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megalopsuche
08-09-2009, 10:17 AM
Ok, it's at another forum, but this is probably the best analysis I have ever seen on how to use flaps correctly. I'm sure it will help many Il-2 pilots as well:

http://bbs.hitechcreations.com.../topic,271266.0.html (http://bbs.hitechcreations.com/smf/index.php/topic,271266.0.html)

megalopsuche
08-09-2009, 10:17 AM
Ok, it's at another forum, but this is probably the best analysis I have ever seen on how to use flaps correctly. I'm sure it will help many Il-2 pilots as well:

http://bbs.hitechcreations.com.../topic,271266.0.html (http://bbs.hitechcreations.com/smf/index.php/topic,271266.0.html)

Choctaw111
08-09-2009, 10:53 AM
Interesting, and it's even got the graphs and charts.

Kettenhunde
08-09-2009, 11:15 AM
One thing the article or the game does not take into account is the fact flaps greatly reduce the load factor an aircraft can sustain. The lower deployment speeds is due to structural limits at 1 G load. Increase the load factor and we quickly reach the point of structural failure for our airplane with flaps deployed.

It might be nice to hypothesis what we could do at 40 degrees of flaps pulling maximum G, the fact is anyone who has ever flow an airplane will tell you that is complete poppycock gamer fantasy. Just walk down to your local FBO and ask to rent an airplane to perform maximum load factor turns with flaps fully deployed. You could also call any aviation insurance company as ask for a coverage quote after letting them know your intentions.

One thing that is correct is the fact we reach the maximum benefit of flap usage in the first few degrees. Generally speaking the majority of the lift gains are realized the first 50% of the deployment range for a much smaller percentage of the drag penalties. The major portion of the drag penalty is generally realized in the later 50% of the deployment range.

While our structural limits are still reduced, small deployment increments do not realize as large a load factor reduction either.

This is why "combat flaps" only deploy a few degrees on aircraft equipped with them. The article also touches on why we don't see combat flaps on every WWII aircraft. Generally, it is not that designers did not understand flaps or have the ability to incorporate them either if level turn performance was desirable. As the article points out, not all designs will benefit from them.

All the best,

Crumpp

megalopsuche
08-09-2009, 11:42 AM
In AH, you can't deploy 40 degrees of flaps until you are way below the speed at which you could pull maximum G. Some aircraft can't even deploy the equivalent of combat flaps until they are below ~170mph.

Nonetheless, watching a Spit XVI rip its wings off in a break turn has to be one of the sweetest things in online air combat. http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

BillSwagger
08-09-2009, 11:49 AM
so they never used combat flaps in ww2?

not even 10% of flaps in turns.

Kettenhunde
08-09-2009, 11:56 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> so they never used combat flaps in ww2?
</div></BLOCKQUOTE>

Where does this conclusion come from???

Kettenhunde
08-09-2009, 12:02 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">In AH, you can't deploy 40 degrees of flaps until you are way below the speed at which you could pull maximum G. </div></BLOCKQUOTE>

IIRC,

The game enforces the white arc on the player. Which is ok, as long as you know the correct V-speeds and our aircraft is not under a load factor over 1.


All the best,

Crumpp

BillSwagger
08-09-2009, 12:27 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Kettenhunde:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> so they never used combat flaps in ww2?
</div></BLOCKQUOTE>

Where does this conclusion come from??? </div></BLOCKQUOTE>


I was asking because i wasn't sure, but it doesn't seem unreasonable that they could have used less than 10 degrees of flaps, even while flying above recommended speeds.

again, its not a conclusion or even based on any fact, but i do seem to recall reading that F4Us would often deploy "combat" flaps while engaging enemy fighters.


I thought i would pose the question because in game, deploying flaps beyond "combat" settings usually leads to jamming or damage, if you are flying above the recommended IAS.

JtD
08-09-2009, 01:02 PM
In game you can deploy combat flaps in any aircraft at all speeds, and I've never seen one where flaps would jam at speeds lower than 330 km/h IAS.

I use them a lot in slow speed maneuvers and it works very well. In some aircraft, like the P-38J, you're lost without them.

There are many accounts of the use of combat flaps in WW2. They were being used.

Kettenhunde
08-09-2009, 01:29 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I was asking because i wasn't sure, </div></BLOCKQUOTE>

No Problem. Combat flaps are specific to a design and will be listed with appropriate instructions for operating limits in the aircrafts POH.

Just because an aircraft can drop a few degrees of flaps does not mean it is equipped with combat flaps.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">it doesn't seem unreasonable that they could have used less than 10 degrees of flaps, even while flying above recommended speeds.
</div></BLOCKQUOTE>

In general, the shallower our flap deployment angle, the greater the structural strength of our flap design.

You can see principle nicely illustrated on the Bf-109 series:

http://img80.imageshack.us/img80/1378/109flapdeployspeeds.jpg (http://img80.imageshack.us/i/109flapdeployspeeds.jpg/)

All the best,

Crumpp

Kettenhunde
08-09-2009, 01:39 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">In game you can deploy combat flaps in any aircraft at all speeds, </div></BLOCKQUOTE>

The Corsair series is limited to 200KIAS in reality and the P38 series is restricted to 250 mph IAS for the maneuver flap position.

The POH stipulates that the aircraft may be maneuvering up to normal configuration load factor restrictions at or below these airspeeds with the maneuver flaps deployed.

All the best,

Crumpp

staticline1
08-09-2009, 01:43 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by JtD:
In game you can deploy combat flaps in any aircraft at all speeds, and I've never seen one where flaps would jam at speeds lower than 330 km/h IAS. </div></BLOCKQUOTE>

Actually you can't. Many of the early war a/c the flaps pop right back up if you're flying too fast. The F4F is a good example of that. Unfortunately the George is the complete opposite where they automatically deploy practically every instant you don't want them to.

JtD
08-09-2009, 01:44 PM
The F4F has an automated flap retraction system. It prevents noobs from damaging them.

triad773
08-09-2009, 06:11 PM
Decent read- thanks for posting that.

I have my flaps on a slider so it fits my setup. If I had stock button commands I don't think it'd be as relevant.

Cheers

Triad

R_Target
08-09-2009, 09:14 PM
F6F had automatic flap retraction also. It's not modeled in IL2 however.

http://i27.tinypic.com/2dhha1f.jpg

WTE_Galway
08-09-2009, 09:35 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by BillSwagger:
so they never used combat flaps in ww2?

not even 10% of flaps in turns. </div></BLOCKQUOTE>


Be careful with the terminology. Historically the term "Combat Flaps" was often used to denote a type of flaps - more specifically the Fowler Flaps installed on aircraft like the P38 ... which give extra lift without excess drag and the flaps on these aircraft were designed with the intent of being used in combat.

The barn door flaps installed on early spitfires and hurricanes on the other hand work more like air-brakes.

Kettenhunde
08-10-2009, 06:35 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">more specifically the Fowler Flaps installed on aircraft like the P38 ... which give extra lift without excess drag </div></BLOCKQUOTE>

Just to be clear, lift and drag are connected by design. Simply put, when lift increases, drag must increase as well.

There is not a free lunch.

All the best,

Crumpp

JtD
08-10-2009, 07:25 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by R_Target:
F6F had automatic flap retraction also. It's not modeled in IL2 however. </div></BLOCKQUOTE>

I didn't know that. Interesting that none of the quite-a-few reports I've read mentioned this. Is it true for all F6F models?

Thanks for pointing it out!

R_Target
08-10-2009, 07:02 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by JtD:
I didn't know that. Interesting that none of the quite-a-few reports I've read mentioned this. Is it true for all F6F models? </div></BLOCKQUOTE>

The pilot's handbook I have is for F6F-3, F6F-5, and their respective night fighter versions, so all models I guess. Also, I can't recall offhand any pilot anecdotes mentioning the progressive retraction either. I may have a Hellcat training film that mentions it, but can't remember. If I find anything, I'll put it up.