a good outrunner as being lower in cost and typically quieter in operation

As for competition, unless you MUST win, I consider soaring contests as big fun flys where I get to fly with friends. No need or pressure to prepare or practice a lot unless you want to become a better pilot.

I also find contests to be the best learning opportunity around. But not everyone likes to advance their skills in this manner. That's fine. Each to their own, but I love contest flying. So much fun! I rarely win, but who cares?

BMatthews

Agreed, get an outrunner and run direct drive. Don't discount the losses in a gear system. Also it makes for a quieter model with the outrunner. Quite a bit quieter in fact.

One model with an old generation hot brushed motor and gearbox was updated to a brushless outrunner. The difference was the equivalent to running a glow engine without then with a good muffler.

Jimbonk

30+ years ago Radio gear was very expensive and had pretty limited functions. Designers got around the pricey and limited radios by using some pretty elegant designs. I had a Mike Smith design called a Sensoar, RES and FLAPS ! The flaps and the Spoilers worked off the same servo ( so wing cambering wasn't an option ). The systems was elegantly balanced so no change in pitch occurred ( ok maybe a little ) when you raised the spoilers/dropped the flaps. It was a bit fiddley to maintain but it worked . As for V-Tails , we are back to the lack of radio limitations , since the only other option was mechanical mixing. Bob Dodson did some really slick designs with all kinds of mechanical mixing including rudder/elevator mixing. He sold a lot of kits because of his great designs.

Spoilers are designed to kill wing lift and drastically increase the sink rate . Flaps create lift and cause a lot of drag slowing the airplane down ( and also reducing the stall speed dramatically ) . Where you really need spoilers is on the big Scale Ships (4M and up) . The glide ratio on these ships starts getting up to a level where landing them would take a really long run very close to the ground ( these scale will not have the oversize control surfaces that you see on our typical contest ships )

Jim