Hong Kong RC Sailplane Forum 香港滑翔機發燒友論壇

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PostPosted: 05 Jul 2005 11:30 pm 

Joined: 26 Jun 2004 09:59 am
Posts: 204
Location: Hong Kong
Best if durable and cheap, as a starting plane! Besides, seems that there is very limited selections at local shop and they are expensive! :roll:


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PostPosted: 06 Jul 2005 09:28 am 

Joined: 26 Jun 2004 09:59 am
Posts: 204
Location: Hong Kong
Found a 2.8m F3F hollow molded F3F for HK$3100 in Europe, but the shipping cost is another HK$800. Is the shipping cost really that high? Anyone have ideas? Thanks!


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PostPosted: 06 Jul 2005 10:23 am 
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Joined: 26 Feb 2004 05:08 pm
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Location: Hong Kong
Hi WingDragon,

Can you tell us what is that plane? 2.8M hollow molded for HKD3100 is attractive! :o

HKD800 shipping is average, but I think for this cost it is not shipped by express.


Just my little opinion: It is better to buy popular planes (e.g., Sting) if it is the first plane to you. Since they have proven performance, if it flew slow you know that you need more practice but not to change a new plane. And since many fellows have experience will them, you can more easy to get advise in flying and trimming the plane.


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PostPosted: 06 Jul 2005 01:23 pm 
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Joined: 12 Jan 2005 12:20 pm
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Location: Shatin (Tai Wai)
WingDragon wrote:
Best if durable and cheap, as a starting plane! Besides, seems that there is very limited selections at local shop and they are expensive! :roll:


Hi WingDragon

You may take a look into the rcgroups forum, there are some discussion re selection of F3F planes.

Another approach (also suggested by rcgroups) will be to start with a second hand F3F planes. With the introduction of top model like Aris / RaceM / Viking etc I guess some master may consider selling out their existing planes !

Just my 0.02 but you better prepare for "high-blood pressure" for flying with 3 metre planes. I only try once with Ah Wai's NYX, my fingers were all vibrating at that time !


Wing


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PostPosted: 06 Jul 2005 01:39 pm 

Joined: 26 Jun 2004 09:59 am
Posts: 204
Location: Hong Kong
Thanks Wing,

Let me check check sin!


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PostPosted: 07 Jul 2005 10:44 am 

Joined: 26 Jun 2004 09:59 am
Posts: 204
Location: Hong Kong
http://home.nextra.sk/pekarb/SK/albatros.html

But it uses RG15 airfoil which is kind of old design, I think it must be a slow flying glider.







Technické údaje:
Rozpätie: 2600 mm
Plocha: 50 dm2
Profil: RG15
Dĺžka: 1310 mm
Hmotnosť (bez RC súpravy): 1620 g
Konštrukcia: sendvičová


Detail vnútra trupu F3F verzie


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PostPosted: 07 Jul 2005 10:48 am 

Joined: 26 Jun 2004 09:59 am
Posts: 204
Location: Hong Kong
Price is EUR243, around HK$2250. 2 pieces plug in hollow molded wing with pre-installws push rod and pre-build flap and aileron using live hinges as told by the manufacturer.


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PostPosted: 07 Jul 2005 11:58 am 

Joined: 26 Jun 2004 09:59 am
Posts: 204
Location: Hong Kong
Quoted from the supplier:

A beautiful composite hollow molded sport sailplane by Pekar Model in Slovakia. All surfaces are finished and painted in the molds for a flawless external finish. Ailerons and flaps are pre-installed with gaps sealed. The gel-coated fuselage comes with pre-installed pushrods and rudder installed. The nose cone is removable providing full access to the radio compartment. The wings and full moving stabilizer are plug-in. Almost Ready to fly. Includes all necessary hardware and can be built in just one evening.
:shock:
Wing Span: 2600 mm
Wing Area: 60 dm2
Airfoil: RG15
Weight: 1620 g


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PostPosted: 07 Jul 2005 12:32 pm 

Joined: 26 Jun 2004 09:59 am
Posts: 204
Location: Hong Kong
Image
Image
Image
Image


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PostPosted: 07 Jul 2005 06:59 pm 
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Joined: 26 Feb 2004 05:08 pm
Posts: 2975
Location: Hong Kong
2.6m and RG15 :roll:

The Sierra from Art hobby is 2.5m and RG15. It is not fast.

Some older F3F/F3B design (Acacia II, Pike, etc) also used RG15 but they are fast.

So I think the airfoil is one of the many factors that determine the flying speed. But I agree that it is an important factor.


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 Post subject: Why large F3F planes ?
PostPosted: 12 Aug 2005 03:24 pm 

Joined: 02 Mar 2005 11:28 pm
Posts: 49
Location: Hong Kong
Saw serveral times 60" moldies flying almost as fast as those large F3F planes. Can anyone tell me why need to go for large F3F planes ? So costly to buy :roll:


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PostPosted: 12 Aug 2005 04:21 pm 
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Joined: 26 Feb 2004 05:08 pm
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Location: Hong Kong
MiniDick wrote:
Saw serveral times 60" moldies flying almost as fast as those large F3F planes. Can anyone tell me why need to go for large F3F planes ? So costly to buy :roll:


Not exactly :wink: 60" looks fast just because of their smaller size.

Just my humble opinion, I think big planes have several advantages:

1, Large wing is more efficient (high lift and low drag),
2. They are heavier and so can store up more energy - less susceptible to gust and more stable in strong wind / lift. So big planes can easily beat small planes in strong wind.

And I learn that good F3F turns can actually accelerate the plane. It seems that big plane is more efficient in this maneuver.

Any other comments from the masters? ( :o Stanley, :o Mak, :o Wai x 2, :o Kin, :x Pong-pong, :o YC, :o Angus . . . )


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PostPosted: 12 Aug 2005 05:31 pm 
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Joined: 26 Feb 2004 05:31 pm
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Location: 沙田
滑翔機快唔快好睇手指同 setting. 大機肯定唔係一定快過細機﹐但我自己飛完大機後就唔想番轉頭飛細機﹐手頭上依家一隻細機都無 ( handlaunch 除外 )。主要係因為飛大機有更大既空間可以探索﹐我地幾個飛大機都曾經試過隻機走 F3F track 會自己越飛越快﹐好似玩 DS 咁。個種速度真係幾得人驚﹐見過先至知道也野叫做快。箇中原因我地都唔係好肯定﹐有可能係因為飛機速度高﹐令雷諾數( Reynolds number ) 變大﹐機翼效率提昇﹐阻力降低﹐令飛機加速﹐速度提昇令雷諾數再大﹐將飛機推入一個加速循環。推隻機入呢個循環好睇轉彎既手勢﹐但一旦進入﹐就點轉都無也所謂。

呢種加速特性我只係見過大機有﹐細機就暫時未見過。可能同細機既機翼效率較低有關 ( aspect ratio 細D )。 但依家我地都只可以靠撞手神將隻機推入咁既自我加速狀態﹐如果有人可以練到野野做到﹐F3F 冠軍就非佢莫屬。點解要飛大機﹐就係因為大機先至做到呢樣野。


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PostPosted: 12 Aug 2005 09:43 pm 
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Joined: 26 Feb 2004 07:54 pm
Posts: 1660
Location: Tai Po, HK
我並唔係勿嘢 Master,不過都講吓自已既見解啦!
飛机係山岥飛行時,風不斷吹,所以飛机能夠不斷增加能量。風愈大、能量亦愈強。我地可以利用呢 D 能量將飛機向上升或加速。
玩 F3F 時,進入咗條 track之後,隻机就唔需要向上升。咁隻機就只能將風既能量化為向前既加速力,直至机身於高速飛行所產生既阻力,等同於机體受風吹所得既力量。
大机通常都可以造得比細机既阻力少,所以大机可以飛得快 D。 但係我哋一般都唔可以達到呢個自然既平恆點,因為每當對隻机做出任何不必要既動作,都會增加阻力既產生。特別係轉彎既時候,最容易做錯動作而另飛机減速。
大机其實係比細机容易控制,所以會飛得快過飛細機既。但係如果機手既技術高一班,咁細机都可以快過大机架。

我既見解係:飛行時要減少阻力既產生,咁先至可以發揮隻机既最佳速度。

如有錯誤,請大家指正 :)


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PostPosted: 13 Aug 2005 11:31 pm 
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Joined: 26 Feb 2004 06:07 pm
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Location: Hong Kong
F3F is the shortest time for 1,000m with 9 turns. If it is all about 1,000m straight track, a 60" racer may run as far as a 3m F3F planes. Bearing in mind that any plane loses energy and slows down in straight track no matter how well in aerodynamic design. You can only gain energy and accelerate in the turns or diving. Since the diving is prohibit in F3F, a good turn is the most critical part of the flight. A good turn is the combination of subtle control on aileron, elevator, rudder and flaps. Masters have different theories about F3F turn such as energy retention, drags, turning skills, etc. It is obvious that 3m plane has advantage in every aspect.

For the 1st F3F planes, it is not necessary to be those top guns. However, it should have proven record on the stability and performance. Popular is another major factor because someone can show you how to setup the plane. Each F3F plane has it own setting and characteristic. It is a painful exercise to obtain optimum setting via try-and-error.


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PostPosted: 13 Aug 2005 11:33 pm 
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Joined: 26 Feb 2004 06:07 pm
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Location: Hong Kong
F3F is the shortest time for 1,000m with 9 turns. If it is all about 1,000m straight track, a 60" racer may run as far as a 3m F3F plane. Bearing in mind that any plane loses energy and slows down in straight track no matter how good in aerodynamic design. You can only gain energy and accelerate in the turns or diving. Since the diving is prohibit in F3F, a good turn is the most critical part of the flight. A good turn is the combination of subtle control on aileron, elevator, rudder and flap. Masters have different theories about F3F turns such as energy retention, drag, turning skill, etc. It is obvious that 3m plane has advantage in every aspect.

For the 1st F3F planes, it is not necessary to be those top guns. However, it should have proven record on stability and performance. Popular is another major factor because someone can show you how to setup the plane. Each F3F plane has it own setting and characteristic. It is a painful exercise to obtain optimum setting via try-and-error.


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 Post subject: Re: Wrong
PostPosted: 26 Dec 2005 01:59 pm 
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Joined: 26 Feb 2004 05:08 pm
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Location: Hong Kong
nerve59 wrote:
Couldnt agree less. Totally off the chart. You can PM if you want, I will try to explain better...


:!:


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 Post subject: Re: Wrong
PostPosted: 26 Dec 2005 08:49 pm 
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Joined: 26 Feb 2004 03:51 pm
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Location: Hong Kong
nerve59 wrote:

Couldnt agree less. Totally off the chart. You can PM if you want, I will try to explain better...


WARNING!! This chap nerve59 is not geneous r/c soarer. He put down a link to a gambling web site and if you visit the site, it will set up a trojan virus there - be carefull!

I will remove all his links


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 Post subject:
PostPosted: 26 Dec 2005 11:40 pm 

Joined: 16 Dec 2005 01:20 am
Posts: 93
Angus wrote:
For the 1st F3F planes, it is not necessary to be those top guns. However, it should have proven record on the stability and performance. Popular is another major factor because someone can show you how to setup the plane. Each F3F plane has it own setting and characteristic. It is a painful exercise to obtain optimum setting via try-and-error.


Dear Angus,

I agree with you that a plane with proven record on the stability and performance is important. Therefore, I have acquired a second hand Sting recently, in December, 2005 though at the present moment I still not competent to land my 'Sky Walker'!

I fully appreciate it is a painful exercise to set a plane to its optimum condition via trial and error. The effort and gain ratio is so inappropriate.

I am not looking for the 'Optimum' setting, but I should be grateful if you would enlighten me on the 'Basic' setting of the 'Sting'.

Philip Shum


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