Hi guys

I'm fairly new to scale gliders and looking for advice from experienced guys. I have had 3 flights with this glider being towed up and it flies very well, seems to thermal very well and no bad vices. I most certainly want to refine my skills at the art of thermalling but my main interest is in doing like airshow sequences with music while managing the energy well on the way down. I'm am experienced F3A and IMAC Unlimited pilot and I think that interest of aerobatics has sparked my interest in doing, hopefully super smooth , aerobatics with this glider. Now I know that a Fox or similar would be better but this is what I have and I have seen similar fullsize doing some great displays regardless.

So from the little flying I have done with it I can see it has a fairly high lift wing, which is probably going to be fairly draggy during aeros compared to a Fox etc. I want to learn about reflex and snap flap or elevator to camber settings that I should use to get the best efficiency. What amounts of reflex I should give and how much camber/negative camber I should give as I pull or push the stick? Is there a common setup that is used?

My idea is to have 2 flight modes. A thermal flight mode and aerobatic flight mode. My thermal mode is what I'm already running and seems great but now want to setup the aerobatic mode. I want to firstly put some reflex at neutral elevator on the flaps and ailerons, I was thinking about 2mm up to try reduce some of the under camber this wing naturally has at the TE (For those experienced with this and this models airfoil, what would be best for least drag while diving?). As for the camber settings, I think I'm more interested in a elevator to camber mix over the snap flap feature as I want the airfoil to gradually change as more positive or negative G comes on. While pulling the stick back I would probably make the the reflex come off and only back to the neutral position of the control surfaces with no additional camber as its already quite a high lift wing and then while pushing the stick would want the reflex to continue the negative camber to about 5mm at a guess for best efficiency negative G manuevers.

How does that sound for a newbie?

Thanks TtT

Wow, what a cool post. You probably want to talk to Judge, who has both a background in glider competition and in IMAC, as well as being a former owner of a HKM 27, which is now part of my fleet. the HKM 27 suffers from the same disease that is common to older RC gliders, which is that they don't retain energy. I don't use camber but you could easily set it up on a switch to go full length ailerons or camber/reflex which would speed up the roll rate and increase the lift in thermals.
You could use reflex to maintain speed. Hopefully Bill will chime in or PM you directly.

Glad to hear there is another "Hakim" still flying!

Thanks, lets see if the thread takes off

As Paul noted I previously owned the exact same glider and I'll start off by saying it is an awesome flying glider, however, it is NOT an awesome aerobatic glider. This is simply because it does not retain energy very well. It is certainly up to doing a loop or two. 1/2 Cubans, stall turns (if you get enough speed going), split Ess, etc. It will spin, but it was not something I did a lot with. I share your interest in aerobatics and flew a lot of IMAC/Scale Aerobatics and a smattering of pattern. The ASW-27 is really a thermal glider and asking too much more than that might not be what you want.

There is really nothing special about the set up.

For normal cruise I flew it with the wing in section. My thermal mode had about 3 mm of camber straight across the wing. Reflex was about 2 mm across the wing.

I rarely use "snap flaps" and I did not on this. If you wanted to then I'd start with about 3 mm max. and see how you like that.

For landing mine was set up with 2 fixed flap positions on a switch. UP/HALF/FULL flaps. Mix elevator as needed to keep the nose from ballooning. I used the spoilers on the "throttle" stick. On landing I'd set my flaps at half for downwind and base, then go full flaps on final if I really wanted slow down. I'd use the spoilers as needed to control the touchdown point. The idea is to carry the spoilers just cracked on final. Add more if you are going to be long. Take them out if short.

This is exactly how you land a manned glider. Be aware that it WILL snap on you in low/slow turns. Keep the speed up in the pattern. Ask me how I know.

Mix UP elevator with spoilers to keep the nose in trim when using them. It becomes a balancing act between the flaps and spoilers for the elevator mixing.

I found the best way to tow was to minimize trying to turn. I'd let the tow plane "drag" me along. I would concentrate on keeping the wings level even when the tow plane was turning . I used the spoilers to keep from overspeeding. Their drag will keep the tow line tight.

It's a great thermalling plane, just don't expect much out of it when it comes to aerobatics. It is just not designed for them.

Does that help.

Thanks Judge that helps a lot. I appreciate your detailed post. I was thinking this airfoil would be a bit draggy for that type of flying but was hoping the reflex might help enough.
Thanks again.

Just as a matter of interest of learning:
How much of difference will ballast make with energy for aerobatic flying?
How much of a difference does the CG make for energy management?

funny, bill and I were talking about this the other day. you have an all composite, reasonably light glider that is good at what it is designed to do - thermal, or put the nose a bit on the slope. It is not an aerobatic ship and will resist any attempt to turn it into one. those long skinny wings will fly inverted, but they won't roll fast or axial. put some weight in it and I suspect you will find it a handful to fly.

What he said with the addition that moving the CG too far aft will not make it fun to fly. Don't ask me how I know!!

Like Pauls, it's an awesome scale thermal glider. It will move fast as well. But it is not made for aerobatics and will feel sloppy and lethargic if forced to do them.

Some other larger, heavier scale planes, even more classic thermal types, will do some passable simple aerobatics, but that is a function of their size and weight. You simply cannot load up the smaller 27 to turn it into a semi-aerobatic plane.

Thanks guys.

As I said above, its just a matter of learning and are general questions with any plane of how CG and ballast affects the energy management side.

I was thinking a nose heavy plane will have more drag with the elevators having to fight the extra nose weight where as a correctly balanced plane probably would not. Is there a noticable difference with energy in this case?

I know ballast makes a big diffence on slope soarers but does ballast make a difference with this type of aerobatics and how much is needed to notice any substantial difference?

Thanks again
TtT

Originally Posted by talkthetorque

Thanks guys.

I was thinking a nose heavy plane will have more drag with the elevators having to fight the extra nose weight where as a correctly balanced plane probably would not. Is there a noticable difference with energy in this case?

As with most planes when it is too nose heavy it will feel sluggish. Too far back and the pitch response is overly active with poor pitch stability. I forget the actual CG point, but I'd follow the recommendations of HKM. As far as energy retention, CG will not affect that much. It will affect how the elevator responds to inputs however.

I know ballast makes a big diffence on slope soarers but does ballast make a difference with this type of aerobatics and how much is needed to notice any substantial difference?

Since I never tried to trim it for aerobatics and only ever attempted to fly it outside its intended flight envelop a few times, I cannot comment directly how ballast will affect aerobatic ability in this plane. You seem intent on flying it as an aerobatic plane so I'd suggest experimenting with it a bit. Ballast will make it fly faster (read that as come down faster unless you are in killer lift) so that may help its aerobatic performance. Regardless of how much ballast you carry I would not diverge from the neutral CG point by very much.

So load it up, crank up your rates and go for it!! Take video!!

adding weight is only going to decrease the LD ratio and make it harder to land. as well as easier to stall. if you want to keep the speed up I would suggest a slider that will allow you trim the elevator with a little down when you want to fly aerobatics and can go back to neutral for approaches. The like other high aspect sailplanes, the 27 has a violent stall that takes altitude to recover and you don't want to find yourself fighting with the elevator close to the ground because you added a bunch of weight.