RC Slope Soaring in Hong Kong

Please treat the following light-heartedly or even consider it as a joke.

2. First of all, I must declare that I am a novice in the r/c soaring. I joined the HKRCSS on 20th November, 2005. I am not even competent to land my high wing trainer glider 'Sky Walker', at this stage. But, I am bold enough to acquire a 2.8m F3F glider, the Sting, last week. I think this is the benefits of joining a proper soaring society, without the guidance from the Masters in the society, I am afraid even with twenty more years in touch of the r/c soaring, I do not have the confidence to own a F3F glider.

3. As a novice, I wish to share some of my limited experience with other new comers to the r/c soaring world. I hope this will not become 'the blind leading the blind'. I sincerely hope that fellow soarers would give feed backs pointing out any wrong concepts I might have acquired, and put me in the right direction, especially in r/c soaring.

4. I understand there is no hard-and-fast rule on setting up a model r/c aircraft. There are so many factors affecting the setting and trimming, in particular the like and dislike of the individual pilot. They all have their own cup of tea.

5. Nevertheless, I wish to share some information about the 'Basic' mixing setting on the 'Sting':-

6. The 'Sting' is equipped with two Ailerons, two Flaps and a V-Tail.

7. First, plug in all the servos to the appropriate channel of the receiver. Switch on the receiver and transmitter.

8. Check all servo linkage and their neutral center. Sub-trim if necessary.

Set V-Tail

9. This function adjusts the elevator and rudder of V-tail models.

10. Use the remote control stick to check the Elevator and Rudder moving direction. If the Elevator and/or the Rudder is/are in the wrong direction, go to the 'Servo - Normal/Reverse' in the transmitter. Set the Elevator / Rudder servo to 'Reverse', one at a time, to see whether the Elevator / Rudder now moving in the correct direction. Normally, it will do.

11. If not, re-set the Elevator and/or Rudder servo back to 'normal'.

12. After that, go to the V-tail page on your transmitter, alter the +/- % of the Elevator / Rudder mixing. There are Elevator Rate 1 and Rate 2; Rudder Rate 1 and Rate 2, which can be changed. As a result, these settings control the rate and direction of moving of the V-tail reflection surfaces.

Set Aileron to Camber Flap

13. The aileron to camber flap is another basic setting for the Sting. When the aileron stick is manipulated, the ailerons and camber flaps perform aileron operation simultaneously and the operation characteristic of the roll axis is improved.

14. The left and right ailerons should have been set up properly before the following setting is carrying out.

15. Set the left flap moving in synchronization with the left aileron, by altering the +/- rate of the left flap. The travel rate of the flap may not be exactly the same as the aileron. Use the aileron as reference and alter the mixing rate of the flap, so the movement and rate of the flap is as similar to the aileron as possible.

16. Set the right flap and right aileron similar to the procedure as the left flap and left aileron. (if you prefer to set the right side first, then the left side, it makes no difference)

Set Butterfly (Crow)

17. Last but not the least, is the setting up of butterfly (Crow).

18. This function allows powerful brake operation by simultaneously raising the left and right ailerons and lowering the flaps. It is used when powerful brake operation is necessary, say for example, when approaching the landing path before landing. You are assisted by this setting to perform a 'slow and elegant' landing.

19. Normally, a switch on the transmitter will be employed. There is no fix rule as to which switch to use. My observation was that a number of Master in the HKRCSS use switch 'A'. Don't get me wrong, I do not mean that pilot not using switch 'A' is not a Master!

20. When the Butterfly function is employed, the 'throttle' stick, 'J2', controls the rate of the butterfly function. Of course, the stick arrangement will depend on what mode you are using. I understand most of the pilot in the HKRCSS use 'J2'. When the stick is at 'full throttle', i.e. push forward away from you, the butterfly has no effect. However, if the stick is pull towards you, the angles of the ailerons and flaps increased gradually. When the stick is pulled all the way down, the butterfly is at its maximum effect.

21. Nevertheless, when setting the butterfly rates for the aileron / flap; do not forget to leave some margin for the ailerons. That means when the butterfly is at its maximum effect, the ailerons still have effect.

22. Of course, there are other mixings to enhance the performance of your Sting, the above mentioned are only 'Basic' settings which are sufficient for your test flights.

23. I append below some of the rates appears on the current setting on my Sting, which a number of Masters have test fly it at Ma On Shan on 27th December, 2005. The setting seems acceptable.

24. Here are some of the sample rates:

V-Tail
--------------------Elevator Function--------Rudder Function-----------
Elevator (Rudder2) .. Down -50%.......... ----Left------Right-----
......................Up ...-50%..............+50%......+50%

Rudder (Elevator2).. Down .....-50%.......----Left-------Right-----
.....................Up .......-50%...........+50%......+50%

AIL to Camber FLP
-------------------Left--------Right----
FLP..............+80%.........+80%
FLP2.............+80%.........+80%

Butterfly
---Butterfly Mixing Rate-------
...AIL........AIL2
...-80%.......-80%

...FLP........FLP2
...+120%......+110%

The elevator requires a slight down rate in order to counter balance the 'Flap down' effect when the butterfly is employed, thus,

------ELE Correction Setting (within the butterfly)----
------Rate 1---------Rate 2------
ELE...+0%............-30%
ELE2..+0%............-50%

25. Please bear in mind all these settings will differ, say for example, if different types, maker or model number of servos and/or transmitter are employed.

26. After setting up your Sting in the 'Basic' configuration, it is always best to seek the advice from the Masters, and solicit their help to check and fine-tune the setting before conducting your test flight.

Philip Shum

Hi Philip,

You explanations of F3F settings are very good for beginner. I suggest those masters to share more information. I'd also declare that I am not a master yet.

I don't have a Sting so that I can't share the optimal setup. Perhaps, Stanley, Kin and Ping could provide more information.

For setting up a F3F ships, I'd suggest using "degree" or "mm" to measure the movement of control surfaces (ailerons, flaps and v-tails/x-tails) instead of "%" because "%" varies for difference radios, servos and other hardware linkages. For instance, you can follow this website to build a very simple and effective gauge -
http://www.f3x.com/htdocs/pagestuff/set%20up.htm

You can also find the proposed setup for Sting:

Normal Flying
Aileron: 25 deg up / 10 deg down
Elevator: 20 deg up / 20 deg down
Rudder: 20 deg up / 20 deg down
Aileron-to-flap mixing: 10 deg up and 5 deg down, depending on personal preference. (I switch off normally)

Movement of aileron controls the roll rate of the ship. In order to turn fast during F3F, the ship must responsive, i.e. with high roll rate. However, the ship will come very difficult to control if the roll rate is too high. Thus, you should find the optimal setting for yourself by adjusting the up/down movement slighting based on the propose setup.

Moreover, you may aware that upward movement of aileron is larger than downward movement, known as aileron differential. This means that the downward force is larger than upward force and the ship will point downward after a roll. This is not good for aerobic flight but it can facilitate acceleration after a F3F turn.

Butterfly/Crow/Landing
Aileron: 5 deg up
Flap: 85 deg down (as far as possible but remember to switch off before the ship touch the ground, otherwise flaps may be damaged)
Elevator: 8 deg up (fine-tune in flight)

The purpose of butterfly is to slow the plane for landing. Normally, braking force comes mostly from flap. Thus, it is recommended to drop the flap as far as possible. Upward movement of aileron provides little effect only. Elevator is the trickiest parts of entire butterfly settings. This value must be trimmed at flight. Optimal setting allows the ship to descend gradually before landing.

More settings and mixings will be discussed latter.

Dear Angus,

Thank you very much for enlighten me on the subject of F3x settings.

2. The 'Set-up sheet for F3x sailplanes' is very informative. As it mentioned '...many of the setting are the same. Believe it or not once you have a good 6 servo setup you can use it on many different models....'.

3. Yes, I agree with you that measuring the degrees on the surface is more precise. There is no need to blindly guessing, trial-and-error on the + / - rates on the transmitter.

4. I wish to listen to your further advice on the subject in the near future.

Philip Shum

Hi Philips,

We have been flying F3F planes for some years, when newcomers ask, we used to say; set it that way and it will work fine, and never really give them a more in-depth explanation. Thanks for pointing out the concern as a beginner for setting up F3F planes. I guess you have already dug out much of the information and Angus did also add many valuable points.

However, I would like to add a few points which I think are important though.

Aileron differential

This is quite important if you enter the turn level up. I have seen many pilots flew their planes with plane head up after the turn and this would slow down the plane a lot. This is particularly serious for those planes with bigger dihedral - like raceM. Of course, nowadays HK pilots have learned the technique to head downward a bit before turn and the head-up effect is minimal then. I normally build in the aileron differential mechanically when I install the servos on the wing.

Snap flap

This is a MUST for F3F as well as for dynamic soaring. Snap flap means when you pull up the elevator, the aileron and flap will be down to give a higher angle of attack so that the wing can generate more upward force to counter the centrifugal force while turn, the result is a much quicker and crispy turn. This is normally used when split-s turn is performed – the plane rolls to invert position and when the elevator is applied hardly with snap flap, the plane will quickly exit the turn with non-invert position.
The setting for the snap flap is very much depending on the plane design and the ballast it carries. Generally, 5mm to 10mm down would be a nominal range. The setting has to be patiently trimmed by yourself as different people have different styles. If too much snap flap is applied, the plane may result in spin after the turn. For me, I would like to pull as hard as possible without worrying too much about the spin, so I usually set it to the limit I want.

Butterfly

Angus said that the aileron is 5mm up when the butterfly is deployed. I think this is not quite right. As the flap diverts 85 degree down, the plane will have a positive attack angle for which down elevator must be applied to compensate for the plane upward till moment. And because of this compensation, the plane will not stay level easily at different speed during the course of slowing down for landing. To my experience, I would like to set the aileron upward range by minimizing the downward elevator compensation. My approach is to neutralize the elevator compensation first, and then set the aileron upward movement as much as possible, but not to affect much on the aileron movement important for steering the plane during landing. Then, if elevator compensation is still needed, apply it. If set properly, the plane can slow down gracefully without too much active correction.

Aileron/Rudder Mixing

Some pilots say this is useful because the plane can have a smoother turn if the rudder is turned synchronously with the aileron. In theory this will minimize the drag. Plane like RaceM has a moveable V-tail which significantly helps the plane in tight turn. I personally do not by default apply this setting in the transmitter as I found that different turns may need different mixing ratio. I turn the rudder manually if I need to. This gives me a closed-loop control on the turn. I don't know how the other pilots work this out.

Cheers

Hi guys,

First of all, I declare that I am not a master, and just is a new comer in F3F ( I had only joint the race for few times)

Concerning the mixing of Aileron/rudder, it is merely a personal preferance. It would be good for flying in light wind condition, as it decreases the air drag produced by the nose cone, as well as minimixing the height loss during turn. Normally, this called co-ordinated turn. However, it is not good for split-S, as employing this mixing would make the axis-roll not straight enough. Futhermore, it would not will on planes without dihedral.

We almost mentioned the major mixings, but I also set thermal flap and speed flap in my Sting.

The most important part for a well trimmed machine is CG, which is another long story.

Regards, and happy soaring,
Pong

Dear Pong,

Well, when you have time, please tell us more about thermal flap, speed flap anf CG.

Philip Shum

Dear Stanley,

I am afraid Angus was saying 5 degrees in stead of 5 mm.

2. As Angus already mentioned, he did not have a Sting, therefore these figures were quoted from the 'Set up sheet for F3x Sailplane'. So that, beginner like myself can have the information concerning 'Sting' readily available. Please do not forget there are setting for over a dozen of planes in the 'Set up sheet'.

Philip Shum

Dear Angus,

I almost forgot to mention the 'Home made Protractor' which is very good in deed.

2. With little bit of modification, it can measure 'mm' and 'inch' as well.

Philip Shum

Dear Stanley,

What is a 'split-s' turn? Is it the type of turn you perform at point 'A' and 'B' when you are flying the F3F track?

2. Do you always keep the Snap Flap on or use it with a switch?

3. What sort of rate do you apply to your Aileron differential?

Philip Shum

Split-S is what we usually do during F3F turns in Bases A and B. This is to roll the plane to invert position and wait for the signal from the Base, then pull up when the plane crosses the line. If your plane's setting is right and you pull up hard, your plane can be in non-invert position and exist the turn with speed.

I normally turn on the snap flap for F3F race and DS. It doesn't affect much for normal flying so it is up to you to switch it on all the time or using a switch to activate it.

I usually set the aileron differential mechanically when I install the servos on the wing. Generally, you only need a fair amount of, say, 5 deg on the servo arms.

Dear Stanley,

Thank you very much for your information.

Philip Shum

Dear Angus,

I refer to the 'sailplane set-up sheet'. Other than the 'Basic set up', I notice that there are figures for 'MAX Camber' and 'Reflex'.

2. What are 'MAX Camber' and 'Reflex'? In what condition and how they are deployed?

3. Please enlighten me.

Philip Shum

Dear Masters,

During the CNY holidays, do you have any free time to enlighten the beginners on 'Advanced Settings' ?

'Raindrops keep falling on my head', still flying your sailing planes in the open area ?

Philip Shum

哈哈﹗尋日仲係落雨﹐今日大年初一﹐此刻窗外陽光普照﹐藍天白雲﹐風光明媚。 天文台仲預測呢個禮拜尾會吹 5-6 級東風﹐睇黎狗年既兆頭真係非常唔錯﹐希望今年再度有新 F3F 香港記錄同埋有更多人參加呢項運動。再係呢度祝大家新年快樂﹗

Dear Y.C.,

Without proper advice from the Masters, how can beginners taking part in F3F ?

Philip Shum

Philip 兄,

Bring your Sting to Ma On Shan and we can setup together, if you are free on 30/1.

Angus

Dear Angus,

Thank you very much for your kind offer. I have to see whether I can squeeze some time on 30/1. By the time I send this message you have had an enjoyable morning on Ma On Shan already.

The original plan to go on 28/1 was met with 'Raindrops keep falling on my head'.

I fully understand 'hands on' is most crucial in the learning curve in r/c soaring.

Philip Shum