Author Topic: F5 taking off and straffing (Read 1186 times)

MwXX · « **on:** May 08, 2005, 11:55:15 AM »

http://www.web-solutions.at/videos/1108759352.wmv

http://www.web-solutions.at/videos/1108759352.wmv

Enduro · « **Reply #1 on:** May 08, 2005, 12:59:59 PM »

thanks for sharing the vid.

Maverick · « **Reply #2 on:** May 08, 2005, 01:39:20 PM »

Great vid. I was surprised at the high cyclic rate of the guns as they aren't gattlings.

IMO that and the T38 are a couple of the best looking planes made.

Makarov9 · « **Reply #3 on:** May 08, 2005, 02:09:00 PM »

Beautiful planes. I so wish the F-20 Tigershark would have been produced.

GRUNHERZ · « **Reply #4 on:** May 08, 2005, 02:18:27 PM »

Quote

Originally posted by Maverick
Great vid. I was surprised at the high cyclic rate of the guns as they aren't gattlings.

IMO that and the T38 are a couple of the best looking planes made.

What you hear is about 4,000 rpm from it's two 20mm revolving breech cannon. Actually in those short burts these guns are faster firing than gatlings - which need a second to spin up to full cyclic rate.

Elfie · « **Reply #5 on:** May 08, 2005, 03:41:42 PM »

Quote

Originally posted by GRUNHERZ
What you hear is about 4,000 rpm from it's two 20mm revolving breech cannon. Actually in those short burts these guns are faster firing than gatlings - which need a second to spin up to full cyclic rate.

Thats not entirely true...

First, the M61A1 Vulcan cannon can fire up to 6000 rpm.

Second, the Vulcan cannon is powered by the aircrafts hydraulic system. From a *stopped* position to barrels rotating at full speed happens so fast you cant see the acceleration happening. (I've seen this with my own eyes)

I worked on an F-4E in 1982 that had problems firing its gun on multiple sorties. The barrels would rotate but the rounds werent firing. After multiple tests on the ground we finally put the aircraft on jacks, started the #2 engine, disconneted the firing lead from the gun, then depressed the trigger and checked for voltage at the firing lead. (All this was done to simulate the aircraft being airborne).

It's been so long since this happened that I forget what the problem ended up being. However, I was so impressed at how fast the gun accelerated to full speed that I can vividly recall that portion of what we did to this day. One second the barrels were sitting still, as soon as the trigger was pulled they were nothing but a blur.

1K3 · « **Reply #6 on:** May 08, 2005, 03:49:43 PM »

is F-5 the U.S. equivalent of the MiG-21?

btw those cannon fires sounds like fart!

GRUNHERZ · « **Reply #7 on:** May 08, 2005, 04:01:06 PM »

Yes the Vulcan has a higher top cyclicrate, but it is not instant like you think. Our percetion of time and what our eyes see is much different than the perception of time of something that fires 100 rounds a second. The gatling takes some time to spool up and it does result in lower ROF compared to revolver cannons on thge first trigger pull.

mora · « **Reply #8 on:** May 08, 2005, 04:05:45 PM »

Quote

Originally posted by 1K3
is F-5 the U.S. equivalent of the MiG-21?

I think the F-5 was more of a low-cost and barebones fighter, at least on western standards. It was built for export to less developed "friendly" countries, hence the nick name "Freedom Fighter".

Elfie · « **Reply #9 on:** May 08, 2005, 04:14:02 PM »

Quote

The gatling takes some time to spool up

From my experience that time is very negligible. In fact it's so negligible that it cant be seen with the naked eye. If the human eye can see the difference between 30 fps and 60 fps I have to believe it can see *spool up time* in one second.

When I worked F-15A/B's at Elmendorf AFB in Alaska many many times during combat turnarounds we were allowed to use the aircraft hydraulic system (while the #2 engine was still running) to upload ammunition to the gun system. The gun system never started off slow, rotation speed just happened as soon as you pulled the lever to rotate the system.

I would have to see some data that verifies that TWO single barreled cannons initially fire faster than ONE 6 barreled cannon in order to believe that.

Especially when you consider the cyclic rof for the TWO cannons is 2000 rpm LESS than the gatling.

Gunslinger · « **Reply #10 on:** May 08, 2005, 04:32:26 PM »

Quote

Originally posted by mora
I think the F-5 was more of a low-cost and barebones fighter, at least on western standards. It was built for export to less developed "friendly" countries.

we still use them accross the US as aggressors. They do great in that role of teaching ACM.

Elfie · « **Reply #11 on:** May 08, 2005, 05:01:16 PM »

So far I havent been able to find anything concerning spool up time with the gatling guns and how that affects the rof. I did find that the M39 cannons rof was 1500 rpm. Two of the M39 cannons combined rof is 3000 rpm, HALF that of the M61A1 Vulcan.

Imo there would have to be some serious spool up time on the Vulcan cannon to make a pair of M39 cannons faster firing than one Vulcan. Off to give Google another workout

GRUNHERZ · « **Reply #12 on:** May 08, 2005, 05:04:11 PM »

Its a factor elfie, tell me can you see tyhe difference between 70 rounds per second and 100 rounds per second with your own eye?

Gunslinger · « **Reply #13 on:** May 08, 2005, 05:12:45 PM »

Quote

Originally posted by GRUNHERZ
Its a factor elfie, tell me can you see tyhe difference between 70 rounds per second and 100 rounds per second with your own eye?

when you have less than a thousand rounds does it really matter the diff. between 100 and 70 RPS?

Elfie · « **Reply #14 on:** May 08, 2005, 05:23:39 PM »

Quote

Originally posted by GRUNHERZ
Its a factor elfie, tell me can you see tyhe difference between 70 rounds per second and 100 rounds per second with your own eye?

So post a link

As far as your question goes, I have no idea, never tryed it

The difference would have to be greater than the difference between 70 rounds and 100 rounds in order for the M39 cannon to fire faster than the M61A1. In fact it would have to be at least 51 rounds since a pair of M39's has half the rof (combined) of the M61.