Author Topic: Dive Breaks? (Read 392 times)

UnDeth · « **on:** July 12, 2002, 02:50:29 PM »

Does anyone know if Dive breaks work? I've tested them on several planes and I can't see any effect.

UnDeth

Kevin14 · « **Reply #1 on:** July 12, 2002, 03:00:31 PM »

I was flying a P38 with my buddy one time, same alt, same speed, he went into a steep dive and near the end he pulled out while I went screaming into the ground. So yes, they do increase the speed needed for compression

Majors · « **Reply #2 on:** July 12, 2002, 03:07:16 PM »

Hi Mates

Have extended the dive brakes on the SBD but they don't seem to slow it down that much in a dive. Looks good but not sure they work that well.

Majors
249RAF
Oldest Yank in the RAF

Animal · « **Reply #3 on:** July 12, 2002, 03:10:26 PM »

Dive brakes are not for slowing down, but for helping the plane come out of a compression. They somewhat work on the P-38L.

Widewing · « **Reply #4 on:** July 12, 2002, 03:25:48 PM »

Quote

Originally posted by Animal
Dive brakes are not for slowing down, but for helping the plane come out of a compression. They somewhat work on the P-38L.

In the real world, "dive recovery flaps" did several things.

1) Increased drag. Essentially, they decreased the acceleration rate, and reduced terminal velocity.

2) Shifted the center of lift forward along the chord of the wing, greatly reducing the much dreaded "Mach tuck".

In respect to the P-38, if the dive recovery flaps were deployed before or in the early stages of a dive, a neutral trimmed P-38 would execute a 3G, hands-off pullout.

Grumman would also join the dive recovery flat parade by installing them on the F8F-1 Bearcat.

My regards,

Widewing

Animal · « **Reply #5 on:** July 12, 2002, 03:31:59 PM »

JoeDirt · « **Reply #6 on:** July 12, 2002, 04:04:31 PM »

oops is right you fat drunk bastard!

akak · « **Reply #7 on:** July 12, 2002, 04:07:54 PM »

Quote

Originally posted by Widewing

In the real world, "dive recovery flaps" did several things.

1) Increased drag. Essentially, they decreased the acceleration rate, and reduced terminal velocity.

My regards,

Widewing

The dive flaps on the P-38L didn't increase drag like normal flaps but instead redirected the airflow over the surface wing to increase lift to help counter the compressibility problem.

[Source...Compressibility]

Ack-Ack
479th Fighter Group - Riddle's Raiders

Steven · « **Reply #8 on:** July 12, 2002, 05:57:00 PM »

Dive brakes on the SBD work. However, you have to chop throttle to nothing or you are defeating the purpose.

Kweassa · « **Reply #9 on:** July 12, 2002, 06:32:31 PM »

With dive flaps engaged on the SBD, a dive bomb run from 12k to 6k (6k drop) with throttle set to minimum increases speed by about 100mph. I'd begin the the dive at about 200mph, and the speed rarely goes up higher than 350mph. I'd say the dive break works pretty well.

ps) SBD is a very reliable anti-ship dive bomber. I survived every run I ever tried in the SBD with good results. Only weakness is the payload is very limited, so you are gonna need a lot of people in dive bombers to knock out a CV..

akak · « **Reply #10 on:** July 12, 2002, 07:01:00 PM »

Quote

Originally posted by Kweassa
so you are gonna need a lot of people in dive bombers to knock out a CV..

And just how it should be....

Ack-Ack

SKurj · « **Reply #11 on:** July 13, 2002, 12:50:28 AM »

Supposedly an SBD would hold a speed around 280mph with brakes dropped on a dive 'by the books' I am guessing that is throttle closed.

Sweet plane.. now i just have to find the handle to open that canopy!

SKurj

SKurj · « **Reply #12 on:** July 13, 2002, 12:54:01 AM »

Just curious widewing as you seem to be one of the most knowledgeable...

What about an airbrake on the F6f? I remember a model kit i built years ago had a panel i think it was behind the cockpit that raised?(been a long time could be in error).. and of course AW's F6 had a dive brake.

Also I have read about the practice of F6f pilots dropping their landing gear while divebombing as a dive brake. The gear wouldn't lock at speeds over 130mph..

Any truth to the above?

SKurj

UnDeth · « **Reply #13 on:** July 13, 2002, 01:56:37 AM »

Thanks for the posts guys. I'll work more with the P38 dive flaps and see how much it helps. I've noticed if I extend the dive flaps after I'm compressing it doesn't help much. I'll try extending prior to the dive and see if it helps.

UnDeth

akak · « **Reply #14 on:** July 13, 2002, 02:16:51 AM »

Quote

Originally posted by UnDeth
Thanks for the posts guys. I'll work more with the P38 dive flaps and see how much it helps. I've noticed if I extend the dive flaps after I'm compressing it doesn't help much. I'll try extending prior to the dive and see if it helps.

UnDeth

In order to avoid compressibiliy in the P-38, don't start your dives above 20,000ft. At least in the P-38, compression only happens at altitudes above that and not below 20,000ft. Using your dive flaps before entering the dive will help and will be pretty useless after you've entered the dive. In real life, one of the test P-38 planes had it's wings rip off when the test pilot decided to see what happens when he deployed the dive flaps in the middle of a dive.

One big misconception in here is that the dive flaps will help you in turn fights since it gives you about a 4 degrees nose up pitch. It doesn't help in turn fights since the nose up pitch only comes when at high speeds with the dive flaps deployed. The dive flaps aren't the same as the maneuvering flaps (i.e. Fowler Flaps, combat flaps) either. The maneuvering flaps are the first setting of your flaps. When you deploy the first notch of flaps, that lowers the flaps 8 degrees for maneuvering.

The photo below shows both the dive flaps and 'Foweler flaps" deployed.

Ack-Ack
479th FG - Riddle's Raiders