The A2A Simulations Community

I believe the starter speed of the A2A Simulations P-51D is way too slow.

I think it might be twice as slow as it's real world counterpart. I've rendered a video demonstrating why I believe this is the case.

The A2A P-51 takes about 6.4 seconds for 6 blades to pass. The real world P-51 takes about 3.2 seconds.



Below is another video.

Although more than 6 blades are rotated before the engine fires, you can still count 6 blades, and time it. In this video, I actually counted 6 blades passing in 2.7 seconds.

Far quicker than 6.4 seconds.



Thoughts? 6 Blades just seems to take a long time in the simulator. Maybe the starter needs to be beefed up?

_________________
My Guide On How To Fix Your X-52's Rudder!

i disagree. if you are basing this on nothing but the videos you are showing then sure. but these all look like it's warm engines. watch this video. ive warmed the engine and it does rotate faster. so based on what you've shown even mythbusters would disprove this.

http://www.youtube.com/watch?v=UCyHCzWUgKI

636,

Just a few things:

1. Temperature affects the battery output and oil thickness, so cranking speed is variable
2. Your youtube example showed some combustion (look carefully, you can see the prop lunch a few times)

However, your post here promoted me to run some tests against our own recordings and did find that under constant conditions, we are cranking somewhat too slow. We're just putting in what we hope to be a release update for the core accusim to beta now, and the starter torque has been increased. I think you'll like the update.

EDIT:
Lysodan, we double posted. Yes, you are spot on as we posted the same thing. The adjustments we just made are actually somewhere in between the video you showed and the one that 636 showed.

Both of you, thanks for posting.

Scott.

_________________
A2A Simulations Inc.

I see Scott has addressed this and we'll be speeding up the start a bit.

I would comment in addition to what has already been said that what you see on film clips that show Mustang starts is not necessarily good starting procedure. I've seen enough "diversion from correct starting procedure" when it comes to starting a Mustang in my career to write a book.
Add to this ambient temperature and primer fuel in the lines that can as well affect the start as well as engaging the starter with the mags hot and you have just a sample of some of the several starting scenarios available to someone starting a Mustang )
I've had Merlins crank for a considerable time before starting on cold days and had them kick over immediately as the mags went hot.
Starting a Merlin is never accomplished on a standard timeline. It's a variable for sure.
Dudley Henriques

Big thanks to all three of you guys.

I was aware of the oil temperature/battery deal.

I'm glad to hear you guys are tweaking the starter speed a bit, but I'll be curious to see what extent it's tweaked to.

I'm not one to second guess A2A team members, but I did a test just now after having my oil at 60 degrees, and I noticed very little - if any increase in the speed, with a brand new aircraft.

I'm also not 100% sure the Man O' War I'm comparing myself to in my video is warm. It's taken from the Roaring Glory series. Have a listen to Jeff's comment in this video at 1:02. It's from the same flight as the startup video on the left half of my clip. "The oil is still below 40 degrees centigrade..."

But if you guys have it nailed, then it suppose it's me.

_________________
My Guide On How To Fix Your X-52's Rudder!

If the ambient temps are just right and the oil is warm that's ONE factor that might get a quicker start. Add to this that a lot of Mustang pilots will engage the starter with the mags already on BOTH. This can greatly increase the start timing.
It's a pilot option to keep those mags off until the engine sucks up some oil into the heads and coats the rings. All you need to do is fork out the cash for a top overhaul ONE time and you'll be holding back on that mag switch just a bit longer to give that oil the chance to do what it does best )))))))
Dudley Henriques

One other thing to note as well is that most of these guys have newer starters on the engines that came off later model Merlins used in transport and heavy aircraft (like the Lancaster) which had a bit more "oomph" than the original. Jim Beasley's mechanic Rich talked about this some in his thread over on WIX. He also stated that the new Rousch Merlins have modern starter motors installed which are better than the originals. Between this and the modifications made to the engines themselves to make them run better, it's also very possible that some of the difference in rotation speed is also due to having an easier moving engine (due to better plating and bearings that have less resistance) and better starter motors allowing the starter to turn over the engine much faster.

If you watch the start of this F-51D, you'll see the rotation looks a bit slower for the 3 blades before it starts -

http://www.youtube.com/watch?v=MluFgIFD ... re=related

Also here -

http://www.youtube.com/watch?feature=pl ... hrE#t=478s

As the flight model is supposed to copy the original aircraft, the power of the starter should be based off of period film, not modern examples which have received modifications.

_________________

I would also say that the batteries in newer Mustangs may be different along with using a more powerful starter motor than the original. I would imagine that with the addition of VHF radios, radio navigation gear, etc. that the electrical systems in modern Mustangs may be modified to be a little more robust than original. Including using better batteries than were available at the time.

_________________
S Jordan
Milviz Staff Member
AM; United States Navy
FSX Hours: 2000 and counting