E-F3A的動力

bike

彭大與Kevin您們好!
    子淳之所以會覺得電動機難控速應該是我的關係吧，我控速的問題很久以前在日本比亞太盃時，忠哥就有跟我提醒過了，飛行時我總是爬升比下降甚至比平飛快，我一直再努力改變及練習，不過在我想盡力表現出動作的柔和時，又不知不覺得越飛越慢，到爬升的動作時油門一加就衝過頭了，我有改變油門曲線來解決問題，將習慣的中速油門點提高，但簡單的說就是練不夠啦!!! 。
我有試過油機，感覺在速度上比較容易保持一致性，但做動作時油門的反應較慢故要提早一點帶油門，電機的在動力輸出上是無這狀況但油門的加減對空速有較明顯的改變，我想是電動槳徑大、重量輕的不同；我飛3A的這些年來會覺得電動的抗風性較差，主要就是認為槳徑大、空速慢在比賽時遇到風況不好時影響比油機大許多。
我以前有試過APC 22*12-E但頂風時根本飛不動，我大都用21*14或者21*13W居多，上次亞太盃有和草間匡人聊過，也向他的贊助商買了幾支手工木槳(貴死了)尺寸大約是19*15但槳身很寬目前正在適應中，它在爬升時的油門反應很明顯，頂風時也不會有飛不動的感覺，不過飛行的頓挫感更大，需要有更細膩的油門手感。
以上都是個人的感覺及經驗，也請彭大、Kevin或其他先進們指導賜教一番
                                                       JOY上

[ 本帖最後由 bike 於 2009年7月25日 12:06 PM 編輯 ]

lspeng

先告訴我你的動力配備: 馬達, ESC型號
再來是performance: 最常用的bench test是APC 21x14.全馬力時地面轉速, 峰值電流與負載電壓. 再來是飛完一個程序後, 全馬力時的峰值電流與負載電壓.  假如你有EagleTree飛行紀錄器, 這些資料都有.

我的感覺, 你的問題容易解決:
1. 以油門ATV限制高速上限. ESC必須用Fixed end point
2. ESC帶break

現今電機馬力比YS-160DZ不相上下. 我的Focus II油機改為電機時也是上昇比下降快(全備重量5420克), 我把ATV降到80%來解決. 減肥後(全備重量5190克)ATV降到71%. 宋老大的電機都在5000克之內, 油門ATV壓得更多.

我們用Castle Phoenix 85HV, 新版軟體有ramp mode break, 相當好用. 下降速度慢又穩

關於飛機晃動, 每架飛機的性能envelop不同. 以白話來說, 就是能穩定飛行的速度範圍. 以台灣能拿到機子為例,Skywing就是快速飛機,即使飛機做得很輕, 慢下來就開始晃. Integral的穩定飛行速度範圍就大得多,飛快飛慢都一樣穩.假如有機會去抓那架Shindan來飛(照片上有看到, 不知是誰的), 那是我看過性能envelop最寬的飛機;以速度差一倍來作程序,還是不晃動.

[ 本帖最後由 lspeng 於 2009年7月25日 12:56 PM 編輯 ]

ksung

Hi Joy,
I am going to try using English to reply, so please let me know if certain area you want more clarification.
In addition to Dr. Peng’s input, I will add the following.
My first impression after reading your post is your issue perhaps is more relating to the throttle management. If your downline is slower than your upline, and you are happy with your downline speed, than the problem is simpler to solver. At least this is an indication that you are not lacking with power.
From some of the pictures you have posted, it appears the motor you have is Hacker C50 Comp, but I can’t tell whether it is 13XL or 14XL. In either case, I am surprised to hear that 22x12 prop is that hard to fly in the wind. We have few e-pattern flyers around here, and they have been using 22x12 very successfully using the same motors you have, so as Dr. Peng has asked, perhaps you could share some of the performance data with us, so we can try to come up with more ideas.
Meanwhile, depending on the motor you use, APC-e 20.5x14 could also be a very good choice to try. I have used this prop many times, and I like it better than 21x13W. Keep in mind that there is really no one magic prop that will solve everything, only the one that fits you.
Regarding throttle management, it is good that you are trying to setup a throttle curve, and I would continue to encourage you to fine tune the curve to fit your style of flying. In my case, I set my curve to be less sensitive when flying straight and level, so the plane will lock in to similar flying speed easier. As for vertical line, I seldom use full throttle in the initial climb, but will add more throttle as needed to maintain the speed on the way up while control the height of the vertical. Finally, if you are using Futaba radio, you could consider setting up two different conditions for the throttle curve, where one is for windy days, and the other is for calm days.

Kevin

[ 本帖最後由 ksung 於 2009年7月25日 01:55 PM 編輯 ]

pandy

每次看彭大宋大发贴都会产生一些不解，引发我去学习和了解，所以先要感谢两位老大的耐心说明。
1、

以油門ATV限制高速上限. ESC必須用Fixed end point

设电机油门范围时，我是先将ATV设的较大，如120，再把throttle开到最大，然后esc通电，让esc检测最大油门，这时油门推到底产生最大功率。如彭大回贴所述，如果电机马力过大，可以靠减小ATV来实现，降到70% 80%，即保证动作实现，又能减小马力输出，不知是否正解？
另外，ESC 的 Fixed end point是个什么概念？

2、

ESC帶break

彭大的贴中常提到ESC的break 刹车功能。我的常识是飞电机也要设定个桨的怠速，不是收完油门后，桨靠惯性转一会儿才停下来，或者是立刻刹停，这个我是靠设遥控器的throttle cut来实现的。飞机从高空直落时，是想让桨产生一些阻力来减速，这时最理想的桨的情况是什么？所谓ramp mode break又是个什么东东？

3、宋大提到的油门掌握很有意思，我用的futaba早期的设备FF8UAP，没有图示油门曲线的功能，是否有多点油门控制功能还要研究下说明书。宋大提及的throttle more sensitive 或less sensitive值得好好去实践。以我现在刚入手电机的油门感觉是：在杆的前半程，电机没有什么力量，而过了半程油门，电机马力立刻爆发，再加一些油门，马力更大，油门前半程比gas engine逊色一些。为了改变这种感觉，我想就要学习motor throttle management。
以我现有的设备（FF8）可以设置throttle EXP，如果EXP往负值方向走，油门曲线如图１：

      图1
这样应当是油门前半段less sensitive,而后半段more sensitive.

如果设exp为正，曲线如图2：

图2  应当是油门前段more sensitive,而后段less sensitive.要改善我前面如说的电机油门前段软脚，是不是应当这样来设？是否适合较level的飞行风格。

如果能学到直升机的油门曲线设置，是不是我的FF8也能设出这样的多点油门控制曲线来呢？

图3 中段就非常sensitive
请宋大再结合图形说说throttle curve的设置 :)
我会带着这些问题去学习和试验。飞飞机学而时习之，不亦乐乎！
pan

[ 本帖最後由 pandy 於 2009年7月27日 09:15 AM 編輯 ]

ksung

Hi Pandy,

Regarding the throttle curve, you already have the correct idea, and by adjusting the throttle curve, it will help achieving more linear feel of the throttle.
In addition, you can fine-tune the curve to fit your flying style.
Keep in mind, different motor, ESC combination will have different output curve, which requires different adjustment.
In my case, the attached picture shows the curve I use, which works very well with my motor and ESC combination (Plettenberg 30-10 EVO / Castle HV85).
I hope this will provide you with more ideas about setting up your own curve, and in a way, help to maintain the constant flying speed throughout the pattern.

As far as your question-1 and 2, I will leave it to Dr. Peng to explain more in detail, but in general, the ESC we use (Castle Creation HV85), has two mode of end point for user to chose.
The auto mode is for ESC to check and auto calibrate the idle and full throttle position, it requires user moving the throttle stick from idle to full throttle every time before flying the plane to enable ESC’s auto calibration function, on the other hand, fixed endpoint allows user to manually set the idle and full throttle position, and once it is set, there is no additional work requires prior to flying the plane.
Additionally, fixed end point allows user to set full throttle ATV down lower to limit the maximum output.
In my case, I chose to leave the ATV at maximum, but use the throttle curve to fine-tune the output.

Brake (better yet, proportional brake) is another function available from HV85, where user can select different amount of braking power and how fast to engage the brake (ramp %).
Overall, this function allows user to fine-tune the downline speed; use it properly, along with a good throttle curve, will lessen much of pilot’s workload maintaining constant flying speed.

Hope this helps.

Kevin

lspeng

先來了解ESC的工作方式
每個廠牌的接收機工作電壓不同. 以Hitec來說, ATV上下都是100%為例, throttle在怠速時信號線的電壓約+0.4V,而全速時約+0.95V. Fixed end point就是在設定時告訴ESC, 上死點是+0.95V, 下死點是+0.4V.對這個固定範圍作scale-down調整才有意義.
Auto end-point是每次起飛前推大俥告訴ESC這是上死點, 即使你用ATV限制為+0.8V, ESC以為這個+0.8V是上死點, 那你的scale-down沒有意義

舊版煞車功能是把電極瞬間反接, 以100% power來煞車, 常伴隨巨大的撞擊聲, 而且突然的扭力變化會造成飛機瞬間甩尾

新版的ramp mode break是以程式控制: 多少%的power (一般用40%), 延遲時間 (一般用0.3秒).

以開車來說, 舊版煞車是一次踩到底的緊急煞車. ramp mode是輕輕踩的慢慢煞車