Author Topic: DT and drag ... (Read 438 times)

GScholz · « **on:** December 20, 2002, 03:39:45 AM »

I know DT weight is modeled, but the extra drag dosn't seem to affect my top speed at all. Anyone know if it is modeled?

Midnight · « **Reply #1 on:** December 20, 2002, 08:22:42 AM »

DT Drag is certainly modeled on the P-51s, so I can only think that it is modeled eveywhere.

SirLoin · « **Reply #2 on:** December 20, 2002, 08:52:29 AM »

I have to admit,it doesn't seem that noticeable though drag wise.

SLO · « **Reply #3 on:** December 20, 2002, 09:15:06 AM »

it does.......when you have 2 of em....level off get speed.....drop the tanks and your plane kinda jumps up.....

drop 1 of em..and your plane will lean on the side of the other DT still on....

as for drag...try diving with 2 of em....go fast and pull up.....you'll need much more room to pull up....

now drop em...your plane will respond much quicker to the pull up

maxtor · « **Reply #4 on:** December 20, 2002, 09:34:00 AM »

they slow down my planes sure nuff - sometimes they are handy in a dive for extra drag too.

Dowding · « **Reply #5 on:** December 20, 2002, 11:05:32 AM »

I should think they would have drag modelled. If not, then you might feel it is simply because acceleration is reduced because of the added weight. You could test it by flying straight and level for 30 mins or so (just to be safe); this gives the loaded plane time to overcome the acceleration difference. The maximum speed attained should be different between loaded and unloaded states, if drag is modelled.

Soda · « **Reply #6 on:** December 20, 2002, 12:32:36 PM »

I ran a number of tests on external loads and drag is there for sure. For example:
Typhoon 355mph @ sea-level with no WEP
Each 1K bomb cost 8mph
Each drop tank cost 8mph
each rocket cost 2mph
each 500lb bomb cost 5mph

Internal ordinance didn't seem to really cause much/any drag, a maximum of 1mph (lift induced drag most likely). Internal fuel loadouts also only affected top speed by about 1mph/25% internal. Once external stores were released, the plane reached top speed again (meaning that shackles/rails/mounting points) added no drag once the weapon was released.

I know I measured the Typhoon, P47, Mossie, Bf110, and some others, and it was very consistent.

-Soda
The Assassins.

Sancho · « **Reply #7 on:** December 20, 2002, 02:13:44 PM »

Try the P-47 with 150 gallon wing tanks. Compare top speed to P-47 with 75 gallon wing tanks. Also compare to top speed with tanks. You will find that the bigger the tank the slower you go.

GScholz · « **Reply #8 on:** December 20, 2002, 04:12:03 PM »

Thanks guys. Just didn't seem noticeable in the 190.

Btw. could be that the induced drag is the only effect modeled, anyone tried with an empty DT?

Soda · « **Reply #9 on:** December 20, 2002, 04:31:49 PM »

I tried full vs. empty configurations for internal fuel and ammo, but not on externals such as drop tanks. There was a different for internals, about 1mph / 25% fuel and 1mph for full vs empty ammo (all numbers at sea-level). I marked this up to lift induced drag for internal stores. Altitude affected the issue too, higher alts and speeds tended to show more drag and speed loss (I don't have the numbers for that offhand).

The real difference was in handling though. Try something like a 190A8 heavy vs light, even just on internal fuel, and you can immediately feel the difference. The top speed may only be effected by a couple of mph, but the plane just feels totally different.

-Soda
The Assassins.