Author Topic: Is induced drag modeled in AH?  (Read 3394 times)

Offline save

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Re: Is induced drag modeled in AH?
« Reply #30 on: January 18, 2014, 05:18:51 PM »
25% of fuel in an A8 gives like 5-6 minutes of fuel on wep.

50% and 4*20mm is more representative for the A8 (base type of A8)
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Offline bozon

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Re: Is induced drag modeled in AH?
« Reply #31 on: January 19, 2014, 03:27:48 AM »
bozon: The prop and HP will have a huge effect on these curves.

Bigger HP planes will typically drop off much move at slower speeds do to not being able to convert the HP into thrust.

HiTech
So its a prop efficiency effect? I thought props were at their peak efficiency at slow speeds and efficiency does not change that much between good props. If anything, the Yak-3 probably has the highest power loading of the three planes.

Anyway, now that I did the math I realize that there is more than prop efficiency effects. When looking at the ROC/ROC_peak as a function of IAS plot some of the math becomes a little simpler, but still too much to post here - the slope of the back of the power curve (i.e. the drop of the ROC  below best climb speed) depends on the power loading with an additional dependency on the absolute mass ("power/mass^2" term in there) which is why the mossie "should" be doing so badly relative to the Yak3.

That still does not necessarily mean that the yak3 is OK - I don't have the numbers or the patience to calculate these graphs from theory, sorry. Maybe something is off with its "e" or "AR" parameters or too much engine power, IDK. It feels like one of those RedBull stunt planes, completely different from the other AH planes except the Spit16 perhaps. Not to mention that it takes as may hits as an F6F to bring down, while being a light, partially wooden, barely armored plane - but that is another topic.

25% of fuel in an A8 gives like 5-6 minutes of fuel on wep.

50% and 4*20mm is more representative for the A8 (base type of A8)
Yes, but for the testing I feared that the A8 will not fly at 110 mph with a heavier loadout...  :P
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Offline save

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Re: Is induced drag modeled in AH?
« Reply #32 on: January 19, 2014, 09:36:41 AM »
A normally loaded 190a8 have 105mph stall speed so you are way over   :cool:
My ammo last for 6 Lancasters, or one Yak3.
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Offline hitech

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Re: Is induced drag modeled in AH?
« Reply #33 on: January 20, 2014, 10:31:32 AM »
So its a prop efficiency effect? I thought props were at their peak efficiency at slow speeds and efficiency does not change that much between good props. If anything, the Yak-3 probably has the highest power loading of the three planes.

As a general statement that is correct. But remember Efficiency = Thrust HP / Break HP.

Think about the fact that at very very slow speed I.E when you start rolling the prop efficiency is way less then 10 % and increases to its max efficiency normally around best climb speed. As a general statement best climb speed is a "slow speed". Using the same prop but adding HP will add top end, buy may do nothing for the climb rate.

The issue is that as the engines got bigger it became very difficult to make the props bigger, hence more blades or paddle blade was traded off to increase climb at the expense of top speed.

HiTech

Offline Arlo

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Re: Is induced drag modeled in AH?
« Reply #34 on: January 20, 2014, 11:41:34 AM »
Thanks for being really into these details, HiTech. I never got the feeling the developers of other air combat sims/games really are.  :salute :cheers: :)

Offline Karnak

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Re: Is induced drag modeled in AH?
« Reply #35 on: January 20, 2014, 11:57:57 AM »
Thanks for being really into these details, HiTech. I never got the feeling the developers of other air combat sims/games really are.  :salute :cheers: :)
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Offline bozon

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Re: Is induced drag modeled in AH?
« Reply #36 on: January 20, 2014, 12:41:30 PM »
Thanks for the info HT  <S>
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Offline DaddyAce

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Re: Is induced drag modeled in AH?
« Reply #37 on: January 21, 2014, 07:34:49 PM »
Yes, thank you guys for the detail, clarification and respectful debate and clarification!  Dale it is your dedication to realism that has kept my subscription current even when I go through long periods where I may do nothing more than occasionally browse the BBS!   :salute

Offline GhostCDB

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Re: Is induced drag modeled in AH?
« Reply #38 on: September 06, 2014, 02:03:47 PM »
This thread makes my head hurt.  :bhead
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Offline Brooke

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Re: Is induced drag modeled in AH?
« Reply #39 on: September 06, 2014, 04:20:33 PM »
In the MA today, Skyyr was talking about how induced drag is not modeled in AH.  That is false, and I said so.  He told me that "even HT said that it wasn't modeled correctly."  I said that I was skeptical of such a claim.  He said to search around on his (Skyyr's) posts on the topic to verify that claim.

Well, here I am . . . again.  Now that I see what topic we are in, I remember this topic and see that I have posted in it already several times.

AH *does* model induced drag correctly; and, no, HTC *did not* say otherwise.

Offline Arlo

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Re: Is induced drag modeled in AH?
« Reply #40 on: September 06, 2014, 05:40:53 PM »
Was gonna give this thread a necro chiding but I see why it was given an add/bump. Sounds like Skyrr has a bad case of 'wanna believe I'm right no matter what' itis with a touch of 'so there.'

 :lol

Offline Skyyr

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Re: Is induced drag modeled in AH?
« Reply #41 on: September 06, 2014, 07:16:53 PM »
In the MA today, Skyyr was talking about how induced drag is not modeled in AH.  That is false, and I said so.  He told me that "even HT said that it wasn't modeled correctly."  I said that I was skeptical of such a claim.  He said to search around on his (Skyyr's) posts on the topic to verify that claim.

Well, here I am . . . again.  Now that I see what topic we are in, I remember this topic and see that I have posted in it already several times.

AH *does* model induced drag correctly; and, no, HTC *did not* say otherwise.


Wrong thread. Let me find the other one.
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Offline Arlo

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Re: Is induced drag modeled in AH?
« Reply #42 on: September 06, 2014, 10:38:48 PM »
Wrong thread. Let me find the other one.


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Offline FLS

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Re: Is induced drag modeled in AH?
« Reply #43 on: September 06, 2014, 10:48:14 PM »
I'm guessing it was HiTech's drag polar application comment.